Welcome to OLGA 7 User ManualThis is the OLGA 7 User Manual. The user manual includes both information about the OLGA 7 engine and the OLGA 7 graphical user interface (GUI). The complete program documentation includes - Release Notes for OLGA 7 - OLGA 7 User Manual (this document) - Wells GUI User Manual - FEMTherm GUI Manual - OLGA OPCServer Guide - Installation Guide All documents listed above are available from the Start Menu (Start - All Programs - SPT Group - OLGA 7 - Documentation). The OLGA User Manual is also available from the Help menu in the GUI). OLGA is equipped with a context sensitive help document which can be opened directly from the user interface. The help can be reached in several ways: Click the Properties view and press F1 -> leads to the information on the relevant model Select Help from the File menu User Manuals for other tools included with the OLGA 7 installation (e.g. FEMTherm, Rocx, etc) are available from the Help menus in the tools.

Release InformationPlease refer to the Release Notes for detailed release information for OLGA 7. The Release Notes describes changes in OLGA 7 relative to OLGA 6.3, and should be read by all users of the program. The complete program documentation consists of the OLGA User Manual, Wells GUI User Manual, FEMTherm GUI Manual, OLGA OPCServer Guide, Installation Guide, and the Release Notes. The program is available on PCs with Microsoft Windows operating systems (Windows XP, Windows Vista and Windows 7). Several versions of OLGA may be installed in parallel. Note that you may also run several versions of the engine from one version of the GUI - please refer to the Installation Guide to learn how to configure the GUI for several engines. The support center provides useful information about frequently asked questions and known issues. The support centre is available from the SPT Group Support Centre Please contact SPT Group if problems or missing functionality are encountered when using OLGA or any of the related tools included in the OLGA software package. E-mail: olgasupport@sptgroup.com Telephone: +47 6484 4550 Fax: +47 6484 4500 Address: SPT Group AS, P.O. Box 113, N-2027 Kjeller

IntroductionOLGA is the industry standard tool for transient simulation of multiphase petroleum production. The purpose of this manual is to assist the user in the preparation of the input data for an OLGA simulation. In this manual you can find a general introduction to OLGA an overview of the required and the optional input to OLGA. It also describes in some detail different simulation options such as wax deposition, corrosion etc. a detailed description of all input data and the required fluid property tables a description of the output The sample cases presented with the installation of OLGA are intended to illustrate important program options and typical simulation output. A description of the sample cases are also included in this manual. OLGA comes in a basic version with a number of optional modules;FEMTherm, Multiphase Pumps, Corrosion, Wells, Slug Tracking, Wax Deposition, Inhibitor Tracking, Compositional Tracking, Single Component Tuning, Hydrate Kinetics and Complex Fluid. In addition there is a number of additional programs like the OLGA GUI and the FEMThermViewer for preparation of input data and visualisation of results. These optional modules and additional programs are available to the user according to the user's licensing agreement with SPT Group. See also: Background OLGA as a strategic tool OLGA Model Basics How to use in general Graphical User Interface Simulation model Input files Applications Threaded Execution

BackgroundOLGA 7 is the latest version in a continuous development which was started by the Institute for Energy Research (IFE) in 1980. The oil industry started using OLGA in 1984 when Statoil had supported its development for 3 years. Data from the large scale flow loop at SINTEF, and later from the medium scale loop at IFE, were essential for the development of the multiphase flow correlations and also for the validation of OLGA. Oil companies have since then supported the development and provided field data to help manage uncertainty, predominantly within the OLGA Verification and Improvement Project (OVIP). OLGA has been commercially available since the SPT Group started marketing it in 1990. OLGA is used for networks of wells, flowlines and pipelines and process equipment, covering the production system from bottom hole into the production system. OLGA comes with a steady state pre-processor included which is intended for calculating initial values to the transient simulations, but which also is useful for traditional steady state parameter variations. However, the transient capabilities of OLGA dramatically increase the range of applicability compared with steady state simulators.

OLGA as a strategic tool

OLGA is applied for engineering throughout field life from conceptual studies to support of operations. However the application has been extended to be an integral part of operator training simulators, used for making operating procedures, training of operators and check out of control systems. Further, OLGA is frequently embedded in on-line systems for monitoring of pipeline conditions and forecasting and planning of operations. OLGA can dynamically interface with all major dynamic process simulators, such as Hysys, DynSim, UniSim, D-SPICE, INDISS and ASSETT. This allows for making integrated engineering simulators and operator training simulators studying the process from bottom hole all the way through the process facility in a single high fidelity model. Note that the OLGA flow correlation has been implemented in all major steady state simulators providing consistent results moving between different simulators.

ApplicationsWhen the resources become more scarce and complicated to get to careful design and optimisation of the entire production system is vital for investments and revenues. The dimensions and layout of wells and pipelines must be optimised for variable operational windows defined by changing reservoir properties and limitations given by environment and processing facilities. OLGA is being used for design and engineering, mapping of operational limits and to establish operational procedures. OLGA is also used for safety analysis to assess the consequences of equipment malfunctions and operational failures. REFERENCES contains a list of papers describing the OLGA model and its applications.

Design and EngineeringOLGA is a powerful instrument for the design engineer when considering different concepts for hydrocarbon production and transport - whether it is new developments or modifications of existing installations. OLGA should be used in the various design phases i.e. Conceptual, FEED [2] and detailed design and the following issues should be addressed: Design Sizes of tubing and pipes Insulation and coverage Inhibitors for hydrate / wax Liquid inventory management / pigging Slug mitigation Processing capacity (Integrated simulation) Focus on maximizing the production window during field life Initial Mid-life Tail Accuracy / Uncertainty management Input accuracy Parameter sensitivity Risk and Safety Normally the engineering challenge becomes more severe when accounting for tail-end production with reduced pressure, increasing water-cut and gas-oil ratio. This increase the slugging potential while fluid temperature reduces which in turn increase the need for inhibitors and the operational window is generally reduced.

OperationOLGA should be used to establish Operational procedures and limitations Emergency procedures Contingency plans OLGA is also a very useful tool for operator training Training in flow assurance in general Practicing operational procedures Initial start up preparations Some typical operational events suitable for OLGA simulations are discussed below.

Pipeline shut-down

If the flow in a pipeline for some reason has to be shut down, different procedures may be investigated. The dynamics during the shut-down can be studied as well as the final conditions in the pipe. The liquid content is of interest as well as the temperature evolution in the fluid at rest since the walls may cool the fluid below a critical temperature where hydrates may start to form.

Pipeline blow-downOne of the primary strategies for hydrate prevention in case of a pipeline shut-down is to blow down. The primary aim to reduce the pipeline pressure below the pressure where hydrates can form. The main effects that can be studied are the liquid and gas rates during the blow-down, the time required and the final pressure.

Pipeline start-upThe initial conditions of a pipeline to be started is either specified by the user or defined by a restart from a shut-down case. The start-up simulation can determine the evolution of any accumulated liquid slugs in the system. A start-up procedure is often sought whereby any terrain slugging is minimised or altogether avoided. The slug tracking module is very useful in this regard. In a network case a strategy for the start-up procedure of several merging flow lines could be particularly important.

Change in productionSometimes the production level or type of fluid will change during the lifetime of a reservoir. The modification of the liquid properties due to the presence of water, is one of the important effects accounted for in OLGA. A controlled change in the production rate or an injection of another fluid are important cases to be simulated. Of particular interest is the dynamics of network interactions e.g. how the transport line operation is affected by flow rate changes in one of several merging flow lines.

Process equipmentProcess equipment can be used to regulate or control the varying flow conditions in a multi-phase flow line. This is of special interest in cases where slugging is to be avoided. The process equipment simulated in OLGA includes critical- and sub-critical chokes with fixed or controlled openings, check-valves, compressors with speed and anti- surge controllers, separators, heat exchangers, pumps and mass sources and sinks.

Pipeline piggingOLGA can simulate the pigging of a pipeline. A user specified pig may be inserted in the pipeline in OLGA at any time and place. Any liquid slugs that are created by the pig along the pipeline can be followed in time. Of special interest is the determination of the size and velocity of a liquid slug leaving the system ahead of a pig that has been inserted into a shutdown flow line.

Hydrate controlHydrate prevention and control are important for flow assurance. Passive and active control strategies can be investigated: Passive control is mainly achieved by proper insulation while there are several options for active control which can be simulated with OLGA: Bundles, electrical heating, inhibition by additives like MEG.

Wax depositionIn many production systems wax would tend to deposit on the pipe wall during production. The wax deposition depends on the fluid composition and temperature. OLGA can model wax deposition as function of time and location along the pipeline.

TuningEven if the OLGA models are sophisticated models made for conceptual studies and engineering will be based on input and assumptions which are not 100% relevant for operations. Therefore OLGA is equipped with a tuning module which can be used on-line and off-line to modify input parameters and also critical model parameters to match field data.

Wells- Flow stability e.g. permanent or temporary slugging, rate changes - Artificial lift for production optimization - Shut-in/start-up - water cut limit for natural flow - Cross flow between layers under static conditions - WAG injection - Horizontal wells / Smart wells - Well Clean-up and Kick-off - Well Testing - Well control and Work-over Solutions

Safety AnalysisSafety analysis is an important field of application of OLGA. OLGA is capable of describing propagation of pressure fronts. For such cases the time step can be limited by the velocity of sound across the shortest pipe section. OLGA may be useful for safety analysis in the design phase of a pipeline project, such as the positioning of valves, regulation equipment, measuring devices, etc. Critical ranges in pipe monitoring equipment may be estimated and emergency procedures investigated. Consequence analysis of possible accidents is another interesting application. The state of the pipeline after a specified pipe rupture or after a failure in any process equipment can be determined using OLGA. Simulations with OLGA can also be of help when defining strategies for accident management, e.g. well killing by fluid injection. Finally it should be mentioned that the OLGA model is well suited for use with simulators designed for particular pipelines and process systems. Apart from safety analysis and monitoring, such simulators are powerful instruments in the training of operators. [2] Front End Engineering and Design

OLGA Model BasicsOLGA is a three-fluid model, i.e. separate continuity equations are applied for the gas, for the oil (or condensate) and water liquids and also for oil (or condensate) and water droplets. Gas is always assumed to be lighter than oil and water in OLGA, but oil may be both lighter or heavier than water[1]. These fluids may be coupled through interfacial mass transfer. Three momentum equations are used; one for each of the continuous liquid phases (oil/condensate and water) and one for the combination of gas with liquid droplets. The velocity of any liquid droplets entrained in the gas phase is given by a slip relation. One mixture energy equation is applied; assuming that all phases are at the same temperature. This yields seven conservation equations and one equation of state to be solved: the seven conservation equations are three for mass, three for momentum, and one for energy, while the equation of state is for pressure. Two basic flow regime classes are recognised ; distributed and separated flow. The former comprises bubble and slug flow [2], the latter stratified and annular mist flow.

Figure A Flow patterns in horizontal flow Transition between the regime classes is determined by the program on the basis of a minimum slip concept combined with additional criteria. To close the system of equations, fluid properties, boundary and initial conditions are required. The equations are linearised and a sequential solution scheme is applied. The pressure and temperature calculations are de-coupled i.e. current pressure is based on previous temperature. The semi-implicit time integration implemented allows for relatively long time steps, orders of magnitudes longer than those of an explicit method (which would be limited by the Courant Friedrich Levy criterion based on the speed of sound). The numerical error is corrected for over a period of time. The error manifests as an error in local fluid volume (as compared to the relevant pipe volume). [1] Note that the OLGA model has only been verified and tuned for fluids where oil is lighter than water. [2] In standard OLGA a slug unit model is applied which calculates average liquid hold-up and pressure, but which does not give any details about individual slugs. To follow individual slugs through the system the slug tracking module must be applied.

NetworkIn OLGA the network comprises flow paths coupled with nodes which have a volume. General networks with closed loops can then be modelled, see below. The flow paths have a user defined direction but the flow is invariant to direction as such and any fluid phase may flow co-currently or counter-currently with respect to the pre-defined direction at any time and position. Pipe-bends are not accounted for as such (except for differences in static head). The user may apply pressure loss coefficients at boundaries between numerical sections. Equipment is positioned on the flow path usually on a pipe-boundary. However, the separator in OLGA is a network component similar to a node. Controllers are specified as integral parts of the simulation model and they have their own network formalism.

Threaded ExecutionPipe sections belonging to the same branch may be updated in parallel. Suppose a branch has 100 sections, and that two threads are available to the OLGA engine: Section 1 and section 51 will be updated simultaneously, then section 2 and section 52 are updated, and so on. Depending on the computer hardware, this method can drastically reduce the time OLGA takes to advance one time-step. Normally, you do not need to change the default settings of neither OLGA nor your operating system. Parallel updating of segments is usually activated in the OLGA engine if your PC supports it.

Controlling the degree of parallelismThe Windows operating system decides how many threads will be used. If your PC is equipped with a quad-core CPU, typically four threads will be simultaneously running to update four sections in parallel. Is your CPU a single-core Intel Xeon processor with "hyper-threading" (HT), probably two engine threads will be used. It is possible to overrule the choice of the operating system by setting the environment variable OMP_NUM_THREADS; use Windows' Control Panel to do this. However, the preferred way to change the degree of parallelisation is do so from the OLGA menu system. Setting the value here takes precedence over the OMP_NUM_THREADS environment variable. A situation where you might want to reduce the number of threads, arise if you execute parametric studies. Given that your license permits, it would be preferable to spend the CPU's cores on simultaneous simulations, rather than on speeding up each simulation in the study. Another situation could be when you don't want OLGA to consume all your computing power, e.g., if you want to write a report while OLGA is working. Most large cases will benefit from the parallelisation. Still, please note that some of your PC's cache memory will be used for forking and joining the threads, and doing the necessary book-keeping. As a consequence, special cases will run faster with a single engine thread.

Parallel speed-upThe parallelisation encompasses heat calculations in section walls, updating fluid properties and flashing, and, most importantly, calls to the flow model which decides friction factors, liquid holdup and the flow regime. If the flow model calculations dominate the overall simulation, the utilization of the CPUs is most efficient.

Monitoring the OLGA process

The Task Manager can be used to check how OLGA loads your CPU. When the number of engine threads equals the number of cores (or equals two on a single core HT-CPU) you should see the CPU usage being clearly over fifty percent when OLGA is simulating. In the Task Manager's list of processes it is possible to view the number of threads for each process. With 1 engine thread, it uses a total of 5 threads in batch mode, and 8 threads while running under control of the GUI. With 2 engine threads allowed, the task manager would display 6 threads for a batch run and 9 threads for a GUI run; with 4 engine threads the total number of threads would be 8 and 11, respectively.

Files and file extensionsWhen using the OLGA GUI understanding the different files used by the GUI and the simulator are not required. A basic understanding of the different file types is still useful when backing up files in Windows Explorer or running simulations from the command line. The figure below illustrates some of the files used by OLGA.

Project File (*.opp) The project file is a file with references to other files (e.g. case files) Case File (*.opi) The case file contains all user input in addition to graphical layout of the model, parametric study input and more. Generated input files (*.genkey) The genkey file is generated when starting an OLGA simulation from the graphical user interface (GUI). Output files During the simulation, the simulator will produce several types of output files. The most common are trend plots (*.tpl), profile plots (*.ppl), general output information (*.out) and restart files (*.rsw). The files with a ~ prefix e.g. ~Case-0.opi is the case file from the last save. With auto-save turned on for all case files in a project, files are saved at user-specified intervals.

Input filesThe OLGA simulator uses text files for describing the simulation model: .opi; generated and used by the OLGA GUI .inp; input format used by OLGA 5 and earlier versions .key; input format used by OLGA The .key format has been introduced as the new input file format for the OLGA engine. The OLGA GUI will automatically generate files in this format (with the extension .genkey). The .key format reflects the network model described in the simulation model and should be the preferred format. In addition to the simulation file, OLGA handles input in several other formats as described in Data files.

Simulation descriptionThe input keywords are organised in Logical sections, with Case level at the top, followed by the various network components and then the connections at the end.

Case levelCase level is defined as the global keywords specified outside of the network components and connections. Case level keywords can be found in the CaseDefinition, Library, FAmodels and Output sections. The following keywords must or can be defined at Case level: CaseDefinition; Case, Files, Integration, Options, Dtcontrol, Restart, Serveroptions, Udoptions Library; Material, Wall, Shape, Table, Drillingfluid, Hydratecurve, Timeseries, Tracerfeed, Udphase, Uddispersion, Udpdf, CentPumpCurve, Reservoirinflow Compositional; Compoptions, Feed, Udfeed, Blackoiloptions, Blackoilcomponent, Blackoilfeed, Singleoptions FA-models; Wateroptions, Fluid, Slugtuning Output; Animate, Output, Trend, Profile, Outputdata, Trenddata, Profiledata, Serverdata, Plot, Xyt Drilling; Tooljoint CASE PROJECT="OLGA Manual", TITLE="Example case", AUTHOR="SPT Group AS" INTEGRATION STARTTIME=0, ENDTIME=7200, DTSTART=0.1, MINDT=0.1, MAXDT=5 FILES PVTFILE=fluid.tab MATERIAL LABEL=MAT-1, DENSITY=0.785E+04, CAPACITY=0.5E+03, CONDUCTIVITY=0.5E+02 WALL LABEL=WALL-1, THICKNESS=(0.9000E-02, 0.2E-01), MATERIAL=(MAT-1, MAT-1)

Network componentsThe network components are the major building blocks in the simulation network.

Each network component is enclosed within start (NETWORKCOMPONENT) and end (ENDNETWORKCOMPONENT) tags as shown below. Each data group belonging to this network component will be written within these tags. NETWORKCOMPONENT TYPE=FlowPath, TAG=FP_BRAN ... ENDNETWORKCOMPONENT The following network component keywords can be specified (see links for further details on each component): FlowComponent;FLOWPATH, NODE ProcessEquipment;PHASESPLITNODE, SEPARATOR Controller;CONTROLLER ThermalComponent;ANNULUS, FLUIDBUNDLE, SOLIDBUNDLE FLOWPATHPiping

The flowpath can be divided into several pipes, which can have an inclination varying from the other pipes in the flowpath. Each pipe can again be divided into sections as described above. All sections defined within the same pipe must have the same diameter and inclination. Each pipe in the system can also have a pipe wall consisting of layers of different materials. The following keywords are used for Piping: BRANCH; Defines geometry and fluid labels. GEOMETRY; Defines starting point for flowpath. PIPE; Specifies end point or length and elevation of a pipe. Further discretization, diameter, inner surface roughness, and wall name are specified. POSITION; Defines a named position for reference in other keywords. BRANCH LABEL=BRAN-1, GEOMETRY=GEOM-1, FLUID=1 GEOMETRY LABEL=GEOM-1 PIPE LABEL=PIPE-1, DIAMETER=0.12, ROUGHNESS=0.28E-04, NSEGMENT=4, LENGTH=0.4E+03, ELEVATION=0, WALL=WALL-1Boundary&Initialconditions

For the solution of the flow equations, all relevant boundary conditions must be specified for all points in the system where mass flow into or out of the system. Initial conditions at start up and parameters used for calculating heat transfer must also be specified. The following keywords are used for Boundary & Initial conditions: HEATTRANSFER; Definition of the heat transfer parameters. INITIALCONDITION; Defines initial values for flow, pressure, temperature and holdup. INITIALCONDITIONS is not required when a steady state calculation is performed. NEARWELLSOURCE; Defines a near-wellbore source used together with OLGA Rocx. SOURCE; Defines a mass source with name, position, and data necessary for calculating the mass flow into or out of the system. The source flow can be given by a time series or determined by a controller. WELL; Defines a well with name, position and flow characteristics. HEATTRANSFER PIPE=ALL, HAMBIENT=6.5, TAMBIENT=6, HMININNERWALL=0.5E+03 SOURCE LABEL=SOUR-1-1, PIPE=1, SECTION=1, TIME=0, TEMPERATURE=62, GASFRACTION=-1, TOTALWATERFRACTION=-1, PRESSURE=70 bara, DIAMETER=0.12, SOURCETYPE=PRESSUREDRIVENProcess Equipment

In order to obtain a realistic simulation of a pipeline system, it is normally required to include some process equipment in the simulation. OLGA supports a broad range of different types of process equipment, as shown below. It should be noted that the steady state preprocessor ignores the process equipment marked with (*) in the list below. The following keywords are used for Process equipment: CHECKVALVE (*); Defines name, position and allowed flow direction for a check valve. COMPRESSOR (*); Defines name, position and operating characteristics of a compressor. HEATEXCHANGER; Defines name, position and characteristic data for a heat exchanger. LOSS; Defines name, position and values for local pressure loss coefficients. LEAK; Defines the position of a leak in the system with leak area and back pressure. The leak can also be connected to another flowpath to simulate gas lift etc. PUMP (*); Defines name, type and characteristic data for a pump. TRANSMITTER (*); Defines a transmitter position and the variable to be transmitted. VALVE; Defines name, position and characteristic data for a choke or a valve. VALVE LABEL=CHOKE-1-1, PIPE=PIPE-1, SECTIONBOUNDARY=4, DIAMETER=0.12, CD=0.7, TIME=0, OPENING=1.0Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUT(DATA); Defines variable names, position and time for printed output. PLOT; Defines variable names and time intervals for writing of data to the OLGA viewer file. PROFILE(DATA); Defines variable names and time intervals for writing of data to the profile plot file. TREND(DATA); Defines variable names and time intervals for writing of data to the trend plot file. TRENDDATA PIPE=1, SECTION=1, VARIABLE=(PT bara, TM, HOLHL, HOLWT) PROFILEDATA VARIABLE=(GT, GG, GL) NODEBoundary&Initialconditions

PARAMETERS; A collection keyword for all node keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. NETWORKCOMPONENT TYPE=Node, TAG=NODE_INLET PARAMETERS LABEL=INLET, TYPE=CLOSED ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_OUTLET PARAMETERS LABEL=OUTLET, GASFRACTION=-1, PRESSURE=50 bara, TEMPERATURE=32, TIME=0, TOTALWATERFRACTION=-1, TYPE=PRESSURE, FLUID=1 ENDNETWORKCOMPONENT

PHASESPLITNODEBoundary&Initialconditions

PARAMETERS; A collection keyword for all phase split node keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. SEPARATORBoundary&Initialconditions

PARAMETERS; A collection keyword for all separator keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. CONTROLLERBoundary&Initialconditions

PARAMETERS; A collection keyword for all controller keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. NETWORKCOMPONENT TYPE=ManualController, TAG=SetPoint-1 PARAMETERS SETPOINT=(2:0.1,2:0.2,0.3), TIME=(0,2000,2010,4000,4010) s, STROKETIME=0.0, MAXCHANGE=1.0 ENDNETWORKCOMPONENT ANNULUSInitialconditions

PARAMETERS; A collection keyword for all annulus keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the Annulus ambient conditions.AnnulusComponents

COMPONENT; A component to place within the annulus definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. FLUIDBUNDLEInitialconditions

PARAMETERS; A collection keyword for all fluid bundle keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the fluid bundle ambient conditions.BundleComponents

COMPONENT; A component to place within the fluid bundle definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. SOLIDBUNDLEInitialconditions

PARAMETERS; A collection keyword for all solid bundle keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the solid bundle ambient conditions.BundleComponents

COMPONENT; A component to place within the solid bundle definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file.

ConnectionsThe CONNECTION keyword is used to couple network components, such as a node and a flowpath. Each flowpath has an inlet and an outlet terminal that can be connected to a node terminal. Boundary nodes (i.e. CLOSED, MASSFLOW, PRESSURE) has one terminal, while internal nodes has an arbitrary number of terminals where flowpaths can be connected to. CONNECTION TERMINALS = (FP_BRAN INLET,NODE_INLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN OUTLET,NODE_OUTLET FLOWTERM_1) Separator and PhaseSplitNode have special handling of terminals.

The CONNECTION keyword is also used for coupling signal components. CONNECTION TERMINALS = (FP_BRAN Transmitter-1@INPSIG, SETPOINT-1 OUTSIG_1) See also connecting the controllers for more information.

Example fileThe keyword examples shown above can be combined to an OLGA .key file. CASE PROJECT="OLGA Manual", TITLE="Example case", AUTHOR="SPT Group AS" INTEGRATION STARTTIME=0, ENDTIME=7200, DTSTART=0.1, MINDT=0.1, MAXDT=5 FILES PVTFILE=fluid.tab MATERIAL LABEL=MAT-1, DENSITY=0.785E+04, CAPACITY=0.5E+03, CONDUCTIVITY=0.5E+02 WALL LABEL=WALL-1, THICKNESS=(0.9000E-02, 0.2E-01), MATERIAL=(MAT-1, MAT-1) NETWORKCOMPONENT TYPE=FlowPath, TAG=FP_BRAN BRANCH LABEL=BRAN-1, GEOMETRY=GEOM-1, FLUID=1 GEOMETRY LABEL=GEOM-1 PIPE LABEL=PIPE-1, DIAMETER=0.12, ROUGHNESS=0.28E-04, NSEGMENT=4, LENGTH=0.4E+03, ELEVATION=0, WALL=WALL-1 HEATTRANSFER PIPE=ALL, HAMBIENT=6.5, TAMBIENT=6, HMININNERWALL=0.5E+03 SOURCE LABEL=SOUR-1-1, PIPE=1, SECTION=1, TIME=0, TEMPERATURE=62, GASFRACTION=-1, TOTALWATERFRACTION=-1, PRESSURE=70 bara, DIAMETER=0.12, SOURCETYPE=PRESSUREDRIVEN VALVE LABEL=CHOKE-1-1, PIPE=PIPE-1, SECTIONBOUNDARY=4, DIAMETER=0.12, CD=0.7, TIME=0, OPENING=1.0 TRENDDATA PIPE=1, SECTION=1, VARIABLE=(PT bara, TM, HOLHL, HOLWT) PROFILEDATA VARIABLE=(GT, GG, GL) ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_INLET PARAMETERS LABEL=INLET, TYPE=CLOSED ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_OUTLET PARAMETERS LABEL=OUTLET, GASFRACTION=-1, PRESSURE=50 bara, TEMPERATURE=32, TIME=0, TOTALWATERFRACTION=-1, TYPE=PRESSURE, FLUID=1 ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=ManualController, TAG=SetPoint-1 PARAMETERS SETPOINT=(2:0.1,2:0.2,0.3), TIME=(0,2000,2010,4000,4010) s, STROKETIME=0.0, MAXCHANGE=1.0 ENDNETWORKCOMPONENT CONNECTION TERMINALS = (FP_BRAN INLET,NODE_INLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN OUTLET,NODE_OUTLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN Transmitter-1@INPSIG, SETPOINT-1 OUTSIG_1) ENDCASE

Simulation modelAn OLGA simulation is controlled by defining a set of data groups consisting of a keyword followed by a list of keys with appropriate values. Each data group can be seen as either a simulation object, information object, or administration object.

Logical sectionsThe different keywords are divided into logical sections: CaseDefinition; administration objects for simulation control Library; information objects referenced in one or more simulation objects Controller; controller simulation objects FlowComponent; network simulation objects Boundary&InitialConditions; simulation objects for flow in and out of flowpath ProcessEquipment; simulation objects for flow manipulation ThermalComponent; thermal simulation objects FA-models; administration objects for flow assurance models Compositional; administration and information objects for component tracking Output; administration objects for output generation Drilling; drilling simulation object OLGA Well; OLGA Well simulation object

Network modelA simulation model is then created by combining several simulation objects to form a simulation network, where information objects can be used within the simulation objects and the administration objects control various parts of the simulation. The simulation objects can again reference both information and administration objects. The network objects can be of the following types: Flowpath; the pipeline which the fluid mix flows through Node; a boundary condition or connection point for 2 or more flowpaths Separator; a special node model that can separate the fluid into single phases Controller; objects that perform supervision and automatic adjustments of other parts of the simulation network Thermal; objects for ambient heat conditions The simulation model can handle a network of diverging and converging flowpaths. Each flow path consists of a sequence of pipes and each pipe is divided into sections (i.e. control volumes). These sections correspond to the spatial mesh discretization in the numerical model. The staggered spatial mesh applies flow variables (e.g. velocity, mass flow, flux) at section boundaries and volume variables (e.g. pressure, temperature, mass, volume fractions) as average values in the middle of the section. The figure below shows a flow path divided into 5 sections.

Each flowpath must start and end at a node, and there are currently three different kinds of nodes available: Terminal; boundary node for specifying boundary conditions Internal; for coupling flowpaths (e.g. split or merge) Crossover; hybrid node for creating a closed-loop network The figure below shows a simple simulation network consisting of three flowpaths and four nodes.

The flowpath is the main component in the simulation network, and can also contain other simulation objects (e.g. process equipment, not shown in the figure above). It is also possible to describe the simulation model with a text file. See Input files for further descriptions.

OPC ServerIf asked for in the OLGA model, OLGA will run a server for OPC Data Access. OPC Data Access (OPC DA) is a specification for continuous communication of real-time data from a device to a receiving process. In the case of the OLGA OPC Server, the device is always the simulation of the current OLGA model, and the receiver could be a scheduler, a display or a simulator that implements a client for OPC DA. With the OPC Server, it is possible to interact with the running model. An OPC DA client connected to the OLGA OPC Server, may read output from the running simulation, and may also write values to the simulation. Through OPC, a process simulator or a user interface is allowed to connect to the OLGA simulation, and manipulate valve openings, well pressures, the setpoint of a PID controller or the massflow from a source. The OLGA OPC Server also have some special writeable items that serve as commands. By toggling SaveSnap or Stop, OLGA loads a snap file (i.e., a restart file) or stops, respectively. One uses the SERVEROPTIONS keyword to set up the OPC Server. Output is specified with the SERVERDATA keyword, which is very similar to TRENDDATA, and can be used with both trend and profile output variables. Input can be configured for certain keys in the keywords NODE, SOURCE, VALVE, WELL, and controllers; these keys form a set of parameters for the OLGA model being simulated. There are two modes for controlling OLGA's time-stepping: SIMULATOR and EXTERNAL. When the OLGA OPC Server is in SIMULATOR mode, one sets a speed relative to the computer's clock (say, ten times faster than real-time), and OLGA slows down its time-stepping process to try and keep this speed. When in EXTERNAL mode however, OLGA reads a time from the OPC Server, and steps forward until it reaches that time. The client updates the time on the server, and so the client takes control over the time-stepping. OPC DA relies on DCOM security, which can be difficult. A good understanding of DCOM security may be necessary to set up communication between a server at one computer and a client at another computer. Since OLGA owns the OPC Server, and removes it when it stops, it is not possible to set specific DCOM security for the OLGA OPC Server -- one has to rely on the general, default settings. It is usually quite easy to establish the connection when server and client is run on the same computer, by the same user, and both server and client is run as administrator. See the document OLGA OPC Server User Guide, found with the OLGA documentation, for further reference.

Graphical User Interface

Relationship between GUI and Simulation engineWhen starting OLGA there are two major components that come into play: OLGA GUI The OLGA GUI (GUI) is the graphical user interface which allows for the creation of new OLGA cases, editing input, starting simulations, viewing results and much more. This is what is described in detail in this document. OLGA Simulator The OLGA simulator is the component that performs the simulation. The simulation is usually started from the GUI but it can also be started independently (using a command line interface. The results from the simulation are stored in plot-files which can be displayed in the GUI.

Introduction to projects and casesAn OLGA case (model) is the collection of all the input data that is sent to the simulator when clicking run simulation. It normally consists of pipelines, process equipment and more to simulate the real world objects. In addition it contains information about simulation options, boundary conditions, etc. that influence the simulation. A case may also consist of references to other files like tab-files for fluid definitions, files with compressor characteristics etc. An OLGA project is a container for one or more OLGA cases and is a way of organizing relevant files. A project can contain other information like Word documents, reports, Excel calculations and more. The fluid files referred to in a case are automatically included in the project. When working in the OLGA GUI, work is always performed within the context of a project and will create a project when one doesnt exist. When a case is opened, the GUI will create a project for it and when closing the GUI it will prompt to save the project and the case(s).

Case toolbarToolbar icon Tooltip Duplicate case Remove case Save Save as Copy Paste Delete Properties Show Grid Snap to Grid Arrange Horizontal Ctrl+C Ctrl+V Delete button Double click on object Ctrl+S Shortcut key Description A new identical case will be created and added to the project Gives three options; remove from project delete or delete all output files as well Saves the case Opens a dialogue with the option to save the case with a new name Copies the selection Pastes the copied object(s) Deletes the selection Opens custom input dialogue if available or sets focus in the properties editor ; Rearranges the graphical layout with mainly

horizontal flow lines Arrange Vertically Fit to page Ctrl+Q Shows all local instances of the selected object in an editor table; all valves on one flowpath Shows all instances in a case of the selected object in an editor table Unlocks keywords generated in Well GUI Distributes the inline equipment on a flowpath equally Duplicates the selected object to all flowpaths / Adds selected object to the User's Library Opens the User's Library with a list of objects that can be imported Opens the parametric studies Opens a dialogue with easy configuration of bundles/annulus and burial of flowpaths Adds a OLGA well to the case, the Well GUI will be opened for configuration of the well Runs the simulation from a command shell window, independent of GUI Runs the simulation well integrated with GUI Pauses the simulation if run interactively Runs one step (only interactively) Option to configure the length of the step Shift+F5 F7 Stops the simulation Checks input file and reports errors and missing information in the output view Adds a plot tab to the case with the option to select and configure multiple plots Adds a trend plot to the case if trend variable(s) are selected Adds a profile plot to the case if profile variables (s) are selected Adds a 3D holdup profile plot Gives the option to plot the fluid properties defined in a tab file Opens an input report of the case F3 Saves a restart file (only available for interactive simulation and when the simulation is paused) Opens the out file in a text editor

Local instances Global instances Unlock Distribute Inline Equipment Duplicate to all Flowpaths Network connections Add to Users Library Import from Users Library Parametric Studies Copy as Image Add FEMTherm Add OLGA Well Run Batch Run Interactive Pause Step Step length Stop Verify Multiple Plots Trend Plot Profile Plot 3D Plot Fluid Plot Report Save Restart Output File F4 F5 F9 Ctrl+F5

Moving windowsWindows may be hidden and re-opened through the view menu. They may be detached from the frame (floating) and may be docked again by moving the window to the border of the frame. Double click on a floating window to move it back to the last docked position. In the picture below the blue area indicates where the window will end up if dropped at the current location. When the cursor is moved over one of the arrows towards the edge of the screen the window will dock on the corresponding border of the frame. When dropped on one of the four arrows in the centre of the screen the window will dock towards the corresponding side of the frame of the pipeline schematic window. Double clicking on the top bar of a docked window makes it float and double clicking on the top bar of a floating window makes it dock.

File viewThe File view shows the files associated with the project. This will typically be the input file as well as pvt-files and other files used in the case. However, any type of file can be added to the project (word-files, Excel-files etc.). By right clicking on a file the file can be removed or the input file can be opened in a text editor. The text file may be edited and reload it into the GUI by right-clicking the opi-file and selecting Reload from text file. Note that the graphical layout will be recreated on reload from a text file as the text file doesnt contain any information about the layout. This information is stored in the *.opi file.

Components viewThe Components view contains a library of objects that can be used to build the case. Simulation objects may be dragged from the Components window and dropped onto the Diagram view.

The view is divided into several groups: Flow Component Process equipment Boundary and Initial Conditions FA models Controller Results covering nodes and flowpath covering all equipment covering only boundary conditions keywords covering pigs covering all types of controllers covering interactive plots and values

Connections viewThe connections view gives information about the signal connections between transmitters, controllers, process equipment and boundary conditions. There are two modes: Display case and Display current object. Display case will show all signal connections for the entire case. Display current object will only show the signal connections for the selected object on the diagram view. The sample below shows that a PID controllers output signal (CONTR) is connected to VALVE-1s input signal (INPSIG). The INPSIG for a valve is the same as the valve opening. The transmitters (TM-1) output signal (which depends on the variable specified for the transmitter e.g. pressure) is connected to the PID controllers measured input signal (MEASRD).

Model view

The Model view is used for navigating between the objects of the system. The objects are ordered hierarchically with a project on top comprising one or more cases. A case contains Case Definitions, Libraries, Output and Network Components. Note that the model view lists all objects in the case whereas the diagram view only shows the visual objects. Nonvisual objects (for instance case options) are not shown in the diagram view but are listed in the model view. Case Definitions describe information common to the whole system being simulated. Network Components describe the properties of the flow network (currently either a node or a flow path). Libraries contain keywords that can be accessed globally (for instance Material and Wall). Output contains global output definitions, such as plotting intervals for trend, profile and output. FA-models contain input to flow assurance models. Compositional has input to the compositional model. Thermal Components contains input to the FEMTherm and bundle models and input to annulus calculations.

When selecting an object in the model view, the object is made active and its properties may be edited in the Properties view. The model view contains input for all cases in the project. Switching between the different cases is done by clicking on the file name in model view. Right-click while pointing to an object in the Model view brings up various menus depending on the object:

Add -> Exchange Geometry -> Verify Copy Paste Delete Unlock Local instances Global instances Add to users library Import from users library Properties

Add items to the network object.Only for flowpaths; updates the geometry with the geometry available from the geometry editor Checks input file and reports errors and missing input in the output view..

Copies selected item.Pastes the copied item onto the currently selected item.

Deletes selected object. Unlocks keywords created in the Well GUI. Shows all local instances of the selected object in an editor table; all valves on one flowpath. Shows all instances within the case of the selected object in an editor table. Adds selected keyword(s) to the users library. Imports from the available keywords/components from the users library. Starts the property editor for the selected object. For a flowpath this would be the geometry editor.

Case OverviewThe case Overview window is used for helping with orientation in the diagram view for larger network cases. The white frame shows what is visible in the diagram view; the size of the frame is dependent on the zoom level. The visible area can be moved by clicking and dragging (left mouse button) the white area.

If the case overview window is not visible it can be opened from the View menu, in the upper right corner.

Output viewThe Output view (not to be confused with the OUTPUT keyword/OUTPUT file) gives information about the state of the cases, modelling and simulations. The information is divided into three categories: Errors, Warnings and Info.

Error messages (and task list) : Cannot simulate o Errors in input o Errors from initialization phase o Errors during simulation o List of incomplete keywords. o Click on the symbol to go to the incomplete keyword

Warnings -

: The simulation may still be performed [1]

Information o Simulator state changes o Progress during simulation o Any messages during simulation (info previously directed to the DOS window)

The windows can be cleared from the context menu (right click). Text can be copied: Mark text Right click and copy Active Output categories, located in the top left of the output window, are indicated by an orange background colour.. A left mouse click on the text will activate or deactivate the category. By default the output from the active case is shown. Output from other cases can be selected from the pull-down menu at the top of the output window.

Navigator viewThe navigator view is only used when the Well GUI is active. The navigator then hosts the workflow of creating a well case. To find out more about the Well GUI please read the User Manual for Well GUI, a link is available from the Help page from the File menu.

Diagram viewWhen a case is opened or created the central window of the GUI displays a graphical view of the case. Below is a snapshot from the GUI with the template basic case, Case-1, loaded. The diagram view displays pipelines, nodes, process equipment and more. All visible objects are listed in the components view.

In the diagram view, nodes and flow lines are drawn schematically, not reflecting the real geometry of the case. Sources, pressure boundaries and process equipment are also visible. See also Editing a case using the Diagram view Context menus Network connection overview Configuration of separator/phase split nodes Configuration of controller connections Short-cut keys

Editing a case using the Diagram viewFlowlines Nodes and flowlines are drawn schematically. All objects shown in the component list can be dragged onto the diagram view. The process equipment needs to be dropped on a flowline to be added to the diagram view. By default the position of the equipment will be where it is dropped on the flowline. If the inline equipment is given a position (e.g. pipe and section) the position will be adjusted to reflect the real location along the flowline. Flowlines can be created either by dragging the Flowpath component from the component list or by dragging from the middle of a node or from a separators inlet and outlets. To disconnect a flowline from a node, select the flowline, left click and hold one of the green ends while dragging it away from the node/separator. Fixed points on a flowline can be added by selecting the flow line, click and hold the left mouse button and drag to where the fixed point should be added. A fixed point, indicated by a small square, will appear on the flowline. Fixed points can be moved to shape the flowline to improve the layout in the diagram view. This does not change the actual geometry of the flowline. Fixed points can be removed from the flowline by right clicking on the point and selecting Delete segment. Signal connections Signal connections are also based on dragging from one object to the connecting object. To disconnect a signal from an object, select the signal line, left click and hold one of the green ends while dragging it away. Fixed points on a signal line can be added by selecting the signal line, clicking and holding the left mouse button and drag to where the fixed point should be added. A fixed point, indicated by a small square, appears on the signal line. The fixed points can be moved to shape the signal line to improve the layout in the diagram view.

Context menus for diagram viewRight-click in the Diagram view activates a menu with the following items:

Arrange diagram horizontally Arrange diagram vertically Fit to page Snap to grid Copy as image

Rearrange the graphical layout with mainly horizontal flow lines Rearrange the graphical layout with mainly vertical flow lines Zoom in or out to capture the whole graphical network in the visible part of the diagram view Snaps items to the grid when moving them; will work even when the grid is not visible / Copies the diagram view or plot to the clipboard depending on what is in focus in the centre area

Right click in the diagram view on an object activates a menu with the following items:

Paste Bring forward Bring to front Send to back Edit visible signals...

.Pastes the copied item onto the currently selected item.

Local instances Global instances Import from users library Properties

. Brings the selected object forward. Brings the selected object to the front. Sends the selected object backward. Sends the selected object to the back. Opens a dialogue for selection of which controller signals should be shown graphically.(only available for controllers) Shows all local instances of the selected object in an editor table; all valves on one flowpath. Shows all instances within the case of the selected object in an editor table. () . Imports from the available keywords/components from the users library. . Starts the property editor for the selected object. For a flowpath this would be the geometry editor.

:

Network connection overviewConnection of flowlines and nodes can also be done through the Network Connection dialogue. The Network Connection dialogue can be access through the case toolbar or by right clicking on the diagram view and selecting Network Connection. Select the "from-to" nodes for each Flowpath and click OK. The network should appear as specified.

Configuration of separator/phase split nodesThe multi-phase coupling of a separator is performed in a similar manner as the coupling between a node and a flowpath. The coupling of a phase split node works again in a similar way as the separator. First, add a node and a separator to the case from the component view. Then connect the flowline from the node to the separator as follows: 1. Select the node and drag to the separator 2. Release on the separators inlet terminal

3.

Click on the outlet terminals of the separator one at the time (gas, water and oil) and drag

Configuration of controller connectionsAll out signals need to be transmitted through a transmitter in OLGA. This means that if e.g. the liquid level from a separator is required as input to a controller, a transmitter needs to be added to the separator first. The only exception here is the controllers which also can operate as transmitters.

The variable required from the separator must be specified as a property (key) on the transmitter. Coupling of signal components is possible with two different techniques in the graphical user interface; i) ii) Coupling with drag and drop - or Coupling through the connection view (see connection view)

Drag and drop coupling The drag and drop coupling between two signal components is done in the same manner as between two multiphase network components:

1. Hover over the component which the output signal is taken from. Click the component's blue dot (available out signal(s)) and drag towards another component in the network.Blue dots that appear when dragging towards a component are available input signals.

2. Release on the second components wanted input signal. A signal connection is made betweenthe two components. In the figures shown the out signal (equal to the variable listed for the transmitter at it's position) from a transmitter is connected to a PID controller's measrd input signal.

All available output and input signals are shown for all components except for the controllers. The controllers have many input and output signals. All controllers have a context menu item called Edit visible signals . This option will bring up the dialogue presented below. In this dialogue one can configure which signal that should be accessible/visible on the diagram view. for each type of controllers. The configuration will be saved with the case. Both the input signals and the output signals can be configured. By default only the required input signals are shown and the controller output signal, contr. Select which signals to configure, in or out. Then, select the type of controller if the selected one is not the correct one. check mark means that the signal will be visible on the diagram view. Note that all connected signals will be visible in the diagram view independently of the check marks.

Short-cut keysGiven below is a list of some short cut keys. for more information regarding short cut keys, see Case toolbar. Mouse wheel Ctrl+/CtrlCtrl+0 Ctrl+A Delete Shift+left drag Ctrl+left click/drag Zoom in or out in diagram view Zoom in or out in diagram view Return to un-zoomed view Selects all items in diagram view Deletes selected object(s) Pans Multi- select

Property editorThe Property editor displays the properties of the selected object. The objects can be altered by modifying the values of the different properties/keys. The left column is the property name, while the right is its value. Units may be altered. By default the value will update when the unit is changed. To keep the value, press the Shift key while changing the unit. When a property is selected, a description is shown in a region at the bottom of the Property Editor. Values may be inserted by typing them in one at a time or by selecting one or more values presented by the interface. The notation : can be used as multiplier, e.g. GASFRACTION=2:0,0.1 is the same as GASFRACTION=0,0,0.1. The colours of the property have the following meaning: Black : Property can be given but not required. Red : Property required. Grey : Property will not be used. Note that the colours of the properties will change as input is given. As an example: Two properties are mutually exclusive and one of them must be provided. Both will then initially be red (required). When a value is entered for one of the properties its colour will change to black (property is given and no more input required for that property) while the other property will change to grey (cannot be given). There are three options for sorting of data: Alphabetic: the keys are listed in an alphabetic order Original: the keys are sorted by key groups State: the keys are sorted based on selection (required keys and optional keys with value) and not used keys (optional keys without value and n/a keys) Some keywords have a special property page to make the process of entering data easier. These property pages can be accessed through the property editor button located in the top bar of the property editor window. See also Adding variables Time series editor Custom dialogues Centrifugal pump

Adding variablesClick in the VARIABLE field in the Properties window and then the - box.

Select variables from the window shown. The variables may be sorted: Alphabetically (by name or description) Categorized (as seen below) Those already selected (click the check box)

The units for plotting variables can be changed when actually plotting. There is also an option to specify a label for the variable selection and save it. These variables can then easily be re-used at several positions.

By clicking OK in the relevant variable selection window, all selected variables will appear in the Properties window:

By clicking OK, the dialogue window will close and focus will return to the properties window. Enter the pipe selection again and complete the specification by giving the section(s).

Time series editorInput keys with time series can be edited in a time series editor. The time series editor is accessed through the Property editor for the relevant keyword.

If there are several independent time-varying parameters within one keyword the graph of these can be displayed by checking them in the graph legend (which shows the minimum necessary input parameters).

Custom dialoguesSpecial editors are available for editing initial conditions and heat transfer statements. The input is graphically displayed together with the data. An example of an initial condition is shown in some detail below. An example of a heat transfer specification is also given. Initial conditions One can access the custom dialogue for initial conditions through the property editor button on the INITIALCONDITION statement. Note that this custom dialogue can only be accessed if only one initial conditions statement (keyword) exists. This custom dialogue can only be used when entering data section-wise. However, by selecting cells in a spread sheet and right clicking, a number of interpolation options are available. These will help input the desired data. Also, if incomplete data is given it will automatically be completed when exiting the editor. To activate the custom dialogue click the property button on top of the properties page, see below:

Heat transfer One can access the custom dialogue for heat transfer through the property editor button on the HEATTRANSFER statement. Note that this custom dialogue can only be access if only one heat transfer statement (keyword) exists. This custom dialogue can only be used when entering data section-wise. However, by selecting cells in the spread sheet and right clicking, a number of interpolation options are available. These will help input the desired data. Also, if incomplete data is given it will automatically be completed when exiting the editor. The heat transfer properties could be as shown below:

By clicking the properties icon of this window, the heat transfers custom dialogue is presented.

Centrifugal pumpPump curves are required input for the centrifugal pump. To help the user with the input, the pump curves together with some key parameters can be specified in a custom dialog. This can be accessed in one of the following ways: Double click on the centrifugal pump in the diagram view Select the centrifugal pump and press the Properties button in the case toolbar Select the centrifugal pump and press the property page button in the Properties editor

The following dialogue will then appear.

First, choose the centrifugal pump phase mode.

If phase mode = liquid (single phase), the option One speed per curve is given. This means that the only single phase curve will be used in the simulation. The multiplier for two phase will be ignored. There are two scenarios for curve input: This scenario is straight forward. The best efficiency point is used as rated values for the centrifugal pump. This scenario is straight forward if the input data follow Multiple speeds and one speed per curve the pump laws. If the data deviate from the pump laws, the generated pump curves will become bumpy, and might be difficult to use in simulation. An option to generate multiple homologous curves, which will be interpolated in speed, will therefore be added

Single curve

o o

If phase mode = two (two phase), the input data will be one curve per GVF (gas volume fraction), the options to choose between are: Calc multipliers - generates single phase curves from input with GVF=0. Generate two phase multipliers Calc multipliers and degraded head - generates single phase curves from input with GVF=0. Generate degraded head curves from maximum GVF given in. Generate two phase multipliers Interpolation in gas volume fraction - generates one single phase curve per GVF, and interpolate the curves using actual GVF

o

Secondly, decide to specify the rated values or chose the option to auto generate them. The auto generate option can be used if rated data is not available. Next, click on Add in the Pump curve frame to enter the pump curve data. First, enter the gas volume fraction and density. Note that the gas volume fraction needs to be 0 if phase mode = liquid (single phase no gas present). Further, choose which type of input data the pump curves should be specified in (head/delta pressure, and efficiency/head/torque), and then enter the data. At least three data sets need to be entered. When this is done, more pump curves can be added. Note that only the pump curves with a check mark will be used for the selected centrifugal pump. The centrifugal pump curve is a keyword named CENTPUMPCURVE, located on the library level. Several pump curves can exist. One pump curve can be used by several centrifugal pumps or not used at all. The Update plots button in the Normalized pump curves frame to the right will be enabled when enough information is given. The conversion of centrifugal pump curves to homologous curves will be then be performed. These curves are only for information; this is the input that will be used for the OLGA simulation. Several plots are shown: Single phase Head - two or more static curves Single phase Torque - two or more static curves Two Phase Head - two or more static curves Two Phase Multipliers - two or more static curves Head vs Volume flow - one static curve per centrifugal pump curve Torque vs Volume flow - one static curve per centrifugal pump curve

Note that the pump curves data can contain large errors that may give the curves a strange form. I order to avoid bad data, plot the input curves and the generated homologous

curves to adjust the input data. Navigating in the pump curve grid In the pump curve grid, use the tab button to move from left to right and use enter to move from top to bottom.

SimulationThere are some alternative ways to run a simulation, Run interactive and Run batch case by case or the entire project. Run interactive Run interactive makes it possible to open and view output results while running. An interactive simulation may be paused and continued. Run in batch Press Run Batch to start the simulation in the background. This will open a command prompt Showing output and progress. A batch simulation is running in a separate process than the GUI which means that it is possible to close down the GUI without disrupting the simulation. Run Project and Run Project Batch

If the project contains more than one case there are two alternative options, Run Project and Run Project Batch. These options are available in the project menu located in the upper right corner, and will run all cases in the current project in sequence. The sequence can be specified by setting the project dependencies. Project Dependencies can be access either from the i) Project menu or ii) By Right clicking the project in the Model View

Set dependencies in the dialog to obtain the wanted simulation order.

ReportsA case report is generated and viewed in the default web browser from Report on the case toolbar. The menu system in the report uses JavaScript which may trigger a security warning from the web browser. Allow the blocked content to activate the menus in the report. Use the buttons on the top to jump to specific sections in the report or check "Printer Friendly version to remove the menu system.

PlotsThere are several types of plots that can be activated in OLGA. Trend plots Profile plots Fluid plots 3D plots Interactive plots OLGA viewer See also Common behaviour in trend, profile and fluid plots

Common behaviour in trend, profile and fluid plotsAdding notes on the plot Add a descriptive note to the plot by selecting Edit Add Note from the context menu. The dialog allows text to be entered and attached to the case to one of the series in the graph.

Change or delete the note by right clicking it and select Edit Edit Note from the context menu. The notes can be toggle on and off by the notes button on the toolbar.

Use of the plotting context menu The plotting tool is a sophisticated program and provides access to several functions for modifying graphs. Most functionality is accessed through the context menu (right click on the plot to bring up the context menu)

File-menu Save As Image Displays a dialog for saving current plot to an image file Print Setup Displays a dialog for modifying print settings like portrait/landscape, margins etc. Edit menu Select This option is used to add and remove plot variables. This dialog can also be brought up using the Select button in the toolbar. Copy There are two options: copy the underlying data for the plot (to clipboard) or copy the current graph as an image (to clipboard). The size of the plot can be adjusted so that all copied images will get the same size (this can be useful when copying several plots into a report). Note(s) A descriptive note may be added to the plot by selecting Edit Add Note from the context menu. The dialog allows text to be entered and attached to the case to one of the series in the graph. Min/max values The minimum and maximum values can be adjusted on the axis to zoom in on a subset of the graph. By default the minimum and maximum values are reset when the plot file is reloaded. This can however, be turned off. Series... This option brings up the dialog below which enables changes to the title used for the series and change the colour and linestyle for the series.

Legend... This option brings up the dialog below which enables setting the font, font-size and position of the legends.

Axis... This option brings up the dialog below which enables editing the name of the axis, the format on the numbering, the position (top/bottom or left/right) and the colour of the axis. Note that for collapsed axis, only the position can be edited (the other options will be disabled for collapsed axis).

Titles... This option brings up the dialog below which enables editing of the header and footer. The visibility of the header and/or footer can also be set.

Slug statistics It is possible to plot slug statistics using the plot module. This is done by adding the plot variables LSLEXP (slug length) and LSBEXP (bubble length) to the trend data. Based on these plot variables two synthetic variables are calculated; LSLEXP_STAT and LSBEXP_STAT. By plotting these variables, a bar-chart will be created that shows the distribution of slugs/bubbles that have a duration which is a multiplicity of the given slug duration interval.

The slug duration interval and calculation time span can be changed using the dialog below.

Surge Volume The plot module will calculate and plot the surge volume if the plot variable ACCLIQ is included (accumulated liquid volume flow) as a plot variable in the trend data. The surge volume variables can be plotted as surge liquid volume (SURGELIQ), surge oil volume (SURGEOIQ) and surge water volume (SURGEWAQ).

The default calculation interval is from the simulation start to the end time. Default Qmax is given as: (ACCLIQ@endtime - ACCLIQ@starttime)/(Endtime-starttime) Start time, end time and Qdrain can be changed in the Surge Volume Options dialog (see below). Setting empty values in an option field causes default values to be used for this field, i.e. an empty value in end time cause last simulation time step to be used as end time.

View menu Black/White Collapse Axes If two variables use the same unit the axes for these variables will by default be collapsed. This option is used to switch between collapsed axes and individual axes for each variable. Legend This option is used to hide/show the plot legends Track Values This option is used to see the numerical values used as basis for the plot. Notes This option is used to hide/show notes added to the plot (see Edit-Notes above). Plot templates If the same plot is to be generated several times, the plot configuration may be saved as a plot template. A plot template includes information about the selected variables, sequence of selected variables, colours, units and more. Plot templates are convenient when running the same case several times or when several nearly identical cases exist (e.g. restart cases). To create a plot template the plot must first be configure, and then select FileSave As Template The template is stored as a .tpl.tz/.ppl.tz file in the location specified.

To use a plot template click on the arrow on the right side of the profile/trend plotting buttons.

Select template from the drop down with recent templates or select Browse to locate a template not in the list. A plot template can also be opened from within the plot (FileOpen Template). Note that a plot template will overwrite the current plot when opened this way. Export/import data to/from MS Excel Export data: In the Select variable dialog, mark the variables to export and then press the Export button. If desired, select export data to clipboard or to file. If exporting to file, a location and filename will need to be specified. The file can be opened in any text editor. If exporting to clipboard, the marked variable data is now copied to the clipboard and can easily be pasted into MS Excel. Some examples are shown below. Paste from Excel: Select data columns in and select copy. In Plot window right click and select Dataset->Paste.

Multi-case plotting It is possible to plot results from several cases/projects simultaneously. For example data from all the cases in a project can be plotted (use the Plot Project button in the select variables dialog). Several results files can also be opened via the Tools Plot menu, select several files, either trend (.tlp) or profile (.plt) or within the plot tool itself by adding files, see below.

Note that for profile plots where different plotting intervals have been used in the different files the profile closest to the selected time will be used and no interpolation is currently applied.

3D PlotsThe 3D plot shows the holdup for liquid along a single flowpath (pipeline length) in a three dimensional view. The plot is activated by defining the keyword ANIMATE at the case level:

Only the plotting frequency needs to be specified. After the case is run, click on the 3D plot button in the case toolbar to open a separate tab with the holdup view. This tab can be undocked and docked. Note if slugging appears in the simulation and slugtracking is turned on, the slugs will be identified in red.

3D plot toolbar:

Reset window Point view Pan view Rotate view Zoom view Context menu: Select Branch -> Animation settings >

resets the zoom level toggle point view toggle pan view (Shift+drag) toggle rotate view (Ctrl+drag) toggle zoom view (Mouse wheel)

// / // / ,

>Layout->

>

Fluid plotsThe plot-tool can be used to plot fluid-properties. Select Fluid Plot from the case toolbar and then open a fluid-properties file (.tab). Select the variables to plot and press ok.

The freeze-function as for profile plots can be used. Click the nail and then the play button. Clicking the nail multiple times allows for the freezing of more curves. The default x-axis is temperature. It can be changed by moving the column header fields in the right-hand side window to locate the "X-Axis" field (which is in the far right position by default) and select Pressure instead of Temperature (see figure below).

Interactive trend and profile plotsInteractive plots means that one can view a parameter while simulating and the data in the plot will automatically be updated. One has to define trend and profile variables through the SERVERDATA statement to be able to view these variables in interactive plots. The SERVERDATA keyword can be added through the model view on flow component level. Server data statements with only the variable given are treated as profile variables. If the position is specified the variables listed in the variable field are trend variables. All process equipment variables are trend variables and require that a position is given e.g. VALVE = valve label. Note: Server data given for a controller or specified with absolute position do not work for interactive plotting. Server data keyword placed on case level, will only work for global

variables in interactive plots.

After the plot variables are defined, interactive plots can either be added to the diagram view by dragging from the component list or opened as separate plot tabs. Plot tabs are created by pressing the Interactive plot button on the case toolbar or pressing the + on the right most side of the tabs. Note. For profile plots one can only see the last available profile, no history is saved. In the plot tabs within the case, one can add several plots to one frame. An example is shown below. Each individual plot can be configured through the context menu.

Context menu:

Edit/select Variables Opens the variable selection dialogue Remove All Variables Removes all variables in selected plot Toggle automatic pop-up of the variable selection dialogue (only used for Show variable selector the plot and value on diagram view) Max/Min Settings Open a dialogue to set the max and min values of the axis Edit X-axis Unit Makes it possible to change the unit of the x-axis Show border Toggles the border around the plot Load Layout from Opens a dialogue to specify a saved layout File Save Layout to File Opens a dialogue to save the layout Add Plot Option to add a plot above/below /right/left of the selected plot Remove Plot The selected plot will be deleted Remove All Plots All plots in the plot tab will be deleted Edit Title Opens a dialogue to edit the plot title Layout-> Options to change the plots position and size Copy -> Options to copy image/data Configuration Opens a configuration dialogue to edit the selected plot View-> Select type of plot - post processed or notThe context menu for the plots added to the diagram view contains a subset of the above menu. Single values added to the diagram view have the following context menu: Edit/select Variables... Show variable selector Show boarder Show Name

Opens the variable selection dialogue Toggle automatic pop-up of the variable selection dialogue (only used for the plot and value on diagram view) Toggle the boarder around the value and name of the variable Toggle the variable name

Profile plotsProfile plots are variables plotted along a distance (flowpath). There are many different profile variables. A list of the different profile variables are given in the variable section. A profile variable needs to be added to the case before the simulation is started to be able to plot it afterwards. Profile variables can be added on case level and on flow component level through the keyword PROFILEDATA. In the profile data statement the user has to select a variable e.g. VARIABLE = PT (pressure). One can read more about the PROFILEDATA in the Keywords section. The plotting frequency is given through the keyword PROFILE on case level. All profile variables use the same plotting frequency. Note that the plotting frequency can never be lower than the time step of the OLGA simulation. To view the profile plot, select the profile button on the case toolbar and then select the variable(s) to plot:

It is possible to "play-back" the profile plot, either by dragging the slide or by clicking play. The keyboard arrows can also be used to navigate; in the profile plot integrated in the case tabs use the key ctrl in combination with the right and left arrows. One can also freeze a curve by clicking the nail button. Each time the button is clicked, a curve is stored. To "un-freeze" a curve, disable the nail clicking stop. Several profiles can be played back simultaneously; however, the speed will depend on the capabilities of the PC. . Play-back is stopped by

Trend plotsTrend plots are variables varying with time e.g. how the pressure varies with time at a given location. There are many different trend variables. A list of the different trend variables are given in the variable section. A trend variable needs to be added to the case before the simulation is started to be able to plot it afterwards. Trend variables can be added at the case level and at the flow component level through the keyword TRENDDATA. In the trend data statement the user has to select a variable and then a position e.g. VARIABLE = PT (pressure) and position given e.g. by ABPSPOSITION = 100 m. One can read more about the TRENDDATA in the Keywords section. The plotting frequency is given through the keyword TREND on case level. All trend variables use the same plotting frequency. Note that the plotting frequency can never be lower than the time step of the OLGA simulation. After the simulation is run, select trend plot from the button in the case toolbar. This gives the Select variable dialogue below. Select the variables to plot. Double click on the selection or right click and choose one of the options displayed. Click OK to see the graph.

There are many ways to filter the content of the dialogue above. Note that filtering is a tool for locating the variables. The selected variables are plotted even if they are filtered away.

File menuWhen starting OLGA the File menu will appear with New in focus. From the New page, a case can be created by selecting an empty case or a Template. The templates are complete cases that are ready to simulate. The File menu can be accessed by clicking on File at any point in time. To exit the File menu click either on the File tab again or on a case tab.

The File menu covers the following: Save Project Saves the project and all open cases Saves the project and all open cases with a new name Opens a case of file type *.opi, *.inp or*.key Opens a project of file type *.opp Opens a case of file type *.geninp or *.genkey Closes the project with option to save project New case or project can be created in this page

Save Project as

(Ctrl+Shift+S)

Open Case

(Ctrl+O)

Open Project

(Ctrl+Shift+O)

Import

Close Project

New

Recent

Tools

Help

Options

Exit

Recent projects and cases are listed in this page Internal and external tools can be accessed in this page Information about manuals, sample cases and support Opens the options dialogue Closes OLGA with the option to save project

NewNew cases or projects are created from the New page. A new project is created by clicking on the Empty project icon. This opens a file dialoueg to specify the location and name of the project. A new case is created either by selecting Empty case or by choosing an appropriate template. An empty Well case is created from the New Well icon. There are two ways to select a template for a new case: From the carousel view or from the icon view. The template view is selected with the two toggle buttons in the top right.

In carousel view, the templates can be navigated sequentially and shows a preview of the network and a description of the template. The selected template is the front most template highlighted in the orange selection colour. Navigation is done by clicking to the right or left of the selected template which will scroll the new selected template to the front. This can also be done using the left and right arrow keys on the keyboard.

In icon view the template categories are shown on the left side of the window and the templates in each category are shown on the right. The name and location of the new case can be set at the bottom of the window. Use the Browse button to bring up a file dialogue to choose a different location of the case. The default location of new cases can be changed in the Option dialogue. When selecting a template OLGA suggests a default case name based on the template selected and a number if a case with that name already exists. The new case is created by clicking the Create button or double-clicking on the template. The new case will be added to the currently open project. If no project is open, a new project with the same name as the case will be created.

RecentPreviously opened projects and cases can be accessed from the Recent page.

Selecting a recent project will open all cases from that project in separate tabs. Selecting a recent case will open it and add it to the currently open project or create a default project if no project is open.

ToolsThe Tools page is accessed through the File menu.

This page gives access to useful utilities which are installed with OLGA. These tools are documented separately. Other external tools may be added to this page via the Options dialogue. See also Tools available with OLGA

HelpThe Help page is accessed through the File menu.

OLGA Help Wells Help Getting started with OLGA 7 Samples Support Centre Send to support About OLGA

Opens the general user documentation Opens the well GUI documentation Opens a video showing some of the steps to build a case in OLGA 7 Open the folder where the sample cases are stored Link to the SPT Group's support centre on the internet, requires internet access Zips the projects with all cases and data files and attaches it to an e-mail template List the version information

OptionsThe overall simulator settings are specified under Options. The Options dialogue is located under the File menu Settings under the General tab are: o o o o o o My Project Location: Location where file dialogs will open. Specify if the program shall execute auto-save at specified intervals. Delete .bat file after batch simulation Simulation threads number of treads to run simultaneously. By default the number of treads available will be used in an optimal way. Write default values this option will print the default values to the opi file. However, this option should not be used when running the case. There are some limitations and a runnable case will not always be runnable if this option is used. It is useful to use for quality assurance as it shows all inputs used. Restore to Factory Settings: The layout of the GUI windows, default unit set and similar will be restored.

External programs that should be available from the Tools page can be specified under the External Tools tab. Some programs are set by default during installation and additional programs like Excel, a text-editor etc. can be specified. Select Add to browse for an external tool to include in this list.

The Default Units tab is used to select the preferred set of units. Units can select from three predefined sets (SI, Metric and Oilfield) or a customized set may be specified. The default units affects the none given properties and the default values in the property editor and also which units the plotting variables are shown in.

2nd order schemeMass equations can be solved with two different schemes in OLGA. The default is a 1st order scheme (upwind implicit) and the alternative is a 2nd order TVD scheme. The 1st order scheme is more robust and should be the preferred choice in most situations. The 2nd order scheme has less numerical diffusion and therefore keeps holdup fronts better. See also: When to use Methods and assumptions Limitations How to use

When to useThe 2nd order scheme for mass equations is to be used when it is important to track relatively sharp holdup fronts. Examples are: 1. Oil-Water fronts 2. Inhibitor fronts 3. Gas-Oil fronts

Methods and assumptionsThe 2nd order method used for the mass equations is a combination of different numerical schemes in order to get a stable method which satisfies the TVD (Total Variation Diminishing) condition. For smooth gradients the method is 2nd order while for non-smooth flow (shocks) the method reduces to 1st order upstream. The smoothness of the data is measured on the control volume boundary like this

Where m is the mass and is the measure of smoothness. If < 0 the method reduces to first order upstream and if > 0 the method uses 2nd order methods. In the 2nd order region the numerical scheme is determined based on a 2nd order limiter. In OLGA the limiter known as the van Leer limiter is chosen.

Simulation differences between the 1st order and 2nd order schemes

Figure 2 Profile plot of an oilwater front showing the differences between the two schemes. The number of sections in the pipeline are 50, 100 and 500, respectively.

Figure 3 Profile plots of a gasoil front. The number of sections in the pipeline are 50, 100, 200, 500 and 1000, respectively.

Figure 4 Trend plot showing the hold-up at the top of a riser. The number of sections in the riser are 15, 3