OG seminar 10-11 March 2004, Trondheim

Dr.Ing. Program “Multiphase Transport”

Institutt for energi- og prosessteknikkOle.J.Nydal@ntnu.no

• NFR project 144036/211 (KMB) • Participants (2003)

– NFR, Shell, Statoil, Total– NTNU, Dept. Energy and Process Engineering– Laboratories at IFE and SINTEF

• Initially 4 doctorals, currently 6

OG seminar 10-11 March 2004, Trondheim

Research challenges in multiphase transport• Computational tools

– Flow capacity of pipelines; pressure drop and holdup– Dynamics: Unstable flow, transient operations

• Fluid related effects– Solid deposits (gas hydrates, wax, scale, sand) and corrosion

• Equipment– Separation, boosting, metering, control

Transportledninger

Brønner

Stigerør

OG seminar 10-11 March 2004, Trondheim

Computational tools: Background

• Successful Norwegian R&D on computational tools:– SINTEF: Two Phase Flow Laboratory established in 1983– IFE: Transient flow model 1980: OLGA prototype– A series of collaboration projects has resulted in OLGA

becoming international industry standard for transient simulations.Commercialized by Scandpower

• Further tendencies:– Towards 3D simulation– Integrated flow assurance models:

wells / pipe networks / fluid / process / control

OG seminar 10-11 March 2004, Trondheim

PhD program: Objectives

• Provide candidates with expert knowledge on multiphase pipe flow

• Provide results which are relevant and useful for the industry– Experimental data for model verification– Flow models which can be implemented in industrial

simulators

• Make use of multiphase flow laboratories at SINTEF and IFE for fundamental studies– Communication between multiphase laboratories

OG seminar 10-11 March 2004, Trondheim

Organization

Person

Olav Kristiansen Transition

Trygve Wangensteen Model

Monika Johansen Slug flow

George W. Johnson Waves

Fabien Renault Initiation

Jørn Kjølaas Plug

NFR project

2004 20052001 2002 2003

• Coordinator: Ole Jørgen Nydal• Open ended structure: Companies participate with PhD candidates• NFR: candidates or support for extended experimental work• 2 meetings/year (often at company offices)• All multiphase activities are reported into the program (20 persons 2003)

– Doctorals, Post.Doc. students, visitors

OG seminar 10-11 March 2004, Trondheim

Activities

• Important with a combination of experiments and modeling• Experiments

– SINTEF , IFE laboratories can provide data for model tuning– NTNU lab can provide data on transients

• Flow modelling– Mathematical formulation– Numerical methods– Methods of implementation

• Current focus on transient aspects– Gas-oil-water flows

OG seminar 10-11 March 2004, Trondheim

Stor loop SINTEF

Liten loop EPT

Mellomstor loop SINTEF

Mini loop til forelesningerMikro loop (CO2)

Flerfase laboratorier i Trondheim

OG seminar 10-11 March 2004, Trondheim

• Flow of oil-water-air mixtures in pipes• Flow regimes• Pressure drop and phase fractions• Transients: Unstable flows, pigging, riser slugging

• Mini-loop for demonstration / education• NetLab: Internet access to laboratory

• Remote demonstrations, flow studies, courses

Multiphase flow laboratory

Oil-water-air, atmospheric pressure

3, 6 cm. I.D., 14 m length, +- 15 deg. 6 m high, L- and S shaped

Liquid flows 0.02 - 2 m/sAir 0.5 – 30 m/s

Pigging, gas lift, reservoir inlet

Instrumentation: Flow rates, pressure drop, holdup

Manual and automated control

• More informationhttp://www.ept.ntnu.no/MultiphaseOle Jørgen Nydal, NTNUTlf: 73550564Fax: 73593859Ole.J.Nydal@ntnu.no

OG seminar 10-11 March 2004, Trondheim

Student laboratory NTNU

OG seminar 10-11 March 2004, Trondheim

NetLabMultiphase flow laboratory on internet

• Operate multiphase flow laboratory from internet

• Control video camera• Control pumps and valves• Monitor flow in pipe• Record flow rates, pressure and holdup

• Remote access applications• Demonstrations• Courses• Flow studies

• Flow examples• Flow of gas-liquid, oil-water, gas-oil-

water• Flow regimes• Transients

• Collaboration• Cyberlab A/S• HiST

OG seminar 10-11 March 2004, Trondheim

Examples on experiments• Two and three phase flow in S-shaped riser. Stability maps and

slug characteristics• Pigging in S-riser and straight pipe: start-up and flowing conditions• V-shaped geometry: Stop-restart experiments• Stratified-slug transition: hysteresis and effect of pressure• Low liquid loading experiments: three phase flow• Flow with vanishing liquid on the wall: horizontal and vertical• Rising bubbles in large diameter vertical pipes (20, 40 cm)• Bubble velocity in oil-water flow• Oil-water flow in undulating pipes• Oil-water flow in gas lifted wells: flow instabilities

OG seminar 10-11 March 2004, Trondheim

Multiphase Transport: Research tasks

• Olav: Effect of pressure on the transition to slug flow (SINTEF lab)– Field problem: occurrence of initial large slug

• Fabien: Transition models– Flow regime transition criteria, slug initiation modeling

• Monika: Experiments on three phase slug flow – Bubble propagation in oil-water systems

• Trygve: Three phase flow models– Slug tracking with water

• George: Transitional regime between stratified and slug flow– Experiments and flow modeling

• Jørn: Pipeline plugged with gas hydrates– Computational methods for hydrate plug dynamics

OG seminar 10-11 March 2004, Trondheim

Transient pipe flow modelling

• All regimes can be present in a pipeline– Both compressible and incompressible flows

• Classical modelling– Pipeline divided into numerical grid– Conservation equations solved with specific closure laws for each

regime (two fluid or drift flux formulation)

• Slug tracking modelling– Pipeline divided into parts with liquid (slugs) and gas (bubbles)– Incompressible models for liquid parts– Compressible models for gas parts– Object oriented implementation

OG seminar 10-11 March 2004, Trondheim

Control volumes• General model: Slug capture if grid is much smaller than slugs

P, HUmP, H

• OLGA: Sub grid tracking

• Petra: Adaptiv and moving grid on front

P, H P, HUg,Ul

P, H P, HUl

• Sluggit: Grid = slugs and bubbles

OG seminar 10-11 March 2004, Trondheim

0 50 100 150 200 250 300 350 400 4500

0.2

0.4

0.6

0.8Inlet pressure

P (b

ar)

0 50 100 150 200 250 300 350 400 4500

Holdup probe trace at the end of the first riser

0 50 100 150 200 250 300 350 400 4500

Holdup probe trace at the outlet

0.3Pressure drop in the first pipe

0 50 100 150 200 250 300 350 400 4501

1.2

1.4

1.6

1.8x 10

5 Inlet pressure

P (P

a)

0 50 100 150 200 250 300 350 400 450

0

0.2

0.4

0.6

0.8

1

Holdup at the end of the first riser

H (-

)

0 50 100 150 200 250 300 350 400 450

0

0.2

0.4

0.6

0.8

1

Holdup at the outlet

H (-

)

Experiments

Slug tracking simulations

Geometry used in the computations

Geometry of the experimental loop

Terrain slugging in S-riser

OG seminar 10-11 March 2004, Trondheim

Conclusion

• A PhD project on Multiphase Transport has been established, with important support from NFR

• The project has grown 50% during the project period • The project extends beyond the NFR project period, as long as

it maintains industry interest

The project supplies the industry with– Experts within multiphase transport– Support for model improvements: Experimental data and

prototype flow models

• Further development of the program– Incorporate other aspects of flow assurance