S W E L L I N G E L A S T O M E R S

SWELLING ELASTOMERS HAVEbeen a major cost saver through risk mit-igation as well as elimination of cementa-tion and conventional ECPs. In Shell E&P,swelling elastomers have been imple-mented in a number of different uses.These include establishing zonal isola-tion in open hole completions, as a pro-duction separation packer, and as anopen hole clad. In these applications, theelastomers have been run in a variety ofopen hole and casing/tubing sizes.

Approximately 80 deployments havebeen recorded by Shell, all of which weresuccessful. Case examples of each of thethree applications will be presented fromShell operations in the North Sea, theMiddle East, and the Far East.

Deployment of Swelling Elastomers inShell E&P (SPE/IADC 92346) MKleverlaan, A Vos, Shell.

R E M O T E C O N T R O L C E M E N T I N G

Driven by industry trends to deliver realtime solutions as well as the high costs toproduce hydrocarbons from the matureNorth Sea fields, an operator and a serv-ice company worked together to success-fully complete the first fully remote con-trolled offshore cement operation fromonshore. By combining proven technolo-gy with a specific vision for future opera-tions, this next step in propelling theindustry towards the possibility ofremote-driven operations was completedon April 27, 2004.

The authors will detail the vision andbusiness cases behind the onshore oper-ation center, remote controlled cementequipment and movement of cementoperations to the onshore location. It willalso present the benefits of controllingcement operations remotely and onshoreas it pertains to the working environ-ment in the Norwegian sector of theNorth Sea.

Controlling Cement Operations froman Onshore Operation Center(SPE/IADC 92344) B L Allen, JHelgesen, Halliburton; P Tyberoe, BP.

A C I D G A S I N J E C T I O N

Two high rate acid gas injection wellswere drilled in the LaBarge area ofWyoming. These wells were designed forinjection of up to 65 million scf/d of a mix-

ture of 65% H2S and 35% CO2. The tech-nical challenges in well design, casingselection and cementing of the injectionstrings, along with common challengesand operational practices for both wells,will be discussed. Key drivers influencingzonal isolation, salt zone loading, casingand centralizer selection will be present-ed.

The authors will also detail the casingrunning, cement jobs, location problemsencountered, and the steps taken toresolve those problems.

Meeting the Challenges in Design andExecution of Two High Rate Acid GasInjection Wells (SPE/IADC 91861) GBenge, E G Dew, ExxonMobil.

U N D E R B A L A N C E D C E M E N T I N G

The authors will describe unique modeldevelopment, design and operational les-sons with relevance for underbalancedprimary cementing of a 7-in. liner at theNorth Sea Gullfaks field.

Due to very small margins it was desir-able to avoid pressure changes in theopen hole section while circulating thecement.

This was obtained by circulating fluidsout through a choke that was accuratelyregulated to maintain constant bottomhole pressure throughout the circulationphase. The fluids in front of the cementhad relatively low density to compensatefor the high density of the cement, andchoke regulation was crucial before thecement was in place.

A new transient computer model forcement displacement with dynamicchoke regulation was developed to make

it possible to design choke operationsaccurately. No real time downhole pres-sure measurement was performed dur-ing the cementing operation.

The authors will describe the operationin detail with special focus on any unex-pected events. Measured and predictedpressure curves will be shown and ana-lyzed to come up with recommendationson how to carry out similar operationsand how to best carry the technology fur-ther.

Managing Pressures DuringUnderbalanced Cementing by Chokingthe Return Flow: Innovative Designand Operational Modeling as Well asOperational Lessons (SPE/IADC 92568)K S Bjorkevoll, SINTEF; RRommetveit, RF Rogaland Research;J Eck Olsen, A Roenneberg, Statoil.

F O A M E D C E M E N T

One globally used technology in deepwa-ter, foamed cement, has become readilyavailable in Angola. Its use in deepwaterapplications has been shown to simplifywell planning and logistics and hasresulted in increased success and costsavings on current wells.

The authors will discuss the introductionand use of foamed cement in deepwatercementing in Angola, including a discus-sion of logistics associated with foamedcementing, mobilization of crews andequipment, and a comparison of thistechnology against alternate lightweightcement slurries.

The logistics for specialty blendedcements including the need to importspecialty cement materials or blends,excess inventories required to coverlarge contingencies and uncertainties,and associated delivery times will also bediscussed.

An analysis of the introduction of foamedcement to Angola will presented alongwith the associated risks of the use ofboth the foamed cement and alternatespecialty slurries.

On location operational considerationsfor foamed cement and comparisons withmixing of specialty lightweight slurrieswill be outlined.

Use of Foamed Cement in Deep WaterAngola (SPE/IADC 91662-Alternate) GBenge, ExxonMobil. �

40 D R I L L I N G C O N T R A C T O R January/February 2005

Proper cementing technique is key to zonal isolation

The benefits of controlling cement operationsremotely and onshore as it pertains to the work-ing environment in the Norwegian North Seawill be presented. SPE/IADC 92344.

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