[email protected] + 44 (0 ... · Prosper analysis on some drilling alternatives but, as...
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www.infinity-limited.com [email protected] + 44 (0) 1224 900 009 Infinity: Engineering Division: Field Development Client: Confidential E&P Project: Flow Assurance Optimisation Background The client had experienced a range of slugging predictions from the reservoir and completions analysis had been performed in GAP Prosper software. Infinity were engaged to verify the results using a three-phase simulator including a holistic analysis to the system. Recommendations on the associated slugging mitigation and management were made. This was done through modelling changes in subsea line size and considering operational alternatives. Challenge The client has previously performed a Prosper analysis on some drilling alternatives but, as Prosper models only run steady state, this would not show the impact during operations. As such, Infinity undertook a more comprehensive study using the multiphase hydrodynamic simulator OLGA to investigate the behaviour of the fluid under transient conditions. From a flow assurance stability perspective, smaller tubing could potentially reduce the pressure fluctuations currently observed at the well tubing in the wells. These fluctuations would typically be translated into slugging issues at the separator that could result in large surges of liquid typically responsible for high-level trips at the topsides separators. Solution In later life of well, or when the wells were operating with lower gas lift injection rates, at water cuts above 50% there were significant advantages with the single string arrangement. These included reducing pressure fluctuations at the tubing and slugging potential. An overall production loss between 25% and 39% was identified for the cases using one of the single string completions for early and mid-life of well. After discussions with the client this option was not identified as a disadvantage. This was due to the completely different business models adjacent to each case. It would represent a deferral economic exercise that would have to be analysed in a broad spectrum of scenarios. These include: • possible flow stability advantages of the smaller tubing and its impact on topsides facilities uptime • production reliability • reduced gas lift injection requirements translated into increase gas export values • cost savings directly related to the drilling operations etc The study is currently being used to review the client’s approach to field development and short-term drilling plans. It is also being expanded to provide production optimisation strategies to currently producing wells.
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Infinity: EngineeringDivision: FieldDevelopmentClient: ConfidentialE&PProject: FlowAssuranceOptimisation
BackgroundThe client had experienced a range ofslugging predictions from the reservoir andcompletionsanalysishadbeenperformed inGAPProspersoftware.Infinitywereengagedto verify the results using a three-phasesimulator including a holistic analysis to thesystem.Recommendationsontheassociatedslugging mitigation and management weremade. This was done through modellingchanges in subsea line size and consideringoperationalalternatives.
ChallengeThe client has previously performed aProsperanalysisonsomedrillingalternativesbut,asProspermodelsonlyrunsteadystate,this would not show the impact duringoperations. As such, Infinity undertook amore comprehensive study using themultiphasehydrodynamicsimulatorOLGAtoinvestigate the behaviour of the fluid undertransient conditions. From a flow assurancestability perspective, smaller tubing couldpotentially reduce the pressure fluctuationscurrently observed at thewell tubing in thewells. These fluctuations would typically betranslated into slugging issues at theseparatorthatcouldresult in largesurgesofliquidtypicallyresponsibleforhigh-leveltripsatthetopsidesseparators.
SolutionIn later life ofwell, orwhen thewellswereoperatingwith lower gas lift injection rates,at water cuts above 50% there weresignificant advantages with the single stringarrangement. These included reducingpressure fluctuations at the tubing andsluggingpotential.
Anoverallproductionlossbetween25%and39%wasidentifiedforthecasesusingoneofthe single string completions for early andmid-life of well. After discussions with theclient this option was not identified as adisadvantage.Thiswasduetothecompletelydifferent business models adjacent to eachcase.Itwouldrepresentadeferraleconomicexercisethatwouldhavetobeanalysedinabroadspectrumofscenarios.Theseinclude:• possible flowstabilityadvantagesof the
smallertubinganditsimpactontopsidesfacilitiesuptime
• productionreliability• reduced gas lift injection requirements
translated into increase gas exportvalues
• cost savings directly related to thedrillingoperationsetc
Thestudyiscurrentlybeingusedtoreviewtheclient’sapproachtofielddevelopmentandshort-termdrillingplans.Itisalsobeingexpandedtoprovideproductionoptimisationstrategiestocurrentlyproducingwells.
