挪威海德罗公司油气井完整性

Well Integrity within Norsk HydroObjective●Develop a consistent procedure formanagement of annular leaks●Risk based approach●Routines for early detection and how tohandle the leaks●Procedure made in collaboration betweenNH, Exprosoft and Kåre Kopren(PTG)●Key items in the procedure:●Include detection, diagnosis, assessment and responses to well annular leaks●No increase in installation risk (QRA modelling)●Specific risk reduction measures●Variations in risk level (subsea vs. topside, gas vs. oil, etc.)●Applicable to all well types operated by Norsk Hydro●In compliance with regulations and standardsPrinciples●Overview of well data and limitations shall follow the well throughout the lifetime●All leaks shall trigger an internal deviation (synergi) –verification in B&B●Well data shall be updated when a leak is detected●Checkout of integrity of next casing●Test program to identify leak above or below BSV, surface pressure after stabilizing of pressure, leak rate●Update of well risk level, based on Wellmaster database●Update of operational proceduresWOCSTo The Cutting's Disposal SystemAMV AVV ACVBMVAWVXOV SIV SITPMBSProductionScale Inhibitor MethanolFlow -line connectorPCVPWV SCVPMVPSliding sleeveFlow control valvesRetrievabl e isolation packerSide mounted gunsGas cap gas lift screen and gas lift valvePressure gauge DHSVRetrievableproduction packerClean out valveScreen with ECP andradioactive tracerStatus procedure for management of well annular leaks●Procedure is finishedRemains:●Implementation●Training of offshore personnel to detect leakages + diagnostic work● A pilot course has been held in april.●Standard course package will be developed based on the experiencefrom the pilot course●All personell involved in detection and diagnostic work offshore andonshore will be invitedHistorical Norsk Hydro downhole annulus well integrity (WI) issues by fieldNote: Based on Norsk Hydro WellMaster phase V data (Snorre and Visund currently Statoil), last major database update April 2004Figure shows “Cumulative #Annulus WI Issues / Cumulative #Completions” by YearField 1995199619971998199920002001200220032004BORG 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %BRAGE0.0 %0.0 %7.4 %9.7 %17.6 %60.4 %57.9 %54.7 %60.0 %59.1 %FRAM VEST 0.0 %0.0 %0.0 %GRANE 0.0 %0.0 %12.5 %NJORD0.0 %0.0 %16.7 %12.5 %35.3 %44.4 %47.4 %47.4 %OSEBERG B 2.9 % 2.6 % 2.3 % 2.0 % 1.9 % 1.8 % 6.6 %8.1 %7.5 %7.4 %OSEBERG C 0.0 %0.0 %0.0 % 3.0 % 6.1 % 6.1 % 5.4 % 5.0 %5.0 % 5.0 %OSEBERG S 豏0.0 %0.0 %9.1 %14.3 %11.1 %10.5 %OSEBERG VEST 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %OSEBERG 豐T 75.0 %27.3 %20.0 %21.1 %25.0 %25.0 %SNORRE 0.0 %0.0 %1.6 %1.5 %2.6 %3.5 %7.5 %8.1 %8.1 %8.1 %SNORRE B 0.0 %0.0 %0.0 %0.0 %TOGP 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %TORDIS 0.0 %14.3 %14.3 %12.5 %11.1 %11.1 %10.0 %10.0 %10.0 %10.0 %TWOP 0.0 %0.0 %0.0 %0.0 % 4.2 %8.0 %7.7 %39.3 %39.3 %37.9 %VARG 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %VIGDIS 0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %0.0 %VISUND 0.0 %0.0 %0.0 %0.0 %0.0 %10.0 %10.0 %10.0 %Total0.7 %1.1 %2.5 %3.0 % 6.3 %12.4 %14.6 %16.7 %16.9 %17.0 %0.0 %5.0 %10.0 %15.0 %20.0 %1995199619971998199920002001200220032004Task Force : Well leaks -Root Cause AnalysisJ. Abdollahi SintefBest practice ISO test Wear testingDope-free connectionTommy LangnesOCTGWear testing Geir Ove HaugenDrill pipeDiagnosis Packer design Safety factors Best practice Course DatabaseBarrier test procedureHilde B. Haga Completion designWear testing Material selection Tore R Andersen Material technologyDiagnosis Course ProceduresThorvald Jakbsen Prod. technologyInge M. CarlsenSintefReference group : Bj ørn Engedal (leader), Nils Romslo, Geir Slora, Eli Tenold, Bjarne Syrstad, Torbj ørn Øvreb ø, Siamos AnastasiosOngoing work: Well Integrity Management System (WIMS)●New database to be developed until 2007●JIP managed by Exprosoft with Hydro, Statoil and Total asparticipants.● A development based on the procedure for management of wellannular leaks●Purpose:● A uniform and structured approach for handling of well integrity duringthe lifetime of a well.●All information available through one system● A clear indication of the well barrier status at all timesWell Integrity Management System (WIMS)●WellMaster software used as a basis –additional applications to bedeveloped●Important functionalities:●Visualising the well barriers and well barrier elements (WBE) throughuse of barrier diagrams and barrier sketches●Identify the functions and and requirements that the well and eachWBE should fulfil●Present the status/condition of each WBE (leak, erosion, etc.)●Keep record of performed tests and results of tests●Keep record of diagnosis results when deviations are identified●Keep record of changes in well integrity and resulting corrective actions●Overview of well risk status●Structured / uniform approach to analyze and evaluate riskRisk based procedure for management of well annular leaksRationale for risk based approach●Reflect variations in actual well risk level●Subsea, topside●Gas, oil, water●Etc.●In principle no tubing and casing leaks accepted by the PSA●”to be on the safe side” –leak(s) will affect the operational risk ina negative wayHowever;●Regulations and NORSOK D-010 open for risk assessment●Departure normally granted by submission of supporting riskanalysis results●Must incorporate principle of ”risk reduction” –risk should not besignificantly higher as a result of the deviationProcedure outline●Procedure split in three main tasks(guidelines):1. Detection and diagnosis2. Evaluation3. Implementation and follow-up●Main results●Extensive diagnosis part●Risk assessment method–Specific risk acceptance criteria–Extensive use of quantitative riskanalysis (fault tree analysis withWellMaster data as input)–Specific risk reduction measures●Documentation of processWell normaloperationCompare AcceptancecriteriaAnnuluspressurelimitsDiagnosisRisk and responseevaluationImplementation andfollow-upTask 1; Detection and diagnosis ●Collection of basic well data (preparatory)●Well schematic, P-tests/FIT/LOT, annuluscapabilities (as well barrier), annular volumes,fluid densities, etc.●When is it needed to assess if there is a leak?●Establish Max operational A-annulus pressure(MOASP) = default bleed off alarm limit●Establish pressure domain for initiation ofdiagnosis activities●“External factors” diagnosis●Abnormal pressure readings may not beattributed to downhole failure/degradation●“Internal factors” diagnosis”●The potential leak rate to the wellheadsurroundings (if blowout through leak path)●Amount of hydrocarbon influx to the annulus●Leak location (depth and relative to well barriers)●Leak failure cause (deterioration/escalationpotential)●Leak directionsWell normaloperationCompare AnnuluspressurelimitsDiagnosis Well designMonitoringLeak location(P vs. TVD)and leak rateestimation toolsprovidedTask 2; Risk assessment and response evaluationAcceptance criteria Risk and responseevaluation Implementation andfollow-up●Risk assessment stepwise covers several risk factors● A risk status code (RSC) is assigned to the well ineach step●Most severe RSC determines the RSC for the well●The well RSC determines a set of actions/risk reducingmeasures to be implemented -Each risk factor have specificrisk factor acceptance criteria●Risk factor acceptance criteria basis:●No risk increase on installation level (as modelled in QRA)●Quantitative analysis performed for a representative ”library” of well types inorder to measure relative increase in leakage risk and effect of risk reducing measures●Rule based/deterministic acceptance criteria (based on industry practice)–Minimum two well barriers–No leak to surroundings–Allowable hydrocarbon (HC) storage in annuli–Risk of escalation/further detoriation–Change in well kill opportunityTask 2; Well risk status code overviewRSC Well RSC description Well risk acceptance A No downhole leak AcceptableB Degraded well.Small increase in risk (none or only relatedto HC in annuli)Acceptable.Risk can be controlledC Degraded well.High risk increase (e.g. P A above MOASPduring normal operation)Acceptable only if risk factors can be controlled (e.g, reduce P A to below MOASP during normal operation)D Dual barrier philosophy not fulfilled / wellbarriers severely degraded / leak tosurroundingsNot acceptableRA step 1; Risk factor = Look at well barrier leak rate consequences●Leak rate acceptance criteria based on leak sizes reflected in●QRA’s on installation level●API 14B leak rate criteria (SCSSV)●Norsk Hydro risk matrix●Different leak rate acceptance criteria for●Non-natural flowing or Non-hydrocarbon flowing wells vs. Hydrocarbon flowing wellsCriteriaRSC Well barrier leak rate lower than acceptance criterion (not considered a failed barrier)B Leak (any size) to a volume not enveloped by qualified well barriersDRA step 2; Risk factor = Relative change in blowout probability –example●Risk status codes based on calculated blowout probability and risk reduction potential assigned to●Surface and subsea wells●Conventional wells (applies to production and injection wells) and gas lift wells●Informative calculations performed for multipurpose well, and gas lift well alternatives with combinations of deep set SCSSV, no SCASSV, annulus tail pipe SCSSV.Interm. Csg. BarrierWell barrier leak rates greater than acceptance criterion (RAC Item no. 5)T/A leak below SCSSVT/A leak above SCSSVA/B leakT/A leak above SCSSV AND A/B leakConventional platform wellNo D C D D YesDCCCRA step 3; Risk factor = Look at well release risk (HC storage -single failure scenario)●Hydrocarbon storage criteria relates to:●For surface wells the quantity of hydrocarbons stored in the well annuli should not be greater than the typical mass of lift gas in the A-annulus above the SCASSV in a gas lift well OR alternatively the max recommended volume stored in other vessels on surface●For subsea wells the release quantity criterion is based on distance to permanent surface installations (rising gas plume) and environmental acceptance criteriaCriteriaRSC The hydrocarbon storage mass in the well annuli is, or may become, greater than the acceptance criterion ORWell annuli fluids are highly toxic (platform well)COtherwiseBRA step 4; Risk factor = Look at leakage cause (well functionality-degradation)●Further escalation that cannot be controlled should not be accepted●If further escalation/degradation of the well can be controlled by given risk reducing measures this can be acceptedCriteriaRSC Material corrosion or erosion is the (most likely) leak cause.D There is, or is a potential for, exposure of equipment toH2S/CO2 levels that are outside design/NACE specifications.ORThere is crossflow (unintended flow) in the well COtherwiseBRA step 5; Risk factor = Look at mechanical/ pressure loads (well functionality –loads/single failure scenario)●Maximum Operational A-annulus Surface Pressure (MOASP) is the limiting wellhead pressure that the A-annulus is deemed safe to be operated under for an extended period of time (years), e.g., for well production.–MOASP = Max known P-integrity of next outer functional annulus (from P-tests, LOT, FIT, recognised field formation fracture gradient data)●Checklist for MTP vs. MOASP provided●If A-annulus pressure can be controlled <= MOASP this can be acceptedCriteriaRSC The maximum potential A-annulus pressure -PA (MTP / A-annulus injection pressure) is greater than MOASP ORMechanical / Pressure loads causing burst/fracture/collapse is the (likely) leak cause COtherwiseBRA step 6; Risk factor = Look at wellkill/recoverability (well functionality –well kill /single failure scenario)If well kill procedures/preparations can be revised and be equally effective as the base case (well with no failure) this can be acceptedCriteriaRSC An additional single well barrier leak situation may affect the ability to efficiently kill the well with mud.C OtherwiseBResponse actions●The resulting Well RSC determines a set of mandatory (M) and alternative(S) remedial actions/risk reducing measures to be implemented●Remedial actions for each RSC based on●Norsk Hydro and industry best practice●The risk assessment (step 1 through 6)RSCABCD Response (illustrative example only)A B C D Revise alarm settings M M M M Increased monitoring M M Increased well barrier testing M S Make plans for well kill M M Immediate intervention to restore twowell barrier envelopes MSummary●Applicable to the well types Norsk Hydro operates●In compliance with regulations and standards for the upstreamsector of the oil industry●Guidelines and worksheets included for detection, diagnosis, andrisk assessment and response to well barrier leaks●Support tools and formulas for diagnosis included●Modular system. Easy to update risk factor acceptance criteria,include additional risk factors, revise risk reduction measures, etc.●Documentation of well “history”●”Library” of relative well leak probabilities -The well leak probabilityfor a wide variety of well types and leak locations are modelled for future referenceQuestions?。