断块油气田2023年1月Highperformanceandenvironment-friendlywater-baseddrillingfluidforshalereservoiranditsenvironmentalimpactassessmentTIANWenxin1,YUHaojie2，3(1.TheOpenUniversityofShaanxi,Xi′an710119,China;2.Drilling＆ProductionEngineeringTechnologyInstituteofCCDC,Xi′an710018,China;3.NationalEngineeringLaboratoryforLow-PermeabilityOil-GasFieldExplorationandDevelopment,Xi′an710018,China)Abstract:Theconventionalwater-baseddrillingfluidusedintightoilhorizontalwellsinOrdosBasincannotmeettherequirementsofdrillingconstruction,andtheuseofoil-baseddrillingfluidwillcauseseriousenvironmentalpollution,whichcannotmeettherequirementsofenvironmentalprotection.Therefore,anhighperformanceandenvironment-friendlywater-baseddrillingfluidsystemsuitablefortightoilhorizontalwellswasdevelopedwithcompositeorganicsaltinhibitorFQYY-1,environment-friendlylubricantHBRH-3andcompositemicronanoantisloughingpluggingagentFAD-35asthemaintreatmentagents.Theresultsshowthatthedrillingfluidsystemhasstablerheologicalpropertiesandlowfiltrationafterrollingagingat140℃for16h.Thesecondrollingrecoveryrateofcuttingsinthereservoirsectionofthetargetblockcanstillreachabout90%,andtheinhibitionperformanceisstrong.Thedrillingfluidsystemhasastrongpluggingabilityfor1￣100μmcorefractures,andthefinalcumulativefiltrationislessthan3.0mL.Theextremepressurelubricationcoefficientandmudcakeadhesioncoefficientare0.084and0.025respectively,andthelubricationperformanceisequivalenttothatofoil-baseddrillingfluid.Afteradding10%cuttings,10%NaCland1%CaCl2respectivelyintothesystem,therheologicalpropertiesandfiltrationofthedrillingfluidchangelittle,andtheanti-pollutionabilityisstrong.ThebiologicaltoxicityparameterEC50valueofthesystemis84,515mg/L,thebiologicaldegradabilityparameterBOD5/CODcris0.172.Thecontentofheavymetalsislowerthanthestandardrequirements,andtheenvironmentalprotectionperformanceisgood.ThedrillingfluidsystemwasusedinthethirdhorizontalsectionofwellS4029.Thedrillingprocesswassmooth,thedrillingfluidper-formancewasstabl...
