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1、第35卷第6期新疆石油地质Vol.35,No.62014年12月XINJIANGPETROLEUMGEOLOGYDec.2014准噶尔盆地玛湖凹陷异常高压分布和形成机理abbb冯冲,姚爱国,汪建富,白雨(中国石油新疆油田分公司,a.博士后工作站;b.勘探开发研究院,新疆克拉玛依834000)摘要:准噶尔盆地玛湖凹陷三叠系及其以下中—深部地层异常高压发育,为分析其形成机理,利用实测地层压力、声波时差和地震等资料,结合沉积和构造背景,借助单井压实曲线分析、单井地层压力预测和盆地模拟技术,研究了玛湖凹陷地层压力的分布特征、成因机理和保存条件
2、。研究表明,玛湖凹陷不同地区超压顶面出现的层位不同,凹陷西北部侏罗系及以上地层多未出现超压,凹陷东南部和达巴松凸起地区侏罗系已经开始出现超压;异常高压的主要成因是快速沉积欠压实作用,生烃增压作用贡献小,凹陷边缘断裂带附近异常高压形成的主要因素是断裂活动引起的他源超高压;三叠纪至今剩余压力演化可以分为4个阶段:无剩余压力段、剩余压力缓慢增加段、剩余压力快速增加段和剩余压力缓慢递减段;玛湖凹陷独特的构造和沉积演化,具备了异常高压流体封存箱的顶板、底板和边板条件,异常高压得以保存至今。关键词:玛湖凹陷;中—深部地层;异常高压;分布规律;成因
3、机理;保存条件文章编号:1001-3873(2014)06-0640-06中图分类号:TE122文献标识码:AAbnormalPressureDistributionandFormationMechanisminMahuSag,JunggarBasinabbbFENGChong,YAOAiguo,WANGJianfu,BAIYu(PetroChinaXinjiangOilfieldCompany,a.PostdoctorWorkstation,b.ResearchInstituteofExplorationandDevelopment
4、,Karamay,Xinjiang834000,China)Abstract:TheTriassicanddeeperformationsinMahusaginJunggarbasinareofabnormalhighpressurewhichisoneoftheimportantfac⁃torcontrollingtheoilandgasaccumulation.Thispaperstudiedthedistribution,originandpreservationconditionoftheabnormalhighpressur
5、eusingmeasuredformationpressure,intervaltransittimeandseismicdata,combinedwiththesedimentaryandtectonicsettingsaswellaswellcompactioncurveandwellpressurepredictionandbasinsimulationtechniques.Theresultshowsthatthetopsurfaceofover⁃pressureappearsindifferentformationsindi
6、fferentareasinMahusag.ItsJurassicandnewerstratamaynothaveoverpressureinnorth⁃westernMahusag,buttheoverpressuresarefoundintheJurassicofsoutheasternMahusagandDabasongswell.Themainformationmech⁃anismoftheabnormalhighpressureisundercompactionduetorapidsedimentation,whilethe
7、contributionfromorganicmaterialmaturingisnotbig.Themajorfactoroftheabnormalhighpressureformationnearthefaultzonesinmarginofthesagattributestotheothersourceoverpressurethatmaycreatefromthefaultactivity.TheresidualpressureevolutionsincetheTriassiccanbedividedintofourstage
8、s:freeresidualpressurestage,slowlyincreasingstageofit,rapidincreasingstageandslowlydecreasingstage.Itistheuniq