川东南平桥地区寒武系洗象池群断层流体溶蚀-沉淀作用对白云岩储层的影响  

The influence of dissolution-precipitation driven by fault-transported fluids on the development of dolostone reservoirs in the Cambrian Xixiangchi Group at Pingqiao area of the eastern Sichuan basin

作　　者：刘晨虎 杨明磊 诸丹诚 杨伟强 陈凡卓 邹华耀[1,2] LIU Chenhu;YANG Minglei;ZHU Dancheng;YANG Weiqiang;CHEN Fanzhuo;ZOU Huayao(College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum,Beijing 102249,China;China Zhenhua Oil Co.,Ltd.,Beijing 102249,China;Exploration and Development Research Institute,Zhongyuan Oilfield Company,SINOPEC,Puyang 457001,China)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [3]振华石油控股有限公司,北京100031 [4]中国石化中原油田分公司勘探开发研究院,河南濮阳457001

出　　处：《地质学报》2025年第3期865-878,共14页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42172125)资助的成果。

摘　　要：含膏盐白云岩储层非均质性是优质白云岩储层形成的关键问题之一。本研究利用岩芯、薄片、测井、包裹体、物性等资料,深入探讨川东南平桥地区洗象池群储层中石膏和方解石充填物对储层非均质性的影响,定量表征胶结物的发育分布特征,分析胶结物的成因,半定量恢复储层孔隙差异演化过程。结果表明:①虽然PQ2井裂缝相对PQ1井较为发育,但裂缝和孔洞中的充填物含量相对较高,裂缝对储层物性改造相对较差。②石膏胶结物来源于下伏高台组含膏流体,早白垩世断层形成时期,高温高压条件下富含SO_(4)^(2-)的高台组地层水上涌与富含Ca^(2+)、Mg^(2+)、CO_(3)^(2-)的洗象池群地层水混合,在同离子效应和地层抬升导致的降温条件下,发生方解石和石膏沉淀。③断层流体胶结物充填的颗粒白云岩和残余孔隙的颗粒白云岩在燕山期构造运动之前孔隙演化相似,即准同生期大气淡水溶蚀形成溶蚀孔洞,淡水和海水胶结作用以及压实压溶作用破坏孔隙;但在燕山期—喜马拉雅期发育的逆断层的影响下,流体混合溶蚀-沉淀作用优先发生在断层附近的颗粒白云岩,造成孔隙差异演化。The heterogeneity of gypsum-bearing dolomitized reservoirs is a crucial issue in understanding their formation mechanisms.This study,employing a multidisciplinary approach encompassing petrographic,geophysical,and geochemical analyses,investigates the influence of gypsum and calcite fill cements on the quality of these reservoirs.Through the examination of porosity distribution,origin,and semi-quantitative reconstruction,several key findings emerged.Firstly,calcite cements and gypsum have completely filled fractures and vugslocated in close proximity to fault zones.This extensive infilling process has resulted in significantly reduced porosity and permeability in the carbonate rocks adjacent to these fractures.Secondly,the fluid responsible for gypsum precipitation originated from the underlying Gaotai Formation,characterized by gypsum-rich carbonate successions.This precipitation was induced by the mixing of sulfate-,calcium-,and magnesium-rich fluids under high temperature and pressure conditions.Finally,the diagenetic parasequence preceding the Yanshan tectonic movement exhibits comparable characteristics,while the faults induced by thrust tectonic during the Yanshan-Himalayan tectonic event significantly controlled the differential evolution of porosity in the dolomitized reservoirs.

关 键 词：断层流体 石膏胶结 白云岩储层 洗象池群 四川盆地 

分 类 号：P61[天文地球—矿床学]