文昌凹陷中深层油气断裂控藏规律及断圈有效性评价  

Medium-deep Fault Controls for the Oil and Gas Accumulation and Fault Trap Effectiveness in the Wenchang Depression

作　　者：范彩伟 李明 陈林 FAN Caiwei;LI Ming;CHEN Lin(CNOOC China Limited,Zhanjiang Branch,Zhanjiang 524057,Guangdong,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《大地构造与成矿学》2025年第2期271-284,共14页Geotectonica et Metallogenia

基　　金：中国海洋石油集团有限公司“十四五”科技重大项目(KJGG2022-0302)资助。

摘　　要：珠江口盆地文昌凹陷是南海西部重要的富烃凹陷之一,剩余油气资源量主要集中在中深层圈闭。本文在分析了烃源岩和优质储层分布规律的基础上,研究断裂活动规律和演化特征,明确不同断裂控源储、控圈、控运的作用,以指导文昌凹陷深层油气勘探。研究结果表明,断裂活动强度差异控制了研究区发育滨浅湖和中深湖两类烃源岩。中深层大型砂体以扇三角洲沉积为主,沿珠三南断裂连片分布。生烃期断裂带附近有机酸的溶蚀改造作用和绿泥石包膜的超压胶结抑制作用共同控制了中深层优质储层的形成。因此,文昌凹陷多期构造运动背景下,珠三南断裂带不同时空的差异分段生长过程控制了源储配置。不整合面、砂体和长期活动断裂的相互配置共同控制了油气向琼海凸起聚集。在这样的成藏背景下,建立的断层封闭性分级评价标准可有效指导下一步油气勘探部署。The Wenchang Depression in the Pearl River Mouth Basin is an important hydrocarbon-rich sag in the western South China Sea,and the remaining oil and gas resources are mainly concentrated in medium-deep traps.To guide deep oil and gas exploration in the Wenchang Depression,this study focused on the activity patterns and evolution characteristics of faults and the roles of different faults in controlling source storage,trapping,and transportation on the basis of analyzing the distribution patterns of hydrocarbon source rocks and high-quality reservoirs.The results indicated that the difference in fault activity intensity controlled the development of two types of hydrocarbon source rocks in the study area:shallow and medium deep lakes.Large sand bodies in the middle and deep layers are distributed in contiguous fan delta sedimentary bodies along the south fault of the Pearl River Delta.The dissolution and transformation of organic acids near the fault zone during the hydrocarbon generation period and the overpressure cementation inhibition of chlorite encapsulation jointly controlled the formation of high-quality reservoirs in the middle and deep layers.Therefore,it can be inferred that the different spatiotemporal and segmented growth processes of the Zhusannan fault zone controlled the source reservoir configuration under the background of multiple tectonic movements in the Wenchang Depression.The mutual configuration of unconformity surfaces,sand bodies,and long-term active faults jointly controlled the oil and gas accumulation toward the Qionghai Uplift.Under such a reservoir formation background,the established evaluation criteria for fault sealing can effectively guide the next steps in oil and gas exploration.

关 键 词：分段生长 烃源岩分布 优质储层 断裂封闭性 输导体系 

分 类 号：P618.130[天文地球—矿床学]