甘泉地区长8段储层特征及油气富集规律  

Internal reservoir characteristics and hydrocarbon enrichment law of Chang 8 member in Ganquan area

作　　者：朱必清 陈世加[1] 雷俊杰[2] 白艳军[2] 尹相东 ZHU Biqing;CHEN Shijia;LEI Junjie;BAI Yanjun;YIN Xiangdong(School of Geoscience&Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Yanchang Oilfield Co.,Ltd.,Xi'an,Shaanxi 710000,China)

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500 [2]延长油田股份有限公司,陕西西安710000

出　　处：《石油地质与工程》2022年第2期15-21,28,共8页Petroleum Geology and Engineering

基　　金：国家自然科学基金“源储间泥/钙质等隔层对陆相致密油(低渗透油藏)成藏控制机理研究”(41872165)。

摘　　要：鄂尔多斯盆地甘泉地区长8油藏为典型的低渗透油藏,但油藏主要分布于长8_(2)亚段。为明确储层特征及对油气富集的影响,利用铸体薄片、扫描电镜、压汞测试和物性资料等对甘泉地区延长组长8段储层特征进行了对比研究。结果表明:甘泉地区长8段储层以长石砂岩为主,岩屑长石砂岩次之;主要发育溶蚀粒间孔和长石溶孔,原生粒间孔在长8_(2)储层内保存相对较好;优质储层受沉积微相和成岩作用的控制。与长8_(1)储层相比,长8_(2)储层具有高孔隙度、低排驱压力、高进汞饱和度、低退汞效率和孔隙连通性差的特征。油气分布受控于长8段储层的垂向差异和优质储层的平面展布范围,而原生孔隙发育情况是决定油气产量的重要因素。大量油气早期充注高孔储层,晚期因压实作用强烈、次生改造作用较弱,加上沥青封堵,基本滞留于原地,即主要在长8_(2)亚段富集。Chang 8 reservoir in Ganquan area of Ordos Basin is a typical low permeability reservoir,and the reservoir is mainly distributed in Chang 8_(2) member.In order to make clear the reservoir characteristics and its influence on oil and gas enrichment,the internal reservoir characteristics of Chang 8 member in Yanchang formation of Ganquan area were compared by using cast thin section,scanning electron microscope,mercury injection test and physical property data.The results show that Chang 8 reservoir in Ganquan area is mainly of feldspathic sandstone,followed by lithic feldspathic sandstone.Dissolution intergranular pores and feldspar dissolution pores are mainly developed,and the primary intergranular pores are relatively well preserved in Chang 8_(2).High quality reservoirs are controlled by sedimentary microfacies and diagenesis.Compared with Chang 8_(1),Chang 8_(2) reservoir has the characteristics of high porosity,low displacement pressure,high maximum mercury saturation,low mercury removal efficiency and poor pore connectivity.Oil and gas distribution is controlled by the vertical difference of Chang 8 reservoir and the plane distribution range of high-quality reservoirs,while the development of primary pores is an important factor determining oil and gas production.In the early stage,a large amount of oil and gas was filled into the high porosity area.In the late stage,due to strong compaction,weak secondary transformation and asphalt plugging,it was basically retained in place,that is,it was mainly enriched in Chang 8_(2) reservoir.

关 键 词：甘泉地区 长8段 储层特征 主控因素 油气富集规律 

分 类 号：TE122.3[石油与天然气工程—油气勘探]