苏北盆地溱潼凹陷沙垛1井侵入岩岩石学特征及其储集性与含油性研究  

Petrological characteristics,reservoir property and oil-bearing potential of intrusive rocks in well

作　　者：夏祥 马晓东[2] 胡文瑄[1] 臧素华[2] XIA Xiang;MA Xiaodong;HU Wenxuan;ZANG Suhua(School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210008,China;SINOPEC East China Oil&Gas Company,Nanjing,Jiangsu 210019,China)

机构地区：[1]南京大学地球科学与工程学院,南京210008 [2]中国石化华东油气分公司,南京210019

出　　处：《石油实验地质》2024年第1期87-97,共11页Petroleum Geology & Experiment

基　　金：中国石化华东油气分公司横向项目“溱潼凹陷辉绿岩形成期次与储集性研究”(34600000-21-ZC0699-0003)资助。

摘　　要：火成岩油气藏逐渐成为重要的油气藏类型,但火成岩储层非均质性很强,储集性能变化很大,储层成因机制研究非常薄弱,成为制约火成岩储层评价的主要瓶颈。以苏北盆地溱潼凹陷古近系阜宁组二段侵入岩为研究对象,通过系统的岩心观察、薄片鉴定、电子探针分析测试和测井解释等,剖析了溱潼凹陷沙垛1井阜二段侵入岩岩性、岩相特征、储层特征和储层发育主控因素。结果表明:该区侵入岩的岩性纵向变化显著,由多期侵入岩叠加组成,顶部为辉绿岩,中部为辉石二长岩,下部为橄榄辉长岩;孔隙发育程度不均一,辉绿岩和辉石二长岩孔隙发育程度低,而橄榄辉长岩孔隙发育程度较高;由于多期侵入作用的叠加以及热液蚀变的改造,发育了较好的储集空间。孔隙类型主要为溶蚀孔和构造裂缝,还发育收缩裂缝。影响储层物性的主要因素是岩性和热液流体活动,其中橄榄辉长岩中辉石等暗色矿物最易蚀变,溶蚀孔发育程度高;此外,区域性的断裂构造在许多致密的火成岩中产生了大量的构造裂缝,有效沟通了侵入岩储层的孔缝系统,且为后期的溶蚀作用提供了岩浆热液流动的通道。沙垛1井钻遇的侵入岩总体上含油性差,下部侵入岩层中可见零星荧光显示,上部侵入岩层中基本不含油。Igneous rock oil and gas reservoir has gradually become an important type of oil and gas reservoir,but the igneous rock reservoir is highly heterogeneous,the reservoir property varies greatly,and the study of reservoir genetic mechanism is unsubstantial,which has become the main bottleneck of igneous rock reservoir evaluation.Taking the intrusive rocks in the second member of Paleogene Funing Formation in the Qintong Sag,Subei Basin as the research object,through systematic core observation,thin section identification,electron probe analysis and testing and logging interpretation,the lithologic and lithofacies characteristics,reservoir characteristics and main controlling factors of reservoir development of the intrusive rocks in the second member of Funing Formation in well Shaduo 1 in the Qintong Sag were analyzed.The results show that the lithology of the intrusive rocks varies remarkably longitudinally,and the intrusive rock body is composed of multiphase intrusive rock,with diabase on the top,pyroxene monzonite in the middle and olivine gabbro at the bottom.The development of porosity varies,with diabase and pyroxene monzonite exhibiting low porosity,while olivine gabbro showing relatively higher porosity.Due to the superimposition of multiple intrusions and hydrothermal alteration,good reservoir spaces are formed,with predominant pore types being dissolution pores and structural fractures,accompanied by the development of shrinkage fractures.The main factors affecting the reservoir physical properties are lithology and hydrothermal fluid activity.Among them,dark minerals such as pyroxene in olivine gabbro are most easily altered,so dissolution pores are highly developed.Additionally,regional fault structures generate numerous structural fractures in many dense igneous rocks,effectively connecting the pore-fracture system of intrusive rock reservoir and providing channels through which magmatic hydrothermal fluids flow in the subsequent dissolution processes.Generally,the overall oil-bearing potential of the

关 键 词：侵入岩储层特征 含油性 阜宁组二段 溱潼凹陷 苏北盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]