致密油源储配置特征及油气勘探意义——以四川盆地川中地区侏罗系大安寨段为例

Tight Oil Source-Reservoir Matching Characteristics and Its Significance for Oil and Gas Exploration:A case study of the Jurassic Da’anzhai member in the central Sichuan Basin

为查明源储配置对致密油富集的影响,优选下一步致密油潜在有利区,在岩心和薄片观察的基础上,开展地球化学分析和扫描电镜、微米CT等测试,对川中地区大安寨段烃源岩和致密储层特征进行分析,并通过已知油藏解剖,对大安寨段致密油源储配置类型和平面展布进行了研究,发现源储互层式和上源下储式配置关系最有利于致密油富集。研究结果表明:川中地区大安寨段发育旁生侧旁生侧储储式、源储互层式和上源下储式等3种源储配置,烃源岩为最大湖泛期泥页岩,有机质含量0.54%~2.32%,干酪根类型以腐泥型为主,处于成熟—高成熟阶段;储集空间类型包括溶蚀孔洞和基质孔隙,分别发育于厚层介壳灰岩和中—薄层泥质介壳灰岩中,孔隙度0.38%~6.82%,平均1.67%,渗透率多低于0.1×10^(-3)μm^(2),为特低孔致密储层。现有勘探实践证明油田源储配置关系以源储互层式和上源下储式为主,秋林、仪陇、渠县、李渡和广安地区以该类源储配置关系为主,为下一步致密油潜在有利区。

In order to clarify the influence of source-reservoir matching on the accumulation of tight oil,carrying out the pnext step for otential exploration of tight oil,the geochemical index analysis,scanning electron microscopy,and CT scanning methods were used to analyze the characteristics of the source rock and the tight reservoir characteristics of the Da’anzhai member in the central Sichuan basin.On this basis,the type and plane distribution of the tight oil source-reservoir matching relationship of the Da’anzhai member were studied though the known reservoir anatomy.It was pointed out that the source reservoir interlayer configuration relationship was the most favorable for tight oil enrichment.The results showed that the source reservoir,source reservoir interlayer,upper source reservoir,and compound type were 3 source reservoirs in the Dakai area of the middle Sichuan area.The source rock was the most extensive shale in the largest lake,the organic matter content is 0.54%to 2.32%,the type of kerogen is mainly in the mature and high mature stage,and the type of reservoir space includes the type of storage space.The dissolution pores and matrix pores were developed in the thick layer shell limestone and the medium thin,muddy shell limestone.The porosity was 0.38%to 6.82%,with an average of 1.67%,and the permeability was less than 0.1×10^(-3)μm^(2),which was a tight reservoir of ultra-low porosity.At present,the relationship between the source and reservoir distribution was mainly based on source reservoir interbeds,followed by upper and lower reservoir and compound type.The relationship between source and storage in the autumn forest,Yilong,Quxian,Li Du,and Guang'an areas was favorable for tight oil enrichment,which was the potential exploration field for the next tight oil.