沉积、成岩作用对致密储层质量差异的控制——以苏里格气田东区为例

Control effect of deposition and diageneses on quality difference of tight reservoirs: taking reservoirs in Eastern Sulige Gasfield as an example

综合利用实验室岩心分析、沉积相、测井等资料,分析鄂尔多斯盆地苏里格气田东区山1、盒8段致密储层的物性、微观孔隙特征、有效储层厚度及产气能力,对比这2段的储层质量差异,从沉积和成岩角度出发探讨了储层质量差异的原因。辫状河三角洲沉积相背景下的盒8段分流河道砂体岩性粗、厚度大、连通性好,因此储层物性好。相对于盒8段,埋藏更深的山1段具有较高含量的岩屑和塑性矿物,抗压实能力弱,储层原始质量易遭到破坏,且由于受到更强破坏性成岩作用的改造,山1段储层质量更差。

The physical properties,the microscopic pore characteristics,the effective reservoir thickness and the gas production capacity of Shan-1member and He-8 member in the eastern Sulige Gasfield of Ordos Basin are studied according to the integrated analysis of cores,sedimentary facies and logging data,to discuss the reasons leading to the reservoir quality difference between the Shan-1member and the He-8 member from two aspects of sedimentary facies and diagenesis. The distributary channel sandbody of He-8 member with the background of braided river delta sedimentary facies has coarse lithology,big thickness and good connectivity,and therefore its reservoir quality is better than Shan-1 member. By contrast,the Shan-1 member with deeper buried depth has high content of debris and plastic component,which will lead to its weak anti-compaction ability and make its primary reservoir quality be damaged. Meanwhile,the Shan-1 member experienced stronger destructive diageneses. So the reservoir quality of Shan-1 member is worse than that of the He-8 member.