苏76区块上古生界输导体系特征与气藏分布关系

Relationship between characteristics of Upper Paleozoic transport system and gas reservoir distribution in Su 76 block

鄂尔多斯盆地构造稳定,输导体系相对简单,断裂、不整合面等类型的输导体系不甚发育。但作为烃源岩与圈闭之间的“桥梁与纽带”,输导体系在气藏富集规律研究中至关重要。对苏里格气田苏76区块上古生界输导体系进行研究表明:研究区除发育以孔隙为主的输导体系外,还发育以裂缝为主的输导体系。通过分析铸体薄片等岩性资料发现,以孔隙为主的输导体系对平行层面气藏运移起主导作用,而以裂缝为主的输导体系对垂向层面气藏运移起主要作用。应用构造曲率法和R/S分析法对研究区裂缝进行识别,两种方法均与裂缝发育地区有较高的耦合度,且其发育程度与生产情况呈正相关,裂缝越发育,越有利于改善致密储层的输导性能。裂缝的识别与预测,对苏76区块气藏开发具有重要的指导意义。

The Ordos Basin has stable structure,relatively simple transport system,and underdeveloped transport systems such as faults and unconformities.However,as a"bridge and link"between source rock and trap,the transport system is very important in the study of gas reservoir enrichment law.In this paper,the Upper Paleozoic transport system of Su 76 block in Sulige Gas Field is studied.The results show that the transport system mainly composed of pores is developed in the study area,and the transport system mainly composed of fractures is developed.Based on the analysis of cast thin sections and lithology data,the transport system dominated by pores plays a leading role in the migration of parallel layer gas reservoir,while the transport system dominated by fractures plays a leading role in the migration of vertical layer gas reservoir.The structural curvature method and R/S analysis method are used to identify the fractures in the study area.Both methods have a high coupling degree with the fracture development area,and the development degree is positively correlated with the production situation.The more developed the fractures,the more beneficial to improve the transport performance of tight reservoirs.The identification and prediction of fractures is of great guiding significance to the gas reservoir development in Su 76 block.