鄂尔多斯盆地延安地区致密砂岩气藏“甜点”储层主控因素分析  

Major Controlling Factor of Tight Sandstone Gas Sweat Reservoir in Yan′an Area of Ordos Basin

作　　者：杨希濮 孙卫[2,3] 

机构地区：[1]中海油研究总院,北京100028 [2]西北大学地质学系,西安710069 [3]西北大学大陆动力学国家重点实验室,西安710069

出　　处：《地质科技情报》2016年第6期138-143,共6页Geological Science and Technology Information

基　　金：国家科技支撑计划项目"低(超低)渗透油田高效增产改造和提高采收率技术与产业化示范"(2007BAB17B00)

摘　　要：通过物性分析、薄片分析、扫描电镜、压汞、核磁共振等多种方法相结合,对鄂尔多斯盆地延安地区致密砂岩气藏的孔隙结构进行了微观、定量分析。结果表明:山二段储层孔隙结构明显优于盒八段,山二段以粒间孔和溶孔为主,占总孔隙的77%,喉道较大,平均喉道半径为0.6μm,孔喉连通性较好;盒八段晶间孔相对较多,占总孔隙的32%,喉道较小,平均喉道半径为0.3μm,连通性较差。在此基础上对"甜点"储层主控因素进行了分析,研究表明:沉积与成岩作用的耦合是"甜点"储层的主控因素,主导储层空间展布和孔隙演化;沉积优势相带中,石英等刚性矿物含量高、填隙物含量少,导致储层在成岩过程中压实、胶结、杂质蚀变等破坏性作用减弱,溶蚀等建设性作用增强,促使孔隙结构向有利方向演化。This paper analizes quantitatively the micro-pore structure characteristics of tight sandstone gas reservoir in Yan＇an area by means of the physical property analysis , thin section analysis, scanning electron microscope, high pressure Hg injection and nuclear magnetic resonance. The result shows that the micro-pore structure charac- teristics of Shan 2 Member reservoir are better than those of He 8 Member. The main pore types of Shan 2 Member reservoir are intergranular pore and dissolved pore, with the content 77%. The throat of sweat reservoir is large, with an average throat radius 0.6 tam, and the pore connectivity is good. However, the intercrystal pore in He 8 Member reservoir is more, with the content 32%, and the throat is small, with an average throat radius 0.3 μm, the pore connectivity is poor. The research shows that the sweat reservoir distribution and pore evolution are controlled by coupling of sedimentation and diagenesis. Favorable reservoir is general in the place, with the existence of underwater distributary channel microfacies. The hight content of quartz and the low content of plastic components in this area cause the decrease of the compaction, carbonate cementation and matrix dissolution and the increase of dissolution accordingly, which finally lead the pore structure evolution towards a favorable direction.

关 键 词：致密砂岩气藏 孔隙结构特征 二叠系 山二段 盒八段 

分 类 号：P618.130.21[天文地球—矿床学]