塔北三叠、侏罗系孔隙类型及次生孔隙的成因

PORE TYPES AND ORIGIN OF SECONDARY PORES OF TRIASSIC AND JURASSIC IN NORTH TARIM

塔北三叠、侏罗系储层主要发育粒间孔（包括残余原生粒间孔、次生粒间孔和混合粒间孔）、粒内孔、填隙物中微孔隙和缝隙等４类。尤以混合粒间孔最为发育，占总面孔率的４３％～５１％，是储集空间的主要组成部分。干酪根和粘土转化所释放的有机酸对储层中铝硅酸盐组分和部分石英颗粒阴离子的络合迁移作用是次生孔隙形成的主要原因，可净增约９．６％的次生孔隙，即增加的次生孔隙约占总孔隙的５１．９％，表明了次生孔隙在提高储层储集性中的重要作用。储层除受有利相带和储集类型控制外，埋藏深度（以４２００～４７００ｍ最为有利）及由断裂和不整合面构成的输导通道亦是重要控制因素。

Intergranular pores, intragranular pores, micropores in interstitial material and crevicesare developed in Triassic and Jurassic reservoirs in North Tarim region, and the secondaryporosity of mixed intergranular pores, amounting to 43% ￣51% of total pore amount, is themain part of resrevoir spaces. Organic acids released by kerogen and clay mineral transformation affected the alumosilicate component and quartz anions in reservoirs. This is the principle cause for the formation of secondary porosity' The increased secondary porosity is up toabout 51. 9% of the total porosity. Besides, the reservoir property is also controlled by burialdepth, unconformity and the passage formed of 'Y' -type faults.