川西坳陷孝泉-丰谷构造带须家河组气藏成藏机制研究

FORMATION MECHANISM OF GAS RESERVOIR IN THE UPPER TRIASSIC XUJIAHE FORMATION ALONG THE XIAOQUAN-FENGGU SAG BELT, WESTERN SICHUAN

据彭县须家河组地表剖面、岩芯观察和常规物性、压汞参数、铸体薄片等测试资料 ,统计约 2 0 0 0多个数据及油气显示资料 ,确认该区天然气属非常规致密储层气藏领域。针对成藏条件较为复杂和气藏特征零乱的特点 ,对储集、圈闭条件在油气生成、运移、聚集和保存等过程中相互配置的独特成藏机制进行了初步研究。须家河组气藏属于高压 -超高压气藏 ;气藏发育在油气主要生成期时运移条件良好的储集体中 ;须下组合为一具活跃地层水的似层状气藏 ,局部显示不规则特征 ;须上组合则表现为区域上不太规则的非层状储集体 ,局部仍属含水似层状气藏。总体看 ,气藏强烈依赖于裂缝的存在 ;气藏形态不受现今构造形态的严格控制 ;

It is confirmed that natural gas reservoired in the Xujiahe Formation in Peng County is of an irregular compact and condensed reservoir on the bassis of analyzing 2000 geological data and exposure situation of oil gas. All the data and materials are obtained from investigations on cores, and experiments on normal physical properties, intrusive mercury parameters, cast thin sections. This paper is concentrated on studying mechanics of oil gas formation, migration, accumulation, and preservation upon the conditions of reservation and trapping according to more complicated and disordered gas reservoirs. It indicates proposes that gas pools in the Xujiahe Formation are preserved in well migrated reservoirs with high and super pressures, in which quasi layered gas pools with a little irregularity under the condition of active formation water are developed in the lower Xujiahe Formation, and the regional non layered and limited quasi layered ones in the upper. As a whole, how the gas reservoirs are preserved is extremely depended on fractures, but the shape of the gas reservoir is independent on a structure belt and the gas content in the main reservoir is a positive correlation with the development of sand bodies.