Recently, research of continental shale reservoirs physical properties and gas contents become a hot spot.A large sets of continental clastic layers are developed of Xu5 section in Western Sichuan Basin, the gas contents of this shale are good, it has huge shale gas exploration and development potential, but the research degree is shallow now.Based on the situation, by combining with a large number of tests and logging data, a comprehensive study of the physical properties and gas contents of Xu5 section shale have been made.Research results show that Xu5 section shale belong to clay rich siliceous shale facies, it has the similar physical properties with the Fort and Barnett shale in America.The influence factors of shale gas contents include: organic matter content, mineral composition and its content, physical properties and brittleness, gas occurrence state and overpressure.The main reservoir space of Xu5 section shale contain organic matter pores, mineral intercrystal pores and dissolution pores and micro fractures.There has a good positive correlation between shale gas content and the effective porosity and the gas phase permeability.When the clay content in the shale is less than 35%, the gas content and brittleness are both higher;with the increase of clay contents, there is no apparent relationship between the brittleness and shale gas contents.Shale layers that have higher gas contents also have higher gas saturation as well, the adsorption amount of the shale gas contents in Xu5 section is about 60%, indicates that the adsorption state is an important gas occurrence manner in continental shale reservoir.%川西须五段地层发育大套陆相泥页岩夹砂岩层,泥页岩层含气性较好,具有巨大的页岩气勘探开发潜力;但目前研究程度尚浅.基于该现状,结合大量测试及测井资料,对须五段页岩的物理性质及含气性影响因素进行了综合研究.研究结果表明,须五段陆相泥页岩属富黏土硅质泥页岩相,与美国Fort及Barnett地区潜质页岩具有类似的岩石物理性质.影响须五段页岩含气性的影响因素包括:有机质含量、矿物组成及含量、物性、脆性、气体赋存状态及超压.须五段泥页岩的主要储集空间为有机质孔、矿物晶间孔、溶蚀孔及微裂缝.页岩气含气量与有效孔隙度及气相渗透率均具有较好的正相关性.当页岩中黏土含量<35%时,含气性及脆性均较高;随着黏土含量的增加,页岩含气性与脆性间无明显相关性.含气量较高的页岩层具有较高的含气饱和度,须五段陆相泥页岩吸附气含量约占60%,以吸附气为主,表明吸附态是陆相页岩储层中一种重要的气体赋存方式.
展开▼
