西昌盆地中部上三叠统白果湾组页岩地球化学特征及评价

Cemical characteristics and evaluation of shale of Upper Triassic Baiguowan Formation in central Xichang Basin

西昌盆地页岩气研究基础薄弱,本文以西昌盆地中部上三叠统白果湾组为例,结合地球化学特征,对其生烃条件与储集条件进行了研究。结果表明研究区白果湾组发育滨浅湖相、浅湖相两类有利陆相页岩气发育的相带。研究区富有机质页岩厚度普遍大于40m,主要分布在白果湾组在下部与中部。有机质类型以II2型为主,有机质丰度丰度值普遍大于1%,有机质成熟度主体大于2.25%、是大量生产干气的阶段。孔隙度主要分布在5.27~7.26%之间,渗透率普遍大于800nd。脆性矿物平均含量在65%,黏矿物平均含量为35%。研究区白果湾组页岩厚度、有机质丰度、成熟度、孔隙度、渗透率、脆性矿物含量、黏矿物含量均符合中国陆上页岩气有利层段/区确定条件与下限标准,具有较好的页岩气勘探前景。

Shale gas research in Xichang Basin is weak.This paper takes the Upper Triassic Baiguowan Formation in central Xichang Basin as an example and combines geochemistryHydrocarbon generation and storage conditions were studied.The results show that there are two types of shore and shallow lake facies in The Baiguowan FormationFacies belt of continental shale gas development.The thickness of organic-rich shale in the study area is generally greater than 40m,which is mainly distributed in the lower and middle part of The Baiguowan Formation.There areThe average abundance of organic matter is generally greater than 1%.The main body of organic matter maturity is greater than 2.25%The phase of qi.The porosity is mainly distributed between 5.27 and 7.26%,and the permeability is generally greater than 800nd.Average content of brittle minerals in 65%,clay oreThe average content was 35%.Shale thickness,organic matter abundance,maturity,porosity,permeability,brittle mineral content,The contents of clay minerals are in line with the determination conditions and lower limit standards of favorable shale gas intervals/areas in Onshore China,and have a good prospect for shale gas exploration.