蜀南麻柳场地区须家河组致密砂岩成岩作用及相对优质储层形成机理  

Diagenesis and Formation Mechanism of Relatively Quality Reservoir in Tight Sandstone of Xujiahe Formation in Southern Sichuan Basin

作　　者：古娜[1,2] 田景春[1,2] 张翔[1,2] 梁宇晨[2] 苏炳睿[2] 

机构地区：[1]成都理工大学"油气藏地质及开发工程"国家重点实验室,四川成都610059 [2]成都理工大学沉积地质研究院,四川成都610059

出　　处：《四川师范大学学报（自然科学版）》2015年第3期433-441,共9页Journal of Sichuan Normal University（Natural Science）

基　　金：国家自然科学基金(41002032)资助项目

摘　　要：四川盆地南部(蜀南)须家河组砂岩是中国重要的天然气储层和产层,同时也是典型的致密砂岩储层,在其超致密背景下发育有对天然气储集有利的相对优质储层.为有效寻觅并预测致密砂岩中"甜点"储层发育有利区域,运用铸体薄片鉴定、扫描电镜观察,结合物性测试和测井资料对蜀南麻柳场地区须家河组致密砂岩成岩作用类型及相对优质储层形成机理进行了深入研究,结果表明:研究区须家河组致密砂岩经历了压实(压溶)、胶结、溶蚀、交代作用,自生石英、自生方解石、自生绿泥石等自生矿物析出以及破裂作用等多种成岩作用类型;压实作用是储层致密的主要原因;成岩过程中的石英次生加大和钙质胶结是储层致密化的强化与关键;相对优质储层的形成是大地构造背景、沉积环境以及成岩作用等因素在时间和空间上优质组合形成的地质结果,表现在:1)有利的沉积环境造就好的原始组分结构,2)原生孔隙保存条件好,3)成岩中后期的溶蚀作用越强,次生孔隙越发育.自生绿泥石包壳在达到一定厚度后对储层孔隙具有一定的保护作用,尤其是原生粒间孔,在T3x4段较为明显,伴随长石等铝硅酸盐矿物溶解而生成的高岭石规则的晶间孔也提供了一定的储集空间.Tight sandstone of Xujiahe Formation in Southern Sichuan basin （Shunan area） is one of the most important gas reservoir and gas-producing zone in China.Also,it is a typical tight sandstone reservoir.Based on the geological background,super tight sandstone reservoir developed relatively quality reservoir which is good for gas accumulation.For searching and predicting developed areas of ‘ sweet-point’ reservoir effectively,Casting thin sections identify,cathodoluminescence,scanning electron microscope,property measurement and logging data were applied in diagenesis and formation mechanism of relatively quality reservoir in tight sandstone of Xujiahe formation in Shunan Maliuchang area.The results show that the tight sandstone of the Xujiahe formation research area has experienced compaction（pressolution）,cementation,dissolution,metasomatism,authigenic quartz,authigenic calcite,authigenic chlorite,other authigenic mineral precipitation,cataclasis and various types of diagenesis.Compaction is the main reason for the reservoir density.Quartz overgrowth and calcium cementation in the process of diagenesis is the reinforcement and the key of the reservoir densification.Relatively high quality reservoir is formed by tectonic background,sedimentary enviromnent and diagenesis factors shown as follows：1） favorable sedimentary environment; 2） well-preserved condition of primary pore; 3） middle and post-diagenetic dissolution affect promoting the secondary pore development.Authigenic chlorite cladding can protect reservoir porosity when it reaches to a certain thickness,especially for primary intergranular pore which is more obvious in T3x4 segment.Kaolinite rules intergranular hole formed by the feldspar and aluminum silicate mineral dissolving also provide some reservoir space.

关 键 词：成岩作用 相对优质储层 形成机理 须家河组 四川盆地南部 

分 类 号：TE121.1[石油与天然气工程—油气勘探]