川西南部地区沙溪庙组沉积成岩特征与储层关系研究  

RESEARCH ON SEDIMENTATION DIAGENETIC FEATURE AND RESERVOIR RELATIONSHIP OF SAXIMIAO FORMATION IN SOUTH DISTRICT OF WEST SICHUAN 1)

作　　者：蔡开平[1] 樊世海[1] 张本健[1] 杨华[1] 周玲[1] 

机构地区：[1]中油西南油气田分公司川西北气矿

出　　处：《天然气勘探与开发》2004年第3期11-17,共7页Natural Gas Exploration and Development

基　　金：西南油气田分公司科研课题 ( 2 0 0 2 0 3 0 2 -0 2 -0 2 ;川西南部地区沙溪庙组勘探目标评选研究 )部分内容

摘　　要：工区东、西两边沙溪庙组具不同的物源沉积 ,表现在长石含量、碳酸盐岩屑和砂体旋回分布上。方解石胶结是砂岩储层最重要的一种成岩作用 ,非常发育和广泛。在高长石含量砂岩段能见到较多的自生绿泥石充填粒间 ,常成为砂岩的主要胶结物。碎屑的溶蚀以长石为主 ,其它碎屑次之。本区主要有两种重要成岩相 ,即绿泥石—硅质—早期方解石—晚期方解石、早期方解石—硅质—晚期方解石成岩序列 ,前者对勘探有利 ,它多发生于长石含量较高的砂岩中。不同的成岩相导致各构造砂体不同的成岩强度和孔隙组合类型 ,从而使砂岩的储集性能有较大区别。孔隙与砂岩组构密切相关 ,孔隙更容易产生于长石含量高 (>37% )、且胶结物含量低 (碳酸盐 <5 % )的中粒砂岩中。对沙溪庙组的油气勘探 ,应优先寻找那些厚度≥ 5m的细—中粒高长石含量砂岩。当储层裂缝发育时 ,对岩性和砂体厚度的要求相对放宽。There are different sediment origins for Saximiao formation on both east and west sides of work area, shown in the distribution of feldspar content, carbonate rock cuttings and sandbody cycle. Calcite cementation is one of the most important diagenesis in sandstone reservoir, extraordinarily growing and widespread. More autogenic chlorite, always becoming the main cements of sandstone, fill inter grains, capably seen in sandstone interval of high feldspar content. Clastic corrosion is mainly feldspar with other clastics secondarily. There are mainly 2 important diagenetic facies in this area, i.e., the diagenetic sequences as: chlorite--siliceous matter--early calcite--late calcite, and early calcite--siliceous matter--late calcite, with the former beneficial to exploration, which mostly takes place in sandstone containing more feldspar. Different diagenetic facies leads to different diagenetic intensity and pore combination type of various structural sandbodies, thus making sandstone reservoiring performances more different. Pores are closely correlated with sandstone fabric, and are more easily generated in medium grained sandstone where feldspar content is high(>37%) and cement content is low(carbonate<50%). For oil and gas exploration in Saximiao formation, those fine-to medium-grained sandstones with high content of feldspar and thickness≥5m should be priorily sought. When reservoir fractures are more growing, requirement to lithology and sandbody thickness may be relatively relaxed.

关 键 词：砂岩 沉积成岩 长石 砂体 成岩相 川西 硅质 胶结物 储层 岩屑 

分 类 号：P618.13[天文地球—矿床学]