石英溶解型次生孔隙的成因及其对储层的影响——以大牛地气田上古生界致密砂岩储层为例

曲希玉; 陈修; 邱隆伟; 张满利; 张向津

doi:10.11743/ogg20150512

层序与储层 | 浏览量 : 0 下载量: 377 CSCD: 0

PDF
导出
分享
收藏
专辑

石英溶解型次生孔隙的成因及其对储层的影响——以大牛地气田上古生界致密砂岩储层为例
Genesis of secondary pore of quartz dissolution type and its influences on reservoir: Taking the tight sandstone reservoir in the Upper Paleozoic of Daniudi gas field as an example
2015年36卷第5期页码：804-813
网络首发：2015-10-28，

纸质出版：2015
DOI： 10.11743/ogg20150512
稿件说明：

移动端阅览

曲希玉, 陈修, 邱隆伟, 等. 石英溶解型次生孔隙的成因及其对储层的影响——以大牛地气田上古生界致密砂岩储层为例[J]. 石油与天然气地质, 2015,36(5):804-813. DOI： 10.11743/ogg20150512.

Qu Xiyu, Chen Xiu, Qiu Longwei, et al. Genesis of secondary pore of quartz dissolution type and its influences on reservoir: Taking the tight sandstone reservoir in the Upper Paleozoic of Daniudi gas field as an example[J]. 2015, 36(5): 804-813. DOI： 10.11743/ogg20150512.

摘要

以鄂尔多斯盆地大牛地气田上古生界致密砂岩储层中的石英溶解为研究对象，借助偏光显微镜、扫描电镜、阴极发光显微镜、激光共聚焦显微镜的观察及统计，结合X-衍射分析数据及水-岩反应实验，总结了石英溶解的典型形貌特征、成因及其对致密砂岩储层的影响。研究结果显示：1）大牛地气田石英溶解现象普遍发育，且具有典型的电镜形貌特征，常呈“雨痕状”与“蜂窝状”的溶蚀坑洞。2）大牛地气田的石英溶解发生于碱性环境下，具体证据为①水热实验证实石英溶解于碱性环境下更易发生，在致密砂岩储层中很难发生酸性溶蚀；②与石英溶解共生的方解石胶结交代现象普遍；③部分层位富伊利石贫高岭石，并发育数量不等的绿泥石包壳。3）石英的碱性溶解作用形成粒间溶蚀孔、扩大孔等次生孔隙，平均増孔近6％，是大牛地气田致密砂岩储层部分层位优质储层的成因。

Abstract

By virtue of polarizing microscope

scanning electron microscope

cathode luminescence microscope

laser scan confocal microscope in combination with X-ray diffraction data and water rock interaction experiment

we studied quartz dissolution in tight sandstone reservoirs in the Upper Paleozoic of Daniudi gas field in Ordos Basin

and summarized the typical morphology features

genesis and its influences on tight sandstone reservoir.Results show that:(1)Quartz dissolution is common and has typical SEM morphology features as “rain print” and “honey comb” solution pits and/or vugs.(2)Quartz dissolution in Daniudigas field develops in alkaline environment

and the detailed evidences are as follows:①hydrothermal experiments verify that quartz dissolves more easily in alkaline environments than in acid conditions;②calcite cementation and metasomatism associated with quartz dissolution are common;③some horizons are rich in illite but poor in kaolinite

with some chlorite coatings occurring sporadically.(3)Quartz alkaline dissolution results in secondary pores such as intergranular dissolution pores and enlarged pores

leading to an average incremental porosity of about 6%.This is the cause of quality reservoirs in some tight sandstone intervals of Daniudi gas field.