摘要
山西沁水盆地中、南部下二叠统山西组主煤储层现代构造应力场主应力差增大,煤储层渗透率梯度呈指数形式增长,煤储层压力梯度呈对数增长,这种规律主要受控于现代构造应力场主应力方向与煤储层天然裂隙优势发育方向之间的相互关系。这两组方向对于煤储层来说近于平行,对煤储层顶板则表现为近于正交,由此导致主煤储层中天然裂隙处于相对拉张状态,而其顶板天然裂隙处于挤压状态,主应力差越大,相对拉张(挤压)效应就越显著。基于这种规律和控制机理,预测渗透率大于1md的山西组主煤储层可能分布于盆地内的阳城、潞城与沁源之间地带、武乡与左权之间地带以及左权西北方向的局部地区。
As for the main coal reservoirs of the lower Permian Shanxi Formation in the central-southern Qinshui basin, the permeability gradient of coal reservoirs tends to increase in exponential fanction and the pressure gradient to rise in logarithmic function with the increase of the principal stress difference σ1-σ3 of modern tectonic stress field, which is predominantly controlled by the correlation between the main stress direction and the preferentially developed direction of natural fissures in coal reservoirs. These two directions are nearly parallel for the coal reservoirs but nearly normal for the roof of coal seams. As a result, the natural fissures in coal reservoirs might be in a tensional state whereas those in the roof be in a compressive state. The larger the principal stress difference, the more remarkable the relative tensional or compressive effect. Based upon the regularity or controlling mechanism, it is predicted that the lower Permian main coal reservoirs might occur in Yangcheng, the area between Lucheng and Qinyuan, the area between Wuxiang and Zuoquan and northwestern to Zuoquan in the Qinshui basin.
出处
《地质论评》
CAS
CSCD
北大核心
1999年第6期576-583,共8页
Geological Review
基金
国家自然科学基金(编号49772131)
关键词
煤储层
渗透性
构造应力场
盆地
煤矿床
coal reservoir
permeability
modern tectonic stress field
principal stress difference
