苏里格地区盒_8段储层成岩作用与孔隙演化定量分析

Diagenesis and Quantitative Analysis of Pore Evolution of He_8 Member Reservoir in Sulige Region

针对苏里格地区上古生界盒8段储层整体较为致密以及孔隙度演化复杂的问题,为了确定该区砂岩储层致密的主控因素及规律,综合运用铸体薄片、扫描电镜、X-衍射等资料,采用计点统计法对孔隙度演化进行了定量分析。结果表明:盒_8段储层以岩屑石英砂岩为主,目前已达到中成岩B期。砂岩储层初始孔隙度为38.6%,压实作用使孔隙度降为10.0%,储层已达到致密;而胶结作用又使得孔隙度降至1.2%,加重了其致密程度;但较为发育的溶蚀作用对孔隙度贡献了6.7%,最终达到7.9%,与实测结果误差仅为0.6%,误差在合理范围之内,验证了本次研究方法的可靠性。该方法为该地区同类储层的孔隙演化研究提供了一定指导作用。

Aiming at the problem of being tighter and complex pore evolution of Upper Paleozoic He_8 Member reservoir in the Sulige region,in order to accurately confirm the major controlling factors and regularity of the tightness of sandstone reservoirs in this region,some related data（ casting section,scanning electron microscope,X-diffraction,etc.） was applied to quantitatively analyze pore evolution by counting statistic method. The study result shows that the He_8 Member reservoir is chiefly lithic quartz sandstone,and its current diagenesis has reached middle diagenetic B stag. The initial porosity of the sandstone reservoir was 38. 6%,and was reduced to be 10. 0% by compaction,reaching tight level. Moreover,the porosity was reduced to be 1. 2%,which further enhanced its tightness.However,the relatively developed denudation contributes 6. 7% to porosity to be 7. 9% finally,with only 0. 6% error to the measured data,which is within reasonable error range and proves the reliability of this study method. This method can be used to guide study on pore evolution of similar reservoirs in this region.