东濮凹陷潜山致密砂岩储层成岩演化特征

Diagenesis and evolution characteristics of tight sandstone reservoirs of buried hill in Dongpu Depression

高航

GAO Hang

河南省濮阳县自然资源局，河南 濮阳 457100

Bureau of Natural Resources of Puyang County, Henan Province, Puyang 457100, China

利用铸体薄片、阴极发光、扫描电镜、包裹体测温及X衍射分析等实验测试方法，对东濮凹陷上古生界潜山致密砂岩储层的岩石学特征、成岩作用，及其对储层孔隙演化规律的影响进行了研究。结果表明：潜山致密砂岩储层储集空间以次生溶蚀孔隙为主，通过建立孔隙定量演化模式，明确了山西组—太原组含煤储层孔隙演化与石千峰组—上石盒子组储层存在差异；潜山致密砂岩储层成岩演化阶段整体处于中成岩A—B期，石千峰组—上石盒子组储层具有早胶结、晚溶蚀的特点，储层次生孔隙更发育，山西组—太原组含煤储层具有早溶蚀、后压实、晚胶结的特点，成岩过程中储层快速致密。石千峰组—上石盒子组储层早期方解石胶结增加了抗压实能力，为后期溶蚀作用提供物质基础，在总体致密化背景下成为相对有利的油气勘探目标。

The petrologic feature and diagenesis characteristics of the tight sandstone reservoir in the buried hill of the Upper Paleozoic in Dongpu Depression and its influence on the pore evolution law of the reservoir were studied based on the experimental methods of casting slice, cathode luminescence, scanning electric microscope, inclusion temperature measurement and X-ray diffraction analysis. The results show that the tight sandstone reservoir space is mainly secondary dissolution pores. By the establishment of the quantitative evolution model of porosity, it is found that there are differences in pore evolution between coal-bearing reservoir of Shanxi￣Taiyuan Formation and reservoir of Shiqianfeng￣Shangshihezi Formation. The diagenetic evolution stage of the tight sandstone reservoirs in the burried hill was in the middle diagenetic A￣B stage as a whole. Among them, the coal-bearing reservoirs in Shanxi￣Taiyuan Formation are characterized by early dissolution, late compaction and cementation, and rapid compaction. The reservoirs of Shiqianfeng￣Shangshihezi Formation are characterized by early cementation, late dissolution, and secondary porosity. The early calcite cementation of the Shiqianfeng￣Shangshihezi Formation increased the ant-compaction ability, which provides the material basis for the later dissolution, so the reservoir of Shiqianfeng￣Shangshihezi Formation is a relatively favorable oil and gas exploration target under the tight background.

10.6056/dkyqt202103002