东濮凹陷前梨园洼陷南部深盆气有利目标评价

Evaluation of Favorable Targets for Deep-basin Gas in the Southern Qianliyuan Sub-sag in Dongpu Sag

依据烃源岩品质、盐岩分布以及烃源岩热演化程度的分析,认为东濮凹陷沙三下亚段是深盆气有利勘探区面积最大的区域,为深盆气风险勘探的首选层系。根据储集条件、盖层与保存条件优选勘探区带。前梨园洼陷南部沙三下亚段可细分为两套储盖组合,其特点在于断层较少、封堵性良好,被选定为深盆气的勘探区带。针对前梨园洼陷南部沙三下亚段的3砂组、5砂组、6砂组和7砂组这四套湖底扇储层,采用井控拓频技术以提高砂体纵向分辨能力。在优选勘探目标时,优选杜寨断层下降盘靠近物源区、储层厚度最大的构造-岩性圈闭进行风险勘探。这一策略为东濮老区天然气增储建产接替阵地指明了明确的方向。

According to the analysis of hydrocarbon source rock quality,salt rock distribution,and the thermal evolution degree of hydrocarbon source rocks,it is concluded that the lower sub-segment of the third member of Shahe Formation in Dongpu sag is the largest favorable exploration area for deep-basin gas,making it the preferred stratum for deep-basin gas risk exploration.The exploration target areas are optimized based on reservoir conditions,caprocks,and preservation conditions.The southern part of Qianliyuan sag in the lower sub-segment of the third member of Shahe Formation can be subdivided into two sets of reservoir-caprock combinations,characterized by fewer faults and good sealing properties,and is selected as the exploration target area for deep-basin gas.For the four sets of lacustrine fan reservoirs,including the 3rd,5th,6th,and 7th sand groups in the southern part of Qianliyuan sag in the lower sub-segment of the third member of Shahe Formation,well-controlled frequency expansion technology is used to improve the vertical resolution of sand bodies.In the selection of exploration targets,structural-lithologic traps with the largest reservoir thickness in the descending plate of Duzhai fault near the source area are preferred for risk exploration.This strategy provides a clear direction for the replacement of natural gas reserve increase and production establishment in the old Dongpu area.