秦南凹陷烃源岩特征与油气勘探新领域

Characteristics of source rock and new region of oil and gas exploration in Qinnan Sag

庄新兵 邹华耀 李 楠 杨元元 孙和风

中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249 中海石油（中国）有限公司天津分公司，天津　300452

State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China Tianjin Company, CNOOC, Tianjin 300452, China

2009年钻探凹陷南侧的QHD29-2构造，揭示了千万吨储量的构造岩性复合凝析油气藏。秦南凹陷总体上研究程度比较低，文中从烃源岩有机质地球化学特征、生烃史模拟和油气优势运移路径模拟方面探讨了秦南凹陷勘探潜力和有利区带。秦南凹陷发育3套烃源岩，沙河街烃源岩为好烃源岩，其中沙一段烃源岩具有较强非均质性；东下段烃源岩为中—好烃源岩。油气运移模拟表明：QHD22-2和QHD22-1不在油气运移路径上导致油气贫化；石臼坨凸起油气田应有秦南凹陷的贡献；辽西低凸起南末端和秦南1号断裂的下盘等圈闭为有利勘探区。

In 2009, a complex structural-lithologic condensate oil-gas reservoir with the reserves of ten million tons was discovered when QHD29-2 structure was drilled in the south of Qinnan Sag. As a whole, the study degree was low in the Sag. In this paper, exploration potential and favorable zones prediction are investigated by the discussion of organic matter geochemical behaviors, hydrocarbon generation history simulation and hydrocarbon migration simulation of source rock. The results show that there are three sets of source rocks in the sag. The source rocks of Shahejie Formation are good source rocks and the first member of Shahejie Formation shows a strong heterogeneity. The third member and the lower part of second member of Dongying Formation are middle-good source rocks. Hydrocarbon migration simulation shows that QHD22-2 and QHD22-1 structures are not located in the hydrocarbon migration pathway, resulting in hydrocarbon dilution. The hydrocarbon of Qinnan Sag should migrate into the oil and gas fields of Shijiutuo uplift. The traps, the southern end of Liaoxi low uplift and the footwalls of Qinnan 1 fault, are favorable exploration areas.