油气沿断层走向运移的地质特征及相关问题探讨——以济阳坳陷沾化凹陷邵家断层为例

Geological characteristics of hydrocarbon migration along a strike fault: a case study of Shaojia Fault, Zhanhua Sag, Jiyang Depression

王亚琳

WANG Yalin

中国石化 胜利油田分公司 勘探开发研究院, 山东 东营 257015

Exploration and Development Research Institute, SINOPEC Shengli Oilfield Company, Dongying, Shandong 257015, China

以渤海湾盆地济阳坳陷沾化凹陷邵家洼陷NEE走向的邵家断层为例，总结了油气沿断层发生走向运移的特殊地质条件，包括断层具有走滑性质、断层位于构造脊之上、断层两盘输导层极不发育、充足的油源和沿途欠发育的圈闭以及断层末端与地层中发育的输导层匹配等。以上地质条件在大部分地区都不可能同时具备，这也是断层走向运移现象较为罕见的主要地质原因。为了总结断层走向运移的适用地质条件，又对济阳坳陷发育的不同走向弯曲断层、储层（输导层）发育的地层与断层组合样式等与油气走向运移的关系进行了探讨。分析认为，在新近纪油气主要运移期和成藏期，NW向左行左阶断层、NE向右行右阶断层在弯曲处易形成拉张薄弱带，有利于油气的垂向和走向运移；认为砂体所在地层的等高线与断层间呈现向断层收敛的“羽状”、垂直的“丰”字形以及“半羽—半丰字形”这3种地层与断层的组合样式，油气均无法运移出断层进入地层中的输导层，易于发生油气沿断层的走向运移，并分别建立了相关模式，探讨了东营凹陷石村断层、惠民凹陷临邑断层走向运移油气的可能性。

The ENE trending Shaojia Fault in the Shaojia Subsag, Zhanhua Sag, Jiyang Depression has been studied. We summarized some special geological conditions for hydrocarbon migration along strike faults, including strike slip properties, faults located on a structural ridge, extremely underdeveloped transport layers on both sides of a fault, sufficient oil source and underdeveloped trap, and the matching between fault end and transport layer. The above geological conditions are not likely to be present at the same time in most areas, which explains rare hydrocarbon migration along a strike fault. The relationship between bending faults in different directions, reservior (transport layer) development formation, fault combination pattern and hydrocarbon migration along a strike fault were discussed in order to summarize the favorable geological conditions for hydrocarbon migration. It was concluded that during the main migration and accumulation period in Neogene, NW trending left lateral left-step faults and NE trending right lateral right-step faults were easy to form in a tensile weak zone at the bend, and were favorable for vertical and strike migration of hydrocarbon. The contours of sand bodies presented pinnate shape, vertical "丰" shape and half pinnate and half "丰" shape toward faults. As a result, hydrocarbon could not migrate out of the fault into a carrier bed, but migrates along a strike fault. The possibility of hydrocarbon migration along a strike fault of the Shicun Fault in Dongying Sag and the Linyi Fault in Huimin Sag was discussed.

国家科技重大专项“渤海湾盆地精细勘探关键技术”（三期）子课题“济阳坳陷油气富集机制与增储领域”（2016ZX05006-003）资助。

https://doi.org/10.11781/sysydz201805684