盆缘非生烃洼陷它源油气运聚方式及勘探意义——以渤海湾盆地沾化凹陷三合村洼陷为例

盆缘非生烃洼陷的油气勘探受制于较差的油气输导条件，使之往往成为勘探“禁区”。为探索盆缘非生烃洼陷多样化的油气运聚方式，拓展油气勘探空间，以渤海湾盆地沾化凹陷三合村洼陷为例，在系统梳理前人认识基础上，基于钻井、测井、地震及分析测试资料，开展了油气运聚方式分析。结果显示：三合村洼陷存在东营组沉积期和馆陶组-明化镇组沉积期两次油气充注过程，分别对应于早期成藏与中、晚期成藏。早成藏期渤南洼陷与三合村洼陷连为一体，来自渤南洼陷的油气经侧向运聚进入三合村洼陷沙河街组聚集成藏。中、晚成藏期，渤南洼陷生成油气经“网毯”和“不整合体”复合运聚进入三合村洼陷东营组及其以上地层中聚集成藏。盆缘非生烃洼陷油气运聚方式再认识的理论意义在于拓展了油气勘探空间，在现实上发现了三合村油田。

A model of hydrocarbon migration and accumulation in non-hydrocarbon-generating subsag at basin margins and its exploration significance: A case study on Sanhecun subsag of Zhanhua Sag,Bohai Bay Basin

The oil and gas exploration in the non-hydrocarbon-generating subsags at basin margins is usually restricted by relatively poor pathway systems,and often regarded as the "forbidden area" for exploration.In order to examine various hydrocarbon migration and accumulation patterns in non-hydrocarbon-generating subsags at basin margins and expand the realm of hydrocarbon exploration,we have taken the Sanhecun subsag of Zhanhua Sag,Bohai Bay Basin as an example to analyze its hydrocarbon migration and accumulation pattern based on a systematic review of previous knowledge and data including drilling,logging,seismic analysis of Sanhecun subsag of Zhanhua Sag.The results show that Sanhecun subsag has undergone two hydrocarbon charging periods.These are the early-stage hydrocarbon accumulation during the sedimentation of Dongying Formation and the middle-late-stage hydrocarbon accumulation during the sedimentation of Guantao-Minghuazhen Formation.In the early-stage accumulating period,the hydrocarbon-generating Bonan sag was connected to Sanhecun subsag,and hydrocarbon from Bonan sag accumulated in the Shahejie Formation of Sanhecun subsag through lateral migration.In the middle-late-stage accumulating period,through combined migration and accumulation mechanisms of "meshwork-carpet" and "unconformity",hydrocarbon generated in Bonan sag was charged to the Dongying Formation and shallower strata in the Sanhecun sag.The speculation of hydrocarbon migration and accumulation mechanisms in a non-hydrocarbon-generating subsag at basin margins has a theoretical significance by extending hydrocarbon exploration realm,and has led to the discovery of Sanhecun oilfield in practice.