源外地层-岩性油气藏成藏与富集高产主控因素

埕海斜坡区是歧口凹陷重要的“源外”油气勘探区带，尤其是地层-岩性油气藏勘探程度较低，剩余勘探潜力较大。通过对埕海斜坡区古近系地层-岩性油气藏成藏条件的研究表明，该区邻近歧口生烃凹陷，存在多个继承性古沟槽，为砂体输送提供了重要通道，发育2类5种地层-岩性圈闭，储盖组合条件良好，具备地层-岩性油气藏形成的地质条件。研究区与生烃中心存在的源储压差是埕海斜坡区地层-岩性油气藏富集的基础，断层、不整合面和渗透性砂层组成的复式输导体系控制了油气运移方向和聚集方式，沉积微相控制了油气的平面分布。通过地层-岩性油藏特征及分布规律研究，建立埕海斜坡区油气富集成藏模式，明确了北部断阶区主要发育构造-岩性油藏，南部高斜坡区主要发育地层-岩性油藏。

Main controlling factors of hydrocarbon accumulation and enrichment and high yield in stratigraphic-lithological reservoirs outside the source area

Chenghai slope is an important hydrocarbon exploration zone outside the source area in Qikou Sag, characterized with low exploration degree of stratigraphic-lithological reservoir and large residual exploration potential. Through research on the hydrocarbon accumulation conditions of Paleogene lithological reservoirs in Chenghai slope, it is shown that this region is adjacent to Qikou hydrocarbon generation depression, where multiple inherited palaeo-grooves exist to provide an important channel for sand transportation. There are five kinds of lithological traps classified into two types; they have favorable reservoir-cap assemblage conditions and can provide geological conditions for the formation of stratigraphic-lithological reservoirs. The source-reservoir pressure difference exists between the study area and the hydrocarbon generation center, thus providing a basis for stratigraphic lithological reservoir enrichment in Chenghai slope. The compound transport system composed of the faults, unconformities and permeable sand layers can control the hydrocarbon migration direction and accumulation mode, and the plane distribution of oil and gas is controlled by sedimentary micro-facies. By studying the characteristics and distribution laws of stratigraphic-lithological reservoirs, the hydrocarbon accumulation mode in Chenghai slope was established. It is clarified that the structural-lithological reservoirs are mainly developed in the northern part of fault terrace zone, while the strata and lithological reservoirs are mainly developed in the southern high-slope area.