冀中坳陷洼槽地质特征及其与油气分布关系

Geological characteristics of sub-sags and their relation with hydrocarbon distribution in Jizhong Depression

基于三维地震、钻录井、地化等资料,对冀中坳陷洼槽进行了分类,并对不同类型洼槽沉积充填和地质结构特征进行了研究,评价了不同洼槽生烃潜力,探讨了洼槽地质特征与油气分布关系。结果表明:冀中坳陷共发育29个洼槽,根据古近系沉积充填特征,可划分为早期型、继承Ⅰ型、继承Ⅱ型和晚期型等4类,不同类型洼槽沉积充填差异悬殊,生烃潜力存在明显差异,其中继承Ⅰ型和继承Ⅱ型洼槽控制了富生烃洼槽的发育,进而控制了主要油气资源的空间分布;研究区洼槽地质结构类型多样,可划分为单断断超式、单断反转式、单断断阶式和双断地堑式等4种类型,洼槽结构控制油气运移主要方向,形成5种类型油气富集带,其油气藏类型及分布表现出明显差异性。综合洼槽沉积、结构及生烃潜力研究,预测出研究区7个富生烃洼槽及其12个有利油气富集带,为洼槽区岩性油气藏勘探提供理论依据。

Based on 3D seismic, drilling, logging, and geochemical data, we conduct a research on geological characteristics of sub-sags and their relation with hydrocarbon distribution in Jizhong Depression. 29 sub-sags in Jizhong Depression are classified, their sedimentary filling and geological structure characteristics are studied, and their hydrocarbon generation potential is quantitatively evaluated. These 29 sub-sags developed in Jizhong can be divided into of 4 types: early-formed type, inherited-formed type I, inherited type II, and late-formed type. The sedimentary filling and hydrocarbon potential characteristics in these sub-sags are different, among which inherited I and inherite II sub-sags control the hydrocarbon rich development, and then control hydrocarbon spatial distribution. Jizhong Depression developed various sag structures which can be divided into 4 types named single-fault with on-lap, single-fault with bench, single-fault with reverse, and double-fault with graben. The sag structures control the main direction of hydrocarbon migration, and 5 types of oil and gas enrichment zone are formed with different reservoir types and distribution. Based on characteristics of structures and hydrocarbon potential, we predict hydrocarbon rich sags and 12 hydrocarbon enrichment zones to provide a theoretical basis for the future hydrocarbon exploration. © 2016, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.