周口拗陷石炭—二叠系油气资源及其成藏条件

Hydrocarbon Resources and Forming Conditions of Hydrocarbon Reservoir of Permo-Carboniferous in Zhoukou Depression

通过对周口拗陷石炭—二叠系分布、烃源岩特征、生烃史、生储盖组合类型、储集特征、油气输导体系及充注史、圈闭类型及其形成演化以及典型油气藏剖析等综合研究,评价了该区石炭—二叠系油气资源及其成藏条件。结果表明:煤是石炭—二叠系最主要的烃源岩,分布广,厚度大,类型好,生烃潜力高;印支期和喜山期是石炭—二叠系最主要的生烃期;石炭—二叠系油气存在自生自储、下生上储和古潜山3种生储盖组合类型,其中,下生上储型是最重要的生储盖组合类型;石炭—二叠系油气发育有砂岩输导层、不整合面输导层及断裂系统3种输导体系;石炭—二叠系油气主要有印支和喜山两期油气运聚及充注事件;区内发育多种复合构造圈闭、下古生界风化壳岩溶地貌圈闭及上古生界地层—岩性圈闭;喜山期晚期是区内石炭—二叠系最主要油气生成和运聚期,并且圈闭定型期与油气运聚期配置良好;南12井油藏是区内石炭—二叠系油气资源的重大发现。总之,该区石炭—二叠系油气资源潜力较大,成藏条件有利,有望获得油气勘探的突破。

According to synthetically studies on the Permo-Carboniferous distribution in the Zhoukou depression, oil source rock features, hydrocarbon-generating history, assembling types of the oil-generating strata, reservoir strata and overlying strata, oil transforming systems and filling history, trap types as well as their forming and evolution, and the typical hydrocarbon reservoir, this paper aims to probe into the hydrocarbon resources and forming conditions of reservoir of the Permo-Carboniferous in the Zhoukou depression. The research indicates that the coal is the main generating rock of the Permo-Carhoniferous because of its extensive distribution, large thickness, good kerogen types and high hydrocarbon potential. The Indosinian epoch and Yanshan epoch are the most important periods for hydrocarbon formation. The assembling types of the oil-generating strata, reservoir strata and overlying strata include self-generation and self-accumulation ones, super-generation and loweraccumulation ones and buried hill ones, among which the most important is the super-generation and loweraccumulation ones. The transforming systems for the Permo-Carboniferous hydrocarbon include sandstone ones, hard ground ones and rift system ones. The trap types in this area include compound structural ones, residual paleo-karst landform ones of the lower Palaeozoic Erathem, stratigraphy-lithology ones of the upper Palaeozoic Erathem. The late Himalayan epoch is the foremost for the Permo-Carboniferous hydrocarbon generation and accumulation, and the formalization time of trap match well with that of hydrocarbon accumulation. The Nanl2- well reservoir is a great finding of the Permo-Carboniferous hydrocarbon resources in this area. In a word, the Permo-Carboniferous in this region have high resources potential and favorable forming conditions of hydrocarbon reservoir, and this region is a favorable to scquire breakthrough in the exploration activity.