姬塬地区延长组长2油藏油气成藏条件研究

姬塬地区是鄂尔多斯盆地重点油气勘探区域之一。系统研究姬塬地区长2油藏的烃源岩、储集层、油气运移以及油气圈闭条件等,并综合分析了长2油藏的油气成藏条件。研究结果表明:姬塬地区紧邻盆地延长组生烃中心,油气供应充分,长2油藏的油气主要来自长7烃源岩;主要储层是水下分流河道砂体,岩石成分以长石砂岩、岩屑长石砂岩为主,极少量长石岩屑砂岩,为近中孔隙度、低渗透率储层;成岩作用类型主要有压实作用、胶结作用、溶蚀作用等。长7地层产生的异常高压是长7烃源岩产生的油气自下而上运移到长2地层的主要驱动力。研究区长2油藏的圈闭主要是构造-岩性圈闭,局部地区发育有构造圈闭和岩性圈闭。长2地层发育厚度较大的分流间湾泥岩均充当了长2油藏必备的遮挡和封盖层。

Hydrocarbon accumulation conditions of Chang 2 oil reservoir set in Jiyuan area, Ordos Basin

Jiyuan area is one of the key oil and gas exploration area within the basin. Based on the research of source rocks, reservoir rocks, hydrocarbon migration and traps, this paper synthetically analyzed the hydrocarbon accumulation conditions of Chang 2 oil reservoir set in Jiyuan area. The result shows that hydrocarbon of Chang 2 oil reservoir mainly comes from Chang 7 source rocks. The reservoir in the study area is mostly underwater distributary channel sand bodies, and sandstone is mainly composed of arknse, lithic arkose, with little feldspathie lithic sandstone, so it belongs to moderate porosity and low permeability reservoir. Compaction, cementation and dissolution are the main diagenesis lypes. The abnormal high pressure from Chang 7 oil reservoir set drives the nil generated from Chang 7 source rocks up to Chang 2 oil reservoir set. The oil in Chang 2 oil reservoir set is mainly Irapped by structural-lithologic trap, with local area by structural trap and lilhologic trap. The thick interdistribulary mudstone developed in Chang 2 oil reserw,ir set plays the necessary role as the shieht and cap rock of Chang 2 oil reservoir set.