酒泉盆地青西凹陷油气地质特征及下步勘探方向  

Oil-gas geological features and exploration direction in the Qingxi Sag,Jiuquan Basin

作　　者：魏浩元 朱宗良 肖文华 魏军 韦德强 苑伯超 向鑫 WEI Haoyuan;ZHU Zongliang;XIAO Wenhua;WEI Jun;WEI Deqiang;YUAN Bochao;XIANG Xin(Research Institute of Exploration and Development,Yumen Oilfield Company,PetroChina,Jiuquan 735019,China)

机构地区：[1]中国石油玉门油田分公司勘探开发研究院,甘肃酒泉735019

出　　处：《地学前缘》2023年第1期69-80,共12页Earth Science Frontiers

基　　金：中国石油勘探与生产分公司科技项目“新区新领域及中小盆地综合地质研究——玉门探区重点勘探领域综合研究与预探目标评价(kt2021-06-09)”。

摘　　要：酒泉盆地油气勘探始于20世纪20年代,先后发现了老君庙、鸭儿峡、单北、白杨河等油田。盆地在中、新生代经历了早白垩世断陷盆地演化阶段和新生代前陆盆地演化阶段,为断拗叠置型盆地。断陷期的酒泉盆地下白垩统赤金堡组和下沟组为一套纹层状泥质白云岩和白云质泥岩,藻纹层比较发育,是优质的烃源岩。拗陷期盆地的快速沉降导致烃源岩快速成熟、高效生烃,为油气运移提供了动力,同时挤压逆冲对构造圈闭、油气运移通道的形成和储层物性的改善起着关键的作用,形成的窟窿山等多个正向构造带是油气富集的有利区带。青西凹陷存在低成熟、成熟、高成熟3类原油,低成熟原油仅分布于青西凹陷的下沟组上段至中沟组,成熟原油发生了大规模的运移,形成了柳沟庄、鸭儿峡—老君庙—石油沟油田,而深层高成熟原油没有大规模向中浅层运移,青西凹陷具有寻找高成熟原油的资源潜力。希望该研究成果可为青西凹陷下白垩统油气勘探提供经验与思路。Petroleum exploration in the Jiuquan Basin begins in the 1920s with the successive discoveries of the Laojunmiao,Yaerxia and Danbei oilfields.The basin is a fault/depression superimposed basin formed through two-stage evolution—Early Cretaceous fault depression and Mesozoic-Cenozoic foreland,where a set of laminar argillaceous dolomite and dolomitic mudstone deposited in the Lower Cretaceous Chijinbao and Xiagou formations during the fault depression period.The relatively developed algal dolomite is high-quality source rock,and rapid basin subsidence during the depression period lead to the quick maturation of source rock and efficient hydrocarbon generation,which provides strong driving force for oil and gas migration.At the same time,compression and thrust play a key role in the generation of structural traps and migration channels as well as improvement of reservoir physical properties.Many positive structural belts,such as the Kulongshan mountain range,are favorable areas for oil and gas enrichment.There are three types of crude oil in the Qingxi Sag according to thermal maturity.The low-maturity crude oil is only found in the upper Xiagou-Zhonggou formations;mature crude oil,capable of large-scale migration,are distributed in the Liugouzhuang,Yaerxia,Laojunmiao and Shiyougou oilfields;and deep high-maturity crude oil,largely confined below the medium and shallow layers,presents promising resource potential.The above results provides a valuable reference for the petroleum exploration in the Lower-Cretaceous Qingxi Sag.

关 键 词：酒泉盆地 断拗叠置 藻纹层 烃源岩 挤压 逆冲 运移通道 正向构造 资源潜力 

分 类 号：TE132[石油与天然气工程—油气勘探]