陕北斜坡上古生界构造裂缝及其天然气成藏意义  

Fractures of the Upper Paleozoic in Northern Shaanxi Slope and Its Natural Gas Accumulation Significance

作　　者：万永平[1,2] 王根厚[1] 归榕[1] 李春霞 银晓 周进松 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]陕西延长石油(集团)有限责任公司研究院,西安710075

出　　处：《吉林大学学报（地球科学版）》2013年第1期28-38,共11页Journal of Jilin University：Earth Science Edition

基　　金：国家科技支撑计划项目(2007BAB17B00);中国科学院油气资源研究重点实验室开放课题(2012-03)

摘　　要：鄂尔多斯盆地陕北斜坡上古生界气藏发育多套储层,中上部储层(石盒子组及石千峰组)与烃源岩(山西组下部及本溪组煤系地层)之间发育280～350m致密砂泥岩隔层,由于盆地断裂构造不发育,天然气运移通道及成藏模式成为该区气藏研究的焦点。在岩心观察、微裂缝研究、测井解释、岩心孔隙度-渗透率实验研究的基础上,结合成岩作用及裂缝形成时间分析,对研究区上古生界隔层裂缝分布与中上部气藏之间的匹配关系进行了系统研究。结果表明:研究区上古生界主要发育剪性裂缝,裂缝形成于晚侏罗世早白垩世,裂缝的形成在改善储层渗透性的同时,为天然气的纵向运移提供了必要的运移通道。综合分析认为:研究区上古生界隔层裂缝与中上部气藏在时空上具有良好的耦合关系,形成了基于裂缝运移及砂岩储存的石盒子组与石千峰组"岩性-裂缝型"气藏。Due to the low-permeability and tight sandstone reservoirs, as well as the huge thick insulating layer formed between the source rocks and the shallow reservoirs（Shihezi and Shiqianfeng Formation）of Upper Paleozoic in northern Shaanxi slope, Ordos basin, it is significant to study on the natural gas migration channels and it ~s accumulation model. Based on the core and micro-fracture observation, logging interpretation, porosity-permeability analysis, and the analysis of diagenesis together with fracture-forming time, we have focused on the matching relationship between fractures distribution in the insulating layers and the natural gas pools in the shallow reservoirs. It is believed that the mainly sheering fractures, developed between Late Jurassic and Early Cretaceous, improved permeability and provided migration channels for natural gas synchronously. According to the studies above-mentioned, it is proposed that the shallow gas reservoirs have a good coupling relationship with fractures in the insulating layers on time and space. Based on the fracture migration and sandstone storage, a natural gas accumulation model was presented to show the reservoirs of Shihezi and Shiqianfeng Formations, which is named as lithologic-fractural gas reservoir.

关 键 词：陕北斜坡 上古生界 裂缝 运移通道 天然气 成藏 

分 类 号：P618.13[天文地球—矿床学]