【作者】 刘四兵；

【导师】 沈忠民；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2007， 硕士

【摘要】 作者简介：刘四兵，男，1981年9月生，2004年从师于沈忠民教授，于2007年6月毕业于成都理工大学矿产普查与勘探专业。川西坳陷致密碎屑岩含气领域是四川盆地重要的天然气能源生产基地，该区天然气资源量达18000～25000×10~8m~3，资源十分丰富。但目前所获天然气探明加控制储量2300×10~8m~3仅占总资源的10.7％，且主要集中在侏罗系浅、中层领域。上三叠统须家河组属川西地区深层勘探领域，埋深一般大于3000m。随着浅、中层油气勘探全面突破和整体投入开发，川西坳陷油气勘探实现可持续发展和稳步增长的战略形势迫切要求寻找深层上三叠统油气勘探的大规模突破，使之尽快成为浅、中层侏罗系气藏的后备接替领域。本次研究在前人(曹烈等，2005)工作的基础上，通过现今构造的分布与特征，采用多种古构造研究技术重塑了川西中段的构造演化史。通过盆地模拟技术研究了关键时期古流体势，研究了成藏时期的圈闭场所油气充注的动力条件，深化川西前陆盆地油气运移富集规律认识。研究内容主要包括以下几个方面：①在前人工作及现今构造研究的基础上，运用地质、盆地模拟等方法研究川西坳陷中段须家河组各关键时期的古构造分布特征。研究表明：须家河组沉积末～遂宁期末，川西中段须二主要为箕状构造，而孝、新、合地区须家河组构造形态为区域性斜坡；侏罗纪末，孝、新、合地区须家河组构造形态为膝状构造的南斜坡；白垩纪末须家河组形成隆起。②须家河组存在两期古水动力场：须家河组沉积末—侏罗纪末，须二段水流由西向东运移，须四段水流由南向北运移；白垩纪末—喜山期末，须二段、须四段的地下水向孝、新、合地区运移。③对川西坳陷中段须二段、须四段的油、气势研究表明：须家河组沉积末～侏罗纪末，须二段流体势方向由西向东、向南、向北，孝泉—新场—合兴场地区位于运移的斜坡上；须四段流体势方向主要是由南向北运移。白垩纪末～喜山末，须二段、须四段的流体势指向孝、新、合地区运移聚集。④对川西坳陷中段须家河组，通过系统的盆地模拟，分析了成藏的生排烃期、聚集期构造和孔隙演化史等地质要素的匹配性，并对须家河组成藏过程中的优势运移通道发育特征进行研究，并进一步优选出了5个有利勘探目标。更多还原

【Abstract】 The tight clastic rock gas pools in the West Sichuan sag is an important production baseof natural gas of Sichuan Basin, in which the potential volume of gas is about 18000～25000×10~8m~3.However, the identified and estimated reserves, which mainly concentrate inthe Jurassic shallow and mesopelagic layers, are 2300×10~8m~3, only to occupy the totalresources 10.7%.The Xu jiahe Formation in upper Triassic, whose average buried depth is 3000m,belongs to deep exploration in the western depression of Sichuan Basin. With the comprehensivebreakthrough and entire production of exploration activity in shallow and mesopelagic layers,the strategic condition of sustainable development and increase in the western depression ofSichuan basin urgently require to finding large scale breakthrough of exploration activity in deep upperTriassic, in order to make it the backup of gas reservoir in the Jurassic shallow and mesopelagiclayers.Based on the work of predecessors and pattern of present structure, we adopt multiplepalaeotectonic research methods to remold the structural evolution of west-Sichuan sag.Through basin modeling, we studied the paleo-fluid potential in the critical period, thedynamic condition of hydrocarbon emplacement in trap structure of reservoiring period andintensified knowledge of accumulation regular of oil and gas in the western Sichuan forelandbasin. The studies mainly include:①Based on the work of predecessors, we studied the palaeotectonic pattern in thecritical period of the Xu jiahe Formation of middle west-Sichuan sag, using the methods of geologicand basin modelling and so on. The studies show that, in the period of Xu jiahepost-sedimentation～post-Suining, the structural feature of the middle west-Sichuan sag at section Xu 2is mainly half structure, but the Xu jiahe formation in Xiaoquan, Xinchang and He xinchang area ismainly areal slope. In the end of Jurassic, the structural feature of the Xu jiahe formation in Xiaoquan,Xinchang and He xinchang area is mainly geniculate southern slope. And in the end ofCretaceous Period, Xujiahe formation takes shape of uplift.②There are two-step palaeohydrodynamic field in the Xu jiahe formation: in the periodof the Xu jiahe post-sedimentation and post-Jurassic, the streams at section Xu 2 migrate fromwest to east and the streams at section Xu 4 migrate from south to north. In the end ofCretaceous and Xi shah Period, the groundwater at section Xu 2 and 4 migrates to Xiaoquan,Xinchang and He xinchang area. ③The studies of oil and gas potential at section Xu 2 and 4 of middle west-Sichuan sagshow that, in the period of the Xu jiahe post-sedimentation and in post-Jurassic, the fluidpotential at section Xu 2 migrates from west to east, south and north, and Xiaoquan, Xinchangand He xinchang area are situated at migratory slope, and the fluid potential at section Xu 4mainly migrates from south to north. In the end of Cretaceous and Xi shan Period, the fluidpotential at section Xu 2 and 4 migrates to Xiaoquan, Xinchang and He xinchang area.④We analyzed the accumulated hydrocarbon generation and expulsion stage, match ofgeologic feature such as structure of accumulative phase and porous evolution and so on, alsowe studied the developmental feature of dominant migration pathway in the process ofaccumulation in the Xu jiahe formation.更多还原