石油与天然气地质 ›› 2024, Vol. 45 ›› Issue (6): 1705-1719.doi: 10.11743/ogg20240616

• 油气地质 • 上一篇    下一篇

川中地区中侏罗统沙溪庙组断层输导有效性定量评价

刘景东1,2(), 任成刚1, 王小娟3, 潘珂3, 王少华1, 庞小婷3, 关旭3   

  1. 1.深层油气全国重点实验室 中国石油大学(华东),山东 青岛 266580
    2.中国石油大学(华东) 地球科学与技术学院,山东 青岛 266580
    3.中国石油 西南油气田公司 勘探开发研究院,四川 成都 610051
  • 收稿日期:2024-04-13 修回日期:2024-08-09 出版日期:2024-12-30 发布日期:2024-12-31
  • 第一作者简介:刘景东(1984—),男,博士、教授,油气地质与勘探。E-mail:liujingdong@upc.edu.cn
  • 基金项目:
    中国石油西南油气田公司重大科技专项(2022ZD01-01)

Quantitative assessment of hydrocarbon transport effectiveness along faults in the Middle Jurassic Shaximiao Formation, central Sichuan Basin

Jingdong LIU1,2(), Chenggang REN1, Xiaojuan WANG3, Ke PAN3, Shaohua WANG1, Xiaoting PANG3, Xu GUAN3   

  1. 1.State Key Laboratory of Deep Oil and Gas,China University of Petroleum (East China),Qingdao,Shandong 266580,China
    2.School of Geosciences,China University of Petroleum (East China),Qingdao,Shandong 266580,China
    3.Exploration and Development Research Institute,Southwest Oil & Gasfield Company,PetroChina,Chengdu,Sichuan 610051,China
  • Received:2024-04-13 Revised:2024-08-09 Online:2024-12-30 Published:2024-12-31

摘要:

断层输导有效性是中浅层油气成藏和富集的关键因素。开展断层输导有效性评价对四川盆地中部(川中)中浅层油气勘探部署具有重要意义。以川中地区中侏罗统沙溪庙组为例,在断层分布与成因分析的基础上,采用断层活动速率、挤压应力方向和断面正压力等方法,评价了气源断层输导性,研究了断-砂配置及其演化,揭示了断-砂配置对天然气运移及富集差异的控制作用。研究表明:川中地区分别切割上三叠统须家河组和下侏罗统烃源岩的逆断层和正断层,为沙溪庙组的气源断层,其中逆断层受控于不同构造运动期的构造挤压,正断层成因是沙溪庙组沉积早-中期“弱伸展背景下的隆-坳差异沉降”;川中地区龙泉山、角①和简阳①逆断层及正断层在晚燕山期和晚喜马拉雅期具有较好的输导性,受断层规模和下伏气源供给等因素影响,龙泉山断层和角①断层为最重要的输导断层;川中地区气源断层多数表现为早-晚继承型,有利于天然气在不同充注期向有利砂体持续充注,而角①断层为早-晚反转型,早期和晚期的天然气充注方向不同,在断层两侧均可发生天然气充注;气源断层规模、断-砂配置关系及烃源岩生烃强度是天然气富集差异的主控因素。

关键词: 断-砂配置演化, 定量评价, 断层输导性, 天然气运移, 沙溪庙组, 中侏罗统, 中浅层, 四川盆地

Abstract:

The hydrocarbon transport effectiveness along faults is a key factor influencing hydrocarbon accumulation and enrichment in moderately shallow reservoirs. Assessing this factor holds great significance for the emplacement of hydrocarbon exploratory wells in medium-shallow reservoirs in the central Sichuan Basin. This study focuses on the Shaximiao Formation in the central Sichuan Basin. Following the analysis of fault distributions and origins, we assess the gas transport capacity of source rock-rooted faults, investigate the fault-sand configuration and its evolution, and reveal the controlling effects of fault-sand configuration on the migration and differential enrichment of gas, based on fault activity rates, compressive stress directions, and normal stress on fault plane. The results indicate that the reverse and normal faults cutting through the Upper Triassic Xujiahe Formation and the Lower Jurassic source rocks in the central Sichuan Basin serve as the source rock-rooted faults of the Shaximiao Formation. The reverse faults, among others, are governed by the tectonic compression in different tectonic movement periods, whereas the normal faults are formed due to the differential subsidence with uplifting and sagging in a weak extensional setting during the early to middle sedimentary stages of the Shaximiao Formation. The reverse faults, Longquanshan, Jiao-1, and Jianyang-1, as well as normal faults in the central Sichuan Basin exhibit high transport capacity during the Late Yanshanian and the Late Himalayan. Considering factors such as fault size and the hydrocarbon generation intensity of underlying gas sources, it can be inferred that the Longquanshan and Jiao-1 faults play the most significant role in hydrocarbon transport. The source rock-rooted faults in the central Sichuan Basin are mostly of the inherited type, conducive to the continuous gas charge into favorable sand bodies in different charging periods. In contrast, the Jiao-1 fault is of the inverted type, exhibiting different gas charge directions in the early and late stages and allowing for natural gas charge on both sides. Major factors governing the differences in natural gas enrichment include the size of source rock-rooted faults, fault-sand configuration, and the hydrocarbon generation intensity of source rocks.

Key words: fault-sand configuration evolution, quantitative assessment, transport capacity of a fault, natural gas migration, Shaximiao Formation, Middle Jurassic, medium-shallow reservoir, Sichuan Basin

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