Acta Petrolei Sinica ›› 2025, Vol. 46 ›› Issue (9): 1688-1706.DOI: 10.7623/syxb202509004

• PETROLEUM EXPLORATION • Previous Articles    

Forward modeling of natural gas migration and accumulation history of Sinian Dengying Formation in Deyang-Changning rift trough and its periphery,southern Sichuan Basin

Li Bin1,2, Jiang Hua3, Qu Haizhou1, Long Hui4, Geng Chao4, Du Yu1, Wang Rui1   

  1. 1. School of Geoscience and Technology, Southwest Petroleum University, Sichuan Chengdu 610500, China;
    2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Sichuan Chengdu 610500, China;
    3. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
    4. Research Institute of Exploration and Development, PetroChina Southwest Oil & Gasfield Company, Sichuan Chengdu 610041, China
  • Received:2024-10-11 Revised:2025-03-31 Published:2025-10-11

蜀南地区德阳—长宁裂陷槽及其周缘震旦系灯影组天然气运聚成藏历史正演模拟

李斌1,2, 姜华3, 屈海洲1, 隆辉4, 耿超4, 杜宇1, 王瑞1   

  1. 1. 西南石油大学地球科学与技术学院 四川成都 610500;
    2. 西南石油大学油气藏地质及开发工程国家重点实验室 四川成都 610500;
    3. 中国石油勘探开发研究院 北京 100083;
    4. 中国石油西南油气田公司勘探开发研究院 四川成都 610041
  • 通讯作者: 李斌,男,1977年2月生,2006年获中国科学院大学博士学位,现为西南石油大学副教授,主要从事油气成藏机理研究工作。
  • 作者简介:李斌,男,1977年2月生,2006年获中国科学院大学博士学位,现为西南石油大学副教授,主要从事油气成藏机理研究工作。Email:lbin@swpu.edu.cn
  • 基金资助:
    中国石油天然气股份有限公司科学研究与技术开发项目"海相碳酸盐岩成藏理论与勘探技术研究"(2021DJ05)和四川省区域创新合作项目"复杂油藏高效开发相关技术研究及推广应用"(2021YFQ0048)资助。

Abstract: This study focus on the unclear hydrocarbon enrichment pattern of Sinian Dengying Formation in Deyang-Changning rift trough and its periphery, southern Sichuan Basin. To address this problem, the dynamic evolution history of petroleum systems involving various reservoir-caprock assemblages in Dengying Formation has been reconstructed by forward modeling of hydrocarbon accumulation. Based on the paleogeomorphic and lithofacies paleogeographic characteristics of Dengying Formation, the study area can be divided into five tectonic-sedimentary facies belts, i.e., the inner belt of east platform margin, the slope belt of east platform margin, the west platform margin belt, the inner platform belt, and the rift belt. The rift trough-platform tectonic framework plays a significant role in controlling the thermal evolution of the Lower Cambrian source rocks in southern Sichuan Basin. The hydrocarbon generation time and generation potential exhibit a sequential descending from the rift belt to the inner platform shoal belt to the platform margin belt. The configuration of lateral hydrocarbon generation and proximal accumulation is more conducive to oil and gas charging, and the trap filling degree of reservoir is positively correlated with the trap height. Formation pressure is a critical factor influencing hydrocarbon charging efficiency in Dengying Formation. Under normal pressure conditions, the hydrocarbon filling degrees shows a decrease in the order of the east platform margin belt, the west platform margin belt, the inner platform belt, and the rift belt. The impact of paleogeomorphology on trap filling degrees of Dengying Formation also shows a sequential decrease from the platform margin belt to the inner platform belt and then to the rift belt. Fluid potential simulations reveal that the Hercynian period was crucial for the formation of primary hydrocarbon reservoirs in the rift belt, while the Himalayan period was the final adjustment stage for the present reservoirs, and the Caledonian paleo-uplift controlled the differential hydrocarbon accumulation patterns across various structural belts in southern Sichuan Basin. It is revealed by forward modeling of the petroleum system that the hydrocarbon enrichment in Dengying Formation is primarily dominated by the synergistic control of source-reservoir-caprock assemblages, charging dynamics, and trap type. The most favorable zones for hydrocarbon enrichment occur in the convergence areas featuring lateral hydrocarbon generation and proximal accumulation, overpressure environments, and structural traps. The exploration targets in the study area should be the relatively over-pressured areas, particularly the second to third terraces of the east platform margin and the mound-shoal complex areas of the inner platform belt. The target area in rift belt require proximity to migration pathways in the steep slope zone. The research aims to provide new perspectives for the dynamic quantitative evaluation of deep hydrocarbons in Sichuan Basin, and also offer a reference for studying the hydrocarbon enrichment patterns in deep and ultra-deep negative tectonic units of superimposed basins in China.

Key words: forward modeling of hydrocarbon accumulation, petroleum system, Dengying Formation, rift trough, southern Sichuan Basin

摘要: 针对蜀南地区德阳—长宁裂陷槽及其周缘震旦系灯影组油气富集规律认识不清的问题,采用成藏正演模拟方法,恢复了灯影组不同储-盖组合含油气系统的动态演化历史。根据灯影组的古地貌与岩相古地理特征,研究区可划分为东台缘台内带、东台缘斜坡带、西台缘带、台内带和裂陷槽带5个构造-沉积相带。裂陷槽-台地的构造格局显著控制了蜀南地区下寒武统烃源岩的热演化过程,生烃时间和生烃潜量呈现裂陷槽带>台内滩>台缘带的有序分布特征。侧生邻储型配置更有利于油气高效充注,且圈闭的油气充满度与闭合高度呈正相关关系。地层压力是影响研究区油气充注效率的关键因素,常压环境下油气充满度表现为东台缘带>西台缘带>台内带>裂陷槽带,古地貌对灯影组圈闭的油气充满度的影响强度表现为台缘带>台内带>裂陷槽带。流体势模拟揭示,海西期为裂陷槽带原生油气藏形成的关键期,喜马拉雅期为蜀南地区的构造定型期,加里东期的古隆起奠定了蜀南地区不同构造带油气的差异成藏格局。蜀南地区灯影组的油气富集主要受生-储-盖组合类型、充注动力和圈闭类型协同控制,其中,侧生邻储型配置、超压环境与构造圈闭的叠合区为最有利富集区带。研究区的勘探目标应优先考虑相对高压区,重点勘探东台缘带二台阶—三台阶和台内带丘滩体发育区,裂陷槽带的目标优选应靠近陡坡带优势运移通道区。研究认识以期为四川盆地深层油气的动态定量评价提供新思路,也为中国叠合盆地深层—超深层负向构造单元油气富集规律研究提供参考。

关键词: 成藏正演模拟, 含油气系统, 灯影组, 裂陷槽, 蜀南地区

CLC Number: