石油学报 ›› 2025, Vol. 46 ›› Issue (4): 661-675,742.DOI: 10.7623/syxb202504001

• 地质勘探 •    

四川盆地川中地区龙女寺茅口组白云岩气田勘探发现及其意义

谢继容1, 罗冰2, 张玺华2, 张本健2, 陈聪2, 冉崎1, 赵容容3, 彭瀚霖2, 李天军2, 陈康2, 赖强2, 何青林2, 李文正4, 袁海锋5, 胡广6   

  1. 1. 中国石油西南油气田公司 四川成都 610051;
    2. 中国石油西南油气田公司勘探开发研究院 四川成都 610041;
    3. 中国石油西南油气田公司勘探事业部 四川成都 610041;
    4. 中国石油杭州地质研究院 浙江杭州 310023;
    5. 油气藏地质及开发工程全国重点实验室(成都理工大学) 四川成都 610059;
    6. 油气藏地质及开发工程全国重点实验室(西南石油大学) 四川成都 610500
  • 收稿日期:2024-11-22 修回日期:2025-01-21 发布日期:2025-05-10
  • 通讯作者: 陈聪,男,1985年11月生,2016年获成都理工大学博士学位,现为中国石油西南油气田公司勘探开发研究院一级工程师,主要从事石油天然气地质勘探研究工作。Email:chenc2016@petrochina.com.cn
  • 作者简介:谢继容,男,1969年3月生,1996年获成都理工大学硕士学位,现为中国石油西南油气田公司地质勘探高级专家、正高级工程师,主要从事石油天然气地质勘探与技术管理工作。Email:xiejr@petrochina.com.cn
  • 基金资助:
    中国石油天然气股份有限公司科技重大专项“海相碳酸盐岩油气规模增储上产与勘探开发技术研究”(2023ZZ16)资助。

Exploration and discovery of the Maokou Formation dolomite gas field in Longnüsi area of central Sichuan Basin and its significance

Xie Jirong1, Luo Bing2, Zhang Xihua2, Zhang Benjian2, Chen Cong2, Ran Qi1, Zhao Rongrong3, Peng Hanlin2, Li Tianjun2, Chen Kang2, Lai Qiang2, He Qinglin2, Li Wenzheng4, Yuan Haifeng5, Hu Guang6   

  1. 1. PetroChina Southwest Oil & Gasfield Company, Sichuan Chengdu 610051, China;
    2. Research Institute of Exploration and Development, PetroChina Southwest Oil & Gasfield Company, Sichuan Chengdu 610041, China;
    3. Exploration Department, PetroChina Southwest Oil & Gasfield Company, Sichuan Chengdu 610041, China;
    4. PetroChina Hangzhou Institute of Geology, Zhejiang Hangzhou 310023, China;
    5. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Sichuan Chengdu 610059, China;
    6. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Sichuan Chengdu 610500, China
  • Received:2024-11-22 Revised:2025-01-21 Published:2025-05-10

摘要: 2023年,四川盆地中部地区龙女寺区块茅口组二段(茅二段)勘探获得重大突破,向自然资源部提交探明储量超过460×108m3,是四川盆地茅口组60年勘探历程中发现的首个大型气藏。截至2024年,中国石油天然气股份有限公司在川中地区茅口组探明天然气地质储量超过1 500×108m3,茅口组成为四川盆地增储上产重要新领域。主要取得以下认识:①创新提出了川中古隆起对茅二段沉积早期的古地貌分异具有显著控制作用,古隆起边缘发育的坡折带是高能滩体发育的有利区,龙女寺—合川—南充地区的滩体厚度大,是勘探的有利突破口。②川中地区龙女寺区块的高能滩相遭受了早期暴露溶蚀及浅埋藏等多期白云岩化作用,可形成茅二段优质白云岩储层,为规模成藏提供储集空间条件。研究区内的茅二段下亚段发育裂缝-孔隙型优质储层,储层厚度为5~30 m,岩心孔隙度为2%~8%,渗透率为0.01~1.00 mD。③多源接力供烃、早期成储成圈是川中地区龙女寺区块茅口组规模成藏的主要机理。寒武系筇竹寺组、志留系龙马溪组和二叠系茅口组一段优质烃源岩先后成熟且持续供烃,这为龙女寺区块的茅口组气藏提供了从中三叠世至晚垩世的4期持续油气充注。高能滩相储层早期成储,且滩体外有致密灰岩封堵,由此形成早期岩性圈闭,有利于规模成藏。④龙女寺—合川—南充一带是茅二段下亚段勘探最有利区,川西地区雅安—都江堰一带、川北地区盐亭区块、蜀南地区泸州区块具有相似的沉积背景和有利成藏条件,是下一步勘探的潜在有利区。

关键词: 四川盆地, 龙女寺区块, 二叠系茅口组, 滩相白云岩储层, 大型岩性气藏

Abstract: In 2023, a major breakthrough was achieved in exploration of the Member 2 of Maokou Formation in Longnüsi area of central Sichuan Basin. The proven reserves submitted to Ministry of Natural Resources of the People’s Republic of China exceeded 460×108m3, marking the first large-scale gas reservoir discovered in the 60-year exploration history of Maokou Formation in Sichuan Basin. As of 2024, PetroChina Company Limited has proven geological reserves of natural gas exceeding 1 500×108m3 in Maokou Formation of central Sichuan Basin, making the Maokou Formation an important new field for increasing reserves and production in the Sichuan Basin. The main understandings obtained are as follows. (1) It is innovatively proposed that the paleo-uplift of central Sichuan Basin has a significant controlling effect on the differentiation of ancient landforms in the early sedimentary period of the Member 2 of Maokou Formation. The slope break zone developed at the edge of the paleo-uplift is a favorable area for the development of high-energy shoals. The shoal thickness is large in Longnüsi-Hechuan-Nanchong area, which is a favorable breakthrough area for exploration. (2) The high-energy shoal facies in Longnüsi area of central Sichuan Basin has undergone multiple dolomitization processes such as early exposure, dissolution and shallow burial, resulting in the formation of high-quality dolomite reservoirs in the Member 2 of Maokou Formation and providing reservoir space conditions for large-scale accumulation. The lower submember of Member 2 of Maokou Formation in the study area develops fracture-pore type high-quality reservoirs, with thickness from 5 m to 30 m, core porosity from 2 % to 8 %, and permeability from 0.01 mD to 1.00 mD. (3) The large-scale hydrocarbon accumulation in Maokou Formation of the Longnüsi area was mainly controlled by multi-source relay hydrocarbon supply, early reservoir formation and trap formation. High-quality source rocks from the Cambrian Qiongzhusi Formation, the Silurian Longmaxi Formation, and the Member 1 of Permian Maokou Formation successively played an important role in sustained hydrocarbon supply after maturation, providing four-stage continuous oil and gas charging from Middle Triassic to Late Cretaceous in Maokou Formation. Early-stage hydrocarbon accumulation occurred in high-energy shoal facies reservoirs, which were laterally sealed by tight limestone, forming early lithologic traps favorable for the formation of large-scale gas reservoirs. (4) The Longnüsi-Hechuan-Nanchong area is the most favorable exploration area for the lower submember of Member 2 of Maokou Formation. The Ya’an-Dujiangyan area in western Sichuan Basin, the Yanting area in northern Sichuan Basin, and the Luzhou area in southern Sichuan Basin have similar sedimentary backgrounds and favorable accumulation conditions, and are potential favorable areas for the next exploration.

Key words: Sichuan Basin, Longnüsi area, Permian Maokou Formation, shoal facies dolomite reservoir, large-scale lithologic gas reservoir

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