石油学报 ›› 2025, Vol. 46 ›› Issue (6): 1056-1073,1125.DOI: 10.7623/syxb202506003

• 地质勘探 • 上一篇    

川南地区筠连复杂山地浅层改造区薄互煤层气勘探开发关键技术与创新实践

单长安1,2, 梁兴3, 张卓3, 罗瑀峰3, 彭丽莎3, 袁晓俊3, 费越1,2, 范小东3, 于宝石3, 张永强3, 党伟1,2   

  1. 1. 西安石油大学地球科学与工程学院 陕西西安 710065;
    2. 陕西省油气成藏地质学重点实验室 陕西西安 710065;
    3. 中国石油浙江油田公司 浙江杭州 311100
  • 收稿日期:2025-01-09 修回日期:2025-05-15 发布日期:2025-06-28
  • 通讯作者: 梁兴,男,1965年3月生,2006年获西南石油大学矿产普查与勘探专业博士学位,现为中国石油浙江油田公司正高级工程师,主要从事页岩油气、煤层气、灰质源岩气、常规气等领域地质工程一体化综合评价与勘探开发部署规划、工程技术研究。Email:liangx85@126.com
  • 作者简介:单长安,男,1985年11月生,2016年获西南石油大学矿产普查与勘探专业博士学位,现为西安石油大学副教授,主要从事页岩油气、煤层气地质综合评价等研究。Email:shanca@xsyu.edu.cn
  • 基金资助:
    国家重点研发计划"变革性技术关键科学问题"重点专项"川南国家级页岩气示范区地震活动性风险评估与对策研究"(2020YEA0710604)和"分布式光纤地震成像与反演的关键技术及应用研究"(2021YEA0716800)资助。

Key technologies and innovative practices for exploration and development of thin interbedded coalbed methane in the shallow transformation zone of Junlian complex mountainous region,southern Sichuan Basin

Shan Chang'an1,2, Liang Xing3, Zhang Zhuo3, Luo Yufeng3, Peng Lisha3, Yuan Xiaojun3, Fei Yue1,2, Fan Xiaodong3, Yu Baoshi3, Zhang Yongqiang3, Dang Wei1,2   

  1. 1. School of Earth Sciences and Engineering, Xi'an Shiyou University, Shaanxi Xi'an, 710065, China;
    2. Shaanxi Key Laboratory of Petroleum Accumulation Geology, Shaanxi Xi'an 710065, China;
    3. PetroChina Zhejiang Oilfield Company, Zhejiang Hangzhou, 311100, China
  • Received:2025-01-09 Revised:2025-05-15 Published:2025-06-28

摘要: 川南地区筠连煤层气田作为中国南方浅层改造区内已实现规模商业开采的山地煤层气田,其煤层气产量已连续8年达到1×108m3/a以上的稳产。筠连煤层气具有"地处复杂山地,发育于浪控潮坪薄煤层,早期深埋藏高煤阶生烃,晚期浅层改造成藏调整并赋存,煤岩为低渗透,赋存常压型吸附气"的山地煤层气特征。与国内外其他煤层气田相比,筠连煤层气田的高效勘探和效益开发面临着"两无"(无高原山地薄互煤层高阶煤层气勘探开发经验、无成熟的喀斯特岩溶地貌钻压采技术借鉴)和"四难"(乌蒙山地区甜点评选部署难、在喀斯特地貌表层岩溶地质条件下钻压技术实施难、低产水降压智能精细排采难、低产低压低成本山地集输难)的严重挑战。基于筠连煤层气田面临的薄互煤层遭受浅层改造的特点及技术难题,通过系统开展煤层气成藏规律及关键技术研究,明确了川南地区上二叠统乐平组煤层气储层具有"浅层化、过成熟高煤阶、层薄、低渗、低压、低含水"等特征,揭示了山地浅层薄互煤层气藏"潮坪沼泽控煤层、早期深埋-热演化控生烃、晚期浅层化调整控气藏、现今滞留水-承压水区控甜点富集"的赋存富集机理,建立了在盆山耦合浅层改造作用下残留型构造坳陷内"宽缓向斜富气"的甜点模式。攻克了"在碳酸盐岩裸露区喀斯特地貌表层岩溶地质条件下浅层高煤阶薄煤层"山地煤层气勘探开发的技术难题,建立了复杂山地浅层煤层气以"低成本、实用、高效"为特色的一体化甜点评价与部署设计、工厂化优快钻井压裂、智能化精细控压排采以及产销一体化地面集输等浅层低压煤层气连续有效开采技术系列。筠连煤层气田的成功开发标志着中国南方煤层气产业迈出了关键步伐,其勘探地质理论与开发关键技术推动了"筠连模式"的形成和应用,为中国南方乃至其他地区同类型浅层薄互层高煤阶煤层气资源的高效利用和产业链发展提供了重要示范。

关键词: 复杂山地, 浅层化改造, 富集成藏特征, 有效开发关键技术, 筠连煤层气田, 四川盆地

Abstract: The Junlian coalbed methane field in southern Sichuan Basin, as a mountainous coalbed methane field that has achieved large-scale commercial exploitation within the shallow transformation area in southern China, has maintained a stable coalbed methane output of over 1×108m3/a for eight consecutive years. The Junlian coalbed methane has the characteristics of mountainous coalbed methane, which are "located in a complex mountainous area, developed in thin coal seams under the control of waves and tidal flats, deeply buried in the early stage with high-rank coal for hydrocarbon generation, underwent shallow transformation for reservoir adjustment and occurrence in the late stage, had low permeability of coal rock, and contained adsorption gas at normal pressure". Compared with other coalbed methane fields at home and abroad, the efficient exploration and beneficial development of the Junlian coalbed methane fields are confronted with "two deficiencies" (no experience in the exploration and development of high-rank coalbed methane in thin interbedded coal seams on plateau and mountainous areas, and no mature drilling and pressure production technology for karst landforms to draw upon)and "four difficulties" (difficulty in the deployment of sweet spot selection in Wumeng Mountain area, difficulty in implementing drilling and pressure production technology under the karst geological conditions on the surface of karst landforms, difficulty in intelligent and precise drainage and production for low-yield water pressure reduction, and difficulty in gathering and transporting mountainous coalbed methane with low production, low pressure and low cost). Based on the characteristics and technical difficulties of shallow transformation of thin interbedded coal seams faced by the Junlian coalbed methane field, through systematic research on the accumulation laws and key technologies of coalbed methane, it has been clarified that the coalbed methane reservoir of the Upper Permian Leping Formation in southern Sichuan Basin has the characteristics of "shallow transformation, over-maturity with high-rank coal, thin layer, low permeability, low pressure and low water content". The occurrence and enrichment mechanism of shallow and thin interbedded coalbed methane reservoirs in mountainous areas, namely "tidal flat and marsh controlling coal seams, early deep burial-thermal evolution controlling hydrocarbon generation, late and shallow adjustment controlling gas reservoirs, and current retention-confined water area controlling sweet spot enrichment", has been revealed. A sweet spot model of "wide and gentle syncline rich gas" in residual structural depression under the basin-mountain coupling effect of shallow transformation has been established. The technical difficulties in the exploration and development of mountainous coalbed methane under the karst geological conditions of the exposed carbonates have been overcome. A series of continuous and effective exploitation technologies for shallow low-pressure coalbed methane in complex mountainous areas have been established, featuring "low cost, practicality and high efficiency", including integrated sweet spot evaluation and deployment design, factory rapid drilling and fracturing, intelligent precise pressure control drainage and production, as well as integrated production and sales of surface gathering and transportation. The successful development of the Junlian coalbed methane field marks a crucial step forward for the coalbed methane industry in southern China. Its exploration geological theory and key development technologies have promoted the formation and application of the "Junlian Model", providing an important demonstration for the efficient utilization and industrial chain development of the same type of shallow, thin-interlayer and high-rank coalbed methane resources in southern China and other regions.

Key words: complex mountain, shallow transformation, enrichment and accumulation characteristics, key technologies for effective development, Junlian coalbed methane field, Sichuan Basin

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