Acta Petrolei Sinica ›› 2023, Vol. 44 ›› Issue (11): 1827-1839.DOI: 10.7623/syxb202311006

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Breakthrough, future challenges and countermeasures of deep coalbed methane in the eastern margin of Ordos Basin: a case study of Linxing-Shenfu block

Liu Jianzhong, Zhu Guanghui, Liu Yancheng, Chao Weiwei, Du Jia, Yang Qi, Mi Honggang, Zhang Shouren   

  1. China United Coalbed Methane Corporation Ltd., Beijing 100015, China
  • Received:2023-06-26 Revised:2023-10-02 Online:2023-11-25 Published:2023-12-08

鄂尔多斯盆地东缘深部煤层气勘探突破及未来面临的挑战与对策——以临兴—神府区块为例

刘建忠, 朱光辉, 刘彦成, 晁巍巍, 杜佳, 杨琦, 米洪刚, 张守仁   

  1. 中联煤层气有限责任公司 北京 100015
  • 通讯作者: 刘彦成,男,1985年5月,2011年获西南石油大学油气田开发工程专业硕士学位,现为中联煤层气有限责任公司高级工程师,主要从事油气田开发及生产科研工作。Email:liuych@cnooc.com.cn
  • 作者简介:刘建忠,男,1974年8月生,2009年获西南石油大学石油与天然气工程专业硕士学位,现为中联煤层气有限责任公司董事长、党委书记、高级工程师,主要从事油气田开发及生产管理工作。Email:liujzh@cnooc.com.cn
  • 基金资助:
    中海石油(中国)有限公司科技重大专项(CNOOC-KJ135ZDXM40)资助。

Abstract: As an important alternative energy in the unconventional oil-gas field, coalbed methane (CBM) has enormous potential. The deep coal seams are developed on a large scale in Ordos Basin. However, CBM exploration and development is restricted due to complex geological and engineering conditions in the eastern margin of the basin. This paper is a case study of Linxing-Shenfu block in Ordos Basin. The scientific issues such as geological characteristics of sedimentation and hydrocarbon accumulation, production characteristics, and fracturing mining technology regarding deep coal seams in Ordos Basin are explored based on a large amount of drilled data, core analysis data, and drainage dynamic data. The results show as follows:both semi-bright and semi-dark coal in deep coal seams are developed, dominated by primary structure; the deep CBM is characterized by high gas saturation, sufficient reservoir energy, and favorable coal body structure; two core indicators for evaluating sweet spot area of deep CBM have been determined, i.e., resource availability (coal reservoir energy) and feasibility of fracturing (structure, vertical fracture zone, stress difference between roof and floor and coal seam); a new method has been established by quantification of fractal theory and numerical simulation to characterize the complexity of fractures, forming a horizontal well segmented extreme volume fracturing technology system featured with "dense cutting+large displacement+combined proppant+pre-positioned acid+variable viscosity slickwater"; two gas production control parameters (gas saturation and gas content) have been determined for deep coal seams, and production wells can be divided into three categories based on the characteristics of gas production, i.e., self-flowing after pressure, immediate gas production after discharge, as well as conventional discharge and production. The large-scale efficient development of deep CBM needs to tackle a number of fundamental problems. Great efforts should be paid on making a breakthrough in hydrocarbon expulsion and occurrence process of deep coal seams, determining the boundary conditions for the enrichment area of sweet spots, studying the mechanical properties of deep coal seams and volume transformation. Moreover, it is required to continuously strengthen the integrated technical management of geology, engineering, drainage and production, innovate the enterprise-locality integration and management patterns, and keep improving the assessment of the ultimate recoverable reserves of a single well, so as to achieve the large-scale beneficial development of deep CBM.

Key words: eastern margin of Ordos Basin, deep coalbed methane, major breakthrough, technological innovation, production characteristics, challenges and countermeasures

摘要: 煤层气作为非常规油气领域的重要接替能源其潜力巨大,其中,鄂尔多斯盆地深部煤层发育规模良好,但盆地东缘复杂的地质和工程条件制约了煤层气勘探开发的进程。以临兴—神府区块为例,基于已钻井资料、岩心分析资料及排采动态数据,对鄂尔多斯盆地深部煤层沉积和成藏地质特征、生产特征及压裂开采工艺等科学问题进行了探讨。研究结果表明深部煤层中半亮煤、半暗煤均有发育,以原生结构为主;深部煤层气藏具有含气饱和度高、储层能量足、煤体结构有利的特点;厘定了深部煤层气的"甜点区"评价的两个核心指标,即资源性(煤储层能量)和可压性(构造、垂向裂隙带、顶底板与煤层应力差);建立了分形理论定量化+数值模拟表征裂缝复杂程度的新方法,形成了"密切割+大排量+组合支撑剂+前置酸+变黏滑溜水"极限体积水平井分段压裂技术体系;落实了深部煤层的两个产气量控制参数(含气饱和度、含气量),根据产气量特征可将生产井分为压后自喷、排采即见气和常规排采3类。深部煤层气的规模效益开发亟需攻关深部煤层的排烃赋存过程、确定"甜点"富集区的边界条件、研究深部煤层的力学性质与体积改造等基础问题,持续强化地质—工程—排采一体化技术管理,创新企地融合和管理模式,持续提高单井的评估最终可采储量,实现深部煤层气规模效益开发。

关键词: 鄂尔多斯盆地东缘, 深部煤层气, 重大突破, 技术创新, 生产特征, 挑战与对策

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