中国煤储层渗透率主控因素和煤层气开发对策

发布时间：2018-06-10 21:22

本文选题：煤层气 + 渗透率　；参考：《地质论评》2017年05期

【摘要】：我国煤储层渗透率比美国煤储层渗透率低1~2个数量级,低渗透率是制约我国煤层气勘探开发的主要因素之一,本文系统分析了我国煤储层渗透率的主控因素。研究表明,煤储层的渗透率主要受煤体结构、宏观裂隙以及割理/裂隙系统充填状况和现今地应力等因素的控制,适度构造变形产生的碎裂煤中因宏观裂隙发育导致其渗透率高于原生结构煤的渗透率,但强烈构造变形形成的碎粒煤和糜棱煤则使渗透率降低;割理/裂隙系统矿物充填和高应力不利于渗透率保存。在不同地区,控制煤储层渗透率的关键因素不同,针对性对策是煤层气开发的关键:针对复杂煤体结构,在压裂井层优选时要在煤体结构测井解释的基础上考虑避开糜棱煤;针对我国华北地区石炭—二叠系煤层割理/裂隙普遍以方解石充填为主的煤储层低渗透成因,建议探索和开发酸化压裂一体化储层增透技术;针对高应力和地应力类型在垂向上的转换,在压前搞清应力强度和类型的基础上,控制水力压裂隙高度以避免沟通煤层围岩含水层;针对煤储层的应力敏感性和高应力状态,建议采用逐级降压制度,以提高单井的累计产气量。
[Abstract]:The permeability of coal reservoir in China is 1 ~ 2 orders of magnitude lower than that in the United States. Low permeability is one of the main factors restricting the exploration and development of coal bed methane in China. This paper systematically analyzes the main controlling factors of coal reservoir permeability in China. The results show that the permeability of coal reservoir is mainly controlled by coal body structure, macroscopic fracture, filling condition of cleat / fissure system and present ground stress, etc. The permeability of broken coal due to moderate tectonic deformation is higher than that of primary structural coal due to the development of macroscopic fracture, but the permeability of broken coal and chylarite formed by strong tectonic deformation is decreased. Mineral filling and high stress in cleat / fissure system are not conducive to permeability preservation. In different areas, the key factors to control the permeability of coal reservoir are different, the targeted countermeasures are the key to the development of coalbed methane: in view of the complex coal body structure, the coal body structure should be avoided on the basis of the coal structure logging interpretation in the optimum selection of fracturing wells; In view of the formation of low permeability in coal reservoirs of Carboniferous Permian coal seam cleats / fissures mainly filled with calcite in North China, it is suggested to explore and develop anti-permeability technology for acidified fracturing integrated reservoirs. In view of the vertical transformation of high stress and in-situ stress type, on the basis of making clear the stress intensity and type before compression, the height of hydraulic pressure fracture is controlled to avoid communicating with the surrounding rock aquifer of coal seam, and the stress sensitivity and high stress state of coal reservoir are also discussed. It is suggested to adopt step by step depressurization system in order to increase accumulative gas production of single well.
【作者单位】：中国石油大学(北京)地球科学学院;油气资源与探测国家重点实验室;中海石油(中国)有限公司非常规油气分公司;中联煤层气有限责任公司;中海石油(中国)有限公司非常规油气管理处;煤层气开发利用国家工程研究中心;中联煤层气国家工程研究中心有限责任公司;
【基金】：国家科技重大专项(编号:2016ZX05044)资助的成果~~
【分类号】：TD841;TE37

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