基于卸压煤层气开发的构造煤储层孔渗特征与类型划分——以淮南矿区为例  

Poroperm characteristics and classification of tectonic coal beds for pressure-relieved methane exploitation:a case study on Huainan mining area

作　　者：吴国代[1,2,3] 桑树勋[4] 程军[1,2,3] 柳天均[1,2,3] 黄华州[4] 任波[4] 

机构地区：[1]重庆地质矿产研究院国土资源部页岩气资源与勘查技术重点实验室,重庆400042 [2]重庆地质矿产研究院重庆市页岩气资源与勘查工程技术研究中心,重庆400042 [3]油气资源与探测国家重点实验室重庆页岩气研究中心,重庆400042 [4]中国矿业大学资源与地球科学学院,江苏徐州221116

出　　处：《石油学报》2013年第4期712-719,共8页Acta Petrolei Sinica

基　　金：国家高技术研究发展计划(863)项目(2007AA06Z220);教育部重大科学技术项目(307014)资助

摘　　要：在淮南矿区卸压煤层气地面开发取得积极进展的背景下,应用扫描电镜和汞注入法对淮南矿区构造煤样进行孔裂隙测试,结合井下煤层透气性和试井渗透率测试数据,探讨了构造煤储层孔渗特征。对比分析了卸压煤层气开采现场测试渗透率变化差异,揭示了构造煤卸压开采条件下影响煤层渗透率变化的影响因素及煤体结构差异对煤储层改造的控制作用,提出了构造煤储层类型划分方案。研究表明:随着构造变形的增强,煤中外生孔裂隙规模增大,孔容、中值孔径、孔隙度等参数增大,煤储层渗流孔含量与构造变形呈正相关,但地层条件下构造煤储层的渗流性受储层压力、煤体结构、地下水等因素控制。构造煤储层特性决定了当前原位煤层气开发技术的不可行性;而卸压煤层气开采有效解决了构造煤储层渗透率低、压力传递困难以及压裂改造效果差等技术难题,卸压开采对煤储层的改造导致的"卸压增透增流"效应主要受煤体结构控制。煤体变形越强,改造效果越好,基于不同煤体结构构造煤储层中渗流孔的含量与改造效果的一致性,认为糜棱煤是卸压煤层气开发的优质储层,碎粒煤是较优质储层,碎裂煤和鳞片状煤是一般储层,原生结构煤是不利储层。Against the background of progresses made in the ground exploitation of pressure-relieved methane in the Huainah mining area, we tested poricidal fracture systems of tectonic coals from this mining area by SEM and mercury injection, and discussed po- roperm characteristics of tectonic coal beds based on well-testing data of penetrability and permeability of borehole coal seams. A comparative analysis of differences in permeability variations measured in practical exploitation of pressure-relieved methane was per- formed and it revealed influencing factors of permeability variations of tectonic coals under conditions of pressure-relieved exploitation and control effects of the coal texture difference on coal bed reworking, by doing so, a classification method of tectonic coal beds was introduced. The result indicates that with increasing structural deformation, the scale of exogenously poricidal fractures in coals in- creases, and correspondingly other parameters including pore volume, median aperture and porosity increase as well. The seepage pore content of coal beds is positively correlated with structural deformation, while seepage properties of real tectonic coal beds are controlled by pressure, coal texture, underground water, etc. Characteristics of tectonic coal beds make development techniques of in-situ CBM infeasible, while some problems encountered in CBM development, such as low permeability, difficulty in pressure transmission and poor effects of fracturing of coal beds, can be solved with techniques of pressure-relieved methane exploitation, The effect of ＂increasing permeability and fluidity by pressure relief＂ caused by reworking of coal beds in pressure-relieved methane ex- ploitation is controlled mainly by coal textures,i, e. the stronger the coal deformation, the better the reworking effect. Based on the consistency of the seepage pore content of different coal textures in coal beds with the reworking effect, a mylonitie coal is considered to be a high-quality coal bed for pressure-relieve

关 键 词：构造煤储层 卸压煤层气开采 煤体结构 渗流孔 渗透率 

分 类 号：TE112.115[石油与天然气工程—油气勘探]