煤及煤层气储层导电特性研究综述与展望

随着人类对天然气资源需求的剧增,煤层气勘探开发已备受业界重视.煤层气勘探开发的诸多技术均移植于常规天然气.常规天然气储层的含气饱和度与电阻率间具有良好的相关性.对于煤层气储层,煤层含气量与电阻率间是否具有相关性、其影响因素主要有哪些,对电阻率预测煤层含气量至关重要.本文翔实调研了国内外煤及煤层气储层导电性研究的相关文献,系统总结了煤体结构、煤的变质程度、温度及水分等对煤体导电性的影响特征,并细致梳理了含气煤储层吸附和解吸过程中电阻率变化规律.系统总结得知,现有研究成果多集中在煤体导电性的研究方面,煤层含气量与煤储层导电性间的内在定量关系尚不清晰.借助于煤岩样标定电阻率测井,进而来分煤阶、分煤体结构来研究煤层气储层导电性是本领域发展的趋势.

Review and prospect of study on conductive properties of coal and CBM reservoirs

With the increasing demand for natural gas resources around the world,the exploration and development of CBM has been highly valued by the industry.Many technologies of CBM exploration and development are transplanted to conventional gas.There is a good correlation between gas saturation and resistivity of conventional natural gas reservoirs.For CBM reservoir,whether there is correlation between coal seam gas content and resistivity,and what are the main influencing factors,it is very important to resistivity prediction of Coal-bed gas content.In this paper,the relevant literature on the study of the electrical conductivity of coal and CBM reservoir at home and abroad is fully investigated,and the influence characteristics of coal structure,degree of coal metamorphism,temperature and water on the electrical conductivity of coal bodies are systematically summarized,and the variation rules of the electrical resistivity of coal reservoirs in the process of gas-containing coal bodies,adsorption and desorption process are carefully combed.It is concluded that the existing research results are mainly focused on the study of coal conductivity,and the intrinsic quantitative relationship between CBM and conductivity of coal reservoir is still unclear.Therefore,it is the development tendency of this field to study the conductivity of CBM reservoir by means of coal core calibration resistivity logging,and then by dividing coal rank and coal structure.