摘要
煤层气含量是煤层气资源评价、开发部署和经济评价的重要指标,通过大量实验分析,对卡拉哈里盆地XX区块煤层气含量主控因素进行研究。结果表明,煤岩有机质显微组成中镜质组经历凝胶化作用、惰质组经历丝煤化作用,富含镜质组的煤岩具有较高生气量及较强吸附能力,富含惰质组煤岩的生气能力和吸附能力较差。煤阶控制煤层气生成、煤岩储层孔隙及割理发育,当镜质组反射率小于0.5%时,为生物气形成阶段,生气量小,煤岩原生孔隙发育,吸附能力差,煤层气含量低。当镜质组反射率为0.5%~4.0%时,煤岩有机质经历热降解和热裂解作用,生气量大;随着镜质组反射率的增大,煤岩微孔隙和割理增多、比表面积显著增加,含气量逐渐增大。当镜质组反射率大于4.0%时,煤岩微孔隙和割理减少、比表面积显著减小,煤层含气量减少。煤岩灰分含量与吸附能力呈负相关,煤岩灰分含量越少,吸附能力越强,煤层气含量越高。另外,煤层顶板岩性致密、渗透性差,煤层气含量相对较高;远离断层的煤层气保存条件相对较好,煤层气含量相对较高。
Coalbed methane content is an important indicator of CBM resources assessment,development deployment and economic evaluation. By analyzing a large number of experiments,the main controlling factors of the coalbed methane content in Block XX of Kgalahari Basin were studied. The studies show that the vitrinite in organic macerals of coal experienced the gelation function and the inertinite experienced the silk-coalification function. The coal rich in vitrinite has higher methane content and stronger adsorption ability,while the coal rich in inertinite has lower methane content and weaker adsorption capacity. Coal rank controls the production of coal-bed methane and the development of coal reservoir pore and cleat. When the vitrinite reflectance(Ro)is less than 0.5%,a small amount of biogenic gas is generated and the primary pore is well developed in coal. The adsorption ability of coal seam is poor and the content of coalbed methane is low. When the Rovalue ranges from 0.5% to 4.0%,the organic matter experiences thermal degradation and thermal cracking,a large quantity of methane was generated. Along with the increasing of the Rovalues,the degree of micropores and cleats development in coal increase gradually as well as the specific surface and the gas content. When the Rovalue is above 4.0%,the degree of micropores and cleats development in coal decreases as well as the specific surface and the gas content. Coal ash isnegative correlated with coalbed methane adsorption capacity. When the coal ash content is less,the adsorption capacity is stronger and the coal bed methane content is higher. Good preservation condition can be achieved when the rock in coal seam roof is dense and low in permeability and the wells are far away from the fault,and thus the coalbed gas content is relatively high.
作者
杨显成
蒋有录
杨昕睿
张恒涛
YANG Xiancheng;JIANG Youlu;YANG Xinrui;ZHANG Hengtao(School of Geosciences,China University of Petroleum(East China),Qingdao City,Shandong Province,266580,China;School of Geosciences,Yangtze University,Wuhan City,Hubei Province,430100,China;Equipment Service ofBGP INC.,China National Petroleum Corporation,Renqiu City,Hebei Province,062552,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2018年第1期56-60,共5页
Petroleum Geology and Recovery Efficiency
基金
国家科技重大专项"渤海湾盆地深层油气地质与增储方向"(2016ZX05006-007)
关键词
煤岩
煤层气
镜质组
惰质组
含气量
卡拉哈里盆地
coal rock
coalbed methane
vitrinite
inertinite
coalbed methane content
Kgalahari Basin
