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西北地区侏罗系中、下统含煤盆地多 ,煤层累计厚度 15 .15～ 16 9.2m ,一般厚度 30～ 80m ,埋藏深度2 0 0 0m以浅区残留面积约 90 0 0 0km2 左右 ,煤层气资源总量达 74 5 6 4 .6 5× 10 8m3 ,有着十分广阔的煤层气勘探开发前景。研究认为 ,煤岩中镜质组含量较高 ,灰分含量较低 ,煤级以长焰煤为主 ,有利于储层中割理和裂隙的生成 ,增加储层渗透性。导致煤层含气性变化的主要地质因素是煤层埋藏深度和演化程度 ,随着埋藏深度的增大和煤级的增高 ,含气量有逐渐增加趋势。通过对比煤层含气性、资源量和煤层气赋存地质条件认为 ,煤层气资源勘探开发前景有利区有吐哈和焉耆含煤区 ;较有利区有准南、准北、准东、伊犁、塔北、尤尔都斯、羊不拉克和三塘湖含煤区 ;不利区有乌恰、昆仑、阿尔金、塔东、柴北、祁连和靖远含煤区

Research on the Prospect of Coal-bed Methane Resources in Jurassic in Northwest China

??There are many Middle Early Jurassic coal bearing basins in Northwest China.The cumulative thicknesses of coal-beds are 15.15??169.2 m,general thicknesses 30??80m and the total coal-bed methane resource extent is up to 7456465 ×10⁶m³ calculated according to the remnant area(about 90 000 km²)with burial depths of less than 2000m,which shows a vast range of prospects for coal-bed methane exploration and development.The research shows that in coal rocks,the vitrinite content is relatively high,the ash content is relatively low,and long flame coal occupies the leading position,which is beneficial to the formation of cleats and fractures to increase reservoir permeability.The principal geological factors of causing the change in coal-bed methane content are the burial depth of coal-beds and the degree of their evolution.Along with the increase in burial depth and the rising of coal rank,the methane content has the trend of being gradually enlarged.Through contrasting the methane content and resources and the geological conditions of coal-bed methane methane occurrence,it is considered that the advantageous coal-bed methane exploration and development areas include Tuha and Yanqi coal bearing regions;the relative advantageous areas include Zhunnan,Zhunbei,Zhundong,Yili,Tabei,You'erdusi,Yangbulake and Santanghu coal bearing regions;and the disadvantageous areas include Wuqia,Kunlun,A'erjin,Tadong,Chaibei,Qilian and Jingyuan coal bearing regions.