煤系非常规天然气资源特征及分隔合采技术

Resources characteristics and separated reservoirs' drainage of unconventional gas in coal measures

煤系为煤层气、页岩气、致密砂岩气多层叠置的储层群(青海木里煤田侏罗纪煤系上部还有天然气水合物矿层),海陆过渡相煤系以多层叠置页岩气与煤层气储层为主,陆相煤系以多层叠置煤层气与致密气储层为特色;煤-泥-砂结构系统使煤系内经常出现煤层气和页岩气的混合储层。中国煤系中煤层气资源量约为36.8×10^(12) m^3;页岩气、致密气资源量分别约为32×10^(12) m3和20×10^(12) m^3(未包括东北地区)。煤系"三气"单独开发经济效益不明显;煤系"三气"具有地面卸压带抽采和煤矿井下穿层钻孔抽采的便利条件;通过增加悬挂套管和连通管,文中设计了煤系"三气"原位分隔合采工艺技术。

Coal measures area group of multiply superposed reservoirs which contain combed methane, shale gas and tight sandstone gas（ there is also a gas hydrate reservoir lying on the Jurassic coal seam in the Mull coalfield, Qinghai Province） ; the transitional coal measures mainly contain eoalbed methane and shale gas; the inland coal measures feature coalbed methane and tight sandstone gas; the mixed reservoir containing coalbed methane and shale gas often appears in coal measures owing to the coal-mud-sand structure system. In China, coalbed methane resources are about 36.8 X 1012 m3 ; shale gas and tight gas resources are about 32 X 1012 ma and 20 N 10tz ma respectively in coal measure（not including the Northeast China）. The economic benefit of developing three kinds of gas individually is not obvious; but it has some convenient conditions, such as stress relief with three kinds of gas drainage by vertical surface wells and by cross- measures boreholes in underground mine. Technology of separated reservoirs＇ drainage was designed by adding hanging case and communicating tubes.