吐哈盆地低煤阶煤层气地质特征与成藏控制因素研究

Geological Characteristics of Coalbed Methane and Controlling Factors of Accumulation in the Tuha Coal Basin

我国低煤阶煤层气资源丰富,气煤以下的低煤阶煤层气资源量15.13×1012m3。迄今为止尚无成功开发先例,地质成藏基础研究亟待加强。论文通过对吐哈盆地煤层气成藏条件、成藏特征分析,探讨了地质构造、聚煤作用、煤系特征、生物气形成与保存等低煤阶煤层气成藏控制因素,初步确定了吐哈盆地煤层气成藏类型及其分布特征,把吐哈盆地煤层气成藏模式划分为盆内凹陷成藏模式、盆缘陡坡成藏模式和盆缘缓坡成藏模式3种类型,根据成藏过程的匹配特征把煤层气藏类型划分为储-逸型低压逸散式、储-运-逸型运移储集式两种类型,该划分方案有助于指导低煤阶煤层气成因研究与资源勘探开发。

China is abundant in low-rank coalbed methane resources,with a total reserve of over 15.13 trillion cubic meters.Till now,no successful production has been made,and thus basic geological research should be strengthened.Based on the conditions and characteristics of coalbed gas reservoirs in the Tuha basin,this study discussed the geological structures,coal accumulation,coal series features,biogenic gas preservation,etc;determined the type of coalbed methane reservoir in the Tuha basin and distribution pattern;and finally divided the coalbed gas into three types：basin depression reservoir,basin margin steep and mild slope reservoir.Matching characteristics of reservoir formation suggests two reservoir types for low rank coalbed gas：reservoir forming-dissipation and forming-migration-dissipation,which will be useful for guiding the research of low rank coalbed methane genesis and exploration of the coalbed methane.