滇东-黔西地区煤层气构造特征

STRUCTURAL CHARACTERISTICS OF COALBED METHANE IN EAST YUNNAN AND WEST GUIZHOU AREA

煤层气在成煤过程中生成 ,并主要以煤层为储层的非常规天然气 ,通常甲烷组分占绝大部分 ,故亦称为煤层甲烷。甲烷以分子吸附状态 ,赋存于煤基质的巨大内表面上。滇东 黔西地区煤层气资源丰富 ,开发煤层气资源 ,为该区的经济腾飞将起到极大的推动作用。煤层气的勘探开发 ,须要研究形成煤层气的聚煤盆地的地质构造。地壳地质和深部构造是一个统一的整体。通过该区重力、磁力异常、TM遥感影像、古今地应力场研究 ,滇东 黔西地区 ,莫霍面由东向西呈阶梯状下降 ,上地壳由东向西增厚 ,沉积岩与基底具有明显的继承性 ,在晚二叠世为西高东低的陆相、海陆交替相和浅海相的沉积环境 ,形成巨大的聚煤盆地 ,经各期构造变动 ,成为现今众多的残留煤盆地。

The coalbed gas is an unconventional gas resulted from coalification and mainly in a coalbed gas reservoir. It is also called coalbed methane because of the methane being a predominate member. The methane mostly exists as a molecularly absorbed phase within the coal matrix. Coalbed gas resources are very rich in East Yunnan and West Guizhou area. And to develop them can promote the economic prosperity of this area. In order to the exploration and development, it is necessary to know the geologic structure of the coal basin where the coalbed gas forms. The crustal geology and the deep structure are integrated. The study on the gravity, magnetic anomaly, TM remote sensing image and underground stress field characteristics of this area shows that the Mohorovich discontinuity lowers and the upper crust thickens from east to west and the sedimentary rock has evident inheritance with the basement. In Permian, a large coal basin was formed in the depositional environment of land, land marine and epicontinental facies from west to east. After a long time of tectonic activities, a lot of remnant coal basins have been formed in it.