关键词: 煤层气, 产能, 渗透率, 含气饱和度, 开发

Abstract:

The gas modecules in coalbed methane are in a dynamic absorption-desorption equilibrium under coalbed pressure. The gas can be produced through desorption, diffusion, seepage as the reservoir is opened and then the pressure is reduced. This paper, according to production data, analyzes the influences of permeability, gas saturation, critical desorption pressure and fracture halflength on production. China’s coal beds bear features of low pressure, low seepage, and low saturation, leading to a poor drive in reservoir, which is hard in gas desorption and seepage under natural conditions; hence, an applicable way shall be taken. Compared with the natural gas reservoir, the coalbed methane will easily be destroyed while mining. Some reservoir protective technologies are vital for production during underbalanced drilling and nitrogen foam fracturing. Coalbed reservoirs vary with areas, where corresponding methods shall be studied in applicability and economy.

Key words: coalbed methane, production capability, permeability, gas saturation, development