煤层气产能影响因素及开发技术研究

煤储层中气体分子在承压状态下处于吸附-解吸的动态平衡，随着产层打开和压力降低，气体通过解吸、扩散、渗流产出，形成产能。笔者结合生产井数据，分析了渗透率、含气饱和度、临界解吸压力和压裂缝半长对产能的影响。中国煤层具有低压、低渗、低饱和度等特点，致使储层驱动能量不足，在自然条件下气体解吸、渗流困难，所以必须采用有效的开发增产技术。与常规天然气储层相比，煤层气储层更容易受到损害，在进行开发时采取欠平衡钻井、氮气泡沫压裂等储层保护增产技术对于单井产量的提高至关重要。各地区煤储层特征差异显著，在开发时要对不同的开发手段进行适用性与经济性研究。

FACTORS AND DEVELOPMENT TECHNOLOGY OF COALBED METHANE PRODUCTION CAPABILITY

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.