【作者】 张燕朋；

【导师】 张子敏； 张玉贵；

【作者基本信息】 河南理工大学 ， 安全技术及工程， 2011， 硕士

【摘要】 中国是煤炭工业大国,瓦斯资源非常丰富,但煤层瓦斯储层普遍属于低渗透储层,且传统的煤层瓦斯抽采方法的采收率低,采气时间较长,经济效益较差。煤层瓦斯抽采率低的直接后果是煤矿瓦斯灾害频发、采煤效率低、环境污染等。面对我国绝大多数煤层渗透率较低的特点和煤矿瓦斯抽采率低的现状,建议采用注气驱替煤层瓦斯,来提高煤层瓦斯的产气速度与采收率。注气抽采瓦斯被认为是有较好前景的煤层瓦斯抽采技术。本文应用瓦斯地质学、多相气体渗流和扩散、固体力学、数值分析等理论在总结前人已有的研究结果的基础上,根据瓦斯储层特性,将煤层抽象为双孔隙度单渗透率的双重介质模型,研究了瓦斯解吸、扩散、渗流机理,并在研究注气抽采瓦斯机理的基础上,建立了双重介质煤层注气抽采模拟的二维模型,并对瓦斯流动特征变化进行了分析。主要取得的研究成果和认识如下:(1)结合我国低渗煤层的实际,注气瓦斯抽采是一种非常有效的手段,能够在不伤害瓦斯储层的前提下提高瓦斯抽采效果,较水力压裂效果好;(2)在瓦斯抽采的影响因素中,瓦斯压力梯度和浓度梯度是瓦斯解吸的重要因素,使瓦斯压力梯度保持在一定范围,才能使更多的瓦斯解吸出来;(3)建立了低渗煤层注气抽采瓦斯的模型,考虑了无注气抽采条件和注气抽采瓦斯条件两种条件,证明了注气可以提高瓦斯抽采效果,并分析了注气对瓦斯压力和浓度的影响。本文经过数值模拟表明注气抽采瓦斯措施对低渗煤层具有较好的效果。更多还原

【Abstract】 China is a big coal industry country ,the coal-bed methane resources very rich,however,coal-bed methane reservoirs are low-permeability reservoir,which is different from the U.S coal-bed geological conditions,and the traditional coalbed methane exploitation methods are lower productivity,longer recovering period and poor economic are poorer.The direct consequences of low recovery ratio of coal-bed methane are gas disaster-prone,inefficient mining,resources waste and environmental pollution. based on the low permeability characteistic of most coal-bed and corrent ststus of low recovery ratio of coal-bed methane in china,the corbon dioxide enhanced coal-bed methane technology has been suggested for the purpose of enhancing coal-bed mehtane recovery ratio.Gas injection and methane drainage technology is considered a better prospect coal-bed methane exploitation technology.This paper applied the gas geology, multiphase gas seepage and diffusion, solid mechanics, numerical analysis theory in the summary of the existing research results of predecessors, based on the gas reservoir property, will double porosity coal abstracted as dual medium model of single permeability, studies the gas desorption, diffusion, percolation mechanism, and in research note gas extraction mechanism is established, on the basis of the dual medium coal seam gas injection extraction simulation of two-dimensional model of gas flow characteristic, and the changes were analyzed. Main obtains the research achievements and known as follows:(1) In combination with the actual, low permeability coal seam gas extraction gas injection is a kind of very effective means to be hurting the gas reservoir premise improve gas extraction effect, a hydraulic fracturing effect is good; (2) In the gas extraction in the influential factors, gas pressure gradient and concentration gradient is the important factors, gas recorery gas pressure gradient to remain in a certain range, can make more gas recorery out. (3) Establish a low permeability coal seam gas extraction gas injection, considering the model, without note gas extraction conditions and note gas extraction gas conditions, proved two conditions can improve gas injection gas extraction, and analyzes the effect of gas gas injection pressure and concentration of influence. Note gas extraction coal gas measures aiming at characteristics of low permeability and has a good effect.更多还原