【作者】 姜勇；

【导师】 梁冰；

【作者基本信息】 辽宁工程技术大学 ， 流体力学， 2011， 硕士

【摘要】 煤炭是我国推动经济发展的主体能源,瓦斯是煤矿安全生产的主要威胁,同时也是我国优质高效的洁净能源。我国大多数煤层属于低渗透煤层,尤其是近年来煤层开采进入深部区,瓦斯含量、瓦斯压力随着地应力增大而增大,突出危险性越来越严重,迫切需要做好瓦斯治理工作,瓦斯抽采技术是提高低渗透单一煤层瓦斯抽采效果的重要途径之一。本文从低渗透煤层结构特征研究出发,以低渗透煤层孔隙裂隙结构为对象,基于地应力、瓦斯压力和孔隙裂隙结构三方面分析其对煤层透气性的影响。针对低渗透煤层瓦斯特性,分别从吸附、解吸、扩散、渗流四个方面论述了瓦斯赋存运移机理。基于相似实验理论,利用相似材料模型模拟低渗透煤层,经高压水射流割缝,采用压力盒预埋的方式监测割缝前后模型内不同位置应力变化,结合位移计的位移变化和模型渗透率变化,数据分析割缝前后模型应力、位移、渗透率的变化规律,为揭示低渗透煤层割缝增透机理提供实验依据。总结分析实验研究所得结论,基于煤体结构在承压状态下割缝卸压,缝槽两侧煤体发生变形破坏,应力重新分布后处于复杂应力状态,上部煤体因缝槽卸压而发生向下位移,缝槽周围受破坏产生破碎区,煤层内瓦斯出现分区域的非线性渗流特点,以此从割缝煤层结构、力学机理和瓦斯非线性渗流三个方面揭示割缝增透机理。更多还原

【Abstract】 Coal is the main energy in our country to promote economic development. Gas is the major potential threat during coal mine production, but meanwhile is the high-quality and efficient clean energy. In our country, most of the coal bed is low-permeability. Especially in recent years, because of the deepening exploitation of the coal bed, gas contents and pressure is increasing with the increased Ground Stress, thus the prominent risk gets larger which needs the good gas control technology urgently. The gas drainage technology is one of the important ways to improve the low-permeability single coal bed gas drainage effect.This paper starts from the research of structure characteristic of low-permeability coal bed; with low-permeability coal bed pore fracture structure as objects, based on the aspects of in-situ stress, gas pressure and the pore structure, analyzes the influence on permeability coal bed. Aiming at characteristics of low-permeability coal bed gas, this paper dissertates the gas storage migration mechanism from the aspects of desorption, desorption, diffusion, seepage respectively.Based on the similarity theory, using the similar material model to simulate low-permeability coal bed, by high pressure water jet cutting, using pressure box embedded way to monitor stress variation in model at different sites before and after cutting, combining the displacement of the displacement meters and model permeability change, data analysis of the model stress, displacement, permeability variation rule before and after cutting, to provide experiment basis for enhancements mechanism of low-permeability coal bed.By analyzing experimental research, this paper gets the conclusion that based on the structure of coal bed cutting load relief under the status of confined, the coal on the both sides of slot will be deformation. The stress will be the complex status after stress redistribution. The upper coal displace downward due to slot pressure relief, the break zone produced around slot, coal bed gas appears the nonlinear seepage characteristics of partition area. From the aspect of cutting coal bed structure, dynamic mechanism and gas nonlinear seepage to reveal cutting permeability enhancements mechanism.更多还原