摘要:
为掌握近距离煤层群叠加开采的应力-裂隙-瓦斯渗流规律，构建近距离煤层群煤与瓦斯高效共采技术体系及动态评价模型，以山西吕梁沙曲矿区为研究对象，采用物理相似模拟、超声波试验及SF6示踪气体现场监测相结合的研究方法，分析了沙曲矿区近距离煤层群煤层气资源的赋存特点，探究了沙曲矿区近距离煤层群多次扰动下煤岩损伤变量随应力的变化规律，建立了Boltzmann煤岩损伤方程，得出了沙曲矿区近距离煤层群叠加开采条件下采动应力演化-裂隙发育-瓦斯运移规律。研究结果表明：沙曲矿区煤层的孔裂隙结构特征不利于瓦斯运移，在近距离煤层群叠加开采条件下二次采动对于覆岩应力场和裂隙场的影响并非简单的效果叠加，而是“1+1＞2”的影响效果，下覆煤层在叠加开采下产生了贯穿型裂隙，并在其周围衍生了大量的次生裂隙，为煤层瓦斯运移提供了优势通道；根据沙曲矿区煤-气共采不同阶段的时空条件和消突要求，分区分级优选并集成了近距离煤层群煤与瓦斯共采技术体系，即在规划区采用多种地面井规模化多煤层长时间预抽煤层气，在准备区采用多分支水平井井孔定向对接共采和保护层开采+底抽巷定向钻孔群抽采，在生产区采用大采高沿空留巷共采及大直径定向钻孔群共采技术；通过分析煤与瓦斯共采的影响因素，提出了近距离煤层群煤与瓦斯共采动态评价指标体系，建立了贝叶斯煤与瓦斯共采评价模型，实现了对沙曲矿区煤与瓦斯共采效果及矿井部署合理性的评价，得出沙曲一矿煤与瓦斯共采动态合理性概率为0.65、共采合理性等级为“较为合理”；最后阐述了近距离煤层群煤与瓦斯共采技术存在的关键问题，展望了近距离煤层群煤与瓦斯共采技术未来发展方向。
Abstract:
In order to grasp the law of stress fracture gas seepage in the superposition mining of close seam group, and to construct the technical system and dynamic evaluation model of high efficiency Simultaneous Extraction of coal and gas in close distance coal seam, taking Shaqu mining area as the research object, the research method of combining physical similarity simulation, ultrasonic test and SF6 tracer gas field monitoring is adopted, Analyzing the occurrence characteristics of coalbed methane resources in the short distance coal seam group of Shaqu coal mine, which is characterized by "gas overrun in the north wing and gas outburst in the South Wing", Based on the exploration of the variation law of the damage variable of coal and rock with the stress under the multiple disturbance of the close seam group in Shaqu mine, the Boltzmann damage equation of coal and rock is established, and the characteristic law of mining stress evolution fracture development gas migration under the condition of superposition mining of the close seam group in Shaqu mine is obtained. The results show that the characteristics of pore and fracture structure of Shaqu coal seam are not conducive to the migration of gas. The influence on the stress field and fracture field of overburden under the condition of close distance coal seam superposition mining is not simple effect superposition, but the effect of "1 + 1 > 2" appears, and the overburden coal seam produces through type fracture under the superposition mining, and large cracks are derived around it The amount of secondary fractures provides the dominant channel for the gas migration in coal seam in time; and according to the time and space conditions of different stages of coal and gas simultaneous extraction in Shaqu mine and the requirements of outburst control, the technical system of simultaneous extraction of coal and gas in short distance coal seam group is formed, that is to say, in the planning area, a variety of surface wells are used for large-scale and long-term pre extraction of coalbed methane. In the preparation area, multi branch horizontal wells are used for directional joint mining and protective layer mining + bottom extraction roadway for directional drilling group mining. In the production area, large mining height along goaf and large diameter directional drilling group mining technologies are used for simultaneous extraction of coal and gas; by analyzing the influencing factors of simultaneous extraction of coal and gas, the dynamic evaluation index system of simultaneous extraction of coal and gas in short distance coal seam group is put forward, the Bayesian evaluation model of simultaneous extraction of coal and gas is established, and the evaluation of simultaneous extraction effect of coal and gas and the rationality of mine deployment in Shaqu mine are realized, that is , the dynamic rationality probability of coal and gas simultaneous extraction in Shaqu No.1 mine is 0.65, and the rationality grade of simultaneous extraction of coal and gas is relatively reasonable; At last, the bottleneck of simultaneous extraction technology of coal and gas in close seam group is discussed, and the future development direction of simultaneous extraction technology of coal and gas in close seam group is prospected.
百度学术
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