低透气性高瓦斯煤层水力冲孔增透技术研究

发布时间：2018-05-30 09:35

本文选题：水射流 + 水力冲孔　；参考：《安徽建筑大学》2013年硕士论文

【摘要】：煤炭作为我国的基础能源，在其生产过程中煤与瓦斯突出是制约煤炭安全开采的主导因素，因此保证煤炭安全生产是保障实现我国民经济和社会经济快速可持续发展的先决条件。目前针对我国不具备开采保护层的条件下的煤层透气性较低、煤层软、煤与瓦斯突出危险性大的特点，主要采用水力压裂、水力挤出、煤层注水等区域性防突措施。相比之下，作为区域性防突新措施水力冲孔强化抽采瓦斯技术具有安全性高、周期性短、操作简单等优点，在全国各矿区都取得了较好消突效果，但由于地质条件限制，在参数设计、设备选型、冲出煤量控制等没有形成广泛推广的应用技术，因此对水力冲孔强化抽采瓦斯技术有待进一步系统研究。本文主要针对透气性低、煤层软和无保护层开采条件的煤层条件，以潘二煤矿11223西二工作面为试验地点，通过理论分析、数值模拟和现场试验相结合的方法，从以下三方面内容研究：（1）水力冲孔作用机理的研究依据水射流动力学特性，研究水射流对煤体的破坏过程，，分析了水力冲孔的破煤机理、以及影响射流切割煤体的主要因素，并由煤与瓦斯突出机理的阐述，引出水力冲孔后的消突作用。（2）水力冲孔增透效果数值模拟基于试验现场条件，建立水力冲孔后周围煤体应力与瓦斯流动的数学模型，理论计算冲孔后周围煤体应力有效影响范围可达孔径的5倍（以初始应力变化幅度小于5%为指标）；并在模拟基础上分析了水力冲孔后不同钻孔周围煤体瓦斯压力分布、消突效果，模拟分析孔径为0.7m的孔径有效影响半径可达4.5m,并针对不同孔径条件模拟确定了有效抽采半径，由此优化水力冲孔钻孔布置方法，指导现场实践。（3）水力冲孔技术现场试验及效果依据数值模拟结果，对水力冲孔区域预抽瓦斯消突技术现场试验进行了分析:潘二煤矿11223西二工作面底板巷水力冲孔区域预抽瓦斯后掩护下顺槽掘进试验，着重分析水力冲孔后煤体预抽瓦斯效果以及煤体透气性变化，透气性由（0.19→1.71）m~2/(MPa~2.d)，瓦斯衰减系数仅为原来的1/3，提高瓦斯抽采量，消突效果检验后进行煤巷掘进，掘进期间通过对突出危险性指标和瓦斯涌出参数的分析，验证穿层钻孔区域预抽瓦斯消突技术的有效性;结果表明，实施水力冲孔后更能促进煤体裂隙发育成和范围，且增透和消突效果较好，具有很好的应用前景。
[Abstract]:Coal and gas outburst are the leading factors restricting the safety of coal mining in the process of production, so ensuring the safe production of coal is a prerequisite for ensuring the rapid and sustainable development of our national economy and social economy. At present, the coal seam is breathable under the condition that the mining protection layer is not available in China. The characteristics of low sex, coal seam soft, coal and gas outburst are very dangerous, mainly using hydraulic fracturing, hydraulic extrusion, coal seam water injection and other regional anti outburst measures. In comparison, as a new method of regional outburst prevention, hydraulic punching and mining gas extraction technology has the advantages of high safety, short periodicity, simple operation and so on, which have been obtained in all mining areas in China. But because of the limitation of the geological conditions, there is no widely popularized application technology in the parameters design, equipment selection and the control of the discharge of coal. Therefore, the technology of strengthening the gas extraction of the hydraulic punching hole needs to be further studied.
This paper mainly aims at the coal seam conditions of low permeability, soft and unprotected coal seam mining conditions, taking the 11223 west two working face of Pan two coal mine as the test site, through theoretical analysis, numerical simulation and field test method, from the following three aspects: (1) research on the mechanism of hydraulic punching action
According to the mechanical characteristics of water jet flow, the damage process of water jet to coal body is studied, the mechanism of coal breaking and the main factors affecting the jet cutting coal body are analyzed, and the mechanism of coal and gas outburst is expounded, and the elimination effect after hydraulic punching is elicited. (2) numerical simulation of the effect of hydraulic piercing penetration enhancement
Based on the test site conditions, a mathematical model of the stress and gas flow of the surrounding coal is established after the hydraulic punching. The theoretical calculation of the effective influence of the stress on the surrounding coal is 5 times that of the pore diameter (the initial stress variation is less than 5%), and the gas pressure of the coal body around the holes after the hydraulic punching is analyzed on the basis of the simulation. The effective influence radius of the aperture of 0.7m is simulated and analyzed by the force distribution, the effective radius of the aperture is 4.5m, and the effective extraction radius is determined according to the different aperture conditions. Thus the layout method of the hydraulic punching hole is optimized and the field practice is guided. (3) field test and effect of hydraulic punching technology.
According to the numerical simulation results, the field test of the pre extraction of gas outburst in the hydraulic punching area was analyzed. The experiment was carried out in the hydraulic punching area of the 11223 west two working face of the Pan Er coal mine, which was pre pumped under the cover of the hydraulic punching area, and the coal body pre pumping and the permeability change of the coal body after the hydraulic punching were analyzed. The air permeability was (0.19). 1.71) m~2/ (MPa~2.d), the gas attenuation coefficient is only the original 1/3, the gas extraction quantity is increased, the coal roadway driving is carried out after the elimination effect inspection. Through the analysis of the outburst risk index and gas emission parameters during the excavation, the effectiveness of the gas outburst elimination technology in the perforated borehole area is verified. The results show that the hydraulic punching can be more promoted after the hydraulic punching. The fracture and development of the coal mass are good and have good application prospects.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TD713

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