本煤层水压致裂增透范围分析

发布时间：2018-02-01 10:23

本文关键词： 本煤层水压致裂起裂方向裂隙长度裂隙扩展过程增透范围　出处：《采矿与安全工程学报》2015年04期 　论文类型：期刊论文

【摘要】：在理论分析水压致裂起裂机理和起裂方向的基础上,应用煤岩损伤破裂过程渗流-应力耦合分析系统,对5种不同地应力条件下的本煤层水压致裂过程进行模拟,得到了煤体的起裂方向、起裂压力和扩展压力。研究发现:侧压系数λ1时,煤体基本沿垂直方向起裂,起裂压力和扩展压力呈逐步增长的趋势;λ1时,煤体的起裂方向为水平,起裂压力和扩展压力表现出平缓降低的趋势;在λ=1时,运用3种屈服准则进行了对比分析,得到了不同判别准则下的最小起裂水压。通过对λ=1.2时的受力状态进行深入分析,提出了压裂增透范围为宏观裂隙区、微裂隙贯通区、微裂隙产生区(受拉区)和原生裂隙扰动区(压应力恢复区)之和;利用数值图像处理得到的增透面积增长趋势符合二次函数的关系。
[Abstract]:On the basis of theoretical analysis of the mechanism and direction of fracture initiation induced by hydraulic fracturing, a coupled seepage stress analysis system is applied in the process of coal and rock damage and fracture. The hydraulic fracturing process of this coal seam under five different geostress conditions is simulated, and the initiation direction, initiation pressure and spreading pressure of the coal body are obtained. It is found that the lateral pressure coefficient 位 1:00. The initiation pressure and spreading pressure of coal body are increasing gradually along the vertical direction. At 1:00, the initiation direction of coal body is horizontal, and the initiation pressure and spreading pressure show a tendency of decreasing slowly. At 位 = 1:00, three yield criteria are used to compare and analyze, and the minimum crack initiation water pressure under different criteria is obtained. The stress state of 位 ~ (1. 2) is deeply analyzed. It is proposed that the antireflection range of fracturing is the sum of macroscopic fracture area, microfracture through-through area, micro-fissure producing area (tensile zone) and primary fracture disturbance area (compressive stress recovery area). The increasing trend of antireflection area obtained by numerical image processing accords with the relation of quadratic function.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室资源及环境科学学院;重庆市能源投资集团科技有限责任公司;
【基金】：国家自然科学基金联合基金项目(U1361205);国家自然科学基金项目(51474039) 煤矿灾害动力学与控制国家重点实验室重点自主课题项目(2011DA105287-ZD201302)
【分类号】：TD712
【正文快照】： 我国国有重点煤矿48%以上为高瓦斯突出矿井。近年煤矿开采深度年平均增加15 m以上,开采煤层瓦斯压力年平均增加0.15~0.3 MPa,煤矿瓦斯灾害日趋严重。煤层瓦斯的抽采成为主要的防突措施之一,而水压致裂是一种层内卸压增透技术,能有效地增加煤层的透气率,增大瓦斯抽采量,降低煤

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