地应力差对煤层水力压裂的影响

发布时间：2018-03-16 13:35

本文选题：煤层　切入点：水力压裂　出处：《煤矿安全》2015年03期 　论文类型：期刊论文

【摘要】：为进一步揭示地应力的大小和方向对煤层水力裂缝破裂压力和裂缝几何形态及延伸的影响,从而指导水力压裂设计、施工,提高压裂抽采效果,采用RFPA数值模拟软件对不同地应力差下破裂压力和裂缝延伸的变化规律进行研究。结果表明:煤层的水力压裂过程可分为裂前、微裂和破裂3个阶段,破裂阶段初始时的注水压力即为破裂压力;破裂压力随地应力差增大而线性减小;地应力差大于4 MPa时,最大地应力方向主导裂缝延伸方向;地应力差小于2 MPa时,裂缝形态趋于复杂;地应力差越大,裂缝形态越单一,方向性越显著,主裂缝延伸范围越大,越有利于煤层的增透和瓦斯的抽采,工程应用结果与数值模拟结果一致。
[Abstract]:In order to further reveal the influence of the magnitude and direction of in-situ stress on fracture pressure and geometric shape and extension of fracture in coal seam, so as to guide the design and construction of hydraulic fracturing and improve the effect of fracturing extraction and production. The variation of fracture pressure and fracture extension under different ground stress difference was studied by using RFPA numerical simulation software. The results show that the hydraulic fracturing process of coal seam can be divided into three stages: pre-crack, micro-fracture and fracture. At the initial stage of fracture, the water injection pressure is fracture pressure, the fracture pressure decreases linearly with the increase of in-situ stress difference, when the in-situ stress difference is greater than 4 MPa, the maximum stress direction dominates the fracture extension direction, and when the in-situ stress difference is less than 2 MPa, the rupture pressure decreases linearly with the increase of in-situ stress difference. The fracture morphology tends to be complex, the larger the stress difference, the more single the fracture form, the more obvious the direction, the larger the extension range of the main fracture, the more favorable to the antireflection of coal seam and the drainage of gas. The engineering application results are consistent with the numerical simulation results.
【作者单位】：西安科技大学能源学院;
【分类号】：TD712.6

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