水力裂缝平面应变假设的适用条件与解析修正

发布时间：2018-04-06 23:09

  本文选题：水力压裂　切入点：平面应变　出处：《石油勘探与开发》2017年03期

【摘要】：鉴于平面应变假设在模拟水力裂缝周围应力、位移分布的模型中得到了广泛应用,通过对比椭圆裂缝解和平面应变解,探讨了平面应变假设的适用条件并给出了修正方法。在前人研究的基础上推导、补充并修正了扁平椭圆裂缝的应力、位移场表达式,与平面应变假设条件下的计算结果进行了比较,结果表明:若在缝高方向考虑平面应变假设,长高比大于10后,平面应变解与椭圆裂缝解之间的差异可以忽略,而在主要受缝面法向正应力控制的问题中,平面应变解的适用条件可以放宽到长高比大于5;当长高比满足适用条件时应用平面应变假设具有较高精度,长高比较小时需要对平面应变解进行修正。给出了不同长高比条件下裸眼水平井起裂附加应力和单条裂缝宽度的平面应变解修正图版,发现拟三维模型的缝宽更易于修正。
[Abstract]:Since the plane strain hypothesis has been widely used in the model of simulating the stress and displacement distribution around the hydraulic fracture, by comparing the elliptical crack solution with the plane strain solution, the applicable conditions of the plane strain hypothesis are discussed and the correction method is given.On the basis of previous studies, the stress and displacement field expressions of flat elliptical cracks are deduced and modified. The results are compared with those calculated under the assumption of plane strain. The results show that: if the plane strain hypothesis is considered in the direction of joint height,When the ratio of length to height is greater than 10, the difference between the plane strain solution and the elliptical crack solution can be neglected.The suitable conditions of plane strain solution can be relaxed to the ratio of length to height greater than 5, and when the ratio of length to height satisfies the applicable condition, the assumption of plane strain has a higher accuracy, and when the ratio of length to height is small, the plane strain solution needs to be corrected.In this paper, the correction chart of plane strain solution for open hole horizontal well with different ratio of length to height is given. It is found that the crack width of pseudo-3D model is easier to be corrected.
【作者单位】： 油气藏地质及开发工程国家重点实验室(西南石油大学);中石化河南石油工程有限公司;
【基金】：国家自然科学基金重大项目(51490653) 国家重点基础研究发展计划(973)项目(2013CB228004)
【分类号】：TE357.1
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本文编号：1719316