【作者】 朱海燕； 汪浩威； 郭建春； 李慧；

【Author】 Zhu Haiyan;Wang Haowei;Guo Jianchun;Li Hui;Southwest Petroleum University;

【机构】 西南石油大学；

【摘要】 为了研究通道压裂后裂缝的分布形态以及导流能力,本文建立了通道压裂缝宽计算模型,研究支撑柱分布位置、支撑柱性质和地层参数(弹性模量、闭合压力等)对缝宽和导流能力的影响规律,并进行适用性评价。本文从支撑柱的变形和嵌入两方面描述缝宽变化。基于岩土力学理论,假设支撑柱为非线性弹性体,通过参数反演可得到其本构关系;利用经典弹性理论来描述支撑柱与岩石的接触变形关系,定量分析闭合压力下支撑柱在岩石中的嵌入量。考虑支撑柱变形、嵌入以及应力干扰,通过叠加原理,得到缝宽计算模型,实现了任意支撑柱分布下的缝宽预测。得出以下结论:(1)支撑柱变形呈先快后慢的趋势,且存在明显的压实过程;(2)距离支撑柱受力面越近,形成的高速通道越宽;(3)当支撑柱性质和地层参数一定时,存在最优支撑柱间隔,使裂缝导流能力最高;(4)为了准确评价通道压裂适用性,应该结合地质特征和支撑柱性质综合分析。更多还原

【Abstract】 In order to study fracture form and flow conductivity after channel fracturing, this paper established a new model to predict fracture width in channel fracturing to study the effect rule of distribution of proppant pillars and formation parameters(elastic modulus, closure stress, etc.) on fracture width and conductivity, and made a applicability evaluation. This paper describes fracture change from deformation and embedment of proppant pillars. Based on theory of rock-soil mechanics, proppant pillar is assumed as nonlinear elastomer, and its constitutive relation can be obtained by parameter inversion. The contact relationship between proppant pillar and rock was described by classical elastic mechanics theory, and the embedded depth of the proppant pillar was quantitatively analyzed. Considering deformation and embedment of paoppant pillar and stress interference, the model to predict fracture width was obtained by superposition principle, and the fracture width under any distribution of pillars could be obtained. The following conclusions could be obtained:(1)the deformation of proppant pillar appears first quick back slow trend, and there is an obvious compaction process;(2)the closer the proppant pillar, the wider the fracture;(3)when other parameters are certain, there is an optimal spacing between proppant pillars to make the flow conductivity highest;(4)it is better to evaluate the applicability of channel fracturing by combination of characteristics of proppant pillar and rock.更多还原