诱导应力下天然裂缝的稳定性及破坏特征

发布时间：2018-03-02 01:03

本文关键词： 天然裂缝逼近过程诱导应力稳定性破坏特征　出处：《大庆石油地质与开发》2017年06期 　论文类型：期刊论文

【摘要】：为了探讨水力裂缝激活天然裂缝的力学机制,基于线弹性断裂力学理论,建立了水力裂缝扩展过程中天然裂缝面诱导应力场解析模型,分析了水力裂缝逼近条件下天然裂缝的稳定性行为及破坏特征。研究表明:天然裂缝的稳定性受到水平应力差、水平应力差异系数、孔隙压力、压裂液黏度及排量、逼近距离、天然裂缝空间展布及粗糙度等因素影响;逼近过程中天然裂缝可能同时出现张性和剪切滑移破坏,但更易发生剪切破坏,且剪切破坏区明显大于张性破坏区,破坏区也主要出现在倾斜天然裂缝的正半轴上,负半轴几乎没被激活;天然裂缝的失稳中心随着走向角的减小逐渐向正半轴移动,随着逼近距离减小逐渐向负半轴移动,其他因素对失稳中心影响很小。研究成果对体积改造复杂缝网形成机制的研究具有重要的参考价值。
[Abstract]:In order to investigate the mechanical mechanism of natural fracture activation by hydraulic crack, an analytical model of induced stress field of natural fracture surface during the process of hydraulic crack propagation is established based on the theory of linear elastic fracture mechanics. The stability behavior and failure characteristics of natural fractures under the condition of hydraulic fracture approximation are analyzed. The results show that the stability of natural fractures is affected by horizontal stress difference, horizontal stress difference coefficient, pore pressure, fracturing fluid viscosity and displacement, approaching distance. In the process of approaching natural cracks, tensile failure and shear slip failure may occur at the same time, but shear failure is more likely to occur, and the shear failure zone is obviously larger than the tensile failure zone. The failure zone also mainly appears on the positive half axis of inclined natural fracture, and the negative half axis is almost not activated, the instability center of the natural crack moves gradually to the positive half axis with the decrease of strike angle, and gradually to the negative half axis with the decrease of approaching distance. Other factors have little influence on the center of instability. The research results have important reference value for the study of the formation mechanism of complex seams in volume transformation.
【作者单位】：中国石油大学石油工程学院;
【基金】：国家自然科学基金“液氮辅助页岩体积压裂增效机理研究”(51574270) 教育部长江学者和创新团队发展计划项目(RT1086)
【分类号】：TE357.1

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