【摘要】 由于各种影响因素的存在,储层中的局部应力场会发生变化,这些变化会使储层中的应力分布不均匀。水力裂缝在延伸过程中极有可能会穿过这些应力分布不均匀的区域,而水力裂缝的扩展形态与其所处的应力状态密不可分。本文以天然裂缝周围应力场分布为例,基于有限元软件ABAQUS建立了非均匀应力场下水力裂缝扩展模型,分析了水力裂缝穿越不同应力区域时的扩展特征。研究发现:在天然裂缝附近,水平主应力的大小和方向上不同于区域构造应力;当水力裂缝扩展至最小水平主应力减小的区域时,水力裂缝的延伸速率会增加,注入点的缝宽和注入压力均会不同程度下降;当水力裂缝扩展至最小水平主应力增加的区域时,水力裂缝的延伸速率会减小,注入点的缝宽和注入压力均会不同程度增加。论文分析了非均匀应力场对水力裂缝扩展特征的影响,为现场水力压裂施工提供了理论基础。更多还原

【Abstract】 Due to the influence of various factors, the stress fields in various reservoirs will be different. In the process of extension, hydraulic fractures are likely to pass through different stress fields, and the propagation form of hydraulic fracture is related to the stress state.In this paper, considering the stress field around natural fractures, a hydraulic fracture propagation model under the non-uniform stress field is established based on the finite element software ABAQUS.The propagation characteristics of hydraulic fractures passing through different stress regions are analyzed.It shows that the magnitude and direction of the horizontal principal stress are different from the regional tectonic stress near natural fractures.When the hydraulic fracture expands to the area where the minimum horizontal principal stress is reduced,the extension rate of the hydraulic fracture will increase,and the fracture width and injection pressure of the injection point will decrease. When the hydraulic fracture expands to the area where the minimum horizontal principal stress increases, the extension rate of the hydraulic fracture will decrease, and the fracture width and injection pressure of the injection point will increase to different degrees. The paper analyzes the influence of the non-uniform stress field on the characteristics of hydraulic fracture propagation, which provides a theoretical basis for hydraulic fracturing construction site.更多还原