Hydraulic fracture is widely performed to enhance oil and gas production in the development of unconventional reservoirs. This paper proposes a numerical model for the calculation of the unpropped fracture conductivity of shale. This numerical model consists of three basic models, namely, the numerical reconstruction model of fracture morphology, fracture deformation model under closed stress, and fluid flow model. The numerical model can be used to analyze the influencing factors of the unpropped fracture conductivity of shale quantitatively. The results demonstrate that the fracture misalignment of shale is a prerequisite for unpropped fractures with conductivity at high closed stress. Furthermore, the unpropped fracture conductivity of shale decreases exponentially with the increase in closed stress. Moreover, closed stress is the factor having the most significant influence on the unpropped fracture conductivity of shale, followed by roughness and fracture morphology. The negative effect of closed stress can be reduced by increasing the fracture morphology during the fracturing operation.

中文翻译：

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页岩无支撑裂缝电导率的影响因素

在非常规油藏开发中，广泛进行了水力压裂，以提高油气产量。本文提出了一个数值模型，用于计算页岩无支撑裂缝的电导率。该数值模型由三个基本模型组成，分别是断裂形态的数值重建模型，闭合应力下的断裂变形模型和流体流动模型。该数值模型可用于定量分析页岩未支撑裂缝导流能力的影响因素。结果表明，页岩裂缝错位是高封闭应力下电导率无支撑裂缝的先决条件。此外，随着闭合应力的增加，页岩的无支撑裂缝导流率呈指数下降。此外，闭合应力是对页岩未支撑裂缝导流能力影响最大的因素，其次是粗糙度和裂缝形态。闭合应力的负面影响可以通过增加压裂操作中的断裂形态来减少。