基于动态演化的深层页岩裂缝延伸规律研究

A Study of Deep Shale Fracture Extension Rule Based on Dynamic Evolution

由于埋深、应力环境、力学性质等的显著变化,深层页岩较中浅层页岩缝网形态发生了明显变化。针对深层页岩储层特点,结合利用DFN计算模型和Kaiser声发射-莫尔库伦圆室内试验,通过多因素分析,研究了深层页岩不同阶段裂缝起裂及延伸扩展的形态,并以此为基础,揭示了深层页岩裂缝系统形成过程中,各主要阶段的动态演化规律,即:主干裂缝→分支裂缝→微裂缝的变化过程。根据不同阶段裂缝特征,制定合理的压裂工艺,对于提高深层页岩改造效果具有重要指导作用。

Shale fracture web form of deep shale has changed greatly due to significant changes of its burial depth,stress environment and mechanical property.Aiming at deep shale reservoir features,combining laboratory experiment using DFN calculation model and Kaiser sound emission-Mohr Coulomb circle and based on multiple-factor analysis,this paper studies the form of deep shale fracture initiation and its extension in different stages and on this basis reveals dynamic evolution rule of all major stages in the course of deep shale fracture system formation:from the trunk fracture to the branch fracture to microfracture.Employing reasonable fracturing technology according to fracture features in different stages has an important guided role in improving deep shale modification effect.