压裂过程射孔孔眼冲蚀动态演化过程数值模拟

Dynamic Evolution of Perforation Erosion During Sand Fracturing Based on CFD-DEM Simulation

在套管加砂压裂阶段,由于支撑剂对射孔孔眼的冲蚀,导致孔眼摩阻骤降,同时伴随着严重的扩径与变形。为此,基于Rocky DEM方法探究孔眼的冲蚀动态演化过程和孔眼摩阻衰减规律。结果表明,孔眼的冲蚀变形包括孔肩冲蚀和扩径冲蚀两个阶段。在排量20 m^(3)/min、砂含量150 kg/m^(3)、100目石英砂的模拟条件下,孔眼摩阻的衰减主要发生在孔肩冲蚀阶段。在0~500 s之间,孔眼摩阻由冲蚀前的15.88 MPa降低至4.41 MPa。

During the sand fracturing stage,severe diameter expansion and deformation was occurred as the erosion of the perforations by the proppant,in result of reducing the friction of the perforations.In this work,the Rocky DEM method was used to investigate the dynamic evolution process of perforation erosion and the attenuation law of perforation friction.The results show that the erosion deformation of the perforation includes two stages:perforation shoulder erosion and diameter expansion erosion.Under the simulation conditions of displacement 20 m^(3)/min,sand content 150 kg/m^(3),and 100 mesh quartz sand,the attenuation of perforation friction mainly occurs in the perforation shoulder erosion stage.Between 0~500 s,the perforation friction decreased from 15.88MPa before erosion to 4.41 MPa.