基于管单元的水平井多簇压裂有限元模拟方法

A finite element simulation method for multi-fracture propagation in horizontal wells based on fluid pipe element

为了研究水平井多簇压裂工艺中的复杂过程,如射孔限流、炮眼冲蚀以及动态封堵现象,基于ABAQUS有限元计算平台并考虑这些复杂过程开发管单元,构建一种水平井多簇压裂的有限元模拟方法,与有限元框架模型耦合完成不同场景下水平井多簇压裂模拟。结果表明基于管单元的水平井多簇压裂有限元模拟数值结果与目前应用广泛的全耦合裂缝扩展模型结果基本一致,证明此模型的准确性;暂堵后原本不进液的中间裂缝可有效进液,原本优势进液的裂缝得到抑制,投球暂堵可促进各簇裂缝的均衡进液;射孔冲蚀会增加射孔直径与流量系数,进而降低多缝限流效果;三簇裂缝受冲蚀影响程度由大到小顺序为根部边缝、趾部边缝、中部裂缝。

In order to study the complex processes during multi-cluster fracturing in horizontal wells,a fluid pipe element was figured out based on the ABAQUS finite element analysis platform,in which various factors influencing the fracturing process can be considered,including the limited entry in perforation,the erosion of perforation holes and the dynamic plugging in fractures.In comparison with the conventional fully coupled model,the accuracy of the newly developed finite element model based on the fluid pipe element was verified.The simulation results indicate that temporary plugging in the fracturing process can promote simultaneous propagation of multiple fractures,which can increase the flow rate in the fractures at the middle section and suppress the flow in the main fractures near the wellbore.The erosion of perforation holes can increase the flow coefficient of the perforations,which in turn can decrease the limited-entry ability of the perforations.The order of the three fractures affected by the perforation erosion is heel fracture,toe fracture,and middle fracture.