Study On Fracture Shape And Flowback Characteristics Of Mahu Tight Reservoir

In view of the characteristics that there are a large number of structural weak surfaces in the tight conglomerate reservoir,which leads to the formation of complex fracture network during the fracturing process,starting from the hydraulic fracturing simulation,the boundary element numerical simulation method is used to simulate the hydraulic fracturing of Mahu tight reservoir.The effects of cluster spacing,number of clusters in a single section,sand addition strength and other construction parameters on the length,width and morphology of fractures are studied,And the influence of reservoir gravel density on the development of hydraulic fractures.Based on the complex fracture network simulated by hydraulic fracturing,the fracturing fluid filtration and flowback are simulated,the reasonable water injection process is set to simulate the fracturing fluid filtration into the formation,and the production performance is calculated in combination with the on-site flowback and production system.The influence of fracture network complexity on fracturing fluid flowback characteristics is analyzed from the perspective of space and time.Around the fracture surface is the main area of fracturing fluid filtration.The content of fracturing fluid in the formation above and below the fracture is low,and the amount of fracturing fluid in the fracture is small.The fracturing fluid in the fracture decreases rapidly during well stewing;The high-flowback in the early stage of flowback is mainly provided by the rapid flowback of fracturing fluid in the high-permeability fracture,and the lowflowback in the later stage is mainly provided by the low-permeability of water invasion area.Based on the understanding of numerical simulation,the early and late mathematical models of fracturing fluid flowback are established,and the hydraulic fracture volume is successfully calculated by using the early flowback model.The influence of different fracture patterns on fracturing fluid flowback curve is analyzed,and the typical characteristics of fracturing fluid flowback curve are summarized.