Study On The Rule Of Proppant Displacement In Fractures Of Slickwater Fracturing

Slickwater fracturing is an important stimulation technique for unconventional oil and gas resources exploration and development,and plays an important role in the exploitation of unconventional reservoirs such as shale gas and tight sandstone gas.The key of hydraulic fracturing is to form sand packed fractures which meet fracture conductivity.The distribution ofproppant in the fractures directly determines the effect of stimulation.At present,the research about the proppant placementin fractures is mainly based on Babcock’s model under small pumping rate,but theproppant placement under large pumping rate is not clear,especially in the effect of turbulence at the entrance of fractures,which is still need further study.In this paper,the main influencing factors of proppant placement are theoretically analyzed by theoretical calculation program.Using large-scale visualization of parallel fracture simulation device to study the proppant placement under large pumping rate and analyzing the impact of influencing factors on the distribution of proppant,the equilibrium height,the equilibrium time,the leading edge distance and the leading edge height.At the same time,based on the physical experiment,the geometric numerical model was established by using Gambit preprocessing software.Fluent software was used to simulate the proppant placementin fractures and further analyzed the influence of the turbulence effect.Through the above research,this paper has achieved the following three points:(1)The proppant placement in the fractures under large pumping rate isdifferent from that in traditional small pumping rate,and it is more obvious in the effect of turbulence at the entrance of fractures.(2)In order to describe the effect of turbulence under large pumping rate on the proppant placement,the height of the front edge of proppant is introduced,so as to describe the proppant placement in the fractures more comprehensively.(3)By comparing the results of physical experiments and numerical simulation,the correctness and feasibility of the numerical simulation of proppant placement are verified,and using numerical simulation method analyze the effect of turbulence and the viscosity of fracturing fluidunder large pumping rate on the proppant placement,which will provide some reference for the design of fracturing construction scheme.