| Injection and production is the process of injecting fluid into the underground reservoir to change the formation pressure or improve the reservoir properties to improve the oil recovery rate.Whether in the early stage of injection and production through hydraulic fracturing to create fracture channels for oil and gas migration,or the production of fractured oil and gas reservoirs,it is inevitable that they will encounter fractures.Therefore,accurately simulating the fluid pressure around the fracture can improve the accuracy of seismic exploration.The injection and production fluids used in the injection and production process and the crude oil produced are typical non-Newtonian fluids.The Darcy's penetration law derived from traditional experiments has been difficult to describe its penetration law.This paper makes full use of the mesoscopic lattice Boltzman method's multi-scale advantages to simulate the flow of non-Newtonian fluids in fractures and cause changes in surrounding pressure.Flow and pressure diffusion in cracks.Look for the diffusion law of different fluid pressures in fractures under real environment.At the same time,the lattice Blotzmann method is used to solve the partial differential diffusion equation,and the relationship between the macroscopic diffusion coefficient of the fluid and the mesoscopic relaxation factor is established.For the lattice Boltzmann equation under fracture medium conditions,polar coordinates are introduced to derive the relationship between the fracture azimuth angle and the diffusion coefficient of the fracture medium.The D2Q9 model was used to verify the effectiveness of the lattice Boltzmann method for simulating fluid pressure diffusion in anisotropic media.In the three-dimensional case,the D3Q15 model is used to verify the rationality and reliability of the method under the numerical simulation of three-dimensional fracture pressure diffusion.Prepare for the foundation of numerical simulation of pressure diffusion in actual injection-production fractures.Finally,in the simplified injection-production numerical fractures,a numerical simulation was conducted to calculate the pressure diffusion process caused by fluid migration under complex fractures in the formation.At the end of this paper,by calculating the flexibility in the cracked medium filled with pressure,the elasticity coefficient of the cracked medium is obtained from the flexibility,and then the wave equation is forward simulated.Using the equivalent elastic wave separation equation and the staggered grid finite difference method,the pure longitudinal wave field and pure shear wave wave field under injection-production fracture medium are obtained.Through the analysis and comparison of the longitudinal and transverse wave fields after separation under different injection and production conditions,the effects of different fluid pressures on the scattering attenuation of the wave field after diffusion in the fracture medium of injection and production are explored.Provide a reliable basis for the reasonable application of.ection production is a process of increasing oil production rate by injecting fluid into underground reservoir,changing formation pressure or improving reservoir properties.No matter the fracture channel of oil and gas migration through hydraulic fracturing in the early stage of injection production or the exploitation of fractured oil and gas reservoir,it is inevitable to encounter fractures.The previous research mainly focused on the macro physical parameters,such as permeability,width and density of fractures,through the test in the large-scale fracture network.However,there are few small-scale research directions,such as the migration law of fluid in fractures,the change of reservoir pressure around fractures and the propagation law of fractures.Therefore,this paper mainly studies the seepage law of fluid in the fracture and the pressure change around the fracture under the condition of injection and production. |
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