Fluid-solid Coupling Research Of Layered Injection And Production Based On ABAQUS

The use of artificial water injection to maintain formation pressure to develop an oil field is a major turning point in the history of oil field development.In order to maintain stable production and high recovery efficiency,the water injection method is transformed from general water injection to layered water injection and fine layered water injection.During the water injection process,the physical parameters in the reservoir are always in a state of dynamic change.The reason is that the injection and production of formation fluid changes the pore pressure of the formation.According to the principle of effective stress,if the total stress remains unchanged,the effective stress will be redistributed.When the reservoir rock expands or compresses,the porosity and permeability also change.This phenomenon is the fluid-solid coupling effect.In the process of stratified injection and production,the dynamically changing pore pressure,porosity,permeability and rock deformation under the action of fluid-solid coupling directly affect the pressure front and oil-water front of each development strata,so it is related to the oil and gas production volume.Closely related.In order to adjust the stratified injection-production work system in time to ensure the maximum oil production of each development strata,it is necessary to predict the change law of reservoir parameters and reveal the distribution law of reservoir seepage field and stress field.Therefore,the dynamic coupling between the changes in the seepage state of the reservoir pore fluid,the change in the stress state of the rock skeleton and the deformation of the reservoir rock caused by water injection and extraction must be considered.The research on fluid-solid coupling in stratified injection and production has mainly completed the following aspects:First,a stratified water injection model is established,and the effective injection pressure is obtained under the condition of the pressure loss along the pipe string and the pressure loss of the adjustable nozzle.Calculate the water injection volume of each development strata in the injection-production unit and the indicator curve of the water injection well;secondly,the fluid-solid coupling mechanism and process are studied,and the dynamic evolution model of the physical parameters of the sandstone reservoir during the layered injection-production process is derived and established;Finally,use the ABAQUS software to perform numerical simulations on single-layer water injection development and double-layer general water injection development,and obtain the dynamic changes of pore pressure,rock volume strain,porosity and permeability during the injection-production development process.The amount of water injection controls the position of the pore pressure front in the process of layered injection and production,and improves the mining effect.The research results show that due to the different physical property parameters set for the upper and lower reservoirs of the model,the pore pressure,rock volume strain,porosity and permeability of the upper and lower reservoirs have the same changing trend during the general water injection development process,but the change range is different.The range of pore pressure changes in the upper and lower reservoirs is about 6%and 16%respectively;the absolute value of rock volume strain is about 0.00085;the range of porosity changes is about 3%;the range of permeability changes is about 1%.In the process of stratified injection and production,by adjusting the water injection volume of the upper and lower reservoirs,the changes in the physical parameters of the upper and lower reservoirs are basically synchronized,and the pressure front and the oil-water front are basically the same.The range of pore pressure changes in the upper and lower reservoirs is about 16%;the absolute value of rock volume strain is about 0.0008;the range of porosity changes is about 5%;the range of permeability changes is about 2%.The simulation results have achieved the expected results,which have certain reference value for the long-term planning of the stratified water injection development of oil and gas fields and the adjustment of production plans to achieve stable and high production,and will contribute to the national economy and resources.