Research On Reservoir Damage Caused By Well Injection And Production Parameters Of Pumping Unit In Hyperpermeability Sandstone Reservoir

Oilfield water injection development can add energy to the reservoir and improve oilfield recovery.It is currently the most widely used development method at home and abroad.During the development of water injection,the complex interaction of rocks,fluids and external fluids in the reservoir causes changes in the environment of the reservoir,resulting in varying degrees of reservoir damage.High-permeability sandstone reservoirs have porosity,high permeability,and rock strength The characteristics of low,often instability of the well wall,sand production and large pores in the water injection development,so it is very important to study the damage problems of reservoir water injection development.In this paper,the damage in the process of water injection is studied from three perspectives: the cause of reservoir damage,the interaction process of reservoir fluid and rock,and the impact of changes in injection flow rate on reservoir physical properties.The specific research contents and conclusions are as follows:The composition and structural characteristics of sandstone reservoirs are studied,including the pore characteristics and cementation characteristics of sandstone rocks;loose sandstone rocks are mainly intergranular gaps and contact cementation.They are weakly cemented sandstones,and the composed rocks have low macro strength.On this basis,the internal and external causes of sandstone reservoir damage are explained;the internal factors are potential factors of reservoir damage,including clay mineral damage,reservoir sensitivity,rock surface properties,etc.The external factors are causing reservoir damage Conditions,including damage during drilling,perforation,fracturing,acidification,etc.Taking the montmorillonite structure as an example,the process of hydration and expansion of clay minerals is analyzed,and the damage of reservoir particle migration and water injection quality to the reservoir is explained;the change of particles in the fluid and the ion reaction are the beginning of reservoir damage,And explains common reservoir damage phenomena.The stress-strain model of the reservoir rock and the elastic elastoplastic constitutive relationship of the rock are studied.The coupling process of the reservoir rock and fluid is discussed.Based on this,the volume strain caused by the change of the rock's skeleton stress is taken into consideration Dynamic evolution model of permeability and porosity in the process of layer coupling.Using the established porosity and permeability models,the ABAQUS software was used to establish the injection-production model of the reservoir anti-square five-point well pattern,and the numerical simulations were used to investigate the damage of reservoir injection flow rate,density and production well flow rate to the reservoir physical properties.The results show that : Increasing the injection flow rate and density will increase the reservoir pore pressure,average permeability and porosity,but has little effect on the pore pressure and permeability of the production well,while the increased production flow rate will reduce the pore pressure and permeability of the production well The rate and porosity are reduced.