Study On The Mechanism Of Pulsating Cyclic Water Injection

At present,most oil fields in China have entered the stage of medium and high water cut.Based on the principle of seepage flow mechanics,the oil Wells can be adjusted by means of the implementation of water cycle water injection,dynamic way,the periodic change of injection and recovery process,make full use of the reservoir in the capillary force and the elastic energy exchange between high and low permeability zone caused by seepage,and stress field of the periodic changes of conventional water injection conditions were stranded in the remaining oil flow,make the oil in the low permeable interval and unswept areas is produced,so as to achieve the aim of improve the recovery efficiency,improve the development effect.Based on the cyclic waterflooding in indoor experiment and theoretical study and field test research,try to shorten the cycle time is put forward,the author puts forward the concept of pulsating cycle water injection,on the basis of cyclic waterflooding,comprehensive analysis from the aspects of the theory of the pulse water injection oil displacement mechanism of vertical from reservoir heterogeneity and plane heterogeneity explain both capillary force,elastic force in the process of the pulsating cycle water injection to improve oilfield development effect of macro mechanism and micro mechanism.The mechanism of improving the development effect of water drive in vertical heterogeneous reservoirs is mainly caused by interlayer interflow caused by capillary force and elastic force.In this way,the dead oil zone can be reactivated.The influence of additional pressure on vertical heterogeneous reservoir is the main reason of pulsating water injection.The mathematical model of additional pressure is established theoretically.And according to the oil and water two phase percolation theory and darcy’s law,on this basis,from the direction of the horizontal displacement and vertical permeability direction respectively set up considering two absorption flow channel seepage mathematical model of water saturation changes,eventually establish the coupling model of two channels,the injected water in the process of water drive the change of formation water saturation,and the mathematical model is solved by finite difference method,the qualitative analysis of capillary force,gravity and additional stress in the process of pulse water injection effect.Through reservoir numerical simulation method to analyze the influence factors of pulse water injection,capillary force,reservoir heterogeneity,elastic force,viscosity of crude oil and formation anisotropy of pulsating cyclic waterflooding effect,for the future further research and implementation of pulsating cyclic waterflooding field test provides the reference basis of theory and technology.