Numerical Simulation Of Acid Fracturing In Fractured Carbonate Reservoirs

Carbonate rock reservoir rock density,poor hole seepage properties,reservoir hole throat coordination is low,connectivity is poor,non-homogeneous strong,acid pressure is currently one of the most widely used carbonic rock reservoir production measures,decided acid pressure transformation effect evaluation index is mainly live acid action distance and acid pressure crack diversion capacity.Facing the carbonate rock reservoir developing more natural cracks,due to the existence of natural cracks,the reservoir permeability is higher,which will aggravate the filtration loss of acid in acid pressure process,thus affecting the flow ability of the active acid action distance and acid erosion cracks,the existing carbonate acid pressure model fails to take into account the effect of the non-uniform distribution of penetration between natural cracks and cracks on the surface of the filter,so the acid pressure prediction model simulates the effect of active acid distance and acid pressure crack conductivity.It is not possible to accurately simulate the acid pressure crack conductivity of the crack-type carbonate rock reservoir.In view of this problem,a new acid pressure model of crack-type carbonate rock reservoir is established by theoretical research and numerical simulation.First,based on the geological statistical law,GSLIB software is used to establish the non-uniform permeability distribution on artificial crack surface,and then the random natural crack parameters are generated by Monte Carlo random simulation method,the natural crack distribution is generated according to the geological statistics law,and then the acid flow model,acid filter loss model,acid rock reaction mathematical model and rough acid corrosion crack surface formation simulation model are established respectively.Then a wide range of numerical simulations were carried out based on the model,and the simulation results when considering the existence of natural cracks were compared with the effects of acid type,acid viscosity,pump injection displacement and natural crack parameters on the distance of active acid and the ability of acid corrosion cracks to conduct the flow.After the use of the software for Shanxi Linxing block acid pressure transformation block for the scheme design,based on the simulation results for acid pressure parameter optimization,acid erosion crack conductivity prediction,so as to achieve the target well acid pressure scheme to provide technical guidance.As the current carbonate rock reservoir acid pressure model does not take into account the impact of natural cracks and non-uniform permeability distribution,this paper aims to know the acid pressure modification design of the fissure-type carbonate rock reservoir through the new model established in this study,and also provides some reference for the development of similar carbonate rock reservoirs.