Simulation Study On Temporary Plugging And Acidification Of Horizontal Wells In Carbonate Reservoirs

Matrix acidizing is a very important treatment to remove damage and to restore or improve production.And conventional acidizing technology is difficult to achieve uniform placement of acidizing fluid.Because of efficient temporary plugging ability,adaptability and low damage,temporary plugging acidification technology has been widely used in uniform placement.However,there are some key issues need to addressed in horizontal well when temporary plugging and acidification of carbonate reservoirs,like unfamiliar with cross-sectional,lack of complete simulation model,select key parameter arbitrarily in actual construction.Therefore,based on horizontal well of non-uniform pollution,the temporary plugging acidification model of horizontal well is established,considering the acid flow reaction,soluble temporary plugging agent,various fluid alternating injection.Main research works in this paper are as follows:(1)Considering the construction parameters of drilling and the non-uniform distribution of reservoir properties along the horizontal section,the non-uniform damage model of horizontal wells is established which can simulate the injury to heterogeneity of reservoir,get the shape and radius of pollution,skin factor with the distribution along the horizontal section.(2)Considering the reaction of carbonate rocks with acid and the reservoir unstable flow,the flow-reaction model of acid is built.Combining this model with non-uniform damage model,it can stimulate the influence of reservoir parameters and engineering parameters to the acid distribution.(3)Through the evaluation of fiber temporary plugging agent performance and temporary effects,the concentration of 1%-2%of 6mm fiber is recommended as temporary blocking agent to temporary blocking acidification.(4)Temporary plugging acidification model is built to simulate the acid placement in the temporary plugging process,considering the dynamic advancing in the wellbore,dissolving of temporary plugging agent,a variety of working fluid alternately injection,which stimulates the acid absorption profile of formation.And combining with the temporary plugging acidizing wells to stimulate and design the pump injection procedure.Theoretical analysis and field application show that temporary plugging acidification can effectively improve the acid absorption cross section to achieve uniform placement.The research results in this paper have a great significance in promoting the temporary plugging acidification technology development in carbonate reservoir horizontal well.