Research On Multistage Temporary Plugging Acidification Simulation In Horizontal Wells

The main purpose of the acidizing of horizontal wells in carbonate reservoirs is to remove the damage of near-wellbore reservoirs or form new flow channels,increase the connectivity between the wellbore and the reservoir,restore and increase the productivity of horizontal wells.And conventional acidizing technology is difficult to achieve uniform placement of acidizing fluid.Temporarily block acidizing technology can effectively solve the problem of acidizing and deblocking in non-uniform reservoirs and formations with different clogging levels and improve the acid absorption profile of the formation.It is a simple,effective,and easy acidizing technology.In this paper,through a large number of literature investigations,on the basis of research on the horizontal well pollution belt,considering comprehensive consideration of fluid flow in horizontal wells,acid and rock reactions,and temporarily block of fiber dissolution,a multi-stage transient plug acidizing simulation model for horizontal wells was established.The following work was mainly completed:(1)Based on the pollution characteristics of drilling fluid in horizontal wells,the fluid loss in the formation is simulated and the depth of drilling fluid pollution at different well locations is obtained.Considering factors such as pollution radius,pollution degree,reservoir properties,and permeability anisotropy index,a comprehensive skin factor calculation model was established.(2)A numerical model of the near-wellbore formation temperature field was established by considering the heat of the acid rock chemistry reaction.The near-wellbore formation temperature during the acid injection was simulated.The distribution of the temperature field near the wellbore during the acidizing operation was analyzed,and parametric sensitivity analysis was performed.(3)Considering the fluid loss and frictional resistance of the acid in the advancement of horizontal wells,the calculation model of the hydraulic friction resistance,the dynamic response model of the acid fluid and the reservoir,and the fluid loss calculation model along the wellbore are integrated.An acid propulsion model in a horizontal wellbore was established and calculated.(4)A model of heterogeneous reservoir acid absorption profile that comprehensively considers the fluid flow in the well section of the horizontal well,the formation acid-rock reaction,and the temporarily block acidizing was established to simulate the temporarily block acidizing process and analyze the influence of different parameters on the uniform acid production effect.And optimize the temporarily block acidizing process parameters.The research results of this paper have certain guiding significance for the development of multilevel temporarily block acidizing model for horizontal wells in carbonate reservoirs and the optimization design of temporarily block acidizing process parameters.