Study On Cementing Displacement Efficiency Of Old Well For Sidetrack Reaming And High Angle Well Section

At the later stage of oil and gas field exploitation,sidetracking of old wells has become one of the effective means to increase oil and gas recovery.However,the conditions of lateral drilling geology,wellbore structure and wellbore annulus are relatively complex,which has brought difficulties in ensuring the realization of "replacement net" cement injection and has affected the cementing quality.For this reason,for the specificity of sidetracking,a flushing liquid preferred experiment was carried out,and the conventional cementing displacement efficiency of the rinsing fluid and cement slurry was investigated.The cement squeezing operation process that helps to solve the problem of sealing the casing in the window opening position was proposed..The formulation of the rinsing solution was determined experimentally,the rheological parameters of the rinsing fluid and the related performance parameters of the cement slurry were obtained,the fluid flow and displacement flow model of the cementing fluid were established,and the corresponding displacement analysis physics was established based on the actual annulus structure.In the model,FLUENT software was used to numerically simulate the cement injection displacement efficiency of Heschel-Balkeley(HB)fluid,and rheological parameters,fluid density,casing eccentricity,and caliper displacement were analyzed.The law of the influence of efficiency,and the use of SPH finite element method to calculate the relationship between the pump pressure and casing thickness of the water jet perforation,put forward the water jet perforation and squeeze cement technology.The results show that the third formulation is optimal in terms of temperature resistance,corrosion resistance,settling stability,and overall performance;the relative sizes of cement slurry and drilling fluid density affect the displacement efficiency of cement slurry,and the displacement efficiency of cement slurry follows both.The difference increases and the difference increases;when the fluid medium is described by the HB model,the fluidity index increases,the displacement efficiency increases,and the consistency coefficient has little effect on the displacement efficiency;however,the dynamic shear force has little effect on the displacement efficiency;The greater the eccentricity,the narrower the gap,the greater the resistance,the more serious the retention of drilling fluid,and the lower displacement efficiency;the junction of the "bogey" well section and the normal section can easily cause the drilling fluid to stay,and it is difficult to replace the clean;The jet pressure increases,the water jet velocity and kinetic energy increase,the contact stress of the fluid impingement sleeve increases,and the damage volume of the sleeve becomes larger.The pumping pressure of 25 MPa can be selected for hydraulically assisted casing perforation cementing.