Coiled tubing cementing has grown as an attractive option for plugging and abandonment (P&A) operations in deepwater environments. Flow through long extension coils generates extra friction which results in relevant pressure and temperature increments in the cement slurry pumping process. Petroleum industries do not have standard procedures to predict these variables that impact slurry properties in deepwater cementing. This fact leads to conservative slurry designs, generating extra costs and eventually affecting its stability.
This work describes the proposition of a mathematical model to predict friction and heat transfer while pumping cement slurries and all the associated fluids through a coiled section. Based on momentum and energy conservation laws, the proposed model aims to generate representative transient pressure and temperature profiles to be coupled to the wellbore thermal model and, finally, provide a reliable schedule for thickening time testing. A broad discussion on initial and boundary conditions allows accounting for fluid-metal-environment heat exchanges. A comparison with different field measurement sets obtained from deepwater cementing operations indicates relative deviations smaller than 10%. The implementation of the methodology leads to the design of optimized slurries, reducing operational costs due to additives and WOC times and risks associated with sedimentation.