Simulação do bombeio de colchão viscoso para limpeza de cascalhos em poços de alto afastamento

Abstract

Proper oil well cleaning is crucial to avoid problems such as stuck pipe or reservoir damage. In this respect, sweeping pills are viable options because they do not offer significant risk to the well’s integrity and do not require drill pipe removal. A sweeping pill is a small volume of fluid with higher density and viscosity than the drilling fluid. Hence, it can drag cuttings away from blockage areas. Simulation and analysis is aimed at the cleaning process of an extended reach well by pumping sweeping pills. The sweeping pill’s rheology is the main focus of the investigation. The modeling of liquid-solid flow uses an Eulerian-Lagrangian approach. So, the fluid and solid phases are treated separately and coupled in four-way. For the interactions between the liquid and solid phases, a discrete phase model is implemented, while the particle interactions among adjacent particles and solid boundaries are solved by the discrete element method. The sweeping pill has a non-Newtonian pseudoplastic behavior in which the viscosity function follows the Power-Law model. The steady-state drilling mud flow with a cuttings bed was obtained in the specialized literature, and this numerical result was used as an initial field in the present simulations. At the initial time, the drilling fluid is replaced by the sweeping pill, and the fluid motion resumes. The sweeping pill is pumped until a volumetric flow of 0,06 m³/s crosses through the domain. Then, the simulation is paused and the influence of the sweeping pill’s rheology on the cleaning efficiency is analyzed. The results obtained indicate that the consistency factor is the rheological parameter with the greatest influence on the ability to carry gravel particles.