NUMERICAL STUDY OF OIL WELL PLUGGING PROCESS

Rafael José Cavalieri Feital¹; Monica Naccache¹

¹ Pontifical Catholic University of Rio de Janeiro

doi:10.20906/CPS/COB-2015-0348

Resumo

The plugging process of an oil well is analyzed numerically. The problem consists on two fluids with different densities placed one above other: the cement plug and the drilling fluid. The higher density fluid is the cement plug, modeled as non-Newtonian, and placed above the drilling fluid, which is considered Newtonian. This unstable situation is studied using the ANSYS Fluent software. The conservation equations are solved using the Finite Volume Method, and the multiphase flow is modeled with the Volume of Fluid method. The non-Newtonian viscoplastic behavior of the cement plug is modeled with the Generalized Newtonian Fluid constitutive equation, with the Herschel-Bulkley viscosity function. The success of the operation is determined by the combination of the governing rheological and geometric parameters. The effect of the governing parameters, such as the density ratio and the viscosity ratio, are investigated for a fixed geometry and a fixed ratio between the cement plug length and diameter. Furthermore, the influence of this ratio in the process is also analyzed while others governing parameters are fixed. It is shown that the flow is highly unstable, and that the governing parameters considerably affect the operation.

Palavras-chave: viscoplastic; non-newtonian; rheology; stability; oil well plugging