Finite Element Modeling of Heavy Oil Production Using PCP

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe Progressive Cavity Pumping (PCP) system has become one of the most attractive artificial lift methods used for heavy oil production in land fields. One of the problems associated with PCP is the prediction of the pressure losses in the annular flow between the production tubing and the rod string, which transmits power downhole to the PCP. The irregular annular section due to the rod upsets and the non-Newtonian behavior of some heavy oil initially precludes any analytical approach of the problem, requiring the use of numerical solution. Different heavy oils from onshore and offshore Brazilian fields were rheologically characterized using a straincontrolled rheometer in order to study temperature and elasticity effects on its rheological behavior.For the temperature and strain rate ranges used in the lab, the Power Law model has been chosen to represent the fluid behavior for the numerical simulation of the annular flow field. In order to understand the physical problem, a 2D finite element modeling of the laminar, steady-state, helical flow of a generalized Newtonian fluid was performed, by using Newton's method with an incremental loading scheme. A mixed formulation was applied for the approximation of Navier-Stokes equations and the flow domain was discretized by quadratic quads with linear pressure interpolation. The general conclusions regarding the physical problem are concerned with the rheological behavior of the fluid and with the parameters which mostly influence the pressure losses in the annular flow, during progressive cavity pumping of the heavy oil.