Transporte de óleos pesados e ultraviscosos via core-flow: aspectos geométricos e termofluidodinâmicos.

Abstract

The occurrence of heavy and extra-heavy oil in the world has increased significantly, which leads to the need for greater investment in the reservoirs exploitation and development of new technologies for the transportation of these oils. In this sense, this work presents a numerical study involving the transport of water and heavy oils in horizontal pipes, curved pipes and T connections (with sharp edges or smoothed) employing the core annular flow technique by ANSYS CFX® Release 12.0 commercial software. It was used a multiphase mixture model to treat the threedimensional, transient, isothermal and non-isothermal, oil-water two-phase flow, assuming laminar flow to oil phase and turbulent flow to water phase (turbulence model k. Results of the pressure, velocity, temperature and volume fraction ditribuition of the phases and the pressure drop over time are presented and evaluated. It was verified that the presence of a water film near the pipe wall surrounding the core of heavy oil flowing in the central region of the pipe (core annular flow) have performed a high reduction in pressure drop ranging from 90% to T conection with live corners up to 96% for the curved pipe during the two-phase flow when compared with the single phase flow of heavy oil for the same operating conditions. It was observed that the oil core flows eccentrically in the pipe and stops in the flow of water considerably increases the pressure drop in the pipe, so after the restart of the pump the system pressure decreases rapidly.