Isothermal Transport (Core-Flow Type) of Heavy and Ultraviscous Oil in Curved Pipes: A Transient Study by CFD

Bruno Ferreira Silva,Wanderson Magno Paiva Barbosa De Lima,Antonio Gilson Barbosa De Lima,Endyara De Morais Cabral,Ricardo Soares Gomez,Francisco Alves Batista,Adriana Barbosa Da Costa Pereira,Hortência Luma Fernandes Magalhães

doi:10.4236/ojfd.2020.102008

Abstract

In the scenery of the oil industry, the remaining resources associated with light oils have an increasingly smaller share in the natural energy resources available to man, and in return the importance of resources associated with heavy oils has increased significantly. One of the drawbacks of this type of oil is associated with its low mobility due to the high viscosity in reservoir conditions, making the transport in pipelines very difficult, especially through pumping methods that require high powers. Thus, the development of new techniques and optimization of some existing technologies, aiming at the commercial use of heavy oil accumulations plays an important role. A viable technique that has been used is the core annular flow, in which small amounts of water are injected close to the pipe wall, lubricating the oil core, reducing friction and decreasing the pressure drop during the flow. In this sense, this work aims to perform, numerically, an energetic and hydrodynamic analysis of a heavy oil-water two-phase flow, using the core-flow technique, in curved pipes, in the Ansys CFX software. Results of the velocity, pressure, and volume fraction distribution of the involved phases are presented and analyzed. It was observed that the proposed mathematical model was able to accurately represent the analyzed phenomena and that a reduction factor in the pressure drop of 28.4 was obtained as compared to the heavy oil single-phase flow.

Highlights

In the world oil production scenario, light oils, called conventional oils, have dominated the market throughout history
In the scenery of the oil industry, the remaining resources associated with light oils have an increasingly smaller share in the natural energy resources available to man, and in return the importance of resources associated with heavy oils has increased significantly
They are characterized by having a low API degree, between 10 and 20, and high viscosity ranging from 100 cP (0.1 Property Density (kg/m3) Dynamic viscosity (Pa·s)) to 10,000 cP (10 Pa·s)

Summary

Introduction

In the world oil production scenario, light oils, called conventional oils, have dominated the market throughout history. Heavy oils are composed of high molecular weight hydrocarbons, they have a high relative density, related to the presence of unwanted product contents such as asphaltenes, metallic components (nickel and vanadium) and sulfur. They are characterized by having a low API degree, between 10 and 20, and high viscosity ranging from 100 cP (0.1 Pa·s) to 10,000 cP (10 Pa·s). The production of this type of oil is, on average, twice as expensive in terms of production cost and energy consumption. This fact is related to low mobility due to its high viscosity in reservoir conditions, along with the presence of unwanted components already mentioned, making it more difficult to produce, transport and refine these oils

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