Isothermal and non-isothermal water and oil two-phase flow (core-flow) in curved pipes

Tony Andrade,Severino Neto,Kelen Crivelaro,Antonio Lima

doi:10.1260/1750-9548.7.3.167

Abstract

The occurrence of heavy oils in the world has increased substantially and points favorable to investment in exploration of mineral deposits and consequently, for the development of new technologies. Heavy oil has a high viscosity that varies from 100 to 10,000 times greater than the viscosity of water. The high pressure due to friction and viscous effects during the transport of heavy oil has been a major challenge, for itself to be economically viable for production or transportation. The core annular flow technique is a more recent technology favorable the explotation and transportation of heavy oils that provides a considerable reduction of pressure drop during the flow of these oils type. In this sense, this paper presents a 3D numerical study involving the heavy oil transportation in curved pipes, using the core-flow technique by CFD (ANSYS CFX® 12.0). Results of pressure, velocity, volume fraction and temperature distribution of the heavy oil are presented and analysed.

Highlights

To generate projects which provide significant volume recovery from reservoirs and improve existing projects, is of fundamental importance to develop new production technologies focused on heavy oils, especially in the scenario of offshore fields
Heavy oils present high viscosity which ranges from 100 to 10000 times greater than the viscosity of water, which makes it difficult, expensive and often unfeasible to transport these oils from the reservoir to new destination through pipelines, for example
The core-flow technique does not alter the oil viscosity, but transforms the flow pattern and reduces friction during transport of very viscous products, such as heavy oils. This flow pattern is characterized by a water pellicle that is formed close or adjacent to the inner wall of the pipe, functioning as a lubricant

Summary

Introduction

To generate projects which provide significant volume recovery from reservoirs and improve existing projects, is of fundamental importance to develop new production technologies focused on heavy oils, especially in the scenario of offshore fields. The core-flow technique basically consists of injecting small quantities of water at a flow rate lower than the oil causing the heavy oil to be surrounded by a layer of water and flowing in the center of the pipe without touching the inner wall of the pipe, thereby establishing an annular pattern. The core-flow technique does not alter the oil viscosity, but transforms the flow pattern and reduces friction during transport of very viscous products, such as heavy oils. This flow pattern is characterized by a water pellicle that is formed close or adjacent to the inner wall of the pipe, functioning as a lubricant. The oil flows in the center of the pipe causing a reduction in longitudinal pressure drop [8]

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