Numerical simulation of heavy oil flows in pipes using the core-annular flow technique

Abstract

The importance of heavy oils in the world market for petroleum has increased very quickly in the last years. The reserves of heavy oils in the world are estimated at 3 trillion barrels, while reserves of light oils have reduced progressively in the last decade. The high oil viscosity creates major problems in the production and transportation of the oil. This situation leads to the high pressure and power required for its flow, overloading and damaging the equipment, increasing the cost of production. Due to the need to develop new alternatives that will make the production and transport of heavy oil economically viable, this work has the objective to study, numerically, the behavior of isothermal multiphase flow (heavy oil and water), type "core flow", in pipelines, using the software CFX ® 3D. The pressure drop was determinated to a core-flow in a pipe with 7 in. diameter, 2.7 Pa.s oil viscosity and water at environment temperature. Results of the pressure, velocity and volume fraction distributions of the phases are presented and analyzed. It was verified that the pressure drop was reduced 58 times when compared to that obtained with oil flow alone in the pipe.

Modeling Friction Losses in the Water-Assisted Pipeline Transportation of Heavy Oil

“…Lubricated pipe flow has been applied in a specific industrial context for transporting viscous oils like heavy oil and bitumen with limited success in many cases [1,3,9,18,20,21]. A challenge to the broader application of LPF technology is the lack of a reliable model to predict frictional pressure losses, even though numerous empirical (e.g., [12,13]), semi-mechanistic or phenomenological (e.g., [10,11,15]) and idealized models (e.g., [14,32,33,[35][36][37]) have been proposed to date. The existing models were developed based on either single-fluid or two-fluid approach.…”

“…The benefit of LPF is that it is a specific flow regime in which a continuous layer of water can be found near the pipe wall. As wall shear stresses are balanced by pressure losses in any kind of pipeline transportation, this flow system requires significantly less pumping energy than would be required to transport the viscous oil alone at comparable process conditions [10,[11][12][13][14][15][16][17].…”

Applying CFD in the Analysis of Heavy-Oil Transportation in Curved Pipes Using Core-Flow Technique

“…However, the influence of the gas phase in the core-flow on pipelines and connections is still not well defined, and further studies are needed to ensure the efficiency of the technique in this physical situation. The tests of the related phenomena that emerged in connections were evaluated by Wang et al [9], Andrade et al [10], Andrade et al [11], Andrade et al [12], Andrade et al [13] and Crivelaro et al [14]. Particularly with reference to reduction of pressure drop in flow, Brauner et al [15] has reported a correlation applied to heavy-oil/water two-phase flow in an annular flow pattern.…”

Ultrasonic and Heat Treatment of Crude Oils

“…The solution to these problems will allow reducing the cost of transportation of high-viscosity oil [3]. The methods of friction reduction include the flow of oil limited by a thin layer of water in the boundary area [4,5] and the use of various additives [6][7][8][9]. Methods of viscosity reduction include heating [10][11][12], ultrasonic treatment [13][14][15][16][17], emulsification of oil in water [18][19][20][21][22], and dilution (mixing with a thinning liquid with lower viscosity, for example, condensate from natural gas extraction, naphtha, kerosene, lighter crude oil, etc.)…”