Abstract

Production improvement of heavy-oil/bitumen recovery by using Radio-Frequency (RF) Electromagnetic (EM) fields present great practical interest. Most of the material of the oil industry - oil-saturated reservoir, formation fluid, oil, bitumen and then- components (resins, asphaltenes, paraffin, oil-water emulsion, high-viscosity and extra-heavy crude oil) in their electromagnetic properties are non-magnetic dielectric materials with low electrical conductivity. If the electromagnetic field impacts these materials, electro- thermo- and hydrodynamic phenomena take place. The RF-EM fields in the form of waves can penetrate deeply enough - from fractions of a meter to several hundred meters - into oil and gas technological working media

The paper deals with the impact of EM fields on the heavy-oil/bitumen sand deposit and electro-, thermo- and hydrodynamic processes control for enhanced oil recovery. The present paper discusses the technique of RF-EM heating of an oil-bearing layer combined with solvent injection, aimed at increasing heavy and extra-heavy oil recovery rate. Such combined technology expands the displacement area and allows a deeper heating of the layer. This method increases the technical and economic efficiency of field development by treating a producing well in three stages. At the first stage, the well operates as in injector to inject a solvent with simultaneous RF-EM exposure. At the second stage, the well is suspended to ‘stay' without any treatment. Finally, the well is re-commissioned to produce from the layer.

The paper presents a mathematical model for this three-stage iterative process, which describes transfer of mass and heat within the ‘well/ reservoir/ rock environment' system. A numerical simulation was also employed to study the effect of heavy oil production and the relative energy balance. The model estimates the optimum solvent volume and stage duration; the paper also gives a comparative analysis of calculation results for two cases: the one using the suggested combined technique, the other using constant heating without solvent injection.

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