Heavy Oil and Bitumen Recovery Using Radiofrequency Electromagnetic Irradiation and Electrical Heating: Theoretical Analysis and Field Scale Observations

Abstract

Heavy-oil and bitumen recovery from difficult geological media such as deep, heterogeneous and high shale content sands and carbonates, and oilshale reservoirs requires techniques other than conventional thermal and miscible injection methods. Materials in oil reservoirs (formation water, crude oil, oil-water emulsions, bitumen and their components like resins, asphaltenes, and paraffin) are non-magnetic dielectric materials with low electrical conductivity. If the electromagnetic field can be created to change these properties, electro-thermo controlled hydrodynamics could improve the displacement and recovery of heavyoil/bitumen. This paper deals with the recovery improvement of heavy-oil/bitumen by Radio-Frequency (RF) Electromagnetic (EM) radiation. 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 containing reservoirs to generate heat and eventually improve recovery mainly due to the reduction of oil viscosity. The recovery mechanisms and the dynamics of the RF-EM heating process were analyzed for several field scale applications in Russia. In the Yultimirovskaya tar sand deposits, RF-EM energy was transmitted from the RF-EM generator, located at the surface, into the formation by a coaxial system of the well pipes. Another field example analyzed was the RF-EM stimulation process in several wells of the Mordovo-Karmalskaya tar sands performed in the 1980s. It was observed that the formation was heated to the temperature which was sufficient for injection of oxidant (air) to initiate fire flooding.Then, a mathematical model of this process was presented with a sample exercise. Some data needed for this exercise were obtained from the field tests evaluated.Field tests proved the efficiency of the RF-EM stimulation of heavy oil / bitumen deposits with low water cut values (in operating production wells with water cut <30% on early field development stages). Numerical simulations suggest that bottomhole temperature and heat/mass transfer effects in the reservoir can be controlled by setting the output performance of the RF generator and by the difference between the reservoir and bottom-hole pressure.

The Prospect of Electrical Enhanced Oil Recovery for Heavy Oil: A Review

“…Electromagnetic radiation of radiofrequency driven from the antenna located in the wellbore near to reservoir layer containing heavy oil (Bera & Babadagli, 2017;Davletbaev et al, 2010;Saeedfar et al, 2016). A considerable distance into the previous oil-carrying layers will be penetrated by electromagnetic energy in which electromagnetic will be either absorbed or removed and converted into thermal energy that is about 5 kW or even the highest of 100 kW (Oloumi & Rambabu, 2016).…”

Evaluation of Induced Thermal Pressurization in Clearwater Shale Caprock in Electromagnetic Steam-Assisted Gravity-Drainage Projects

“…RF-EM radiation has a short-range effect, and this is the reason it is mostly referred to as "RF-EM stimulation." Although its application in bitumen deposits is questioned, a few studies, such as Davletbaev et al (2010), proved its efficiency in bitumen deposits with low water-cut values (i.e., water cut <30%); they also suggest both the use of RF-EM stimulation in heavy-oil production wells on the early field-development stage and the conversion of RF-EM stimulation to electric heating in production wells when the water front from the injection wells reaches the production zones.…”

Effects of Electrical and Radio-Frequency Electromagnetic Heating on the Mass-Transfer Process during Miscible Injection for Heavy-Oil Recovery

“…Electrical and electromagnetic heating can be considered as an alternative to conventional thermal methods for heavy-oil and bitumen recovery. The results of experimental studies on the radio-frequency electromagnetic (RF-EM) field irradiation and electrical heating are presented in several papers. − Theoretical approaches for the estimation of heavy-oil recovery performance were also presented, − as well as the field tests in Russia, Canada, and the United States. ,− Field tests in Russia − showed that RF-EM is highly effective with fields having less than 30% water encroachment because the EM field in the RF range has almost no effect on the water because the resonance effect for water is in the microwave range. However, a large water content (>30%) has certain impacts and created technical difficulties in the oil reservoir, and the RF-EM technique was not recommended.…”

“…The results of experimental studies on the radio-frequency electromagnetic (RF-EM) field irradiation and electrical heating are presented in several papers. − Theoretical approaches for the estimation of heavy-oil recovery performance were also presented, − as well as the field tests in Russia, Canada, and the United States. ,− Field tests in Russia − showed that RF-EM is highly effective with fields having less than 30% water encroachment because the EM field in the RF range has almost no effect on the water because the resonance effect for water is in the microwave range. However, a large water content (>30%) has certain impacts and created technical difficulties in the oil reservoir, and the RF-EM technique was not recommended. In certain circumstances, such as deep, tight, or heterogeneous sand/carbonate reservoirs or oil shales, it is the only solution because steam injection is not applicable as a result of injectivity problems or high clay content.…”