Production Increase of Heavy Oils By Electromagnetic Heating

Abstract

Abstract Several methods of accelerating oil flow by applying heat from the wellbore to the reservoir have been successfully field tested. However, it appears that the possibility of heating by high-frequency radiation has not been extensively investigated, either theoretically or experimentally The concepts involved are discussed and a mathematical model is developed in order to evaluate the temperature distributions and other physical effects resulting from the radiation of electromagnetic energy into an oil reservoir. Flow performance is compared to the unheated case on the basis of a steady-state temperature distribution, which is derived. The results of a pre-steady-state transient flow condition are also presented. Calculations based on the mathematical model developed indicate that further work is warranted to prove or disprove the feasibility of this method of stimulation. A brief discussion of completion and engineering problems is included. Introduction From time to time, the technical literature has made reference to heat stimulation by the radiation of electromagnetic energy from the wellbore. A Russian paper(1) touched on one aspect of the subject, and compared electromagnetic and contact heating for a shut-in well, using a spherically symmetric model. The possibilities of concurrent flow and power input were not discussed. It should be emphasized that this paper deals not with conduction or induction, but true radiation, as exemplified by the output of a short-wave radio station. In the broadest terms, electromagnetic effects are exhibited from the lowest frequencies (e.g. 60 cycle and lower) to the very highest (X-rays, gamma radiation, etc.). For the practical purpose of wellbore heating, however, the following discussion should be viewed in terms of those frequencies at which high power can be generated on a continuous basis. At the present, this includes frequencies up to about 20000 megacycles per second. Figure 1 shows schematically the mode of operation envisioned for radiation heating.