Techniques to Improve the Use of Microwave to Produce Heavy Oil Reservoirs: Numerical Study

Abstract

Abstract The objective of this work is to improve the efficiency of using microwave to produce heavy oil formations. Thermal technologies are proven to be the most efficient for heavy oil recovery, with steam being the most widely used technique. However, steam injection has many limitations. The use of microwave as an alternative thermal source provides in-situ heating to overcome several challenges; but heat penetration depth is a challenging area that limits its applicability. This paper presents a numerical study to explore the factors that affect heat generation and penetration depth of this microwave-assisted technique. In addition, it presents and compares four different solutions to improve its performance. A commercially available thermal reservoir simulator is used to model the use of microwave to produce heavy oil reservoirs. In this study, a heavy oil formation gets exposed to microwave irradiations at different frequencies and power levels. Production rate, cumulative production, temperature profile around the wellbore, and penetration depth of using microwave alone and in combination with four improvement techniques are monitored and analyzed. The improvement techniques include creating a network of producers and microwave wells, cyclic microwave/production operation, combining microwave with water injection, and the use of activated carbon as a microwave enabler. The results of this study shows that microwave frequency is the main factor that controls heat penetration depth. On the other hand, power level affects significantly the amount of generated heat. This work also shows that combining microwave with any of the proposed solutions would increase the cumulative oil production by 14 to 150%. Their performance is affected by many factors related to the targeted reservoir, heavy oil properties, and microwave specifications; however, in this paper we focus on microwave power-level, frequency, and other factors related to each of the presented techniques. Using microwave is one of the solutions to produce heavy oil reservoirs especially if other techniques are more difficult and costly to apply. The proposed solutions improve the performance of this microwave-assisted technique and overcomes some of its major challenges. This will unlock huge heavy oil resources especially in deep and offshore reservoirs.