Calculation of the thermal efficiency of a steamflooding process in stratified reservoirs

Abstract

Heavy oil reservoirs show a predominant importance because they are associated with the largest reserves in the world. For this reason, it has resulted in the development of enhanced recovery techniques such as steamflooding, to facilitate the production of heavy oil. However, the common practice has evidenced the presence of shale within producing formations, which negatively affect the efficiency of thermal recovery processes.
This study was conducted from the construction of simulation conceptual models, with different spacing between wells and different sand-shale ratio, with the purpose of analyze how much of the energy supplied to the producing formation
through the steam is being exploited by the same, and what portion has been trapped by shales. Results show that the thermal efficiency of the process is affected for the presence of shale formations, mainly when these are of great thickness, which has reflected in the index productivity low. Moreover, it was observed that decreasing the spacing between wells, allowed best recovery factors due to that steamflooding is more efficient. The final results of this investigation led to development of correlations that allow the calculation of the thermal efficiency of a steamflooding process in heavy oil reservoirs with shales intercalated. These correlations may be applied in subsequent studies as long as characteristics of models going to be evaluated are similar to in the models in this study. With this work it is sought to make a contribution to the industry in the area of enhanced oil recovery for producing high viscosity oil.