Combustion Assisted Gravity Drainage (CAGD) Appears Promising

Abstract

Abstract In-situ combustion (ISC) is an effective thermal recovery process that provides an important alternative to steam injection. However, the conventional ISC process has many apparent failures, which are mainly related to inappropriate reservoir application and instability of the process. Operational difficulties like gravity segregation, air channeling, unfavorable air to oil ratio and low sweep efficiency affect the performance of ISC. Horizontal well air injection is an interesting concept, which through positioning of horizontal wells attempts to overcome the problems that make ISC challenging. Combustion Assisted Gravity Drainage (CAGD) is a new EOR process that use dual horizontal wells for injection of air and production of heavy oil. One important feature of this technique is that the properly oriented dual horizontal wells aid the development of combustion chamber and stabilized growth of the combustion front. In this research, detailed reservoir simulations are conducted to examine the performance of the CAGD process in comparison to other practiced thermal recovery methods like Steam Assistance Gravity Drainage (SAGD) and Toe to Heel air injection (THAI). The results reveal that CAGD process has the lower cumulative energy to oil ratio in comparison to other two methods and its oil production rate is comparable to SAGD. The research identifies CAGD as a potential alternative to ISC method.