Modern Techniques to Minimize Catalyst Deactivation Due to Coke Deposition in Catalytic Upgrading of Heavy Oil In Situ Processes

One of the promising technologies to concurrently recover and upgrade heavy oil is the novel Toe-to-Heel Air Injection (THAI) combined with CAtalytic upgrading PRocess In situ (CAPRI) process. With the add-on CAPRI, the produce oil is partially upgraded to medium or even light oil with American Petroleum Institute (API) gravity increase in range of 3°–7°, viscosity reduction 70–90% and 70–85% recovery of original oil in place. But the catalyst suffers severe deactivation due to active sites coverage and pore blockage caused by coke and heavy metal depositions. This review explores methods of extending catalyst longevity in in situ catalytic upgrading of heavy oil during THAI process to bridge the gap that has been left void for a long period of time, and to serve as a guide for the low-cost catalyst design in order to improve process economics. To direct future research, several approaches such as the use of a structured guard bed, nano-sized catalyst, engineered catalyst support and pore sizes, graded catalyst bed, hydrogen addition, hydrogen-donor solvents, and steam environments have been identified and explored to suppress coke formation during catalytic upgrading of heavy oil. In addition to considerations for catalyst design for in situ upgrading applications, the study also discusses the operation conditions and upgrading environment that minimize coke formation and optimize catalyst longevity in the THAI–CAPRI process and similar processes such as steam assisted gravity drainage (SAGD). [Figure not available: see fulltext.]