THAI-CAPRI Process: Tracing Downhole Upgrading of Heavy Oil

摘要

Worldwide conventional oil production is expected to peak in the present decade, and the need to reevaluate the potential of heavy oil resources becomes ever more imperative. Steamflooding is reliable, but it is not very energy efficient. It also has large water requirements and does not significantly upgrade oil. In situ combustion (ISC), properly configured and operated holds considerable promise for both mobilizing and upgrading heavy crude oils with less energy expenditure. The THAI-CAPRI process appears to eliminate many of the pitfalls of conventional ISC and yield substantially upgraded oil. Although extensive documentation on the performance of the process is available, only basic upgrading data have been reported. The present study aims to quantify the extent and nature of oil upgrading during an experimental run that incorporates dry and wet phases over each toe-heel air injection (THAI) and THAI with catalyst (CAPRI) modes. Gas, oil, water and solid residue analyses are used to infer mechanisms of upgrading and to begin to gauge the economic (sweep and recovery) and environmental (gas emissions and produced water quality) impact associated with the eventual field operation of the process.