Down-Hole Catalytic Upgrading of Heavy Crude Oil

Abstract

Several processing options have been developed to accomplish near-well-bore in-situ upgrading of heavy crude oils. These processes are designed to pass oil over a fixed bed of catalyst prior to entering the production well, the catalyst being placed by conventional gravel pack methods. The presence of brine and the need to provide heat and reactant gases in a down-hole environment provide challenges not present in conventional processing. These issues were addressed and the processes demonstrated by use of a modified combustion tube apparatus. Middle-Eastern heavy crude oil and the corresponding brine were used at the appropriate reservoir conditions. In-situ combustion was used to generate reactive gases and to drive fluids over a heated sand or catalyst bed, simulating the catalyst contacting portion of the proposed processes. The heavy crude oil was found to be amenable to in-situ combustion at anticipated reservoir conditions, with a relatively low air requirement. Forcing the oil to flow over a heated zone prior to production results in some upgrading of the oil, as compared to the original oil, due to thermal effects. Passing the oil over a hydroprocessing catalyst located in the heated zone results in a product that is significantly upgraded as compared to either the original oil or thermally-processed oil. Catalytic upgrading is due to hydrogenation and results in about a 50% sulfur removal and an 8° API gravity increase. Additionally, the heated catalyst was found to be efficient at converting CO to additional H2. While all of the technologies needed for a successful field trial of in-situ catalytic upgrading exist, a demonstration has yet to be undertaken.