Heavy Oil: Combustion-Tube Experiments Show Heavy-Oil-Production Increase With Addition of Catalyst
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 107946, "Increase Heavy-Oil Production in Combustion-Tube Experiments Through the Use of Catalyst," by M.A. Ramirez- Garnica, Instituto Mexicano del Petroleo; D.D. Mamora, SPE, Texas A&M U.; H.R. Nares and P. Schacht- Hernandez, Instituto Mexicano del Petroleo; A.A. Mohammad, Texas A&M U.; and M.C. Cabrera-Reyes, Instituto Mexicano del Petroleo, prepared for the 2007 SPE Latin American and Caribbean Petroleum Engineering Conference, Buenos Aires, 15–18 April. The paper has not been peer reviewed.
A catalyst was evaluated to aid heavy-oil combustion. The underlying objective is to increase the oil mobility inside the reservoir by use of the catalyst during combustion. The catalyst was evaluated in a combustion tube with 12.5°API heavy oil from the Gulf of Mexico (GOM). Use of this organometallic catalyst at low concentrations potentially can upgrade oil properties in situ, avoiding the cost of surface facilities to achieve the same goal.

Introduction
Reservoir exploitation is moving toward large reserves of heavy crude oil. Producing, transporting, and marketing this heavy oil presents many problems, including the inability of most refineries to accept heavy crude oils. Heavy crude oils could be more acceptable if they can be upgraded before being sent to refineries. In-situ combustion is one technique used to reduce oil viscosity. When combustion is combined with the use of a catalyst, the process is called in-situ catalytic upgrading.
Comprehensive studies of enhancing the combustion process by addition of metallic salts have shown that for some crude oils there is a favorable modification of the reaction kinetics. Salts, such as tin chloride or ferric nitrate, promote combustion of light oils, producing more-uniform combustion that occurs at a higher temperature. However, in another study, it was not possible to obtain sustained combustion of light oil without the addition of metallic salts. The full-length paper describes a combustion experiment using a combination of organometallic catalyst derived from either acetylacetonate or alkylhexanoate compounds and an air-injection system in a combustion tube. The hydrocarbon used was a 12.5°API heavy crude oil from the GOM. The catalyst was mixed with the heavy oil before the experiment. The objective of this study was to determine if this organometallic catalyst at low concentrations is able to improve heavy-oil recovery.

Experimental Method
The experimental setup comprised six main parts: fluid-injection system, combustion tube, fluid-production system, gas chromatograph, wet-test-meter system, and a data-recording system.

Fluid-Injection System.
The fluid-injection system consists of two parts, nitrogen injection and air injection. Both parts are independent (through 1/4-in. tubing) and are opened or closed to the system with valves in the control panel. The injected-nitrogen or -air rate is controlled by a mass-flow controller, installed before the injection pressure transducer. The 1/4-in. tubing line is connected with a fitting to a 1/8-in. tubing line, which is the gas inlet to the combustion tube.