The use of an iron dispersed catalyst, derived from Fe-3(CO)(12), for extra-heavy crude oil upgrading using methane as source of hydrogen was studied. The upgrading reactions were carried out batchwise in a stainless-steel 300 ml Parr reactor with 250 ppm of Fe at a temperature of 410-420 degreesC, a pressure of 11 MPa of CH4, and a residence time of 1 h. In the presence of Fe(CO)(12), the reaction of Hamaca extra-heavy crude oil led to a reduction of two orders of magnitude in the viscosity (from 500 to 1.3 Pa s), 14% reduction in sulfur content, and 41% conversion of the > 500 degreesC fraction in the upgraded product with respect to the original crude. The iron catalyst was isolated from the coke produced from the upgrading reaction and was analyzed by XPS, EDAX, and Mossbauer spectroscopy. The results indicated the presence of a Fe-V mixed sulfide species with a composition ca. (Fe0.6V0.4)(z)S, where z is in the range 0.8-0.9. (C) 2003 Elsevier Science Ltd. All rights reserved.