On a Probable Catalytic Interaction between Magnetite (Fe3O4) and Petroleum

Magnetic and nonmagnetic iron compounds were detected as part of asphaltene deposits formed on tubing wall surface. To shed light on the probable role of the iron compounds in the formation of such deposits, magnetite (Fe3O4), one of the intrinsic components of the iron oxide multilayer scale of any carbon steel surface, was contacted with crude oil at 170 °C, a temperature similar to that of the bottom well, and subsequently aged at room temperature. Characterization of the samples was made by using XRD, Mo¨ssbauer, IR, TGA, EDS, and microscopic (SEM and TEM) techniques. Small amounts of new iron phases, magnetic (oxidized magnetite) and nonmagnetic (iron oxyhydroxides), an increase in the content of CdC and C-O bonds of the organic phase, and an increase of the thermal stability of the organic phase indicated the formation of iron complexes of Fe ions and FeOOH with the oxygen functionalities

Formation of petroleum organic deposits on steel surfaces

An adhered organic deposit, formed within the petroleum well on the steel surface of the tubing walls, was systematically characterized following a sequence of bulk and surface techniques. The results allowed the identification of the tubing wall and its internal surface structures. As a consequence of the contact with sulphur-bearing compounds such as H2S and brine from petroleum, the pre-oxidized steel surface was modified by non-stoichiometric iron compound formation. These new iron phases favour adsorption and chemisorption of the petroleum polar compounds on the steel surface. Copyright 2002 John Wiley & Sons, Ltd

DEPOSITION OF PETROLEUM HEAVY ORGANIC COMPOUNDS ON A LOW CARBON STEEL TUBING

Reduction of petroleum wells production is often observed and related to the presence of solid deposits adhered on the internal wall of the tubing. A piece of tubing with organic material adhered on its surface was recovered from a Mexican southeastern region well. Its composition and morphology was studied applying scanning electron microscopy with X-ray energy dispersion spectroscopy (SEM-EDXS), X-ray diffraction (XRD) and reflection Fourier Transform Infrared Spectroscopy (FT-IRS). High-condensed hydrocarbons with hydroxyl and carboxyl functional groups and 6.4 wt% total sulfur were found. The adhered-material morphology suggests vitreous solid structure usually identified in polycyclic aromatic compounds. Iron (II, III) oxides and nonstoichiometric sulfides are present; the last, as a corrosion product obtained in petroleum with low H 2 S concentration. Pyrrhotite ( Fe 1-x S ), which exhibits a nonstoichiometric structure, was reported as the active phase of iron oxide catalysts in hydrogen interchange processes. </jats:p