Generation of Water-Soluble Organic Acids from Kerogen During Hydrous Pyrolysis: Implications for Porosity Development

T. I. Eglinton, C. D. Curtis and S. J. Rowland
Organic Geochemistry Unit, Department of Geology, Drummond Building, University of Newcastle upon Tyne, Newcastle NE1 7RU
Department of Geology, Mappin Street, University of Sheffield, Sheffield S1 3JD
Department of Environmental Sciences, Plymouth Polytechnic, Drake Circus, Plymouth PL4 8AA

Abstract: Concentrations of organic acids ranging up to several thousand parts per million have previously been found in oil-field waters. These acids are of interest because of their potential to enhance porosity by the dissolution of carbonates and aluminosilicates. They are believed to be generated from organic geopolymers (kerogen) in the late-diagenetic-early-catagenetic stage of thermal maturation.

During the course of artificial maturation experiments in which kerogens of varying type were heated in the presence of water (so-called ‘hydrous pyrolysis’) and different minerals, the distribution and abundance of low molecular weight water-soluble acids were determined by gas chromatography and gas chromatography-mass spectrometry. Preliminary results suggest that significant quantities of mono- and di-carboxylic acids are produced during hydrous pyrolysis. The amounts and types of acid appear to vary as a function of kerogen type, maturity and mineralogy. Implications of these findings regarding the development of secondary porosity are discussed.

Keywords: organic acids • kerogen • hydrous pyrolysis • porosity development

Mineralogical Magazine; October 1987 v. 51; no. 62; p. 495-503; DOI: 10.1180/minmag.1987.051.362.04
© 1987, The Mineralogical Society
Mineralogical Society (