Artificial Maturation of Organic Matter from Recent Venezuelan Sediments |
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| Authors: | Méndez M J Scherer W |
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| Institution: | (1) Instituto de Ciencias de la Tierra, U.C.V, Caracas, Venezuela;(2) PDVSA-Intevep, P.O. Box 76343, Caracas, 1070A, Venezuela |
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| Abstract: | Laboratory simulation of the catagenesis of organic matter in sedimentary rocks has been used to provide an understanding of the processes involved in petroleum generation. Several of these studies have focused on the thermal evolution of organic matter (OM) present in Recent sediments. This study examines the geochemical characteristics and experimental thermal evolution of primary organic matter from two organic facies that are thought to be major contributors to Venezuelan hydrocarbon source rocks. A third facies, generally considered unimportant for petroleum formation, is used to contrast the experimental results. Hydrous pyrolysis maturation experiments were performed for three intermediate temperatures. The products of the final 330°C stage are shown in this paper because they best illustrate the changes in the OM during catagenesis. Results from the hydrous pyrolysis experiments show that at 280°C and higher all three samples yield liquid hydrocarbons similar in composition to natural crudes and the transformed organic matter is similar to kerogen that occurs in natural source rocks. Chromatograms from the saturated fraction of extracts at 330°C are similar to natural crudes with respect to n-alkane distribution and abundance of  beta; and beta;alpha; hopanes. The only difference seems to be the relative abundance of 22R over 22S isomers, which indicates immature oil. This is in contrast to indications from the R
o and T
max parameters measured on the accompanying kerogen. |
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| Keywords: | Recent sediments hydrous pyrolysis biomarkers diagenesis catagenesis organic facies peat Venezuela |
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