SUNDARARAMAN, PADMANABHAN, Chevron Canada Resources, Calgary, Alberta; and T. I. ROBL, Center of Energy Research, Univ. of Kentucky, Lexington, KY

ABSTRACT: Use of Activation Energy of Maceral Concentrate in Predicting Product Composition ofGenerated Oil

Petrographically, kerogen of a source rock may contain a mixture of macerals. For example, the Devonian New Albany Shale kerogen consists of a mixture of liptinite, bituminite (amorphous organic matter) and vitrinite. These macerals have different compositions and hence have different reactivities. Because of this difference in reactivity they decompose at different rates. In addition to these reactivity differences, the composition of the product generated from each maceral is different.

This paper describes our initial attempt to characterize the reactivity of kerogen consisting of liptinite, bituminite, vitrinite and inertinite and predict the composition of products with extent of Conversion. The method consists of separating the macerals of a kerogen by density gradient centrifugation and estimating their individual reactivities using a micro pyrolysis technique.

Activation energy distributions of maceral concentrates from New Albany Shale kerogen were estimated by micro pyrolysis. Liptinite is dominated by a single activation energy, whereas, bituminite and a mixture a bituminite and vitrinite show broader activation energy distributions. Use of this information, along with the product composition of pyrolyzate obtained from these macerals, in quantitative basin evaluation shows that the product composition changes with the extent of conversion. Earlier generated products contain relatively higher proportions of aromatic hydrocarbons and the aromatic/aliphatic ratio decreases with increasing conversion.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.