--> Rock-Eval Pyrolysis Data Analysis and Kerogen Kinetics Comparison of Selected Producing and Potential Shale Gas Plays in Canadian Sedimentary Basins

AAPG Annual Convention and Exhibition

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Rock-Eval Pyrolysis Data Analysis and Kerogen Kinetics Comparison of Selected Producing and Potential Shale Gas Plays in Canadian Sedimentary Basins

Abstract

Petroleum resource development from shale reservoirs is capital intensive. A quick and reliable evaluation of shale resource play and early identification of “sweet spots” are critical to competitive advantages. Since organic-rich shales are both source rock and reservoir, generation capacity, kerogen kinetics and maturity are the essential elements in play evaluation. Rock-Eval pyrolysis has been widely accepted by the industry as a useful tool as the analytical results can provide a quick, easy and cost effective way for source rock evaluation. However, there are misconception and confusion in applying the Rock-Eval data to source rock evaluation due to difference in the maturity status of individual samples, and the embedded maturity variation could lead to unsatisfactory results if mishandled in data interpretation. Appropriate interpretation from a perspective of hydrocarbon generation kinetics may shed light for a better understanding of thermal maturation and generation capacity of the source rock under examination. This study examines Rock-Eval pyrolysis datasets from 23 source rock systems of selected producing and potential shale gas plays in Canada through application of newly developed methods or tools for source rock evaluation. Kerogen kinetics was examined using a data-driven model designed for geologists and entirely based on Rock-Eval data. The hydrocarbon generation potentials are determined via restoration of initial hydrogen index and TOC. This study also proposes the use of a dimensionless plot of S2 versus TOC to remove the effect of different maturities on determining type of kerogens in data interpretation. A comparison of organic rich shales in Canadian sedimentary basins under this study reveals large variation in hydrocarbon generation capacity and kerogen kinetics even for the same types of kerogen. A comparison of the source rock kinetics of major producing shale gas plays in Canada with those from the United States shows similarities and differences in kerogen compositional features of the hosting shale reservoirs. This presentation discusses various methods, presents the results and demonstrates the innovative approaches of studying oil generation kinetics and resource potentials using conventional Rock-Eval data without involving specially designed and costly laboratory pyrolysis experiments.