CAO, SONG, and STEFAN BACHU, Alberta Research Council, Edmonton, Alberta, Canada
A comprehensive approach was used in the study of geothermal regime and maturation in the Peace River arch area, western Canada, with the purpose of evaluating the potential for hydrocarbon resources. The present-day geothermal regime was determined based on bottom hole temperature, thermal conductivity, and radiogenic heat production data. Hydrogeological studies show that the heat transfer in the region is dominated by thermal conduction. Since the study area is relatively undisturbed and there are no large-scale changes in the thermal conductivity of sediments, the regional distribution of the geothermal gradient is controlled by the heat flow from the crystalline basement. The temperature distribution is controlled in addition by the thickness and thermal conductivity of the sedim nts.
The good control on the present-day geothermal regime allows a good evaluation of thermal maturation and calibration of models for thermal history reconstruction. A thermal inverse method, in which the paleoheat flux is estimated by optimization of the calculated to the measured vitrinite reflectance data, was used to reconstruct the thermal history of the area. The paleoheat flow in most of the region shows a warming-up trend with geological time. The paleoheat flow values on the arch were relatively higher than those off the arch, supporting the proposed rifting origin of the arch. Two regional thermal maturation trends are present for most of the source rocks in the area, one increasing from northeast toward the disturbed belt and another increasing from north to south. Both of the e trends reflect the structural control of the regional thermal maturation.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)