Heat flow and thermal history of the Anadarko Basin and the western Oklahoma Platform

The average geothermal gradient in the Anadarko Basin and the Oklahoma plat form estimated from 856 corrected bottom-hole temperatures (BHTs) is 21 deg rees C/km. Analysis of previously published thermal maturation data indicat es that the Anadarko Basin has undergone from 1 to 3 km of erosion starting about 40 to 50 Ma. The average thermal gradient at the time of maximum bur ial was in the range of 22 to 25 degrees C/km. There is no evidence that th e thermal state of the Anadarko Basin has changed significantly since the l ate Paleozoic (250 Ma). To estimate heat flow in the Anadarko Basin and the Oklahoma Platform, we made 652 thermal conductivity measurements on drill cuttings from 9 oil and gas wells. All measurements were corrected for the effects of anisotropy, temperature, and porosity. Matrix conductivities per pendicular to bedding at 22 degrees C range from 1.7 W m(-1) K-1 fdr Permia n age sandstone and shale, to 2.6 W m(-1) K-1 for Devonian-Silurian age lim estone and shale. In-situ thermal conductivities vary from 1.3 W m(-1) K-1 to 1.9 W m(-1) K-1. Estimated heat flow (+/-20%) ranges from 30 mW/m(2) to 42 mW/m(2), with a mean of 36 mW/m(2). We found no evidence for heat flow t o increase significantly from the Anadarko Basin in the south to the Oklaho ma Platform to the north. These results contradict a previous study which f ound heat flow increases from south to north, with heat flow in the Oklahom a Platform as much as 50% greater than heat flow in the Anadarko Basin. At the present time, we do not know if these differences are related to spatia l variations or reflect methodological errors. If our results are averaged with those reported in previous work, mean heat flows in the Anadarko Basin and Oklahoma Platform are 39 mW/m(2) and 51 mW/m(2), respectively. (C) 199 9 Elsevier Science B.V. All rights reserved.