Abstract: Numerical Modeling of Heat Flow in the Arkoma Basin

The Arkoma Basin is an E-W-trending foreland basin that formed in response to the late Paleozoic Ouachita orogeny (Thomas, 1985) and is an excellent example of prolific natural gas production from strata considered to be overmature (R[o] greater than 3.0). An expected northerly trend for thermal gradient and fluid expulsion through Cambrian sandstones, related to south-to-north basin closure, was recognized by Bethke et al. (1988). However, there is an unexpected, eastward component to increasing thermal maturity in Carboniferous strata (Houseknecht et al., 1987). This trend cannot be explained by sedimentary or tectonic burial depth, nor by the presence of igneous intrusions. Houseknecht et al. (1987) hypothesized that the facies distribution and orientation of regional faults, in combination with loading or overpressuring, would induce upward and eastward fluid flow through the foreland basin. Transfer of heat from the deep basin by this mechanism could potentially explain not only the high overall thermal maturity of the basin but also the trend of increasing R[o] values to the east.

The purpose of this study is to explore whether east-west facies changes or similarly oriented structures (including faults, folds, cleavages, and fractures) could act as conduits to bring hot basinal fluids into shallow depths.

The majority of the work will involve using the two-dimensional numerical code Basin2 (Bethke, 1985; Bethke et al., 1993; Hayba and Bethke, 1995) to simulate the heatflow through the basin. This code accounts for conductive and convective transport of heat in response to basin loading.

In conclusion, this study will improve our understanding of the thermal evolution of the Arkoma basin as well as the mechanisms of hydrocarbon preservation under conditions of high thermal maturity. 

AAPG Search and Discovery Article #90940©1997 AAPG Foundation Grants-in-Aid