An Examination of the Arkoma Foreland Basin and its Petroleum System through Burial and Thermal History Modeling
Lamb, Julianne Elizabeth 1989-
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The Arkoma Basin is a Carboniferous arcuate foreland basin that spans across west-central Arkansas into southeastern Oklahoma along the northern side of the Ouachita orogenic belt. High levels of thermal maturity are observed in the basin; however, the existence of an extensive post-Pennsylvanian/Permian surface unconformity has complicated the interpretation and correlation between basin sedimentation, subsidence, and exhumation. Through the calibration against maturity data provided by Southwestern Energy (SWN), 50 1D models are generated in a geologically coherent basin modeling study in the Arkansas portion of the Arkoma Basin. In each well, the synthesis of vitrinite reflectance and apatite fission track analysis (AFTA) data are used to estimate erosion and heat-flow variations in burial and thermal history reconstructions. To aid the estimation of heat flow in areas lacking data, a regional geothermal gradient map was generated from the corrected bottom-hole temperatures of 229 wells. Structure and isochore maps invoking depocenter migration and fault configurations were produced from formation tops picked at tectonically significant stratigraphic levels (foreland and pre-foreland basin settings). Within this study area, the calibrated burial and thermal history models indicate that nearly 9,000 to 19,000 feet of section have been removed. The estimated amount of eroded overburden is in agreement with a geologically realistic framework of previously established stratigraphic thicknesses. To avoid an unrealistic amount of eroded section, all models required a paleo-heat flow higher than the present-day value, with such differences increasing from south to north. A regional picture of the thermal maturity in the central-eastern Arkoma Basin is rendered upon combination of all reconstructed elements. Results are consistent with those suggested from previous authors in that patterns of increasing thermal maturity generally reflect those of increasing depth and erosion. In addition, this study indicates that there are no pronounced reoccurring patterns between anomalous thermal values and proximity to faulting. Possible reasons for anomalous data points can be attributed to vitrinite reflectance measurement error and variations in localized heat flow. However, most lateral variations in thermal maturity can be explained by estimates of erosion and a spatially reasonable change in heat flow.