Investigation of the Thermal History of the Delaware Basin Using Carbonate Clumped Isotope Thermometry
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I utilized carbonate clumped isotope thermometry to explore the thermal history of the Delaware Basin, West Texas, USA. Carbonate wellbore cuttings from five oil/gas wells across the basin yielded apparent clumped isotope temperatures (T(Δ47)) ranging from 26°C to 305°C, interpreted to reflect a combination of initial precipitation/recrystallization temperature and solid-state C-O bond reordering during burial. Dolomite samples record lower apparent T(Δ47)s than calcite, interpreted to reflect greater resistance to reordering in dolomite. Using burial curves provided by the Chevron Center of Research Excellence (CoRE), I created unique time-temperature histories by linearly applying a geothermal gradient. Using two different Thermal History Reordering Models (THRMs), I modeled the extent of solid-state C-O bond reordering to iteratively find the time-averaged best-fit geothermal gradients (BFGGs) for each of the five wells. Results of this modeling suggest that the shallower, southwestern portion of the study area experienced roughly 40% higher geothermal gradients throughout the sediment history (40-45 °C/km) than did the deeper, southeastern portion (30-35 °C/km), with the northern portion experiencing intermediate geothermal gradients (35-40 °C/km). This trend agrees with the observed gas/oil ratios of the Delaware Basin, increasing from east to west. I furthermore compared my modeled maximum burial temperatures to previously published vitrinite reflectance data in two of the wells, and observe a good agreement in the maximum burial temperatures between the two methodologies.
Naylor, Howard Nathan (2018). Investigation of the Thermal History of the Delaware Basin Using Carbonate Clumped Isotope Thermometry. Master's thesis, Texas A & M University. Available electronically from