METHOD FOR CORRECTING BOTTOMHOLE TEMPERATURES ACQUIRED FROM WIRELINE LOGGING MEASUREMENTS AND CALIBRATED FOR THE ONSHORE GULF OF MEXICO BASIN, USA

The U.S. Geological Survey (USGS) has developed a statistically robust and repeatable method for determining corrected bottomhole temperatures (BHT) acquired from wireline logging measurements in the borehole environment. This method was developed and calibrated for the onshore Gulf of Mexico basin, USA to support assessments of petroleum resources in this basin. The geographic and stratigraphic distributions of these measurements allows corrected BHT data to be used to characterize the subsurface thermal regimes. Wireline logging BHT measurements are abundant yet notorious for underrepresenting true formation temperatures. A variety of temperature correction methods are available for other geologic basins globally; however, these methods are not directly applicable to the onshore Gulf of Mexico basin. Due to the geological complexity of the onshore U.S. Gulf Coast region, especially in the presence of the Jurassic Louann Salt, a BHT correction method specifically designed for this petroleum province is imperative. The empirically derived method is calibrated for twelve separate subregional areas within the onshore U.S. Gulf of Mexico basin, including the (1) Houston embayment salt basin, (2) Rio Grande embayment, (3) north Louisiana salt basin, (4) southern Louisiana salt basin, (5) Monroe uplift, (6) La Salle arch, (7) Jackson dome, (8) east Texas basin, (9) Sabine uplift, (10) Judge Digby field, (11) Mississippi salt basin, and (12) southern Mississippi vicinity. Each of the twelve subregional areas exhibit a distinct temperature profile; consequently, a BHT correction was developed for each area to capture the thermal complexities of the onshore Gulf Coast region. This investigation also compared the USGS correction method to several other published correction methods which are commonly applied to the Gulf Coast region. Additionally, geothermal gradients for these twelve subregional areas were calculated, and results indicate that onshore Gulf Coast geothermal gradients range from 1.89 F/100 ft in warmer thermal regimes of the Sabine uplift area to 1.39 F/100 ft in cooler thermal regimes found in the southern Louisiana salt basin.