Characterization of the sedimentary thermal regime along the Corsair growth-fault zone, Texas continental shelf, using corrected bottomhole temperatures

Abstract

Temperatures of deep (> ∼3 km [1.8 mi]) sediments along the Corsair growth-fault zone in the Texas continental shelf are elevated relative to those off the fault zone. This observation is based on a compilation of nearly 400 bottomhole temperatures (BHTs) obtained from about 230 wells widely distributed across the continental shelf. The BHTs have been individually corrected for the thermal disturbance associated with drill-fluid circulation. The isotherm of 140°C (284°F) derived from the corrected BHTs shows more or less continuous peaks along the fault zone. Thermal gradients in the depth range of 3 to 5 km (1.8 to 3.1 mi) shows higher values along the fault zone than off the fault zone. These trends are similar to the previous observations made along the Wilcox growth-fault zone in the Texas coastal plain. Previous studies suggest that the faults of the Wilcox system serve as the conduits for hot fluids expelled from deep, overpressured sediments. A similar mechanism may explain the elevated temperatures along the Corsair fault zone.