THERMAL MATURATION HISTORY OF THE SIRTE BASIN, LIBYA

Abstract

The high degree of thermal maturity observed in shallow sediments in the western part of the Sirte Basin, Libya, requires higher geothermal gradients and/or thicker overburden in the past than exist today. The degree of thermal maturity of the Upper Cretaceous shales, the regional structure, and the subsidence history of the basin all indicate that over 3,000 m of section was removed from the western flank of the basin by uplift and erosion in the mid‐Tertiary. Vitrinite reflectance values in wells suggest that gradients of 1.6d̀FC/100 ft to 1.8d̀FC/100 ft existed in the western region at the time of peak thermal activity, in contrast with a general basin average of 1.2 d̀F/ l00ft