Shale oil and gas exploration potential in the Tanezzuft Formation, Ghadames Basin, North Africa

Abstract

The Silurian Tanezzuft Formation ‘hot shale’ in North Africa is a high-quality source rock and a major contributor to the oil and gas reserves of the Paleozoic Ghadames Basin. This hot shale has similar sedimentary characteristics to those of the Silurian Longmaxi Formation shale in the Sichuan Basin in China, which is a proven prolific source of shale gas. In this study, the oil and gas accumulation conditions and sedimentary characteristics of the Tanezzuft shale are compared with those of the commercially exploited Longmaxi shale and the Marcellus and Barnett shales (North America), and criteria for shale oil and gas potential in the Tanezzuft shale are established from these commercially exploited shales. For the Tanezzuft shale, the net pay thickness of effective source rock, total organic carbon, thermal maturity and burial depth, and the locations of faults in the Ghadames Basin are analyzed and mapped. The distributions of these variables are then used to predict the distribution of shale oil and gas with respect to the established criteria. It is shown that the Tanezzuft shale has significant potential for the production of shale oil and gas; in particular, the northeastern and southwestern slopes of the Ghadames Basin are the most favorable in terms of prospective shale oil and gas exploration.