Geothermal Gradients in the Northern Western Desert, Egypt as Deduced from Bottom-Hole-Temperature and Aerogravity Data

Abstract

The Western Desert of Egypt covers two thirds of the whole area of Egypt. Its northern part represents the second most promising areas of hydrocarbon potential after Gulf of Suez province. So, most of the explorations were focused only on hydrocarbon and water resources and limited work has been done on geothermal potentialities. Bottom-hole temperature (BHT) records at 149 deep oil wells (2000 – 4500 m) were used for evaluating the geothermal resources in Northern Western desert of Egypt. Correction was applied on the BHT data to obtain the true formation equilibrium temperatures that can provide useful constraints on the subsurface thermal regime. On the basis of these corrected data, temperature gradient was computed for the linear sections of the temperature-versus-depth at each well. Although the Northern Western Desert of Egypt has low regional temperature gradients (30 oC/km), some local geothermal potential fields were located (40 – 50 oC/km). Heat flow at each well was also computed by combining sets of temperature gradient and thermal conductivity data. Aerogravity data was used for delineating the subsurface structures and tectonic framework of the Northern Western Desert. Geothermal gradient was integrated with corresponding gravity value at each well location using Artificial Neural Network (ANN) method in order to predict the geothermal regime at localities where no boreholes exists. The result is new geothermal gradient map of the Northern Western Desert developed from gravity and BHT logs data.