Thermal Conductivity Estimates in the Niger Delta using Lithologic Data and Geophysical Well Logs

Abstract

Thermal rock properties and heat flow were determined from two hundred and sixty wells in the Niger Delta. The new thermal data provides new aspects for the determination of heat flow and for thermal evaluation of basins. A map has been constructed using lithologic data and geophysical well logs. The thermal conductivity for sand and shale, the predominant lithology in the Niger Delta shows wide variations from well to well. In the Benin formation, thermal conductivity has an average of 8 W/mK. The lowest values are found offshore westward, while highest values occur northward. The conductivity values however decreases approaching the marine paralic section with an average value of 5 W/mK, this is the region of interest however. The thermal conductivity values have been used in calculating heat flow. A significant regional trend of relatively low heat flow at the central part (20 – 30 mW/m2), increases both seaward and northward (40 - 55 mW/m2) is observed in the map area. The lowest heat flow is observed in the central part of the study area. The highest heat flow is in the northern part, with values exceeding 50 mW/m2. Knowledge of thermal properties has direct relevance for hydrocarbon exploration.