Geothermal Exploration in Nigeria

Abstract

The geological structure of Nigeria influences geothermal exploration extent within each geological province. Sedimentary basins in Nigeria have been explored for hydrocarbons for several decades, thus the oil companies collected large subsurface temperature data basis. But not much is known about geothermal conditions within Nigerian Precambrian crystalline province.On the basis of BHT data from oil wells it has been found that geothermal gradient in Niger Delta ranges from 1.3 to 4.7°C/100m and in Anambra Basin (directly to the north) it can reach 5.5°C/100m. Exploration for geothermal energy in northern Nigeria based on shallow water wells (down to 500 m deep) was carried out over 20 years ago. Research was concentrated mainly on geothermal conditions within Sokoto and Nigerian part of Chad sedimentary basins, where relatively high geothermal gradients were found: 7.6° and 5.9°C/100m respectively. In north-western Nigeria the geothermal anomaly of Sokoto basin extends to the Niger territory.The other aspect of geothermal exploration in Nigeria is investigating of the thermal springs and seepages, which occur mainly within sediments of the Middle and Upper Benue Trough. The water of the warmest springs in that area: Akiri and Ruwan Zafi have the temperature about 54°C and it suggests the occurrence of some geothermal anomalies. So far, there is probably the only one (direct) geothermal energy utilisation site in Nigeria. It is a swimming pool where water from Ikogosi warm spring (37°C) is used. It is located in south-western part of the country, in Ekiti state.

Curie Depth and Surface Heat Flow Estimation from Anomalous Magnetic Blocks in the Lower and Part of Middle Benue Trough and Anambra Basin

“…It is interesting to observe that volcanism in the region is inseparable from the anticlinal folds. In the region, a hot spring (i.e., middle Benue spring) with the highest temperature of around 53.5 °C was recorded [67] .…”

A Short Review on The Application of Potential Field Methods for Geothermal Energy Exploration

“…The average aeromagnetic data interpretation revealed that the geothermal gradient from the Chad Basin varied from 3.00 to 6.44 °C/100 m, the thermal conductivity varied from 0.58 to 4.21 WmK -1 , while the heat flow ranged from 45 to 90 mWm -2 , respectively (Kwaya et al 2016). Meanwhile, the gravity data interpretation showed that the geothermal reservoirs in the Chad Basin are housed within the depth varying from 23 to 26 km (Kwaya and Kurowska, 2018). The geothermal anomalies in the basin are as a result of the thinned crust resting above the fault-confined graben and horst networks from the tectonic activities.…”

“…The spring flows from an approximate depth of 700 m below the earth surface. It is believed to be the only juvenile water in Nigeria (Garba et al 2012) (Kwaya and Kurowska 2018). The identified geothermal reservoirs will boost the Nigerian energy mix if the government and other concerned agencies could look into the installation of geothermal binary power generation system for the production of electricity, since there is no active volcanic domain in Nigeria that could be adopted for other applications of geothermal energy other than electricity.…”