A spatial analysis for geothermal energy exploration using bivariate predictive modelling

Andongma W Tende,Jiriko N Gajere,Mohammed D Aminu

doi:10.1038/s41598-021-99244-6

Abstract

The development of predictive maps for geothermal resources is fundamental for its exploration across Nigeria. In this study, spatial exploration data consisting of geology, geophysics and remote sensing was initially analysed using the Shannon entropy method to ascertain a correlation to known geothermal manifestation. The application of statistical index, frequency ratio and weight of evidence modelling was then used for integrating every predictive data for the generation of geothermal favourability maps. The receiver operating/area under curve (ROC/AUC) analysis was then employed to ascertain the prediction accuracy for all models. Basically, all spatial data displayed a significant statistical correlation with geothermal occurrence. The integration of these data suggests a high probability for geothermal manifestation within the central part of the study location. Accuracy assessment for all models using the ROC/AUC analysis suggests a high prediction capability (above 75%) for all models. Highest prediction accuracy was obtained from the frequency ratio (83.3%) followed by the statistical index model (81.3%) then the weight of evidence model (79.6%). Evidence from spatial and predictive analysis suggests geological data integration is highly efficient for geothermal exploration across the middle Benue trough.

Highlights

The development of predictive maps for geothermal resources is fundamental for its exploration across Nigeria
Since the 1950s, Nigeria has been heavily dependent on fossil fuels and hydro-electric power as the foremost source of energy and by 2015 a total of 4000 MW was generated for a population of over 170 million[1]
A wide range of exploration tools are available for geothermal prospecting, previous exploration strategies within Nigeria have been largely centred on field measurements and geophysical data interpretations[10,11,12]

Summary

Introduction

The development of predictive maps for geothermal resources is fundamental for its exploration across Nigeria. Evidence from spatial and predictive analysis suggests geological data integration is highly efficient for geothermal exploration across the middle Benue trough. The Awgu formation is which overlays the Eze Aku formation is considered to represent an abrupt termination of marine sedimentation within the mid Benue t rough[28]. The Lafia formation is generally considered the youngest sedimentary deposits within the Mid Nigerian Benue trough[29], and is defined by the presence of poorly consolidated ferruginous sandstones (which are often cross bedded) in association with flaggy mudstones and clay containing paleosol horizon[19]. The thickness of the Lafia formation hardly exceeds 50 m, estimated thickness of 500 – 1500 m have been proposed by Offodile and R eyment[22]

Methods

Results

Conclusion