Abstract

Burkina Faso, like the other countries of the Sahel, suffers from a lack of surface water because of geographical, geological and climatic conditions. This means that the country is often obliged to make use of subsurface water to supply small towns, villages and the countryside with potable water. However the success rate of drilling campaigns is quite low (70 percent for wells with a flow from 0.5 to 5 cubic metres per hour; 15 percent for wells with a flow of more than 5 cubic metres per hour). Subsurface water is encountered in fractures with a limited surface area. To obtain a high rate of flow, drilling must be precise in its location. This project will define the geological conditions which determine different rates of flow (particularly rates of more than 5 cubic metres per hour), so as to increase the success rate in drilling campaigns. A comparative approach will be adopted which will make use of the electromagnetic method with a mobile source. Project participants will attempt a preliminary evaluation of the possibility of using artificial stimulation by hydraulic fracturing of unproductive drillings.

Post-Project Summary

The studies focused on 11 wells yielding more than 20 m cu/h, each one associated with a dry well or a well yielding less than 2 m cu/h in the same type of geological environment. The sites were studied using remote sensing, geological assessments, geophysical prospecting reports and chemistry. The results they obtained represented the main factors that had to be considered in order to obtain satisfactory results from well drilling projects. The methodology developed during the project was checked out during a project involving 78 drilling sites at school gardens in the provinces of Yatenga and Passore. The methodology made it possible to increase the success rate from the usual average rate of 65% to more than 90%. A second phase project was approved to verify the methodology at high yield drilling sites and to adapt it as necessary. The Burkinese researchers ran a training program for field officers who are in charge of setting up drilling sites and doing follow up in Burkina Faso, Mali, Niger and Tchad.

Recipient Institution(s)