Université Félix Houphouët-Boigny d'Abidjan-Cocody, Unité de Formation et de Recherche des Sciences de la Terre et des Ressources Minières (UFR-STRM), Laboratoire des Sciences et Techniques de l'Eau et de l'Environnement (LSTEE), 22 Bp: 582 Abidjan 22, Côte d'Ivoire
The objective of this study is to develop statistical models to predict the drilling flow on rock aquifers. The study area is the former region of N'zi-Comoé (Central-East of Ivory Coast) that is located between longitude 3° 40' and 4°55' West and latitude 6° 20' and 8°10' North. The geological formations are composed of igneous rocks and metamorphic rocks. The methodology has been first applied to the approach of principal component analysis normalized, for identifying relevant and expressive variables of the drilling flow. Then, a calibration was performed with a sample of 100 drillings representing two thirds of the total sample to determine the coefficients of linear regressions and associated standard errors. Finally, an evaluation of the developed models was performed using the criteria of performance and robustness. The most relevant and expressive variables for modeling the drilling flow are the transmissivity, the thickness of healthy base drilled, the depth of the first significant water inlet and the total number of water inlet. Thus, two models were developed. Models assessment shows that they are performing with correlation coefficients ranging around 0.7, biases varying between 10-7 and 10-2 and quadratic errors in the order of 2.5 to 2.9. These models have also demonstrated their robustness with rates fluctuating between 3.2 and 5.3%. However, the model 2 is more efficient and more robust than model 1.