Applications of well logging techniques to evaluate the groundwater aquifers in the area between southwest Bani Sweif and west Asyoute governorate, upper Egypt
Since, the demand on water is increasing; the importance of identifying aquifer characterization and aquifer potentialities is increased with application of well logging techniques. 15 geophysical well logs are used in this study particularly nuclear logs to achieve the main target which is estimating the petrophysical properties and evaluating the formation of Apollonia (Eocene fractured limestone aquifer), Upper and Lower Bahariya (Nubian sandstone aquifer) formations. The results clarify that Eocene fractured limestone aquifer has a carbonate in soft chalk with high permeability, high porosity, while Lower Bahariya formation (Nubian sandstone aquifer) mainly consists of fine to medium grained sandstone and clay which may indicate that it is formed in shallow marine environments of low permeability. On the other hand, Upper Bahariya was recorded as poor sand succession. Permeability of the studied wells recorded the maximum estimated value 2609.69 mdarcy at well ST-258 and the minimum value 1486.812 darcy at well ST-38. The hydraulic conductivity of the two aquifers has a maximum value 4974.39 mdarcy at well ST-188, and the minimum one 1335.97 mdarcy at well WBS1. The estimated Shale volume reached the maximum percentage 31.7% at WBS1 well and the minimum percentage 5.96% at well ST-48, and this means that percentage is used as porosity and permeability in assess the quality of the aquifer which decreases in the west south direction and increases in south and southeast directions of study area. Eocene fractured limestone aquifer in most water wells is classified as highly productive aquifer where it recorded an average transmissivity value of 2285 m2/day and average specific capacity value of 208 m3/h/m. In this aquifer, the water salinity ranges between 2048 mg/l and 2707 mg/l. The resulting physical parameters can help in making decisions to save and protect groundwater aquifers in the future.