Well geophysics in the exploration of groundwater resources: A case study

Investigation of groundwater resources by geophysical methods is of great importance today due to its economic and easy methods. In this study, self potential, resistivity and gamma ray log values obtained from wells and sediment samples were compared and evaluated for the effective investigation of groundwater resources. In general, these methods are directly related to the identification, investigation and economic supply of aquifer zones. The well log data obtained allows the determination of parameters such as the presence of water, water yield, static and dynamic levels of the well, and well depth. The aim of groundwater investigation is to determine the formations encountered in the drilled boreholes and to evaluate and record their physical properties (radioactivity, resistivity, layer thickness, temperature, porosity). In this study, 5 boreholes drilled by DSİ 18th Regional Directorate for water research in Isparta, Afyonkarahisar and Burdur provinces and districts were evaluated. The parameters to be considered during the application of well log measurements were analysed. The data obtained from the wells were evaluated and features such as layer boundaries, thickness, depth, lithological character, porous and permeable layers, layer boundaries, separation of clayey levels were interpreted and tried to be revealed. As a result of this thesis study, the importance of placing a filter in the correct lithology was revealed with the SP, resistivity and gamma ray log measurements taken from the well. Incorrectly constructed wells can cause the filter pipe to be placed in clay layers, which can lead to collapse of the clay units in the well and unwanted fills. Therefore, well geophysics is a method that should be used in groundwater exploration.