Integration of resistivity, neutron, and density logs for detecting, identifying, and calculating of groundwater over-pressuring phenomenon at Siwa Oasis Depression, Egypt

Abstract Along with Siwa Oasis depression, there are several ponds, lakes, and Sabkhas features resulted from the current flows through springs due to over-pressure of deep sandstone aquifer. The Nubia Sandstone aquifer (NSA) Carbonate main two water-bearing units. They separated by a huge thickness shale controlled complicated structural faults. There ten wells including gamma-ray, short long resistivity, caliper, neutron, density logs. These logs were used in identifying lithology, calculating porosities, water saturation percentages, effective permeability. detect, identify, calculate this its zones. porosity, formation determining expected normal compaction trend. top over-pressuring, over-pressuring forewarning, transition, zones detected. pressure gradient calculated at first depth zone. piezometric heads pressures mapped. depths over-pressures, pressures, their maps constructed. statistical analyses between carried out. Accordingly, type shale, aquifer, overlaid conditions considered factors generating phenomenon Oasis. Therefore, study considers that compatible powerful tools studying phenomenon.