Geological and geochemical evaluation for lower Kuwait group and Dammam Formation aquifers in UMM-Gudair, Shigaya, Sulaibiyah and Atraf Fields, Kuwait

This study investigates the effects of geological structure of the aquifers and the chemistry of water by testing the water chemistry variation such as the main cations (Na+, K+, Ca2+, Mg2+) and anions (Cl-, SO42-, HCO3-) and TDS from west of Kuwait in Umm-Gudair field toward the east part of the country in Sulaibiyah and Atraf fields and crossing the Shigaya field in the middle part of Kuwait.;Stable oxygen and hydrogen isotope composition of groundwater were compared with the Kuwait local meteoric water line to examine if there were any interaction between aquifer groundwater and the recent rainfall events in the region of study. Based on the structure of the area of study and the chemistry analysis, variation maps were created to show the spatial distribution of changing water chemistry concentrations in the different structural elements of the study area. A numerical groundwater flowing model was established to better understand the groundwater flowing pattern and velocity while crossing different geological structures such as anticlines and synclines.;Stable oxygen and hydrogen isotope composition of groundwater for Kuwait shows that the aquifer groundwater is effected by evaporation process. The slope and distribution of the Bahrain isotopic ratios show that the groundwater in the area of study does not came from the meteoric water or the rainfall events in the region. Instead the groundwater in the aquifer system is recharged from far distance source area or the groundwater is very old.;Studying the structure of the area and the chemistry analysis variation shows consistant chemical concentration increases in the southeastern direction towards the Ahmadi Arc. The first possible reason behind this change is the long distance and hence water/rock interaction increase. The other reason is Ahmadi arc traps groundwater and with time the rock and water interaction will increase. Faults and fractures in the highly deformed Ahmadi Arc can act as a passage to other fluids moving from deeper to the shallower aquifers.;In the Shigaya-B water field, all chemical concentration in groundwater showed decreases except the HCO3- increase. This thesis proposes that high production rate, deformation of aquifers and mixing of aquifers groundwater in Shigaya B field are reasons behind the relative slowdown of Groundwater in Dammam Formation and this mixing and slowing of groundwater is responsible for relative reduction of most chemicals concentration such as TDS, Ca+2, Na+, K+, Mg +2 and Cl-, it is also responsible for HCO3 - relative growing in concentration.;The model predicts that in Dammam aquifer at both 1985 and 1995 the groundwater velocity relatively slowing down while crossing Shigaya B anticline crest. Reasons behind this velocity change are the higher rate of production and the tensile fractures in the anticline crest which can act as a window to let groundwater vertically moves from shallower aquifers to deeper ones and vice versa.