Abstarct: Gas and petroleum production in petroleum fields can be accompanied by brine production. with its huge hydrocarbon resources,Iran has a great potential of economic exploitation to produce brines. There is a hope to use the brines in near future because of advancement of technology.To survey and evaluate the potential of valuable mineral elements in brines produced from oil wells, to determine the probable origin of brines, and the salinity of water produced by oil wells in Full of oil areas of the south, Ahvaz, Aghajari, Maroon, Masjed Soleiman, Lali and Zeilai oil fields were chosen.10 samples of produced saline water have been extracted from the mentioned oil fields. In this study, Advanced Instrumental analysis methods such as induced coupling-optical emission plasma spectroscopy (ICP-OES), ion exchange spectrometry and Leipzro's spectroscopy Arrangements for measuring major, minor, and trace elements, fluorine anions, chlorine, bromine and iodine, total soluble solids (TDS), acidity (pH), electrical conductivity (EC), sulfate anions (SO42-) and bicarbonate (HCO3-), as well as determination of isotopic oxygen and deuterium ratios ,were used to evaluate feasibility study of valuable mineral elements and determine the salinity source of water produced by oil reservoirs, saline water samples. The EC value varies from a minimum of 9785 µS /cm in Maroon oil field (MN2-07) to a maximum of 324554 µS /cm in Ahvaz oil field (AZ3-03) with an average of 201621 µS / cm. The values of TDS concentration in the brackets of the studied oil fields in Dezful depression fall from minimum 6360 mg /l in Maroon field (MN2-07) to maximum 210960 mg/l in Ahvaz field (AZ3-03) and their average is 131054 mg /l. The average amount of TDS in the studied oil brines is very similar to some of the oil brines in the world. The primary source of brine can be evaporated Old Sea or present-day seawater, salt dissolution, or atmospheric water. The primary origin of the brines produced from the studied reservoirs was most likely the old sea water evaporated in lagoon environments. The water type of the studied samples is from chloride-sodium to chloride-sodium-calcium. The concentration of elemental brine produced by reservoirs can also vary over time due to evaporation and the water-rock reaction. The elements Li, Sr, Br and I, which are very important for the extraction of oil brines, these elements, especially I in the studied samples are less concentrated in the studied samples compared to the brines produced from the world's oil fields. However, the concentration of Br, Li, Sr and other major elements in the saline waters produced by the studied oil fields are high compared to seawater, in case of construction of extraction units and extraction of important mineral elements from oil brines, in addition to part It is supplied from the water required by the industrial units of the nearby areas. It is possible to provide an important part of the maintenance and use costs by extracting and selling the mineral products obtained from these units.