| Six formation water samples were collected from six wells sunk in Yamama reservoir formation water in west Qurna oil field . temperature , PH, and electrical resistivity were directly measured on the spot . Then the collected samples were analysed for Na+ , K+ , Ca+2 , Mg+2 , Fe total H2S Cl- , CO3-2 , HCO3 , SO4-2 , and total dissolved Salt (T.D.S) . The formation waters under study are characterized by their acidic medium (pH=5.88) and thermal nature (97-115◦C) and low resistivity . The Hydrogeochemical study suggests that the Yamama formation waters be of Na-Ca-Chloride type . This type of water reflects the marine origin and subjection to diagenesis prosesses , further more , the hudrochemical ratios indicate the expected west ward flow of Yamama formation water in west Qurna field , beside , the relative stagnant conditions favorable for hydrocarbon preservation . |