Comparison of Some Physical and Chemical Properties of Associated Water and Crude Oil in Sharara and Irawan Fields, Murzuq Basin, Libya

Abstract

The study concluded that (pH) in all water samples in the Erawan and Sharara fields was within the specified standards (6-9), and the values ​​of (TDS)concentration varied between (147-319mg/L),(Cl^-1) between (535-537 mg/L), and (SO₄^-2) between (141-187 mg/L), and the values ​​of (S^-2) between (0.139-0.198 mg/L) in the Erawan field, which are within the permissible limits. In the Sharara field (TDS) varied between (1149-1155 mg/L), (Cl^-1) between (1416-1420 mg/L), and (SO₄^-2) between (4229-4232 mg/L), and all of them exceeded the permissible limits, and the values ​​of (S^-2) varied between (0.539 - 0.639 mg/L) which is within the permissible limits, and the cations except potassium did not exceed the permissible limits in all samples and (K) is within the permissible limits in the samples of the Erawan field, and ranges from critical limits to exceeding the permissible limits in the samples of the Sharara field, and the quality of the associated water studied in this study was classified as type (CaCl₂), which is the closed deep construction environment, and this type reflects a good closed condition in which oil and gas can be easily collected and stored. As for the results of the oil samples, it was found that the Erawan field crude is classified as very light oil and the Sharara is light oil (41.06 , 38.90) respectively according to the American Petroleum Institute (API°) degree, and the Erawan crude is less dense than the Sharara crude and the water percentage (0), and the Sharara crude is 19.75% and the NaCl percentage (9.27×10-3% - 2.92×10-1%) in the Erawan and Sharara crude respectively, and the Erawan crude is of higher quality than the Sharara crude and the associated water in the field Iraun is a higher quality companion to the spark field that has exceeded the permissible limits in some indicators.