PREDICTION OF CALCIUM CARBONATE AND CALCUIM SULFATE SCALE DEPOSITS IN MABRUK OIL FIELD, LIBYA

Abstract

This Study focuses on predictions and probability of calcium carbonate and calcium sulfate scale formation. It has been conducted in the Sirt Basin on concession ‘‘NC -17’’ namely is Mabruke oil – field. Twenty-six chemically analysed water samples from different wells in this oil field were used in this study; these samples showed Total Dissolved Solids (TDS) ranges from 9075 to 85261 mg/L. The chemical analysis of petroleum – associated waters from such wells was studied and interpreted. This was done in order to find out and predict CaCO3 and CaSO4 scales. This prediction was based on geochemical analytical calculations as well as applying Stiff and Davis method, this method is one of the easiest ways to calculate calcium carbonate and calcium sulfate scaling in brines, Where the saturation index is calculated and thus the prediction of scaling deposits. Accordingly, it was found that CaCO3 scale was found to be likely in most water samples, Factors causing this type of scale are mainly pH, Pressure, HCO3 and Ca concentrations. On the contrary CaSO4 scale was found unlikely in most of the studied waters, with the fact that salinity, Ca+2 and SO4-2 concentrations are the main factors causing such scale.