Investigation of barium sulfate deposition by capillary flow and thermal effect on silica precipitation in acidic solution

Abstract

In the oil industry, scale composed of barium sulfate (BaSO₄) is one of the most troublesome and expensive problems found in the oil production process due to its relative low solubility compared with other typical scale minerals. This research is focused on developing a technique for investigating barium sulfate deposition - in particular. Capillary technique has been developed as a potential technique for scale deposition experiments. Subsequently, this technique is used to investigate the deposition mechanism by the change in pressure drop. Moreover, the mass of the deposit formed was determined by dissolution with DTPA (Diethylenetrinitrilopenta acetic acid) which effectively dissolve and form complex with barium ions. The results show that the deposit is non-uniform and preferentially located near the beginning of the capillary. Another major problem mainly found in the oil industry is silica precipitation during matrix acidization. This research has observed the influence of thermal effect on silica precipitation in acidic circumstance at 50°C. The results show that the silica particle growth at high temperature is greater than that at low temperature (5 °C) From UV-Vis experiments, it was found that the monosilicic acid The activation energy of monosilicic acid disappearance was determined and found to be 7.2 kcal/mole.