SOLUBILITY OF COMMON OIL FIELD SCALES OF INJECTION WATER AND HIGH-BARIUM CONCENTRATION AND HIGH-SALINITY FORMATION WATER

Scale deposition is one of the most important and serious problems which water injection systems are generally engaged in. Scale sometimes limits or blocks oil and gas production by plugging the oil-producing formation matrix or fractures and the perforated intervals. This paper presents a summary of the laboratory measurements of the solubility of common oil field scales in synthetic brines (formation water and sea water) of high-barium and high-salinity formation waters at 40 to 90 degrees C and atmospheric pressure. The experimental results confirm the general trend in solubility dependencies for common oil field scales at these conditions. At higher temperatures the deposition of CaCO3, CaSO4 and SrSO4 scale increases and the deposition of BaSO4 scale decreases since the solubilities of CaCO3, CaSO4 and SrSO4 scales decreases and the solubility of BaSO4 increases with increasing temperature.