ANALISA TERBENTUKNYA SCALE DENGAN MENGGUNAKAN METODE STIFF AND DAVIS PADA SUMUR BEL-X DI LAPANGAN LIMAU

Abstract

The BEL-X well is one of the older wells in the Limau field. A common problem with wells in this field is the formation of scale deposits. Scale is a precipitate formed due to the process of crystallization and deposition of minerals contained in the formation water. Scale formation occurs due to pressure drops, temperature changes, pH influences, and the mixing of two incompatible types of water so that the solubility limit of the compounds contained in the formation water is exceeded and it reacts to form solids. The formation of scale can cause a decrease in production at the BEL-X well due to obstruction of flow in the tubing and flowline as well as other production equipment, which results in damaged production equipment. The purpose of this research is to determine the trend of scale formation in the BEL-X well using the Stiff and Davis method by calculating the Scaling Index (SI) values at various testing temperatures (25º C, 60º C, and 100º C). After doing the calculations, the Scaling Index (SI) value at 25º C is +0.487, the Scaling Index (SI) at 60º C is +1.327, and the Scaling Index (SI) at 100º C is +2.627. Based on these results, a positive (+) SI value was obtained, which meant that there was an indication of the formation of Calcium Carbonate (CaCO3) scale in the BEL-X well. After the scale is identified, efforts are needed to deal with the scale problem, both in the form of preventive steps and countermeasures when scale has occurred in the well. To deal with the scale problem that occurred at the BEL-X well in the limau field, the lining tubing affected by scale was replaced with new equipment, and chemical scale inhibitors were used, including solid scale inhibitors in the form of Calgon and liquid scale inhibitors in the form of phosponate. In addition, to determine the scale growth rate in the BEL-X well, a scale coupon was installed to determine the thickness of the scale so that scale problems could be prevented in the future.