Successful Reserve Unlocking: Acid Pumping Revives ESP Well in the Yakin Field, East Kalimantan, Indonesia

Abstract The Yakin Field, situated in the southern region of East Kalimantan, Indonesia, features sandstone reservoirs and was discovered in April 1976, with production commencing shortly thereafter. Currently, the field consists of 128 active wells, 55 wells operating with ESP. Well X represents a new addition to the Yakin Field, designed to produce an estimated 100 barrels of oil per day (BOPD) from unconsolidated sand reservoirs. Drilled and completed with sand control screens and Electric Submersible Pumps (ESP) for artificial lift, Well X commenced production in July 2023. However, the well initially exhibited only intermittent flow, attributed to a suspected positive skin near the wellbore (NWB) caused by ineffective removal of drilling mud cake. Laboratory tests were performed on the mud cake sample to determine the most effective breaker for NWB skin and improving well productivity. After thorough evaluation, Aromatic Solvent Acid Dispersion (ASAD) emerged as the preferred treatment, complemented by a fluid diverter treatment to ensure proper distribution across the perforation interval. This was followed by displacement with a 3% KCL Brine solution. ASAD is deemed compatible with the mud cake, as its solvent dispersant effectively breaks down the base fluid of the mud and inhibits wax or sludge from the hydrocarbon fluid, while the acid dissolves the particulates present in the mud cake sample. The operation proceeded smoothly, with a pumping rate of 0.5 barrels per minute (bpm) for fluid coverage up to 3 ft beyond the perforations as per the program. During the main acid pumping phase, a notable decrease in pumping pressure was observed upon initial contact between the acid and the mud cake, indicating a favorable reaction. Upon completion of the treatment, the well was returned to production and now exhibits stable oil flow. The results were significant, with cumulative oil production in the two months prior to treatment with total approximately 2,400 barrels, compared to around 4,000 barrels in the two months following the treatment. This notable increase in production underscores the success of the treatment in improving well productivity and enhancing oil recovery from Well X in the Yakin Field.