Acid Treatment Challenges and Solutions in Sandstone Formation with Various Formation Damages

Summary This paper presents a systematic approach to design acid treatment for a well that was successfully completed into a sandstone formation initially had a high production rate of nearly 5,000 barrels of oil per day for approximately 50 days, then experienced a sharp decline to less than 1,000 barrels of liquid per day, at the same time as the water cut increased. A thorough investigation was performed to identify the damage mechanisms, followed by matrix acid stimulation, to enhance productivity. Following the initial acid treatment aimed at removing downhole scale, the well productivity index increased from 0.2 stbpd/psi to 0.4 stbpd/psi. A further treatment targeting the removal of fines migration resulted in a stable productivity of 0.7 stbpd/psi one month after the acid treatment, and the well is currently producing at approximately 3.2 stbpd/psi, close to its initial productivity before the sharp decline. This case study can serve as a reference for other acid treatments aimed for sandstone formation under similar conditions.