Acid Stimulation with Tailored, Not Cookie-Cutter Solutions in a Field with High Reservoir Heterogeneity

Abstract When early production results from a recent major infill drilling project in a Southern Oman field revealed that a significant number of wells were underperforming, analysis identified drilling-induced formation damage and increased reservoir heterogeneity in certain blocks as the main culprits. To address these challenges and enhance productivity, a cost-effective stimulation strategy was developed where acid recipes would be tailored based on results from small-scale acid bullheading campaigns. This paper illustrates the advantages of this customized acid stimulation strategy over conventional "cookie-cutter" approaches. Five campaigns were conducted, and treatments progressed from a standard, fixed volume 10% HCl acid job to increased acid volumes and concentrations linked to well lengths and dominant facies. The addition of mutual solvents helped manage emulsion issues in some parts of the field. The most effective recipe was then pumped in over 40 wells. A final campaign was conducted for selected flank area wells, mostly penetrating poor-quality reservoirs. Overall, this strategy delivered significant production gains. Initial treatments resulted in a ∼50% gross increase which improved to 70% gross increase when pumped acid volume was increased. Higher acid concentration and mutual solvent achieved a 300% gross increment, though emulsion issues arose in some wells. Scaling up the tailored approach achieved 400% gross increment, finally exceeding the forecasted oil rates. Wells with the poorest reservoir quality required a change in acid type to mud acid and resulted in a 30% gross increment. The results highlight the importance of adapting acid type, volume, and additives to specific well and reservoir conditions. The tailored approach not only outperformed standard treatments but also demonstrated the necessity of ongoing adaptation for maximum productivity and operational efficiency. This adaptive, data-driven approach maximizes production gains and addresses unique challenges in each area of the field. In addition, it shows a novel approach of stimulation through standalone units without pulling out the pump and with limited oil deferment and hoist cost avoidance.