Perpustakaan Digital ITB

Matrix acidizing is one of the most commonly applied stimulation techniques in carbonate reservoirs. It restores or enhances well productivity in wells experiencing formation damage around the wellbore. Evaluating its effectiveness in wells with a commingled completion scheme requires a more comprehensive approach. Treatment success must be assessed both at the level of each productive interval and at the level of overall well performance as a single production system. This research evaluates the effectiveness of matrix acidizing in two commingled carbonate reservoir wells, namely NUR and OTO, at both the individual interval level and the combined production performance level. Inflow Performance Relationship modeling was used to compare well conditions before and after treatment. Permeability and skin factor for each interval were obtained through a matching process, while pre-treatment conditions were represented through a synthetic baseline approach. Results show that skin factor improved consistently across all acidized intervals, changing from a positive pre-acid condition to a negative post-acid condition. The permeability increase varied from 1.00 to 123.33-fold, while Absolute Open Flow increased up to 1,324.9- fold in the interval with the lowest initial productivity. This pattern is closely related to tight formation characteristics and the acid fluid formulation applied. Permeability enhancement was most limited in a tight formation treated conservatively. It was considerably higher when a more aggressive acid formulation was applied under similar formation conditions. Commingled multilayer modeling produced a total Absolute Open Flow of 5,737.1 STB/day for NUR and 2,509.4 STB/day for OTO, with interference loss relative to the sum of individual layer rates remaining below 3% for both wells. Overall, matrix acidizing provides a significant improvement in flow performance in commingled carbonate reservoirs, with the degree of success varying depending on the condition of each interval. Commingled production remains an advantageous choice, given the small loss due to inter-layer interference compared to the additional production capacity gained.