Perpustakaan Digital ITB

Matrix acidizing is one of the most widely applied stimulation techniques for restoring near-wellbore permeability and improving hydrocarbon production. However, field applications do not always produce the expected production improvement, particularly when hydrofluoric acid (HF)-based mud acid interacts with complex reservoir mineralogy. This study evaluates the performance of matrix acidizing treatments in three gas wells within the BWA Field using production performance analysis and investigates the mechanisms responsible for unsuccessful stimulation. The evaluation was conducted by developing pre-acidizing and post-acidizing Inflow Performance Relationship (IPR) models using the Jones gas deliverability equation. The models were matched through history matching to estimate changes in permeability, skin factor, and Absolute Open Flow (AOF) before and after stimulation. The production responses obtained from Wells BWA-2, BWA-3, and BWA-4 were subsequently compared to assess the performance of mud acid and hydrochloric acid (HCl) treatments. The observed production behaviour was then interpreted using established acid-rock interaction theories and mud acid reaction mechanisms. The results indicate that matrix acidizing using 20% HCl successfully improved well productivity by reducing skin factor, increasing permeability, and enhancing gas deliverability. In contrast, the mud acid treatment applied in Well BWA-2 resulted in severe production impairment despite exhibiting the highest laboratory solubility. The deterioration in productivity is interpreted to be associated with secondary and tertiary precipitation reactions during mud acid spending, which generated insoluble reaction products that reduced near-wellbore permeability. This study also demonstrates that conventional laboratory solubility tests are unable to fully represent the complex chemical reactions and reservoir conditions encountered during field applications. The findings emphasize that successful matrix acidizing depends not only on laboratory dissolution performance but also on reservoir mineralogy, acid reaction mechanisms, and field operating conditions. Therefore, acid selection should integrate laboratory evaluation with reservoir-specific characteristics and acid-rock interaction analysis to minimize stimulation failure and optimize production performance.