Investigation of Optimum Effect of Matrix Acidizing in Carbonate Reservoirs Stimulation of Darian's Formation of Ahwaz Oilfield

Due to the failure of some stimulation operations which have applied on carbonate reservoirs of Darian’s formation of Ahwaz oilfield, in order to improvement in formation damage and increase in permeability, the effect of several acids (HCL with 10%, 15% and 28% dosages) was evaluated by comprehensive research on a candidate well. Moreover, the porosity type of this formation was evaluated due to another research by using core analysis tests, FMI Tool reports and well testing analysis by PanSystem v3,4 software. According to the results, high concentration of acid, it is not always in tune with its increasing performance and the optimum concentration on the conditions of each reservoir and oil wells should be consider. Consequently, using HCL 15% is creating the best condition to this stimulation process. Success of this operation is also clear due to decreasing in skin factor of 5 to -4.45. Since there is a disagreement between the reservoir engineers regards to the being single or dual porosity of Darian’s formation, notwithstanding of its carbonate reservoirs, being single porosity of this formation is more logical, according to the evaluation’s results.