Successful matrix stimulation and wax cleaning of a high water cut oil well of east Potwar region: A case study

Effective acid diversion across high permeable and fractured carbonate reservoirs has always been challenging and even more complicated when stimulating high water cut wells. In these types of wells, it is a challenge to stimulate the oil-bearing zones rather than the water-bearing zone. In the case study discussed in this paper, a polymer-free diverter (non-damaging and diverting acid system) was used to divert and effectively stimulate the target formation. The target formation had been produced at a high water cut, which was highly sensitive to the pressure drawdown applied at the formation face. The prime objective of the treatment was to reduce the formation-face drawdown. The acid treatment of 15% HCl with a polymer-free diverter system was used for efficient and well-controlled matrix stimulation. The system consisted of a self-diverter, which forms a gel as acid is spent and temporarily blocks the pore throat, allowing diversion of the main acid for efficient wax cleaning. Well tests were performed before and after the stimulation treatment. Well test results indicated an increase of ~ 160 bbl/day in oil production with a decrease of water cut to zero from ~ 37%. The increase in oil production and elimination of water cuts shows the success of the stimulation treatment.