oa Evaluation of Acid Stimulation Performance in Oil Wells in Qatar Using Skin Characterization

Acid stimulation is widely used in carbonate reservoirs to stimulate wells and enhance productivity. Almost every well in Qatar undergoes acid stimulation before production starts. The main purpose is to remove any damage in the near well-bore region from drilling fluids. Successful stimulation jobs result in a skin factor between -4 and -6.

During acid injection, the value of injection rate and pressure is recorded. Real-time monitoring of this data can be very helpful in evaluating the performance of the stimulation process and in guiding its progress. In some cases, wells can be over stimulated resulting in damage to well productivity. In other cases, the volumes injected might not be enough to establish proper displacement of the acid into the formation.

As a part of the research collaboration efforts between Texas A&M University and Total Research Center at Qatar, a software that was developed by the research team in the College Station campus was used to analyze the performance of three acid stimulation jobs that were conducted in Qatar. Records of the stimulation data were collected and the skin was analyzed. The performance of the software was evaluated by comparing its predictions to the actual performance of the well. The results show that skin characterization during acid injection is capable of predicting well performance and in some cases it can be used to ensure the success of the acid stimulation job.