A Successful Acid Fracturing Treatment in Asphaltene Problematic Reservoir, Burgan Oilfield Kuwait

Abstract

The Burgan Marrat Reservoir is a challenging high-pressure, high-temperature carbonate oil reservoir dating back to the Jurassic age. This specific reservoir within the Burgan Field yields light oil, but it has a significant issue with Asphaltene deposition in the wellbore. Additionally, its well productivity is hampered by low matrix permeability. Addressing these challenges is crucial, and a successful acid fracturing process can not only enhance well productivity but also address Asphaltene-related problems. This study delves into a comprehensive methodology that was employed. The focus of well selection was on ensuring good well integrity and maintaining a considerable distance from the oil-water contact (OWC). The approach involved conducting a Multi-Rate test followed by pressure build-up to establish a baseline for understanding the reservoir's behavior, including darcy and non-darcy skin. The treatment design aimed at better fluid loss control and initiating highly conductive fractures in the reservoir. Specific measures, such as using suitable diverters and acid, were employed to maximize the length of the fractures. To validate the approach, a nodal analysis model was fine-tuned to predict how the well would perform under these conditions. The results post-stimulation were impressive. There was a substantial improvement in well production and flowing bottom hole pressure. In fact, the productivity index of the well increased significantly, representing a substantial enhancement in output. The pressure build-up test after the fracture demonstrated a linear flow within the fracture, indicating a successful treatment with a fracture half-length of approximately 110 feet and a negative skin, which signifies an improvement in flow efficiency. Furthermore, the treatment effectively mitigated the risk associated with Asphaltene deposition, a significant accomplishment given the historical challenges faced in this reservoir. This success can be attributed to an innovative workflow that incorporated a meticulous surveillance plan, a well-thought-out fracturing treatment design, and the application of advanced nodal analysis. Together, these components not only optimized the well's performance but also paved the way for the development of similar high-pressure, tight carbonate reservoirs. This approach not only enhances productivity but also ensures successful mitigation of Asphaltene-related issues, marking a significant advancement in reservoir engineering techniques.