Field Application and Performance Evaluation of a Cost-Effective Matrix Acidizing Technique in Naturally Fractured Carbonates - Case Studies from Gulf of Suez

Abstract

Abstract Improving production in offshore brownfields presents significant challenges, particularly in extracting additional oil from layers unaffected by water breakthroughs, especially in commingled completions. Conventional matrix stimulation treatments in commingled completions often require straddle packers to achieve effective zonal coverage and selective treatment. However, the complexity escalates when mechanical isolation methods are more expensive than chemical diverters. This research paper introduces a comprehensive approach encompassing several vital factors to enhance production in these challenging scenarios. The approach includes understanding the inflow productivity of wells, addressing water breakthrough and low specific productivity index in commingled layers, formulating appropriate acid chemical recipes, selecting suitable chemical diversion methods, identifying optimal well candidates, and optimizing job execution to improve success rates. To illustrate the application of this approach, three candidates from the Gulf of Suez basin, a complex and heterogeneous basin located in the Eastern Desert of Egypt, produced from carbonate reservoirs, are examined as case studies. Extensive laboratory tests were conducted to develop a chemical diversion technique that simultaneously serves as a water conformance agent and a diverter. A viscous pill was prepared to temporarily isolate fractures or fissure networks while diverting the treatment away from water zones before proceeding with the complete acid treatment. The results of this innovative diversion technique demonstrate a significant four-fold increase in well productivity while reducing water cuts. This paper presents our approach and showcases the laboratory test results of this unique recipe and cost-effective diversion technique designed explicitly for fractured and watered-out carbonate reservoirs. Additionally, it highlights the valuable lessons learned while applying these methods, offering insights and practical knowledge for future similar projects.