Effective Perforating Design for Matrix Acidizing in Pre-Salt Carbonates

Abstract

Engineers face many challenges in deciding how to complete Pre-Salt, carbonate reservoirs offshore Brazil. These challenges include: predicting reservoir performance; evaluating well productivity; determining the best completion design strategy; and finally, determining the best matrix stimulation techniques. Matrix acidizing is a common approach to enhance production from carbonate reservoirs. Well defined wormholes bypass near wellbore damage and provide greater reservoir productivity. Poorly known microbial carbonate can impact acidizing diversion and effectiveness in such rock. Optimizing the stimulation process by perforating and acidizing in the correct way in such high-cost projects is a crucial issue for improved well productivity. This paper discusses how effective perforation design positively impacted the evaluation (Well Testing) and acidizing efficiency in such formations. Results from pre and post matrix acidizing PLT logs and transient analysis from downhole and surface well test data demonstrates perforating design efficiency and how it aides in diverting acid over the entire interval compared to another well in the same field.