Acid Stimulation Results of Arab Carbonate Reservoirs in Offshore Field, U.A.E.: 10 Years of Review, How to Prepare the Future Challenges Linked to Stimulation

Abstract

Abstract The Upper Jurassic Arab Formation in Offshore Abu Dhabi represent a regressive cycles of sedimentation developed with shoal, laggonal, subtidal and supratidal sediments. This formation includes various types of lithologies along the reservoir column: Anhydrite alternating with Dolomites, limestone of grainstones and mudstones/wackestones. Matrix Acid stimulation treatments are routinely performed using HCl and it is playing a vital role in developing oil carbonate reservoirs. As around 60% of the oil reservoirs in the world are carbonate with high heterogeneity: improving stimulation techniques/technology is a major challenge to enhance oil recovery and overcome the heterogeneity in such reservoirs. Stimulation operation results are affected by reservoir heterogeneity. Understanding formation texture in carbonate greatly affects the success of stimulation jobs. Many factors can affect the results of an acid job such as chemicals (acid), mineralogy of the rocks, and the permeability variation through the formation. Proper Acid placement and zonal coverage are some of the most important factors for successful matrix acid stimulation treatments. A giant field on production for 40 years is the focus of 10 years of acid job investigations. We evaluated the effect of the acid and identified the main parameters that control its efficiency and maximized well productivity (acid techniques, placement methodology, etc.). This paper will detail the analysis done in 100 wells and the results will show the best techniques deduced from these 10 years of experience. This study aims to improve acid techniques/technology to maximize well productivity, in all reservoirs types and consequently improve oil recovery.