The Largest Acid Stimulation in a Dual Lateral Power Water Injector in Saudi Aramco

Abstract

Abstract This paper will discuss the largest coiled tubing acid stimulation operation completed on a water injection well in Saudi Arabia. Stimulation design, field execution and the well performance before and after the treatment as well as massive planning, logistics and coordination are the key elements of this discussion. Furthermore, the authors would like to briefly review the future plans for other long/ multilateral wells in the area. This job was conducted on a dual lateral horizontal power water injector. The objective of this job was to stimulate the formation of both laterals by pumping 20% hydrochloric acid (HCL) and 20% strength diesel-emulsified acid and diverting it with 20% viscoelastic surfactant based acid on using Coiled Tubing (CT) and a Multilateral Tool (MLT). A total of 10,335 ft horizontal interval was successfully stimulated with 362,700 gallons of treatment fluid in 27 stages using 2 3/8" CT. On this job the MLT was successful in locating each lateral. The post-acid injection rate has been increased by more than double, higher than initial expectations. Consequently, the injectivity index has been increased drastically above the field average. Based on success of this stimulation job, the concept of designing and treating other Maximum Reservoir Contact (MRC) injectors using this technique becomes a recommended intervention process. The key to enhance future jobs lies on the ability to effectively capture and use the lessons learned from this massive operation. The continuous success of these jobs will help to improve the water injection system in Ghawar field and will enhance oil recovery.