Improved Stimulation Effectiveness of Water Injectors Using Coiled Tubing with Fluidic Oscillator-——Case Studies from a Major North Kuwait Field

Abstract

Water injectors typically suffer from injectivity decline attributed to near wellbore (NWB) damage typically caused by variation in injected water quality, pores plugging caused by scale precipitation, and fines migration. Conventional stimulation treatments to improve injectivity are conducted with coiled tubing (CT) to enhance fluid placement. However, this often sacrifices stimulation effectiveness because of the relatively low fluid penetration into the formation compared to bullheading treatment. The net result is lower than the expected treatment efficiency and increased stimulation frequency. This paper discusses a new placement technique using a fluidic oscillator (FO) tool that causes alternate bursts of fluids within the wellbore. The resulting pressure pulses propagate radially into the formation, carrying the stimulation fluid and enhancing its penetration deeper into the reservoir. A well- planned stimulation treatment recipe in combination with CT and a FO proved to be very effective in terms of stimulating water injectors. Case histories from six water injector wells stimulated using this technique is presented. Post-stimulation results show considerable increase to injectivity rates and decrease of stimulation frequency.