Scale Squeeze Implementation for an ASP Flood

Abstract

This study is about scale squeeze application for ASP pilot that was carried at Marmul field. This is first kind of scale squeeze treatment for ASP application. High pH associated with the ASP slug injection and production (pH>10.5) provides a rich environment for scale precipitation of metal ions when mixed with injection water. (1) Multiple activities associated with the scale squeeze treatment (evaluation, screening, modeling and application) were carried out from 2008 – 2016 in-house as well as with different vendors. It was quite challenging to find suitable scale inhibitor which is capable for scale inhibition at elevated pH and has longer squeeze life time. The squeeze application was designed to start with a pre-flush stage to displace tubing fluids, acts as a spacer, condition the formation near the well bore and prevent water blocks/emulsions, followed by a main flush stage that has the highest concentration of SI in the mixed brine. Later on, a post flush stage was injected to displace the main flush further into the reservoir and increase adsorption. Finally, tubing displacement is injected which was about 5 m3 for each well. The scale squeeze treatment for the four MM ASP production wells was completed prior to the ASP slug injection. A shut-in period for each well was applied to ensure adsorption of the chemical to the reservoir rock. Monitoring of the scale inhibitor return profile after the squeeze treatment for each well was carried out to determine the flow back characteristics and to evaluate the efficiency of the treatment. The monitoring evaluation has indicated that the scale squeeze treatment was successful in inhibiting the formation of scale in all of the four production wells and the concentration of the scale inhibitor was above MIC of 10 ppm. The scale inhibitor return profile concentration was also found to be in a very good alignment with the theoretical model and the treatment efficiency is passing the six months treatment life time period. This was successful implementation and proved the concept of appropriate propagation of SI from the formation to production system.