The state of the art in scale inhibitor squeeze treatment

Abstract

The mechanistic understanding of the reactions that govern the inhibitor retention and release, modeling, and the state-ofthe-art innovation in squeeze treatment are reviewed. The retention and release are governed by (1) the amount of calcite that can dissolve prior to inhibitor-induced surface poisoning; (2) calcite surface poisoning after ~ 20 molecular layers of surface coverage by the adsorbed inhibitors to retard further calcite dissolution; (3) less base, CO 2− 3 , is released into the aqueous solution; (4) formation of the more acidic inhibitor precipitates; (5) phase transformation and maturation of the more acidic inhibitor precipitates; and (6) dissolution of the less soluble crystalline inhibitor precipitates. The trend to advance squeeze technologies is through (1) enhancing scale inhibitor retention, (2) optimizing the delivery of scale inhibitors to the target zone, and (3) improving monitoring methods. Lastly, a prototype yardstick for measuring the squeeze performance is used to compare the squeeze life of 17 actual squeeze treatments. Even though the various squeeze treatments appear to be different, all published squeeze durations can be rated based on the normalized squeeze life per unit mass of inhibitors.

Review of Phosphorus-Based Polymers for Mineral Scale and Corrosion Control in Oilfield

“…Among these methods, squeeze treatment is perhaps the most widely adopted approach in managing scale and corrosion threats at the downhole and reservoir [135,136]. During a squeeze treatment, the inhibitor solution or pill will be injected into the reservoir [137]. These inhibitors react with formation rock by adsorbing or precipitating onto rock material surfaces to fix the inhibitor in the formation pore space [138,139].…”

Review of Iron Sulfide Scale Removal and Inhibition in Oil and Gas Wells: Current Status and Perspectives

“…Under the harsh field conditions of sour gas wells, it is essentially required to use efficient inhibitors through continuous or squeeze treatment inhibition methods rather than using conventional inhibitors. Squeeze treatment is based on the continuous pushing of the inhibitor into the production formation for fixing it there to provide constant inhibition to the growth of scales crystals . This is because of the very high iron concentration of 60,000–80,000 ppm during acid treatment and sulfide concentration of 10,000–15,000 ppm at downhole conditions .…”

“…Squeeze treatment is based on the continuous pushing of the inhibitor into the production formation for fixing it there to provide constant inhibition to the growth of scales crystals. 109 This is because of the very high iron concentration of 60,000−80,000 ppm during acid treatment and sulfide concentration of 10,000−15,000 ppm at downhole conditions. 58 Downhole squeeze treatment of tetrakis(hydroxymethyl)phosphonium sulfate (THPS) was successfully implemented with no operational challenges and with a significant reduction in FeS scales deposition rate.…”

Iron Sulfide Scale Inhibition in Carbonate Reservoirs

“… 17 Scale inhibitors work by either altering morphology of the growing sites and adsorption effects. 16 The adsorption effect is explained by the fact that scale-inhibiting molecules bind to the areas where scale-generating molecules should be settled down. 16 The underlying theory behind adsorption effects is that those scale inhibitors retain in the sites where scale generating molecules should deposit.…”

“… 16 The adsorption effect is explained by the fact that scale-inhibiting molecules bind to the areas where scale-generating molecules should be settled down. 16 The underlying theory behind adsorption effects is that those scale inhibitors retain in the sites where scale generating molecules should deposit. The result would be a lack of growth in scale crystals and an inability to adsorb onto the internal rock surface.…”