The reversion rate of GYP CRYSTALS to orthophosphate increases with increasing temperature, higher phosphate concentration and lower pH. The effectiveness of any inorganic phosphate as a scale inhibitor is lost when it reverts to orthophosphate.
Mechanical bridging of the GYP CRYSTALS may occur in wells having small annuli. This will prevent the material from reaching the fluid level. Also, some wells have a rat hole at the bottom which is by-passed by produced fluid flowing from the formation to the tubing. Where these possibilities exist, poly (meta) phosphate counts should be made on the produced water to determine if the phosphate is going into solution.
The solubility of GYP CRYSTALS is controlled by its particle size, water temperature and other ions in solution. GYP CRYSTALS are highly soluble in fresh water; thus, the entire treatment may be solubilized too rapidly to afford long term protection. GYP CRYSTALS are not recommended for wells having bottom-hole temperatures above 150ºF.