SELECT ACID CAPS are primarily used in water injection wells to remove carbonate scale and rust deposits and lower injection pressures. Injection pressure drops of several hundred PSI have been observed following ACID CAP treatments. Some wells have gone on vacuum and taken water by gravity. Success has also been experienced in some producing oil wells, gas wells and water supply wells.
SELECT ACID CAPS, after removing the plastic wrapper, are dropped directly into the well or introduced to the system through the water supply tank. Dropping the stick directly into a well is best because not as much dilution will occur. In a well with tubing obstructions or small valve openings, ACID CAPS may be successfully used by first dissolving the sticks in fresh water and then pumping or pouring the solution into the well.
ACID CAPS are very economical (as compared to conventional scale removal operations) and can eliminate or delay the need for HCl acid treatments. Continuous treatment with ACID CAPS (especially after a conventional acid or clean-out job) can extend the time period between future scale removal operations. ACID CAPS are less corrosive to steel pipe than conventional liquid HCl acid jobs, because most of the acid generated by the stick is released down-hole. Conventional liquid HCl acid reacts with the steel, rust and scale inside the pipe all the way down the well.
ACID CAPS are safe to handle and easy to use by less experienced field personnel; however, like all acids, contact with eyes or skin should be avoided. The plastic protective wrapper when removed before dropping stick can be used as a protective glove while handling the stick. ACID CAPS are safe to use in cement lined tubing and plastic line pipe. Continued treatments over long periods of time through a by-pass feeder into cement lined pipe should be avoided.