Acid Max

Water with Scaling Tendencies

Acid Max sticks are water soluble sticks containing a combination of acid, surfactant, dispersing agent, iron sequestrator, and inhibitor in solid stick form. Acid Max sticks 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 stick treatments. Some wells have gone on vacuum and taken water by gravity. Acid Max sticks have some limited uses in oil wells, gas wells, and water supply wells.

Dissolve Rate

Acid Max sticks are very economical (as compared to conventional scale removal operations) and can eliminate or delay the need for HC1 acid treatments. Continuous treatment with Acid Max sticks can extend the time period between future scale removal operations (especially after a conventional acid or clean-out job). Acid sticks are less corrosive to steel pipe than conventional liquid HC1 acid jobs because most of the acid generated by the stick is released down hole. Conventional liquid HC1 acid reacts with the steel, rust, and scale inside the pipe all the way down the well. Acid Max sticks are corrosion inhibited and mildly corrosive to steel. Acid Max sticks are safe and easy to use by less experienced field personnel. Acid Max sticks are safe to use in cement lined tubing and plastic lined pipe. Continued treatments over long periods of time through a by-pass feeder into cement lined pipe should be avoided.

Applications

The number of Acid Max sticks to be used is based on the number of feet of perforated interval or open hole and severity of scale build-up. Field tests indicate the best results were achieved by using a large initial slug treatment (1.8 to 5.4 lbs. of stick per foot of interval) followed by smaller periodic treatments (about half the initial slug amount). Recommended usage is 2-6 of the 1 1/4 x 15” sticks per foot of interval. The most common procedure is to shut-in the well and drop the sticks through the lubricator and return well to injection. This procedure is best for open-hole, no rat-hole, low rate wells, or wells deeper than 3,300 feet. For shallow perforated wells with rat-hole drop sticks and leave well shut-in about 15 minutes or until sticks fall to the perforations then return well to injection. The time in minutes for the sticks to fall to the perforations (assuming well is shut-in with fluid at surface) is equal to the depth or perforations divided by 110. (Time, min + depth, ft/110). Acid Max sticks can be introduced to the system through the water supply tank. However, dropping the sticks directly into a well is best because not as much dilution will occur. In a well with tubing obstructions or small valve openings, Acid Max sticks can be successfully used by first dissolving the sticks in fresh water and then pumping or pouring the solution into the well.

Water with Scaling Tendencies

Dissolve Rate

Applications

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