Scale DissolversThe precipitation of insoluble mineral scale deposits is a common event during the production of hydrocarbon and associated produced water, causing formation damage. Precipitation of inorganic scale is not just limited to producing wells. Inorganic scale deposition can occur during and after injection operations in the injector wellbore, near the injection-well bottom-hole, in the reservoir between the injector and the producer, at the skin of the producer well, in the producer wellbore, and at the surface facilities.
In the production side, scale deposition can block perforations, casing, production tubing, valves, electro-submergible pumps and downhole completion equipment, clogging the wellbore and severely constricting fluid flow. Scale deposition curtails the production rate of oil and gas wells and results in an additional operating cost for treatment, protection, and removal. It also costs the petroleum industry millions of dollars each year and is the leading cause of production decline worldwide.
Carbonate scales can be formed when pressure or temperature changes in flowing fluid lead to the break out of dissolved carbon dioxide. Mixing of incompatibles brines can lead to the formation of sulphate scales.
Scale control through chemical inhibition is the preferred method of maintaining well productivity. However, when scale forms on the wellbore, scale-removal techniques must be quick and no damaging to the wellbore, tubing, or formation environment, and effective at preventing reprecipitation.