| abstract |
A workover process for removing calcium sulfate scale from oil wells includes introducing into the well and into contact with the scale an aqueous solution of sodium or potassium gluconate and sodium or potassium hydroxide. The weight ratio of gluconate to hydroxide is between about 2:1 and about 5:1 to give a direct solvent action. The concentration is between about 10 percent and about 30 percent by weight. The solvent can be used in connection with other workover steps such as the use of string shots, bailing, use of organic solvents such as paraffin solvents, acidizing, fracturing, and use of scale inhibitors. |