Single step calcium sulfate scale removal at high temperature using tetrapotassium ethylenediaminetetraacetate with potassium carbonate

Summary: In this study, calcium sulfate was used as a weighting additive in drilling fluids for the first time, showing higher solubility and dissolution performance compared to commonly used calcium carbonate. The calcium sulfate-based filter cake demonstrated greater solubility with organic and inorganic acids, leading to improved removal efficiency with a new formulation containing GLDA chelating agent and potassium carbonate. Removal efficiency reached 100% after 10 hours in a solution of 20 wt% GLDA and 10 wt% potassium carbonate at 100 degrees C.