Mud acid

{
  "id": "MLC-T-OAG-002443",
  "term": "Mud acid",
  "field": "Oil and gas",
  "definition": "A mixture of hydrochloric acid and hydrofluoric acid used to dissolve clays and other silicate minerals that damage sandstone permeability. The hydrochloric acid dissolves carbonates first and keeps the pH low so reaction products do not precipitate, while the hydrofluoric acid attacks the silicates. A common regular-strength blend is 12 percent hydrochloric acid with 3 percent hydrofluoric acid, and the hydrofluoric acid concentration is normally kept at 3 percent or less.",
  "subject": "Well Completions",
  "url": "https://mlchart.com/terminology/oil-and-gas/mud-acid/"
}