Lost circulation material compositions utilizing spent drilling fluids and methods for using the same
AssigneeSaudi Arabian Oil Company
InventorsVikrant Wagle, Rajendra Kalgaonkar, Abdullah Al-Yami, Mohammad Alharthi
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Abstract
A lost circulation material (LCM) composition comprising a spent drilling fluid and a chemical activator. The spent drilling fluid may comprise an aqueous solution, contaminants comprising heavy metals, salt, or both, and an alkaline nanosilica dispersion. The chemical activator may comprise a water soluble hydrolysable polyester. The spent drilling fluid may also have a pH and a gel pH, wherein the pH of the spent drilling fluid is greater than the gel pH.
Claims20
A lost circulation material (LCM) composition comprising:
- a spent drilling fluid comprising
- an aqueous solution,
- contaminants comprising heavy metals, salts, or both, wherein:
- the heavy metals comprise ions of chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, cadmium, barium, mercury, lead, thorium, uranium, or combinations thereof;
- and
- the spent drilling fluid has a salinity of greater than or equal to 500,000 ppm, a heavy metals content of greater than or equal to 0.001 ppm, or both, and
- an alkaline nanosilica dispersion, wherein the spent drilling fluid has a pH and a gel pH, and the pH of the spent drilling fluid is greater than the gel pH;
- and
- a chemical activator comprising a water soluble hydrolysable ester.
A method for controlling lost circulation, the method comprising:
- introducing a spent drilling fluid comprising an aqueous solution, contaminants comprising salt, heavy metals, or both, and an alkaline nanosilica dispersion into a wellbore;
- introducing a chemical activator to the spent drilling fluid, the chemical activator comprising a water soluble hydrolysable ester;
- and
- allowing the chemical activator to hydrolyze and produce an acid, reducing a pH of the spent drilling fluid to less than a gel pH and converting the spent drilling fluid into a lost circulation material (LCM) composition, and wherein:
- the heavy metals comprise ions of chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, cadmium, barium, mercury, lead, thorium, uranium, or combinations thereof, and
- the spent drilling fluid has a salinity of greater than or equal to 500,000 ppm, a heavy metals content of greater than or equal to 0.001 ppm, or both.
Dependencies are inferred from the claim text.