Drilling fluids that include water-soluble acid catalysts and uses for such

A sealed subterranean petroleum formation comprising:

• a subterranean wellbore positioned adjacent a subterranean petroleum formation;
• and
• a drilling fluid positioned in the subterranean wellbore, the drilling fluid comprising:
• a base fluid comprising an aqueous or non-aqueous solution;
• one or more formaldehyde-based resins, where the weight ratio of the one or more formaldehyde-based resins to the base fluid is from 1:100 to 50:100;
• optionally latex, where if latex is present in the drilling fluid, the weight ratio of the latex to the total weight of the drilling fluid is less than or equal to 10:100 and
• optionally polyvinyl alcohol or vinyl alcohol copolymers, where if the polyvinyl alcohol or vinyl alcohol copolymers are present in the drilling fluid, the weight ratio of the sum of the polyvinyl alcohol and vinyl alcohol copolymers to the total weight of the drilling fluid is less than or equal to 1.5:100;
• and
• one or more water-soluble acid catalysts in an amount sufficient to reduce the pH of the drilling fluid to less than or equal to 6.

A method for sealing a subterranean wellbore, the method comprising:

• introducing a drilling fluid into a subterranean wellbore, the subterranean wellbore positioned adjacent to a subterranean petroleum formation, where the drilling fluid comprises:
• a base fluid comprising an aqueous or non-aqueous solution;
• one or more formaldehyde-based resins, where the weight ratio of the one or more formaldehyde-based resins to the base fluid is from 1:100 to 50:100;
• optionally latex, where if latex is present in the drilling fluid, the weight ratio of the latex to the total weight of the drilling fluid is less than or equal to 10:100;
• and
• optionally polyvinyl alcohol or vinyl alcohol copolymers, where if the polyvinyl alcohol or vinyl alcohol copolymers are present in the drilling fluid, the weight ratio of the sum of the polyvinyl alcohol and vinyl alcohol copolymers to the total weight of the drilling fluid is less than or equal to 1.5:100;
• and
• contacting one or more water-soluble acid catalysts with the drilling fluid in an amount operable to transition the drilling fluid from a liquid state to a gelled state such that the apparent viscosity at 300 rpm and 25° C. of the drilling fluid in the gelled state is at least 50,000 centiPoises.