Drilling fluids that include water-soluble acid catalyst precursors or reaction products of such and uses for such drilling fluids

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 consisting of:
• a base fluid comprising an aqueous or non-aqueous solution;
• one or more formaldehyde-based resins, wherein the weight ratio of the one or more formaldehyde-based resins to the base fluid is from 10:100 to 20:100;
• optionally polyvinyl alcohol or vinyl alcohol copolymers, wherein if the polyvinyl alcohol or vinyl alcohol copolymers are present in the drilling fluid, the weight ratio of the sum of the polyvinyl alcohol or vinyl alcohol copolymers to the total weight of the drilling fluid is less than or equal to 1.5:100;
• one or more water-soluble acid catalyst precursors, wherein the weight ratio of the sum of the one or more water-soluble acid catalyst precursors to the total weight of the drilling fluid is from 0.5:100 to 2:100;
• a rheology modifier;
• a basic additive comprising sodium hydroxide;
• and
• one or more weighting agents, wherein the weight ratio of the one or more weighting agents to the base fluid is from 10:100 to 100:100;
• wherein:
• the drilling fluid is in a gelled state such that the apparent viscosity at 300 rpm and 25° C. of the drilling fluid is greater than or equal to 50,000 centiPoise;
• the drilling fluid has a density of from 50 pounds per cubic foot to 160 pounds per cubic foot;
• the one or more formaldehyde based resins comprises melamine-formaldehyde resin;
• the one or more water-soluble acid catalyst precursors comprises ethyl lactate;
• the weight ratio of the basic additive to the base fluid is from 0.001:100 to 5:100;
• the one or more weighting agents comprises barite.