Drilling fluids that include water-insoluble acid catalyst precursors
AssigneeSaudi Arabian Oil Company
InventorsVikrant Wagle, Abdullah Al-Yami, Abdulaziz Alhehal
Life of this patent
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Abstract
In accordance with one or more embodiments of the present disclosure, a drilling fluid may include a base fluid and one or more formaldehyde-based resins. The drilling fluid may further comprise one or more water-insoluble acid catalyst precursors or the reaction products of such water-insoluble acid catalyst precursors. The present disclosure also describes sealed subterranean petroleum formations that include such drilling fluids and methods for sealing subterranean wellbores by utilizing such drilling fluids.
Claims16
A drilling fluid comprising:
- a base fluid comprising an aqueous solution;
- a formaldehyde-based resin, where the weight ratio of the formaldehyde-based resin to the base fluid is from 1:100 to 50:100;
- a water-insoluble acid catalyst precursor, where the weight ratio of the sum of the water-insoluble acid catalyst precursor to the total drilling fluid is from 0.5:100 to 20:100;
- where the drilling fluid transitions from a liquid state to a gelled state when a pH of the drilling fluid is less than 6.
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 solution;
- a formaldehyde-based resin, where the weight ratio of the formaldehyde-based resin to the base fluid is from 1:100 to 50:100;
- a water-insoluble acid catalyst precursor, the weight ratio of the sum of the water-insoluble acid catalyst precursor to the total drilling fluid is from 0.5:100 to 20:100;
- where the drilling fluid transitions from a liquid state to a gelled state when a pH of the drilling fluid is less than 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 solution;
- a formaldehyde-based resin, where the weight ratio of the formaldehyde-based resin to the base fluid is from 1:100 to 50:100;
- introducing a water-insoluble acid catalyst precursor to the drilling fluid, where the water-insoluble acid catalyst precursor is converted to an acid catalyst in the drilling fluid in an amount operable to transition the drilling fluid from a liquid state to a gelled state;
- where the ratio of the water-insoluble acid catalyst precursor to the total weight of the drilling fluid after the contacting step is from 0.5:100 to 20:100;
- and
- where the drilling fluid transitions from the liquid state to the gelled state when a pH of the drilling fluid is less than 6.
Dependencies are inferred from the claim text.