Self-pressurizing soluble alkali silicate for use in sealing subterranean spaces
View Patent ↗Compositions and methods are disclosed for sealing subterranean spaces such as natural or induced fractures, vugs or annular spaces. The composition is composed of a base fluid consisting of a soluble alkali silicate, a gas generating additive, water, solids, and a setting agent. The gas generating additive may be coated or uncoated. The gas generating additive may also be in the form of a slurry. In the case of coated additives, the coating may act as a retarder or an accelerator to the expansion and setting agent of the soluble alkali silica. Similarly, the choice of carrier fluid in a slurry may retard or accelerate the expansion and setting of the alkali silicate-based plug.
1. A method for sealing subterranean spaces comprising the step of introducing into a downhole a base fluid containing a soluble alkali silicate, a gas generating additive, a setting agent, water, and solids, whereby the soluble alkali silicate promotes a gas generating reaction wherein the gas generating additive reacts with water to produce a gas, causing the soluble alkali silicate to expand and self-pressurize in a subterranean space, thereby sealing the subterranean space.
2. The method of claim 1 wherein said gas generating additive is one of a metal and a metal salt, wherein the soluble alkali silicate promotes an oxidation reaction of the one of a metal and a metal salt with water.
3. A method for sealing a subterranean space comprising the steps of:
a. introducing into a downhole a base fluid containing a soluble alkali silicate, a gas generating additive, water, solids, and a setting agent; and
b. said soluble alkali silicate promoting a gas generating reaction of said gas generating additive with water to produce a gas;
wherein said gas produced by said reaction causes said alkali silicate to expand and self-pressurize in said downhole, thereby sealing the subterranean space.
4. The method of claim 3 further comprising the step
(c) said setting agent causing said expanded alkali silicate to set in said downhole.
5. The method of claim 4 wherein said gas generating additive is one of a metal and a metal salt, wherein the soluble alkali silicate promotes an oxidation reaction of the one of a metal and a metal salt with water.
6. The method of claim 5 wherein said setting agent is one of a metal and a metal salt.