Claims
- 1. A method for forming a cement for controlling sand production through a consolidated gravel pack in an unconsolidated or loosely consolidated formation penetrated by a cased borehole where sand is placed within a washed-out area adjacent said borehole, comprising the steps of:
- a) injecting into said zone an aqueous hydroxide solution where the hydroxide is a member selected from the group consisting of an alkali metal hydroxide, ammonium hydroxide, or organoammonium hydroxide;
- b) injecting next into said zone a spacer volume of a water-immiscible hydrocarbonaceous liquid; and
- c) injecting thereafter a water-miscible organic solvent containing an alkylpolysilicate in an amount sufficient to react with said aqueous hydroxide solution so as to form a permeability retentive silica cement within said sand in a washed-out area which cement is of a strength sufficient to bind sand containing particles within the washed-out area and formation adjacent thereto while producing hydrocarbonaceous fluids and excluding formation fines or sand.
- 2. The cement as recited in claim 1 where the aqueous hydroxide solution comprises ions of sodium, potassium, or lithium, and mixtures thereof.
- 3. The cement as recited in claim 1 where in step c) the solvent is a member selected from the group consisting of methanol, ethanol, higher alcohols, glycols, ketones, tetrahydrofuran, and dimethyl sulfoxide.
- 4. The cement as recited in claim 1 where in step c) the hydroxide is contained in the aqueous solution in an amount of from about 20 to about 60 weight percent.
- 5. The cement as recited in claim 1 where alkylpolysilicate is contained in said solvent in an amount of about 10 to about 90 weight percent.
- 6. The cement as recited in claim 1 where said silica cement withstands temperatures in excess of about 1,000.degree. C. (1,832.degree. F.).
- 7. The cement as recited in claim 1 where the silica cement withstands pH's of 7 or lower.
- 8. The cement as recited in claim 1 where in step c) said alkylpolysilicate is the hydrolysis condensation product of alkylorthosilicate according to the equation: ##STR2## where n.ltoreq.2 and R=C.sub.1 -C.sub.10
- 9. The cement as recited in claim 1 where in step b) the spacer volume of fluid is a member selected from the group consisting of mineral oils, naphthas, C.sub.5 -C.sub.40 alkanes, and mixtures thereof.
- 10. The cement as recited in claim 1 where in step a) said organoammonium hydroxide is selected from a member of the group consisting of C.sub.1 through C.sub.10 alkyl or aryl groups and hetero atoms.
- 11. The cement as recited in claim 1 where in step a) said organoammonium hydroxide is tetramethylammonium hydroxide.
Parent Case Info
This is a division of copending application Ser. No. 07/810,468, filed on Dec. 19, 1991, now U.S. Pat. No. 5,211,235.
US Referenced Citations (19)
Divisions (1)
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Number |
Date |
Country |
Parent |
810468 |
Dec 1991 |
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