Claims
- 1. A composition for forming a silicate cement sufficient to close a zone of a formation to fluid flow consisting of:
- (a) an aqueous solution of a silicate selected from a member of the group consisting of alkali metal silicate, ammonium silicate and organoammonium silicate which is contained in said solution in an amount of from about 10 to about 60 wt %;
- (b) a spacer volume of a water-miscible organic solvent selected from the group consisting of methanol, ethanol, higher alcohols, glycols, ketones, tetrahydrofuran and dimethyl sulfoxide; and
- (c) a water-miscible organic solvent containing an alkylpolysilicate in an amount of about 10 to about 100 wt % and a member selected from the group consisting of an inorganic salt or chelated calcium in an amount of from about 10 to about 40 wt % sufficient to react with said organoammonium silicate, alkali metal or ammonium silicate so as to form a permeability retentive silicate cement within a zone of a formation so as to close said zone to fluid flow.
- 2. The composition as recited in claim 1 where the alkali metal silicate comprises ions of sodium, potassium, or lithium, and mixtures thereof.
- 3. The composition as recited in claim 1 where the alkali metal silicate has a silicon dioxide to metal oxide molar ratio of less than about 4.
- 4. The composition as recited in claim 1 where said alkylpolysilicate comprises tetramethyl or tetraethylorthosilicates and said salt is selected from a member of the group consisting of calcium chloride hydrate and chelated calcium chloride.
- 5. The composition as recited in claim 1 where said silicate cement withstands temperatures in excess of about 400.degree. F.
- 6. The composition as recited in claim 1 where the silicate cement withstands a temperature in excess of about 400.degree. F. and a pH of about 7 or more.
- 7. The composition as recited in claim 1 where in (c) said alkylpolysilicate is a hydrolysis-condensation product of alkylorthosilicate according to the equation below: ##STR2## where n.ltoreq.2 and R=C.sub.1 -C.sub.10.
Parent Case Info
This is a division of application Ser. No. 07/810,662, filed Dec. 19, 1991 U.S. Pat. No. 5,257,664 which is a continuation-in-part of application Ser. No. 07/622,588, filed Dec. 3, 1990 U.S. Pat. No. 5,103,907.
US Referenced Citations (19)
Divisions (1)
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810662 |
Dec 1991 |
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Continuation in Parts (1)
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622588 |
Dec 1990 |
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