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US 4,054,462 AGranted
Method of cementing
AssigneeThe Dow Chemical Company
InventorDuane L. Stude
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AssigneeThe Dow Chemical Company
InventorDuane L. Stude
Estimating the term…
A cement composition is provided containing portland cement; calcium sulfate hemihydrate; urea; one or more retarders selected from the group consisting of a water soluble salt of a lignosulfonic acid, a low molecular weight hydroxypolycarboxylic acid and sodium, potassium, and lithium salts thereof, and an alkaline hexametaphosphate; and as optional ingredients, calcium chloride and/or a condensation product of mononaphthalene sulfonic acid and formaldehyde; said ingredients being present in amounts effective to provide a cement which will set within a desired period of time at temperatures below about 80.degree. F down to below freezing, e.g. 32.degree. F, to provide a monolithic mass having adequate strength and which also has a sufficient pumping time, i.e., setting time, at higher temperatures, i.e., above about 80.degree. F, so that it can be transported, i.e., pumped at such elevated temperatures without prematurely setting up.
A method of cementing in the low temperature zone of an environment having a low temperature zone below about 80.degree. F, which comprises:
The method of claim 5 wherein the environment is a borehole extending through a permafrost zone sufficiently deeply so that the borehole has a high temperature zone as defined in claim 36, comprising pumping the slurry through the permafrost zone into the high temperature zone, and then back into the permafrost zone before permitting the slurry to set up in said permafrost zone.
The method of claim 10 wherein the environment is a borehole extending through a permafrost zone sufficiently deeply so that the borehole has a high temperature zone as defined in claim 41, comprising pumping the slurry through the permafrost zone into the high temperature zone, and then back into the permafrost zone before permitting the slurry to set up in said permafrost zone.
The method of claim 16 wherein the environment is a borehole extending through a permafrost zone sufficiently deeply so that the borehole has a high temperature zone as defined in claim 47, comprising pumping the slurry through the permafrost zone into the high temperature zone, and then back into the permafrost zone before permitting the slurry to set up in said permafrost zone.
Dependencies are inferred from the claim text.