Cement composition
AssigneeAtlantic Richfield Company
InventorsRobert B. Carpenter, J. Benjamin Bloys, David L. Johnson
Life of this patent
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Abstract
A cement slurry composition suitable for well bore cementation is provided containing as an essential component a synthetic hectorite clay in amount sufficient to reduce free water formation and solids segregation.
Claims15
A cement slurry composition useful for cementing oil wells comprising cement and water together with an amount of synthetic hectorite clay sufficient to reduce solids segregation and free water development.
A settable thixotropic material comprising a synthetic hectorite clay and a settable cementitious substance, the material containing said hectorite clay in an amount sufficient to provide a reversible gelling time of less than 60 seconds.
A slurry composition comprising cement and water together with synthetic hectorite clay in an amount sufficient to provide said composition with a rheological shear stress versus shear rate curve which is flat.
A cement slurry composition comprised of cement and water, and also containing a synergistic combination comprised of a synthetic hectorite and at least one additive selected from the group consisting of (a) sodium naphthalene sulfonate condensed with formaldehyde;
- calcium, sodium, phosphorous, zirconium, or chromium lignosulfonate salts;
- gluco-delta-lactone;
- Na-ethylenediamine tetra acetic acid;
- citric acid;
- tartaric acid;
- calcium and sodium gluco heptanate;
- erythorbic acid;
- sodium sulfonated maleic anhydride;
- sulfonated acetone condensed with formaldehyde;
- polyacrylates;
- sulfonated tannins;
- acrylate/acrylamide copolymers;
- acrylomido methyl propane sulfonate copolymers;
- interpolymers of acrylic acid;
- allyloxybenzene sulfonate;
- allyl sulfonate and non-ionic monomers;
- and (b) tetrasodium pyrophosphate or sodium tripolyphosphate in amounts sufficient to substantially increase low shear viscosity and produce a rheology curve characterized by a ratio of shear stress at 300 rpm to shear stress at 3 rpm of 4 or less.
Dependencies are inferred from the claim text.