Set retarding additives, cement compositions and methods
AssigneeHalliburton Company
InventorLarry Eoff
Life of this patent
Estimating the term…
Abstract
The present invention provides set retarding additives, set retarded hydraulic cement compositions including such additives and methods of using the cement compositions for cementing zones in wells. The set retarding additives are graft polymers comprised of a backbone sugar having one or more pendant polymerized or copolymerized vinyl compounds grafted thereto.
Claims20
A graft polymer additive for retarding the set of a hydraulic cement composition comprised of:
- a backbone sugar having the general formula:
- ##STR7## wherein:
- A is a group selected from ##STR8## B is a group selected from ##STR9## R.sub.1 is selected from hydrogen, hydroxyl or --CH.sub.2 OH and can be the same or different in the above A, B and D groups;
- R.sub.2 is selected from hydrogen or oxygen;
- m is an integer in the range of from 1 to 3;
- n is an integer in the range of from 1 to 3;
- and
- p is an integer having a value of 0 or 1;
- said backbone sugar having grafted thereto one or more pendant polymerized or copolymerized vinyl compounds selected from the group consisting of 2-acrylamido-2-methyl propane sulfonic acid, vinyl phosphonic acid, vinyl sulfonic acid, acrylic acid, acrylonitrile and N,N-dimethylacrylamide.
A set retarded hydraulic cement composition comprising:
- hydraulic cement;
- sufficient water to form a pumpable slurry;
- and
- a graft polymer set retarding additive comprised of a backbone sugar having the general formula:
- ##STR10## wherein:
- A is a group selected from ##STR11## B is a group selected from ##STR12## R.sub.1 is selected from hydrogen, hydroxyl or --CH.sub.2 OH and can be the same or different in the above A, B and D groups;
- R.sub.2 is selected from hydrogen or oxygen;
- m is an integer in the range of from 1 to 3;
- n is an integer in the range of from 1 to 3;
- and
- p is an integer having a value of 0 or 1;
- said backbone sugar having grafted thereto one or more pendant polymerized or copolymerized vinyl compounds selected from the group consisting of 2-acrylamido-2-methyl propane sulfonic acid, vinyl phosphonic acid, vinyl sulfonic acid, acrylic acid, acrylonitrile and N,N-dimethylacrylamide. vinyl sulfonic acid, acrylic acid, acrylonitrile and N,N-dimethylacrylamide.
The composition of claim wherein said set retarding additive is present in said composition in an amount in the range of from about 0.1% to about 2% by weight of dry cement therein.
A method of cementing a subterranean zone penetrated by a well bore comprising the steps of:
- forming a pumpable set retarded cement composition comprised of hydraulic cement, sufficient water to form a pumpable slurry and a graft polymer set retarding additive comprised of a backbone sugar having the general formula:
- ##STR13## wherein:
- A is a group selected from ##STR14## B is a group selected from ##STR15## R.sub.1 is selected from hydrogen, hydroxyl or CH.sub.2 OH and can be the same or different in the above A, B and D groups;
- R.sub.2 is selected from hydrogen or oxygen;
- m is an integer in the range of from 1 to 3;
- n is an integer in the range of from 1 to 3;
- and
- p is an integer having a value of 0 or 1;
- said backbone sugar having grafted thereto one or more pendant polymerized or copolymerized vinyl compounds selected from the group consisting of 2-acrylamido-2-methyl propane sulfonic acid, vinyl phosphonic acid, vinyl sulfonic acid, acrylic acid, acrylonitrile and N,N-dimethylacrylamide.
Dependencies are inferred from the claim text.