Set retarded ultra fine cement compositions and methods

A method of cementing a subterranean zone penetrated by a well bore at a temperature in the range of from about 140.degree. F. to about 245.degree. F. comprising the steps of:

• pumping a set retarded ultra fine cement composition into said zone, said cement composition consisting essentially of,
• an ultra fine hydraulic cement having a particle size no greater than about 30 microns and a Blaine Fineness no less than about 6000 square centimeters per gram,
• sufficient water to form a pumpable slurry, and
• a set retarder comprised of a methylenephosphonic acid derivative present in said slurry in an amount in the range of from about 0.05% to about 2.5% by weight of dry cement therein, said methylenephosphonic acid derivative being selected from the group consisting of:
• compounds having the general formula:
• ##STR9## wherein:
• R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen, --CH.sub.2 PO.sub.3 (X).sub.2 or --CH.sub.2 CH.sub.2 --O--PO.sub.3 (X).sub.2 with the limitation that one of R.sub.1, R.sub.2 and R.sub.3 is always --CH.sub.2 PO.sub.3 (X).sub.2 or --CH.sub.2 CH.sub.2 --O--PO.sub.3 (X).sub.2 ;
• X is hydrogen, an alkali metal cation, ammonium, a protonated amine or an alkaline earth metal cation in which case there is only one X per methylenephosphonate group;
• and
• at least one X is hydrogen which is associated with the nitrogen atom by way of an intramolecular hydrogen bond between the nitrogen atom and an oxygen atom attached to a phosphorus atom;
• compounds having the general formula:
• ##STR10## wherein:
• n is an integer from 1 to 4;
• R.sub.1 is hydrogen or --CH.sub.2 PO.sub.3 (X).sub.2 ;
• R.sub.2 is hydrogen, --CH.sub.2 PO.sub.3 (X).sub.2 or --CH.sub.2 CH.sub.2 N(R.sub.3).sub.2 wherein R.sub.3 is hydrogen or --CH.sub.2 PO.sub.3 (X).sub.2 ;
• X is hydrogen, an alkali metal cation, ammonium, a protonated amine or an alkaline earth metal cation in which case there is only one X per methylene phosphonate group;
• and
• at least one of R.sub.1, R.sub.2 or R.sub.3 is --CH.sub.2 PO.sub.3 (X).sub.2 and one X is hydrogen which is associated with a nitrogen atom by way of an intramolecular hydrogen bond between the nitrogen atom and an oxygen atom attached to a phosphorus atom;
• compounds having the general formula:
• ##STR11## wherein:
• n is an integer from 2 to 6;
• R is hydrogen, --CH.sub.2 PO.sub.3 (X).sub.2 or --CH.sub.2 CH.sub.2 N(R.sub.1).sub.2 wherein R.sub.1 is hydrogen or --CH.sub.2 PO.sub.3 (X).sub.2 ;
• X is hydrogen, an alkali metal cation, ammonium, a protonated amine or an alkaline earth metal cation in which case there is only one X per methylene phosphonate group;
• and
• at least one R is --CH.sub.2 PO.sub.3 (X).sub.2 and one X is hydrogen which is associated with a nitrogen atom by way of an intramolecular hydrogen bond between the nitrogen atom and an oxygen atom attached to a phosphorus atom;
• and
• compounds having the general formula:
• ##STR12## wherein:
• R.sub.1 is hydrogen or --CH.sub.3 ;
• R.sub.2 is PO.sub.3 (X).sub.2 or --CH.sub.2 PO.sub.3 (X).sub.2 ;
• X is hydrogen, an alkali metal cation, ammonium, a protonated amine or an alkaline earth metal cation in which case there is only one X per methylene phosphonate group;
• and
• when nitrogen is present, at least one X is hydrogen which is associated with the nitrogen atom by way of an intramolecular hydrogen bond between the nitrogen atom and an oxygen atom attached to a phosphorus atom;
• and
• allowing said cement composition to set into a hard substantially impermeable mass in said zone.