scope:

1. Scope

1.1 WELL CEMENTS

Well cement slurries can be based on (but are not limited to) one of the API classes and grades of cement identified in this section and shown in Table 1. API well cements are produced by grinding Portland cement clinker, generally consisting of hydraulic calcium silicates and aluminates and usually containing one or more of the forms of calcium sulfate as an interground addition.

API cements are graded according to sulfate resistance. Three grades are defined: ordinary (O), moderate sulfate-resistant (MSR), and high sulfate-resistant (HSR).

1.2 API CEMENT CLASSES

The following is a brief discussion of the differences and similarities among API classes of cement.

1.2.1 Class A

This product is intended for use when special properties are not required. It is available only in ordinary (O) grade. Class A cement is similar to ASTM C 150, Type I with regard to both chemistry and fineness. Processing additions may be used in the manufacture of Class A cement provided such materials in the amounts used have been shown to meet the requirements of ASTM C 465. Specification testing of Class A cement slurries requires 46 percent water (100 parts dry cement by weight to 46 parts mixing water by weight) according to API Specification 10A.

1.2.2 Class B

This product is intended for use when conditions require moderate or high sulfate-resistance. Class B cement is similar to Class A cement except that it is available in both moderate (MSR) and high sulfate-resistant (HSR) grades. The MSR grade is similar to ASTM C 150, Type II with regard to both chemistry and fineness. The HSR grade is similar to ASTM C 150 Type V with regard to both chemistry and fineness. Specification testing of Class B cement slurries requires 46 percent water (100 parts dry cement by weight to 46 parts mixing water by weight) according to API Specification 10A.

1.2.3 Class C

This product is intended for use when conditions require high early strength; it is typically the most finely ground of all API classes of well cement. It is available in ordinary (O),

moderate sulfate-resistant (MSR), and high sulfate-resistant (HSR) grades. Class C (O) cement is similar to ASTM C 150, Type III. Processing additions may be used in the manufacture of Class C cement provided such materials in the amounts used have been shown to meet the requirements of ASTM C 465. Specification testing of Class C cement slurries requires 56 percent water (100 parts dry cement by weight to 56 parts mixing water by weight) according to API Specification 10A.

1.2.4 Class D

This product is intended for use under conditions of moderately high temperatures. Specifications for Class D cement cover moderate sulfate-resistant (MSR) and high sulfate-resistant (HSR) grades. Processing additions may be used in the manufacture of the cement provided such materials in the amount used have been shown to meet the requirements of ASTM C 465. Suitable set-modifying agents are typically interground or blended during manufacture. Specification testing of Class D cement slurries requires 38 percent water (100 parts dry cement by weight to 38 parts mixing water by weight) according to API Specification 10A.

1.2.5 Class E

This product is similar to Class D cement. It is intended for use under conditions of high temperature. Specification testing of Class E cement slurries requires 38 percent water (100 parts dry cement by weight to 38 parts mixing water by weight) according to API Specification 10A.

1.2.6 Class F

This product is similar to Class D cement. It is intended for use under conditions of extremely high temperatures. Specification testing of Class F cement slurries requires 38 percent water (100 parts dry cement by weight to 38 parts mixing water by weight) according to API Specification 10A.

1.2.7 Class G

This product is intended for use as a basic well cement. No additions other than calcium sulfate or water, or both, shall be interground or blended with clinker during manufacture. It is available in moderate sulfate-resistant (MSR) and high sulfate-resistant (HSR) grades. Specification testing of Class G cement slurries requires 44 percent water (100 parts dry cement by weight to 44 parts mixing water by weight) according to API Specification 10A.

1.2.8 Class H

This product is intended for use as a basic well cement. Class H cement is similar to Class G cement. Class H cement is typically more coarsely ground than Class G cement. Specification testing of Class H cement slurries requires 38 percent water (100 parts dry cement by weight to 38 parts mixing water by weight) according to API Specification 10A.