CLASS G (HSR) - API SPEC 10A
The types of cement are categorized according to the American Petroleum Institute (API) Specification10A standards, which has identified 8 classes of cement according to the depth of the well, the temperature and pressure. Cement is also classified in grades: Ordinary (O), Moderate Sulfate Resistant (MSR), and High Sulfate Resistant (HSR). Sulfate resistance is based upon the C3A (Tricalcium Aluminate) content, which has a bearing on the durability of the cement under sulfate attacks.
The product obtained by grinding Portland cement clinker, consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an intergrouned addition. No addition other than calcium sulfate or water, or both, shall be interground or blended with clinker during manufacture of class G well cement. This product is intended for use as basic well cement.
- Exploration for and the production of oil and gas
- As a sealing water wells
- In waste disposal wells
OIL WELL CEMENT (OWC)
|Chemical Composition||API Standard requirement||Average Values Class G-HSR|
|Loss on ignition||≤ 3.0 %||< 2 %|
|Insoluble residue||≤ 0.75 %||< 0,6 %|
|MgO||≤ 6.0 %||< 2 %|
|SO3||≤ 3.0 %||< 3 %|
|Alkali content (expressed as Na2O equivalent)||≤ 0.75 %||< 0,7 %|
|C3S||48 – 65 %||> 59 %|
|C3A||≤ 3.0 %||< 2 %|
|C4AF + 2C3A||≤ 24 %||< 18 %|
|Free fluid content||≤ 5.9 %||< 4,5 %|
|Compressive Strength 8h, 38°C||≥ 2.1 MPa||> 4,5 Mpa|
|Compressive Strength 8h, 60°C||≥ 10.3 Mpa||> 14 Mpa|
|Thickening time||90 – 120 min||> 100|
|Maximum consistency (15-30 min)||≤ 30 Bc||< 18 Bc|
- In big bags 1.5 ton.