Cement Accelerators

Accelerators are materials that shorten pumping time and/or time to develop compressive strength when added to Portland cement blends. They are primarily used in wells having a BHST less than 120°F.

Bulk Cement

The oil industry purchases cement manufactured according to API classifications as published in API Standards.

Cement Blends

Certain combinations of cements and additives have been determined that impart desirable properties to certain well conditions.  These combinations become commonplace and become a blend. 

Defoamers

Cement slurries tend to foam or entrain air during mixing operations. The air makes it difficult to achieve the desired slurry density unless anti-foamers, or defoamers, are used.

Cement Fluid Loss Additives

As cement is pumped across a permeable rock surface under pressure, cement filtrate or water is lost or squeezed out of the cement into the formation cement fluid loss must be controlled to obtain the right rheological properties for placing the cement.

Cement Friction Reducers

Dispersants are added to cement slurries to facilitate blending at densities greater than the API recommended densities without using excess water. Other advantages of using dispersants are reduced friction pressure and  reduced critical pump rates for turbulence.

Light Weight Additives

Extenders increase the yield of a sack of cement and conversely lower the slurry density and hydrostatic pressure. They can be selected to react or non-react with the cement to provide the desired properties.

Lost Circulation

Lost circulation differs from fluid loss in that fluid loss is the measure of cement filtrate lost to the formation, whereas lost circulation is the loss of the entire fluid/solid slurry. Lost circulation materials are inert plugging particulate which seal cracks or vugular formations.

Preflushes and Spacers

A cement preflush or spacer fluid separates the drilling mud from the cement slurry. Drilling mud is not compatible with cement slurry. Preflushes and spacers remove drilling mud from the annulus ahead of the cement. Flushes are designed to be compatible with water and or oil.

Retarders

Cementing deep, hot wells require the use of a chemical retarder to slow down the thickening time of cement slurry.

Special Additives

Miscellaneous cement additives are required for certain properties not generally required.  Special additives are required for steam applications and certain corrosive containment applications.

Weighting Materials

When a cementing problem requires a high density slurry to control the bottom hole pressure and achieve a successful job, weighting materials are the solution They are chemically inert particles with a high specific gravity. While they do not affect the pumping time of the cement slurry they do add viscosity.