Accelerators

Accelerators are used to shorten the setting stages of the hydration process and to accelerate the hardness process and the rate of compressive strength development.

Function: Accelerator

Application: No limit

Description: White granules

Primary purpose: Sodium Chloride. Used when formations are sensitive to fresh water. Accelerates cement set when used at concentrations to 15% BWOW (by weight of water). At 18% BWOW, its effect is essentially neutral and thickening times are similar to those obtained with fresh water. Used above 18% BWOW, DOS044 retards setting of cement. Used above 18% to minimize leaching of salt formations.

Guidelines for use: High NaCl concentrations must be used in the slurry in the cases where a string of pipe must be set through a salt zone. A freshwater slurry in contact with salt formation will dissolve salt from the zone as the slurry sets. This prevents a firm bond of cement to the salt. However a slurry with DOS044 will remove less or no salt and will improve bonding to the salt formation. The minimum concentration needed for primary cementing applications across salt zones is generally considered 10-20% BWOW. Concentrations up to 37% (fully saturated) can be used in salt cavern cementing applications.

Function: Accelerator

Application: Below 55 degC

Description: White Solid

Primary purpose: Calcium chloride 78%. Typical concentration: 1 to 2% BWOC. Increases temperature of slurry when dissolved.

Guidelines for use: Calcium Chloride is used for early strength development at a concentration from 1% – 4% BWOC. The general rule is 2% DOS001 will reduce the thickening time by half and will increase the early strength by 50% – 75%.