Fluid-loss control additives

Fluid loss control agents are additives that control leak-off of the aqueous phase of cement slurry into the formation.

Function: Fluid Loss Control

Application: Temperatures from 4 – 93 degC

Description: Tan powder

Primary purpose: Hydroxyethylcellulose type fluid loss control additive effective in cement slurries up to temperatures of 93 degC. FLAC increases the viscosity of a slurry. Mixing difficulties can be expected if heavy slurry densities are required. Limit the application to approximately 15 lbm/gal (1.80 SG).

Guidelines for use: FLAC can be used in either freshwater or seawater slurries. Limited testing indicates that FLAC used in slurries containing up to 37% BWOW salt provides moderate fluid loss control. Concentrations of 0.4 – 3.0 % BWOC will provide fluid loss values in the range of 50 – 200 ml/30 min. A certain amount of dispersion is needed to obtain these low fluid loss values. FLAC has retarding effect on cement slurry. Retarders will usually not be required at a BHCT less than 52 degC.

Function: Fluid Loss Control

Application: Up to 204 degC

Description: White powder

Primary purpose: Cement additive that improves the fluid loss control. It is a high molecular weight, water soluble polymer with fluid-loss control properties observed at low concentrations ranging from 0.1 % to 0.8 % BWOC, depending on the temperature.

Guidelines for use: As all water-soluble fluid loss additives for cement (FLAC), the additive increases the slurry viscosity, but significantly less than other existing water soluble fluid loss additives. At concentrations above 0.5 % BWOC the additive has viscosifying effect. It has non-retarding effect on slurry above 21 degC. Low sensitivity of performance to the cement brand has been proved from 27 degC to 204 degC for medium-density slurries in fresh water.