Anti-Settling Additives

• Petrochem - Anti-Settling Agent Powder & Liquid (P-ASA & P-ASAL) is a powdered and liquid anti-settling additive created to reduce free water, sedimentation, and density gradation; which is collectively known as slurry instability when preparing the concrete. Increasing rheological values will provide a stability improvement within slurries; which is a huge advantage when using a cement anti-settling agent. Other advantages of these additives include:
  • Both have minimal impacts on thickening time
  • Both have minimal effects on fluid loss control
  • Both have little impact on compressive strength development
  • Both can be used within temperatures from 80°F to 300°F 
  • Designed to improve suspension properties for dispersed cement slurries

These three properties depend on maintaining a solids-to-fluid ratio throughout the wellbore:

• Permeability
• Compression Strength
• Zonal Isolation

Under wellbore conditions within a graduated cylinder, free water in cement slurries can take the form of channels along one side of a deviated wellbore or pockets of water within a vertical column of set cement. Our anti-settling agent for oilfield cement is important because free water is present in all cement but reacts differently with additives:

• Compatible with fluid loss additives at proper concentrations
• Compatible with retarders with temperatures under 125°F
• Works ok with accelerators due to sodium chloride
• Compatible with extenders
• Compatible with weighting agents when properly mixed - added benefit here because the P-ASA helps improve the suspension of the weighting agents thus helping resolve maintenance issues within the slurry property. 

• Petrochem - High-Temperature Anti Settling Powder (P-HTAS) is a powdered cement anti-settling agent designed to prevent sedimentation in cement slurries at bottom-hole temperatures under 500°F and is particularly effective in stabilizing over-dispersed cement slurries. Here are just a couple of the advantages of using anti-settling agents:
  • Compatible with Petrochem additives and Portland cement
  • Increases rheology of P-HTAS stabilized slurries - Requires an increase in the critical pump rate for turbulent flow
  • Excellent with other additives that are experiencing a dispersing side effect and offsetting the effects within the slurry
  • Excellent with slurries that are overdispersed due to a cement brand by preventing free-water and settling
  • Great with light and heavyweight cement slurries with densities from 12 gallons up to 22 gallons
  • Used to help stabilize low-density slurries
  • Enhances fluid-loss control additives with a slight retarding effect
  • Reducing concentration levels of P-HTAS
  • Dry blend instead of prehydrating
  • Changing the mixing method to increase the mixing energy including batch mixing instead of jet mixing

The mixing energy needs to be considered a factor within the design phase of a P-HTAS slurry. Lower mixing energies in the field and high mixing energies in a laboratory will produce high fluid loss values and higher rheologies.  Processes should be changed in order to take into consideration of field mixing problems including:

• Reducing concentration levels of P-HTAS
• Dry blend instead of prehydrating
• Changing the mixing method to increase the mixing energy including batch mixing instead of jet mixing

What is a stable slurry?

A stable slurry is when a cement slurry remains consistent. There are two ways to measure the slurry stability; through a free-fluid test and a sedimentation test.  When the terminal velocity of the particles is very minuscule, this is when stable slurries have been acquired.

What are the rheological properties of concrete?

Rheological properties of concrete deal with the water in the cement and the chemical interactions in the cement. The rheological properties of concrete rely on the formation and gradation of the aggregates within the cement mixture. The rheological properties of concrete is how the materials in the cement circulate.

How does gradation affect the concrete mix?

The gradation affects the concrete mix because it decides how much paste will be required in order for the concrete to be viable. The gradation is a vital aspect to increase or decrease the durability of the cement. The density and workability of the mix are directly correlated to the grading of aggregate. 

Contact an Anti Settling Specialist today

At Petrochem, our oil and gas anti-settling additives help to increase rheological values which in exchange reduces sedimentation, free water, and density gradation. Water separation is an occasional problem that happens for field workers that need a solution to make sure the water/cement ratio is close to perfect to get the best product out of a slurry. Contact a concrete additive manufacturer today to learn how anti-settling additives can help your businesses’ needs in the oil field industry.