D620 GASBLOK™ gas migration control additive is a latex additive that forms an impermeable barrier to prevent formation gas intrusion. This innovative product consists of an aqueous dispersion containing solid polymer particles and surfactants, effectively blocking gas migration into the cement slurry during its critical hydration phase. In addition to enhancing the cement bond with casing and formation interfaces to control gas migration, the D620 GASBLOK additive also creates a thin, low-permeability filtercake that minimizes fluid loss from the cement slurry.

Typical bottomhole circulating temperature (BHCT) range for this additive is from 150 to 300 degF [66 to 149 degC]. Temperature extensions are possible with laboratory testing to ensure the slurry meets the required properties. D620 GASBLOK additive can be used in slurries with density ranges from 8 to 23 lbm/galUS [960 to 2,760 kg/m³].

• Primary and remedial cementing
• Wells with a narrow window between pore and fracture pressure
• Freshwater or seawater applications
• Typical BHCTs from 150 to 300 degF [66 to 149 degC], with extension possible with laboratory testing
• Slurries with densities ranging from 8 to 23 lbm/galUS [960 to 2,760 kg/m³]

• Easy to place in narrow annular clearances
• Easy to mix and pump with standard field equipment

• Compatible with CemCRETE™ concrete-based cementing technology, FlexSTONE™ advanced flexible cement technology, CemFIT™ adaptive cement systems, and standard SLB cement additives
• Provides low slurry rheologies, enabling low friction pressures during the cement job
• Forms a low-permeability plastic film to prevent gas movement
• Improves cement bonding to formation and casing
• Excellent fluid loss control

The dispersed polymer particles block the pore spaces between the cement grains, reducing the slurry permeability and restricting movement of gas through the matrix. When formation gas enters the cement slurry due to a drop in hydrostatic pressure, the latex particles coalesce to form a coherent, low-permeability plastic film in the pore spaces between the cement grains that blocks further migration into the cement.