POLYPAC ELV Extralow-Viscosity Polyanionic Cellulose Additive | Schlumberger

POLYPAC ELV

Extralow-viscosity polyanionic cellulose additive

POLYPAC ELV low-viscosity polyanionic cellulosic polymer (PAC) additive is used primarily as a fluid-loss reducer. This high-performance product readily disperses in water-based drilling fluids ranging from fresh to saturated salt water. POLYPAC ELV additive is primarily used in weighted systems to avoid an uncontrollable viscosity buildup.

Typical Physical Properties
Physical appearance Free flowing, white powder
Specific gravity 1.5–1.6
pH (1% solution) 6.0–8.5
Solubility Soluble in fresh water to saturated brines

Applications

POLYPAC ELV additive is used to control fluid loss in freshwater, seawater, salt, and KCl drilling fluids while providing supplemental shale inhibition and lubricity. It forms a thin, resilient low-permeability filtercake that minimizes the potential for differential sticking.

Because of its extremely low viscosity, POLYPAC ELV additive can be used at higher concentrations than POLYPAC UL polymer to provide additional benefits in HPHT fluid-loss control, shale control, and lubricity with minimal viscosity increase. This allows systems that depend solely on POLYPAC ELV additive to tolerate higher levels of low-gravity solids (LGS).

The properties of the POLYPAC ELV additive make it ideally suited for drilling high-angle, extended-reach wells through reactive shales, particularly when combined with a highly shear-thinning rheology control polymer, such as DUO-VIS polymer. POLYPAC ELV additive is the preferred fluid loss agent for the GLYDRIL system as well as in other nondispersed drilling fluid systems such as POLY-PLUS systems and saturated salt systems.

POLYPAC ELV additive resists bacterial attack and does not require a biocide or preservative.

In freshwater fluids, normal concentrations range from 0.53 to 5.1 lbm/bbl [1.5 to 14.5 kg/m3]. In seawater and saltwater systems, concentrations will range from 2.1 to 6.0 lbm/bbl [6 to 17 kg/m3] to realize maximum benefit for fluid loss, shale inhibition, and lubricity.

Advantages

  • Excellent fluid-loss additive and filtercake quality enhancer for use in nondispersed systems
  • Provides shale control and lubricity with minimal viscosity increase
  • Resists bacterial attack; no biocide or preservative is needed
  • Suitable for extended reach drilling and deepwater drilling when used in combination with DUO-VIS polymer
  • Effective across a wide pH range

Limitations

  • Circulating temperature stability of approximately 300 degF [149 degC]
  • Effective in systems with total hardness level <1,000 mg/L (as calcium), but can be precipitated in conditions of high hardness and high pH

Toxicity and handling

Bioassay information is available upon request. Handle as an industrial chemical, wearing protective equipment and observing the precautions as described in the safety data sheet.

Packaging and storage

POLYPAC ELV additive is packaged in 50-lbm [22.7-kg] multiwall paper sacks. Store in a dry location away from sources of heat or ignition, and minimize dust.

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