M-I PAC UL Ultralow-Viscosity Filtration-Control Additive | SLB


Technical-grade ultralow-viscosity polyanionic-cellulose filtration-control additive

Schlumberger Oilfield Services

M-I PAC UL additive is designed for situations where filtration control is needed with only minimal increases in rheology. M-I PAC UL additive will perform well in all brine applications, especially saltwater-based fluids. M-I PAC UL additive can be used at all densities in either dispersed or nondispersed systems. M-I PAC UL polymer will encapsulate solids to control dispersion of active shale.

Typical Physical Properties
Physical appearance Cream-colored, free flowing powder
Specific gravity 1.5–1.8
pH 6.5–8.0


M-I PAC UL additive controls fluid loss in freshwater, seawater, KCl, and salt water. M-I PAC UL additive aids in the formation of a tough, thin filtercake to minimize the potential for differential sticking.

Recommended treatment for M-I PAC UL polymer is from 0.5 to 3.0 lbm/bbl [1.5 to 9.0 kg/m3] depending on the water type and the salt level to control fluid loss.

A concentration of 2.5 lbm/bbl [7 kg/m3] of M-I PAC UL additive in fresh water will provide a viscosity of 15 cP and only a 5-lbm/100 ft2 [2.5-Pa] yield-point value.

M-I PAC UL additive will create an envelope around exposed shales and cuttings for encapsulation that reduces dispersion and improves wellbore integrity. Encapsulation protects the shale from exposure to water that tends to destabilize the shale.


  • Effective in controlling filtration with minimal increase in rheology
  • Functions at all pH ranges
  • Environmentally acceptable
  • Resists bacterial attack, requiring no biocides or preservatives
  • Performs in a wide variety of waters


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

M-I PAC UL additive is packaged in 55-lbm [25-kg] multiwall paper sacks. Store in a dry location away from sources of heat or ignition, and minimize dust.