DRILZONE ROP-Enhancing Antiaccretion Additive | Schlumberger


ROP-enhancing antiaccretion additive

DRILZONE additive is specifically designed to improve ROP in water-based drilling fluids, especially when run with PDC bits.

Employing a special blend of surface-active agents to keep the bit free of solids, DRILZONE additive helps remove any buildup of drill solids below the bit, allowing the cutters to make continuous contact with new formation. DRILZONE additive not only reduces bit and BHA balling but also lowers torque and drag.

Typical Physical Properties  
Physical appearance Yellow to brown liquid
Odor Very mild hydrocarbon
Specific gravity 0.78 – 0.85
Solubility in water Insoluble
Flash point >201 degF [>94 degC] (Setaflash closed cup)


DRILZONE additive is designed to enhance the ROP performance of water-base mud systems. It is especially applicable when drilling medium-to-hard shales in both onshore and offshore operations.

For ROP enhancement, 1% to 2% by volume of the DRILZONE additive should be added directly to the mud system at or near the pump suction over one circulation period. Ideally, the initial treatment should be made prior to drilling out of the casing shoe or after a trip before entering the hole while the bit and BHA are clean. After the initial treatment, the product should be continually added or injected into the mud stream at the pump suction while the bit is drilling. The injection rate will vary according to hole size, pump rate, dilution rates, and ROP.

Typically, addition rates may range from 15–30 galUS/h [57–114 L/h] of drilling. An injection pump attached to the low-pressure side of the mud pump helps control addition rates precisely. DRILZONE additive concentrations of up to 5% to 7% by volume will not affect drilling fluid properties or environmental toxicity.


  • Effectively increases ROP while drilling all shales
  • Improves bit life, reducing the number of trips
  • Reduces torque and drag
  • Improves mud filtercake quality and lowers fluid-loss values
  • Works well with high-performance PDC bits
  • Contains surface-active, metal-wetting agents that reduce the potential for bit and BHA balling
  • Will not induce foaming or aeration of the mud system


  • High-solids and weighted fluids above 14 lbm/galUS [1,678 kg/m3] may develop slightly higher viscosities and gels.
  • Optimum performance may not be realized if the material is not added continuously in sufficient concentration while drilling.
  • Some mud fluorescence may be noted at high product concentrations
  • Some materials containing gilsonite or asphalts may partially solubilize in the presence of the DRILZONE additive, which may promote sheening of offshore discharges.

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

DRILZONE additive is packaged in 55-galUS [208-L] drums and is available in bulk.

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