DRILZONE

ROP-enhancing antiaccretion additive

DRILZONE ROP-enhancing antiaccretion additive is specifically designed to improve the rate of penetration (ROP) in water-based mud (WBM) systems, especially when run with polycrystalline diamond compact (PDC) bits.

DRILZONE additive uses a special blend of surface-active agents to keep the bit free of solids. The chemical makeup of the DRILZONE additive assists in removing 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 bottomhole assembly (BHA) balling, but also lowers torque and drag.

Applications

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

For ROP enhancement, 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 rate, and ROP.

Typically, addition rates may range from 15 to 30 galUS [57 to 114 L] per hour 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.

Advantages

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
Does not induce foaming or aeration of the mud system

Limitations

High-solids and weighted fluids above 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.