CONQOR 404 WH Phosphate-Based Corrosion Inhibitor | SLB


Phosphate-based corrosion inhibitor

Schlumberger Oilfield Services
Schlumberger Oilfield Services

CONQOR 404 WH corrosion inhibitor is an all-purpose, water-soluble organophosphate compound used to prevent corrosion on metal surfaces.


CONQOR 404 WH inhibitor is used as a corrosion inhibitor in all water-based drilling fluids; brine water systems; and air, mist, or foam fluids. CONQOR 404 WH additive at relatively low concentrations is particularly effective against oxygen corrosion in aerated muds used in underbalanced drilling operations and low-solids nondispersed water-based fluids.

Typical recommended treatment of CONQOR 404 WH inhibitor is 2–4 galUS for every 100 bbl [0.5–1.0 L/m3] of makeup fluid depending on anticipated conditions, other chemicals used in the system, and the corrosive environment—i.e., salinity, pH, temperature, oxygen content, and acid gasses. If the corrosion rate is unacceptably high, the concentration should be increased to at least 7 galUS/100 bbl [1.7 L/m3]. For aerated systems, an initial treatment of 12 galUS/100 bbl [2.9 L/m3] is recommended. The product should be evenly dispersed throughout the circulating mud system and can be added either through the chemical barrel or directly to the mud pits wherever good agitation occurs.

The corrosion rates should be monitored at all times either directly or with corrosion coupons and treatments should be adjusted according to their analysis. A good corrosion-control program includes a thorough makeup-water analysis, chemical treatments for corrosive contaminants, and an adequate bacterial control for systems that contain biodegradable additives.

Typical physical properties

  • Physical appearance: Clear yellow liquid
  • Specific gravity: 1.40–1.50
  • Pour point: –10 degF [–23 degC]


  • Compatible with anionic foamers
  • Highly effective against oxygen corrosion caused by dissolved oxygen
  • Low toxicity
  • Minimum impact on fluids rheology
  • Effective in fresh to saturated salt water
  • Effective in aerated fluids such as those used in air-drilling operations
  • Effective to temperatures in excess of 350 degF
  • Does not require an oxygen scavenger