BAKER HUGHES - Drilling Fluids Reference Manual

CORROSION
Corrosivity of Drilling Environment
Initial Treatment,
gal/100 bbl fluid
KD-700, ppm
in mud filtrate
KD-40
Table 8- 4
Low 5 250
Moderate 10 450
Severe 15 850
KD-700 Treatment Levels in Water-Based Drilling Fluids
KD-40 is a water soluble corrosion inhibitor designed to prevent oxygen related corrosion in
water-based drilling fluids, aerated drilling fluids and in mist and foam drilling applications. KD-
40 is an organophosphate formulation that forms a strong, protective film on metal surfaces. KD-
40 has little or no effect on fluid rheological properties and is effective in fresh water and brine
water systems under 400 ppm Ca +2 or Mg +2 . KD-40 prevents oxygen related corrosion and is
effective against acid gas corrosion. KD-40 is effective to 400°F. KD-40 disperses readily in
drilling fluids and should be added through the mud hopper or chemical barrel. Treatment rates
depend on the corrosivity of the drilling environment. Residual levels of KD-40 can be
determined with an organophosphate analytical test kit.
Corrosivity of Drilling Environment
Initial Treatment,
gal/100 bbl fluid
KD-40, ppm in mud filtrate
Low to Moderate 2 - 5 150 - 300
Table 8- 5
Scale Inhibitor
SCALE-BAN
Severe 7 - 12 450 – 700
KD-40 Treatment Levels in Water-Based Drilling Fluids
SCALE-BAN is a chemical inhibitor that interrupts and deforms the normal crystalline growth
pattern of carbonate scales. SCALE-BAN is required in very low concentrations; as little as 3 to
5 ppm in the system is effective at inhibiting scale formation. Visual inspection of the drillpipe will
indicate if treatment levels are sufficient.
When scale is formed, oxygen concentration cells develop beneath the scale, and severe localized
pitting develops. SCALE-BAN is suggested anytime carbonate gas may be present or when lime
is used in significant quantities in the circulating system. Where scale deposits are already present
on the pipe, sandblasting or other cleaning is required to remove the scale. SCALE-BAN will
not remove existing scale from the pipe.
PACKER FLUID TREATMENT
Packer fluids are fluids left between casing and tubing. Casing packs are fluids left between casing
and open hole. While these fluids may be left in place for a variety of reasons, the principal reasons
BAKER HUGHES DRILLING FLUIDS
REVISION 2006 8-12
REFERENCE MANUAL