BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
6. Filtration control in the range of 15 to 20 cc can be achieved with MIL-PAC. For further
filtration control, it may be necessary to add MILSTARCH or BIO-LOSE or BIO-PAQ in
a 2:1 ratio.
7. Remember that NEW-DRILL encapsulates solids and cuttings discarded and is also
discarded from the system. Therefore, it is recommended that NEW-DRILL be added at
0.15 lbm/bbl for each barrel of drill water added. Also add 0.5 to 3.0 lbm/bbl to new mud
volume built. This usually equates to about 5 to 7 lb of NEW-DRILL for each barrel of
formation solids drilled up and discarded. This treatment will vary widely depending on
activity of formation being drilled.
Typical properties for this type system are,
• Density (lbm/gal) – 8.8 to 9.2
• PV (cP) – 4 to 6
• YP (lbf/100 ft²)– 25 to 45
• Gels(lbf/100 ft²)– 23/26 (high, but fragile)
• API fluid loss – 15 to 35 cc/30 min
• pH – 8.5 to 10.0
• Low gravity solids (LGS) content - 3 to 5% with 5% being the maximum
Much of the success achieved in stabilizing reactive clays with this fluid has resulted from
awareness and control of mechanical factors, combined with inhibitive characteristics of
potassium fluids. It is a good practice, therefore, to maintain laminar flow in the annulus while
drilling and minimize swab and surge pressures to reduce mechanical aggravation of sloughing
shales.
Additives for Control and Maintenance of Properties
Electrolytes
NEW-DRILL ® is compatible with all concentrations up to and including saturated sodium
chloride (NaCl). Viscosity decreases with increased concentration of electrolyte.
NEW-DRILL ® systems have been run at concentrations of KCl up to 18% by weight.
NEW-DRILL ® is compatible with a seawater environment although hardness of the system
should be treated downwards with caustic soda.
Alkalinity Control
NaOH (caustic soda) – most common alkalinity and pH control product.
KOH (caustic potash) – has been used frequently. Requires about 40% by weight more than
NaOH to achieve an equivalent pH.
Lime & gypsum – used almost exclusively to treat alkalinity imbalances due to carbonates when
in a reactive or ionic state. Carbonates reduce the inhibitive properties of the polymers.
Fluid Loss Control Agents
BIO-LOSE ® – acceptable in low pH seawater system. At low pH, some preservative may be
needed.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 3-53