BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
• The bentonite content (via MBT) of the system should be less than10 lbm/bbl before adding
MAX-GUARD. If not, then clay flocculation will occur as this product reacts with the
reactive clays in the system. This will also consume (deplete) the concentration of MAX-
GUARD in the system and require that additional product be added to have excess material
available when drilling begins.
• NEW-DRILL LV, L or PLUS should be added at concentrations up to a 1.0 lbm/bbl in a
freshwater premix, preferably using a shear device. Do not add NEW-DRILL products in
pre-mix containing MAX-PLEX because prior work in field tests has indicated that blinding
and loss of MAX-PLEX material over shaker screens is increased.
• MILPAC LV can be added to the NEW-DRILL premix at concentrations up 1 lbm/bbl.
Seawater Systems
Seawater should be pretreated with caustic soda and soda ash to a pH of 10.5 and to precipitate
calcium and magnesium. MAX-PLEX should never be added directly to untreated seawater
because elements in seawater will react with and delete an important component of MAX-PLEX.
System Maintenance
pH
Deflocculants
Hardness levels
The minimum pH for PERFORMAX is pH 10.5. If the pH falls below this level,
then excessive depletion of MAX-PLEX will result. MAX-PLEX concentrations
should be carefully monitored, using the FSE method, when adding products that
cause pH to fall below minimum value. These include: LCM materials,
lignosulfonates, and lignite. Treat system with caustic soda prior to addition of these
materials to counter their pH-reduction effects. If PERFORMAX is subjected to
temperatures above 230°F, then monitor flowline pH at one to two hour intervals to
determine if pH reduction is occurring.
Deflocculants such as ALL-TEMP® can be used to control rheological properties.
However, such additives are acidic in nature and will reduce the pH of the system
causing a depletion of MAX-PLEX concentration (see pH statement above),
therefore treatment with caustic soda to adjust system pH to the proper level is
recommended prior to the addition of MAX-PLEX.
Soluble Ca+2 and Mg+2 will cause precipitation of a component in MAX-PLEX.
Total hardness should be below 400 mg/L before MAX-PLEX is added to the
system. Ideally, hardness will be below 100 mg/L. In some situations the presence
of aluminum compounds can interfere with total hardness and calcium
determinations. If indicator response is suspected, the use of a masking reagent
(triethanolamine or tetraethylenepentamine) is recommended.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 3-97