BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
Deflocculating Agents
ALL-TEMP ® − Water-base deflocculant/rheological properties stabilizer with special
applications in high temperature environments.
NEW-THIN TM – low molecular weight polyacrylate polymer dispersed in water. Effective
thinner in low-weight, low-solids systems. Contains no chrome or heavy metals. Hardness levels
should be less than 500 mg for optimum thinning, the lower the hardness the more efficient the
viscosity reduction.
UNI-CAL ® – lignosulfonate used as a supplemental thinner if solids overload the system.
Treatment and Control Techniques for NEW-DRILL Systems
The composition and properties of drilling fluids are greatly affected by the formation
contaminants encountered while drilling. Selected drilling fluid components are added to negate
a contaminant or potential contaminant. In order to limit the scope of discussion the following
common contaminants will be discussed:
• Salt and salt water flows
• Calcium or magnesium
• Cement
• Carbonates
• Temperature
• Dispersible Cuttings
The problem of solids contamination will be considered in Chapter 4, Contamination of Water-
Base Fluids. It should be emphasized, however, that the problems associated with all of the
above mentioned contaminants will be magnified by the presence of solids. In all cases, limit the
amount of undesirable reactive solids, i.e., drilled solids, should be kept to the lowest practical
level.
Salt Contamination
Source
Salt may come from make-up water, salt stringers, massive salt sections, salt water flows, and
commercial sources. Regardless of the source it has an impact on drilling fluid properties and
chemical selection.
Since salt cannot be precipitated by chemical means, the only method of reducing salt
concentration is through dilution. This will also help to reduce the problems caused from
flocculation of clay solids by reducing the concentration of the solids in the fluid. If dilution is
not possible due to density requirements or water availability, then treatment with chemicals may
be necessary.
Deflocculation – If chloride levels remain below 30,000 mg/L, then NEW-THIN can be used to
reduce yield point and gel strength. Other deflocculants such as UNI-CAL can be used, but it
may be necessary to increase the pH to 9.5 for this product to be effective. The dispersion of
drilled solids can also result from the addition of a lignosulfonate and caustic to the NEW-DRILL
system. Because of these two factors, treatment with organic thinners is not recommended unless
viscosity reductions are not satisfactory using NEW-THIN.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 3-55