BAKER HUGHES - Drilling Fluids Reference Manual

RESERVOIR APPLICATION FLUIDS
CLEAR-DRILL K (potassium formate) is a crystalline white powder, highly soluble in water
giving mildly alkaline brines up to a density of 1.58 S.G. (13.2 ppg) The product can also be
supplied as a concentrated brine.
• System applicability: CLEAR-DRILL K.
• Temperature limitations: Stable at 250°C (482°F)
CLEAR-DRILL ® C
CLEAR-DRILL C (cesium formate) is a crystalline white powder, highly soluble in water giving
alkaline brines up to a density of 2.35 S.G.(19.6 ppb). It is commercially available.
• System applicability: CLEAR-DRILL C
• Temperature limitations: Stable at 250°C (482°F)
Weighting Materials in CLEAR-DRILL ® Brines
Conventional weighting materials can be used in CLEAR-DRILL brines to provide fluids above
the normal density ranges available for the solids-free systems with the exception of barite in
CLEAR-DRILL K solutions with densities above 1.30 SG (10.8 ppg, 45% by weight). Calcium
carbonate, hematite (DENSIMIX), and manganese tetraoxide (MICROMAX) can all be utilized.
High concentrations of CLEAR-DRILL K (i.e. above 1.50 S.G. (12.5 ppg)) result in the partial
solubilization of barium sulphate to provide levels of soluble barium up to 2,000 mg/l, depending
on time of exposure, temperature and barite availability. This phenomenon has not been observed
in lower density CLEAR-DRILL K solutions, or in other formate solutions even at saturation.
Products Used in CLEAR-DRILL Fluids
XAN-PLEX ® D / Xanthan Gum Polymer
XAN-PLEX D Polymer is the primary viscosifier for all systems where temperatures are not
expected to exceed 150°C (302°F). These polymers provide the best rheological profile of any
commonly available polymer and result in shear-thinning fluids under dynamic flow with good gel
structures under static conditions. In addition, there is a marked degree of synergy between xanthan
polymers and concentrated formate solutions which results in a demonstrable increase in the upper
temperature limit for these products.
• System applicability: ALL
• Temperature limitations: Up to 150°C (302°F)
KEM-SEAL ®
KEM-SEAL is a synthetic copolymer of AMPS and alkylacrylamide and has proven thermal
stability to temperatures in excess of 250°C (482°F). KEM-SEAL also provides filtration control
under high temperature conditions and is resistant to most types of contamination.
• System applicability: ALL
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 6-32