BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
System Preparation
Table 3-21 Range of Glycol Cloud Points in KCl and NaCl Brines is a compilation of various
brine and glycol cloud points. It can be used for planning purposes in lieu of the software
program, GLY-CAD ® . However, the final system formulation should be prepared from GLY-
CAD.
Table 3-21
Range of Glycol Cloud Points in KCl and NaCl Brines
Product Brine Salt, % CPT, °F
AQUA-COL, 1 – 10% by wt. KCl 5 - 20 42 - 130
AQUA-COL, 1 – 10% by wt. NaCl 5 – 26 25 - 124
AQUA-COL B, 1 – 10% by wt. KCl 5 – 20 104 - 241
AQUA-COL B, 1 – 10% by wt. NaCl 5 – 26 62 - 225
AQUA-COL D, 1 – 10% by wt. KCl 5 – 20 92 - 242
AQUA-COL D, 1 – 10% by wt, NaCl 5 – 26 74 - 425
AQUA-COL S, 1 – 10% by wt. KCl 15 – 20 195 – 286
AQUA-COL S, 1 – 10% by wt, NaCl 15 – 26 146 - 262
Cloud Point Maintenance Offshore
Under normal drilling, there will be a temperature differential between BHCT and formation
temperature. To achieve the maximum performance from cloud point glycols, it is desirable to
maintain the cloud point within this range as close as possible. This requires that glycols are
available so that any cloud point can be achieved between approximately 30°C (86°F) and 75°C
(167°F). The lower end of this range (30°-40°C [86°-104°F]) can be readily achieved with
AQUA-COL in the 2% to 3% range and KCl levels of 15 to 30 lbm/bbl. The higher end (55°C to
75°C (131°F to 167°F) can also be achieved by utilizing AQUA-COL D at 3% to 5% together
with higher levels of KCl.
Note:
All references to percentages of glycol in fluid should be interpreted to relate to the glycol
as a percentage of the brine phase of the fluid. Adding 30 bbls glycol to 970 bbls fluid will
only result in 3% glycol concentration if the fluid is completely unweighted and devoid of
drill solids. In all other cases, the solids volume of the fluid should be backed out of any
calculations relating to volume percentages of glycols.
Rheological Properties
The following ranges for gel strengths and yield points are recommended when drilling at rates of
100 – 200 ft/hr in the indicated hole sizes.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 3-79