BAKER HUGHES - Drilling Fluids Reference Manual

BOREHOLE PROBLEMS
Drilling Fluid Products
Generic Type Temp Limit °F Temp Limit °C
Guar Gum
Starch
Biopolymers
HT Starch
CMC and PAC
Lignosulphonate
Standard Lignite
Modified Lignite
Synthetic Polymers
225
250
250 – 275
275
275
250 – 325
300 – 350
350 – 450
400 - 500
107
120
120 – 135
135
135
120 – 160
150 – 175
175 – 230
205 - 260
Table 7 - 11 Drilling Fluids Products Temperature Limitations
Drilling Fluid Systems
Generic Type Temp Limit °F Temp Limit °C
Non Dispersed Polymer
NDP – High Temperature Formulation
Bentonite/FCL
Bentonite/FCL/Lignite
Bentonite/Modified Lignite/polymer Blends
Synthetic Polymers (PHPA, PA, SSMA, VSA, etc.)
275
350
300
350
400
400 - 500
Table 7 - 12 Drilling Fluids Systems Temperature Limitations
135
175
150
175
205
205 - 260
Extending Temperature Limits
To increase the temperature stability of drilling fluids products and systems it is necessary to
inhibit the mechanisms that cause product failure and/or to substitute parts of a system that are the
first to lose product function.
The life of polymers can be extended by minimizing the reactions that cause severing of the
polymer chains. Primarily these reactions are hydrolysis and oxidation. Hydrolysis can be
minimized by maintaining a pH in the range 9.5 – 10.5 and oxidation can be avoided by the use
of an oxygen scavenger. This approach alone will extend the thermal stability of most systems by
approximately 25°F. Some heavy metals are believed to catalyze the breakdown reactions and
products are available that “mop up” these elements. When polymers are used in formate brines
their thermal stability is increased by as much as 50°F. This is largely due to the formate brines
being powerful antioxidants.
Drilling Fluid Properties
Both temperature and pressure can have significant effects on drilling fluid properties.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 7-47