BAKER HUGHES - Drilling Fluids Reference Manual

BOREHOLE PROBLEMS
OMNI-LUBE is an environmentally acceptable polymeric fatty acid solution which will
effectively reduce torque and drag in most emulsion-based drilling fluids. Results obtained from
field tests of OMNI-LUBE indicate that friction can be lowered by up to 25% as compared to
untreated fluids, and torque is less erratic.
LC-LUBE is chemically inert, sized graphite which can be used effectively as a general borehole
lubricant. It is environmentally acceptable and is applicable in water-, synthetic-, or oil-based
fluids. LC-LUBE can also be effective in reducing the probability of stuck pipe. It has little
effect on the rheological properties of drilling fluid. It has high compressive strength and because
of its excellent bridging properties, it is also used to control loss of circulation (partial and
seepage losses) in drilling fluids.
LC-GLIDE is a spherical, synthetic-graphite product used for torque and drag reduction during
drilling, wireline and casing running operations. Its spherical shape provides a high performance
alternative to glass and copolymer beads typically used for torque and drag reduction. It has an
advantage over the beads in that when it is crushed it becomes graphite particles which still have
lubricious properties, whereas when the beads are crushed the resultant particles are not
lubricious.
LUBE-622 is a non-toxic, biodegradable lubricant which can be used effectively in salt based
systems.
MIL-GRAPHITE is environmentally acceptable graded graphite used primarily to enhance
lubricity and sliding and is applicable in water, synthetic, or oil-based fluids.
The PENETREX ® family of products is designed to reduce bit-balling and improve penetration
rates in water-based systems up to 400% over untreated systems. Products making up this family
are: PENETREX for offshore operations, PENETREX L for land operations, and PENETREX
NS, for North Sea applications.
HIGH BOTTOM HOLE TEMPERATURES
Mechanisms of Thermal Degradation
From the drilling fluid point of view high temperatures can be considered as those above which
conventional drilling fluid additives begin to thermally degrade at an appreciable rate. The
degradation leads to loss of product function, and system maintenance becomes difficult and
expensive. The majority of drilling fluid treatment chemicals derived from natural products begin
to degrade at temperatures between 250 and 275°F. However, many systems designed for hot
wells are based on clay and contain lignosulphonates and ignites and can exhibit temperature
stability up to approximately 350°F. However, management of these drilling fluids above 300°F
can be difficult and expensive.
Thermal degradation can be simplistically thought of as the result of putting so much energy into
a chemical substance that some portion of its structure can break off or change form. Similar
results can be effected at lower temperatures by the presence of certain chemicals. Oxygen (from
air) can promote oxidation; water (present in the drilling fluid) can promote hydrolysis. Whatever
the cause, or particular chemical reaction involved, the end result is that at higher temperatures
formerly stable drilling fluids become difficult to control. Unfortunately elevated temperatures
are usually not the only stresses experienced by drilling fluids in high BHT wells. Often chemical
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 7-45