BAKER HUGHES - Drilling Fluids Reference Manual

BOREHOLE PROBLEMS
Spotting Fluids
Baker Hughes Drilling Fluids offers a variety of spotting fluids which are designed for use in
every drilling environment. These spotting fluids may be used in either weighted or un-weighted
systems.
• BLACK MAGIC ® – a compound with a premium-grade, high melting point asphalt in
diesel oil. Barite is added at the rigsite to the liquid solution.
• BLACK MAGIC ® LT – contains a premium-grade asphalt compounded in a low-toxicity
mineral oil. Barite is added at the rigsite to this liquid solution.
• BLACK MAGIC ® SFT ® – (Sacked Fishing Tools) is a dry mixture of optimum size air-blown
asphalt, lime, fatty acids, and dispersants in a powdered form. This sack product is stored at the
rigsite and mixed with low-toxicity mineral oil, #2 diesel, or synthetic fluids.
• BIO-SPOT ® – a non-toxic, oil free, water soluble spotting fluid concentrate. BIO-SPOT ® can
be mixed rapidly and contributes virtually no toxicity to water-base fluid systems. BIO-SPOT
is recommended for use when the use of oil and toxic surfactant blends are undesirable.
• MIL-SPOT TM 2 – a liquid blend of a long chain fatty acid pitch, an emulsifier, and gellant.
MIL-SPOT 2 can be used in #2 diesel, low-toxic mineral oils or synthetic fluids.
• MIL-FREE - a liquid concentrate containing a long-chain fatty acid compound reacted with a
surfactant. Can be used with any base oil and is recommended for freeing differentially stuck
pipe in water-base drilling fluids when an un-weighted spotting fluid can be safely used.
Spotting Fluid Placement
The success of spotting fluids frequently depends upon time elapsed between sticking and
placement of the spotting fluid. If the spotting fluid can be placed adjacent to the area of sticking
within half an hour, the pipe may come free within one to two hours. If several hours have
elapsed prior to placement of spotting fluid, 10 to 15 hours may be required for the pipe to come
free. For this reason, spotting fluid materials should be kept on the rig and mixing facilities
should be available to facilitate prompt placement.
Even with prompt placement, it is essential that the spotting fluid is placed in the zone of sticking
and that the fluid does not migrate too rapidly. When spotting diesel oil and MIL-FREE ® in lowdensity
fluids, it would be advisable to calculate annular volume around drill collars and double
this calculated quantity. This extra volume will compensate for hole enlargement. It will also
allow a slight under displacement of drillpipe so that 1 to 2 bbl/hr of solution can be pumped to
compensate for migration.
When stuck pipe occurs with weighted fluids, a spotting fluid should be used with a density equal
to or slightly higher than the drilling fluid in the annulus to avoid migration. Time elapsed
between sticking the pipe and placement of the spotting fluid has such a drastic effect on the
ability of the spotting fluid to free the pipe that consideration should be given to spotting an unweighted
pill if possible.
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 7-36