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APPICATIONS
Mud system. COATER is a high-molecular-weight, anionic liquid polymer.
The molecular weight is between 10 million to 15 million. It is
a excellent additive for mud to provide cuttings encapsulation and
shale stabilization. COATER also acts as a viscosifier, friction
reducer. It can be used in drilling fluids ranging from low(non)-solids
to weighted, utilizing makeup waters from fresh to saltwater. Typical
concentration of COATER are 1 to 4kg/m3. The main function of it
is to provide cuttings encapsulation, you can get a better wall
of the hole if some KCL would be used in the mud. A higher concentration
would be required in salt mud.
Solids-free fluids. COATER can be used in clear-water , solids-free
drilling fluids. It increases mud viscosity and enhances solids
removal by flocculating the undesired solids. It also provides cuttings
encapsulation and improved wellbore stability. The system is frequently
used in slim hole continuous-coring application. The addition of
1 to 4kg/m3 enhances solids removal by flocculating solids. Usually,
the value of MBT may be lower than 25g/l if keeping concentration
of COATER more than 3kg/m3 in the mud.
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Typical Properties
of COATER in freshwater
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Concentration(kg/m3)
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PV(cp)
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YP(1b/100ft2)
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M.F.(sec/qt)
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1
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2
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2
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30
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2
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3
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3
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32
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3
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4
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4
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34
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4
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5
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5
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36
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Low-Solids, Non-Dispersed muds COATER is well suited to
this mud system. In reduced-bentonite muds, COATER serves as a bentonite
extender to increase viscosity, flocculates drill solids for more
efficient removal, encapsulates cuttings and improves wellbore stability.
Weighted muds. COATER can be used in weighted muds for
cuttings encapsulation, improved wellbore stability. Secondary viscosity,
and to improve filter cake integrity. The effectiveness of the polymer
is reduced as the polymer is reduced as the concentration of organic
anionic dispersants increases.
PHYSICAL PROPERTIES
| Physical appearance |
Light yellow opaque liquid
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| Specific gravity |
1.05-1.10
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| Flash point |
 90  |
| Pour point |
 -20 |
| PH(1%solution) |
6-8
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| Viscosity(1%solution) |
35cp |
METHOD OF ADDITION
COATER may be mixed into the active mud system or premixed at higher
concentrations in a separate pit or chemical barrel, then blended
into active system. It can be poured directly into the pits at any
point where good agitation exists such as over a mixer or added
through the mixing hopper or chemical barrel. A small, steady stream
of COATER injected into the flowline will provide selective flocculation
of drill solids. Caustic and lime should not be mixed at the same
time as COATER.
Sweeps may be accomplished by mixing COATER directly in the active
system at the suction pit or by pouring 3-4 liter directly into
the drillstring during connections.
ADVANTAGES
a. Provides excellent cutting encapsulation and limits cutting
dispersion.
b. Provides improved shale stabilization.
c. Enhances the removed of drill solids.
d. Aids in preventing balling on the bit, stabilizers and
bottomhole assembly by coating and lubricating solids.
e. Liquid product for easy mixing and rapid yield.
f. Improves the lubricity of most mud systems, particularly
non-dispersed muds, when used in combination with a lubricantes.
g. Low pour point less then -20
for easy use in cold climates.
h. Can be used to viscosify clear-water and low-solids drilling
fluids.
LIMITATIONS
The following limitations apply to all acrylamide/acrylate copolymers:
a. During initial treatment with COATER in a non-dispersed
mud system, severe flocculation may occur, causing high viscosity
until all of the solids are coated. Continued addition of COATER
results in a stable system with desired rheology.
b. COATER is calcium-sensitive and begins to precipitate
when the calcium concentration exceeds 300 mg/l.
c. COATER is pH-sensitive, with an optimum range of 8.5 to
10.5 . At pH level above this rang, hydrolysis may convert polyacrylamide
into polyacrylate and release ammonia (NH3).
d. COATER is temperature-stable to approximately 180
although the copolymer may begin to hydrolyze into polyacrylate
when exposed to prolonged temperature above 135
and release ammonia (NH3).
e. COATER is subject to shear degradation of its viscosity
and may eventually lose the ability to viscosity, but cuttings encapsulation
and shale stabilization will not be affected.
PACKAGING AND STORAGE
COATER is packaged in 25 kg or 50 kg, plastic cans.
Keep containers sealed and do not allow water to contaminate COATER
containers. Store in a well-ventilated area away sources of heat
or ignition.
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