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Mud-System: COATER (equivalent to POLYPLUS of M-I) is a high-molecular-weight, anionic liquid polymer. The molecular weight is between 10 million to 15 million. It is an 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 (none)-solids to weighted, utilizing makeup waters from fresh to salt water. Typical concentration of COATER is 1 to 4kg/m3. The main function of it is to provide cuttings encapsulation, and 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 borehole 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.
| Typical Properties of COATER in freshwater | |||
|
Concentration(kg/m3) |
PV(cp) |
YP(1b/100ft2) |
M.F.(sec/qt) |
|
1 |
2 |
2 |
30 |
|
2 |
3 |
3 |
32 |
|
3 |
4 |
4 |
34 |
|
4 |
5 |
5 |
36 |
Low-Solids, Non-Dispersed Mud: COATER is well suited to this type of mud system. In reduced-bentonite mud system, COATER serves as a bentonite extender to increase viscosity, flocculate drill solids for more efficient removal, encapsulate cuttings and improve wellbore stability.
Weighted Mud: COATER can be used in weighted mud for cuttings encapsulation and improving wellbore stability. It is functioned as the secondary viscosity, and to improve filter cake integrity. The effectiveness of the polymer is reduced since the polymer is reduced as the concentration of organic anionic dispersants increases.
Physical Properties:
|
Physical appearance |
Light yellow opaque liquid |
|
Specific gravity |
1.05-1.10 |
|
Flash point |
≥90℃ |
|
Pour point |
≤-20℃ |
| PH (1%solution) | 6-8 |
| Intrinsic viscosity (dL/g) | ≥11 |
