Casing Equipment Catalog Sec 13_Foam Wiping ... - Halliburton

When to Use the CST Tool
• The CST tool can be used for any off-bottom
plugging operations as long as there is no loss
circulation problem below the tool.
• It can be used in hole sizes up to 45-in. ID.
• It can be placed through restrictions of 2-, 2 1/2-,
and 4-in. ID.
• Inclination from 0° to horizontal and higher if
required.
• No hydrostatic pressure limitation.
• Compatible with all known drilling fluids.
When Not to Use the CST Tool
• When fluid losses below the point where the CST
tool will be placed are experienced.
• If hole size is believed to be larger than 45 in. or
highly irregular, washed out, etc.
• If the whole plug length is to be drilled out (i.e.,
setting the whole cement plug inside casing)
including the CST tool, then special precautions
should be made regarding bit selection.
HAL25018
Optional CST
Plug Setting Diverter
• When there is a combination of 3 1/2-in. drillpipe (DP)
and 6 5/8-in. DP in the same string, a non-standard dart
with a wider working range must be used.
CST transport tube
with CST tool
Drillpipe
Push rod
CST transport tube
Drillpipe
Drillpipe
Rig Floor
Drillpipe
Rig Floor
Cement
Cement
Dart
CST tool
CST tool
CST tool
Figure 1 Figure 2
Figure 3
Figure 4
Figure 1 – Transport Tube Temporarily Installed Inside Drillpipe.
Figure 2 – CST Tool Pushed into Drillpipe from Transport Tool, then Transport Tool Removed.
Figure 3 – CST Tool Circulated into Place ahead of Cement.
Figure 4 – With the CST Tool in Place, Cement can be Placed with a Higher Probability of the Plug Avoiding Contamination or being Disturbed during Initial Set Time.
Plug Setting Aids 13-4