Underreamer
Techmaster Hydraulic PDC Underreamer is a hard wearing tool, used to enlarge the borehole beyond bit diameter. It can be opened and closed several times in downhole condition, making it the best choice for section enlarging jobs.
This simple and efficient arm design increases longevity and facilitates field maintenance.
The optimum mud ports placement also ensures thorough cleaning of the PDCs for faster reaming with less pack-off risks.
Description
Applications
- Remedial underreaming for running xpandable casing/liners.
- Section enlargement when diameter restriction is present.
- Gravel packing work-over.
- Wiping out bridges and key seats.
- Adequate annular space for cementing.
- Gravel packing for gas storage wells.
- Section enlarging or window opening job.
- Increasing Inflow diameter in Pay zone.
- Removing mud invaded zone at reservoir section
Features
- Integral stabilizer blades.
- No bearings, minimal moving parts (Ipiston, 3arms).
- Design selection of hole size and cutting types.
- Simple and effective arm design.
- Improved durability and field maintenance.
Shallow Test
- Connect the tool to the pilot assembly. Use the recommended torque for bottom thread. Note down the length between the bottom of the BHA and the arms; connect the top of the tool to the next BHA element using recommended torque for top thread. Connect the top drive or Kelly; lower the tool below the drill floor to prevent any mud spraying, while keeping the
- arms fully in view. Start the pumps at minimum flow and then increase the pump rate slowly, until the arms are fully open. Note the ecessary flow for full opening, and pressure drop if significant. Raise the tool back to the drill
- floor and check all arms are correctly closed. Tool is now ready to be run in
- hole.
Underreaming Operation
- PDC inserts are not suitable for casing milling. It is advised to start reaming a few meters below casing shoe. For the same reason,
- never circulate while moving the tool in casing.
- Before opening the arms, take neutral weight up/down and torque.
- Start circulating; start rotating and allow a few minutes without moving the tool for the arms to enter the formation; depending on arms size and section size check the torque before moving down.
- Start going down slowly, keeping minimum WOB and watching the torque to allow the arms to open fully. Do not apply full weight with arms partially open as it could seriously damage the arms.
- Once arms are fully open (check torque with arms closed and then open in a reamed section if necessary to confirm), more weight can
- be applied and RPM increased.
- The Underreamer can be opened and closed several times downhole if necessary.
- At the end of the job, stop circulation to close the arms; avoid moving up with arms open.
- Re-enter the casing slowly and watch for over pull, which could indicate partially open orjammed arms.
- Back on surface, rinse the tool with water.