Case Study: MillRdillo (MLD) Switchable Deburring Tool in Vietnam

Published 26.04.2022

Integrity and efficiency combined


The client was looking for a solution to deburr the 9-5/8” perforated casing zone and recover debris from the wellbore. There was also a requirement to scrape a lower and upper completion packer setting depth inside the 9-5/8” casing utilising the same BHA.


Odfjell Technology offered the MillRdillo switchable deburring tool designed to safely mill and remove hard inclusions on the casing ID without causing damage and can be de-activated to disengage the Mill blades once the milling operation is complete.

To save a dedicated WBCU run and Rig time, the BHA was designed to incorporate all the WBCU tools required to recover and remove debris from the wellbore and scrape both the packer setting areas before running the completion.


RIH 923m of 2-7/8” drill pipe. Pick up and make up the deburr/WBCU BHA and continue to RIH on 5-1/2” Drill Pipe to 3367m. Work MLD/Scraper through packer setting depth from 3367 to 3802m. Circulate well to reduce gas level readings from 35% to 0.7%. Continue to work the MLD/Scraper from 3802m to 4185M. De-Burring operations completed, drop 1.875” MLD activation ball to disengage the MLD Mill elements.

Wash down to clean out debris from 4185m to 4201m (Top of Bridge Plug). Activate Circulation Sub and circulate well clean at 1000gpm with an Annular velocity of 161m/min, reducing the gas level to 0.5%. Close Circulation Tool and POOH.


We saved the client 47 hours of Rig Time with an approximate value of $391,000. All perforation zones and packer setting depths were deburred/scraped, with 6kg of metal debris recovered from the wellbore.

The completion was installed successfully with both production packers setting the first time.

Job Data
Onshore/OffshoreWell DepthOperations
Offshore4202 mDeburring & WBCU
Casing Specification
9-5/8” 47ppf
Milling Performance
MillSection Milled/CleanedParameters
9-5/8″ MillRdillo3367 m – 4185 m 6 kg
debris recovered
30 rpm,
350 gpm torque
6-9k ft/lbs

47 hours rig time saved
Mill elements can be deactivated
Reduces torque and casing wear
Extremely robust in challenging environments

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