The Well Miller® RCB quickly identifies downhole obstruction

Downhole access
JCOL181092 Well Miller® Reverse Circulating Bit identifies downhole obstruction
  • Well type On-going drilling
  • Well fluid Drilling mud
  • Temperature 186°F at 4,010 ft
  • Pressure 1,920 psi at 4,010 ft
  • Inclination 69° @ 5,175 ft


In early 2018, a client in Colombia discovered a restriction at 4,570 ft while performing a free point log to release a 5” heavy-weight drill pipe.

The client needed to quickly identify the nature and cause of the obstruction material to continue the operation. The client called Welltec® for a ready-on-arrival (ROA) operation with the Well Miller 218 Reverse Circulating Bit (RCB) to clean-out and recover to surface the obstruction material.


After several approaches to the obstruction, the tool power flattened, indicating no more milling progress. The tool was pulled back, causing cable tension to jump 3,000 lbs indicating the tool string was stuck.

The client decided to pull out of hole to evaluate any recovered debris.
A thick, fiber-clay, mixed debris, was recovered - a consequence of products injected into the well to release the stuck pipe. The client then decided to clean all the way to TD using coiled tubing.


Welltec responded quickly in the face of a last-minute drilling need. The client was very pleased by the response and Welltec’s ability to adapt its tools and personnel in a ROA mode of operation.

This was the first time Well Miller RCB encountered this kind of debris, yet was able to retrieve it to surface in the bailers. The tool proved to be a slim, robust solution for quickly identifying the obstruction material, needed to decide on the next operation.