What Are COLT and POLARIS Bottom Hole Assemblies in AnTech's CTD Service?

Updated

COLT and POLARIS are the two proprietary bottom hole assemblies (BHAs) that AnTech uses to deliver directional coiled tubing drilling (DCTD). COLT is the directional drilling BHA, and POLARIS is the casing exit system used to start a new directional wellbore from an existing well. Together they are the technical core of AnTech's coiled tubing drilling service: COLT does the steering and drilling, POLARIS creates the window that lets the assembly leave the original wellbore.

What each tool does

Tool Role in the CTD service Where it fits in the operation
COLT Directional coiled tubing drilling BHA Steers and drills the new directional or horizontal section
POLARIS Casing exit solution Mills a window in existing casing so drilling can begin from the parent well

The distinction matters when you are planning a job. A casing exit is a prerequisite for most re-entry directional drilling, so POLARIS is typically the first tool downhole. COLT then takes over for the drilling phase, where the BHA has to deliver directional control while the coiled tubing provides the conveyance.

Why AnTech pairs them with underbalanced drilling

AnTech's service description states that it provides directional and horizontal wells "whilst drilling underbalanced." Underbalanced operation is a deliberate choice, not a default: it is used to reduce formation damage and improve productivity in reservoirs that would be harmed by overbalanced drilling. Both BHAs are designed to work within that operating mode, which is why they are presented as a matched system rather than standalone tools.

What the service around the tools includes

The BHAs are not sold as isolated hardware. AnTech describes a complete DCTD service that covers:

  • Project planning before the job
  • Liaison with rig and fluid handling providers
  • Supplying the tools and the crew to complete the job

So if you are evaluating COLT and POLARIS, you are really evaluating a service package. The tools determine what is technically possible; the planning, fluid handling coordination, and crew determine whether the job executes as designed.

Where the technology is being applied

AnTech positions CTD as suited to both conventional production work and energy transition applications. The site lists:

  • Geothermal
  • Mining for critical minerals
  • Drilling for hydrogen
  • Carbon capture and storage

It also notes that with production increasingly coming from mature fields, operators are looking at CTD as a way to reach untapped reserves and extend well life. That is the commercial case for a casing exit plus directional drilling system: you add drainage points to a well you already own instead of drilling a new one from surface.

How to decide whether this fits your well

COLT and POLARIS are relevant if you have an existing well with casing you can exit, a target that requires directional or horizontal reach, and a reservoir where underbalanced drilling is acceptable or preferred. They are less relevant if your objective can be met with a straight re-entry or a conventional rotary drilling program.

To move from general interest to a specific answer, the practical next step is to bring your well data — casing details, target location, reservoir pressure — to AnTech and ask them to confirm whether a COLT/POLARIS program is feasible. The site routes this through its enquiry and "Information for Operators" sections rather than publishing selection criteria or pricing.