Casing Collar Locator - long metal tube with black ends

Casing Collar Locator (CCL)

Making a depth correlation between the casing collars, and the open hole log of the well.

Product summary

Hunting’s Logging CCL can be used to make a depth correlation between the casing collars, and the open hole log of the well.

Logging CCL

Hunting’s Logging CCL, normally run with a gamma ray, CBL or other cased-hole logging tools, can be used to make a depth correlation between the casing collars, and the open hole log of the well.

Since open hole logs are used to select completion depths, the CCL log becomes a key depth control measurement for perforating, and for helping ensure the depth correlation of other wireline services performed in cased hole.

Hunting’s Logging CCL uses Samarium Cobalt (SmCo5) rare earth magnet material to produce one of the highest amplitude CCL measurement available, and maintains its strength, even at high temperatures. This is especially important in a flush joint casing and tubing environments, as well as logging with tools that must be run centralized in the wellbore.

Digital CCL

The Casing Collar Locator (CCL38 & CCL41) is used in cased hole for positioning measurement by responding to the changes in metal volume. The CCL detector consists of a coil and four magnets.

The four magnets are installed in pairs at the upper and lower ends respectively so that the coil is in a constant magnetic field. When the tool passes a collar, the magnetic flux is disturbed and an electric signal is generated.

The signal is then amplified and converted to frequency, which is then counted in MCU. When the telemetry cartridge polls, the count is sent to telemetry for encoding and then to the surface.

  • CCL38

    Digital - 43 mm (1.38”)

  • CCL41

    Digital - 35mm (1.38”)

  • Logging CCL

    Analog - 1.69" (42.9mm) - 4.50" (114.3mm)

    • Dependable, durable
    • More universal compatibliity with most bond tools


  • Collar location in cased hole for depth correction


  • Long life, high strength SmCo5 magnets

  • Alnico 5 magnet construction available for rugged environmental applications


  • Highly stable, sensitive and responsive CCL over a wide temperature range

  • Excellent performance in flush joint casing or tubing

  • Minimal CCL log desegregation at increased operating temperatures

  • Flexible with a wide range of cased-hole logging services

  • Suitable with all Hunting cased-hole logging tools

  • Wet wound pick-up coil helps increase durability and minimize failures