Offshore Pipeline X Ray Crawler Image

  • Offshore Pipeline X Ray Crawler Image

    Posted by arsal on 27/11/2021 at 2:23 pm

    Hi,
    I am new to offshore and need some advice.
    While we are doing pipelaying offshore, normally there is 1/2″ buckle detector cable running through the pipeline. When we use the X-ray crawler to check for the weld quality, how can we ensure this 1/2″ cable will not interfere with the X-Ray image?

    lucas replied 5 months, 3 weeks ago 2 Members · 1 Reply
  • 1 Reply
  • Pipeline X-Ray Inspection

    lucas

    Member
    27/11/2021 at 10:38 pm
    2 Points
    Up
    0
    Down
    ::

    In truth the Level 3 or Engineer that established your exposure parameters (inspection procedure) should have accounted for this but if he didn’t and you are truly concerned you could try the following (but check with your lead or client before hand to ensure they are ok with it):

    For Double wall exposure set your source or camera up as you normally would but then offset your source or camera slightly (no more than 15 degrees) to the right leaving the film or detector plate in its normal position and take the exposure. Then move the source or camera to shoot the same exposure but offset it to the same number of degrees to the left and take a second exposure.

    If your 1/2″ cable is laid in the center, or fallen there due to gravity, then doing the offset exposures will allow you to shoot under the cable.

    If you have a perfectly perpendicular transverse crack which is tight you may not see it this doing this but you can improve even detecting this by paying very close attention to the grey scale density of your image Unless the transverse crack is exactly in the middle of the material under the cable you should see a density change though it may be slight.

    I am not a Level 3 nor do I profess to be an absolute authority or expert in Radiography but as a Level 2 with some experience that is something I might try. Others may have alternate ideas.

    Hope this helps. Cheers…