Road Bore Coating Post-Pull Analysis: DIRAX

DIRAX Post Pull Analysis

     We had a unique opportunity here recently.  On a large project utilizing some different two part liquid epoxies as their field joint coating, it was quickly determined that the epoxies were being damaged  beyond acceptable levels during the pull through.

     Now, I want to be clear - this was an extremely difficult pull.  There were large, razor sharp rocks sticking in the bore that were causing significant damage to anything that was being pulled through.  In my sixteen years of experience, I've never seen damage like this done on a lubricated directional drill pull through.  Never.  So I'm not saying there is or was a problem with the epoxies - I'm simply saying that they did not survive the incredibly challenging forces they were facing underground.

     The end user (after fully evaluating the system) decided that they would put a DIRAX shrink sleeve on the outside of the two part epoxy in order to add significant, added physical protection to that field joint coating.  Installations were done as normal when applying the two part epoxy - and then the DIRAX was installed directly on top of it (after the two part had cured).

     This introduced a 150+ mil layer of fiber reinforced polyolefin / polyamide material in the hopes that the DIRAX could act as a sacrificial coating preventing any damage from getting to the two part epoxy.  Fortunately, the DIRAX that was on the leading end of the pull through was pulled all the way through the bore so that it could be inspected.  The DIRAX was then cleaned off with a rag and a bottle of water.  Here was the result:

DIRAX after being pulled through a large directional drilling bore hole.

     Clearly there was a small amount of mud and dirt still left on the DIRAX sleeve, but all in all its performance was outstanding.  No tears in the sleeve; no holes in the sleeve, no wrinkles in the sleeve.  The DIRAX came through several hundred feet of being dragged through a hole and looks exactly as it looked just moments after installation.  DIRAX is an absolutely incredible product.