Underground Construction - December 2021 - 35

Directional Drilling
Making Difficult HDD Intersect
Bores Practical
Jeff Griffin | Senior Editor
Picture two large directional drilling rigs several thousand feet
apart - usually on opposite sides of a body of water.
Each rig drills from its location, and the two pilot bores meet
at a precisely-planned point in between. Successful horizontal
directional drilling " intersects " always attract attention in the
industry. Today they are not uncommon, but certainly can't be
called routine, and there aren't many drilling contractors with the
equipment, know-how and experience to undertake an intersect.
Several years ago, a driller discovered that a simple locking
swivel could simplify intersects.
The story begins at North Houston Machine Inc., a company
offering downhole products for multiple types of drilling
operations, including horizontal directional drilling (HDD). In its
product line is an HDD locking swivel.
" We designed the swivel to rotate freely to allow fluid to pass
through, or to lock, stopping rotation, " said North Houston
Machine (NHN) owner Mike Mannen. " With two rigs placed at
each side of the bore, the swivel is used on the pull side or exit
side to allow fluid to pass through and rotate freely. When it
comes time to breakout the pipe, the swivel can be switched to
the lock position.
" The benefit of being able to lock the swivel creates a safer
and more efficient way to begin removing the pipe. And 'free
spooling' helps eliminate unnecessary stress on the equipment
which allows machinery and tools to last longer. "
Mannen said changing the swivel from " free spool " to " locked "
is simple. There are four socket head cap screws to loosen, slide
the locking ring over the mating hex, tighten the bolts, and the
swivel will be in the " locked position " .
History
It's not clear how long free spooling has been employed
with intersects.
" We have been making locking pull swivels for over 15 years, "
Mannen said. " A superintendent at Direct Horizontal Drilling
told me they have been using them in " intersecting " applications
for at least five years. Word has spread through the industry
about the benefits of free spooling for intersects. Pull swivels are
in our catalog, and we have featured it at trade shows. We have
seen an increase in sales. "
Mannen said other companies also have locking swivels, but
the locking/unlocking process in not as simple. NHM has two
patents on its locking swivel design.
Established in 1979, North Houston Machine, Tomball, Texas,
has a fully-equipped machine shop with precision weld and
fabrication facilities and specializes in custom-design products
such as rotary heads, swivels, side feed and conventional swivels
for air, water or mud drilling, and designs and manufactures
drill pipe and tool joints for water and seismic drilling. NHM's
patented breakout system requires no tongs or wrenches. *
FOR MORE INFORMATION:
North Houston Machine, (281) 351-8108, northhoustonmachine.com
Drawing of free spool and locked swivel.
UCONonline.com | DECEMBER 2021
35
http://www.northhoustonmachine.com http://www.triflo.com http://www.UCONonline.com
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