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April 2020 – Horizontal Well Surface Completions

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Horizontal Well Surface

One of the common questions we get when
working with consultants and owners is “what does a
horizontal well completion look like?” When pressed, most
of the time our answer is “it depends”. We’re not trying
to be flippant; it really does depend on many different
factors including:

  • Above or below ground
  • Well use
  • Physical location of
    the well head
  • Will well
    rehabilitation be required
  • How many wells will
    be terminated at the completion


Before we get into types of
completions, let’s remember two things; 1) horizontal wells
have relatively shallow entry angles (usually from 0° to
about 25° above horizontal). 2) most, if not all wells will
need some sort of rehabilitation during their useful life.
Why are these two points important? At some time in the
future you may need to access the well to pull a pump or
injection tubing, perform a video survey and/or jet the well
screen. Because the well exits the ground at a shallow angle,
the surface completion should be designed with future access
in mind. In other words, long, skinny vaults may be a better
choice than a traditional, small, round completion.


To the right is an example of a horizontal
sparge well with a flush mount completion.  Note
that the box is longer then it is wide.  Also notice
that the 4” HDPE casing terminates in the vault with a
“Y”.  One end dips into the ground and connects to
the sparge blower.  The upper side of the “Y” is
capped and set up as a clean out port.  The cap can
be removed, and a rig or jetting truck can easily access
the well for video or rehab activities.


Horizontal wells with above ground completions are
a small percentage of our total installations. Many of these
completions are for wells where submersible pumps are
installed, or the well is utilized for industrial or municipal
water supply. Complex instrumentation and controls, power
drops, flowmeters and even sample taps are difficult to place
below ground and access. That makes above-ground surface
completions the go-to standard for pumping wells. Well access
is certainly easier; the above ground piping can be easily
accessed, and a rig can be placed directly behind the well for
rehabilitation activities.



Some of our environmental remediation horizontal
wells are placed in complicated areas requiring innovative
surface completions. For example, in 2018 Ellingson-DTD crews
completed two wells in a downtown area of a large West Coast
city. The wells are being utilized for both dual phase
extraction and injection for a UST leak clean up. The rig up
area was extremely tight on a narrow sidewalk, squeezed between
a multi-story building and the street. This required the crew
to drill both wells, blind (single-ended) completions with a
total length of roughly 140’, from the same small entry pit in
the sidewalk. The final surface completion had to include both
wells, be flush to the sidewalk, securable and stable for foot



Finally, sometimes things really get weird…This is
a particularly complicated surface completion. The long, blind
single entry well is used for groundwater containment at an
industrial site. The wellhead surfaced in a high-traffic area
and the groundwater level was nearly at the ground surface.
This is sort of a combination completion, both above and below
ground, protected from traffic by very stout bollards. The
field crew called this one the “Bomb Shelter”.



Many times, we recommend that the consultant
contact a local contractor to complete the well head. It is
most efficient for the surface completion to be constructed
when the well is connected to the treatment system, and those
connections typically get installed long after the well has
been drilled. Especially for flush-mount style completions, it
is easier to make the subsurface connections before or during
the vault construction, rather than dealing with going under
the vault’s concrete apron. So, it’s just easier for whatever
contractor is making those connections to also build the vaults
after they’re done.

There you have it, a short synopsis of the different options
you can choose from to complete wellheads for horizontal wells.
We can complete the installations as flush mounts, above grade
or combinations of both. We can be as creative as you need for
the specific site conditions, but please remember, bigger and
complicated means expensive and time consuming. It really all
depends on what connections you plan to make, and that probably
means we won’t even be involved.

If interested in a brown bag to learn more about
this technology please contact David Bardsley 713.545.1859 or