Every now and then it’s fun to kick back and think about past horizontal well projects. Ellingson-DTD started as Directed Technologies Drilling (DTD) way back in 1996. In those days horizontal environmental well projects tended to be few and far between.
Fast forward to the current Ellingson-DTD; horizontal wells are mainstream when it comes to remediation projects. Pretty much all subsurface remediation technologies can and have been implemented using horizontal directional drilling technology. In fact, we’ve even completed a couple of thermal projects over the last several years
The typical site has also changed. Early on in the development of the industry, the locations were mostly large industrial facilities, sites such as rail yards, chemical plants and Department of Defense (DOD) facilities. Currently we are working on a much wider variety of sites, both large and small. Now-a-days completing very short, shallow horizontal sub slab vapor mitigation wells is all the rage.
But let’s go back to the whole DOD thing again.
Environmental remediation activities at DOD sites benefit greatly when implemented with horizontal wells. Many of these facilities date back to pre-WWII and contain miles of fuel piping and acres of land underlain with areas where solvents, firefighting chemicals or other toxic chemicals were used and spilled.
Keep in mind most of these facilities are very large, incredibly active and have lots of places non-military folks aren’t welcome. Think about active runways/taxiways, munitions storage areas, petroleum oil and lubricant (POL) storage locations, research buildings, aircraft hangers/repair shopw, vehicle maintenance warehouses; the list is almost endless.
Designs utilizing horizontal wells give consultants and facilities managers the ability to remediate sites with minimal impact to ongoing base operations without massive encroachment into secure areas.
A Trip Down Military Lane
We did a quick review of projects completed by our field teams at DOD facilities since the company’s founding and the data is quite interesting. We have worked on one hundred, fifty-seven (157) horizontal wells at DOD sites. This breadth of work encompasses thirty-two (32) individual locations across sixteen (16) states and Puerto Rico (see map above).
Three of the project locations, Alaska, Hawaii, and Puerto Rico had us mobilizing equipment in containers and on seagoing barges.
So what type of horizontal well work have we done at defense sites you ask?
It’s been an interesting history review. Horizontal wells completed by Ellingson-DTD have been used for the following remediation activities:
ground water extraction
soil vapor extraction
in-situ thermal remediation
sub slab vapor mitigation
and finally Ellingson-DTD has completed two Horizontal Reactive Media Treatment Wells (HRX Well®)
We have also performed multiple horizontal well rehabilitation projects requiring video inspection, jetting and pumping activities. We have even rescued a couple of projects where other directional contractors could not complete the work!
Additionally, our teams have abandoned several existing horizontal wells and even did a horizontal soil sampling project at a former DOD site.
Several of these projects stand out as “really cool”, although we can’t go into too many specific site details.
Very, very, looooooooong sparge wells
Ellingson-DTD installed two biosparge wells at on an air force base underneath the flight operations area. One of the wells was 2,069’ in length with over 1,100’ of screen. The second well was 1,920’ in length. Both wells consisted of 3” diameter HDPE screen and casing and required highly specialized installation techniques to ensure the well materials wouldn’t break during the installation.
Our crews were tasked with the abandonment of two stainless steel horizontal extraction wells ahead of a new thermal trea
tment installation. Each well first required a video log to verify the material condition. We then mechanically perforated the stainless steel riser pipes and screens. Finally, high temperature grout with silica sand was emplaced via the tremie method to seal the perforated wells.
DTD crews obtained soil samples under occupied residences to test for contamination. Subsurface conditions at the former DOD site consisted of fill and dredge spoils. Most of the samples were obtai
ned about 10’ from the building edge at a depth below ground surface of 3’ – 4’.
DTD completed the first of its kind horizontal passive treatment well at the site. The crew completed the well in a continuous (entry/exit) borehole at an active DOD facility. Well materials consisted of shielded, stainless steel wire-wrap screen in a proprietary, patented configuration. The well is about 567’ in total length, installed through the long axis of the plume. Read more about the HRX Well® technology here.