Page 20 - AL811 2022 issue 4

Horizontal
Directional
Drilling
Lessons Learned
By Roger Cox ACTS Now, Inc.
The history of HDD
Martin Cherrington conceived the idea of
horizontal directional drilling in the 1960s. He first realized the value of underground drilling when he and another contractor were given the same job: lay down telephone lines in Los Angeles. The only difference was that Cherrington was using an open trench method while the other contractor was using drilling to lay down cables. That contractor arrived two weeks after Cherrington
yet managed to finish two weeks before him. This led Cherrington to believe there was merit in looking at underground drilling methods.
In 1964 Cherrington founded Titan Contractors, which specialized in utility road boring. It was an opportune time for the company’s formation because of a building boom in Sacramento and a recent “beautification” decree from the First Lady, Lady Bird Johnson. The decree was instated to clean up America by getting rid of utility lines which were an eyesore and hazardous during seismic and extreme weather events. As a solution, Sacramento proposed placing all utilities underground. Despite a favorable environment and HDD’s merits, however, other, more familiar tunneling technologies like jack and bore and auger boring were usually preferred.
One of the main problems was the lack of control when drilling. It was often very difficult to make a straight bore, and the drill bit would resurface in unexpected places (like the middle of the road). Cherrington realized a solution when an engineer from PG&E invited him to consider
a project for placing a gas line underneath the Pajaro River. The project would require drilling underneath the river, and the variability of the drill bit’s direction would make it challenging. To find a solution, Cherrington experimented with angled bores on a similar river, trying several different angles. He observed that the steeper the angle of the bore, the greater the achieved distance. This relationship between angle and distance helped prove that with “optimum entry angle, proper drilling techniques
and the right downhole tool assembly” (Cherrington)
HDD could be used to cross a river. Since then, familiarity with HDD has increased, and it has become a much more routine method for projects requiring a non-evasive boring solution.
Lessons learned
Ok, admittedly I’m an old guy and somewhat of a
history buff. However, over the past 25 years I’ve had the opportunity to visit a number of HDD companies, most
of which were not really HDD companies at all. Just contractors trying to make a living and to do a good job. While hanging around these great folks, I learned a little... all while making great friends in the industry.
Some of the things I learned from these pioneers was
the industry was developed out of a need, a need to limit the social and environmental impact of open trench construction while installing critical utility lines. There had to be a better way than tearing up flower beds, blocking traffic for months on end or creating mud slides for folks to trek through during the rainy seasons.
Back in the earliest days, backhoes or track hoes were pushing pipe under city streets with their buckets. As
18 • Alabama 811
2022, Issue 4