In the past few years, there has been incredibly innovative technological advancements in the horizontal directional drilling industry. While the improvements of the drills themselves are the most noticeable-with automated rod loaders and stationary stake downs now the industry standards-it is safe to say that no other segment of the industry is more competitive or is pushed for more and faster technological advancements than the locating /tracking segment.
It wasn’t all that long ago that the electronics used to locate the drill head were nothing more than a couple iron ferrite coils that process the transmitted information through analog amplification and filtering. That information was then used to tell you the location of the tool and how deep it was. The user then had to decipher a series of tones, pulses or other types of audible sounds to determine the roll position. Everything else you had to figure out on your own.
Today’s locating equipment is as advanced as technology will allow. Some walkover locating systems now incorporate digital signal processing, compass steering indicators, transmitter temperature and multiple pitch compensating aerials. Recent advancements have also targeted the user friendliness of the locating equipment. All you need to know to locate the drill head is right from left and forward from backward. Once you get the indicators to light up, the location of the drill head and all pertinent information can be automatically displayed on the screen. This information includes depth, roll position and pitch inclination.
There are also locators that can distinguish the difference between the peak signal and the ghost signal, which are broadcast from the transmitter. This allows the user to accurately locate the drill head and prevents incorrect depth readings caused by inaccurate location of the drill head (caused by the ghost signal).
There have also been advancements in the area of interference. Until recently, when loss of signal due to harmonic interference occurred, there were few options. An option included getting a stronger transmitter. The lower the operating frequency that is used the less it will be affected by interference. Earlier this year, a dual frequency transmitter was introduced. This transmitter incorporates the lowest operating frequency in the industry (8kHz) and a high frequency (33 kHz). This enables the user the option of changing between frequencies at any time during the bore (without tripping out of the hole to change to a different transmitter). The transmitter can be changed from one frequency to another while down hole by using a simple coded rotation sequence. Thus far it has proven to be invaluable in interference situations.
What new locating technology might be in store for the future? A few things to look for in the near future would be enhanced automated nonwalkover steering systems and downhole avoidance electronics.
One of the most sought after new technology by the drillers is the automated nonwalkover steering system. Some of the more progressive companies in the industry are working to develop such enhanced systems that will provide the user with such things as nonwalkover location, nonwalkover depth and heading information. These enhanced systems may also incorporate such things as GPS coordinates.
Downhole avoidance electronics is truly new technology that is being driven by companies that are committed to protecting their underground pipes and cables. They are envisioning this major advancement in locating technology as being the best way to prevent damage to mislocated or unlocated underground utilities. Downhole avoidance means the transmitter not only would transmit a signal back to a receiver, but it would also receive signals from buried pipes and cables. The purpose would be to provide the operator with an early warning of a possible pipe or cable hit as you would be drilling. This concept would cover a variety of different frequencies and different utilities.
Needless to say, we are definitely headed for some very interesting times in the HDD industry.