However, after the initial knowledge is attained, moving to the next level can be difficult without support from the manufacturers, dealers and service companies. Recognizing this need, schools and one-on-one training courses are available from an increasing number of sources. Utility construction, particularly in the gas and telecommunications industries, ensures a growing demand for the use of directional drilling techniques into the 21st century.
The potential for work spans the spectrum, from major river crossings to utility installation in congested urban areas, to various types of environmental remediation. Compact HDD systems can be used to install service lines to residences, without damaging private or public property, and other utility systems.
These usually smaller rigs are able to bore beneath driveways and sidewalks, existing utility lines, and underground sprinkler systems. Larger directional drilling equipment can be used to go under parking lots, highways, freeways, and even rivers and lakes. In addition, HDD offers unique solutions to environmental problems. For example, directional systems can install horizontal remediation wells to access contaminated soil and ground water in areas where other procedures are uneconomical.
Some in the industry predict the environmental market for HDD will eventually be larger that the utility market. Overall, HDD reduces restoration time and costs in both urban areas and residential neighborhoods.
The public appreciates the reduced inconvenience made possible by the use of directional drilling equipment. Companies usually consider the technical, contractual, and economic aspects of a project when determining whether to use HDD. In the case of a river crossing, the project is determined to be technically feasible if it can be installed using existing tools and techniques, regardless of uncertainties surrounding installation cost.
A crossing is contractually feasible if the installation cost can be accurately estimated in advance, allowing contractors to submit lump-sum bids. HDD is economically feasible if installation cost is less than the cost of competing construction methods. Mini-HDD is a subsurface-launched installation technique that typically uses either controlled-fluid cutting or fluid-assisted mechanical cutting.
However, this method can be use air for cooling or dry boring assistance, or can be a dry process where neither liquid e. Therefore, the choice of fluid-assisted or dry cutting depends on the nature of work normal utility application or environmental application , size of the utility line diameter and length , subsurface conditions, and impact on the environment.
Mini-HDD currently is not practical for installing pipe to the precise alignment and grade tolerances required for gravity sewer line.
However, mini-HDD is suited for installing new utility networks for water, gas, electric or telecommunication lines in developed areas. It can also be used to install pressure sewer line.
The diameter of the product pipe or utility line to be installed using this technique should be somewhere in the 2 to in. The depth should be less than 30 ft.
The dry system is suitable only for small-diameter pipelines typically less than 4 in. It is useful for drilling through soft soil or drilling under a sensitive, contaminated site where the probability of contamination movement to ground water or to the surface is high.
It may also be applicable where hazardous or toxic wastes have a high probability of contaminating drilling fluids, which would then require proper disposal. The main drawbacks of dry boring are the limitation of pipe size and overheating of the drill head as the bore diameter and the length of the bore increases. In the late 70s, Dick Melsheimer, working with Goldac Co. This locator served as a direct ancestor to modern-day walkover transmitter location systems, a core component of horizontal directional drilling equipment.
While this technology, as well as Cherrington's contributions, still wouldn't be commonplace for quite some time, they were key stepping stones toward a thriving HDD industry. The breakthroughs of the 70s led directly into the major technological developments of horizontal directional drilling equipment in the s — and that ball hasn't stopped rolling.
In , Dick Melsheimer started a new company called Borzall Equipment to focus on producing long-lasting reamers, bits and other HDD tools. Later in the decade, he would join back up with Melfred Welding to form Melfred Borzall. The late 80s saw significant leaps in magnetic steering technology, marking a turning point for the industry. In , Radiodetection, a UK utilities testing equipment company, produced the first radio transmitter also called a sonde.
The addition of sondes to directional drilling rigs would mean that drillers could know the orientation of the steer face on their bits, as well as the location and depth, allowing them to guide the bore fully.
And with that, HDD really started taking off. Also in the late s, a company called FlowMole produced the first true HDD rig of the modern era but did not make it commercially available. Instead, they sold their HDD services for installing utilities.
Around , Dick Melsheimer and the crew at Melfred Borzall began developing the first horizontal directional drilling rig that would be sold commercially: The Sure Shot Directional Drilling System.
It was available to contractors and drillers everywhere and introduced several revolutionary features, such as an electric strike alarm and electric over hydraulic control valves for improved control, visibility and safety. Melfred Borzall demoed the Sure Shot around the U. Horizontal directional drilling was now a global phenomenon in the construction industry. In , another major milestone happened in regards to walkover tracking systems.
Digital Control introduced the DigiTrak system, designed from the ground up to locate boring tools rather than cables as had been the standard. The DigiTrak quickly became a crucial piece of horizontal directional drilling equipment, giving drill rig operators roll, pitch and more accurate location and depth readings — and at deeper depths.
Mr Rankin recounts that the trip was right after hurricane Hugo had hit the Charlotte area and the storm had taken down several overhead powerlines at a nearby hospital. The directional drilling project involved moving powerlines underground to reduce any future loss of power to the facility.
Mr Rankin says he came back from that project not totally convinced of the technology, and wondering if he wanted to take the lead on a project to commercialize the technology.
He believed Vermeer was a company building trenchers nobody was going to shut down their trencher and follow. One is the early prediction of 10 units per year being quickly surpassed, resulting in an urgent need for more floor space to manufacture drills. Kind of hit that ball out of the ball park! I truly believe when I pull the boots on every day that there is a better way things can be done.
Vermeer is a company that keeps innovating, and one area that is becoming a focus for the drilling industry is environmentally conscious technology. The company has been making innovative developments with its fluid reclaimers, an area in which Mr Rankin has been heavily involved in recent years. While the trencher represented a major advancement for the installation of small pipe and cable in urban environments, it still faced one major jobsite challenge: like all open-cut excavations, the technology required major construction work to cross obstacles.
Case in point: prior to HDD technology, a simple road crossing often resulted in road closure, tearing up the concrete to excavate, and then fully rebuilding the road — taking several days to complete. Because of this inconvenience, the industry moved to innovate, with many working on different types of technologies to help solve the problem.
Early contractors — including Martin Cherrington and later Flow Mole, among others — created functional machines to combat these challenges; however, the machines generally lacked key elements of modern HDD rigs, which stunted their effectiveness.
Many at Ditch Witch were also conducting research to find effective trenchless solutions to HDD challenges. However, neither of these methods could point the direction of well drift. The urgency of finding better surveying methods and wellbore control techniques was sped up by the fact that this deviation of the wellbore was causing some parties to unknowingly trespass into oil fields of other parties by crossing lease lines.
The court ordered that leaseholders could only own deposits that were within their lease lines. Since the technology to control well drift was scarce and only possessed by a few, it was not uncommon for those with the technology to exploit the oil fields of their less fortunate neighbors. This dilemma led to the invention of survey instruments and deviation methods designed to control wellbore deviation to the required inclination.
In , H. John Eastman developed the magnetic single shot and multi-shot instruments that could measure both inclination and direction. This began the era of controlled directional drilling because it was accurate and could intentionally deviate wellbores to the desired bottom hole locations. It could also help restrict vertical holes from deviating beyond a few degrees of inclination, thus limiting wellbore drift.
Deviation was achieved by using hardwood wedges to push the bit to the desired side to produce deflection and direct the borehole to the desired direction.
From there, the oil industry has taken great strides in reaching multiple remote locations from a single entry point and also for harvesting oil from offshore rigs. This led him to design his own drill rig that was basic and lightweight. He performed road boring for the various utility companies in that area, and since electronic tracking had not developed yet, he used the technique of the handheld air drill he learned from the LA gas company.
That was the first milestone for HDD in construction, but there was more to come. It took him a month and several techniques including those used in the oil industry, but he made it. That was the beginning of using HDD for crossing environmentally sensitive areas with even bigger pipelines. About years later contractors started becoming comfortable with using HDD for installing utility lines, and today, it is a favored method for many construction projects especially for crossing environmentally sensitive areas such as estuaries and palustrine wetlands.
The evolution of HDD from the oil and gas industry to the construction industry has been noteworthy. While the concept was adopted and applied advantageously, the advancements in computer technology and surveying techniques, such as geotechnical investigation , has taken HDD to a far higher level than Cherrington could have imagined at the time.
This opened a wide avenue for the application of HDD from medium-sized to very large projects including crossings.
0コメント