Horizontal Directional Drilling (HDD) is a trenchless technology process that allows the installation of new piping (or the repair / replacement of old piping) underground without opening a trench for the full length of pipe. The development of this technology has saved time, expense and environmental disturbance for construction and maintenance companies in many industries including Oil and Gas.

Oil and Gas Pipeline Construction and Repair

It is estimated that there are approximately 2.5 million miles of pipelines to transport fuel products from source to market in the USA. Most of these pipelines are installed underground. Steel piping is subject to corrosion, and as such, is regularly monitored and repaired or replaced before its integrity is threatened. In addition, new shale gas exploration sources require the laying of new pipes in order to get the gas from the source to the processing plants for distribution.

The oil and gas industry is, therefore, a significant customer of piping construction and repair contractors, and the availability of HDD trenchless technology is creating opportunities for improved efficiency and costs. Trenchless rehabilitation is a smart move for them. The following factors are contributing towards the shift to HDD by oil and gas companies. (Learn more in "7 Types of Trenchless Rehabilitation Methods and How They Are Used.")

1. Environmental Factors Supporting HDD

Digging continuous trenches has a far greater impact on the environment than using HDD technology. This is particularly important in areas where there is a sensitive ecology like wetlands. Geo surveys can be conducted throughout the area in order to determine the best route for the pipeline taking environmental considerations into account. Environmental groups monitor the loss of natural vegetation and reduction in forestation as a result of construction activities, and as such, increasing pressure is placed on companies to minimize this impact when commencing new construction projects.

The shorter the pipeline, the less potential for adverse environmental impacts. The oil and gas industry has moved towards HDD technology because it enables the most direct route from source to destination, thus minimizing the distance of underground piping and associated risk.

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Erosion and sedimentation are also factors which favor HDD techniques over the conventional digging of trenches. Disruption to soil layers through trenching increases the risk of erosion, especially during heavy rainfall, which can expose underground pipes causing damage and creating an opportunity for human interference. The resulting loss of soil also causes damage to surrounding vegetation and loss of valuable ecosystems for living organisms.

2. Technological Improvements of HDD Equipment and Methods

As technology has improved in HDD systems, they have become more attractive to the oil and gas sector. These improvements include the following:

Improved Steering Capabilities of HDD Rigs

There has been an improvement in the measurement and steering capabilities of HDD rigs in order to accurately install the piping in the optimum route. Due to the improved accuracy in steering, smaller bore casings can be used, which saves cost, while obstacles can be avoided more easily.

New Chain Drives

Rack and pinion technology has generally replaced the chain drives to move the carriage forward. The newer drives are more durable and reliable, which makes the operation more efficient and means that projects run more smoothly and to schedule.

Mud System Improvements

Improvements in mud systems have also yielded positive returns in terms of HDD installation projects. The constituents of mud, pumping and filtration systems all influence the effectiveness of the drilling operation.

Grouting and Lining Materials Advancements

Lining materials and chemical grouts have advanced due to the applications of trenchless technology. As rehabilitation companies have gained access to increased lengths of piping and been able to more accurately determine rehabilitation needs, the companies providing solutions have developed their products in accordance with these advances.

3. Regulatory Pressure

The United States Department of Transportation has a regulatory board for pipelines called the Pipeline and Hazardous Materials Safety Administration (PHMSA). Requirements for the integrity management of pipeline networks are specified and monitored. Over time, the increasing demands of integrity testing and inspection of older pipelines have raised concerns with piping that may have been laid many years ago in rural and undeveloped land, but now lie underneath housing, roads and commercial activities. HDD technology is ideally suited to respond to this increase in regulatory demand, as piping can be repaired or replaced with minimum surface disruption; this includes the use of robotic pipe repair. (Read on in "An Overview of Robotic Pipe Repair.")

Regulatory pressure is also driving some improvements in HDD technology itself through the development of standards for the treatment and disposal of drill mud and cuttings.

Regulators world wide continue to amend their standards in line with best practices and international norms. Fines for failure to comply are rising significantly and companies are turning to trenchless technologies to manage their pipeline integrity and maintenance.

The oil and gas industry, with its vast network of interconnecting pipeline systems, is taking advantage of the benefits of trenchless technologies like HDD. The sheer length of piping alone makes the task of integrity management a major undertaking, which requires efficient and cost effective methods of construction and repair.

Environmental factors, technological improvements and regulatory pressure have all played a role in the shift towards HDD and this trend seems likely to continue and grow for the foreseeable future.