Pipeline Industries Guild awards new beam drilling system technology

National Grid, GL Noble Denton & ALH Systems Ltd have, by working in partnership, won the coveted Utilities category of the 2012 Pipeline Industries Guild Awards. The award honours an innovative beam drilling system, which is used by UK gas network operators to secure drilling equipment onto gas pipelines more safely and more efficiently.

The beam drilling system was developed jointly with National Grid, one of GL Noble Denton’s largest clients, and gas network maintenance specialist ALH Systems Ltd under the UK Innovation Funding Incentive. It is based on a concept developed by National Grid and challenges traditional pipeline drilling practice. It saves considerable amounts of time and resource by removing the need to dig large holes in the ground to secure drilling equipment onto gas pipelines.

The system uses specially designed beams, which allow operatives to undertake a wide range of drilling tasks without having to enter the excavation they are working on. It also plays a significant role in improving the safety of working practices, reducing the environmental impact of pipeline drilling, delivering significant cost savings to operators and reducing road traffic disruption.

During development of the beam drilling technique, GL Noble Denton, the independent technical advisor to the oil and gas industry, undertook various calculations on the pressure, forces and stresses, to ensure the integrity of the system. The company also attended numerous field trials in order to perfect the equipment's development and its operating procedures, to ensure that it may be used safely and effectively. Written work procedures and training programmes were developed, and the company provided follow-up onsite support in use of the beam drilling equipment. This work has enabled National Grid to undertake operations more safely and with a reduced environmental impact, whilst achieving significant cost savings.

The beam drilling method is believed to the biggest change for thirty years in the procedure for attaching fittings to live metallic gas mains. The system enables gas free drilling and tapping into the crown of a main from ground level through a keyhole excavation or small slit trench. A new ‘top down working’ technique significantly reduces operative risks by enabling maintenance to be completed without the need to send any personnel into the excavation.

The system employs a weighted beam to provide controlled downward force, to create the gas-tight seal between the drilling base and the top of the main. This is combined with specially developed keyhole tooling for drilling, tapping, CCTV camera surveys and leakage repair treatments. Conventionally, the drilling base is attached using a chain around the main, which requires a large excavation to expose the complete pipe.

Developed with operator in mind

Jacking bars are reacted against beams along the road surface, which are held down by a series of weights at each end, providing a consistent mounting point and constant load. A two tonne weight load is needed to react against the bars, split into 50 kg weights to make it suitable for manual handling. A specially adapted ALH System 1 drilling system is used to drill holes up to 2.5 in. in dia. into the main under gas free conditions. Camera surveys, mainspray operations and service installations can then be performed from a single keyhole excavation.

Andy Sutherland, Best Practice Engineer, National Grid Operations West Midlands, explains, “The beam drilling system has been developed with the teams in mind, with operator and system safety being key factors within the design. The positioning of the beams and weights has been proven to reduce human fatigue and risk of injury compared to traditional trench support. Fundamental to the process is the removal of the operative from the excavation as specially designed long handled tooling is used to carry out the tasks to the gas mains.”

Reduced reinstatement and environmental impact

Dave Gregory, Senior Engineer at GL Noble Denton, highlights the advantages of the system: “Beam drilling offers three distinct benefits for utility companies - environmental, efficiency and safety. Combined with keyhole technology, the excavation to access a 48 in. main doesn’t need to be any larger than that needed for a 4 in. main.” Since its introduction in 2010, the system has helped reduce traffic congestion resulting from National Grid operations by more than 200 days.

The method has been used in a valve remediation programme in busy central London locations, and equipment is currently being used routinely for internal camera surveys, mainspray operations and for the installation of fittings. At a site in Canary Wharf, a fitting was successfully installed into the main, via a 0.6 m x 1.2 m excavation. The job was completed in one working day. Previously this would have required an excavation of approximately 2.5 m² x 2.5 m deep and taken around five days to complete. When used in The Mall, the small excavations facilitated by the beam system avoided damage being caused to the roots of mature trees; damage to these trees carries a significant financial liability.

Improved efficiency

Six beam drilling systems are currently being used to drive efficiency on each job. Training is delivered by GL Noble Denton over three days and includes workshops, practical and simulated exercises, followed by onsite experience. 

Contributed by Dave Gregory, GL Noble Denton

Read the article online at: https://www.worldpipelines.com/business-news/09052012/oil_and_gas_technical_service_provider_wins_award_for_new_drilling_system/