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Meeting cleaning and inspection challenges the green way

Hydrocarbon Engineering,

Much has been made in recent months about the rising cost base of undertaking activities in the North Sea as efforts are made to extract the remaining resources from the region. According to the Oil and Gas UK Activity Survey 2014, operating expenditure in 2013 rose by 15.5% to an all-time record of £8.9 billion, despite an 8% fall in production. A focus of today’s North Sea oil and gas industry, therefore, is to find new and improved means of working in order to reduce costs and improve efficiency. This mind set has encouraged challenge of best practices at almost every stage of the process. Yet, the smooth running and safeguard of assets is still as crucial as ever in the day-to-day running of operations.

Cleaning and inspection challenges

Complex pipe layouts and ageing infrastructure present a number of cleaning and inspection challenges. These can be compounded by access difficulties, which in turn can lead to the need for greater reliance on platform core resources such as the provision of scaffold for under deck access.

One of the companies rising to these challenges and leading the way in the provision of advanced and environmentally friendly water-based cleaning technologies to the North Sea oil and gas industries is Pipetech.

Established in Norway but now with a UK-based operation following its recent acquisition by Aberdeen-based Ramco Tubular Services, Pipetech has a suite of high-pressure water technologies to remove scale and debris from pipelines safely and without the need for environmentally harmful chemicals. The technologies, Aqua Sonic® and Aqua Milling® are operated remotely, enhancing the element of safety. This, coupled with the Aqua Milling capability to reach 500 m from a single entry point, hugely reduces setup requirements and down time.

Water-based, eliminating the need for harsh chemicals

Pipetech is licensed by Aqua Drill International to use the advanced and environmentally friendly water-based Aqua Milling system technology in Norway, Sweden, Denmark and the UK. Its mechanical method for removing scale and debris from pipes uses only high-pressure/high speed water (15 000 psi). The water is delivered through one of a range of specially developed nozzles deployed on the company’s flexible hose system, eliminating the need for harsh chemicals.

The Aqua Milling nozzles use the high flow rates of the water to clear returning scale from inside the pipework into a scale collector attached to the entry point. This system is fully enclosed with an inlet for the Aqua Milling hose and nozzle and an outlet for discharging waste, therefore ensuring that operating personnel are not exposed to any vapours, radiation or high-pressure water. The scale collector discharge outlet is connected with a hose that transfers the recovered scale to a holding skip/IBC to allow heavy waste to settle. Waste water is syphoned off to the operator’s preferred disposal route.

Protect assets and safeguarding the environment

This safe method enables an easy cleaning process for operators offshore to protect their assets and safeguard the environment. The use of water rather than chemicals reduces the amount of paperwork to be completed prior to mobilisation, and also removes the requirement to dispose of chemicals afterwards.

The system also has the ability to negotiate multiple bends from a single access point, fitting into pipe from 20 mm diameter up to large pressure vessels. The Aqua Milling system can manage up to 20 direction changes and can be used on a wide variety of piping materials including carbon steel, fibreglass, HDPE, PTFE lined, amongst others. Using specialised nozzles which are constantly moving over the surface and specifically selected for each work scope eliminates the potential for any damage.

The Pipetech system comprises of a zone II diesel driven high pressure/high volume pump, a twister along with a feeder to control the deployment of Aqua Milling rotating hose and over 200 nozzle configurations.

Scale removal

Aqua Sonic® is remote technology developed by Pipetech which has advantages over other scale removal techniques such as pigging, hand held lances and chemical flushing. Aqua Sonic® can be used in many different piping and process systems including heat exchangers. Hard scale can be removed from small bore pipeline systems with bends as little as 2 mm using a remotely computer-controlled cleaning process. This is based on "sonic resonance” which typically requires 75% less water than traditional cleaning. The computer-controlled software bespoke to Pipetech is tailored to optimise resonance, removing blockages without inflicting damage and implementing a safety factor based on pipework credentials.

This system comprises of a pump unit, laptop and control unit which together provides an effective pipe cleaning solution. This method is known as one of the safest, effective cleaning systems currently available within the industry.

Talisman Sinopec North Sea case study

Pipetech recently completed the Aqua Milling of a 6 in. gas import riser for North Sea operator Talisman Sinopec. The team mobilised to the Claymore platform to clean the riser for inspection, which could not be cleaned by conventional methods due to the tight bend configuration near the access point.

Pipetech initially demonstrated its ability to the client by negotiating the bend layout on an onshore piping mock-up which replicated the most challenging bend configurations. Following the successful demonstration, the Pipetech team were contracted to complete the job.

Successful Pipetech demonstration in Bergen prior to mobilisation offshore.

Mobilising offshore within a controlled worksite, Pipetech used the fully contained, remotely operated jetting system at 140 m depths and at a 950 barg working pressure. The system negotiated six bends - two at 45° angles - using the specialist nozzle deployed on the company’s flexible hose system. Accessing the riser through only one access point, the company completed the job within a 16 hr cleaning timeframe.

The Aqua Milling system was managed remotely, providing an additional level of security. All scale was removed, collected and disposed of in a safe, clean and dry operation. The work was performed without incident, maintaining Pipetech’s zero LTI record.


There is no doubt that the industry in the North Sea is changing in response to the demand for efficient operations, as well as the stringent health and safety requirements. Cost pressures across the board are encouraging operators to work in a more smarter and competent manner.

Pipetech has recognised the need for more efficient processes offshore and has provided the North Sea industry with a service fit to meet these requirements. Cleaning pipework without causing damage eliminates the need to replace impaired pipes, saving the operator money.

The increasing scrutiny of the environmental impact has an effect on the day-to-day processes of activity in the North Sea. Therefore by eliminating the need for harsh chemicals, operators are able to reduce both risk and time when mobilising technology offshore. 

Pipetech’s ability to manage its systems remotely using computer technology also provides an additional level of security, surpassing similar cleaning systems in the marketplace.

Written by Leonard Hamill, Operations Manager, Pipetech. Edited for web by Cecilia Rehn.

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