“Bird-Friendly” Tornado Tool Process™ Implementation in The Netherlands

The Ameland Island: Overcoming the environmental challenges.

Ameland is a municipality and one of the West Frisian Islands off the north coast of the Netherlands. It consists mostly of sand dunes. It is the third major island of the West Frisians.

The AME well site is located on the east side of Ameland Island. Well services operations are often subjected to local environmental regulations, dictated by bird migration, weather conditions and tourist seasons from spring to autumn each year.

Ferries sail from Holwerd in the province of Friesland to the small town of Nes in Ameland. Hundreds of commuters and tourists travel back and forth to the Island, along with supply trucks, mail and cargo, etc.

Most of the year, especially on spring and summer, the Island is quite busy with active tourist activity and night life. Dutch citizens like the island to spend Summer time on the beach, as they call it “The Frisian Antilles” (from the Dutch – “de Friese Antillen”). Lots of hotels, hostels and cabins get packed with tourists and visitors at that time of the year.

That entire busy vacation schedule leaves just a little room for well operations to come through, as part of the local regulations contemplate prohibiting trucks and heavy load trailers transit across the beach. Eco-tourism is also very intense, as a diverse bird fauna is object of research throughout the year.

Fig.1 Ameland Island located on the Dutch North Sea (Courtesy Google Earth)

The Nederlandse Aardolie Maatschappij b.v. (NAM*), oil and gas operator based in the Netherlands, has researched bird species in the area since 1992 and introduced measures such as dimmed lighting and reduced flaring to protect the birds’ natural environment.

North Sea is an important migration route for more than 60 million birds twice a year. Many birds undertake ten-hour flights across the ocean and have only twelve-hour fat reserves to keep them going. So any delay to their flight time (such as resting on platforms or circling around them) could be dangerous.

Research conducted on the behaviour patterns of seabirds showed that, while the noise from offshore oil and gas operations does not disturb them, the light from platforms does. The

Manuel S. Navarro – BJ Emmen - The Netherlands.

solution was to turn out the lights (without impacting safety) and change to different colour lights, since it is the red part of the light’s spectrum that upsets the birds’ compass.

In response, NAM enforced an effective new type of lighting. They had to take into account the birds’ sensitivity to the red part of the light spectrum, but also the human safety conditions on the platform. It took some time to determine the most adequate light colour spectrum for offshore applications.

Blue lighting would however mean less safe conditions for the people working on the platforms, partly because that kind of light impairs the sharpness of one’s sight. Fire extinguishers are also less clearly visible in lighting without the red part of the spectrum. NAM and Philips got round the table with this information and jointly set about developing a new type of light that would not distract birds whilst at the same time and will at the same time not impair safe working conditions. In 2007, lights were installed on the offshore production platform L15. The experiment proved a great success as the number of birds circling the platform declined by over 50%. NAM also participated in a land-based project on the island of Ameland where the ferry land dock part of the public road system was equipped with bird-friendly lighting, so called “green lights”.

Fig.2 Ameland “bird-friendly” green-coloured lighting (Courtesy of Shell and Phillips NL)

Getting the equipment on site is a complex logistic operation because everything needs to be transported via the beach. The access to the location is only possible through the environmentally protected area of the north shore. Special transport trucks are necessary to manage heavy loads over the beach and sand dunes all the way from the ferry dock to location. Crews and personnel also need 4x4 vehicles to get there.

Well Ame-106 was spud in November 1989 and completed with 5” Cr-13 tubing. It is producing from the main Ameland East block. Units 3 and 4 are the most prolific layers contribution to 75% of the total gas flow.

Manuel S. Navarro – BJ Emmen - The Netherlands.

Fig.3 Special transportation trucks carrying BJ equipment on its way to location AME(Courtesy of NAM-Shell)

Tornado Tool Process™: First-time implementation for Shell in Holland.

Beginning of 2008 the well was flowing 0.5 Mm3/d at 20 bar (290 Psi) FTHP. After a short shut-down, the well suddenly produced only half of its normal capacity. A HUD run showed an increase of sanded-up by some 50 m. Consequently, the well died due to liquid loading. After a month the well started to produce at its current rate of 0.2 – 0.25 Mm3/d at 20 bar (290 Psi) FTHP. 3 m (9.8 ft) of sand has been cleaned out. During a SPG/HUD run performed at the end of October 2008 the HUD raised another 10 m (32..8 ft). Some dry fine sand was bailed out.

The sand fill in the 4 ½” liner covering > 70% (compared to the HUD in 2004) of the perforations, caused the flow rate to become critically low. The well started to liquid load and had to be shut-in occasionally. The SPG survey in October 2008 showed 39.5 bar (573 Psi) BHP. A coiled tubing clean-out operation using the Tornado Tool Process™ was proposed by BJ Services NL on AME-106 in January 2009, to restore the well's performance.

After accomplishing the equipment mobilisation from Emmen base to Ameland location, rig-up process was followed as planned, using special transports in order to deliver all coiled tubing components to the actual job site. After rig-up, required safety meetings and tool box talks were held on location, in order to assess and verify all details and contingencies as applicable.

After reaching theoretical sand-fill top, energized fluid was pumped through the CT in order to fluidise the sand and circulate it out of the well. The Tornado Tool™ (forward jetting RIH mode) was able to break two sand bridges along its way to target depth, as evidenced on actual job data.

After reaching target depth, Tornado Tool™ rearward jetting was activated by increasing the pumping pressure. Boosting the nitrogen share on the nitrified fluid increased the pressure differential achieved on the tool string; hence the wiper trip was performed as per plan.

Manuel S. Navarro – BJ Emmen - The Netherlands.

Fig.4 Overnight Coiled Tubing operations on AME-106 well using “Bird-Friendly” lighting - Ameland

(Courtesy of NAM)

Taking advantage of the rearward jetting feature of Tornado Tool™, a single-wiper-trip was sufficient to circulate the sand out of the well. Accurate data provided by the customer, largely contributed to the success of this job, as computer simulations dictated the optimal wiper trip speeds and pump rates required to clean the well bore completely.

The cleaning of the well was executed satisfactorily, and in accordance with the software simulations. However, the recovered sand could not be quantified due to the small size of the sand grains. Additionally no solids separation system was in place to collect the solids flowing along with the fluid returns towards the brine pit on location.

After the wiper trip, well production assisted cleaning the perforated zone, helped and maintained the circulation of the well in steady growth, and still flowing back fluids with its own energy after rig-down…

Initial production flow = 220,000 m³/day Final production flow = 550,000 m³/day The implementation of the Tornado Tool Process™ for deep-low-pressure wells in Holland is for NAM a new, practical and reliable option to successfully clean and maintain gas producing wells for maximum reserves recovery.

Used totals:Total running meters for 1-3/4” string 3,673 m (12050 ft)Nitrogen volume used (in gas) 18,700 nm³ (660,000 scf)Fluid volume used (1.02 sg KCl brine) 62 m³ (390 bbls)

* NAM (50% Shell / 50% ExxonMobil)

References:- www.shell.com - www.nam.nl - www.phillips.com

Special thanks to:- Rob van der Klooster (NAM – Assen, NL) - Alan Pillar (BJ Services, NL)- Peter de Boer (NAM – Assen, NL) - Henk Stork (NAM – Assen, NL)

Manuel S. Navarro – BJ Emmen - The Netherlands.