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Tue 20 Apr 2010 04:00 AM

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Downhole demands

Choosing the right drill pipe coating for tough drilling environments can save operators millions of dollars over the course of a field development plan.

Downhole demands
Jack Dyer, NOV Tuboscope.
Downhole demands
The interior of pipes can suffer from the harsh conditions in which they work.
Downhole demands
Coating of pipes is crucial.
Downhole demands
The coating of a pipe can negate the need for expensive high grade steel.

Choosing the right drill pipe coating for tough drilling environments can save operators millions of dollars over the course of a field development plan.

When a drill pipe is rotating, pushing and even steering thousands of feet below the surface through difficult carbonates and geological formations, it is, somewhat surprisingly, the pipes interior that is really taking a battering.

All the mud, rock and injected fluids under pressure have a corrosive effect on the pipe core which can cause failures within the drill-string well ahead of the external abrasion.

To hold at bay the erosion within the pipe, operators can select high-grade, stainless steel or exotic high grade alloys to prolong the pipes safe and effective lifespan. This is expensive. High grade alloys can run to thousands of dollars per foot of drill pipe - an eye watering cost to an operator planning an 18,000 foot long well.

However, standard, API approved carbon steel, which comes in at a fraction of the cost can be used - if is protected from the elements.

"NOV Tuboscope has tailored an impressive array of around 40 internal plastic coatings to protect drill and line pipes specifically for use in oilfield applications. The technology uses phenolics, epoxies, urethanes, novolacs and new thermoplastics that are designed to address the unique operating needs of specific oilfield environments," says Jack Dyer regional sales manager, NOV Tuboscope.

Depending on the downhole environment, fluid chemistry, or temperature and pressure ranges different thermoset and thermoplastic polymers can be selected for their specific chemical and mechanical properties and ability to perform in tough corrosive environments.

"In the Middle East, because of fairly commonly occurring geologic conditions and regular recovery techniques, there are perhaps six or seven coatings which dominate our sales for the region - including one of the only coatings which is approved by Saudi Aramco for use on its Khuff formation gas fields, which is highly H2S rich gas," explains Dyer.

The company has experience with some of the most sour production environments anywhere, thanks to its 149 country footprint. "There are examples, globally and regionally, where pipe failure has been attributed to H2S content and we have managed to solve that with the right chemical coating for protection," says Dyer.

Because of the high cost of exotic alloy or stainless steel pipes, and a proven pedigree with many of the industry majors, Tuboscope has found its coatings in ever-greater demand in the Middle East.

"In terms of the total economic package, an operator can maintain a lower grade of steel and deliver the same performance at around a third of the cost," reveals Dyer.

However, despite an obvious commercial benefit, selling on economics alone is not enough to penetrate the Middle East market. "The business case may be outstanding, but it's a tough and lengthy process to get specifications changed with National Oil Companies in the region. Whilst a lot of local wells may not necessarily be classed as difficult, the downhole environment can be quite challenging, and with extremely sour oil there is a tendency to over-engineer and over-design in order to ensure a broad safety margin," he says.
Local Motion

Until recently 100% of API accredited drill pipe was imported to the region from steel mills abroad. However, seamless drill pipe manufacturers are flocking to the region, initially in Saudi Arabia, but also in the UAE. Dyer says that local market dynamics is changing the dynamics of drill pipe procurement.

"Now that pipe manufacturers are coming up in the region I am sure there will be string support from operators or even National Oil Companies to see these businesses flourish. Building up local capabilities has long been an ambition in the Middle East, and this is an opportunity I can see being seized."

In order to ensure a smooth and efficient supply chain, from the operator order through to pipe delivery, NOV Tuboscope has 16 pipe coating plants dotted around the globe, in close proximity to major manufacturing partners. "In order to maintain that speed and flexibility, now that local mills will be making a larger portion of the pipe used in the Middle East, we are building our own state of the art coating facility in Abu Dhabi's Industrial City (ICAD)."

The new facility will be operational this year, and tours of the coating plant and its technology will be arranged at this year's ADIPEC event.

"These local mills will want to compete on a global scale. In order to compete with the major names in drill pipe manufacture these firms will want the credibility that third party inspection firms can provide, so that is another area of the Tuboscope business I expect to grow," explains Dyer.

Local manufacturing

VAM Drilling, part of the Vallourec Group, is a fully integrated provider of drillstem products, and has recently stamped its presence on the Middle Eastern market with a series of acquisitions, including Pro Tools, and the D-PAL manufacturing and supply centre in Jebel Ali.

The DPAL FZCO manufacturing facility located in the Jebel Ali Free Zone (Dubai, UAE), offers a large range of drill pipes to the oil drilling industry in the Middle East, where it enjoys an excellent service reputation. It has an annual production capacity of 25 000 joints.

"We offer a complete range of high-performance products and services for the toughest drilling applications, including drill pipe, heavy weight, drill collars, accessories and performance drilling systems," says Anthony Monnet, regional manager, VAM Drilling.

"For the local market VAM Drilling has equally supplied drill pipe from Europe, the USA and now the Middle East. Thanks to its new Drill Pipe and BHA manufacturing facilities, VAM Drilling Middle East FZE is now capable of supplying its regional clients with full package API and Premium proprietary products with short lead times and proximity services," says Monnet.

The acquisition of DPAL is in line with VAM Drilling's strategy to be closer to our clients and to optimize our offer: short lead times, improved responsiveness by acting local,and overall optimized services. VAM Drilling takes full advantage of its vertical integration with the Vallourec Group to provide guaranteed quality every time.

 "We are very pleased with the equipment and layout of the new VAM Drilling Middle East facility. As is generally the case in any acquisition, once we have fully realised the capabilities of the facility we have made the necessary changes to ensure that we meet the level of quality demanded by VAM Drilling throughout the world."

 Many drilling environments and well profiles encountered in the Middle East require high sour service resistant grades, high-torque and fatigue resistant drill pipe as well as performance drilling solutions. "These demands are driven by the regional National Oil Companies' needs for new reservoirs to feed growing regional gas production. VAM Drilling's innovation strategy and service oriented development is built to achieve these targets.

Though business is largely dependent on drilling activity, which has been suppressed across the world in the last year, Monnet says that the acquisition has been completed in a timely manner in order to capitalise on anticipated growth.

"Regional drilling activity has not yet fully recovered, although during the 1st quarter of this year we have seen major oil companies start to move forward on highly challenging and long term projects which clearly indicates their confidence in the future," he concludes.

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