Sarah Belfield - Reporter and writer, freelance

s a r a h b e l f i e l d

reporter & writer, freelance

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SMART DRILL RODS HIGH IN FIBRE

(Australian Mining, November 2006)

WORD could be out in December on whether the Australian Coal Association Research Program (ACARP) will partly fund a proposed two-year collaborative project between CSIRO and industry that sets out to road-test fibre composite drill rods.

The project will see if non-magnetic drill rods — conventionally made of metal — can be successfully replaced by fibre composite rods.

According to CSIRO Exploration and Mining researcher Dr Philip Teakle, who will take part in the proposed work, conventional non-magnetic rods are used to house sensors behind the drill bit, such as magnetometers.

The sensors allow drillers to deduce how drilling is progressing.

For instance, measurements of the Earth's magnetic field provide details about drilling direction.

But a drawback to using conventional non-magnetic rods is they don't permit sensing of electromagnetics, Teakle said.

If Teakle and his group are successful with the work, electromagnetics sensors could be part of the picture. He said the eventual set-up might involve the first three drill rods being made of fibre composite, with the remainder of the drill string using conventional steel rods.

"Those three rods would house the direction-sensing equipment and other equipment that you could put in to tell you more about what you're drilling through — so you're doing a bit of exploration and drilling at the same time," Teakle told Australian Mining.

He said that depending on the composite material chosen, fibre composite drill rods could end up being two or three times more expensive than their plain metal counterparts. However, when compared with non-magnetic metal rods, a transition to fibre composite rods might at worst involve "replacing an expensive item with an expensive item".

Costs would not be great if only three composite rods were used, Teakle said.

"I think if it's successful, the extra value you would get and the increased accuracy you'd get in your drilling would far outweigh any additional capital outlay."

Teakle thought that if ACARP funding was not forthcoming, the proposed project would still receive some support from industry. If this were the case, "I think we would listen very closely to what they [industry] see as the main priorities."

While his group had its own research interests, "we do want to do things that are relevant and would have an immediate impact".

He said the estimated total project cost was about $650,000 over two years, with about $240,000 being sought from ACARP.

The rest would be supplied by industry and CSIRO.

Once begun, the proposed project will kick off a wider five-year program on fibre composites research "that will hopefully keep on going if we produce some good results in those five years", Teakle said.

Another near-term application being looked at is the use of fibre composites to reduce drill rod weights. Teakle said his group estimated it could halve the weight of drill rods by making them out of high-strength fibre composite material instead of the steel currently used.

This would have ramifications for the incidence of cumulative shoulder, elbow and back injuries in underground drillers, who are manually handling drill rods currently weighing about 25 kilograms.

Surface drilling might also benefit from lighter drill rods, according to Teakle.

He said his industry contacts tell him longer, more horizontal holes are being drilled nowadays. It meant a heavy string of drill rods created friction at the bottom of the hole.

"If you can have a much lighter drill string, then you can have it almost floating in the water or the mud that they use for drilling. Frictional forces are greatly reduced, so when you push on the end of the drill string, you get a lot more force at the bit."

Another spin-off to lighter drill rods would be less friction-related buckling of the drill string. The likely pay-off was being able to drill further.

While Teakle's group awaits ACARP's funding decision, other work has been going on.

Some modelling and theoretical analyses had been done and now drill rod design — such as how rods are to be joined together — was currently on the table.

Something else snaring the researchers' attention was the "intriguing idea" of a continuous coil of fibre composite rods.

"So you don't screw the rods together at all, you just have a composite pipe that's wound around a drum. You just unwind it as you drill into the ground."

Teakle said this was being done already with steel tubing, but he understood there was a limit to the number of unwrapping and wrapping cycles the metal could withstand.

Because fibre composite can flex more than steel — and because of superior fatigue properties — a composite coil might fare better for longer periods.

One avenue Teakle also identified but described as more futuristic, was the embedding wires, optical fibres, or sensors in rod walls during their manufacture. He said such a development wouldn't interfere with the flow of water or cuttings, but would help solve the challenge of getting information from near the bottom of the hole back to the surface.

Drillers would also have more information about what's occurring downhole if instruments were placed along the drill string.

Teakle said drillers currently took actions such as pushing harder or easing back largely by long experience and by inferences based on what they can sense back on the surface. But if along-string sensors indicated, say, the hole had collapsed halfway down, then drillers could take measures to reduce the risk of the string breaking or worse.

"Some people believe that's the future of drilling," he said.

One difficult task to complete first was finding a way of joining separate rods so that lengths of wires linked up.

"That's a really hard problem that quite a few people have worked on," Teakle said. He said creative thinking would be needed to solve it. Alternatively, a solution may be to take the continuous coil route.

Another potential spanner in the works, this time more generally, was that fibre composites don't tolerate rough handling as well as steel.

Teakle, a mechanical engineer by training, said the properties of metals were uniform in all directions, whereas the strength and stiffness of fibre composites depended on which way the fibres ran.

But Teakle didn't see this as a death knell for fibre composites.

"In fact, the directionality of fibre composites can be a great advantage, as the properties can better match the direction of the loads, which allows less material to be used," he said.

He described the field of fibre composites as one he expected would grow. He thought it had a long way to go given people were still "waking up to the possibilities and finding new applications", even though some composite materials had been around for decades, as was the case for glass fibre.

Assuming fibre composites prove themselves up to the task, the prospect of improved drilling should put smiles on faces on both sides of the drilling industry's pay checks.

Drillers may find themselves more in control of their drilling than ever, and employers may not lose quite so much sleep over how to find and recruit drillers with 30 years of experience — who are still in the industry.

"They always say that's one of the biggest challenges in drilling is retaining experience," Teakle said.

"If you can get better information, then you can have less experienced drillers still making good decisions.

"Also, another model is to have experienced drillers monitoring what's going on over multiple rigs ... They could be in a control room. They could be almost anywhere in the world."

s a r a h b e l f i e l d reporter & writer, freelance

About Services Clips Ideas Contact	Sample clip SMART DRILL RODS HIGH IN FIBRE (Australian Mining, November 2006) WORD could be out in December on whether the Australian Coal Association Research Program (ACARP) will partly fund a proposed two-year collaborative project between CSIRO and industry that sets out to road-test fibre composite drill rods. The project will see if non-magnetic drill rods — conventionally made of metal — can be successfully replaced by fibre composite rods. According to CSIRO Exploration and Mining researcher Dr Philip Teakle, who will take part in the proposed work, conventional non-magnetic rods are used to house sensors behind the drill bit, such as magnetometers. The sensors allow drillers to deduce how drilling is progressing. For instance, measurements of the Earth's magnetic field provide details about drilling direction. But a drawback to using conventional non-magnetic rods is they don't permit sensing of electromagnetics, Teakle said. If Teakle and his group are successful with the work, electromagnetics sensors could be part of the picture. He said the eventual set-up might involve the first three drill rods being made of fibre composite, with the remainder of the drill string using conventional steel rods. "Those three rods would house the direction-sensing equipment and other equipment that you could put in to tell you more about what you're drilling through — so you're doing a bit of exploration and drilling at the same time," Teakle told Australian Mining. He said that depending on the composite material chosen, fibre composite drill rods could end up being two or three times more expensive than their plain metal counterparts. However, when compared with non-magnetic metal rods, a transition to fibre composite rods might at worst involve "replacing an expensive item with an expensive item". Costs would not be great if only three composite rods were used, Teakle said. "I think if it's successful, the extra value you would get and the increased accuracy you'd get in your drilling would far outweigh any additional capital outlay." Teakle thought that if ACARP funding was not forthcoming, the proposed project would still receive some support from industry. If this were the case, "I think we would listen very closely to what they [industry] see as the main priorities." While his group had its own research interests, "we do want to do things that are relevant and would have an immediate impact". He said the estimated total project cost was about $650,000 over two years, with about $240,000 being sought from ACARP. The rest would be supplied by industry and CSIRO. Once begun, the proposed project will kick off a wider five-year program on fibre composites research "that will hopefully keep on going if we produce some good results in those five years", Teakle said. Another near-term application being looked at is the use of fibre composites to reduce drill rod weights. Teakle said his group estimated it could halve the weight of drill rods by making them out of high-strength fibre composite material instead of the steel currently used. This would have ramifications for the incidence of cumulative shoulder, elbow and back injuries in underground drillers, who are manually handling drill rods currently weighing about 25 kilograms. Surface drilling might also benefit from lighter drill rods, according to Teakle. He said his industry contacts tell him longer, more horizontal holes are being drilled nowadays. It meant a heavy string of drill rods created friction at the bottom of the hole. "If you can have a much lighter drill string, then you can have it almost floating in the water or the mud that they use for drilling. Frictional forces are greatly reduced, so when you push on the end of the drill string, you get a lot more force at the bit." Another spin-off to lighter drill rods would be less friction-related buckling of the drill string. The likely pay-off was being able to drill further. While Teakle's group awaits ACARP's funding decision, other work has been going on. Some modelling and theoretical analyses had been done and now drill rod design — such as how rods are to be joined together — was currently on the table. Something else snaring the researchers' attention was the "intriguing idea" of a continuous coil of fibre composite rods. "So you don't screw the rods together at all, you just have a composite pipe that's wound around a drum. You just unwind it as you drill into the ground." Teakle said this was being done already with steel tubing, but he understood there was a limit to the number of unwrapping and wrapping cycles the metal could withstand. Because fibre composite can flex more than steel — and because of superior fatigue properties — a composite coil might fare better for longer periods. One avenue Teakle also identified but described as more futuristic, was the embedding wires, optical fibres, or sensors in rod walls during their manufacture. He said such a development wouldn't interfere with the flow of water or cuttings, but would help solve the challenge of getting information from near the bottom of the hole back to the surface. Drillers would also have more information about what's occurring downhole if instruments were placed along the drill string. Teakle said drillers currently took actions such as pushing harder or easing back largely by long experience and by inferences based on what they can sense back on the surface. But if along-string sensors indicated, say, the hole had collapsed halfway down, then drillers could take measures to reduce the risk of the string breaking or worse. "Some people believe that's the future of drilling," he said. One difficult task to complete first was finding a way of joining separate rods so that lengths of wires linked up. "That's a really hard problem that quite a few people have worked on," Teakle said. He said creative thinking would be needed to solve it. Alternatively, a solution may be to take the continuous coil route. Another potential spanner in the works, this time more generally, was that fibre composites don't tolerate rough handling as well as steel. Teakle, a mechanical engineer by training, said the properties of metals were uniform in all directions, whereas the strength and stiffness of fibre composites depended on which way the fibres ran. But Teakle didn't see this as a death knell for fibre composites. "In fact, the directionality of fibre composites can be a great advantage, as the properties can better match the direction of the loads, which allows less material to be used," he said. He described the field of fibre composites as one he expected would grow. He thought it had a long way to go given people were still "waking up to the possibilities and finding new applications", even though some composite materials had been around for decades, as was the case for glass fibre. Assuming fibre composites prove themselves up to the task, the prospect of improved drilling should put smiles on faces on both sides of the drilling industry's pay checks. Drillers may find themselves more in control of their drilling than ever, and employers may not lose quite so much sleep over how to find and recruit drillers with 30 years of experience — who are still in the industry. "They always say that's one of the biggest challenges in drilling is retaining experience," Teakle said. "If you can get better information, then you can have less experienced drillers still making good decisions. "Also, another model is to have experienced drillers monitoring what's going on over multiple rigs ... They could be in a control room. They could be almost anywhere in the world."
	Copyright © 2006-2007 Sarah Belfield. All rights reserved.