June 30th, 2010
Deepwater drilling rigs are fitted with billions of dollars-worth of high tech well equipment. Pipe flanges and other fittings are manufactured from super duplex and other high-grade alloys. The drilling crews receive intensive training in all aspects of well-head management, from checking pipe fittings for leakage, to extensive testing of redundant systems during drilling operations.
Most deep water drilling is done by semi-submersible oil-rigs, mobile vessels whose job it is to drill gas and oil wells, and install subsea production systems. All the materials – pipes, flanges, wellhead equipment etc is shipped out as it is needed, and a cutting-edge remote positioning system ensures exact control over the platform’s movements from one oil field to the next.
Yet for all this, things can go wrong. Deepwater Horizon suffered a catastrophic blowout while production castings were being cemented into place – ironically, to make the well safe prior to the rig being moved. The rig had a number of safety devices, designed to shut off the pipe at one of the flanges if a blowout was detected. This didn’t happen – somehow, the valve shut-down switch was bypassed. In other words, there was a failure of the well control system.
Accidents of this kind are generally down to either human error or systems failure. But let’s not forget that deepwater drilling is in its infancy. When you look at the number of oil platforms, wells, and processing plants there are, the number of accidents is actually very low.
We at Chemipetro continue to provide high quality pipe fittings to the gas, oil and petrochemical industries. We aim to keep things as safe as possible – for both the workers and the environment.
Tags: Flanges, Pipe Fittings, Pipe Flanges, pipe joints
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June 27th, 2010
Pipe fittings and flanges on today’s oil rigs and deep-water wells are routinely manufactured from high strength and corrosion-resistant alloys. We at Chemipetro supply super duplex pipe fittings across the industry.
High quality alloys means minimal risk of leaks due to flange failure. However, it also means that if a big blow-out does occur, it’s more likely to happen at the well head than the seams.
A blow-out event of any kind is a disaster. Not only can lives be lost, but billions of gallons of crude oil can contaminate the environment. Thus it’s essential that safety devices are fitted that not only give early warning of impending blow-outs, but can seal the well off at underwater flanges if such a blow-out occurs.
Brazilian and Norwegian regulators have such a device fitted as standard on their underwater rigs. Called an acoustic switch, it cuts in the moment there’s an underwater spill. US rigs are not fitted with such a device. It’s now being suggested that, had they been, the recent tragic events off the coast of Louisiana need not have happened.
The acoustic switch is, it must be said, a last-ditch device when all else has failed. Remotely triggered by crew members, it operates an underwater valve at one of the pipe flanges, shutting down the damaged well and preventing an explosion or oil leakage. If the platform has to be evacuated, it can be triggered from a life raft.
US regulators disagree that the device is necessary, raising questions about its effectiveness, and pointing out that they have their own safety devices to shut down rigs.
Tags: Flanges, Pipe Fittings, Pipe Flanges, Super Duplex
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June 24th, 2010
Duplex steels have a mixed ferrite and austenite microstructure, to which various other metals such a molybdenum are added to increase mechanical strength and corrosion resistance. Duplex and super duplex pipe fittings don’t conform to one exact composition. There are several grades, which vary in corrosion resistance.
While it may seem odd to select a duplex steel with higher corrodibility, it must be remembered that selecting alloys for pipe flanges is often a juggling act. Slightly higher corrodibility may be offset by superior mechanical strength, so a steel of this grade may be the choice if you are working at high pressures, but in a fairly neutral environment.
Duplex steels are graded according to their alloy content. Super Duplex steels have the highest level of alloy, and therefore the lowest resistance to crevice corrosion and pitting. Pitting resistance of steel is measured by its PRE (pitting resistance equivalent).
Ordinary austenite and ferrite stainless has a PRE of 17 – 18%. s1803 duplex has a PRE of 34% – the same as N08904 austenite steel, although the latter has poorer resistance to acids, and is more sensitive to stress-corrosion cracking. The highest PRE is achieved with S32750 and S32760 super duplex – both of which we supply at Chemipetro. They differ in that S32750 has added tungsten to increase pitting resistance, but both have a PRE of at least 43%.
The high chromium content of super duplex steels makes them the ideal choice for acidic and caustic environments. Duplex and super duplex pipe flanges are widely used in chemical, petrochemical, pulp and paper and marine environments, often replacing high nickel super-austenitic steels such as S31254.
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June 21st, 2010
Duplex and super duplex steels are widely used in the petrochemical industry, as well as oil and gas refineries and marine rigs. They are prized for their superior corrosion-resistance, strength and durability.
We at Chemipetro are increasingly supplying duplex flanges and pipe fittings to demanding 21st century environments, such as deep-water oil wells and petrochemical plants. However, duplex steels were actually developed more than 70 years ago, for the Swedish paper industry.
The first generation duplex steels were specifically designed to be resistant to the chemical process fluids used in the paper pulp industry, such as chloride-enriched cooling waters. The second generation alloys now in use have improved upon this, having superior stress and pressure-resistant qualities, and enhanced resistance to pitting. The chemicals used in the modern petrochemical industry are far more pressurised and corrosive than the Swedish pulp mills were.
Duplex is so-called because it has a mixed microstructure of roughly equal proportions of austenite and ferrite. To this, chromium, nickel and molybdenum are added in varying amounts to improve resistance to pitting and weldability. Super duplex steels were developed in the 1980s in response to the increased use of highly corrosive and high-pressure industrial environments.
The phrase, “the whole is better than the sum of the parts” could have been written for duplex. Its resistance to stress-cracking through corrosion is superior to type 316 steel alloys, and its mechanical strength is roughly double that of singular austenitic steel. The one criticism of duplex pipe flanges has been embrittlement at extreme temperatures. However, this is being addressed by development of cool-welding techniques, and alloys that withstand sub-zero and arctic conditions.
Tags: Duplex, duplex pipe flanges, Pipe Fittings, super duplex steels
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June 18th, 2010
We know that deep drilling causes problems for pipe flanges and other components. Heat, pressure and corrosion all combine to cause cracking, fatigue and failure unless the very best alloys are used. Yet even super duplex has a finite existence. In order to drill deeper, we first must know what we’re up against.
In the Gulf of Mexico are the world’s deepest untapped oil reserves, at the Tiber Oilfield. Already home to the deepest oil well in the world, BP now wants to explore deeper still – beyond the massive salt accumulations known to distort seismic waves, and way beyond the 6.7 miles drilled already, but will the pipe flanges take the pressure?
Much of what has been discovered so far has been down to the world’s deepest borehole – the Kola Superdeep, in Russia. Opened in 1972, it has revolutionised our knowledge of the Earth’s crust – which is a far more hostile place than geologists give it credit for. For example, at 7.5 miles down, drills encounter temperatures of 180°C, and pressures so high the rocks become “plastic” – solid to the touch, yet flowing like thick mud around the drill hole. Going past this point is impossible, with current technology.
The drilling apparatus Kola employs is very different to the rotating shafts of conventional deep-drilling rigs. Only the drill bit at the very end rotates, achieved by forcing drilling mud through the drill centre. As you can imagine, all the pipe fittings are specially made.
We at Chemipetro realise that few pipe fittings are as unusual as those at the Kola Borehole. Nonetheless, we will happily customise pipe flanges and fittings for your own projects.
Tags: Flanges, Pipe Fittings, Pipe Flanges, Super Duplex
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June 15th, 2010
Events in the Gulf of Mexico have brought home to us the hazards involved in deep water, offshore drilling. Yet it’s easy to forget that, all over the world are deep – sometimes miles deep – oil and gas wells performing perfectly efficiently. All the same, the pipes and flanges are regularly checked for signs of damage, and numerous sensors are installed to warn of possible geothermal trouble that might be brewing.
We know that deep drilling causes immense temperature and pressure stresses, as well as being a highly corrosive environment. This is why super duplex and similar high-strength alloys are widely used in deep water rig flanges.
Much of the information we have on the deep drilling environment comes from studies carried out at the Kola Borehole, in Russia. What’s been discovered has turned our dependable planet’s crust into a hostile, alien world.
Before the Kola hole was dug, researchers thought the crust was a benign series of rock interfaces. The heat and pressure started at the mantle, they thought. What they found instead was rock metamorphosed by heat and pressure so intense, it had forced out oxygen and hydrogen molecules to form water. Yet they also found intact fossil shells.
A little further, the rock turned to plastic, and the drill was so hot – way above the expected 100°C – that it had reached its tolerance. When it was withdrawn, the hole closed up. Yet the Earth’s crust had hardly been pricked.
The super duplex pipe flanges we supply at Chemipetro can stand up to most environments, although we’re not sure about changes to the laws of physics.
Tags: Flanges, pipe joints, Super Duplex, super duplex pipe fittings
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June 12th, 2010
Crude oil production is a highly corrosive environment, on top of which you have pressure and heat effects as well. The stress on pipe fittings and flanges increases the deeper you go – and today it’s not unusual to find offshore wells being drilled 4 or 5 miles down.
The recently lost offshore rig Deepwater Horizon was no ordinary drilling rig. She was a semi-submersible, ultra-deep water mobile offshore drilling unit (MODU). Her purpose was to specifically drill deep oil wells, production then being handled elsewhere. Like the Titanic, she was considered unsinkable. The use of an advanced dynamic positioning (DP) system saw to that. Remotely monitored and controlled, she could be accurately positioned anywhere in the ocean – and if a storm or underwater turbulence was detected, she could simply be placed out of harm’s way, till the danger was over.
The cause of the Deepwater explosion is believed to be a sudden pressure blowout from gases released during drilling – something the dynamic positioning equipment and maintenance crew could not have foretold. Faulty pipe fittings and computer technology didn’t let the Horizon down – the force of nature did.
Deepwater Horizon had a short, but impressive history. 7 months prior to her tragic loss, she had sunk the world’s deepest oil well. At 6.7 miles deep, it was exactly a mile shorter than the Kola Superdeep Borehole. Located in Russia, it’s the world’s deepest man-made hole.
The deeper you go, the more you ask of your pipe fittings. And today, we’re drilling deeper all the time. We at Chemipetro supply high quality duplex and super duplex steel pipe flanges and other fittings, built to withstand the most hostile environments in the world.
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June 8th, 2010
There are rich oil and gas fields still to be exploited; the trouble is that they’re a long way underground – or rather, under ocean. The pipe fittings, tubing, flanges and other components of deepwater installations must evidently be manufactured to incredibly high levels of pressure and temperature resistance. But just how high do these standards have to be? How deep is deep?
Prior to her untimely end, the ultra-deepwater, semi-submersible mobile oil rig Deepwater Horizon had drilled the deepest oil and gas well in history. Located in the Tiber oilfield, the well was a staggering 35,055 ft (6.6 miles) deep, only 4,132 ft of which was seawater. This is close to the 40,230 ft (7.6 miles) of the Kola Borehole, the deepest hole in the world.
The aim of the USSR Kola borehole was not to drill for oil, but to explore the mysterious, hot place where crust and mantle meet – the Mohorovičić discontinuity, or “Moho.” Sunk in 1972, the borehole is still an important geological resource today, although the Russians never quite reached their Moho, they got pretty close.
They uncovered some surprising new facts. For example, at a relatively shallow depth of 2 – 4 miles, the rock was discovered to be under incredible heat and pressure – so much so that hydrogen and oxygen were being squeezed out, creating water. Another surprise was the discovery of fossils at 6 miles down – proof of deep oil reserves.
Kola’s drills, pipe fittings and flanges were all specially designed, and continue to be in service today. We at Chemipetro apply the same high levels of craftsmanship to our own flanges, ensuring you get long life and productivity.
Tags: Flanges, Pipe Fittings, Pipe Flanges, tubing fittings
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June 5th, 2010
The pipe fittings we supply at Chemipetro are manufactured to withstand some of the earth’s most hostile environments. As mankind attempts to wring every last drop from the earth’s crust, so the wells get deeper – and the costs get higher. This was proven to tragic effect in April 2010, when the Deepwater Horizon exploded and sank, pipe flanges and all, to the bottom of the ocean, taking 11 crew members with her. The cost to marine life has been immeasurable.
Despite state-of-the-art rig technology and super duplex pipe flanges, deepwater drilling is in its infancy. The more extreme it becomes, the more dangerous it becomes too. When Deepwater blew, it was through a combination of factors, chief among which was the under-estimation of the power and speed of the earth to strike back.
Deepwater Horizon was the jewel in BP’s crown. 7 months’ previously, she had successfully sunk the deepest oil well in the world. But while a casing was being cemented – ironically, to safely shut off the well so the Deepwater could be moved –an unprecedented and abnormal pressure build-up occurred, rising and expanding in a terrifying burst of energy. Although the rig was fitted with cutting-edge blow-out preventers, or BOPs, the explosion occurred with such speed and finality that they were overridden.
It’s been suggested that back-up devices could have prevented the explosion – though this seems doubtful. What is certain is that not one factor of the blowout could be attributed to the construction of Deepwater Horizon herself. From the state-of-the-art dynamic positioning system, to the pipe flanges that proudly withstood the full force of the blowout, she was an inspirational work of art.
Tags: Pipe Fittings, Pipe Flanges, pipe joints, super duplex pipe flanges
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June 2nd, 2010
The Deepwater Horizon tragedy needs no introduction. Yet this was no ageing oil platform with rusting flanges and leaky pipe fittings. A state-of-the-art, dynamically-positioned, semi-submersible oil rig, she was the jewel in BP’s crown. Upgraded with cutting-edge technology in 2002, she drilled the world’s deepest ever oil well, in September 2009. Yet just a little over 6 months later, she was blown apart by the worst explosion the US oil and gas industry had ever seen. Several workers lost their lives, and the effect on the marine environment has been immeasurable.
Despite the fact that production casing pipes were being run and cemented at the time of the explosion, the cause was not, so far as anyone is aware, connected to the pipe flanges. The bore was due to be plugged, ready for later completion as a subsea producer while the Deepwater rig moved on to a new site. However, before this could be done, an unusual level of pressure built up in the marine riser, which rose and expanded suddenly, causing the massive blowout and loss of life which occurred.
Gas and oil are volatile and unpredictable, and the flanges and pipes used to convey them have to endure very high pressures. No matter how cutting-edge the equipment, and how well-trained the personnel are, it’s still a risky business. The truth is, the blowout was of such magnitude, and so unexpected, that for once strong pipe fittings weren’t enough.
We at Chemipetro can’t guarantee your installation won’t suffer unexpected problems however, by fitting our quality pipe flanges and fittings, we can keep unexpected failure down to a minimum.
Tags: Pipe Fittings, Pipe Flanges, pipe joints, types of pipe flanges
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