1. Home >
  2. Apps >
  3. Groups >

Oil Drilling

Question asked by DavidKirschner in #Coffee Room on Jun 28, 2009
DavidKirschner
DavidKirschner · Jun 28, 2009
Rank E2 - BEGINNER
The need for oil and gas is increasing everyday, with much of the world still developing. Posted in: #Coffee Room
gohm
gohm · Jun 29, 2009
Rank A3 - PRO
will there still be petroleum by 2030?If we do not gravitate to alterante fuels, we will be forced to produce all products synthetically.
kashish0711
kashish0711 · Jun 29, 2009
Rank C1 - EXPERT
gohm
will there still be petroleum by 2030?If we do not gravitate to alterante fuels, we will be forced to produce all products synthetically.
There is enough oil for world for decades
but the main problem is that the demand will increase much higher than the rate with which is is supplied.

It is believed that there will be a peak oil situation when the oil supply will be maximum and after that there will be a steep decline in oil manufacturing rate in comparison with the demand.

and researchers say that this situations will be reached in max 10 years.


but hey I have a good good news for you guys. 😀

Ice on fire: The next fossil fuel


[​IMG] [​IMG]

DEEP in the Arctic Circle, in the Messoyakha gas field of western Siberia, lies a mystery. Back in 1970, Russian engineers began pumping natural gas from beneath the permafrost and piping it east across the tundra to the Norilsk metal smelter, the biggest industrial enterprise in the Arctic.
By the late 70s, they were on the brink of winding down the operation. According to their surveys, they had sapped nearly all the methane from the deposit. But despite their estimates, the gas just kept on coming. The field continues to power Norilsk today.


Where is this methane coming from? The Soviet geologists initially thought it was leaking from another deposit hidden beneath the first. But their experiments revealed the opposite - the mystery methane is seeping into the well from the icy permafrost above.


If unintentionally, what they had achieved was the first, and so far only, successful exploitation of methane clathrate. Made of molecules of methane trapped within ice crystals, this stuff looks like dirty ice and has the consistency of sorbet. Touch it with a lit match, though, and it bursts into flames.


Clathrates are rapidly gaining favour as an answer to the energy crisis. Burning methane emits only half as much carbon dioxide as burning coal, and many countries are seeing clathrates as a quick and easy way of reducing carbon emissions. Others question whether that is wise, and are worried that extracting clathrates at all could have unforeseen and perilous side effects.


If countries and companies are exploring the potential of clathrates only now, that's not for lack of scientific interest over the years. Research over the past two decades has shown that the energy trapped in ice within the permafrost and under the sea rivals that in all oil, coal and conventional gas fields, and could power the world for centuries to come. Oil and gas companies have been slow to catch on, however, believing methane clathrates to be unreliable and uneconomical. Feasibility studies and the diminishing supplies of conventional natural gas are changing that, making commercially viable production realistic within a decade, says Ray Boswell, who heads the clathrates programme at the US Department of Energy.


"Just a few years ago no one was thinking about clathrates as an energy source," Boswell says. "Now there is a great deal of interest in them." It is not just the US. Canada, China and Norway are entering the race too. The governments of Japan and South Korea have given the green light for full-scale production. The first intentional commercial exploitation may come as early as 2015.


So what are methane clathrates, and where do they come from? As with all natural gas, the story starts with rotting plants. As these plants decay, they release methane, which permeates through porous rocks underground. If the conditions where the methane ends up are just right - temperatures close to 0 °C and pressures of roughly 50 atmospheres - ice crystals form that trap the gas in place.


In practice, these conditions mostly occur within and underneath permafrost and beneath the seabed on continental shelves, usually at ocean depths of 200 to 400 metres, although clathrates have also been known to appear on the seabed. In 2000, a 1-tonne chunk of the stuff was scooped up by fishermen off Vancouver Island in British Columbia. They hastily dumped the hissing mass back into the ocean.


Fishermen scooped up a hissing mass of the stuff - and hastily dumped it back in the ocean





Until recently, these deposits escaped the serious attention of energy companies. Engineers stumbled on clathrates from time to time while drilling for conventional reserves of oil and gas, but they were mostly viewed as an irritant that caused blowouts or blocked pipelines.


That view changed with studies showing that the gas is often present at a given site in concentrations of 50 per cent or more in ice's pore space - values similar to the prevalence of natural gas in traditional sources - in layers of clathrate hundreds of metres thick. What's more, in its constricted surroundings the gas is compressed to 160 times its density at atmospheric temperature and pressure, making for vast quantities of it when released.


These revelations made clathrates a potential gold mine that countries and energy companies are now eagerly prospecting. In 2007, a US project found clathrate reserves in Alaska with 80 per cent of the ice's pore space packed with methane. Tim Collett, a clathrate specialist at the US Geological Survey who was part of the team, says there may be reserves all along the Alaska north slope, including beneath existing oil installations at Prudhoe Bay and, alarmingly for environmentalists, the Arctic National Wildlife Refuge.


Collett estimates there is between 0.7 and 4.4 trillion cubic metres of methane clathrate in Alaska alone. Even the low end of that range could heat 100 million homes for a decade. "It's definitely a vast storehouse of energy. But it is still unknown how much of the volume can actually be produced on an industrial scale," he told a meeting of the American Chemical Society at Salt Lake City, Utah in March this year.


That's not the only reserve of interest. In 2004, a German and Chinese team found methane venting from the seabed off the coast of Taiwan in the South China Sea, and in 2006 Indian researchers found a layer of methane clathrates 130 metres thick off its east coast in an area known as the Krishna-Godavari basin. Collett calls these "one of the world's richest marine gas clathrate accumulations".


Estimates vary, but conservative figures place global reserves at roughly 3 trillion tonnes of previously untapped carbon - more than is trapped in all the other known fossil fuel reserves put together, says Klaus Wallmann of the Leibniz Institute of Marine Science in Kiel, Germany.


That would last about 1000 years if we continue to use natural gas at the current rate, estimates Collett. Even if the methane from clathrates replaced all fossil fuels, and not just gas, it would still last for at least 100 years. But with this methane held in fragile ice crystals and buried deep within the Earth, can it be exploited safely and economically?


Until recently, there were two methods of extracting methane from clathrates that were considered feasible. One is to drill a hole into the clathrate deposit to release the pressure, allowing the methane to separate out from the clathrate and flow up the wellhead. The second is to warm the clathrate by pumping in steam or hot water, again releasing the methane from its icy matrix.


In 2002, Canadian, American, Japanese, Indian and German researchers tested both techniques in the field, at a drill site called Mallik on the outer extremity of the Mackenzie river delta in the Canadian Arctic. Both were successful, but the energy costs of the heating method nearly outweighed the energy gained from the methane released, making depressurisation the more attractive option.


The potential of depressurisation was confirmed in March 2008, when Canadian engineers led by Scott Dallimore of the Geological Survey of Canada used the technique to tap 20,000 cubic metres of methane gas over six days from a deposit located 1 kilometre beneath Mallik.


Similarly, in 2007, South Korea exploited depressurisation to extract methane clathrate from the Ulleung basin in the Sea of Japan. Officials believe reserves there could meet the country's gas needs for up to 30 years, and they plan to begin production by 2015. Meanwhile Japan, another country with limited fossil fuel reserves, has found up to 50 trillion cubic metres of clathrate south-east of Honshu Island in the Nankai trough - enough to supply the country with natural gas for centuries. In March 2008, the Japanese cabinet pledged to begin production by 2016.


So methane clathrate extraction seems to be imminent, in Asia at least. Whether it is desirable is another matter. Some argue that the world shouldn't be tapping a new fossil fuel while we are pledging to build a low-carbon economy. Methane might be less carbon intensive than fuels such as coal, but switching to methane would not help countries to reach ambitious targets for reducing carbon emissions of up to 80 per cent by 2050.


To make matters worse, the methane itself could exacerbate global warming if it starts leaking from the reserves. Methane is, molecule for molecule, 20 times as powerful at warming the air as CO2. Rising sea temperatures could melt some undersea clathrate reserves even without extraction projects disturbing them, triggering a release of this potent greenhouse gas. A decade ago, Peter Brewer of the Monterey Bay Aquarium Research Institute in Moss Landing, California, showed how clathrates on the seabed just off the coast of California disappeared after an El Niño event raised ocean temperatures by 1 °C.


Exploitation of clathrate reserves might exacerbate this problem, but it could also have far more immediate adverse effects. Clathrates exist in a delicate balance, and the worry is that as gas is extracted its pressure will break up neighbouring clathrate crystals. The result could be an uncontrollable chain reaction - a "methane burp" that could cascade through undersea reserves, triggering landslips and even tsunamis. "Extraction increases the risk of large-scale collapses, which might have catastrophic consequences," says Geir Erlsand from the University of Bergen in Norway.


Disturbing the clathrates' delicate balance might unleash an uncontrollable 'methane burp'



Evidence that such events have happened in the past comes from the Storegga slide, a landslip on the seabed off western Norway about 8000 years ago. A 400-kilometre stretch of submarine cliff on the edge of the continental shelf collapsed into the deep ocean, taking with it a staggering 3500 cubic kilometres of sediment that spread across an area the size of Scotland. The result would have been a tsunami comparable to the one that devastated parts of south-east Asia in 2004.


The naval researchers who first discovered the remains of the slide in 1979 assumed it was the result of an earthquake. Perhaps it was initially, but Jürgen Mienert of the University of Tromsø in Norway has found that the slumped area was also a hotspot for methane clathrates. The sheer number of cracks and giant pockmarks on the seabed, carbon-dated to the time of the slide, suggest billions of tonnes of methane must have burst out of the cliff along with the sediment, a possible trigger for the landslip. The resulting explosions would have turned even a minor slip into a major disaster.


Sinking carbon

The Storegga slide is not the only incident of this kind. The ocean floor from Storegga to Svalbard is full of pockmarks that might have been caused by similar clathrate-driven landslides, says Mienert. He says we will see more of these events in the future. "Global warming will cause more blowouts and more craters and more releases," he warns.
Other engineers believe claims that clathrate extraction poses a risk are little more than scare stories with little supporting evidence. Wallmann claims that the Chinese and Indians in particular are "afraid that the west wants to prevent them from rapid extraction of methane clathrate".
There might in fact be a safer way of tapping clathrates which, if successful, could quash the criticisms. Since other gases can also form clathrates, it should be possible to pump one of these gases into the crystals to displace the methane. Carbon dioxide would be an ideal candidate, says Ersland - the resulting crystal is even more stable than methane clathrate, meaning another greenhouse gas would be stored out of harm's way.


Ersland has already demonstrated his technique in the lab. In joint research with the energy company ConocoPhillips based in Houston, Texas, he replaced methane with CO2 in artificial clathrate crystals. The exchange was rapid and did not damage the clathrate structure, making it the safest way to extract the methane yet found (Chemical Engineering Journal, DOI: 10.1016/j.cej.2008.12.028). Substituting methane with CO2 "will increase the stability of the reservoir sediments as well as maintaining the clathrates in their solid state", Ersland says.


The acid test will be an experiment planned for January next year. ConocoPhillips intends to pour liquefied CO2 down a borehole into the Alaskan north slope's clathrate deposit. If all goes well, the CO2 will fill the clathrate crystals and the displaced methane will shoot up the wellhead to the surface. The method could be both a safe way of capturing the methane and an environmental argument for pursuing the goal - the clathrate structures would be acting as a carbon sink.
It is an intriguing possibility. Sooner rather than later, burning fossil fuels like coal and natural gas will only be acceptable if the CO2 emissions are captured and stored. Right now, there is a rush to develop a practical system for capturing and burying billions of tonnes of CO2 underground per year.


So far, the focus has been on old oil wells, salt deposits and even old coal mines. The big problem is that the huge infrastructure required to dispose of the CO2 may quickly make burning fossil fuels uneconomic compared with alternatives like solar, wind or nuclear power. Disposing of CO2 down the same pipe used to bring up more fuel could be the answer.


[​IMG]


SOURCE: Ice on fire: The next fossil fuel - environment - 24 June 2009 - New Scientist


😀
kashish0711
kashish0711 · Jun 29, 2009
Rank C1 - EXPERT
I found a great reply at a website explaining the technology needed to extract it commercially.

Source: TheEEStory.com: Methane Clathrates


REPLY:
I was surprised to see Methane Clathrates as a heading in the EEStor blog site. Before I retired I worked in the oil field on shore and off. We called it methane hydrate but it's the same thing. Methane and water under pressure ~900 psi and cool temperatures ~+60 deg F form a hydrate. In the transportation of methane in a pipeline, natural gas, the gas must be kept very dry or it will form the hydrate in cool weather and plug the pipeline. I've had some in my hand and it looks a little like ice but it's not very cold and it fizzes slowly. Soon you just have a wet hand. Under the oceans of the world every thing that had been alive in the water dies and sinks. This organic matter is mixed with the dirt from the atmosphere, the rivers and shores and builds up on the sea floor. Here the organic matter decomposes and releases, among other things, methane and CO2. Just like those methane digesters you read about in Mother Earth News. In the deep ocean it's cold, just above freezing, below 1800' the pressure is high enough to form Methane Clathrates. While burning methane still produces CO2 it's better than coal. Until we develop a cost effective method of storing energy, solar and it's derivatives, like wind, are just a crutch. For the short term using methane for transportation and electricity production is better than oil and coal. (Build more nukes!)
How to get it? Looks easy, much of it is near or on the surface of the sea floor. Careful! the natural production is ongoing. trapped under the hydrate is gas, methane and CO2. When you disturb the solid the gas will break up the formation and tend to lift the mass upward. What would this do? If you are working on the vessel above the mixture of gas and seawater is less buoyant than just the water. As you sink rapidly and violently into the sea you think Oops. But that is the small problem. The quantity of gas may be in the billions or trillions of cuft, or not. An ignition source and it might be like a fair sized H bomb, or maybe just a Hollywood flash. You never know. Methane is about 23 times stronger as a greenhouse agent than CO2. A few big accidents could make NY, NY a nice dive site. I'm not saying don't, just be careful.

Back to how to get it. First study the site, find any free gas and use a conventional gas well. When the free gas is removed use a larger pipe, we call them casings, with a device on the end to cut the hydrate and at the same time inject a small amount of methane partway up the caseing. As this gas floats up inside the caseing it will expand and move the water along with it. This method is used in oil wells to lift oil and water from the well, called a "gas lift". Very efficient. Once the hydrate enters the casing and is lifted the pressure will drop and the water will be warmer at shallower depths. The hydrate will start to decompose and that gas will provide all the energy needed to continue. A hydraulic motor, called a mud motor at the bottom can power the cutting tool, if one is needed, Once the gas lift starts it will have a great deal of energy. There will be a need for a propulsion system at the bottom to move the end of the pipe from place to place and the flow of water can provide that energy too. The technology needed for this operation exists now.

You must log-in or sign-up to reply to this post.

Click to Log-In or Sign-Up