Thursday, February 28, 2013

OGPSS - An update on Russian plans and the OPEC MOMR

The Arctic is a less forgiving place than many folk care to recognize. Shell have just moved back the date on which they plan to restart drilling in the Chukchi Sea and won’t be going up there this year. At the same time, last August, Gazprom announced that the development of the Shtokman gas field off the Russian coast and also in the Arctic had been put on an indefinite delay. Yet the region still shows considerable promise. ExxonMobil and Rosneft have agreed to exploration in the Chukchi, Laptev and Kara Seas, with the latter considered as possibly having the highest potential.

Figure 1. Location of the Kara and Laptev Seas. (Google Earth)

The blocks that will be explored are South of the island of Novaya Zemlya, in relatively shallow water. They lie north of the Yamal Peninsula, and the Shtokman field is on the other side of the island.

Figure 2. The locations of the East Prinovozemelsky blocks south of the island of Navoaya Zemlya (Rosneft)

Rosneft estimates that the reserves that are recoverable are 6.2 billion tons of oil, and a total of 20.9 billion tons of oil equivalent when the natural gas content is included. The first wildcat well is scheduled to be drilled in 2015.

While Gazprom and Rosneft share access to these offshore resources, Lukoil has found a site at Khatanga Bay in the Laptev Sea where it believes that it can be successful. Despite the difficulties, the need for Russia to sustain production is forcing the companies offshore into more difficult waters, it is where the future production lies, and the Russian economy needs the income.

The February OPEC Monthly Oil Market Report notes that Chinese demand has now topped 10 mbd on a quarterly average, the highest to date and growing at 6%. The greatest increase has been in the use of gasoline. Global demand is anticipated to top 91 mbd by the end of the year. Russia is anticipated to produce some 10.42 mbd on average this year. OPEC has, however, a few caveats:
The Vankor oil field is expected to average 435 tb/d in 2013, a minor increase from the level of 410 tb/d achieved by the end of 2012. Some operators provided that new technologies will be utilized to stop natural decline. On the other hand, the supply forecast remains associated with a high level of risk, due to technical, political, geological and price factors. On a quarterly basis, Russian oil supply is expected to average 10.43 mb/d, 10.42 mb/d, 10.42 mb/d and 10.42 mb/d, respectively. Preliminary figures indicate that Russian oil production stood at 10.46 mb/d in January, steady from the previous month.
As usual it is interesting to compare the OPEC production results for the last few months, based both on the reports obtained from secondary sources, and those numbers that the individual nations provide.

Figure 3. OPEC crude production based on secondary sources (OPEC February MOMR )

It is important to note that Saudi Arabia has dropped its production by around 300 kbd or so for the last couple of months. While I suspect that this to keep markets a little tighter and thus hold prices stable, others might suggest that the may have some slight difficulty sustaining the higher numbers.

Figure 4. OPEC oil production figures as reported by the producing countries. (sources (OPEC February MOMR )

Iran continues to have a disparity of around 1 mbd between the two tables, Iraq still seems to be struggling to get over 3 mbd, and Venezuela has a discrepancy of around 400 kbd. In short, not much new.

Turning back to look for just a moment at Gazprom activities, although they have continued to keep Lukoil out of the Arctic, they have also continued to seek resources abroad. The company has acquired territory in Iraqi Kurdistan and is reported to have an 80% stake in the Halabja project with reserves of around 700 mb. The field lies on the Iranian border in the Kurdish part of the country, and Baghdad objected to the deal going forward. It might, however, help raise Iraqi overall production. Gazprom has two other projects in the region at Garmian and Shakal, and one at Badra which falls under the control of the central government.

And, still in the Middle East, Gazprom is in talks with Israel to buy LNG from the offshore Tamar field and ship it to Asia to serve markets that it cannot easily reach with its pipelines. The intent is to use a floating liquefaction plant that will take gas from both Tamar and Dalit, at the rate of around 3 million tons a year with production starting in 2017.

Gazprom recognizes that, if it is to develop Asian customers it must provide LNG and so it has begun work on an LNG plant in Vladivostock with three trains, each capable of producing 5 million tons of LNG a year, from the Sakhalin, Yakutia and Irkutsk gas fields. With production aimed to begin in 2018, the market will, again, be in the Asia-Pacific region and may be one of the reasons to accelerate production from the Kovyktinskoye field. At the present time Gazprom has brought the Zapolyarnoye up to full production, and they estimate that this will produce 20% of Russian natural gas as the field moves to be the largest producer in the country.

And, while tracking down some of the information for this post, I did find a picture of a polar bear and cub in the region that ExxonMobil is venturing into. It was taken on the island of Novaya Zemlya. Hopefully environmental concerns won't raise the same sort of difficulties in developing these sites that they have in other places further East.

Polar Bear and cub on Novaya Zemlya on the Shores of the Kara Sea (the photo is on Google Earth and was taken at the red arrow in Figure 2 by

Oh, and before I forget the Alaska pipeline continues to run below 600 kbd with an average of 577, 604 bd. for January.

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Tuesday, February 26, 2013

Waterjetting 6c - Cutting foam and testing with it.

Last week’s post discussed a simple test which helps to show not only how to compare the effect of different operating conditions (varying abrasive type, nozzle design, AFR etc) as a way of finding a possibly better and cheaper cut. It is also often handy to know when a nozzle is starting to wear out, so that different cutting operations might be scheduled to allow the nozzle to continue to work, without threatening the quality of critical product.

Figure 1. Change in the cutting depth of a jet stream, at 50,000 psi, when traversed over ASTM A108 steel as a function of the time that the nozzle had been in use.

While we have found that nozzles from a given manufacturer roughly agree in cutting performance and times before they wear out, the pattern of wear and performance change differs from one nozzle design to another. Also there is some variation in performance between nozzles even of the same design and under the same conditions.

There are also times when cuts are made without abrasive, or when the cutting/cleaning jet is hand held – what to do in those cases? Mainly we have used foam as the cutting target, set up so that the jet won’t cut all the way down through the foam all the way along the cut, so that, as with the steel, some idea of not only cutting depth but also cut quality can be seen.

Figure 2. Cuts through thick stiff packing foam. Note the rough edge at the bottom of the extracted pieces, but the good initial quality of cut that was achievable for some 14-inches.

There is a caution in cutting foam, in that some of the softer varieties are going to fold into the cut, and give a slightly inaccurate measure of true performance, although for a quick comparison to see how a nozzle is lasting that is not a real issue. When cutting thicker material, and also when going for higher quality cuts, that is, however, something that should be borne in mind.

The white expanded foam that is used as a packing material is also very easy to cut, even with the pressures that can be found with a pressure washer type of system. Thus, if you are going to clean a deck or other surface it helps to check, by swiping the jet across such a piece of material, to be sure that you have a good nozzle on the end of your lance before you start.

This may seem fairly logical, after all you just went to the hardware store and bought a new packet of nozzles. Well, as with the other nozzles we have looked at, quality is only assured after testing. In this particular case we ran as many different variety of fan nozzles as we could to see how they would perform when cutting across a piece of packing foam. It is not hard to cut packing foam with a high pressure jet. And since domestic cleaning is usually carried out at either 1,000 psi or 2,000 psi we ran tests at both levels.

Figure 3. Results from a good, top, and a poor nozzle with cuts at 1,000 and 2,000 psi. and with the foam moved through the jet at a distance of 3 inches. The number identifies the nozzle and note that at 3 inches number 18 could barely remove the top of the foam.

A fan jet is defined by the amount of water that it will allow to pass at a set pressure, and by the angle of the cone with which the jet spreads out from the orifice. In passing we found that the cone angle that the jet actually spread at was a little larger than that designated on the package.

The worst nozzle design that we found had difficulty in cutting into the foam, even at a very close range:

On the other hand the best nozzle was still able to cut the material with the nozzle held some nine inches from the foam.

Figure 4. Cutting result with the good nozzle held at nine inches above the foam target. At this distance the jet is removing as much material as the poor jet did at a 3-inch standoff.

A very typical result would have the jet fail to cut into the foam much beyond four inches from the nozzle. (I’ll use some photographs in a couple of weeks to explain in more detail why that is). And as a short editorial comment to those of you who clean around your house with a domestic unit, how many of you hold the nozzle that close to the surface? (Or at the car wash?) If you don't you are losing most of the power that you are paying for, and you are in the company of most of the students that I ran this demonstration with in my classes).

However there is one other feature to the photographs of the cuts that I would point out. Fan jets distribute the water over a diverging fan shape. But the results of the design fell into two different types, one where most of the water still concentrated in the middle of the jet, (as in Figure 4) and those where it was focused more on the side.

Figure 5. Cutting pattern with the jet streams more at the side of the flow. (arrow points), note that the two pressure cuts are on the other sides of the sample here).

The benefit of using foam is that it allows this picture of the jet structure to be easily seen, with very little time taken to swipe the nozzle over a test piece of material at the start of work, to make sure that the jet is still working correctly.

This is both an advantage and a disadvantage. Because the foam is relatively easy for a jet to cut, even at a lower pressure, this means that the cut can become more ragged with depth, where deep cutting is required.

One of the programs that we ran, some years ago, looked at how deeply you could cut into the stiff packing foam that is used in some industrial plants, where the item being packed needs to be held firmly, yet will be released easily when needed. This requires that the foam be cut to a very tight tolerance, and at the time, pieces were still being cut by hand and then glued together. (Figure 2 above)

We found that we could cut up to about a foot of material, before the small cut particles became sufficiently caught up in the cutting jet that the edge quality of the cut fell below specification. But in order to get to that depth we did have to add a small amount of a polymer to the cutting water. This helped to hold the jet more coherent over a greater distance, and also reduced the amount of particulate that got caught up in the jet, allowing the greater cutting depth.

Foam works as a simple sample to give some sense of the jet shape, where the pressures are lower. When they are higher then a stiffer material is needed, though it should still be cuttable by water without the need for abrasive. Plywood is a useful target in this case, and I will write about those tests next time.

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Friday, February 22, 2013

OGPSS - Thoughts on the Precautionary Principle

As Michael Brander tells it, in his book on the Scottish Highland Regiments, the Scottish Highlands produced, between 1740 and 1815 men for some 86 Highland Regiments who travelled around the world to strengthen the British Empire. But, towards the end of that period sheep were introduced into Scotland and the great land clearances began that replaced the crofters on the estates with the occasional lone shepherd and his flocks. Thus, by the time of the Crimean War when the Duke of Sutherland tried to raise a regiment he got no volunteers. As an old man explained to him:
I am sorry for the response your Grace’s proposals are meeting here today, so near the spot where your maternal grand-mother, by giving some forty-eight hours notice, marshaled 1,500 men to pick out the 800 she required. But there is a cause for it, and a genuine cause, and, as your Grace demands to know it, I must tell you, as I see that none else is inclined in the assembly to do so. These lands are now devoted to rear dumb animals which your parents considered of far more value than men . . . . your parents, yourself and your Commissioners have desolated the glens and the straths of Sutherland where you should find hundreds, yea thousands of men to meet and respond to your call cheerfully had your parents kept faith with them. How could your Grace expect to find men where they are not?
The anecdote illustrates that are long-term consequences to policy decisions, often not fully recognized when the original decisions are made. I was reminded of the Scottish situation as I contemplate the great race to renewable energy and natural gas, and the rapid replacement being urged for coal-fired power stations and nuclear power plants. And there are some grounds for seeing an analogy to that earlier situation.

Coal and uranium are found underground and while there is a large surface mining component to mining, as these reserves are exhausted, or embargoed for environmental or other political reasons, the need, over time will move increasingly to the development of the deeper reserves. Mines, however do not spring up overnight. Just as you cannot get a baby in a month by making nine women pregnant, so the process of discovery, raising capital, permitting and development can mean that over a decade can pass before coal is produced in commercial quantitites. And that assumes that the Administration is somewhat favorable to the idea. As a candidate, now President Obama said "If someone wants to build a new coal-fired power plant they can, but it will bankrupt them because they will be charged a huge sum for all the greenhouse gas that's being emitted."

As President he appointed Dr. Stephen Chu to head the Department of Energy, an individual who has said “Coal is my worst nightmare.”. And to follow on his statement as a candidate, the President appointed Lisa Jackson to the EPA who issued a finding that greenhouse gases constitute a threat to public health and welfare, with a series of actions to reduce carbon pollution. In such a political climate it is unlikely that applications for new mines and plants will receive an accelerated resolution. (Just consider the case of decision on the Keystone Pipeline, which continues to drag on.) If there is a sudden discovered need for new coal and nuclear power plants they will not (as with the Highlanders) be there to answer that call, and nor can they be for over a decade after the call is made.

Now it is not my intention here to argue the logic of a current change to natural gas, as the large reserve within the United States becomes available and, at low cost, provides a source of energy that helps keep the nation’s industry competitive. But what I would like to do is to invoke the same Precautionary Principle that has been used as an initial basis for action on control of power plant emissions and other factors with environmental impact. (see for example principle fifteen).

The precautionary principle can be briefly stated as:
the theory that an action should be taken when a problem or threat occurs, not after harm has bee inflicted; an approach to decision-making in risk management which justifies preventive measures or policies despite scientific uncertainty about whether whether detrimental effects will occur.
There is a significant scientific question as to the long-term reliability of the production levels for oil and natural gas that is being produced from the shales of the United States, and it has been articulated well both by Art and Rune, among others at the Oil Drum.

And as China draws an increasing amount of fuel out of Turkmenistan, Iran and the Middle East, with the potential for an additional increase in the draw from Russia, there is some concern that as China buys for the long-term, that tightening supplies will begin to limit the availability of fuel for Western Europe and the United States.

With the occasional collapse of the odd wind turbine, and the difficulty in seeing how solar power can help in the blizzards and snow storms I have gone through in the last week, there is some concern over the size of the contribution that these technologies can make into the energy mix of the next decade.

In those circumstances, a wise application of the Precautionary Principle to future energy supplies, in both Europe and the United States, might suggest that sufficient legacy power systems be left in place to ensure that neither community is left short of energy in the years ahead. This is to guard against the proposed replacements being either inadequate or insufficient to meet the future need.

And yet, unfortunately this is not likely to occur. As with many arguments and tools used in political debate, once a position or an argument has been adopted it is extremely rare for it to be renounced. The consequences of current decision making rarely come back to haunt those politicians who make them, since they often occur past the current elective term and are thus of less interest to those who are more focused on the next election.

Yet longer-term events do eventually arrive, and time having passed, the day of reckoning is becoming visible. It is likely that the Bakken will peak before the end of the current Administration. Ofgem has already raised concerns over an over-reliance on imported natural gas into the UK, and warned of possible shortages by the end of 2015, and urged a diversification of supply types. The IEA recently issued a chart that shows their projections for the energy future to 2035.

Figure 1. Past and future distribution of energy demand for the different sectors of the world (IEA )

The writing is beginning to appear on the wall. And while the Precautionary Principle is aimed more at less obvious, high risk scenarios – the risks to the world of a failure in the global supply chain, or even a national one is of such a high impact that even with a lower probability of occurrence than is becoming evident, it would be wise to start looking for answers. It is likely already far too late, and the world remains replete with folk denying the existence of a problem (even as gas prices continue to rise) but it will be interesting to see how the new Secretary of Energy addresses the situation.

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Tuesday, February 19, 2013

Waterjetting 6b - The Triangle comparison test

This post is being written in Missouri, and while the old saying about “I’m from Missouri, you’re going to have to show me,” has a different origin than most folk recognize*, it is a saying that has served well over the years. We did some work once for the Navy, who were concerned that shooting high-pressure waterjets at pieces of explosive might set them off, as we worked to remove the explosive from the casing. We ran tests under a wide range of conditions, and said, in effect, “see it didn’t go off – it’s bound to be safe!” “No,” they replied, “ we need to know what pressure causes it go off at, and then we can calculate the safety factor.” And so we built different devices that fired waterjets at pressure of up to 10 million psi, and at that pressure (and usually a fair bit below it) all the different explosives reacted. And it turned out that one of the pressures that had been tested earlier was not that far below the sensitivity pressure of one of the explosives.

That is, perhaps a little clumsily, a lead in to explain why just getting simple answers, such as “yes I can clean this,” or “yes I can cut that” doesn’t often give the best answer. One can throw a piece of steel, for example, on a cutting table, and cut out a desired shape at a variety of pressures, abrasive feed rates (AFR) and cutting speeds. If the first attempt worked then this might well be the set of cutting conditions that become part of the lore of the shop. After a while it becomes “but we’ve always done it that way,” and the fact that it could be done a lot faster, with a cleaner cut, less abrasive use and at a lower cost is something that rarely gets revisited.

So how does one go about a simple set of tests to find those answers? For many years we worked on cutting steel. Our tests were therefore designed around cutting steel samples, because that gave us the most relevant information, but if your business mainly cuts aluminum, or titanium or some other material then the test design can be modified for that reason.

The test that we use is called a “triangle” test because that is what we use. And because we did a lot of them we bought several strips of 0.25-inch thick, 4-inch wide, ASTM A108 steel so that we would have a consistent target. (Both quarter and three-eighths thick pieces have been used, depending on what was available). The dimensions aren’t that important, though the basic shape that we then cut the strips into has some advantage, as I’ll explain. (It later turned out that we could have used samples only 3-inches wide, but customs die hard, and with higher pressures the original size continues to work).

>br>Figure 1. Basic Triangle Shape

The choice to make the sample 6-inches long is also somewhat arbitrary. We preferred to make a cutting run of about 3 minutes, so that the system was relatively stable, and we had a good distance over which to make measurements, but if you have some scrap pieces that can give several triangular samples of roughly the same shape, then use those.

The sample is then placed in a holder, clamped to a strut in the cutting table, and set so that the 6-inch length is uppermost, and the triangle is pointing downwards.

Figure 2. The holder for the sample triangle.

The nozzle is placed so that it will cut, from the sharp end of the triangle, along the center of the 0.25-inch thickness towards the 4-inch end of the piece. The piece is set with the top of the sample at the level of the water in the cutting table. The piece is then cut – at the pressure, AFR, and at a speed of 1.25 inches per minute, with the cut stopped before it reaches the far end of the piece, though the test should run for at least a minute after the jet has stopped cutting all the way through the sample.

The piece is then removed from the cutting table, and, for a simple comparison the point at which the jet stopped cutting all the way through the triangle is noted.

Figure 3. Showing the point at which the jet stopped cutting through various samples, as a function of the age of the nozzle – all other cutting conditions were the same. (A softer nozzle material was being tested, which is why the lifetime was so short). The view of the samples is from the underside (A in Fig 1.)

An abrasive jet cuts into material in a couple of different ways - the initial smooth section where the primary contact occurs between the jet and the piece, and the rougher lower section where the particles have hit and bounced once on the target, and now widen and roughen the cut. Since some work requires the quality of the first depth, we take the steel samples, and mill one side of the sample, along the lower edge of the cut until the mill reaches the depth of the cut, and then we cut off that flap of material, so that the cut can be exposed. Note that the depth is measured to the top of the section where the depth varies.

Figure 4. Typical example of a steel triangle that has been cut and then sectioned to show the quality of the cut.

I mentioned, in an earlier article, that we had compared different designs from competing manufacturers. Under exactly the same pressure, water flow and abrasive feed rates, the difference between the cutting results differed more greatly than had been expected.

Figure 5. Sectioned views of six samples cut by different nozzle designs, but at the same pressure, water flow, AFR and cutting speed.

There was sufficient difference that we went and bought second, and third copies of different nozzles and tested them to make sure that the results were valid, and they were confirmed with those additional tests. Over the years as other manufacturers produced new designs, these were tested and added into the table – this was the result after the initial number had doubled. (The blue are results from the first nozzle series tests shown above).

Figure 6. Comparative depths of cut using the same pressure and AFR but twelve different commercially available nozzle designs.

There were a number of reasons for the different results, and I will explain some of those reasons as this series continues, but I will close with a simple example from one of the early comparisons that we made. We ran what is known as a factorial test. In other words the pressure was set at one of three levels, and the AFR was set at one of three levels. If each test ran at one of the combination of pressures and AFR values, and each combination was run once then the nine results can be shown in a table.

Figure 7. Depths of cut resulting from cutting at jet pressures of 30,000 to 50,000 psi and AFR of 0.6, 1.0 and 1.5 lb/min.

The results show that there is no benefit from increasing the AFR above 1 lb/minute (and later testing showed that the best AFR for that particular combination of abrasive type, and water orifice and nozzle diameters was 0.8 lb/minute).

Now most of my cutting audience will already know that value, and may well be using it, but remember that these tests were carried out over fifteen years ago, and at that time the ability to save 20% or more of the abrasive cost with no loss in cutting ability was a significant result. Bear also in mind, that it only took 9 tests (cutting time of around 30 minutes) to find that out.


* The reason that the “I’m from Missouri, you’ll have to show me,” story got started was that a number of miners migrated to Colorado from Missouri. When they reached the Rockies they found that, though the ways of mining were the same, the words that were used were different. (Each mining district has its own slang). Thus they asked to be shown what the Colorado miners meant, before they could understand what the words related to.

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Thursday, February 14, 2013

OGPSS - Ukraine moves to escape Gazprom's grip

You know it is winter when Russia and Ukraine publically row about supplies of natural gas. On Tuesday Ukraine completed the signing of an agreement with Turkmenistan for the supply of natural gas. In the past the purchases have been for up to 36 billion cu m per year, although this was historically through Russian intermediaries. That deal ended in 2006, and Turkmenistan has been able to find a customer in China that now provides an alternate sale that does not leave it dependent on whatever price Russia was willing to provide.

But this does not mean that Ukraine has been able to escape having to pay whatever price Russia wished to impose, since to get from Turkmenistan to Ukraine the natural gas still requires passage through a pipeline that runs through Kazakhstan and Russia. There is no prize for guessing that Gazprom owns those pipelines.

Figure 1. The Central Asia Center pipeline and the route of the projected Pre-Caspian pipeline – both owned by Gazprom. (Gazprom).

This continues to give Gazprom leverage over Ukraine, and with the North Stream pipeline now approaching its full potential after the second string was commissioned last October, Europe can receive up to 55 billion cu m per year without the gas having to pass through Ukraine.

Figure 2. Path of the North Stream (NordStream) pipeline from Russia to Germany (Gazprom)

There is now talk of adding additional capacity so that there can be a direct feed from Russia to the UK. BP is taking the lead on this, apparently with Gazprom support, although previous experience would suggest that Gazprom may end up as the major shareholder in the end, after all the bills have been paid. And speaking of which, their current dispute with Ukraine involves payment for $7 billion worth of natural gas,that Ukraine contracted for but did not, in the end use during 2012. Ukraine is paying $430 per thousand cubic meters ($12.18 per thousand cu ft) for a fixed volume per year, whether they use it or not, under an agreement signed in 2009.

There is some implication that this pressure may be related to the recent 50-year production sharing agreement that Ukraine signed with Shell to develop natural gas from shale deposits. The country is believed to have the third largest shale-bound natural gas resource in Europe (behind France and Norway ) estimated at around 42 trillion cu ft (1.2 trillion cu m).

The deposits are centered around the Yuzivskaya region, with production anticipated to start in 2017, rising to levels of around 8 – 10 bcm in ten years. Although there is some domestic opposition to the development, the schedule is aggressive.
Shell is to work with Nadra Yuzivska, a joint venture in which the state-owned resources company Nadra Ukrayiny owns 90%. SPK-Geoservice, a small private company, owns the remaining 10% in Nadra Yuzivska.

Shell is expected to invest $410 million to drill the first 15 wells, Oleh Proskuriakov, the environment and natural resources minister, said earlier in January.

The total area of the Yuzivska field is 7,886 sq km. The deposit could hold 4.05 Tcm of gas, according to the government. Proskuriakov has also projected output from Yuzivska could hit 10 Bcm/year in 10 years and 20 Bcm/year in 15. Ukraine's Stavytskiy characterized the latter figure as representing the "optimistic scenario."

"We can project that in an optimistic scenario, the project will produce 20 Bcm/year of gas, while under a pessimistic scenario, 7-8 Bcm/year," Stavytskiy said.
An adjacent well drilled by Hutton has shown promising signs of “interpreted pay in three intervals.”

Chevron is expected to develop deposits in the Olesska region with start dates of around the same time. Opposition to their plans seems to be growing, and they have yet to sign a production sharing agreement. They are, however hoping to get the same sort of deal that Shell negotiated.

It is worth injecting a note of caution into this optimistic view of the future. Just a year ago Poland was anticipating a similar bonanza from the natural gas in its shale deposits. Events have limited that dream. Although a 2011 EIA report stated that Poland had 187 tcf of technically recoverable natural gas, the Polish Geological Institute has now cut the estimates of the viable size of the resource by 90%, and there are other problems.
Difficult geology, an uncompetitive service sector, poor infrastructure, and lack of rigs have hampered development. Poland has a venerable oil and gas sector, but most of the transmission pipelines are based in the southwest, while major shale gas areas are in the northeast. Strict EU environmental laws, as well as unclear regulatory and tax frameworks have further eroded prospects. And while exploration has been going on for a few years now, only 33 wells have been drilled, with just eight of them fracked (at least 200 would have to be drilled in the exploratory stage, just to assess the actual size of reserves).

Preliminary results have not been encouraging, either: This summer, resource giant ExxonMobil withdrew from Poland after the failure of commercial gas flows, while its competitor ConocoPhillips decided not to exercise its 70 percent option in three concessions in northern Poland. Overall, costs per well have increased to $15 million, according to interviews with industry officials, roughly three times the cost in the United States.
And there are two more factors that should be considered. Ukraine is planning an LNG plant on the Black Sea to be ready by 2015, but even this is controversial. To reach the Black Sea tankers will have to pass through the Bosphorus and Dardanelles straits, and Turkey has intimated that it may not allow LNG tankers rights to that passage. That is because the terminal would compete with two that already exist in Turkey.

Secondly Ukraine is working with the Chinese to gasify some of their coal from their large deposits, with the intent of producing the equivalent of 4 bcm of natural gas to displace Russian imports.
The projects are two-fold: first, heat-producing facilities will be converted to use coal-water slurry as fuel; second, new plants will be built to enable the gasification of brown and bituminous coal in three regions: Luhansk, Donetsk and Odessa. While most of the media reports claim that Ukraine will be using Chinese coal-slurry technology, it’s actually Shell’s technology.
How soon Ukraine (and Poland) can stop imports of energetic fuels from Russia is not clear, but obviously this should happen before long, and the winters of their discontent may well disappear from the headlines.

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Wednesday, February 13, 2013

Waterjetting 6a - An introduction to testing nozzle performance

In the next few posts I will be writing about some of the tests that you can run to see how a nozzle is performing. But before getting into the details of the different tests, you should recognize that this is where a little homework will be required if you are to get the most benefit from the topic.

The world that encompasses waterjet use has grown beyond the simple categories by which we used to define it. New techniques make it possible to cut materials that used to be more difficult and expensive to produce, and as practical operational pressures have increased so the scale, precision and economics of new opportunities have developed.

It is this range of application that makes it impractical for me to give specific advice for every situation, and instead, by explaining how to make comparisons, and what some benchmarks might be, to allow you to better understand your system, its capabilities and both the initial performance of nozzles, and then the evaluation to decide when they may best be replaced.

One lesson I learned early was that nozzles from different companies behaved in different ways, and that drawing conclusions on optimal performance, for example the selection for which pressure level and nozzle size was best, using one design would not necessarily hold with a competing design. Further there were nozzles that began their life on our system doing very well relative to others, but which quickly declined in performance. Thus, as part of an evaluation of different designs, we would test the nozzle cutting performance, against a standard requirement, at fixed time intervals so that we would know when it was wearing out and should be replaced.

Figure 1. Change in the cutting depth of a jet stream, at 50,000 psi, when traversed over ASTM A108 steel as a function of the time that the nozzle had been in use.

Both the shape of the curve and the effective lifetimes of different competing nozzle designs varied quite significantly. And obviously, since most folk don’t spend a lot of their time cutting through more than an inch of steel, the operational lifetimes of nozzles will vary with the requirements for the particular job. Nevertheless the relative ages at which nozzles can no longer reach that target can differ significantly,

Figure 2. Comparative effective nozzle life over which, operated at a pressure of 50,000 psi, a jet could cleanly cut a path through a 1.4 inch thick steel target at a traverse rate of 1.5 inches/minute.

As mentioned, the tests were carried out using nozzles from several manufacturers and, at the beginning of the test the longest lasting nozzle was not necessarily the one that produced the fastest cut, but consistently, over the interval, and for about twice as long as the competition, it was able to achieve the goal.

Figure 3. Depths of cut in steel after (top) 1,000 minutes of nozzle use, and (bottom) after 1,500 minutes of nozzle use.

In the particular case in which we made the comparison the major interest was in achieving a clean separation of the parts, and the edge quality was not as significant a factor. In many uses of this tool that edge quality will be important and would have given a different set of numbers (as Figure 3 would indicate) than the ones that were found for our application. As a result the judgment that the nozzle is worn out will change to a different time, and the relative ranking of the different nozzle designs may also change.

The only way in which anyone can make a rational decision on which is the best nozzle for an application, and how long it will be effective is by testing the nozzle against the stated requirement. When we began the test we anticipated that the difference between nozzles from different manufacturers, when fed with water at the same flow rate, and with the same quantity and quality of abrasive would not differ that much. As Figure 2 shows, we were wrong in that idea.

There are a number of different impacts that a change in nozzle design (i.e. in most cases buying a competing design over that initially used) can bring to a cutting operation. However these impacts are also governed by the pressure at which the work is being carried out, the amount of abrasive that is used, the relative nozzle diameters (if using a conventional abrasive waterjet system) and the speed at which the cut is made. But an initial assessment of relative merit should be carried out with equivalent parameters for the different designs.

In general, however, we ran tests at a number of pressures, and with varying abrasive feed rates, to ensure that the comparative evaluations were fair, and consistent. As a result we found that there were a number of different factors that came into play, which are not always recognized, and which could bias the results that we observed.

In the posts that follow this I will first cover some of the different tests that can be used, and then go on to explain some of the results and why they sometimes make it difficult to accept a simple comparison of results when, for example, the abrasive is not the same in both cases. To give a simple example of this, consider a conventional abrasive waterjet nozzle that is operated at increasing pressure.

Increasing the pressure will improve the cutting speed and/or the cut quality, as a general rule. It will reduce the amount of abrasive that is needed, but this is where the “yes, but’s . . . .” start to appear. As the pressure of the jet increases, so the amount of abrasive that is broken within the mixing chamber will also increase, so that the average size of the particle coming out of the nozzle will become smaller. The amount of this size reduction is a function of the quality of the abrasive that is being used, and a function of the initial size of that abrasive.

Within a certain size range, that reduction in the particle size does not significantly change the cutting performance, but if the mix contains too many small particles, particularly if the distance to the work piece is also significant, then the cutting performance can be reduced because of the particle break-up. Different nozzle designs produce different amounts of very fine material even from the same feed rate of the same abrasive into the nozzle. When the initial feed rate of the abrasive, or a different abrasive is used, then estimating which design and set of operating pressures is best becomes more difficult, as an abstract estimation.

This is why, in the posts that follow, the comparisons are made are based on actual measurements and why I recommend that everyone test their system using more than one design/set of operating parameters so that they can be confident that the combination that they are using will provide the best combination for the job to be done.

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Saturday, February 9, 2013

Snowy Days and old DNA

We left Boston on Friday morning, just as the storm was rolling in, and by the time we got to the New Hampshire border there was snow over the Interstate, and driving was self-restricting to two lanes. Driving got a little tougher that evening (glad to get out of Mass before the governor closed the roads at 4 pm) but we managed, though there was, by the time we made the hotel at night, about a foot of snow on the ground.

Today, Saturday, that had increased to over two feet, which made it difficult to get out and do anything, other than dig the path. Of course, as it was just about finished, along came the snow blower - but this being Maine, they carefully redirected the flow so that it missed the path.

Figure 1. Snowblowing the sidewalk.

And since they left a wall between the sidewalk and the road, it will be safe to walk back to the hotel tonight. But being caught by the snow I started to try and catch up on one or two things.

For example there is the role of DNA in identifying royalty, most recently with the finding of the body of King Richard III. Because of his somewhat rare mitochondrial DNA, investigators were able to locate two family descendants which validated the remains were those of the king. He will be reburied next year, and there will no doubt be a resurrection of his reputation. But since I went to Lancaster, and he was the leader of the White Rose York side of the Wars of the Roses, perhaps I won't be too sympathetic.

On the other hand DNA had an interesting role to play in identifying another monarch, albeit one a little older.
In 1993, archeologists found the mummified body of a young woman on Ukok Plateau in Russia's Altai region. The plateau is located in the area of Russia's border on Mongolia. The mummy of the woman with a tattoo on her shoulder became known as the Princess of Altai. Scientists from Novosibirsk say that the cause of the woman's death, who died 2,500 years ago, is still shrouded a mystery.
I am likely to return to this Princess of the Pazyryk people at some future date, but had thought that the Princess was of similar extraction to the two soldiers who were buried with her, and which were of a more Asian background. However the rendition of her head has a more Aryan structure, and it turns out, through analysis of her DNA, that, to quote Pravda:
The Princess of Ukok does not relate to any of (Asian) races. She has a European appearance, she is 170 centimeters tall. A DNA analysis revealed her haplogroup R1a - Aryan blood. According to experts' estimates, 70 percent of eastern Slavs belong to this haplogroup.

Altai Aborigines say that the mummy is their progenitor. They call her Princess Kadyn, or Kydyn. The tattoo on her arm conceals very important information for mankind. The time to read the information has not come yet, Aborigines say. They also believe that the woman was a priestess and that she passed away voluntarily to protect the Earth from evil spirits.
So, if I am to model her, and her tattoos, it poses several questions . . . . . There is no more, yet!

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Thursday, February 7, 2013

OGPSS - Future Bakken production and hydrofracking

Before there were refrigerators folks kept drinks cool by putting them into clay jars that had been soaked in water. The evaporation of the water from the clay cooled the container and its contents, which today includes wine bottles. On the other hand, for many years artisans have taken clay in a slightly different form, shaped it and baked it and provided the teacups which keep the liquid inside until we drink it.

Two different forms of the same basic geological material, with two different behaviors and uses. Why bring this up? Well there is a growing series of articles which continue to laud the volumes of oil and natural gas that the world can expect from the artificial fracturing of the layers of shale in which these hydrocarbons have been trapped for the past few million years. It has been suggested that there is no difference between this “unconventional” oil and the “conventional” oil that has been produced over the past century to power the global economy. And yet, despite the scientific detail which some of these critics discuss other issues, they seem unable to grasp the relatively simple geologic and temporal facts that make the reserves in such locations as the Marcellus Shale of Pennsylvania and the Bakken of North Dakota both unconventional and temporally transient. Let me therefore try again to explain why, despite the fact that the oil itself may be relatively similar, the recovery and economics of that oil are quite different from those involved in extracting conventional deposits.

But, before getting to that, let’s first look at the current situation in North Dakota, using the information from the Department of Mineral Resources (DMR). According to the January Director’s Cut the rig count in the state has varied from 188 in October, through 186 in November, and 184 in December, to 181 at the time of the report. Why is this number important? Well, as I will explain in more detail later, the decline rate of an individual well in the region is very high, and thus the industry has to continue to drill wells at a rapid rate, just to replace the decline. (This is the “Red Queen” scenario that Rune Likvern has explained so well.) The DMR recognize this by showing the effect of several different scenarios as the number of rigs changes.

For example they project that 170 rigs will be able to drill around 2,000 wells a year. At that level, and with some assumptions about the productivity of individual wells that I am not going to address here, but which Rune discussed. I would, however, suggest that it is irrational to expect that new wells will continue to sustain existing first year levels as the wells move away from formation sweet spots. Yet, accepting their assumptions for now, DMR project that the 170 rigs will generate the following production from the state:

Figure 1. Achieved and projected North Dakota production when 170 rigs are used to continue to develop the field into the foreseeable future. (ND DMR).

The DMR plot also assumes that the wells are developed and brought into production in a timely manner. In October the state produced an average of 749 kbd of oil, which was through mid-January the current peak level of production. Currently it is estimated to cost $2 million to frack a well, and in January there were 410 wells waiting on that service.

In order to reach a higher level of production (and bear in mind that OPEC has been projecting significant further increases in production to make their anticipated supply and demand levels balance) the DMR looked at estimates of production if there were 225-250 rigs, and contrasted that with what would happen if the rig count fell almost immediately to 60.

Figure 2. North Dakota oil production with either 225-250 rigs, or with 60. (ND DMR)

Note that at 60 rigs the state production goes into an immediate decline. Somewhere in between those two extremes lies the likely future, but with the Director noting a December price of $77.09 that future may be at the lower, rather than higher end of the scale. (Though in January it popped back up to $87.25).

To illustrate the sensitivity of these numbers consider that if the rig count fell from 170 to 100, then production would decline to 800 kbd but would still fall into decline in 2020, while at 200 rigs the production would rise to a peak of 1 mbd, although the peak interval might only be four years from the 2,400 new wells added each year.

The ferocity of the decline rates of these wells is part of the reason that they are called unconventional, since they do not behave in the same manner as a conventional well, nor can they be developed in a similar way.

To return to the geology of the deposits (and shale is a consolidated clay) the middle Bakken formation is made up of a combination of layers of shale, sandstone, siltstone and limestone. These are, in general, rocks that have a very low permeability, and that property was explained in more detail in an earlier post. Simplistically it is a measure of how easy it is for fluid to flow through the rock, and for most of the Bakken rock it is not easy at all. If it were then there would be no need to put in the crack paths that the oil uses to reach the well. Let me repeat a figure from that post:

Figure 3. Block of sandstone with a crack in it (shown by the arrows).

I have been on a site where my hosts (a federal agency) had injected fluid that they were hoping would penetrate a layer of ground so that it would form an impermeable barrier. It had not, even though the ground was relatively easy for the fluid to penetrate. Instead it had all flowed into a crack no bigger than the one shown in the picture above, and the attempt was a failure.

Put that into reverse where you are trying to pull fluid out of the ground. There are two places where the fluid (oil or gas) is located, in the natural cracks and joints of the rock – which the hydrofrack is designed to cut across. And in the much lower permeability of the blocks of rock that are edged by these fractures, bedding planes and joints.

Figure 4. Representation of a horizontal well drilled in the Marcellus, shown against the natural fracture pattern (Source AAPG )

Over the millennia the oil/gas has migrated to those bedding planes and natural joints and fractures in the rock. When the well is first put in place it is that fluid that is more easily available to flow through the intersecting crack pattern to the well. But as those interstices empty out it is much more difficult to move the oil from the rock surrounding the natural cracks into that crack and thence to the well.

Most illustrations of hydraulic fracturing show a network of artificially induced cracks getting more numerous as they move away from the well. That, actually, is not the way it normally happens. The majority of the cracks that open are already there, and these are much easier to develop – as my unfortunate hosts learned – that it is to try and generate a multiplicity of new fractures, as I have previously explained here and here. The production, to go back to my initial metaphor, begins to move, over that first year of production, and dramatic fall in yield, from relying on the permeability of the wine cooler part of the rock, to that of the teacup.

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Monday, February 4, 2013

Waterjetting 5d - Fitting the nozzle to the system

Buying a high-pressure system requires a significant amount of money, and, as a result, most folk will make a serious attempt at comparing the quality of the different systems that they are considering buying, before they make that choice. Most of the expense goes into that part of the system that sits behind the nozzle, and which supplies the water and (where needed) the abrasive that form the cutting/cleaning system.

Often, however, while the upstream system is the subject of such scrutiny, the nozzles themselves, and the selection of abrasive often escape this level of evaluation. Both of these “parts” of the system are part of the wear cost of operations, and, as a result, the selection of the “best’ nozzle often involves operational cost considerations, with less emphasis on comparative evaluations of performance. To explain this most brutally, a company may spend $250,000 on a system, but then degrade the performance of that system by over 50% by choosing a nozzle system that saves the company 15% on purchase costs over that of a competitor. (I will show figures in a later post on this topic).

In the next few posts I am going to explain some of the tests that we, and others, have run to compare nozzle performance, and some of the results that we found. I don’t intend to “name names” because the tests that I will talk about are specific to certain specific objectives, and the reason that you are running a system will likely differ from the conditions and the performance parameters that we needed to match for some specific jobs. The evaluations will range over a number of different applications and will cover some quite expensive tests, as well as some very simple ones that can be run at little cost in time or money.

But, to begin, the first question relates to how you attach the nozzle to the end of the supply pipe. Here you are, if you have followed the train of thought of the last two posts on conditioning the water as it leaves the supply pipe, through a long lead section, or through a set of flow conditioning tubes, the water is nicely collimated and (as I will show) could under certain circumstances have a throw distance of perhaps 2,000 jet diameters or so. Yet the average jet has an effective distance of around 125 jet diameters. Why the difference? An illustrative sketch from Bruce Selberg and Clark Barker*, simply makes the point.

Figure 1. Comparison between a typical nozzle attachment and one where the flow channel is smoothed. (Barker and Selberg)

Right up to the point where the small focusing nozzle is attached to the pipe on the left (a) the flow has been conditioned to give a good jet. But then, just as the flow starts to enter into the acceleration cone in the nozzle it hits the little step at the lip of the nozzle where it attaches to the pipe.

As I will mention in a later post, when a jet hits a flat surface and can’t penetrate then it will flow out laterally along that surface. (This also happens with wind, and is why places such as Chicago are referred to as "The Windy City.") So the outer layer of the jet hits the lip, and where does it go? It runs right into the path of the central flowing jet into the nozzle and mixes right across it. So much for stable flow, that lateral disturbance turns the flow turbulent, so that it is rapidly dissipated once it gets out of the nozzle. Professors Selberg and Barker calculated the theoretical pressure of the jet coming out of the orifices, and compared it with pressure values that they measured.

Figure 2. Measured pressure profiles plotted against the theoretical pressure (small crosses) at different distances from a typical conventional nozzle with two orifices.

In comparison, as a way of ensuring that the flow path into the two orifices was smooth, the two authors added a small section made of brass between the end of the pipe and the entrance to the nozzle body ((b) in Figure 1). They inserted two pins to fit into alignment holes drilled into the end of the pipe, in the insert, and in the nozzle body itself.

Figure 3. Construction of a feed section between the nozzle body and the feed pipe to stabilize the flow (Barker and Selberg)

When the pressure profiles were taken with one of the new set of nozzles, the difference, as a function of distance, was quite marked.

Figure 4. Profiles from the nozzle design shown in (b) with a two-part nozzle (Barker and Selberg. Note that the standoff distance has increased for the two sets of profiles over that in Figure 2.

Further, when the depth of cut was measured after the jets were fired into blocks of Berea Sandstone at various distances from the nozzle, the improved performance was clear out to even further distances.

Figure 5. Depths of cut into blocks of Berea sandstone as a function of distance from the nozzle, at two flow conditions (Barker and Selberg)

The addition of the flow channeling section does make the nozzle a little longer, and the cone angle of the inside of the nozzle was continued out to the diameter of the feed pipe to reduce any steps that might induce turbulence. In addition the inside of both the transition section and the nozzle were polished to a surface finish of better than 6-microinches.

The nozzles themselves were specially constructed for us using electro-formed nickel on flame-polished mandrels and were thus quite expensive. Our particular purpose, however, was in the development of a mining machine that, with the nozzles that we used, was able to peel off a slab of coal, to the height of the seam, and to a depth of 3 ft, at a rate of advance of at least 10 ft/minute. (A later design in Germany went over 6 times as fast, when operated underground).

The advance rate was achievable because the jets were cutting a slot consistently about 2 ft ahead of the machine, and with two jets the coal between them was washed out without having to be mined. But that is a subject for a different post a t some time in the future.

Before I leave the subject, however, some folk might comment that their nozzles sit in holders that are then threaded onto the end of the pipe – thus they should be in alignment, and they are tightened until the holder is tight on the pipe. There are two caveats with this, the first is that this does not necessarily mean that the entry into the nozzle smoothly butts up against the end of the pipe, and in alignment with it. (Hence our use of pins.) In field visits we have measured, for other operators, the relative distances involved, and found that there can be a gap between the end of the nozzle body, and the end of the pipe, both contained within the holder. Even though the two diameters are the same, the presence of the larger chamber before the entry into the nozzle will again create turbulence and a poor jet.

The fix in both cases is a small transition piece, which is simple to design and insert to fill that gap, and smooth the passage. Though it does bring with it the second caveat. You need to make sure that the number of threads of engagement of the holder on the pipe remain enough so that the holder won’t blow off if the nozzle blocks. (One time one of ours did, but it was in a remote location, so thankfully no-one was hurt, although there was some damage as a result).

In the next post I will start to discuss the different ways that we have used, after the nozzle is in place, to make sure that the jets were doing what they were designed to and producing a jet of the quality needed.

* The information that I used in this article can be found, in more detail, in the paper: Barker, C.R. and Selberg, B.P., "Water Jet Nozzle Performance Tests", paper A1, 4th International Symposium on Jet Cutting Technology, Canterbury, UK, April, 1978.

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