Temperatures in the Mountains - the Colorado data

Today I am going to look at the temperature data for Colorado, since last week we looked at the data from Kansas, and the correlation with longitude was growing, but could not just be explained by a change in height. The procedure starts off the same as that for the initial post, in that I am going to take data from the US Historical Climatology Network compare it with the GISS data for Colorado, (which I reference later) and then see if I can draw some conclusions from the data. I want to have a hypothesis to test against the data, and since the land rises in the West, and it gets cooler, the hypothesis this week is that there is a relationship that we can derive between average temperature and height above sea level. There is a subsidiary corollary to this, which is that this will explain the changes in temperature with longitude.

So to begin we find the data for the weather stations for Colorado. There are 24 of these, and so I begin by generating the table that I described in the first post of this series. This lists the site with its geographic location and leaves a space for the population. Under that I put the average annual temperature data for that site from 1895 to 2008. (and since I am writing this as I do it, there will now be a pause . . . .)

And there is a slight problem – in 1896 there is no temperature data for Telluride. Hmm! How to handle this? Well looking at the averages that for 1896 is on average 0.6 deg above that for the stations in the rest of the state. Telluride, on average is 9.54 degrees below the average for the state. So if I take the average for the state for 1896 and subtract 9.54 I get 37.1 degrees. If I take the average for Telluride and add 0.6 degrees I get 37.17 degrees. So it seems fair to insert a temperature of 37.135 degrees for Telluride for 1896 – which I did to complete the initial table.

Now to get the data from GISS, and here there is another surprise – I have checked the list that Chiefio gives 3 times and still can only find Grand Junction as a site in Colorado, even though the GISS site lists some 33 sites with data, of which a fair number also appear on the USHCN list. So I will just use this as the sole GISS site for Colorado. Getting the data from GISS and correcting it for scale (from Centigrade to Fahrenheit), then I run the table, and the next surprise of the evening. The GISS site is, on average over the 114 year period 6.65 degrees warmer than the state average. Plotting the average difference over that time interval


Now there is only one GISS station, but this is rather a large amount warmer for the state according to GISS than the state average would suggest. It has, however, been declining slightly, but steadily over the years. As for the state temperature as a whole, that has been increasing, though the pattern is a bit strange.


So now I go to enter the population, and not being a Colorado native I had been wondering where the Denver data was, and apparently it is hiding behind the Cheesman file. (That being a suburb of Denver apparently with a Park). So do I use the suburb population 8,201 or that of Denver itself – 598,707? Given that the area has a high population density, I am going to use the Denver number.

And then there is the problem of finding Hermit, CO – fortunately the weather station information includes the co-ordinates (since I didn’t have a great deal of success with a Google search) and this allows me to use Google Earth to go to the co-ordinates and find that it is at Hermit Lakes, which is in Creede, population 377. Putting all those together, there really are a lot of small communities in Colorado, so I’ll use a normal (rather than a log) plot of the information.


And with this having a lot of data at the smaller end of the scale (and recognizing that we have yet to go to a state with large populations) there is some correlation to a log relationship. And changes in small populations could have a greater significant effect. (Which is what I had said earlier, and which is now being also being written about by Professor Roy Spencer.

Interesting where there weren’t any large mountains (i.e. Missouri) there was a good correlation with latitude, but in Colorado that is not as evident:


And instead, where further East there was no correlation with longitude, in Colorado it is very pronounced:


So the question is, can this all be explained by the changes due to height above sea level, or elevation?


I don’t think that there can be any doubt of the correlation. So now we have two – where there is not a large change in elevation (Missouri) there is a strong correlation with latitude, but when the stations are at a higher altitude, then there is a strong correlation with elevation. And the starting hypothesis, this time, is seen to be correct.

One wonders how it would be if we normalized the data to account for both elevation and latitude. Given the lateness of the hour I won’t do that tonight, but given that GISS gives the locations for the centers of the states, maybe I will adjust the data to that location based on the linear relationships and see what that produces, and how much variation it takes out. But I’ll do that later in the week (we have been beset by server problems today, and I would like to get this out before I get hit with another).

As demand rises, can oil supply keep up?

Liquid hydrocarbons provide the fuel for the vast majority of the vehicles that carry us to and fro over the course of a day. The latest edition on the TWIP comments, in looking at the future of vehicles through the eyes of the Annual Energy Outlook, released this month, that:

the market share of alternative vehicles will increase to 49 percent of new vehicle sales by 2035 due to the combination of more stringent corporate average fuel economy standards, the renewable fuel standard and higher fuel prices (See Figure 1). However, with continuing improvements in the fuel economy over time, conventional gasoline-powered vehicles are projected to retain the majority of sales.

Figure 1 looks like this:

EIA projects for vehicle fleet changes in future years (EIA)

But the projection carries with it some inherent assumptions about the continued availability of those fuels, both here and in the other countries around the world. And in some of those growth is expected to be such that, by 2035, countries such as China will have more vehicles on the road that the USA. Last year the Chinese car industry overtook that of the United States, and just recently Saudi Arabia began selling more oil to China than it does to the United States. Sales to the US averaged about 2,000 bd below 1 mbd last year, while those to China just crossed that significant marker. Similarly Russia, the country that now leads the world in crude production, increased its sales to China so that it now supplies around 7.8% of total Chinese crude imports. (Through last October this amounted to around 100 million barrels of oil for the year).

There is a new pipeline that is being constructed to help those exports, with the goal of increasing sales from their current 6% of Russian exports to between 20 and 25%.

After many years of discussions, the construction of the pipeline started in April 2006. The ESPO was supposed to connect Tayshet (in the Irkutsk oblast) with the Kozmino port on the Pacific Ocean. The new oil pipeline is intended to stimulate the development of a new oil production centre in Eastern Siberia, which is particularly important in view of the expected decline in production from the Western Siberian fields and in the Urals-Volga region. The ESPO's total length will be 4857 km and it will have an annual capacity of 80 million tons. The first section between Tayshet and Skovorodino (Amur oblast) has a capacity of 30 million tons.

Initially, oil will be transported from Skovorodino to Kozmino by rail. The second phase of the project (to 2014–2015) will see the construction of the pipeline section to the terminal in Kozmino (50 million tons) and the expansion of the first section’s capacity to 80 million tons. Moreover, a branch connecting the ESPO with China's Daqing has been under construction since April 2009; it is expected to start transporting 15 million tons a year in 2011 (with an option of extending the capacity to 30 million tons).

Russia’s Energy Strategy through 2030 does not see a shift from fossil fuels to alternative energy until after 2022.

Now these projections of growth, and the fuel supplies required to meet them are predicated on there being enough, relatively economically viable, supplies of crude to meet that demand. There are the occasional troubling signs that this might not be the case.

JoulesBurn has one of his usual, incisive and informative posts on The Oil Drum today discussing his latest analysis of information from the satellite view of the recent Saudi addition at Haradh. This, the third addition to the program of extraction from the Southern tip of the large Ghawar field, is being produced, and bragged about by the Saudi, at a level of 300,000 bd. But as Joules has spotted, and pointed out, there are a lot more production wells that have been drilled into that field in recent years than Saudi Aramco have been admitting to, and their placement suggests that they are being needed to maintain production from wells that might not have been able to sustain the original targets.

Now that could be a problem, and Ace has commented that this could signify that Aramco might not be able to sustain more than 8.35 mbd this year, and expects a decline next year.

Into this picture now increasingly steps the slowly growing global economy. And as it seasonally happens US demand for gasoline is beginning the steady increase that normally occurs between now and mid-summer, with the concomitant increases in price.

US Demand curve from TWIP (March 3, 2010 )

Turning to the vehicle miles travelled data for last November the numbers were positive across the entire country, with an average increase of 1.4% over the previous November. (This is in contrast with the October figures where the overall had shown a drop of 0.7%, the first drop in 5 months). The rolling 12-month total, because of that, reached a plateau, though I expect that it will return to upward progress next month, perhaps beginning to exceed the driving done in 2004.

Rolling 12-month total of vehicle miles driven in the USA through November 2009. (FHWA )

The endurance of University data records - be discouraged

Much has been made of the destruction or loss of data from the files of the Climate Research Unit (CRU) of the University of East Anglia. Dr Phil Jones, The Director until this all became public, did not do himself much benefit with his remarks before the Commons Select Committee in the UK, that is looking into the Climategate matter. Destroying the raw data, or not making it available, so that all that one can use is the modified and gridded data, means that there are no checks that the adjusted data has been properly derived. But the destruction of research data is not only encouraged in some institutions, it is mandated by regulation. It is, however, a point that a lot of folk may have missed. So I thought I would mention this since I suspect that it affects much more than just the data at my own University.

I retired from the University last Friday, and have spent today throwing away about 80% of the material in one of the three offices that, transiently, it has been stored in. (It happened that in recent months the three folk who had worked with me on many of my research programs also retired, and so their records were boxed and collectively stored with mine until they could be sorted). We worked through file after file, with data going back to the first experiments that I had run some 40-years ago when I came to this place as a very junior Assistant Professor. That data was still on graph paper, with hand-plotted curves. It went into the trash barrels. As did many of the journals that I had paid large chunks of money for over the years, and almost all of the correspondence dealing with the millions of dollars of contracts that I have managed during my term here.


I am working with the University Archivists, and they and a couple of students helped me work through many of the files, and did most of the actual disposal. We have done some pretty interesting things over the years (I was incredibly fortunate to be involved in many of the activities that changed my discipline from an academic curiosity into something that impacts, in one way or another, many peoples lives every day). But not much of that is being kept.

A treatment for skin cancer that discriminates between healthy and diseased tissue – save the patent – the rest into the trash. Cleaning the Statue of Freedom atop the Capitol building in Washington, save the proposal, the final report and one paper. The rest – into the trash.

You might think that I am being deliberately destructive, but this is what the regulations require. For those as incredulous as I was, until last week, here is the information:



Notice that the applicable dates are for three years back. In other words three years after I get a contract or grant I am supposed to archive the proposal, report and the sample of data (the paper that I mentioned earlier), and then four years later I am supposed to destroy all the research data. Hope the sanctions are not too onerous, since, until today I had kept everything. Now much of it lies in grey trash bags stacked down a hallway.

I actually got a bit annoyed about this last week, and it was then that this all came to my attention. As it happened when my pension was calculated (ours is based on length of service) the record did not show that I worked for part of 1997. Now I knew that I had, but if I (or actually the Center staff) had followed University rules, rather than what I had wanted, then there would have been no other record against which to compare the facts relative to the records that are in the Central Personnel Office. Given, however, that we had kept the records, the copy was found, sent up and the matter was straightened out within about an hour. (However, since a large number of boxes have recently left for the incinerator I don’t believe that my replacement as Director has continued my cautionary practice).

In the past the Center has been audited, and had, on another occasion to defend a set of experiments that were investigated by a government agency. In the first case I found a record from a period that I suppose I should have had destroyed that showed that the audit inquiry was misinformed, and in the other I was able to supply all the documentation required (foregoing that it took several full weeks of several individuals time to copy – this being before much of our information was stored digitally). As a result, and based on that information, the inquiry was discontinued.

The amount of space that is needed to store digital records is trivial against the bookcases of material that have just gone into the trash. But storing the material only in digital form has some risks. I have just finished a comprehensive review of one of our programs, requiring data that was stored digitally back in about 1987. I cannot open the files for any of the information. I can’t find readers that will read some of the disc storage that I recorded it on. (And where I made copies of the files and transferred them, the current versions of the software won’t read files from that far back). It wasn’t in this case too much of a problem since, in violation of policy, I had the paper copies and just scanned them in to get what I needed (and created a digital copy), but those paper copies will be in those grey bags next week.

There are problems with data storage. If I had kept the written records, then when I vacate the room, then the books will go onto a bookcase in the hall for the students who want them to help themselves (my colleagues already have), a small amount of material will go home, some will go to the Archives, but the majority will burn, or be landfilled. Because the person who follows me into that space has their own research and documentation, which they will put into the bookcases that I am vacating. There is not enough room to store the material. We used to use microfiche to do that – I haven’t seen anyone use one of those readers in years, I stopped when ours broke.

The Federal Government and the National Labs are no different. I was on a National Panel which needed some information on a project from one of the National Labs and we wrote for it. It was about 15-years after the experiments. They no longer held the data, and there was no-one there that we could talk to about the work. (Which was one of those supposedly crazy ideas that folk go out and try, and bless my socks, this one worked, and might have been helpful if we could have found out more).

So while I continue to think that it is madness to be spending the amount that we are on research into the possible problems of the greenhouse gases without a more robust set of raw data that everyone agrees has integrity and that has been compiled in a way that is logical and transparent, I have to point out that the protocols governing records at Universities are not supportive of my position. Not that this makes me feel any better, rather the reverse. And there are many, many research programs that do not have that level of visibility.

I used to joke in my class that disasters happen in about 20-year cycles, because nobody read anything that was older than that, and thus missed some less-than obvious design features, which became forgotten until their lack led to disaster. But I had not realized that the data was all gone. And in the digital age, if it isn't on the web who knows where to look for it.

Troubling thoughts!

Test results from nuclear stimulation of oil and gas reservoirs

Hmmm! Well the tone of some the comments on my last post -dealing with nuclear development of oil shale,, both recently and when I initially posted it on TOD helps illustrate one of the points that I want to make in this, a continuation in the posts on oil shale. The tone was quite negative, in general, with a number of folk being disturbed at my even bringing it up. It points to the fact that, as a political reality (bearing in mind that I try to stick to technical matters in this series) the use of nuclear adjustment to the local geology is not likely going to be popular. As tstreet noted after the original post, there is an article in the Colorado Constitution (article XXVI) that he helped put in there.

Section 1. Nuclear detonations prohibited exceptions. No nuclear explosive device may be detonated or placed in the ground for the purpose of detonation in this state except in accordance with this article. (Adopted by the People, November 5, 1974. Effective upon proclamation of the Governor, December 20, 1974.)

Section 2. Election required. Before the emplacement of any nuclear explosive device in the ground in this state, the detonation of that device shall first have been approved by the voters through enactment of an initiated or referred measure authorizing that detonation, such measure having been ordered, proposed, submitted to the voters, and approved as provided in section 1 of article V of this constitution. (Adopted by the People, November 5, 1974 Effective upon proclamation of the Governor, December 20, 1974.)

While I did not know about that as I initially planned this series, I had intended just to point out that the unhappiness of just one Senator with a nuclear program (and I was thinking of Senator Reid and Yucca Mountain) can delay and ultimately kill its implementation. In this case it is likely that there would be at least eight senators opposing, and I think the point is made. However, since I do think it is useful for folk to know these things, I thought I would continue with the rest of the story from a technical point of view. Particularly since the use of nuclear energy for excavation has recently been revisited by WIRED magazine.


Following the debates about the potential benefits that might occur from the use of nuclear explosives it was decided to see if it would work in three test detonations, that were given the names Gasbuggy ; Rulison and Rio Blanco.

The Gasbuggy shot, in 1967 used a 29 KT device at a depth of a 4,240 ft deep shaft, and created a cavity that was 80 ft wide and 335 ft tall, when one included the chimney. It also fractured the light shale around the opening. Anticipated dimensions were 165 ft with a 350 ft chimney.

The Rulison shot, in 1969, used a 43 KT device at a depth of 8,426 ft. it produced a cavity that was 152 ft wide, with a fracture zone that extends some 200 ft into the surrounding sandstone. (Predicted size was 160 ft with a 300 ft chimney). It is interesting to note that contractors have sought to drill near that shot, in order to extract gas from the shale. They were initially restricted to drilling no closer than half a mile. That was back in 2004, but interest in drilling at the site has continued. In the latest development Noble Energy Production is planning on drilling some 78 wells near the site, with DOE apparently having plans to drill closer than the half-mile imposition, though the wells planned in this case are all more than 1.5 miles from the site. The County Commissioners are not amused And, lest there be some concern for gas released at the time, let me quote from the article.

All the gas freed by the nuclear blast was produced and burned off at the surface, Bennetts said. The radioactivity at the site wasn't high to begin with, and since has decreased to below background levels, he said.

The blast formed a sealed cavity underground, according to state and federal authorities. "Even if you drilled a well into that cavity again, there's very little radioactivity remaining to be produced," Bennetts said.

There was some measure of the gas produced

Following the blast, in 1970 and 1971, the companies burned off, or "flared," 430 million cubic feet of gas into the open sky. The commission said that the level of radioactivity in the air surrounding the site did not exceed normal background levels.

Rio Blanco, shot in 1973, was made up of a series of 3 30-KT devices stacked up the shaft, at a depth of 7,000 ft, with the devices actually at 5,840; 6,230 and 6,670 ft. Each device created a cavity that was some 120 ft in diameter, and about 250 ft high. (Against predictions of a 140 ft diameter with a 300 ft chimney.) Fractures from the explosions extended about 200 ft into the rock around the shaft.

The production of gas from the shots was reported to be less than had been anticipated and the levels of radiation higher, so that while the volume of gas that could have been collected "would have been commercially viable," that only held true had the gas been uncontaminated. It was not.

Interestingly there have also been tests of this technology in the Former Soviet Union and when I wrote about gas fires in Turkmenistan there was a comment by Syndroma who posted pictures of devices, which I am reposting here. Also noting

As to extinguishing of gas fountains: 1 in Turkmenistan, 2 in Uzbekistan, 1 in Ukraine (objective not achieved). Also in Ukraine, there was 0.3 kt explosion to alter the geology of coal mine, to make it safer for the miners. Objective achieved. Later, coal was extracted up to 70 meters from the chamber. No excess radioactivity detected.

Of ~150 peaceful explosion only 4 turned out "nasty" (contamination of the surface).

Soviet weapons that could be used in gas and oil well stimulation (from Wonderful Russia via Syndroma)

Syndroma also posted pictures of the result of three shots to generate a trench which I am also moving here. This was the model of the crater:

And this was the resulting crater that was achieved.

Results of the excavation when 3 nuclear devices were used to excavate a trench in the Soviet Union (Syndroma) (You can see the site on Google Earth at 61 18 16.93, 56 35 55.77)

There is more information on the Soviet Program here.

However our purpose is to look at the development of reserves and their contribution to the marketplace within the foreseeable future. Particularly within the next fifteen years, when we can assume that the shortages of supply will become evident, it can, I think, be realistically assumed that there can be no use of nuclear devices to enhance oil shale recovery out West.

At the same time, the toughness of the rock its strength and behavior under mechanical attack make machine mining of the shale a likely impracticality on a sufficient scale to produce perhaps much more than 100,000 barrels a day within that time frame. That judgment on my part is based also on the need to regenerate the capital for the program, reconstruct the facilities and get through all the necessary paperwork.

There are alternate methods for mining the material, including those that are used in conventional metal mining of large-scale surface and underground deposits. However, the mining of something that can generate high levels of potentially explosive gases, if very large scale fracturing and blasting is undertaken, creates levels of risk that will make development of such plans a lengthy process if carried out underground. The mining of Gilsonite for example, was only realistically achieved when the hydrocarbon was mined using high pressure waterjets. But the strength of the oil shale makes the conventional use of that technique impractical - even if it were allowable, which is conjectural.

With these prospects being diminished, the only likely potential for oil shale to have a significant impact in the next fifteen years is likely to be either through some smaller scale in-situ retorting or possibly through a surface mining approach . I will discuss these in the next two posts on the subject.

Temperature data for Kansas - does it help?

Well this is the third in what was not planned as a continuing saga. So far some significant climate assumptions haven’t held up so well on examination, so today I am moving from the data for Missouri into Kansas. And the first hypothesis we will look at is that the data and trends for Kansas are the same as for Missouri. As a subsidiary I will put the two sets of data together, and with a total of around 60 stations, see if this improves any of the statistics that we looked at earlier.

Going through the same process that I followed in putting together the data for Missouri, there are 31 stations in the USHCN data base, and with just a little bit of judicious editing I can use the same format that I have already developed to start putting the different plots together. There are in addition 3 stations in the GISS network (Wichita, Topeka and Concordia). The difference between Missouri and Kansas is that while the former has all the GISS stations in the larger metropolises the Kansas GISS data does include one rural station (Concordia – listed as rural in GISS).

Now there is a second modification to the procedures, since I don’t have a map of Kansas from which to get the census data. Instead I went to the Internet, and, for consistency, used the information from the series of city data that can be found on the Web. For example, if I seek “population Anthony Kansas” the top site is www.city-data.com/city/Anthony-Kansas.html. There are similar sites for all the places in both the USHCN and GISS stations, and, for consistency therefore I used the population numbers from this series of sites. (The data is given for 2008).

I got the information on which were the GISS sites in Kansas by using the list provided by Chiefio and as I noted these are in Wichita, Topeka and Concordia. I also added the station height information (from a Google search under “elevation Wichita Kansas” ), since we are moving closer to the Rockies.

So, if you remember there was no significant warming in Missouri over the last 114 years (the data sets are from 1895 on). My initial hypothesis is that this is also true for Kansas. For our purposes an r-squared value of less than 0.05 is considered not to be significant. (I explained this a little last week). And the data says:


And so Kansas is not showing the same trend as Missouri. Here there has been a significant warming over the past 114 years. So how about the other hypotheses that we looked at in that earlier post?

First of all is there a difference between the GISS stations and the overall average for the state. In Missouri that was a 1.19 degree F difference between the GISS stations and the rest. In Kansas this is, on average only a 0.27 deg F difference. Looking at the trend in the data over the years, we find:


And this is also not entirely expected, if one follows conventional UHI theory, since the two largest stations are in the GISS trio, and one might have thought that this would have led to an increase in the GISS temperatures over the rest of the state, which is largely rural.

However, if you remember from the Missouri data, there was a logarithmic relationship between temperature and population, which gave a greater temperature change as small towns grew, over larger city changes. Thus if Kansas, a largely rural state, was seeing a greater proportion of growth in its smaller communities then perhaps this would explain the change.


The significance is still rather low (since as Luis has pointed out, working with data from the rural states reduces the sample size for larger communities). But if we combine the two data sets, what does this do to the correlation?


Now, with more data, there is a significant correlation between population and temperature.

So let’s have a look at a couple of other parameters, there was a very strong (r-squared 0f 0.8) correlation of temperature with latitude, but not much of a correlation with longitude. How does that stand up for the Kansas data?


Hmm! The correlation isn’t nearly as good. So maybe there is another factor coming into play – how about longitude, which was not significant in Missouri?


I suppose this makes a bit of sense. The further west we are going the higher, since we are approaching the Rockies. So after inputting the elevation of the stations we can see if that gives us the same correlation:


And it does not!

Which means, I suppose, that we had better continue this investigation, and move the data acquisition another state West – which was not what I expected when I started writing this, but we’ll leave that investigation until next week.

And one last bit of curiosity, how do the standard deviations hold, over time, with the new state data?


Well we are still getting that improvement in quality with time, which, as I explained initially, may be due to the change from manually reading thermometers to the automated systems being introduced. We will have to see how this holds up as our search for meaning in the data continues.

P.S. As with all the information in this series, if you want a set of the data please let me know, through comments where you want it sent.

Of Graduate Starting Salaries and the underlying message

While there are many different criteria that cause students to choose different careers, it is a reality that whenever the salaries for those working in the extraction of fossil fuels goes up, so does our enrollment.

So, this being the Olympic weeks, I won’t write a whole lot of comment on this but here are the current top 10 average starting salaries.


Given that the mining and petroleum industries were hit badly after the mid 80’s with a drop in demand for fuel, given the global availability of cheap oil, for 2 decades salaries and the need for graduates were both very limited.

Thus when the last upturn in demand came along, there were not a lot of qualified engineers in the system as it regrew, particularly those in the middle levels of management. And those of us who were around before the ‘80s are now moving into retirement so that there is a need beyond that which can be met by existing supply from the most critical disciplines at the Universities.

The numbers in the above table are averages, I have heard of more than one petroleum graduate starting at above $100k and mining engineers going out at around $85k, it all depends on the quality of the student, and which part of the industry they aim at getting into. But even in these tough times generally because of the lack of supply there is still a strong demand for graduates. Of course we are now starting to see some of the larger incoming classes starting to work their way through the system and start to graduate and meet demand – but I suspect that the top three will continue to be in that position for a while.

Nuclear weapons and oil shale

There is a distinct possibility that we will see the global supply of oil begin to decline within the next decade. In fact the drop may come significantly quicker than some have previously predicted. As Dr. James Schlesinger, the first Secretary of Energy once noted, the American public operates in either Complacent or Panic mode. Given that we may soon reach the latter condition it could be that we may need access to all that oil locked up in the oil shale somewhat sooner than Shell might get it out (and I'll cover that in a later post). The Administration should, therefore, have a crash plan available in case that need becomes critical. This post is written in that vein. Now before I get into the piece that follows I should explain that I don't hold any particular animus towards the states of Colorado, Utah, Wyoming or Idaho and so when I start talking about disposing of nuclear weapons in those states by making use of them it should be taken as merely a technical discussion (grin).

The need for a relatively rapidly available resource to allow us to continue being able to supply the worlds needs for oil, even as it increases into the future, will require some fairly rapid and agile production of resources, and as I noted in the first post of this series, with some 2 trillion extractable barrels of oil locked up in the oil shales of the above four states, there lies a potential answer to the problem. But conventional means for extraction, particularly the levels of capital required, and other issues that I will discuss later, make it unlikely that these normal means will produce any significant impact on the gap in economic supply that will develop in the near future. The use of nuclear explosives has the potential to solve that problem. And to explain, rather simply how this might be done (as with the other techie talks), I will explain how, conceptually, this might be achieved.

The papers that I am going to take the concepts from were given at the second and third oil shale symposia and are listed at the end of the post. They describe the application of results from over 150 underground nuclear detonations which were carried out as the United States sought to find peaceful uses for nuclear explosives as part of the Plowshare Program. I will also be using 1960's costs since these were used in the papers.

To set the stage, as I have described earlier, the Western oil shales occur in rock with almost no permeability, and the kerogen that is in the rock will, under normal conditions stay there, rather than flowing even when it has the chance. So if the oil (kerogen) is to be recovered two things will be needed. The first is a way of massively fracturing the rock, and the second is the maintenance of some level of heating to liquefy the oil, and then to keep it flowing. Large scale fracture of the rock will, in turn, require the application of massive levels of energy, and here nuclear explosives are in a class of their own. Explosive yields are usually given in kilotons, where a kiloton has the effective energy in a thousand tons of TNT. (A ton of TNT has an energy content of 4,184 Megajoules). At the same time the devices themselves are relatively small. A 250 KT device would be around 20 inches in diameter and about two to four times that long. The cost to place it, and the device itself, was estimated to be around $500,000 in 1965.

The oil shale layers are about 2,000 ft thick, and under an additional cover of 1,000 ft of overlying rock (overburden to mining engineers). If a 250 KT device was placed at the bottom of the shale layer, therefore, and detonated, it could be expected to create a cavity that would be around 400 ft in diameter. Much of the radioactive material generated (anticipated to be tritium) would be fused into the wall of the cavity, or caught in the gas that could be drawn off and collected through the boreholes subsequently used to take advantage of the blast.

The shockwave from the event is anticipated to create damaging surface motion to a distance of 2 miles or so, and be substantially disturbing to 6 miles, however, for our purpose, in the immediate vicinity of the blast it will induce significant fractures in the surrounding, and overlying rock. This will cause the rock immediately over the blasted cavity to collapse, and to fall in until a chimney of broken rock has been formed. This chimney will grow upwards until the bulking of the rock as it breaks (that gain of 60% I mentioned last post) fills the space available. For the 250 KT shot this chimney is estimated to be around 1,000 ft high. Experience suggests that the blocks will break into pieces up to 3-ft in size, though the collapse and internal fracturing may increase their ignition potential. The rock surrounding the cavity will, for a distance of around 3-cavity diameters be fractured with a permeability of up to 1 darcy. (The Ghawar field in Saudi Arabia has an average permeability of 617 millidarcies). Beyond that range, and out to about 6 to 8 radii the rock will continue to be fractured, but with fractures more widely spaced and less useful.

Thus, if the entire area is to be treated, then shots would need to be fired around 3 - 4 cavity radii apart in order to maximize the break-up of the rock. (Say for our hypothetical model this would be around 750 ft). By drilling sets of 5 shot holes to create individual retorts, and grouping these in sets of four, to create a "plant," we could create a production operation for the recovery of the oil. Depending on whether the intent is to optimize the fragmentation of the rock, or the fracturing of the surrounding rock with the patterns, some 240,000,000 to 1,000,000,000 cubic feet of rock will be broken per shot, at a cost of $0.015 to $0.05 per ton.

Which brings up the second advantage of nuclear explosives. About 2.5 months after the shot the temperature at the wall of the cavity will still be around 1,000 degrees F, and some 11 months after the shot it will be around 180 degrees. Since the only place for this heat to go is into the surrounding rock, it will cook the kerogen in the vicinity into oil, with, at the sustaining temperature, a low enough viscosity that it will flow into any adjacent collection point.

And it is here that the advances of the past 40-years come into play, since oil drilling is now capable of drilling a "bottle brush" collection pattern under the cavity in order to access and collect the oil (and some water) as it drains down through the fractures. However drilling will also be required to feed air into the chimney and to turn it into a large-scale retort to complete the transition of the kerogen in the vicinity to oil, and to mobilize it. Based on USBM experiments, some 75-90% of the oil in the shale can be recovered from such an in-situ retort. Where necessary some of the gas produced may also be used, in the later stages of the upward progression of the fire front, to enhance the strength of the fire front and to ensure that it continues to move up through the shale, not only in the chimney, but then also into the overlying and surrounding rock. (The fire can be controlled to either burn up or down what now becomes an extremely large retort).

Using this technique and applying it to each of the plants, that I have just described, it is anticipated that each plant, which would cover an area about a mile in diameter, would produce some 450 million barrels of oil over twelve years, at a production rate per day of 100,000 barrels, assuming a 75% recovery of the oil over the 2,000 ft interval. It is anticipated that with a feed of around 3,000 cfm/ton of air at 50 psi, that the flame front could progress at a speed of between 1 and 2 ft per day. In 1965 dollars, it was anticipated that the operation could make a profit if the oil were then sold to a refinery at a cost of $1.50 a barrel. Oil recovery would, however, be controlled by the quantity of oil in each "retort" layer, and, by the nature of the operation, all the oil would be anticipated to be recovered but at the rate controlled by the layers as they produced. However the process is considered economic for oil shale at grades above 15 gallons/ton with thicknesses of greater than 400 ft.

So just think, when we talk about "the nuclear option" in future, we may have an entirely different concept in mind (/grin).

(Note that, for consistency I changed some of the numbers to reflect use in the 2,000 ft shale column, rather than the 1,000 ft used in some of the example calculations in the papers).
Reference papers for this post are:
M.A. Lekas and H.C. Carpenter "Fracturing Oil Shale with Nuclear Explosives for In-Situ Retorting", 2nd Symposium on Oil Shale, CSM, 1965.
H.F. Coffer and E.R. Spiess "Commercial Applications of Nuclear Explosives, the Answer to Oil Shale?", 3rd Symposium on Oil Shale, CSM, 1966.
M.E. Lekas "Economics of Producing Shale Oil, the Nuclear In-Situ Retorting Method," 3rd Symposium on Oil Shale, CSM, 1966.