Sunday, February 28, 2010

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.


  1. The link I dug up about Gasbuggy said the DOE's conclusion was it yielded radioactive NG lower in btu's; also this for gas not recoverable by those darn "conventional means." But that was back in 1967. Negative? I suppose, but nothing like the guy suggesting we use nukes for population reduction, or all the analogies about junkies.

    I'd expect that nuking kerogen would just result in an out of control flame front. Doubtless in a desperate enough situation it would be proposed anyway. But who knows? Program #7 included "25 explosions for intensification of oil and gas debits." Debit in this case I assume means flow rate? Syndroma says nukes worked best as an over-the-top form of seismic surveying.

  2. That was also the apparent conclusion from some of the Soviet reports, though I have to admit not to chasing after this topic with a whole lot of energy, since I don't think it is going to be much more than an intellectual curiosity.

    But then I have been wrong on numerous occasions in the past.

  3. I once had an opportunity to talk with a physicist who had taken part in one of those tests on a tight gas reservoir. After hearing his description of the (impermeable) glass-lined chamber they created in the formation, I was left wondering if it might have been more effective to have set off the explosion at some depth below the tight gas sand -- aiming to fracture the rock rather than fuse it.

    You are undoubtedly right that the current western Political Class can no more imagine constructive use of nuclear explosions than they can imagine a balanced budget. But they don't rule the world.

    China, India, Pakistan, Iran, Russia, Brazil, Kazakhstan -- there are a number of current & future nuclear powers who would have little hesitation in using a technical method to supply themselves with essential fuel, if the need was upon them. There is a high probability that nuclear-enhanced hydrocarbon production lies somewhere in the global future.

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