Above: Drilling for oil; Or, how and learned to stop worrying and nuke the subsurface
A history of the USSR’s nuclear geo-engineering programs produced by the Lawrence Livermore National Laboratory. [link]
Tag Archive for 'geology'
Next nature featured one of those discoveries to emerge out of archeology that cannot help but give one a smile of pause and a thought that this too, indeed, will pass.
Doggerland is the name of a vast plain that joined Britain to Europe for nearly 12,000 years, until sea levels began rising dramatically after the last Ice Age. Taking its name from a prominent shipping hazard—Dogger Bank—this immense landbridge vanished beneath the North Sea around 6000 B.C.
Like all landbridges, Doggerland seems to have been a pretty busy thoroughfare for ancient hunters and gatherers. But archaeologists hardly gave it a thought until 2002, when a small group of British researchers laid hands on seismic survey data collected by the petroleum industry in the North Sea.
It is thought that the sea level rose no faster than about one or two meters per century, and that the land would have disappeared in a series of punctuated inundations. According to marine archaeologist Nic Flemming, a research fellow at the National Oceanography Centre of University of Southampton, UK. “It was perfectly noticeable in a generation, but nobody had to run for the hills.”
Although hunter-gatherers usually have any sense of ownership, land would have become an increasingly precious resource as the sea rose, which according researchers Clive Waddington & Nicky Miller might have led directly to the development of sedentism and territoriality.
It was not until the fantastic rise in energy prices of the last several years (remember: a decade ago a barrel of crude was less than $15) that companies that do oil exploration and production (E&P) began a serious consideration of extracting the very low grade bitumen (essentially the most expensive part of a barrel of oil to refine, and directly the stuff that holds the stones together in asphalt). When prices looked as if they were heading straight for $100, and even more so when it looked like they were heading straight for $200, companies began investing heavily in the Canadian province of Alberta, which is estimated to hold 1.7 trillion barrels of oil, according to government sources. However, the recent turn around in the direction of oil prices, combined with the banking crisis which is (1) making it difficult to put together financing for exploration projects and (2) creating concerns that the slowing economy will push oil below $70, the price that determines profitability for these projects, has cast the future in doubt. All of that said, the physical process by which oil is extracted from the ground is quite interesting and something that is as mysterious as the magic smoke inside an ipod to most people. So for your edification, take a look at the diagram below:
The above image, taken from an investor presentation given by Petrobank, an E&P company working in Alberta, shows the basic anatomy of a well site.
- The vertical well sections are drilled about 1.5km on average, although they could get as deep as 3-4km
- Once the drill reaches the oil sand deposits, the direction will be changed so that the well will continue horizontally. This is done because the seam containing the oil sand is relatively shallow and the more surface the well can make contact with, the more production that will follow.
- Once the actual hole of the well is drilled, it is shored up with a high pressure casing that maintains the structural stability of the well.
- Following this, the casing is fractured in many places using explosives. This has the double effect of loosening up the surrounding sand formations, allowing the oil to flow more easily, as well as providing more entry points for oil to flow into the casing.
- On the surface, the pump jack helps create the pressure required to extract the heavy bitumen from the ground