[MUSIC]
Everything we've been talking about so
far pertains to conventional hydrocarbon reserves.
That means the kinds of reserves in which an oil company can drill a hole and
pump the fluid out of the ground.
That's because the fluid has relatively low viscosity and
because the rock in which it's stored has relatively high permeability.
But there are vast amounts of hydrocarbons on this planet that are not
in conventional reserves, that are either in rocks that lack permeability,
so they can't be pumped easily.
Or occur in a form that is so viscous that it's not possible for
the oil to flow, even if the rock had permeability.
These kinds of hydrocarbons are called nonconventional reserves.
And in this section, we're going to focus on recent efforts
to try to extract hydrocarbons from nonconventional reserves.
And I'll say from the start that it's clear that this is a controversial
process.
There are many people that think it's the future of energy use in the near term.
There are many people that think that it's extremely damaging to the environment and
should be avoided at all costs.
I'm going to try to avoid the issue for better or worse.
I simply want to try to convey what these are and
how the process of extraction works.
Hopefully to provide you with enough understanding so
that you'll be able to make your own decision whether it's good or bad.
Let's start with the three main kinds of non conventional reserves.
They are tar sand, oil shale and shale gas.
Now I'm going to look at each of these in sequence, but
we're only going to talk very briefly about the first two.
It's the third one that's been the subject of so
much excitement in the exploration industry of the past five to ten years,
and so we'll focus more of our time on that.
So what is tar sand?
Well basically, there are certain places in the world,
where large amounts of oil migrated into a reservoir rock.
But once in the reservoir rock, which is very shallow in the crust,
they were attacked by microorganisms and degraded.
In this process,
they underwent reactions that lead to the production of very long molecules.
In other words, tar like molecules.
As a consequence, these hydrocarbons cannot flow very easily.
And even though they occur in a highly permeable host rock, sand or
sandstone, they can't be extracted simply by drilling into them and pumping.
So there are basically two ways the tar sands are extracted.
One is by strip mining them.
Basically, some of the deposits occur so close to the surface,
that it's possible to dig them up with a shovel, load it into giant trucks, and
carry it out of the ground to where they can be processed.
Now the processing requires a lot of energy.
Specifically, they're put into a furnace, where they are warmed up to a high enough
temperature that they become low enough in viscosity that they can flow.
And at that point, they are extracted and separated from the sand
where they can then be cracked to form more conventional types of fuels.