Thanks, Keith, for the very interesting discussion of something I didn't know about, these methane/propane hydrates.
But my friend was discussing oil (petroleum) -- not methane.... I'll ask him for a source. Cheers, Lawry > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Keith Hudson > Sent: Wed, September 03, 2003 12:53 PM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Bacterial methane (was RE: [Futurework] There ain't no hydrogen > > > Hi Lawry, > > A further (shorter) tutorial is in order I think! > > At 09:59 03/09/2003 -0400, you wrote: > >Greetings, > >Normally, I don't follow energy discussions... > >But, I have a query. > >Recently, a most respected and technically qualified friend visited, and > >among the other ideas he laid on me was the following: > >Oil (petroleum) is not created by the decay of biomass over eons. It is > >created by some form of bacteria. > > I think maybe your friend is confusing two (fairly) separate sources of > natural gas. As far as I'm aware, all the oil and gas fields which have > been prospected (and they are known now in great detail all over > the world, > even in the Antarctic) lie at ancient river estuaries, even if some of > these are now under the sea (as in the North Sea). The oil and gas is a > product of the breakdown of the immense amounts of vegetation that were > deposited in these estuaries from discarded vegetation from dense > tropical > rain forests of thousands of square miles in area. Each of these deposits > would be like a gardener's compost heap -- but many square miles > in extent > and maybe miles deep! If sedementary rocks, such as sandstone, were > subsequently laid down on top of these compost heaps then as the methane > and propane (or the oil) were produced they would diffuse into the > micro-crevaces in the overlying rock. And this is what is drilled into in > your typical oil and gas fields. The gas or oil springs out or > leaks out -- > or is forced out by injecting high pressure water. > > But natural gases, such as methane and propane, as a result of anaerobic > decomposition, would also be produced by bacteria and small > insect life in > even moderately poor soils and this would happen across very > large portions > of the earth's surface, not just in the concentrated rain > forests. If these > layers were subsequently capped with water then, as the gases > were produced > they would diffuse into the water and if, further, very great > pressure were > exerted on these layers, or if they became very cold, as in permafrost > regions, then the gases would be trapped within ice crystals. These > deposits are called methane (or propane) hydrates. These are > found in very > extensive areas in deep water adjacent to continental shelves > (that is, in > areas where a previous land surface has subsided), and also, nearer the > surface, in northern permafrost tundra regions. The amount of methane in > these deposits is immense. Estimates of the amount of methane > vary between > quantities between 20 and 200 times the amount of natural gas in orthodox > rock-type gas fields -- more than enough to keep the whole world > going for > at least hundreds of years. > > However, there are two big drawbacks. For one thing, most of the > deposits, > though huge, have very low concentrations of methane and are not economic > to extract. For another, the deposits would probably be very dangerous to > exploit because the methane hydrates are liable to melt and > collapse in an > uncontrollable way. Under the sea in particular, the methane hydrate > layers, perhaps hundreds of feet thick could suddenly start > dissolving into > a thick sort of water, causing immense slippages of nearby rock and > coastlines. Already, oil drilling rigs have disappeared when ocean floors > have suddenly given way when the drill head reached the tip of hydrate > layers. Any deeper penetration could have caused major landslides > -- of the > sort that could drop hundreds of miles of coastline (and many > miles inland) > into the sea and produce earthwauke-type tsunami waves that could travel > for thousands of miles across oceans. There is much evidence that these > sort of immense landlsides have occurred in times past when sea levels > dropped during ice ages and the pressure on the methane hydrate > levels was > reduced. > > In short, methane hydrates are strictly off-limits! Too "hot" to handle. > There may be places where it is known that the hydrates are both highly > concentrated and are in restricted undersea valleys where they are hemmed > in and therefore perhaps not too dangerous to tap into but, even so, the > oil corporations, desperate though they are for more oil and gas > resources, > are not spending any money on research and development of these resources > and are leaving it to governments, which carry out modest research > programmes from time to time. Another possibility that has been > considered > is that if there were a collapse of a major methane hydrate > field, then the > atmosphere could become saturated with methane -- and this is a > greenhouse > gas that is 10 times more powerful than CO2 in its temperature-blanketing > effect. > > That seems to be the picture and this is why, despite the quite enormous > quantities of methane down there, it never enters into scenarios for > mankind's energy future, corporate or governmental. > > KSH > > >The implications are that oil may be an > >unlimited resource, and that we are not drawing down on a > resource that will > >become increasingly rare and expensive. Also: productive and > long-term oil > >deposits are likely to be more common than commonly thought. > > > >My reaction was skepticism, but this friend is no lightweight, has a very > >strong engineering and scientific background, and carries on an > active and > >personal worldwide technology and science scan. > > > >Your thoughts? > > > >Cheers, > >Lawry > > Keith Hudson, 6 Upper Camden Place, Bath, England, > <www.evolutionary-economics.org> > > _______________________________________________ > Futurework mailing list > [EMAIL PROTECTED] > http://scribe.uwaterloo.ca/mailman/listinfo/futurework > _______________________________________________ Futurework mailing list [EMAIL PROTECTED] http://scribe.uwaterloo.ca/mailman/listinfo/futurework
