Geoheresy

The distortion of science for ideological purposes has a long history, and the results are generally ugly.

Saturday, November 11, 2006

 
ECORELIGION and ABIOTIC OIL

It seems pretty clear our climate-changers are members of a new religion judging by the resistance to published refutations of BOOP (Biological origin of Petroleum).

The most bizarre statement so far is that the Fischer Tropsche process is occurring at the base of the crust to form hydrocarbons from buried organic matter.

Let's get a few facts straight - generally speaking the geothermal gradient is about 23.5 deg C per km, and higher in volcanic regions. Pressure also increases with depth of burial and sedimentary rocks that do become buried might reach a very low metamorphic grade, perhaps lower greenschist?

Where is oil found? from surface to depths of about 5000 metres and a useful of recovery versus depth is here. This places a limit to which sediments can be buried to, ie about 5ooo metres down. Sedimentary basins can get up to 15km in thickness as shown here.

The Fischer Tropsche method simply combines carbon monoxide and hydrogen using either a nickel or iron catalyst to produce hydrocarbon synthesis at 150 Bar and 700 K (or 427 deg Celsius).

Now 150 Bar represents a depth of burial of about 5km but a temperature of 427 degrees Celsius suggests a depth (using 23.5 deg C/km) of 18 km.

We have a small problem here, because for the FT method to work as believed by some BOOPERS then at this temperature the metamorphic grade is based on mineralogy lower amphibolite. However gas fugacity in the rock is also important and the appearance of key metamorphic index minerals can cause quite some confusion.

In any case if we assume a depth of 150 bar (or about 5km) then assuming the average geothermal gradient of 23.5 per km, implies a temperature of 5*23.5 or 117.5 degrees Celsius, and at that temperature the FT process does not proceed.

Petroleum science solves this problem by invoking hundred of millions of years for the initial organic matter to spontaneously transform into petroleum. This is much like proposing that if we get the feedstock for the FT process and pressurise it to 150 bar but only raise the temperature to 117.5 degrees Celsius and then wait for 100 million years, hydrocarbons will be produced.

This is of the "Do A" then a miracle occurs "creating B" type of logic. The miracle occurs during the 100 millions or more years of burial.

The deepest sedimentary basins are 15 km, and again using the geothermal gradient used above, expected temperatures are 352 degrees Celsius. Pressures? About 4000 bar.

Metamorphically that would place the host rocks into lower amphibolite facies but we don't find oil in metamorphic rocks do we ?

A more complete refutation of BOOP is available at Gas Resources Corp.

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