The hydrogen / carbon ratio, another proof of the mineral origin of hydrocarbons

In all oilfields and wells it is observed that the hydrogen / carbon ratio increases with depth, showing a loss of hydrogen as the fluid rises and approaches the surface.
For reasons of density, one would imagine that hydrogen-rich compounds, which are less dense, should be found in the upper strata, while hydrogen-poor substances, because they are heavier, should be in deeper zones.
However it is the other way around. The less dense compounds are down while the denser ones are above.
The only logical process that explains this trend of hydrocarbon deposits is the upward migration of hydrocarbons (due to planet degassing) and the separation (usually by preferential oxidation) of hydrogen versus carbon during flow.
T. Gold (2001) argues that this process is due in part to the action of bacteria that live at depth less than 10 km (hyperthermobacteria).
According to this approach, methane and other gases would be found in the lower layers, while heavier hydrocarbons (eg naphthas and liquid oils in general) would be located in the intermediate layers and bitumens and coals in the upper layers.
These processes are explained in more
detail in the following chapters.
From the book "Inexhaustible? Gas and Oil", by D.Anton, Piriguazú Ediciones

Deep hydrogen-rich waters in the Earth crust

Comments by D.Anton

Hydrogen has been found in deep boreholes and fractures. It may appear as hydrogen-rich water or combined with carbon forming methane. Probably in both cases as hydrogen gas dissolved in water or as methane may end surging to the upper sedimentary layers or even to the surface. This article puts emphasis on the hydrogen waters. On the other hand, Thomas Gold has dealt with the role of methane in several of his books and papers (The Deep Hot Biosphere and others).

The article reads as follows:

"A team of scientists, led by the University of Toronto's Barbara Sherwood Lollar, has mapped the location of hydrogen-rich waters found trapped kilometres beneath Earth's surface in rock fractures in Canada, South Africa and Scandinavia.

Common in Precambrian Shield rocks -- the oldest rocks on Earth -- the ancient waters have a chemistry similar to that found near deep sea vents, suggesting these waters can support microbes living in isolation from the surface.

The study, to be published in Nature on December 18, includes data from 19 different mine sites that were explored by Sherwood Lollar, a geoscientist at U of T's Department of Earth Sciences, U of T senior research associate Georges Lacrampe-Couloume, and colleagues at Oxford and Princeton universities.

The scientists also explain how two chemical reactions combine to produce substantial quantities of hydrogen, doubling estimates of global production from these processes which had previously been based only on hydrogen coming out of the ocean floor.

"This represents a quantum change in our understanding of the total volume of Earth's crust that may be habitable," said Sherwood Lollar.

"Until now, none of the estimates of global hydrogen production sustaining deep microbial populations had included a contribution from the ancient continents. Since Precambrian rocks make up more than 70 per cent of the surface of Earth's crust, Sherwood Lollar likens these terrains to a "sleeping giant," a huge area that has now been discovered to be a source of possible energy for life," she said.

One process, known as radiolytic decomposition of water, involves water undergoing a breakdown into hydrogen when exposed to radiation. The other is a chemical reaction called serpentization, a mineral alteration reaction that is common in such ancient rocks.

This study has important implications for the search for deep microbial life. Quantifying the global hydrogen budget is key to understanding the amount of Earth's biomass that is in the subsurface, as many deep ecosystems contain chemolithotrophic -- so-called "rock-eating" -- organisms that consume hydrogen. In the deep gold mines of South Africa, and under the sea, at hydrothermal vents where breaks in the fissure of Earth's surface that release geothermally heated waters -- hydrogen-rich fluids host complex microbial communities that are nurtured by the chemicals dissolved in the fluids. This study identifies a global network of sites with hydrogen-rich waters that will be targeted for exploration for deep life over the coming years.

Further, because Mars -- like the Precambrian crust -- consists of billions-of-year-old rocks with hydrogen-producing potential, this finding has ramifications for astrobiology. "If the ancient rocks of Earth are producing this much hydrogen, it may be that similar processes are taking place on Mars," said Sherwood Lollar.

Other key members of the research team are Chris Ballentine of Oxford University, Tulis Onstott at Princeton University and Georges Lacrampe-Couloume of the University of Toronto. The research was funded by the Canada Research Chairs program, the Natural Sciences & Engineering Research Council, the Sloan Foundation Deep Carbon Observatory, the Canadian Space Agency and the National Science Foundation."

From 

https://www.sciencedaily.com/releases/2014/12/141217141127.htm