Page 99 - Oil and Gas Production Handbook An Introduction to Oil and Gas Production

experimenting with direct electrical heating rather than e.g. steam injection.
Extraction cost is currently around 25-30 USD per barrel.

7.1.4 Coal gasification and coal bed methane
Coal is similar in origin to oil shales but typically formed from the anaerobic
decay of peat swamps and relatively free from non organic sediment
deposits, reformed by heat and pressure. To form a 1 meter thick coal layer,
as much as 30 meters of peat was originally required. Coal can vary from
relatively pure carbon to carbon soaked with hydrocarbons, sulfur etc.

It has been known for decades that synthetic oil could be created from coal.
Coal gasification will transform coal into e.g. methane. Liquefaction such as
the Fischer-Tropsch process will turn methane into heavier liquid alkenes.
(C nH 2n+2).

In addition, coal deposits contain large amounts of methane, referred to as
coal bed methane. It is more difficult to produce gas from coal than natural
gas (which is also largely methane), but coal could add as much as 5-10% to
natural gas proven reserves.

7.1.5 Methane hydrates
Methane hydrates are the most recent form of
unconventional natural gas to be discovered
and researched. These formations are made
up of a lattice of frozen water, which forms a
sort of cage around molecules of methane.
Hydrates were first discovered in permafrost
regions of the Arctic and have been found in
most of the deepwater continental shelves
tested. The methane originates from organic
decay.
At the sea bottom, under high pressure and low temperatures, the hydrate is
heavier than water and cannot escape. Research has revealed that this form
of methane may be much more plentiful than first expected. Estimates range
anywhere from 180 to over 5800 trillion scm.

The US Geological Survey estimates that methane hydrates may contain
more organic carbon than all the world's coal, oil, and conventional natural
gas – combined. However, research into methane hydrates is still in its
infancy.

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