Things to know about shale gas
1
The dynamic growth of unconventional gas pro-
duction in the United States over the last decade
has led to a true ‘gas rush’ of the 21st century.
In 2000, shale gas only covered 1% of domestic
demand for natural gas in the USA, whereas by
2010 the figure had grown to 15%, thereby mak-
ing the United States the largest gas producer in
the world. The US Energy Information Adminis-
tration forecasts a further growth of its produc-
tion, with shale gas reaching 49% of total US gas
production by 2035.
In addition to the USA and Canada, other lead-
ers in shale gas prospecting and exploration in-
clude China, Australia, Argentina and Poland,
the latter being a European leader as far as the
number of exploration licences and operators’
activity are concerned.
Generally speaking, natural gas found in nature
can be divided into: gas contained in rocks with
good porosity and permeability parameters (known
as ‘conventional reservoirs’), and gas in rocks,
in which these parameters are very low (known
as ‘unconventional reservoirs’). One of the rocks
that make up unconventional reservoirs is shale –
a type of rock which, over millions of years, develo-
ped at the bottoms of seas and oceans from fine-
grained rock sediments (e.g. silts, clays, and grains
of quartz) and remnants of plants and animals
which inhabited them. Rocks based on clay and
silt or ‘shale rocks’ are, therefore, rich in organic
substances which are a source of natural gas. The
technical term for this type of rock is ‘rock matrix’.
Shale gas, which is found in unconventional res-
ervoirs, is technologically more difficult to produce
(and often less economically viable) than traditional
gas produced from conventional rocks. Its deposits
are often found at depths exceeding 3 kilometres.
However, as far as its properties are concerned,
shale gas is the same as ordinary natural gas, which
is very well known and used on a day-to-day basis.
The difference lies in different properties of the
rocks that contain the two types of gas and, conse-
quently, different ways of extracting the gas.
Introduction
What is shale gas and how do you produce it?
A section of a shale core, where remnants of organic mat-
ter can be seen. Their decomposition resulted in shale gas
being formed.
