Shale Gas

Shale Gas
What is shale gas?
Shale

Sedimentary rock deposited in low energy marine and lake environments

Composed by layers of clay-size mineral grains and organic matter
Natural Gas

Fossil fuel originated from plant, algal or other organic remains

Composed primarily of methane - up to 95%
Is it different to conventional gas?
Shale gas is a type of unconventional gas

Both conventional and unconventional gas have the same chemical composition

They mainly differ in the geology and physical properties of the reservoirs in which they are stored
Conventional vs Unconventional
How is it produced?
What are the benefits of using it?
What are the risks?
Unconventional reservoirs have very low permeability. They can only be produced by some extraordinary completion, stimulation and development practices



Shale gas can be economically produced by the conjunction of:

Horizontal Drilling - to maximize pay zone exposure to the well

Hydraulic Fracturing - to increase the permeability of the reservoir by creating or restoring small fractures in the rock
Tight Gas Sands
Shale Gas
Coalbed Methane
Gas Hydrates
Typical oil reservoir rocks, such as sandstones, have permeabilities between 100 and 10,000 mD
Shale Gas reservoirs have permeabilities of less than 0,001 mD.
(between 10,000 and 1,000,000 less permeability)
Further Challenges
Production technology

Water management

Specific regulation and legislation

Monitoring systems

New proppant materials

Use of non-water based fracturing fluids
Reduction of Greenhouse gas emissions

Security of supply

Increase in tax revenues

Gas prices

Job creation

Stimulation of national manufacturing industry
Where is it?
Shale gas in the World
Shale gas in the UK
Rank Country of technically recoverable Shale Gas (tcf)

1 China..................1,115
2 Argentina.........802
3 Algeria................707
4 US.........................665 (1,161)
5 Canada...............573
6 Mexico...............545
7 Australia............437
8 South Africa....390
9 Russia.................285
10 Brazil.................245
Others...................1,535
World Total........7,299 (7,795)
Open pits
Surface pollution

Groundwater contamination

Methane emissions
Inadequate well design and/or poor construction
Groundwater contamination

Methane emissions
Induced seismicity
Surface damages

Casing deformation
Silica exposure

(US)
900,000 p/y
30,000 p/y
500 p/y
100 p/y
20 p/y
1 p/ 5 to 10 years
Water sourcing and use/re-use
Fluid transport
Public disclosure of fracking fluid composition
Flowback disclosure
Fluid storage
Fluid treatment and disposal