2. CONVENTIONAL AND
UNCONVENTIONAL GAS
Conventional Gas
Free oil and gas
trapped in porous
reservoirs
(usually
sandstone or
limestone)
Relatively easy to
extract
Unconventional
Gas:
Gas trapped in
rocks which is
more difficult to
produce from
such as :
Tight gas
Coal bed
methane
Shale Gas
Why extract
unconventional
oil and gas now?
Developments in
drilling technology
over the last 20
years have made
it economic to
extract
4. WHAT IS SHALE GAS?
Sedimentary
rock and organic
matter (kerogen)
Both source
rock and
reservoir of the
gas
Shale
Stored in three
ways
Thermogenic
and biogenic
generation
Gas
5. ENERGY INDEPENDENCE
Sources: IEA and EIA
USA China
2014 total energy import 25% 19%
Gas percentage produced with shale
in 2015
50% Work in progress
6. USA become a gas
exporter
Shale gas & tight oil
13.6 Tcf in 2015
to 29 Tcf in 2040
8. ECONOMICAL ISSUES
30% fracking companies went bankrupt in 2015 due to the oil low price
At the same time technology improvements leads to higher rates of recovery at lower costs
Oil price - WTI [USD/bbl]
9. EUROPE POSITION
Poland has european largest
reservoirs and those are being
investigating
Independence from
Russia
Environmental
Effects
10. THE WELLBORE
Location of
the site
Vertical drilling
(mud )
Casing (conductor,
surface,
intermediate,
production)
Cement
Kick off point
11. THE WELLBORE
Angle drilling process in
order to get horizontal
mining along the shale
layer (eventually in
several directions)
Again cement to seal the
production casing
The well is complete:
casing and cement isolate
the freshwater zone and
the surroundings from the
wellbore, avoiding any
kind of leakage. The
drilling machine is no
longer needed.
12. HYDRAULIC FRACTURING
It’s a mining technique that is
used to release the gas
trapped in shale formations.
The first step after the drilling
process is the perforation of
the production case using a
perforating gun
13. HYDRAULIC FRACTURING
Fracking can be described as a
sequence of three stages:
1. PAD: high pressure fluid is pumped
down through the well and the
perforation holes in order to
fracture the formation
14. HYDRAULIC FRACTURING
2. PROPPANT STAGE: proppant is
added to the fluid in order to keep
the fissures open (sand, bauxite,
ceramic balls)
2. DISPLACEMENT: flush the
previous sand laden stage in order
to clean the pipe and allow the
extraction of gas.
15. EXTRACTION OF THE GAS
Hydraulic fracturing is completed
Fluid is carried out of the pipe
Permanent production well head is
installed
17. CONTAMINATION OF WATER SUPPLIES
Ways of contamination:
Propagation by fractures
Wellbore leakages
Solutions:
Fingerprint and seismic measurments
API directives
18. WASTE WATER DISPOSAL
•
Flowback water
Methods of
disposal:
Underground
injection
At municipal
facilities
Reuse
147,000 counted injection
wells
Over 250 milion cubic meters
pumped each year
19. SEISMIC RISK
• Caused by fluid injection
• Increased number of earthquakes with
M>3:
• Increase in magnitude
• Most powerful was 5.6 M
24 193