What is fracking? What is retorting? How can it be done? Why should India go for extracting the shales? This is a brief introduction to all the answers you might be wanting regarding shale gas and shale oil...... After all this is a research in progress in which India has a huge potential!

1. EXTRACTING THE SHALES
-VISMAY HARANI
-Guided by Dr. K.S. AGRAWAL

2. The Great U.S. Success story
Indian Energy Scenario
• It imports about 75% oil that it
consumes.
• During 2011-12 country imported
171.73 MMT crude oil. Crude oil
production during 2011-12 at 38.09
million metric tons.
•
•
•
•
•
The International Energy Agency
(IEA) has predicted that the U.S.A.
would become the world’s largest oil
producer by 2020.
And a BIG CONTRIBUTING FACTOR IS
SHALE OIL and the SHALE GAS.
Shale gas accounted for 39% of total
natural gas production in 2012. With
25.7 cubic feet per day, it makes
U.S.A. the largest producer of shale
gas.
Canada obtains 15% of natural gas
from shale oil.
China holds the world’s largest
potentially recoverable reserves of
shale gas with estimated reserves of
1,115 trillion cubic feet versus 665
trillion cubic feet for the US.

3. SHALES
Oil Shale
Gas bearing Shale Rock
Black organic shales are the
source rock for most of the oil
and gas reservoir.
Much of the Shale Gas is
obtained from these rocks.
Gas is obtained from these
rocks by fracking/(fracturing +
cracking).
The term oil shale generally
refers to any sedimentary rock
that contains kerogen .
Over long periods of time, heat
and pressure transformed the
materials into oil shale in a
process similar to the process that
forms oil; however, the heat and
pressure were not as great.
Oil from the Oil Shales is
obtained by Retorting.

4. FRACKING
• Natural Gas produced from shale is
called unconventional gas, while
that produced from sandstones
and lime stones is called
conventional gas. In both the cases,
methane is produced.
• Method of extracting the gas
directly from the source rocks is by
pressurized hitting of water to split
the rocks open which is called
Fracking.
• Fractures are created in the source
rocks allowing the passage of gas.
Once the fractures are created,
small particles of sand are pumped
into them to keep the fractures
open.
• Fracking involves no explosives.

5. What is Kerogen and what it is not!!
• It is the complex carbonaceous (organic) material
that occurs in sedimentary rocks, carbonaceous
shales, and oil shales.
• It is for most part insoluble in the common organic
solvents.
• And contradictory to popular opinion, there is a
distinct possibility that it may not be a precursor to
petroleum but one of the by-products of the
petroleum generation and maturation processes.
• It is composed of two parts:1. 80-95 wt% non-porous, impermeable mineral matrix
2. 5-20 wt% organic material

6. Retorting the Solid Oil Shales
• Explosives are positioned at
suitable places inside the
reservoir, which are
exploded.
• Large oil shales are
converted into smaller rock
fragments (or rubble)
• This is called a rubblized
bed.
• Rubblized shale is heated at
a large
temperature, thermally
decomposing the kerogen.
Two ways in which mining and
processing of oil shale can be done:1. Underground mining using the roomand-pillar method or surface retorting
 It involves mining of ores
 It is a well known technology
 Large environmental effect like: Popcorn effect
 Large open mines
 Emissions
2.



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In Situ Retorting
Underground conversion
Research in progress
Lower environmental effect
Not commercially proven

7. Surface Retorting
Hot Recycled Solids: Alberta Taciuk Processor
It delivers heat to the oil shale by recycling
hot solid particles—typically oil shale ash.
It employs rotating kiln or fluidized
bed retorts, fed by fine oil shale. The recycled
particles are heated at 800 °C and then mixed
with the raw oil shale to cause the shale to
decompose at about 500 °C.
Oil vapor and shale oil gas are separated from
the solids and cooled to condense and collect
the oil.
These are also called Ex-situ
technologies.
There are five such methods:1. Internal Combustion
Mined shale is fed from the top
of the chamber, hot gases from
the bottom, resulting in
retorting.
2. Hot Recycled Solids
3. Conduction through Wall
Direct heat transfer through
hot gases doesn’t take place,
but heat is transferred via
conduction through walls.
4. Reactive Fluids
Extraction through reactive
fluids is being tested currently.
5. Plasma gasification
Oil shale is bombarded by ions
to produce oil and gas. Water is
not used in this method.

8. IN SITU COMBUSTION
•In vertical in situ retorts, a flame front
moves downwards through a rubblized
bed to liberate shale oil, off gases and
condensed water.
•There are two types of in situ retorts :
1. True In situ retorts
• Burning a portion of oil shale
underground, to produce the heat
needed for retorting the remaining
oil shale
• It is difficult to maintain and control
the underground combustion
process
2. Modified In situ Retorts
• A volume beneath the retort zone is
mined and sent for surface retort
which in turn improves the access to
air for carrying out combustion and
supporting the flame front.

9. THERMALLY CONDUCTIVE IN SITU CONVERSION •The process involves heating
underground oil shale, using electric
heaters placed in deep vertical holes
drilled through a section of oil shale.
•The volume of oil shale is heated
over a period of two to three
years, until it reaches 650–700 °F, at
which point oil is released from the
shale.
•The released product is gathered in
collection wells positioned within the
heated zone.
•An underground barrier surrounding
the extraction zone ‘freeze wall’ is
created by pumping refrigerated fluid
(brine at -10 0C).
•Freeze wall prevents ground water
from entering the extraction
zone, and prevents the hydrocarbon
from leaving its perimeter.

10. COSTS
The following costs must be taken into
consideration:•Drilling Cost
In a ten acre plot, there are 250 heater
wells and 80 producer wells. Total cost
is $ 26.4 million ($80,000 per well)
•Refrigeration Costs
Q = 5*10^6 KW.
Purchase cost : $12.5 million
Operating Cost: $3.2 million/day
•Pumping Costs
Now 80 centrifugal pumps are used to
remove ground water trapped in the
freeze wall at a rate of1.6 million
gallons/hr for a period of 2 weeks.
Cost of Pump: $83,000/pump
$120,000 /day needed for electricity
•Heating Cost
$80,000 per heater
Electricity cost: $80,000/day

11. Environmental Pollution
LAND USE AND SOLID WASTE
MANAGEMENT
WATER POLLUTION
Disposal of spent shale is a menace as it causes
water pollution.
A good oil shale yields only 20-30 gallons of oil
per ton of rock, with 85 to 90% of the weight of
the original rock appears as spent shale.
When water falls on the spend shale, some
material is leached out, which will in turn pollute
surface water as well as ground water.
AIR POLLUTION
 Oil shale-fired power plants causes emissions
of
gaseous products like nitrogen oxides, sulfur
dioxide and hydrogen chloride, and the airborne
particulate matter (fly ash).
Due to kerogen, the emission of CO2
increases, giving rise to global warming.
Surface mining and in
situ processing requires
extensive land use.
Mining, processing and
waste disposal require land
should be far away from
high density population
areas.
It will harm the
biodiversity.
Sub-surface mining might
cause caving-in of the
mined out are.

12. India : Shale Scenario
• India has huge shale
gas deposits in
Vindhyan, Gondwana,
Cambay, Rajasthan
• On the other hand, it is
estimated that greater
than 15 billion tons of
oil is present in oil
shales.
• Oil Shales are found in
north east India, Assam
and neighboring areas
of Arunachal Pradesh.
Thank You