The document discusses various unconventional hydrocarbon resources including heavy oil and tar sands, oil shale, gas hydrates, coal bed methane, and shale gas. It provides details on their geology, extraction methods, challenges, and key properties affecting production. Thermal methods like steam injection and electrical heating are used to extract heavy oil and tar sands. In situ conversion process and hydraulic fracturing improve extraction of oil shale and shale gas respectively.

2. UNCONVENTIONAL
HYDROCARBON
By-
Swapnil Pal
IMT Geological Technology

3. HEAVY OIL AND • Known for a long time and was easy to
TAR SANDS exploit for use in small quantities.
INTRODUCTION • In southern California oil was mined from
the early 1860s to the 1890s because the
heavy oil would not flow to the wells.
• Tar sands are sandstone reservoirs which
have been filled with oil at shallow depth
<2 km (<70–80◦C) so that the oil has
become biodegraded. Reservoir rocks
which have been buried more deeply and
then uplifted before the oil migration may
be sterilized at higher temperatures and
are less likely to be biodegraded.

4. HEAVY OIL AND • Tar sand contains asphaltic oil rich in
asphaltenes and resins. It has a high
TAR SANDS content of aromatics and naphthenes
INTRODUCTION compared to paraffins, and a high con-
tent of nitrogen, sulphur and oxygen
(NSO).
• Most of the hydrocarbon molecules
have more than 60 carbon atoms and
the boiling point and viscosity are
therefore very high.
• The viscosity of the biodegraded oil is
very high and the oil must be heated so
that the viscosity is reduced before it
can be produced by drilling wells.

5. HEAVY OIL AND • Heating of reservoir.
TAR SANDS  heating can be achieved by soaking the
METHODS OF reservoir with injected steam. This is
EXTRACTION called cyclic steam injection.
 burn some of the oil in the subsurface.
 heat the oil electrically, possibly
powered by a nuclear reactor to reduce
the CO2 emissions from burning oil to
produce heat.
• Freezing the ground at a distance from
the well.

6. TAR SAND  Oil are also extracted from tar sand.
 The tar sands in Alberta, Canada (Athabasca) of
Middle Cretaceous age (Aptian, 100 million years)
contains 1.7 trillion bbl (270×109m3) of bitumen in
place, comparable in magnitude to the world’s total
proven reserves of conventional petroleum.
 The oil (tar) is very viscous and may be denser than
water (API<10). Only about 20% is close enough to
the surface to be economically mined and the rest
must be heated in place. A cubic meters of oil, mined
from the tar sands, needs 2–4.5 m3 of water.
 Oil may be extracted by steam-assisted gravity
drainage (SAGD).

7. HEAVY OIL RECOVERY METHODS
 Primary Recovery Method
 Cold EOR
 Thermal Production Method

8. THERMAL OIL RECOVERY
Cyclic Steam Stimulation Steam Assisted Gravity Drainage
(CSS) (SAGD)

9. CYCLIC STEAM
STIMULATION
Stage 1:
High pressure steam injected
Stage 2:
Major portion of reservoir is
thoroughly saturated
Stage 3:
Production phase
When production phase declines,
another cycle of stream injection
begins.

10. STEAM ASSISTED GRAVITY
DRAINAGE (SAGD)
 2 horizontal wells are drilled.
 Injected steam forms a “steam
chamber”.
 Steam and gases rise filling the
void left by oil.
 The condensed water and crude
oil or bitumen is recovered to the
surface by pumps

11. STEAM ASSISTED GRAVITY
DRAINAGE (SAGD)
 2 horizontal wells are drilled.
 Injected steam forms a “steam
chamber”.
 Steam and gases rise filling the
void left by oil.
 The condensed water and crude
oil or bitumen is recovered to the
surface by pumps

12. IL
SHALE

13. SALIENT FEATURES
• They are not oils!
• They are usually mudstones and shale, with
a high organic content (TOC), which have
not been buried deeply enough to become
sufficiently mature for most of the
hydrocarbons to be generated.
• The can produce oil after undergoing
crushing and pyrolysis.

14. OIL SHALE Oil Shale Resources V/s Oil Reserves

15. GEOLOGY
• Organic rich sedimentary rock, belongs to sapropel fuel group.
• Oil shale vary in mineral content, chemical composition, age, type of kerogen.
• Low solubility in low-boiling organic matter and generates liquid organic
product on thermal decomposition.
• They differ from bitumen-impregnated rock, humic coals and carbonaceous
shale.
• Maturation of oil shale does not exceed meso-catagenetic.

16. OIL SHALE EXTRACTION
Clayey rock
• Oil shale must be mined.
• After excavation, oil shale must
undergo retorting.
Crushing
• Then it undergoes the process of
pyrolysis.
pyrolysis
Shale Oil

17. OIL SHALE EXTRACTION
PROBLEMS
Clayey rock
o This process adds two extra steps
to the conventional extraction
process.
o Oil shale presents environmental Crushing
challenges as well.
o There's also the matter of the
rocks. pyrolysis
Shale Oil

18. OIL SHALE EXTRACTION
SOLUTION
o Royal Dutch Shell Oil Company has
come up with In Situ Conversion
Process (ICP).
o The rock remains where it is.
o holes are drilled into an oil shale
reserve and heaters are lowered
into the earth.
o The kerogen seeps out which is
collected on-site and pumped to the
surface.

19. OIL SHALE EXTRACTION
SOLUTION

20. GAS
HYDRATES

21. WHAT ARE THEY?
 Gas hydrates are crystalline solids almost
like ice, consisting of gas (mostly
methane) surrounded by water.
 It is stable at high pressures and low
temperatures.
 When gas hydrates dissolve (melt) one
volume of gas hydrate produces 160
volumes of gas.
 The source of the methane is mostly
biogenic, from organic rich sediments,
but gas hydrates may also fill the pores in
sand beds.
 During the glaciations gas hydrates were
more widespread than now and occurred
also beneath the seafloor in basins like
the North Sea.
 Gas hydrates are potentially a very
important source of gas.

22. FEW SALIENT POINTS
ABOUT GAS HYDRATES
• Hydrates store immense amounts of methane, with major implications for
energy resources and climate, but the natural controls on hydrates and their
impacts on the environment are very poorly understood.
• The immense volumes of gas and the richness of the deposits may make
methane hydrates a strong candidate for development as an energy
resource.
• Results of USGS investigations indicate that methane hydrates possess
unique acoustic properties.
• Methane, a "greenhouse" gas, is 10 times more effective than carbon dioxide
in causing climate warming.

23. FEW SALIENT POINTS
ABOUT GAS HYDRATES
• USGS investigations indicate that gas hydrates may cause landslides on the
continental slope.

24. COAL BED
METHANE

25. INTRINSIC PROPERTIES OF
AFFECTION GAS PRODUCTION
• Porosity: 0.1-10%
• Adsorption Capacity: 100-800
SCF/ton
• Fracture Permeability
• Thickness of formation and initial
reservoir pressure

26. SALIENT FEATURES
• Coal is the major source of
methane gas.
• Coal is a low permeability
Coal
reservoir. Almost all permeability cleats
is due to fractures, which in coal
are in form of cleats and joints.
Butt Face
cleats cleats

27. PRODUCTION & EXTRACTION
• Coal beds are an attractive prospect for development because of their ability
to retain large amounts of gas
• The amount of methane in a coal deposit depends on the quality and depth
of the deposit.
• In CBM development, water is removed from the coal bed (by pumping),
which decreases the pressure on the gas and allows it to detach from the
coal and flow up the well.
• In the initial production stage of coal bed methane, the wells produce mostly
water.
• Depending on the geological conditions, it may take several years to achieve
full-scale gas production. Generally, the deeper the coal bed the less water
present, and the sooner the well will begin to produce gas.

28. PRODUCTION & EXTRACTION
• The amount of water produced from most CBM wells is relatively high
compared to conventional gas wells because coal beds contain many
fractures and pores that can contain and move large amounts of water.
• CBM wells are drilled with techniques similar to those used for conventional
wells.
• As with conventional gas wells, hydraulic fracturing is used as a primary
means of stimulating gas flow in CBM wells.
• The methane desorption process follows a curve (of gas content vs. reservoir
pressure) called a Langmuir isotherm.
• As production occurs from a coal reservoir, the changes in pressure are
believed to cause changes in the porosity and permeability of the coal. This is
commonly known as matrix shrinkage/swelling.

29. PRODUCTION & EXTRACTION
The potential of a particular coal bed
as a CBM source depends on the
following criteria:
 High Cleat density/intensity.
 Maceral composition.
 A high vitrinite composition is
ideal for CBM extraction, while
inertinite hampers the same.

30. SHALE GAS
The game changer!

31. INTRODUCTION
 Shale gas refers to natural gas that is trapped within shale formations.
Organic-rich shale which have been buried to depths where most of the oil
and gas has been generated and expelled may nevertheless contain
considerable amount of gas.
 The gas remaining in these shale is present in very small pores and may also
be partly adsorbed on remaining organic matter or its residue (coke) and on
clay minerals.
 The shales have been uplifted and may therefore have small extensional
fractures, but they must be hydro fractured by water injection to increase the
permeability.

32. EXTRACTION
• The gas deposits are usually found in
rocks that have low permeability, ruling
out the possibility of regular drilling.
• The most commonly used method is
called fracking (hydraulic fracturing).
• As opposed to vertical drilling for
traditional gas, in this case horizontal
drilling is carried out.
• What “changed the game” was the
recognition that one could “create a
permeable reservoir” and high rates of
gas production by using intensively
stimulated horizontal wells.

33. TWO MAJOR DRILLING TECHNIQUES ARE USED TO
PRODUCE SHALE GAS
Horizontal Drilling Hydraulic Fracturing
Horizontal drilling is used to provide It is a technique in which water,
greater access to the gas trapped deep chemicals, and sand are pumped into the
in the producing formation. First, a well to unlock the hydrocarbons trapped
vertical well is drilled to the targeted in shale formations by opening cracks
rock formation. At the desired depth, (fractures) in the rock and allowing
the drill bit is turned to bore a well natural gas to flow from the shale into
that stretches through the reservoir the well. When used in conjunction with
horizontally, exposing the well to more horizontal drilling, hydraulic fracturing
of the producing shale. enables gas producers to extract shale gas
at reasonable cost.

34. CONCLUSION
• Conventional oil production has peaked and is now on a terminal, long-run global
decline. However, contrary to conventional wisdom, which many embraced
during back-to-back oil crises in the 1970s, oil is not running out. It is, instead,
changing form—geographically, geologically, chemically, and economically.
• We are approaching the end of easily accessible, relatively homogeneous oil, and
many experts claim that the era of cheap oil may also be ending.
• Many new breeds of petroleum fuels are nothing like conventional oil.
Unconventional oils tend to be heavy, complex, carbon laden, and locked up deep
in the earth, tightly trapped between or bound to sand, tar, and rock.
Unconventional oils are nature’s own carbon-capture and storage device, so
when they are tapped, we risk breaking open this natural carbon-fixing system.
Generally speaking: the heavier the oil, the larger the expected carbon footprint.

35. CONCLUSION
From extraction through final use, these new oils will require a greater amount of
energy to produce than conventional oil. And as output ramps up to meet
increasing global demand for high-value petroleum products, unconventional oils
will likely deliver a higher volume of heavier hydrocarbons, require more intensive
processing and additives, and yield more byproducts that contain large amounts of
carbon.