By Prof. Dr. Hassan Z. Harraz hharraz2006@yahoo.com

Oil Shale

• Petroleum: A general term for all naturally occurring hydrocarbons (hydrogen + carbon)

• Solid Hydrocarbons: Asphalt

• Liquid Hydrocarbons: Crude oil

• Gas Hydrocarbons: Natural Gas: methane, butane, propane, etc.

What is petroleum?

Organic Matter

• Sedimentary rocks rich in organic matter (~ 0.5 - 2% by weight)

• Most commonly microscopic marine material, but it can be land based material

• Organic material cannot decay too much (It has to keep its carbon).

Source Rocks (i.e., Oil Shale)

The simplest hydrocarbon is Methane (CH4)

April 13, 2012 HZH 2

The origin of fossil fuels Biomass energy in general, starts

with photosynthesis.

Origin and Habitat of Petroleum

Fossil fuels : Local large concentrations of organic matter in

sedimentary rocks, in the form of coal, oil or natural gas.

Oil Shale

April 13, 2012 HZH 3

Origin and Habitat of Petroleum

Many organic carbon-rich marine and lake

shales never reach the burial temperature level

at which the original organic molecules are

converted into hydrocarbons forming oil and

natural gas. Instead, the alteration process is

limited to certain wax-like substances with

large molecules.

This material, which remains solid, is called

kerogen, and is the organic substance of so-

called oil shales.

Kerogen can be converted into oil and gas by

further burial by mining the shale and

subjecting it to heat it in a retort.

April 13, 2012 HZH 4

In nature, crude oil deposits are occurring in two different modes, namely:

i) Conventional oil reservoirs

Figure shows Crude oil reservoirs; Hydrocarbon trap; traditional oil well methods.

ii) Unconventional oil reservoirs.

Figure show oil shale and fossil in oil shale from Messel pit, south of Frankfurt am Main, Germany.

Oil that has escaped to the surface and extracted by

mining techniques. Unconventional deposits, such as:-

• Marsh gas , • Coal-bed methane, • Tar sands, and • Oil shales.

Occurrence of Oil and Gas

Oil Shale Considered a source rock for

conventional crude Reservoir resources April 13, 2012 HZH 5

This articles aims to shows some light on the oil shale (i.e., Burn rocks or Source Rocks) as the important types of unconventional oil deposits in the earth.

Producing energy from rock that burns

is entering into a new research and

development phase.

Can these processes now in the

experimental stages unlock some of oil

shale’s enormous potential ?

April 13, 2012 HZH 6

Oil Shale

(Burn Rocks or Source Rocks)

Silty marlstone containing relatively large amounts of organic matter called kerogen

Kerogen : heated produce oil and natural gas

April 13, 2012 HZH 7

Figure shows mining method to exploited oil

shale deposits

Figure shows extracting oil from oil shale deposits oil

Most of the world's oil reserves are recorded as unconventional

crude oil.

April 13, 2012 HZH 8

OIL SHALE VARIETIES

Based on mineral content of Oil shales, three categories can recognized namely: – i) Carbonate-rich oil shales • content a large amount of carbonate minerals (such as calcite and dolomite)

that mixed with oil shale, • have usually the organic-rich layers sandwiched between carbonate-rich

layers. • are hard formations that are hard and resistant to weathering. • are difficult to process using ex-situ methods.

ii) Siliceous oil shales • are usually dark brown or black shales. • are not rich in carbonates but rather in siliceous minerals (such as quartz,

feldspar, clay, chert and opal). • are not as hard and weather-resistant • may be better suited for extraction via ex-situ methods.

iii) Cannel oil shales • are usually dark brown or black shales, • consist of organic matter that completely encloses other mineral grains. • are suitable for extraction via ex-situ methods

April 13, 2012 HZH 9

Fig.13: Shows Woodford Shale Formation at Oklahoma, USA.

Fig.14: Show tar sand in association with asphalt in

SeepViola Limestone, Oklahoma – USA.

Fig.15: Shows coals and Coaly Shales at San Juan Basin,

New Mexico- USA.

April 13, 2012 HZH 10

OIL SHALE CLASSIFICATION

There are varying classifications of oil shales depending: on their mineral content, type of kerogen, age, depositional history, and organisms from which they are derived.

Figure shows Van Krevelen diagram which showing types of kerogen and pathways for

generation of methane and elimination of carbon dioxide and water during coalification.

Liptinite corresponds to types I and II kerogen, vitrinite to type III, and inertinite to type IV.

High quality

April 13, 2012 HZH 11

Table Classification of oil shales by environment of deposition (Hutton, 1987)

Terrestrial

(Type III, low quality (H/C))

Lacustrine

(lake-bottom-deposited)

(Type II)

Marine

(ocean bottom-deposited)

(Type I, High quality (H/C))

Cannel coal

Lamosite;

Torbanite

Kukersite;

Tasmanite;

Marinite

The most used classification of oil shales was developed between

1987 and 1991 by Adrian C. Hutton of the University of Wollongong, based

on the environment where the initial biomass was deposited .

Hutton's classification scheme has proven useful in estimating the yield and

composition of the extracted oil .

According to this classification oil shales are designated as:-

i) Terrestrial.

ii) Lacustrine (lake-bottom-deposited).

iii) Marine (ocean bottom-deposited.

Figure shows photographic of channel-Fill Sandstone

Resting on Marine Shale Red Fork, Oklahoma, USA

Figure shows fossils in Ordovician kukersite oil shale,

northern Estonia April 13, 2012 HZH 13

a) Organic matter (macerals) in oil shale Three major types of organic matter (macerals) in oil shale are

i) Telalginite,

ii) Lamalginite, and

iii) Bituminite

b) Inorganic matrix matter in oil shale Mineral matter in oil shale contains fine-grained silicate and carbonate minerals

such as calcite, dolomite, siderite, quartz, feldspar (orthoclase, albite, and anorthite),

clay minerals (illite and chlorite), marcasite, rutile, limonite, gypsum, nahcolite,

dawsonite and alum. Some oil-shale deposits also contain metals such as vanadium,

zinc, copper, and uranium among others

COMPOSITION OF OIL SHALE

Table General composition of oil shales (Altun, et al., 2006)

Inorganic matrix Bitumens Kerogens

Quartz; feldspars; clays (mainly

illite and chlorite); carbonates

(calcite and dolomite); pyrite and

others

Soluble in CS2

Insoluble in CS2;

Containing uranium, iron,

vanadium, nickel, molybdenum,

....... etc

April 13, 2012 HZH 14

COMPOSITION OF OIL SHALE

Photomicrograph showing detail of the varves in a rich Colorado oil shale specimen. The organic laminae are themselves finely laminated. The mineral laminae contain considerable organic matter, but they are readily distinguished by their coarser grain and greater thickness. Note sand grains (white). Enlarged 320 diameters.

Figure show intercalation of Organic-Rich Thin

Laminae with inorganic (minerals) laminae.

April 13, 2012 HZH 15

Largest oil shale deposits in the world are located in the Eocene Green

River Formation in Utah, Colorado, and Wyoming.

April 13, 2012 HZH 17

In-Place Resources

• Total within the Green River Formation – 1.5 to 1.8 trillion bbls

– Colorado – 1.0 trillion barrels

– Wyoming – 300 billion barrels

– Utah – 165 billion to 321 billion barrels

World conventional crude reserves – 1.3 trillion barrels

U.S. conventional crude reserves – 22 billion barrels

Saudi Arabia conventional crude reserves – 262 billion

barrels 5 18 25 35 58 69 90

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April 13, 2012 HZH 18

Recovery Methods

• Underground/surface mining and surface

retorting

Environmental concerns:

– Disturbance of land

– Use of water resources

– Greenhouse gas emissions

– Impacts on water and air quality

Room and pillar oil shale mine in Estonia

Oil Tech’s surface retort

April 13, 2012 HZH 19

Recovery Methods

• In-situ retorting – Heat shale slowly to 650 to

700 degrees F

– Recover 1/3 gas and 2/3 light oil

– In Colorado, potential for 1 acre to yield 1 million barrels of oil

Environmental concerns:

– Groundwater contamination

– Energy consumption

Advantages:

– Much less land disturbance

– No tailings

– Better recovery efficiency

– Allows access to deeper oil

shale reserves

– Higher-quality product

2006 Energy Forum20

Next Research Phase2 Step Process (at least) to Commercial

Freezewall Test• Environmental test to assure

ability to isolate ICP zone and protect adjacent water bearing zones

• Football field sized rectangular test on 15 acres near existing research

• Test robustness of freezewall barrier

• Active construction from late '05 - early '07

• Reclamation/closure 2010-12

2006 Energy Forum21

Next Research Phase

Oil Shale Test• Integrated pilot, scaleable

• BLM RD&D Lease land (160 acres)

• Land similar to commercial acreage (5120 acres)

• Active construction/site preparation '07

• 13 year life followed by reclamation/closure

Water &TemperatureMonitor Wells

FreezeWells

Heater &Producer

Wells

FracturedShaleWater

BearingZonew

SolidShale

Commercial decision near end of the decade,

… but lots of work ongoing between now and then.

2006 Energy Forum18

Mahogany Research Project

Recent research targeted key technical challenges:

• Reliable heaters

• Groundwater protection

• Economics

Results:

• Robust heaters

• 62% recovery

• Performance as modeled

• Successful freezewall testApril 13, 2012 HZH 20

White River Oil Shale Mine, Uinta Basin

April 13, 2012 HZH 21

“Back-of-the-envelope”

Underground mine:

• Assumptions: – 40 ft of 35 gpt oil shale

– 5,000 acre lease

– 50% material recovery

– 90% shale oil extraction efficiency

• Results: – 200 million bbls of oil

– 30,000 bbls per day for 20 years

In-situ methods:

• Assumptions:

– 124 ft of 25 gpt oil shale

– 5,000 acre lease

– 60% shale oil extraction efficiency

• Results:

– 700 million bbls of oil

– 95,000 bbls per day for 20 years

• Utah crude oil production =

50,000 bbls per day

• Utah petroleum consumption

= 145,000 bbls per day

• U.S. crude oil production

= 5 million bbls per day

• U.S. petroleum consumption

= 21 million bbls per day

• U.S. crude oil imports

= 10 million bbls per day

• Utah’s refinery capacity =

167,000 bbls per day

• Utah’s refinery inputs =

151,000 bbls per day

• Utah’s spare refinery capacity =

16,000 bbls per day

(2006 data)

April 13, 2012 HZH 22

In nature, crude oil deposits are occurring in two different modes, namely: i) Conventional oil reservoirs; and ii) Unconventional oil reservoirs.

Most of the world's oil reserves are recorded as unconventional oil type which oil shale is important types of this deposit in the

earth Oil shale is a fine-grained sedimentary rocks containing significant amounts of kerogen, and belonging to the group of sapropel

fuels . Oil shales can be classified by their composition (carbonate minerals such as calcite or detrital minerals such as quartz and clays)

or by their depositional environment (large lakes, shallow marine, and lagoon/small lake settings). Much of the organic matter in oil shale is of algal origin, but may also include remains of vascular land plants. Three major type of

organic matter (macerals) in oil shale are telalginite, lamalginite, and bituminite . Some oil-shale deposits also contain metals which include V, Zn, Cu, U.

Most oil shale deposits were formed during Middle Cambrian, Early and Middle Ordovician, Late Devonian, Late Jurassic, and Paleogene times through burial by sedimentary loading on top of the algal swamp deposits, resulting in conversion of the organic matter to kerogen by diagenetic processes . The largest deposits are found in the remains of large lakes such as the deposits of the Green River Formation of Wyoming and Utah, USA.

Oil-shale deposits formed in the shallow seas of continental shelves generally are much thinner than large lake basin deposits

.

Oil shale is shale that contains abundant organic matter that has not decomposed completely to produce petroleum. Oil

shales are source rocks that have not been exposed to heat or pressure long enough to convert their trapped hydrocarbons into

crude oil. Technically speaking, oil shales are not really shales and do not really contain oil, but are usually relatively hard rocks

(i.e., marls) containing a waxy substance called kerogen.

Oil can be extracted from oil shales, but they must be heated to high enough temperatures to drive the oil out. Since this process

requires a lot of energy, exploitation of oil shales is not currently cost-effective, but may become so as other sources of petroleum become

depleted.

SUMMARY and CONCLUSIONS

April 13, 2012 HZH 23

Most of the world's oil reserves are recorded as unconventional

crude oil.

Fossil fuels will continuous for ever .

April 13, 2012 HZH 24

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