mg672 oil and gas management 1

8/14/2019 MG672 Oil and Gas Management 1

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MG672 Oil and GasManagement

Global oil & gas industry

Oil and Gas formation &reserves

Origin of Petroleum

Ancient, and Less Ancient, Times

Small amounts of petroleum have been used

throughout history.

The Egyptianscoated mummiesand sealedtheir mighty Pyramidswith pitch.

The Babylonians, Assyrians, and Persiansused it to pave their streetsand hold their

wallsand buildingstogether.

Origin of Petroleum

1000 A.D. Arab scientists discovered

distillation and were able to make kerosene.

This was lost after the 12 thcentury!

Rediscovered by a Canadiangeologist called

Abraham Gesner in 1852

Origin of Petroleum

3000 BC: Fertile Crescent & Baku Seeps

Oil seeps noted along banks of Euphrates

AzerbaijanPersias land of fire

Ancient Persians and Sumatransalsobelieved petroleum hadmedicinal value.

Boatsalong the Euphrates were constructedwith woven reeds and sealed with pitch.

Origin of Petroleum

The Chinese600 BC also came across it while

digging holes for brine (salt water) and used

the petroleum for heating.

They burned the gas to evaporate brine for

salt.

The Bible even claims thatNoahused it tomake his Ark seaworthy.

American Indiansused

petroleum for paint, fuel, andmedicine.

Desert nomadsused it to treatcamels for mange, and the HolyRoman Emperor, Charles V, usedpetroleum it to treat hisgout.

Origin of Petroleum
http://en.wikipedia.org/wiki/File:Titian_-_Portrait_of_Charles_V_Seated_-_WGA22964.jpg


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1291 AD: Marco Polos Journey

Caspian oil produced for medicine, lamps

Brought back sample of oil from Sumatra

This seemed a popular idea, and up through the

19thCentury jars of petroleum were sold as

miracle tonicable to cure whatever ailed you.

People who drank this "snake oil" discovered

that petroleum doesn't taste very good!

Origin of Petroleum The Search for Oil

Yet despite its usefulness, for thousands ofyearspetroleum was very scarce.

People collected it when it bubbled to thesurface or seeped into wells.

For those digging wells to get drinking water

the petroleum was seen as a nuisance.

However, some thought the oil might have

large scale economic value.

George Bissell

George Bissell is often consideredthe father of the American oilindustry

Bissell had the innovative idea ofusing this oil to produce kerosene,then in high demand.

he and his partner, JonathanEveleth, formed the PennsylvaniaRock Oil Company for this

purpose.

After getting confirmation of the usefulness ofthe product from Yale chemist Benjamin SillimanJr., in 1854Bissell and a friend formed theunsuccessful Pennsylvania Rock Oil Company.

In 1858Bissell and a group of business menformed the Seneca Oil Company.

They hired an ex-railroad conductor namedEdwin Draketo drill for oil along a secluded

creek inTitusville Pennsylvania.

Colonel Drake

In 1856, after seeing pictures ofderrick drilling for salt, Bissell

conceived of the idea of drilling for oil,rather than mining it.

This was widely considered ludicrousat the time but on August 27, 1859,the company first succeeded in strikingoil, on a farm in Titusville,Pennsylvania.

Bissell invested heavily in thesurrounding region and ended upbecoming a wealthy business man.

The company's agent, Edwin Drake, issometimes credited with the"discovery" of oil.

Pennsylvania's "Black Gold"

Drake's well produced only thirty-five barrelsa day, however he could sell it for $20 abarrel.

News of the well quickly spread andbroughtdroves of fortune seekers.

Soon the hills were covered with prospectorstrying to decide where to dig their wells.Some used Y-shaped divining rodsto guidethem.
http://en.wikipedia.org/wiki/File:Edwindrake.jpghttp://en.wikipedia.org/wiki/File:George_Henry_Bissell_by_Gurney,_1860s.jpg


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Pennsylvania's "Black Gold"

To dig the wells six-inch wide cast iron pipeswere sunk down to the bedrock.

A screw like drillwas then used to scoop out dirtand rock from the middle.

Many discovered to their dismay that once theyhit oil they had no way to contain all of it.

Until caps were added to the wells vastquantities of oil flowed into the appropriatelynamedOil Creek.

The First Pipeline

Transporting the oil was also a problem.

In 1865 Samuel Van Syckel, an oil buyer,began construction on a two-inch widepipelinedesigned to span the distance to therailroad depot five miles away.

Theteamsters, who had previouslytransported the oil, didn't take to kindly toSyckel's plan, and they used pickaxes to breakapart the line.

Eventually Van Syckel brought in armedguards, finished the pipeline, and made aton-o-money.

By 1865wooden derricks extracted 3.5million barrels a yearout of the ground.

Such large scale production caused the price

of crude oil to plummet to ten cents a barrel.

How Much Oil?

Andrew Carnegiewas a large stockholder in

the Columbia Oil Company.

Carnegie believedthat the oil fields wouldquickly run drybecause of all the drilling.

He pe rsuaded Columbia Oil to dig a hugeholeto store100,000 barrels of oilso thatthey could make a killing when the country's

wells went dry.

Luckily there was more oil than theythought!

But don't fee l too sorry for Carnegie, hedidn't let the setback slow him down very

much, and went on to make his millions inthe steel industry.
http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=tM4auxwf0E9jJM&tbnid=U1BxxXxmWU4GvM:&ved=0CAUQjRw&url=http://rewild.info/anthropik/2007/05/the-alleghenys-black-gold/index.html&ei=gLttUrrxNfaj4APnn4CwDg&bvm=bv.55123115,d.dmg&psig=AFQjCNEzkR15cc1WmPgln9urqXDc9VNUew&ust=1383009522745809


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In contrast, "Colonel" Drakewas committed tothe oil business.

He scoured the country looking for customerswilling to buy his crude oil.

However, the bad smell, muddy black color, andhighly volatile component, called naphtha,caused few sales.

It became obvious that one would have to refinethe oil to find a market.

Early Refining

By 1860there were 15 refineriesin operation.

Known as "tea kettle" stills, they consisted of a

large iron drumand a long tubewhich acted as

a condenser.

Capacity of these stills ranged from 1 to 100

barrels a day.

A coal fireheated the drum, and three fractions

were obtained during the distil lation process.

The first component to boil off was the highly

volatile naphtha.

Next came the kerosene, or "lamp oil", andlastly came the heavy oils and tar which weresimply left in the bottom of the drum.

These early refineries produced about75%kerosene, which could be sold for high

profits.

Kerosene was so valuablebecause of a whale shortagethat had began in 1845dueto heavy hunting.

Sperm oilhad been the mainproduct of the whalingindustry and was used inlamps.

Candleswere made withanother whale product called"spermaceti".

This shortage of natural sources meant that

kerosene was in great demand.

Almost all the families across the countrystarted using kerosene to light their homes.

However, the naphtha and tar fractionswere

seen as valueless and weresimply dumpedinto Oil Creek.

Laterthese waste streams were converted

into valuable products.

In 1869 Robert Chesebrough discovered howto make petroleum jellyand called his newproduct Vaseline.

The heavy componentsbegan being used aslubricants, or as waxesincandlesandchewing gum.
http://www.google.com.cy/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=0-sknav6A09ewM&tbnid=2zshEtLg5X_MtM:&ved=0CAUQjRw&url=http://theresaromain.com/2010/12/09/r-is-for-research-lamps-lighting-and-spermaceti/&ei=F0tOUsChHYjUtQaD24GABQ&bvm=bv.53537100,d.d2k&psig=AFQjCNGBa_TD1vhlvVRBD0oUpUfaXfX2AQ&ust=1380949082741887


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Tarwas used as a roofing material. But the morevolatile componentswere still without much

value. Limited success came in using gasolineas a local

anestheticand liquid petroleum gas(LPG) in acompression cycle to make ice.

The success in refined petroleum productsgreatly spread the technique.

By 1865there were 194 refineriesin operation.

John D. Rockefeller

In 1862John D. Rockefellerfinanced hisfirstrefineryas a side investment.

He soon discovered that he liked thepetrole um industry, and devoted himself to itfull time.

As a young bookkeeperRockefeller had cometo love the order of a well organized ledger.However, he was appalled by thedisorderand instabilityof the oil industry.

Anyone could drill a well, andoverproductionplagued the e arly industry.At times this overproduction meant that thecrude oilwas cheaper than water.Rockefeller saw early on, that refining andtransportation, as opposed to production,were the keys to taking control of theindustry.

And control the industry he did!

In 1870he establishedStandard Oil, whichthen controlled 10% of the refining capacity

in the country.

Transportationoften encompassed 20% ofthe total production cost and Rockefeller

made under-the-table dealswith railroadstogive him secret shipping rebates.

This cheap transportation allowed Standard

to undercut its competitorsand Rockefellerexpanded aggressively, buying outcompetitors left and right.

Soon Standard built a network of "iron

arteries" which delivered oil across the

Eastern U.S.

This pipeline systemrelieved Standard's

dependence upon the railroads and reduced itstransportation costs even more.

By 1880Standard controlled 90% of thecountry's refining capacity.

Because of its massive size, it brought securityand stabilityto the oil business, guaranteeingcontinuous profits.

With Standard Oil, John D. Rockefellerbecamethe richest person in the World
http://www.google.com.cy/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=bi7Cx1YF6XgSlM&tbnid=2KvvLEPao-DWvM:&ved=0CAUQjRw&url=http://thepublici.blogspot.com/2010/06/to-light-one-candle.html&ei=pEtOUp-zEcKNtQafkoHoAQ&bvm=bv.53537100,d.d2k&psig=AFQjCNGBa_TD1vhlvVRBD0oUpUfaXfX2AQ&ust=1380949082741887http://www.google.com.cy/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=bi7Cx1YF6XgSlM&tbnid=2KvvLEPao-DWvM:&ved=0CAUQjRw&url=http://thepublici.blogspot.com/2010/06/to-light-one-candle.html&ei=pEtOUp-zEcKNtQafkoHoAQ&bvm=bv.53537100,d.d2k&psig=AFQjCNGBa_TD1vhlvVRBD0oUpUfaXfX2AQ&ust=1380949082741887


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Origin of petroleum

The great compositional complexity of

petroleums (this term includes both oil and

gas) reflects the combined effects of allprocesses involved in the origin of petroleum

accumulations and their fate during long

periods of geological time.

Since relevant geological and geochemical

conditions under which these processes

proceed can vary from place to place, thecomposition of petroleums are subject to

great variations.

As a general rule, the origin of petroleum is

neve r in the reservoir accumulation from

which it is produced.

Instead, petroleums have e xperienced a long

series of processes prior to accumulation in

the reservoir.

Fig. 1. Main geological conditions and geochemical processes requiredfor the formation of petroleum accumulations in sedimentary basins:

1) petroleum generation in source rocks;2) primary migration of petroleum;3) secondary migration of petroleum;4) accumulation of petroleum in a reservoir trap;

5) se epage of petroleum at the Earths surface as a consequence of afractured cap rock.

Petroleum accumulation forms in sedimentary

basins and can be discovered by exploration, if

the following geological conditions are met:

Occurrence of source rocks which generatepetroleums under proper subsurface

temperature conditions.

Sediment compaction leading to expulsion of

petroleum from the source and into the

reservoir rocks (primary migration).


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Occurrence of reservoir rocks of sufficient

porosity and permeability allowing flow of

petroleum through the pore system(secondary migration).

Structural configurations of sedimentarystrata whereby the reservoir rocks form

traps, i.e. closed containers in the subsurface

for the accumulation of petroleum.

Traps are sealed above by impermeable

sediment layers (cap rocks) in order to keep

petroleum accumulations in place.

Correct timing with respect to the sequence bywhich the processes of petroleum generation

/migration and trap formation have occurredduring the history of a sedimentary basin.

Favourable conditions for the preservation ofpetroleum accumulation during extendedperiods of geologic time, i.e. absence ofdestructive, such as the fracturing of cap rocksleading to dissipation of petroleumaccumulations, or severe heating resulting in thecracking of oil into gas.

The question of the origin of petroleum hasbeen hotly debated for a long time.

A great many theories, hypotheses andspeculations have been proposed.

Decades ago, various ideas on a possibleinorganic origin of petroleum were broughtforward, e .g. that it results from the reactionof iron carbide with water deep in the Earthscrust.

The main evide nce supporting these theories

was the occasional occurrence of

hydrocarbon fluid inclusions and solidbitumens in igneous rocks as well as a few

cases of oil and gas fields hosted in fractured

basement rocks (e.g. granites, basalts, and

metamorphic rocks).

However, in most of these cases it could be

demonstrated that the petroleum materials wereultimately generated in sedimentary rocks and hadbeen transported, e.g. by convective flow ofmineralising aqueous fluids, into the granites, or thatthe y had migrated from sedimentary strata over longdistances to accumulate in fractured basement rocks.

These cases of petroleums occurring in basementrocks are extremely rare and not commerciallyimportant when compared to the vast majority ofhydrocarbon reserves in sedimentary basins (Selley,1998).

One of the main arguments concerns the

ubiquitous occurrence of biological markermolecules in petroleums, such as porphyrines,steranes and hopanes.

The highly specific carbon structures of thesemolecules could not be synthesized by inorganicreactions.

They are clearly and uniquely derived frommolecular structures synthesized by livingorganisms.


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Today, the evidence in favour of an organic origin ofpetroleum is overwhelming.

One of the main arguments concerns the ubiquitousoccurrence of biological marker molecules inpetroleums, such as porphyrines, steranes andhopanes.

The highly specific carbon structures of thesemolecules could not be synthesized by inorganicreactions.

They are clearly and uniquely derived from molecularstructures synthesized by living organisms.

Petroleum source rocks

Petroleum source beds are fine grained, clay-

rich siliclastic rocks (mudstones, shales) or

dark coloured carbonate rocks (limestones,marlstones), which have generated and

effectively expelled hydrocarbons.

A petrole um source is characterised by three

essential conditions:

1. it must have a sufficient content of finelydispersed organic matter of biological origin;this organic matter must be of a specificcomposition, i.e. hydrogen-rich;

2. the source rock must be buried at certaindepths and

3. subjected to proper subsurface temperatures inorder to initiate the process of petroleumgeneration by the thermal degradation of

kerogen.

Based on e mpirical evidence, minimumconcentration levels of 1.5% and 0.5% totalorganic carbon (TOC) in source rocks ofsiliclastic and carbonate lithologiesrespectively have been established (Hunt,1996).

The organic carbon concentration is anapproximate measure of the organic matter

content of a rock.

Organic matter is predominantly composed of organic

carbon, but also contains minor amounts of hetero-elements (N, S, and O).

This minimum concentration of organic carbon insource rocks is controlled by the relationship betweenthe quantity of petroleum generated and the internalstorage capacity of the rocks in terms of theirporosity.

If too l itt le organic matter is present, the smallquantities of petroleum generated will not exceed thestorage capacity of the rock, i.e. no petroleumexpulsion will take place.

Most source rocks which have effectively generated

and expelled commercial quantities of petroleumhave TOC concentrations in the order of 2-10%.

An example of a prolific source rock of siliclasticlithology is the Upper Jurassic Kimmeridge ClayFormation in the North Sea Basin which has generatedmost of the oil accumulated in many large fields inthat area.

It has TOC contents ranging mostly between 5 and12% (Bordenave et al., 1993).


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A good-quality petroleum source rock of carbonatelithology is exemplified by the Triassic-age MerideLimestone, which is the source of the oil present in

several fields in the Po valley area of northern Italy. Its TOC content varies mostly between 0.5 and 1.5%

(Leythaeuser et al., 1995).

The reason why petroleum source rocks of carbonatelithologies tend to have significantly lower TOCconcentrations has to do with the quality andcomposition of the organic matter present.

In carbonate source rocks, the organic matter tends tobe richer in hydrogen.

Most petroleum source rocks display dark

brown to black colours. This is due to the

presence of finely disseminated organicmatter as well as finely dispersed pyrite

crystals (FeS2).

2 cm section seen

under a microscope

Basic Depositional Scenarios

There are three basic depositional scenarios

which ensure favourable conditions for the

prese rvation of organic matter.

1. The stagnation model requires a silled basin,

i.e. a marine basin which has highly

restricted water c irculation with the open

ocean (Fig. 3 A).

The Stagnation Model

This is the case today, e.g. of the Black Sea which is upto 2 ,500 m deep but only has a narrow 25 m deep

connection to the Mediterranean Sea. Due to the high input of freshwater from rivers, surface

waters of the Black Sea have lower salinity levels.

Below the halocline lies a huge, stagnant

water mass which provides favourable

conditions for the preservation of deadbodies of algae that settle down from the

surface interval where there are light and

nutrients for their growth (bioproductivity).

Productivity Model

The second principal depositional system in

this context is the so-called productivity

model (Fig. 3 B).


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Wherever they encounter major topographicelevations they displace nutrient-rich bottom

water masses towards the surface of theocean.

In this way, a series of processes and effectsare initiated which are similar to those in theupwelling regime leading to theestablishment of an open-ocean oxygen-minimum zone.

Wherever this oxygen minimum zone

impinges on a continental shelf, organic

matter-rich sediments are deposited.

Such conditions can be observed in todays

oceans, e.g. along parts of the deep shelf

offshore India and Pakistan.

What has been described here in terms oftype of organic matter input for marinesediment systems applies in a similar way togreat lakes on the continents, e.g. the lakes inthe East African Rift Valley.

Biomass derived from freshwater algae andbacteria is deposited in dysaerobic oranaerobic bottom waters of deep lakes, the

water masses of which never get overturned.

All the depositional environments of marine andfreshwater systems can also receive an input oforganic matter derived from higher land plantstransported by rivers or glaciers, or wind-blown.

In contrast to algal or bacterial biomass which isrich in hydrogen, land plant-derived organicmatter tends, due to high contributions bycellulose and lignin-derived precursor materials,

to be rich in oxygen.

Kerogen

The solid organic matter in source rocks which

is insoluble in low-boiling organic solvents is

called kerogen.

Kerogen is partly formed by the accumulation

of resistant macromolecular substances of

biological origin such as cellular lipids, algae

cell walls, membranes, cuticles, spores and

pollen, etc.

Diagenesis

Other parts of kerogen are formed in sedimentsduring a process called diagenesis: The geochemical and mineralogical processes that

occur within the topmost interv al of a sedimentarycolumn.

Organic matter is synthesized by living organisms inthe form of biopolymers such as carbohydrates,proteins, lignin, etc.

Kerogen is, however, not a polymer in a strictchemical sense, rather a complex mixture ofhigh molecular weight substances.


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The main building blocks are polycondensed

aromatic ring-systems with attached aliphatic

side chains of various lengths which areinterconnected by a variety of functional groups,

such as esther, ketone and sulphide-bridges. In

summary, kerogen consists of a physical mixture

of diagenetically restructured biomass as well as

preserved biosynthesized compounds (Killops

and Killops, 1993).

A useful and initial geochemical approach fordetermining the complex composition ofkerogen is by elemental analysis andconsideration of the relationship between theatomic hydrogen/carbonratio H/C and theatomic oxygen/carbon-ratio O/C (F ig. 4).

The high H/C-ratio of type I-kerogens, goes backto a high input of algae and bacterial biomass

and

van Krevelen diagram

Evolutionary pathways

In this way, thegreat varietyof kerogensoccurring innature can beclassified intothree broadcategoriesreferred to astype I-, type II-and type III-

kerogens.

Fig. 4. Variation of elemental composition of naturallyoccurring kerogens in terms of their atomic H/C- and O/C-ratios

Classification of kerogens into three broad categories.

Elemental composition of organic matter in freshlydeposited sediments is plotted towards the upper rightend of each field (diagenesis stage).

With increasing burial, kerogen transformation proceedsduring the catagenesis and metagenesis stages.

Fig. 5. Diagram to

illustrate the main

conditions andproce sses for

kerogen formation

from biological

precursor materials

and kerogen

transformation into

petroleum products

with increasing

maturation


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Petroleum generation

Oil and gas are generated by the thermal

degradation of ke rogen in the source beds.

With increasing burial, the temperature inthese rocks rises and, above a certain

threshold temperature, the chemically labile

portion of the kerogen be gins to transform

into petroleum compounds.

The main reaction mechanism is the breaking

of carbon-carbon bonds (cracking), which

requires that the input of thermal energyexceed certain minimum levels (activation

energy).

Activation energies vary according to the

position and type of carbon-carbon bond

within the kerogen structure.

At higher temperature levels, petroleum

compounds are generated by the cracking of

carbon-carbon bonds within the kerogenstructure in such a way that long aliphatic

side chains and saturated ring structures are

removed from it.

These reactions result in gradual changes in

the elemental composition of the kerogen,

especially in a decrease of its hydrogencontent.

These changes are expressed in the van

Kre velen diagram for each kerogen type as

trend lines, the so-called evolutionary

pathways (see again Fig. 4).

The generation of oil and gas in source rocks

is a natural consequence of the increase of

subsurface temperature during geologic time.

The process of kerogen transformation with

increasing temperatures is called maturation,

which is subdivided into the catagenenis and

metagenesis stages

With respect to the stage to which petroleum

generation has advanced, the organic matter

is labeled immature prior to the onset ofhydrocarbon generation, mature if

hydrocarbon generation is in progress, or

over mature when these reactions have been

terminated.


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Heat is the main driving force in maturation

and petroleum generation reactions.

oil window

The temperature interval where oil

generation is in progress is referred to as the

liquid window or oil window.

It extends over the temperature interval of

about 80-150C.

B. Formation of Oil

Diagenesis

Surface to about km, T , 50C; CH4

Catagenesis

50 to 150C, P about 1.5 kb

Compaction of sediment, expulsion of water

Organic matter becomes kerogen and liquidpetroleumbiogenic gas decreases, howeversome formed by thermal crackingof kerogen

Wet gas: methane+ethane+propane+butane

B. Formation of Oil

Metagenesis

Greater than 4 km, and 150C

Dry gas

C rich residue

Graphite developed

Origin (1): Chemistry

Crude Oil

Hydrocarbon

en.wikipedia.org/wiki/Image:Octane_molecule_3D_model.pngen.wikipedia.org/wiki/Image:Petroleum.JPG

Oil and gas are made of a mixture of

different hydrocarbons.

As the name suggests these are large

molecules made up of hydrogenatoms

attached to a backbone of carbon.

Origin (2): Planktoncache.eb.com/eb/i mage?id=93510

en.wikipedia.org/wiki/Image:Copepod.en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg

Most oil and gas starts life as microscopic plants and animals

that live in the ocean.

Plant plankton Animal plankton

10,0

00ofthesebugs

wouldfitonapinhead!


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Origin (3): Bloomsserc.carleton.edu/images/ microbelife/topics/red_tide_genera.v3.jpg

Today, mo st pl ankton can be

found where deep ocean

currents rise to the surface

This upwelli ng water is rich in

nutrients and causes the

plankton to bloom

Blooms of certain plankton

called dinoflagellatesmay

give the water a red tinge

MiriamG odfrey

Dinoflagellate bloom

Origin (4): On the sea bedupload.wikimedia.org/wikipedia/ en/0/04/Plankton.jpg

When the plankton dies it rains

down on sea bed to form an

organic mu sh

Sea bed

en.wikipedia.org/wiki/Image:Nerr0328.jpg

If there are any animals on the

sea bed these will feed on the

organic particles

Origin (5): Black Shaleupload.wikimedia.org/wikipedia/ en/0/04/Plankton.jpg

However, i f there is li ttle or no

oxygen in the water then animals

cant survive and the organic

mush accumulates

Where sediment contains

more than 5% organic matter,

it eventually forms a rock

known as aBlack Shale

Earth Science W orld Image Bank

Origin (6): Cooking

www.oilandgasgeology.com/oil_gas_window.jpg

As Black Shale is buried, it is h eated.

Kerogen

Gas

Oil

Organic matter is first changed by the

increase in temperature into kerogen,

which is a solidform of hydrocarbon

Around 90C, it is changed into a liquid

state, which we call oil

Around 150C, it is changed into a gas

A rock that has produced oil and gas in

this way is known as a Source Rock

Origin (7): Migration

www.diveco.co.nz/ img/gallery/2006/diver_bubbles.jpg Hot oil and gas is less dense than

the source rock in which it occurs

Oil and gas migrate upwards up

through the rock in much the same

way that the air bubbles of an

underwater diver rise to the surface

The rising oil and gas eventually gets

trapped in pockets in the rock called

reservoirs

Rising oil

Origin (8): Ancient EarthRon Blakey, Arizona Flagstaff

During mid-Mesozoic times

around 150 million years ago,

conditions were just right

to build up huge thicknesses

of Black Shale source rocks

Ancient Earth

The worlds main oil deposits all formed in warm shallow seas

where plankton bloomed but bottom waters were deoxygenated


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Why is there oil in Texas? II. A Strategic Natural Resource

National Geographic, 2002

Origin (9): Source of North Sea Oil

Ancient Earth

Ian and Tonya West

The Kimmeridge Clay is a Black Shale with u p to 50% organic

matter. I t is th e main sou rce rock for the N orth Sea Oil & Gas

Province

Black Shale

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