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MKPP 1213
APPLIED GEOSCIENCE &GEOPHYSICS
LECTURER: PROF. DR. RADZUAN JUNIN
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MKPP 1213
CHAPTER 1
INTRODUCTION
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Introduction
What isApplied Geoscience & Geophysics orPetroleum Geoscience?
The disciplines of geology and geophysicsapplied to understanding the originand
distribution, andpropertiesof petroleum and
petroleum-bearing rocks.
Theimportanceof petroleum geoscience is tofind petroleum (petroleum province) andhelp
produce it.
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Basic Geological Principles
To become a petroleum province, fiveingredientsor elements are involved;
the source,Seal (cap rock),
reservoir, and overburden rock
trap formation, and
timing of petroleum migration (Generationmigrationaccumulation of hydrocarbons).
These elements Petro leum system
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Basic Geological Principles
A petroleum system contains a pod of active
source rockand all genetically related oil and
gas accumulations. It includes all the geologic elements and
processesthat are essential if an oil and gas
accumulation is to exist.
Practical application of petroleum systems can
be used in exploration, resource evaluation, and
research.
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Basic Geological Principles
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(Foreland Basin Example)
Overburden Rock
Seal Rock
Reservoir Rock
Source Rock
Underburden Rock
Basement Rock
Top Oil Window
Top Gas Window
Geographic Extent of Petroleum System
Petroleum Reservoir (O)
Fold-and-Thrust Belt
(arrows indicate relative fault motion)
Essential
Elements
of
Petroleum
System
O O
Sedimentary
B
asinFill
OStratigraphic
Extent ofPetroleum
System
Pod of Active
Source Rock
Extent of Prospect/FieldExtent of Play
Cross Section Of A Petroleum System
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Basic Geological Principles
The source:
Asource rock is a
sedimentary rock thatcontains sufficient
organic matter, when it is
buried and heated it will
produce petroleum. Good examples: shale
and claystone/mudstone.
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Basic Geological Principles
High concentrations of organic matter tend to
occur insedimentsthat accumulate in areas
of high organic matter productivity and
stagnant water. To preserveorganic matter, the oxygen
contents of the bottom waters and interstitial
waters of the sediment need to be very low
or zero, and a rapid sedimentation rate.
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Basic Geological Principles
The Seal:
Seals tend to be fine-grained
or crystalline, low-permeability
rocks. Typical examples
include mudstone/shale,
cemented limestones, cherts,
anhydrite, and salt (halite).
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Basic Geological Principles
Seals to fluid flow can also develop along fault
planes, faulted zones, andfractures.
The presence of a seal or seals is critical forthe development of accumulations of
petroleum in the subsurface.
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Basic Geological Principles
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Basic Geological Principles
The Trap:
The geometryof the sealed petroleum-bearing
container.
The simplest trapping configurations are domes(four-way dip-closed anticlines) and faultblocks.
The mapping and remapping of trap geometry is
a fundamental part of petroleum geoscience.
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Basic Geological Principles
The Reservoir:
The rock plus void space
contained in a trap.
The petroleumtogether withsome wateroccurs in the pore
spaces between the grains (or
crystals) in the rock.
Reservoir rocks are most
commonly coarse-grained
sandstonesor carbonates..
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Basic Geological Principles
Porous rock and porosity:
Porosityis the void spacein the rock, reported
either as a fractionof one or as a percentage.
Most reservoirs contain >0% to
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Basic Geological Principles
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Basic Geological Principles
The timing of petroleum migration:
The timing of petroleum migration relative to the
time of deposition of the reservoir/seal
combinations and the creation of structure withinthe basin.
In order to determine whether the reservoir,
seal, and trap are available to arrest migrating
petroleum, it is necessary to reconstruct the
geologic historyof the area under investigation.
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Petroleum Systems
Petroleum System Investigation:
Identifies,
names,
determines the level of certainty, and
maps the geographic, stratigraphic, and
temporal extent of a petroleum system.
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Petroleum Systems
To identifya petroleum system, the
explorationist must find some petroleum.
Any quantity of petroleum, is proof of a
petroleum system. An oil or gas seep, a show of oil or gas in a
well, or an oil or gas accumulation
demonstrates the presence of a petroleum
system.
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Petroleum Systems
The nameof a petroleum system contains
several parts that name the hydrocarbon fluid
system:
1. The source rock in the pod of active sourcerock
2. The name of the reservoir rock that contains
the largest volume of in-place petroleum
3. The symbol expressing the level of certainty.
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Petroleum Systems
A petroleum system has three important
temporal aspects:
1.Age- the time required for the process of
generation
migration
accumulation of hydrocarbons 2. Critical moment - the time that best depicts the
generationmigrationaccumulation of hydrocarbons in
a petroleum system.
3. Preservation time - begins immediately after thegenerationmigrationaccumulation process occurs
and extends to the present day.
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Prudhoe Bay: Event Timing Favors
Accumulation of Shublik Oil and Gas
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Timing of formation of the major elements of apetroleum system, Maracaibo basin, Venezuela.
From Schlumberger Oilfield Glossary
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Basic Geological Principles
Timescales: Petroleum maturation, migrationand trappingof
oil can occur in a few million years.
Geologic timeis divided, using a hierarchicalscheme, into a variety of named units.
The basic unit in this scheme is the period.
The sequence of periods with their attendant
subdivisions and supra-divisions makes up thestratigraphic column.
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The Geologic Timescale
The geologic timescale - a calendar of Earthhistory.
The largest defined unit of time shown on thegeologic timescale is the supereon, composed
of eons. Eon - the greatest expanse of time.
The earliest is the Hadean (beneath the Earth)Eon, ranging from 4.6 to 3.8 billion yrs ago.
The earliest-known life forms appear in rock fromtheArchean (ancient) Eon, about 3.8 to 2.5billion yrs ago.
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The Geologic Timescale
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Generalized Stratigraphy of Malay Basin
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The Geologic Timescale
TheArchean Eon gave way to the Proterozoic(early life) Eon (2,500-543 mya).
The beginning of the Phanerozoic (visible life)Eon, 543 mil years ago, marks the first point at
which we find abundant fossil evidence. Phanerozoic subdivided into threeeras: the
Paleozoic (543-252 mya) , Mesozoic (252-65mya) , and Cenozoic (65 mya-present day) .
The first part of the Paleozoic (ancient life) Erawas dominated by marine invertebrates, suchas corals, clams, trilobites, and later fish andamphibians.
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The Geologic Timescale
TheMesozoic (middle life) Era was dominatedby marines and terrestrial reptiles, including thedinosaurs.
TheCenozoic (recent life) Era, which continues
today, is distinguished by its rich variety ofmammals.
Eras are subdivided intoperiods.
Periods are subdivided intoepochs.
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Plate Tectonic Context of
Petroleum Basins
Basinsare generated by plate tectonics, the
process responsible for continental drift.
The Earth's crust is made up of about 20 rigid
plates.
Plates may be stretched and broken or pushed
together, or may rotate past each other. Each of
these processes
divergence(extension),convergence(compression), and strike-slip(or
wrench)can lead to the formation of basins.
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Continental Drift
The idea that continents,particularly South America and
Africa, fit together like pieces ofa jigsaw puzzle.
However, little significance wasgiven this idea untilAlfredWegener(1915) proposed acontroversial hypothesis ofcontinental drift.
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Continental Drift
Wegener suggested that thecontinents floaton a denserunderlying interior andperiodicallybreak up and drift
apart. Today the concepts of seafloor
spreadingand plate tectonicsare firmly established.
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Plate Tectonic Context of
Petroleum Basins
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Seafloor Spreading
The rates of spreading(frommid-ocean ridges) on either siderange from 1 to 6 cm/year ortotal rate from 2 to 12cm/year.
At this rate it would have takenabout 200 millionyears for thepresent Atlantic Ocean to attainits present width.
An interesting feature about themid-ocean spreading ridges isthat they are sites for bothvolcanic and earthquakeactivities.
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Plate Tectonics
In the 1960s, an exciting new hypothesiscalled plate tectonicsrevolutionized ourunderstanding on how the outer portion ofthe Earth functions.
According to this theory, the uppermostmantle, along with the overlying crust,behave as a strong, rigid layer, known asthe lithosphere, which is broken intopieces called plates and their movementasplate tectonics.
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Plate Tectonics
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Plate Tectonics Context of
Petroleum Basins
The lithosphere(rigid plate) overlies a weakerregion in the mantle known as theasthenosphere.
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Plate Tectonic Context of
Petroleum Basins
Plate Boundaries: there are three basic typesof plate boundaries or margins.
Divergentplate boundaries
Convergentplate boundaries
Transformplate boundaries
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Plate Tectonics
Where two plates converge, they produce anarrow, deep depressionas the subductingplate bends downward into the mantle. Suchdepressions are calledoceanic trenches.
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