BasinGeologyAnOverView_TitoPerdana.pdf

7/30/2019 BasinGeologyAnOverView_TitoPerdana.pdf

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Basic Geology: An Overview

Tito Satria Putra Perdana

DCS Borehole Geologist

Schlumberger


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2008 Schlumberger. All rights reserved.

An asterisk is used throughout this presentation to denote a mark of Schlumberger.Other company, product, and service names are the properties of their respective owners.

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Outlines

What is Geology?

What are Rocks?: Igneous, Sedimentary, Metamorphic

Processes in Geology: Exogenic, Endogenic

Petroleum System

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What is Geology ?

Geology (from Greek, geo earth and logos study): is the science

that comprises the study of the solid earth and the processes by

which it is shaped and changed.

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What is Geology 2?

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What is Rock - Definition

Rock: simply a mixture of minerals where the composition may vary

in containment minerals.

Mineral: naturally occurring, inorganic substance, characterized byan exact crystal structure. Chemical structure can be exact or

varying.

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What is rock 2 - Mineral

How do we classify minerals?

Crystal structure (Hexagonal, Trigonal, etc)

Chemical composition (Silicates, Oxide, Sulfide, etc) Physics (Hardness, Specific gravity, Color, Luster,

Streak, Cleavage)

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What is rock-3 - Mineral

Example of minerals:

Quartz (SiO2): silica mineral, trigonal crystal, hardness 7 (Mohs

Scale), luster vitreous to waxy.

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What is rock 4 - Mineral

Example of minerals:

Calcite (CaCO3): carbonate mineral, trigonal crystal, hardness 3

(Mohs Scale), luster vitreous to pearly.

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What is rock 5 Rock Type

Types of rock:

Igneous rock

Sedimentary rockMetamorphic rock

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What is rock 6 Igneous Rock

Igneous Rock:

formed through cooling and solidification of magma or lava.

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What is rock 6 Igneous Rock

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What is rock 7 Mineral in Igneous Rock

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1400C

800C


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What is rock 8 Igneous Rock Type

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What is rock 9 Sedimentary Rock

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The origin of sedimentary rocks

A sedimentary rock has a long historyand has been

subjected to modification by various processes

4 basic processes:

Weathering

Transport

DepositionCompaction and

cementation


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What is rock 10 Sedimentary Rock Type

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Siliciclastics:

Weathering productTransported

Derived from the land

Chemical rocks:

Evaporation,precipitation

Biochemical rocks:

Plants or animals

skeletons making

sediments


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What is Rock 11 - Siliciclastic Rocks

Made by the accumulation of particle of older rock (clasts or mineral grains)

deposited in basin area.

Classified mainly by its grain size

Conglomerate /

Breccia

Sandstone

Siltstone

Claystone

Wentworth scale

17AT UI Student Chapter


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What is Rock 12 - Siliciclatic Rock

Texture

Grain size

Grain Shape

Sorting

Grain Orientation

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What is rock 13 Chemical Rock

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Chemical Deposited from aqueous solution

and precipitation by chemical

process.

No energy or current dependent.

Evaporation process (Gypsum,Halite)

stalagmit

e

stalactit

e

Salt

lake


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What is Rock 14 Biochemical Rock

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Biochemical Rocks Form from biological

process.

Their shell and skeletal are

rich of Ca, Mg, Si.

Carbonate rock (CaCO3),

Coal


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What is Rock 15 - Metamorphic Rocks

From existing igneous or sedimentary rocks

Mineral and textural change under high pressure and high temperatures

More complex as it deals with heat, pressure which lead to physics and chemical

change

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What is Rock 16 Metamorphic Rock Classification

Foliated

Complex composition

Foliation (banding, slaty, schistosity

etc)

Gneiss, Schist, Slate (parent rock

is shale)

Non Foliated

Few mineral

Granular, No mineral orientation

Quartz Quartzite, Limestone

Marble, CoalAnthracite Coal

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Geological Processes Rock Cycle

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Geological Processes Exogenic Processes

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Geological Processes endogenic Plate Tectonic

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G l i l P F ldi


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Anticline

SynclineOldest rock

Youngest

rock

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Geological Processes - Folding

G l i l P F ldi


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Geological Processes - Folding

G l i l P F lti


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Geological Process - Faulting

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G l i l P F lti


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Example Kabab Canyon, Utah

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Geological Processes - Faulting

G l i l P F lti


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Oil or Gas

WaterFault

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Geological Processes - Faulting

Structural Hydrocarbon Traps


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Oil / WaterContact

Gas

Fold (Anticlinal) Trap

Oil/GasContact

Oil

Closure

Oil

SaltDiapir

Seal

Structural Hydrocarbon Traps

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Big Picture of Petroleum System


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Petroleum system consists of:

Mature source rock

Presense of organic matter

Sufficient temperature and pressure

E.g: Shale

Migration path

Typically from a structurally low are to a higher are due to HC relative bouyancy

Reservoir rock

Body of rock with adequate porosity to store the fluids and permeability to transmit the fluids.

E.g: Sandstone, Limestone

Seal

Simply an impermeable rock that act as barrier to further migration of HC liquids

Shale, Evaporite sedimentary rock ( Halite, gypsum)

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Trap A configuration of rocks suitable for containing HC and sealed by the cap rock in which HC will not migrate

Structural traps (fault, fold), Stratigraphic Trap (Pinch out, unconformities, reef build ups, etc)

Timing

Appropriate relative timing of formation and the process of HC generation, migration, and accumulation are importantfor HC to accumulate and preserved.

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Cross section of Petroleum System


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Cross section of Petroleum System

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