Module 3 Final - HYDROCARBON AND RESERVOIR GEOLOGY

8/7/2019 Module 3 Final - HYDROCARBON AND RESERVOIR GEOLOGY

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Hydrocarbon and Reservoir Geology

MODULE 3

HYDROCARBON AND RESERVOIR GEOLOGY

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MODULE 3

HYDROCARBONS AND RESERVOIR GEOLOGY

TABLE OF CONTENTS

Page

Preliminary Pages 3-i to v

SECTION 1 INTRODUCTION TO PETROLEUM 3-1-1

1.1 DEFINITION OF PETROLEUM 3-1-3

1.2 THE OIL AND GAS INDUSTRY 3-1-3

EXERCISES RELATING TO SECTION 1 3-1-5

SECTION 2 BASIC GEOLOGY 3-2-1

2.1 TYPES OF ROCK 3-2-3

2.1.1 General 3-2-3

2.1.2 Igneous Rock 3-2-3

2.1.3 Sedimentary Rock 3-2-3

2.1.4 Metamorphic Rock 3-2-5

2.1.5 The Cycle of Rocks 3-2-52.2 ROCK STRUCTURE 3-2-5

2.2.1 General 3-2-5

2.2.2 Folds 3-2-7

2.2.3 Faults 3-2-7



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TABLE OF CONTENTS

Page

SECTION 3 ORIGINS OF HYDROCARBON DEPOSITS 3-3-1


SECTION 4 SEDIMENTARY ROCK 3-4-1

4.1 GENERAL 3-4-3

4.2 POROSITY AND PERMEABILITY 3-4-34.2.1 General 3-4-3

4.2.2 Porosity 3-4-3

4.2.3 Permeability 3-4-3

4.2.4 Cementation 3-4-4

4.3 TYPES OF SEDIMENTARY ROCK 3-4-4

4.3.1 General 3-4-4

4.3.2 Sandstone 3-4-54.3.3 Shale 3-4-5

4.3.4 Limestone 3-4-5

4.3.5 Evaporites 3-4-5


SECTION 5 RESERVOIR FORMATION 3-5-1



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TABLE OF CONTENTS

Page

SECTION 6 EXPLORATION 3-6-1

6.1 EXPLORATION METHODS 3-6-3

6.2 DRILLING PROPOSAL 3-6-3



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TABLE OF CONTENTS

ILLUSTRATIONS

FIGURE NO. DESCRIPTION

1-1 Global Energy Supply

2-1 Sediment Formation

2-2 Cycle of Rocks

2-3 Types of Fold

2-4 Typical Fault

5-1 Oil Seeps

5-2 Anticlinal Trap

5-3 Migration of Petroleum

5-4 Salt Dome Formation

6-1 Seismic Surveying


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SECTION 1

INTRODUCTION TO PETROLEUM

PRODUCTION OPERATIONS COURSE

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Figure 1-1 Global Energy Supply


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1 INTRODUCTION TO PETROLEUM

1.1 DEFINITION OF PETROLEUM

The word petroleum comes from the Greek/Latin words petra, meaning rock,

and oleium, meaning oil. Rock oil, or crude oil, is an oily flammable liquid,

varying from almost colourless to black. It comprises a complex mixture of

hydrocarbons (i.e. basically chemically organic material) with small quantities

of other materials, existing at many places in the upper strata of the earth.

It can vary from black, tarry asphalts to light oils which can be used almost

directly as motor fuel. In between are oils of all colours varying through red,

reddish brown, dark brown to black, and some fluorescent green or purple in

reflected light. In odour some smell sweet, some smell like turpentine, and

others have an odour like rotten eggs due to the presence of sulphur

compounds. Wax occurs in some oils; others have none.

In addition to liquid hydrocarbons, large quantities of hydrocarbon gas are

usually present in the wellhead product, often exceeding the liquid content.

1.2 THE OIL AND GAS INDUSTRY

Refer to Figure 1-1.

Petroleum has been used for thousands of years. Seepages from cracks in

the ground were collected and used for lamp fuel and medicine in the Middle

East and China over 3000 years ago. Dried out oil seeps, in the form of

bitumen lakes, have for centuries provided material to keep ships watertight,

build roads and even as mortar for house building (by the ancient Greeks).

The petroleum industry as it is known today began in the USA. The first well

to be drilled for oil was in 1859, the oil produced being used to make kerosene

for oil lamps.

The invention of the gasoline engine, around 1900, increased the demand for

oil. Kerosene had to be refined to produce the lighter grade of petroleum

(gasoline) needed for automobile fuel. This requirement generated the growth

of the refinery industry. Demand further increased when ships changed from


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coal to oil for fuel. Since those days, the uses for oil and gas have steadily

increased.

The petrochemical industry uses petroleum to produce many products such

as soap, detergents, cosmetics, perfumes, plastics and medicines. Many newproducts have been developed by the industry to improve living standards.

Today the economy of the world depends upon the petroleum industry.

More recently, governments and industry have come to appreciate that

petroleum is a scarce and valuable resource. They have adopted

conservation policies designed to prevent waste.

In the past, produced gas was flared as there was no means to harness or

use it for fuel. Today, gas is transported along pipelines for industrial and

domestic distribution and consumption. It may also be liquefied for shipment

to distant users. If there is no immediate requirement for gas, it may be

reinjected into the reservoir to provide gas lift or simply as a means of

conserving it for future use.

Over the years the world demand for petroleum has increased considerably.

This demand will continue to increase as more nations become industrialized.

The following figures illustrate this growth:

1900 100 million (100 000 000) barrels per year

1981 20 billion (20 000 000 000) barrels per year

1990 80 billion (80 000 000 000) barrels per year.

These figures only account for liquid oil products. Liquefied gas levels also

show increases as more gas becomes available. Liquefied Natural Gas

(LNG) is being used in more and more domestic and industrial applications.

For these reasons, exploration and prospecting for new hydrocarbon fields is

an ongoing and ever important aspect of the oil and gas industry. To

appreciate how this is carried out, some understanding of the geology

involved is essential and is covered in this training module.

This module also provides information which will help in the understanding of


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the composition, characteristics and behaviour of wellhead fluids.


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EXERCISES RELATING TO SECTION 1

1 Crude oil can appear at the wellhead in various colours. List 4 of them.

2 What causes crude oil to smell like rotten eggs?

3 Name 3 historical uses for bitumen.

4 In which country did the modern petroleum industry begin?

5 Name 4 products derived from petroleum produced by the petrochemical

industry.

6 Produced gas is sold for domestic and industrial use. Name 1 other use.

7 What was the approximate worldwide demand

for petroleum in 1990 (in barrels per year)?

(a) 10 million

(b) 20 billion

(c) 80 billion

(d) 120 billion


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SECTION 2

BASIC GEOLOGY


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Figure 2-1 Sediment Formation


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2 BASIC GEOLOGY

2.1 TYPES OF ROCK


2.1.1 General

All the rocks of the Earth can be divided into three basic types:

igneous

sedimentary

metamorphic.

Of these three, it is sedimentary rock which is of particular interest

to the petroleum geologist as this is where hydrocarbons are

formed and trapped.

2.1.2 Igneous Rock

In the centre of the Earth is a hot molten mass of rock known as

magma. Magma is released at the surface when volcanoes erupt.

The released molten rock quickly cools and solidifies into igneous

rock. Magma can also cool and solidify without breaking out onto

the surface.

2.1.3 Sedimentary Rock

The forces of nature in the form of wind, rain, temperature changes,

tides and gravity begin to attack igneous rock as soon as it has

cooled. Over millions of years, this erosion process is considerable

and is extreme enough to wear away whole mountain ranges given

sufficiently long time scales. The eroded rock does not, however,

simply lay on the surface but is carried away by the action of wind,

rain and river flow, eventually to be deposited in the sea. The

layers thus deposited are known as sediments.


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K I O - 4 - 0 1 5 8 . C D R

M E T A M O R P H I C

R O C K S

M A G M A

S E D I M E N T A R Y

R O C K SS E D I M E N T S

I G N E O U

R O C K S

P R E S S U R E

C E M E N T A T I O N

E R O S I O N

H E A TC O O L I N G

Figure 2-2 Cycle of Rocks


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As these sediment layers build up, the overall weight increases, as

does the pressure on the lowest levels. As a result, the lower

layers become increasingly compacted until they become new rock

formations known as sedimentary rocks.

Some types of sedimentary rock can be formed by the deposition

over millions of years of the skeletal material of billions of sea

creatures, e.g. vertebrate skeletons, invertebrate shells and corals.

2.1.4 Metamorphic Rock

the Earth's crust is not a fixed stable surface. The continents are

constantly in motion, albeit extremely slowly, floating on the molten

magma below. This activity causes both sedimentary and igneous

rock to be subjected to enormous forces of heat, pressure and

friction, resulting in a third type of rock known as metamorphic rock.

2.1.5 The Cycle of Rocks


Over millions of years, the process of formation of igneous,

sedimentary and metamorphic rocks, including mountain building

and erosion, are continuously repeated throughout the life of the

planet. This is known as the cycle of rocks.

2.2 ROCK STRUCTURES

2.2.1 General

As discussed in Section 2.1.4 above, the Earth's crust is continually

in motion. Among other effects, this movement results in

realignment of the strata, known as folds and faults.


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Figure 2-3 Types of Fold

Figure 2-4 Typical Fault


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2.2.2 Folds


When layers of sedimentary rock are upfolded into an arch-likeform, the structure is called an anticline. When the beds are

downfolded into a trough-like structure they are called synclines. If

an anticlinal structure is vertical so that it plunges in all directions it

is known as a dome. If a synclinal structure has a vertical axis such

that it dips inwards in all directions it is known as a basin.

2.2.3 Faults


Faults are formed when the compression or tension forces acting

on rock strata cause the layers to fracture. The rock on either side

of the fracture is then free to move up or down, displacing the strata

from their original positions. Faults range in size from just a few

centimetres to many hundreds of kilometres along the break line

(fault plane).


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1 Name the 3 basic types of rock.

2 Which of the above is of particular interest to the petroleum geologist?

3 What is the name of the molten rock at the centre

of the Earth?

(a) Sedimentary

(b) Mud

(c) Petroleum

(d) Magma

4 Name 4 forces of nature responsible for the erosion of igenous rock.

5 Fill in the missing words in the following sentence:

Movement of the Earth's crust results in realignment of the strata, known

as ........... and ........... .

a b c d



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6 Name 2 types of fold.

7 Consider each of the following sentences and state if true or false:

(a) The smallest faults found are in the order of one kilometre.

(b) The largest faults found are in the order of 100 metres.

(c) Faults range from a few centimetres to many hundreds of kilometres.


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SECTION 3

ORIGINS OF HYDROCARBON DEPOSITS


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3 ORIGINS OF HYDROCARBON DEPOSITS

Hydrocarbons, also known as fossil fuels, are organic substances formed from the

remains of plants and animals deposited millions of years ago over long periods of

time.

Although traces of hydrocarbons have been found in rocks more than 1 billion

(1 000 000 000) years old, it is considered that most petroleum was formed less than

500 million (500 000 000) years ago. Some deposits may have been formed as

recently as 10 million (10 000 000) years ago.

Hydrogen Hydrocarbon deposits are almost exclusively found in the sedimentary

beds deposited in ancient seas. These seas once covered much of the present day

land surfaces.

The process of converting buried organic matter to oil, gas or coal requires two main

factors: time and temperature, with pressure playing a subsidiary role.

The term cooking time is used to describe how long (millions of years) the buried

matter has been at sufficient temperature to undergo conversion to oil or gas. The

rate at which the conversion takes place doubles with every 10C rise in

temperature above 60C (the critical temperature below which conversion will not

take place).

Above a temperature of 120C the conversion process breaks down the organic

matter and any oil is formed into gas. The term oil window is applied to zones of

buried sediments that lie between 60C and 120C. Above 120C to 325C lies

the gas window. Both these zones are sometimes referred to as the kitchen as it is

within this area that oil and gas are formed, provided the cooking time is right.

Above 325C, hydrocarbons are destroyed and reduced to carbon or coke.

Sediments experience a rise in temperature as they are buried increasingly deeper

below the surface with the passage of time. Typically a 1C rise in temperature is

experienced for every 30 m of burial. The rate of increase in temperature with depth

is known as the geothermal gradient and varies from basin to basin.

Knowledge of the geothermal gradient is important as it determines the location in


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depth terms of the kitchen in which oil and gas will have been produced from the

original organic matter. Knowledge of earth movements is important as it determines

the length of time that the sediments have remained in the kitchen.

The longer a sediment has been buried, the lower the threshold temperaturerequired to convert its organic matter to oil. Jurassic sediment needs only 60C

threshold as it has had over 150 million years in which to cook. Tertiary sediment

needs a threshold of 80C to 100C as it may have had fewer than 60 million years

in which to cook.

Marsh gas is produced by degradation of organic matter at or near the surface and

at normal temperatures. While significant volumes are created in this way, it is rarely

trapped in geological structures to form an economic accumulation of natural gas.


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1 From what are hydrocarbons formed?

(a) Sulphur

(b) Coal

(c) Plant and animal remains

(d) Eroded igneous rock

2 Consider each of the following sentences and state if rue or false:

(a) Hydrocarbons have been found in rocks more than 1 000 000 000

years old.

(b) Hydrocarbons have been found in rocks more than 3 000 000 000

years old.

(c) Some hydrocarbon deposits may have formed as recently as 1 000

years ago.

(d) Some hydrocarbon deposits may have formed as recently as

10 000 000 years ago.

3 What are the 2 main factors in the process of converting buried organic matter

into oil, gas or coal?


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4 What is the critical temperature below which

conversion will not take place?

(a) 60C

(b) 120C

(c) 180C

(d) 325C

5 In the conversion process, what happens above 325C?

6 What is a zone of buried organic matter, at the

correct temperature for conversion to oil and/or

gas, known as?

(a) Gas cooker

(b) Sink

(c) Kitchen

(d) Cellar


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SECTION 4

SEDIMENTARY ROCK


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44 SEDIMENTARY ROCK

4.1 GENERAL

When considering new areas for hydrocarbon exploration, the geologist first

considers areas with sedimentary rock formation as it is in this type of rock

that petroleum is primarily found.

4.2 POROSITY AND PERMEABILITY

4.2.1 General

There are two basic rock properties to be considered in the searchfor hydrocarbons:

porosity

permeability.

4.2.2 Porosity

Porosity is the ability of a rock to hold fluids and is directly related to

the amount of space between the grain particles comprising the

rock. Porosity is quoted as a percentage.

4.2.3 Permeability

Permeability is the ability of a rock to allow fluid to flow through it.

Permeability is measured in millidarcies.


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4.2.4 Cementation

If silica (present in most sands) is present in the deposit it will

dissolve in any water contained in the deposit. Due to the effects of

heat, this silica solution will recrystallize between the rock particles.

If the deposit is sufficiently permeable, flow of water through the

particles may occur. Any carbonates dissolved in the water will also

be precipitated due to the higher temperature. These two

processes, silica recrystallization and carbonate precipitation, are

referred to as cementation as they act to bind the individual grains

together. In general, the deeper a rock has been beneath the

surface of the earth (which is not necessarily the depth at which it is

found) the greater will be the degree of cementation. This process

of pressure increase, temperature increase, and cementation, is

known as diagenisis. The greater the degree of cementation the

lower the porosity and the permeability.

4.3 TYPES OF SEDIMENTARY ROCK

4.3.1 General

There are four main types of sedimentary rock:

sandstone

shale

limestone

evaporites.

Sandstone and shale are known as clastics or rocks formed from

fragments of other rock. Limestone and evaporites are known as

chemical deposits as they are formed by chemical precipitation from

seawater.

Sandstone reservoirs are usually more porous than those of

limestone. The least consolidated, younger sandstones are more


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porous than the more tightly compacted, older or more deeply

buried formations.


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4.3.2 Sandstone

Sandstone consists of sand-sized grains composed predominantly

of quartz. Often cemented by a silica or carbonate cement. It is the

typical oil reservoir rock.

The degree of porosity in sandstone depends on grain size, grain

shape, the degree of sorting and the amount of cement. The

permeability of a rock does not always correlate directly with its

porosity but it is usually good in a clean porous sandstone.

4.3.3 Shale

Shale, including mudstone, claystone and siltstone, is composed of

silt-sized grains and smaller. Clay particles make up a large

percentage of the rock. It usually displays laminations parallel to

the bedding plane. Whilst the porosity of shale may often appear to

be as high as that of good sandstone, the pores are so small and

the pore throats so restricted that effective porosity is zero. The

rock is usually impermeable, unless it is fractured when it allows

flow or storage of hydrocarbons.

4.3.4 Limestone

Limestone is a general term for rocks containing at least 80% by

volume calcium or magnesium carbonates. It often occurs as a

bedded and distinctly jointed rock which is the consolidated

equivalent of limy mud, calcareous sand or shell fragments, or all

three in combination.

Usually it has no primary (or intrinsic) porosity. In time, a secondary

porosity may develop as a result of joints and cracks being

developed and enlarged by ground water action.

4.3.5 Evaporites

Evaporites have no porosity or permeability. Their ability to flow


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plastically has very important implications for geologists and drilling

engineers.


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1 Fill in the missing words in the following sentences:

(a) Porosity is the ability of a rock to .......... ..........

(b) Permeability is the ability of a rock to allow .......... to .......... through it.

2 What is the unit of measurement for permeability?

3 What are the 2 processes which together are referred to as cementation?

4 What are the 4 main types of sedimentary rock?

5 What are sandstone and shale known as?

(a) Clastics

(b) Elastics

(c) Clays

(d) Evaporites

6 What are the porosity and permeability properties

of evaporites?

(a) High

(b) Average

(c) Low


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(d) Zero


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SECTION 5

RESERVOIR FORMATION


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Figure 5-1 Oil Seeps


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Figure 5-2 Anticlinal Trap


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5 RESERVOIR FORMATION

As sediments are buried beneath the sea, their pore spaces fill with salt water. With

increasing depth, the muddy organic-rich rocks move into hydrocarbon generation.

Oil and gas is formed and is squeezed out of these source rocks, migrating by

various pathways, along fault planes, through permeable beds until it seeps to the

surface (refer to Figure 5-1) or it is trapped by an overlying impervious cap rock

(refer to Figure 5-2) so that it accumulates below it. The rock in which the

hydrocarbon accumulates is always permeable and porous. This is the reservoir

rock. Five essential requirements can be identified for the development of a

hydrocarbon reservoir:

mature source rock

migration route

impervious cap rock

permeable reservoir rock

trapping structure.

The hydrocarbon fluid displaces the salt water or brine in the pore spaces as it flowsupwards to fill the reservoir rock under the trap. Because the reservoir is originally

saturated with salt water, the petroleum migrating into it displaces some water,

leaving a film of water around the sand grains and leaving the smaller pores full of

water.

The operating force is capillary pressure so the smaller the opening, the more

difficult it is to displace water from the water-wet rock. Assuming a liquid

hydrocarbon with its gas phase in solution, if the initial porosity is 25%, the pores willtypically contain 80% hydrocarbon and 20% water.


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Figure 5-3 Migration of Petroleum


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In attempting to recover the oil, the same capillary forces work in reverse and often

only 30% of the oil in place can be recovered to the surface, the rest being trapped in

the smaller pore spaces (refer to Figure 5-3).

There are several different geological situations that can give rise to suitable traps.

Traps can be formed by folding rock into an anticline (refer to Section 2.2.2). The

formation of salt domes (refer to Figure 5-4) is another mechanism, as is faulting. A

trap may result from a change in the type of sediment being laid down (known as a

stratigraphic trap).

There is almost an infinite variety of geological conditions that can combine to form a

trap. When studying a trap, the geologist attempts to find out what geological

conditions had to develop for it to form.

Commercial hydrocarbon deposits are classified as accumulations, fields and

provinces. The simplest unit of commercial occurrence is the accumulation. It is

defined as the body of oil or gas, or both, occurring in a separate reservoir and under

a single pressure system. An accumulation may be small, underlying only a few

hectares, or it may extend for many square kilometres. Its content may be entirely

gas, or it may be entirely or mainly oil.

When several accumulations are related to a single geological feature, either

structural or stratigraphic, the group of accumulations is termed a field. The

individual accumulations in a field may occur at various depths, one above another,

or they may be distributed laterally throughout the geological feature.

The petroleum reservoir is the part of the rock that contains the accumulation of oil.

The location of every oil and gas accumulation may be said to be the result of

complex or interrelated geological conditions. Each reservoir is unique in its details.


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Figure 5-4 Salt Dome Formation


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1 What are the 5 essential requirements for the development of a hydrocarbon

reservoir?

2 If the initial porosity of a reservoir rock is 25%,

what would be a typical ratio of hydrocarbon to water?

(a) 50 : 50%

(b) 70 : 30%

(c) 80 : 20%

(d) 90 : 10%

3 Name a geological condition which could result in the formation of a trap.

4 Fill in the missing words in the following sentence:

Commercial hydrocarbon deposits are classified as .........., .......... and

..........


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5 Consider the following sentences and state if true or false:

(a) An accumulation may range in size from 10 square kilometres to

hundreds of square kilometres.

(b) An accumulation is usually less than 1 hectare in size.

(c) The content of an accumulation is always gas and oil in equal

proportions.

(d) An accumulation may range in size from a few hectares to many

square kilometres.


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SECTION 6

EXPLORATION


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Figure 6-1 Seismic Surveying


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6 EXPLORATION

6.1 EXPLORATION METHODS

By carefully plotting the landscape, the geologist can predict the type of

structure beneath which a reservoir may lie. Study of the surface rock

composition helps this prediction. Aerial survey can narrow down the search

by showing faults otherwise not noticeable at ground level, provided such

faults are exposed.

If geological and aerial surveys give strong indications, a seismic survey may

be carried out. The seismic survey team looks for the presence of cap rock

by measuring echoes. A charge of explosive is fired into the ground and the

time taken for the echo to return is noted (refer to Figure 6-1). If cap rock is

present, the echo returns quickly and sharply; the sooner the echo returns,

the nearer is the cap rock. There are other types of formation which return

echoes but the seismic team is able to differentiate between them by the

sharpness and timing of the echo.

By repeating these soundings over the area selected by the geologist, the

seismic team is able to draw an underground map and establish the presenceof caps and potential reservoirs. Exploration drilling is, however, the only

means of confirming (or denial) of the presence of a hydrocarbon reservoir.

6.2 DRILLING PROPOSAL

Before an oil company drills into a trap it must decide if that trap could contain

sufficient volume of hydrocarbons to make the venture worthwhile. This

requires a knowledge of the typical distribution of fluids in a reservoir.


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A detailed geophysical and geological prognosis of the prospective structure

must, therefore, be made and upon this is based an estimated chance of it

containing hydrocarbons. The likely volume of recoverable hydrocarbons isestimated as follows:

1 Estimate the volume of reservoir rock enclosed by the trap.

2 Assuming typical porosity and oil/gas saturation, estimate the total

oil/gas in place.

3 Apply an average recovery factor and allow for volume change in

bringing the oil/gas to surface temperature and pressure.

Armed with this estimated recoverable oil volume, the oil company is then in a

position to decide if the prospect is worthwhile drilling in terms of the likely

return on the investment.

6.3 TYPES OF WELL

6.3.1 Wildcat Wells

The geologist must decide where the first wells should be drilled, to

test if his assumptions are correct.

In a new basin or a previously undrilled area, this well is known as a

wildcat well or exploration well, its purpose being to give the

geologist access to the formation he would like to test for oil or gas

accumulation.

6.3.2 Appraisal Wells

If the wildcat well finds oil or gas, further wells may be required to

allow an accurate assessment of the volumes of oil or gas present.

These are known as appraisal wells or stepout wells.


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The following information is required before a decision can be made to

develop an accumulation:

(a) Level of the top of the oil-bearing formation.

(b) Level of the top of the gas zone (possibly the same as (a) above).

(c) Level of the bottom of the gas zone.

(d) Level of the top of the liquid zone, if present (possibly the same as

(c) above).

(e) Level of the bottom of the liquid zone.

(f) Level of the top of the water zone, if present (possibly the same as (e)above).

(g) Rock samples of producing zones from which porosity and permeability

can be determined.

Several appraisal wells may be required before the extent of the hydrocarbon

reservoir can be fully assessed.

The information from these appraisal wells allows maps to be producedshowing gas/oil evaluations and oil/water elevations (assuming the three-

phases exist in the reservoir). Thus, as reservoir porosity is already known,

an 'oil in place' volume can be calculated.


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In assessing the potential financial returns from a potential reservoir, it must

be remembered that a reservoir can rarely be made to produce more than

30% of its contents without pumping or other assistance. In some cases the

figure is much smaller. Even with assistance, a reservoir can rarely be made

to produce more than 50% to 60% of its contents. No method has yet been

devised to enable the final 30% or so to be extracted.


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1 What is the purpose of aerial surveying?

2 Upon what principle is seismic surveying based?

(a) Echo returns

(b) X-rays

(c) Chromatography

(d) Photography

3 In which order are the following types of well drilled?

(a) Appraisal well

(b) Development well

(c) Exploration well

4 What is the name of the test used to establish (among other data) the gas/oil

ratio?

5 What percentage of a reservoir's content can be produced without pumping or

other assistance?

a b c d



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Module 3 Final - HYDROCARBON AND RESERVOIR GEOLOGY

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Transcript of Module 3 Final - HYDROCARBON AND RESERVOIR GEOLOGY