The document provides an introduction to well log interpretation. It discusses key concepts such as identifying clean zones using gamma ray and resistivity logs, determining porosity using density, neutron, acoustic and NMR logs, and identifying hydrocarbon presence based on resistivity. It also covers estimating hydrocarbon quantity from water saturation, and evaluating recoverability by comparing flushed and true zone resistivities. The borehole environment and its impact on invasion zones is also summarized.
Introduction
Petrophysic of the rocks
It is the study of the physical and chemical properties of the rocks related to the pores and fluid distribution
Porosity, is ratio between volume of void to the total voids of the rock.
Permeability, is ability of a porous material to allow fluids to pass through it.
Electric, most of the sedimentary rocks don’t have conductivity.
Radiation, clay rocks have 40K, radiate alpha ray.
Hardness, it depends on the cementing material and thickness of the sediments.
WELL LOGGING
The systematic recording of rock properties and it’s fluid contents in wells being drilled or produced to obtain various petrophysical parameters and characteristics of down hole sequences (G.E Archie 1950).
The measurement versus depth or time, or both, of one or more physical properties in a well.
These methods are particularly good when surface outcrops are not available, but a direct sample of the rock is needed to be sure of the lithology.
A wide range of physical parameters can be measured.
In some cases, the measurements are not direct, it require interpretation by analogy or by correlating values between two or more logs run in the same hole.
Provide information on lithology, boundaries of formations and stratigraphic correlation.
Determine Porosity, Permeability, water, oil and gas saturation.
Reservoir modeling and Structural studies… etc.
Types of Well Logging
Logs can be classified into several types under different category
Permeability and lithology Logs
Gamma Ray log
Self Potential [SP] log
Caliber log
Porosity Logs
Density log
Sonic log
Neutron log
Electrical Logs
Resistivity Log
For contact : omerupto3@gmail.com
The spontaneous potential log, commonly called the self potential log or SP log, is a passive measurement taken by oil industry well loggers to characterise rock
Introduction
Petrophysic of the rocks
It is the study of the physical and chemical properties of the rocks related to the pores and fluid distribution
Porosity, is ratio between volume of void to the total voids of the rock.
Permeability, is ability of a porous material to allow fluids to pass through it.
Electric, most of the sedimentary rocks don’t have conductivity.
Radiation, clay rocks have 40K, radiate alpha ray.
Hardness, it depends on the cementing material and thickness of the sediments.
WELL LOGGING
The systematic recording of rock properties and it’s fluid contents in wells being drilled or produced to obtain various petrophysical parameters and characteristics of down hole sequences (G.E Archie 1950).
The measurement versus depth or time, or both, of one or more physical properties in a well.
These methods are particularly good when surface outcrops are not available, but a direct sample of the rock is needed to be sure of the lithology.
A wide range of physical parameters can be measured.
In some cases, the measurements are not direct, it require interpretation by analogy or by correlating values between two or more logs run in the same hole.
Provide information on lithology, boundaries of formations and stratigraphic correlation.
Determine Porosity, Permeability, water, oil and gas saturation.
Reservoir modeling and Structural studies… etc.
Types of Well Logging
Logs can be classified into several types under different category
Permeability and lithology Logs
Gamma Ray log
Self Potential [SP] log
Caliber log
Porosity Logs
Density log
Sonic log
Neutron log
Electrical Logs
Resistivity Log
For contact : omerupto3@gmail.com
The spontaneous potential log, commonly called the self potential log or SP log, is a passive measurement taken by oil industry well loggers to characterise rock
WELL LOG : Types of Logs, The Bore Hole Image, Interpreting Geophysical Well Logs, applications, Production logs, Well Log Classification and Cataloging
well logging project report_ongc project studentknigh7
It briefs well logging basics for students of geophysics on well logging or partly on reservoir characterization. It can be good note book for summer ,winter training in well logging data analysis and open hole log interpretation
A small presentation about wireline logs, showing their function or the technology that they use.
Ruhr-Universität Bochum, Petroleum Geology II, Winter Semester 2013/2014.
Evaluating storage capability of reservoir using an integrated source-free in...Fabio Brambilla
The traditional approach of evaluation requires running density and neutron log devices in order to have quantitative estimation of reservoir porosity. Both logs response are affected by lithology and gas presence
NMR log-calibrated acoustic porosity provides more accurate and detailed description of reservoir porosity
Advanced logging evaluation gas reservoir of Levantine basinFabio Brambilla
Experience gained in recent activity in the Levantine basin has allowed for the development of a formation evaluation strategy for accurate gas reservoirs description in this region. The proposed evaluation approach considers operational issues of deep water wells, challenging borehole conditions (high salinity mud, deep invasion) and other geological features of these clastic reservoirs and their fluids. Our case study highlights benefits of the integrated evaluation of new laterolog resistivity data together with 2D NMR inversion results optimized for a gas bearing reservoir. Furthermore borehole imaging logs are included in our evaluation approach. The recently developed multi laterolog tool has an advantage of four multiple depths of investigation. It provides a detailed high 1ft vertical resolution radial resistivity profile overcoming the deep invasion often present in these reservoirs. The NMR acquired in gas oriented acquisition mode exploits the multi-frequency capability of the logging device. Combined together multiple G•TE and multiple TW experiments contribute to robust determination of the T1 and T2 reservoir fluid properties. This acquisition sequence allows for continuous hydrocarbon typing applying the T1/T2 vs T2 2D maps method, which is practical for these reservoirs given the T1 contrast between gas and other fluids. Consequently we are able to perform accurate HI corrections and therefore improve the estimates of NMR permeability and saturations. Further in the workflow we compare NMR and Stoneley wave permeability’s and assess in details their differences. The geological study performed with the combination of simultaneously acquired ultrasonic and resistivity borehole images provides additional insight into the reservoir architectures, taking advantage during the analysis of the different logging responses of the petrophysical factors to acoustic and resistivity investigation for a detailed delineation of the productive beds. The advantages of this integrated approach are illustrated with field data examples.
Well logs can be states as “a recording against depth of any of the characteristics of the rock formations traversed by a measuring apparatus in the well-bore.”
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
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Palestine last event orientationfvgnh .pptxRaedMohamed3
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We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
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3. 1. Rudimentary definitions
2. hydrocarbons presence determination
3. hydrocarbons quantity and recoverability
determination
4. The Borehole Environment
4.
5. wellsite interpretation
wellsite interpretation refers to the rapid and
somewhat cursory approach to
scanning an available set of logging measurements,
and the ability to identify and draw some conclusion
about zones of possible interest.
The three most important questions to be
answered by wellsite interpretation are:
hydrocarbons presence, depth and type (oil or gas)
hydrocarbons quantity
hydrocarbons recoverability
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
5
6. logging measurements
and petrophysical parameters
A schematic
representation
of
the logging
measurement
s used
and the
petrophysical
parameters
determined
for answering
the basic
questions of
wellsite
interpretation
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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7. Fundamental definitions
In order to see how logging
measurements shows
hydrocarbons contents, a few
definitions must first be set out.
Porosity φ
Water saturation, Sw
oil saturation, So, is 1 − Sw
The irreducible water saturation,
Swirr,
residual oil saturation, Sor,
oil that cannot be moved without
resorting to special recovery
techniques
a unit volume of rock
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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8. true resistivity
The resistivity (a characteristic akin to resistance) of
a formation is a measure of the ease of electric
conduction.
The resistivity of the undisturbed region of
formation, somewhat removed from the borehole,
is denoted by Rt , or true resistivity.
The formation resistivity Rt is derived from
measurements that yield an apparent resistivity.
These measurements can then be corrected, when
necessary, to yield the true formation resistivity.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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9. Rxo, Rw and Rmf
In the region surrounding the wellbore,
where the formation has been disturbed by the invasion
of drilling fluids,
the resistivity can be quite different from Rt .
This zone is called the flushed zone, and
its resistivity is denoted by Rxo.
Two other resistivities will be of interest:
the resistivity of the brine, Rw,
which may be present in the pore space,
and the resistivity of the filtrate of the drilling fluid, Rmf ,
which can invade the formation near the wellbore and
displace the original fluids.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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10.
11. hydrocarbons presence requirements:
No shale
To find hydrocarbons presence,
the selection of an appropriate zone must be addressed.
It is known that formations with low shale content
are much more likely to produce accumulated
hydrocarbons.
Thus the first task is
to identify the zones with a low-volume fraction of shale
(Vshale),
also known as clean zones.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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12. Methods to identify clean zones
Two traditional measurements
the gamma ray, and
The gamma ray signal will generally increase in magnitude
according to the increase in shale content.
the spontaneous potential (SP)
The qualitative behavior of the SP
(a voltage measurement reported in mV) is to become less
negative with increases in formation shale content.
Other recent techniques
the separation between the neutron and density
measurements,
the nuclear magnetic resonance (NMR) distribution, and
elemental spectroscopy analysis.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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13. hydrocarbons presence requirements:
Porosity (density tool)
The formation can contain hydrocarbons only if the
formation is porous.
Four logging devices yield estimates of porosity.
In the case of the density tool,
the measured parameter is the formation bulk density ρb.
As porosity increases, the bulk density ρb decreases.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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14. hydrocarbons presence requirements:
Porosity(neutron, acoustic, NMR tools)
The neutron tool
is sensitive to the presence of hydrogen.
Its reported measurement is the neutron porosity φn,
which reflects the value of the formation hydrogen content.
The acoustic tool
It measures the compressional wave slowness or,
interval transit time t (reported in μs/ft).
It will increase with porosity.
NMR
The total NMR signal depends on the amount of hydrogen and
therefore increases with porosity.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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15.
16. Formation hydrocarbon contamination
Once a porous, clean formation is identified, the analyst is
faced with deciding whether it contains hydrocarbons or
not.
This analysis is done in quite an indirect way, using the
resistivity Rt of the formation. If porous formation contains
conductive brine => low resistivity
a sizable fraction of nonconducting hydrocarbon => rather large Rt
However, there is also an effect of porosity on the resistivity.
As porosity increases, the value of Rt will decrease if the water
saturation remains constant.
The hydrocarbons may be oil or gas.
The distinction is most easily made by comparing
the formation density and neutron porosity measurement.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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17. hydrocarbons quantification
To determine the quantity of hydrocarbon present
in the formation,
the product of porosity and saturation (φ × Sw)
must be obtained.
For the moment, all that need be known is that
the water saturation Sw
is a function of both formation resistivity Rt and porosity φ.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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18. hydrocarbons recoverability
determination
Another common resistivity measurement, Rxo,
corresponds to the resistivity of the flushed zone,
a region of formation close to the borehole,
where drilling fluids may have invaded and displaced the original
formation fluids.
The measurement of Rxo is used to get some idea of
the recoverability of hydrocarbons.
If the value of Rxo is the same as the value of Rt ,
then it is most likely that the original formation fluids are
present in the flushed zone,
• so no formation fluid displacement has taken place.
if Rxo is different than Rt ,
then some invasion has taken place,
and the fluids are movable.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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19. hydrocarbons recoverability
determination
This can be taken one step further.
If the ratio of Rxo to Rt is the same as
the ratio of the water resistivities in the two zones
(Rmf and Rw),
then the flushed and non-flushed zones
have either the same quantity of hydrocarbons or none.
Any hydrocarbons are unlikely to be producible in this
case.
If the ratio of Rxo to Rt
is less than that of Rmf to Rw,
then some hydrocarbons have been moved
by the drilling fluid and will probably be producible.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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20. A summary of
phenomenological interpretation
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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21.
22.
23. borehole environment importance
and ranges
The borehole environment is of some interest from the
standpoint of
logging tool designs and
the operating limitations placed upon them
the disturbance it causes in the surrounding formation
in which properties are being measured.
Some characterization of the borehole environment
can be made using the following set of generalizations.
Well depths are ordinarily between 1,000 and 20,000 ft,
Well diameters ranging from 5 to 15 in.
the deviation of the borehole is generally between 0◦ and 5◦
• More deviated wells, between 20◦ and 60◦ are often encountered
offshore.
The temperature, at full depth,
ranges between 100◦F and 300◦F.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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24. borehole environment importance
and ranges (Cont.)
Since the early 1990s an increasing number of
horizontal wells have been drilled.
These are drilled at a suitable deviation down to near the top
of the reservoir, at which point the deviation is increased until
they penetrate the reservoir within a few degrees of
horizontal.
They are then maintained within 5◦ of horizontal between
1,000 [305m] and 5,000 ft [1.5km].
The drilling fluid density is between 9 and 16 lb/gal;
weighting additives such as barite (BaSO4) or hematite
are added to ensure that the hydrostatic pressure
in the wellbore exceeds the fluid pressure in the formation
pore space to prevent disasters such as blowouts.
The salinity of the drilling mud ranges between 1,000 and
200,000 ppm of NaCl.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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25. result of the invasion process
The generally
overpressured wellbore
causes invasion of
a porous and
permeable formation
by the drilling fluid.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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26. invasion
In the permeable zones, due to the imbalance in hydrostatic
pressure, the mud begins to enter the formation but is
normally rapidly stopped by the buildup of a mud cake of
the clay particles in the drilling fluid.
This initial invasion is known as the spurt loss.
As the well is drilled deeper, further invasion occurs slowly
through the mudcake,
either dynamically, while mud is being circulated,
or statically when the mud is stationary.
In addition, the movement of the drill string can remove
some mudcake, causing the process to be restarted.
Thus, while a typical depth of invasion at the time of wireline
logging is 20 in. [51cm] , the depth can reach 10 ft [3m] or more in
certain conditions.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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27. nomenclatures
To account for the distortion which is frequently
present with electrical measurements,
a simplified model of the borehole/formation
in vertical wells with horizontal beds has evolved.
It considers the formation of interest, of resistivity Rt,
to be surrounded by “shoulder” beds of resistivity Rs .
the mudcake of thickness hmc and
resistivity Rmc
annular region of diameter di is the flushed zone
whose resistivity is denoted by Rxo,
determined principally by the resistivity of the mud filtrate.
Beyond the invaded zone lies
the uninvaded or
virgin zone with resistivity Rt .
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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28. Schematic model of
the borehole and formation
used to
describe
electriclogging
measuremen
ts and
corrections
Courtesy of
Schlumberger.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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29. transition zone
A transition zone separates the flushed zone from
the virgin zone.
The invaded zone was originally described as a
succession of radial layers starting with Rx0, and
followed by Rx1, Rx2, etc.
The numerical portion of the subscript was originally supposed
to indicate the distance from the borehole wall, e.g., Rx1
indicated 1 in. into the formation.
Rx0 was the resistivity at the borehole wall,
but over time this became Rxo and the other distances fell out
of use
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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30. transition zone (Cont.)
The transition may be smooth,
but when hydrocarbons are present its resistivity can be
significantly lower than either Rxo or Rt .
This condition is known as an annulus and
occurs mainly when the oil or gas is more mobile than the
formation water,
• so that the formation water displaced from the flushed zone
accumulates in the transition zone
• while the oil or gas is displaced beyond it.
The annulus disappears with time,
• but can still exist at the time of logging.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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31. step-profile model
The simplest model,
known as the step-profile model,
ignores the transition zone and
describes the invaded zone in terms of just two parameters,
the resistivity Rxo and
the diameter di .
This model also assumes azimuthal symmetry around
the borehole.
In a horizontal well gravity cause heavier mud filtrate to sink
below the well, leaving more of the lighter oil or gas above it.
Gravity effects can also affect the fluid distribution around
deviated wells or in highly dipping beds.
Fall 13 H. AlamiNia
Well Logging Course: Introduction to Well Log Interpretation
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32. Distribution of pore fluids in zones
around a well
The model is valid for both
wireline and LWD logs.
LWD logs are normally recorded a
few hours after a formation is
drilled,
and therefore encounter less invasion
than that seen by the wireline logs,
• which may be recorded several days
after drilling.
However this is not always the case:
initially contained
hydrocarbons
Fall 13 H. AlamiNia
some LWD logs are recorded later
while the drill string is being run out
of the hole from a deeper total
depth.
Well Logging Course: Introduction to Well Log Interpretation
32
33. 1. Ellis, Darwin V., and Julian M. Singer, eds. Well
logging for earth scientists. Springer, 2007.
Chapter 2