1. MSc. Badees Gazal
نالوت جامعة
-
النفط هندسة قسم
الغاز و
جــادو
-
ليبيــــــا
Nalut University – Oil & Gas Engineering Department
Jadu-Libya
2. Formation Evaluation Specialist
The Formation Evaluation Specialist must have a
general knowledge of:
•Fundamental measurement theory for logging
devices
•Log quality control
•Basic log interpretation principles
•Fundamentals of geophysics and petroleum
geology
•Fundamental principles of petroleum engineering
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3. •Log Analyst - analyzes well log data
•Petrophysicist - analyzes the physical properties of
rocks and how they relate to measurable properties
•Formation Evaluation Specialist - has a general
knowledge of all the formation evaluation
disciplines, including wireline, MWD, mud logging,
coring, sampling, pressure tests, seismic, etc.
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4. Log Response
Logs respond mostly to rock porosity and
chemistry therefore a chemical rock classification
is more suitable to log analysis;
•Rocks composed mostly of silica are generally
described as sandstones
•Calcium carbonates -- Limestones
•Calcium Magnesium Carbonates -- Dolomites
•Rock mixtures of clays & silts -- Shales
•Anhydrite, halite, gypsum, and coal have rather
unique log signatures
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5. Be Aware That
No logging device measures porosity, saturation,
permeability, or fluid type directly. Logs do not
identify color of rock or define the texture of rock.
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6. Nevertheless,
Some logging devices respond to properties that
are related to porosity, saturation, permeability,
or fluid type.
Combinations of different log measurements often
define the above --- plus lithology!
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7.
8. WHAT IS WELL LOG ?
Defined as a continuous record of measurement made in bore hole
respond to variation in some physical properties of rocks through which
the bore hole is drilled(Porosity, permability, water saturation).
Traditionally Logs are display on girded papers, now a days the log may
be taken as films, images, and in digital format such as (LAS or ASCII).
9. WELL LOG HISTORY
1912 Conrad Schlumberger give the idea of using electrical measurements to
map subsurface rock bodies.
In 1919 Conrad Schlumberger and his brother Marcel begin work on well logs.
The first electrical resistivity well log was taken in France, in 1927.
In 1929 the electrical resistivity logs are introduce on commercial scale in
Venezuela, USA and Russia For correlation and identification of Hydrocarbon
bearing strata.
The dip meter log were developed in 1930, the photographic – film recorder
was developed in 1936.
Gamma Ray and Neutron Log were begin in 1941.
10. First Well Log Sept 5, 1927, Pechelbronn France
Inventors of Well Logging: Conrad and Marcel Schlumberger
15. The zone in which much of the original fluid is replaced by mud filtrate is called the
invaded zone. It consists of resistivity Rxo, Rmf and Sxo.
INVASION OR FLUSHED ZONE
16. It is occurs where a formation’s fluids and mud filtrate are mixed, some of
original pore water and hydrocarbons, if present, have been replaced by
mud filtrate but significant quantities remain.
TRANSITION ZONE
17. The area beyond the invaded zone where a formation’s fluids are
uncontaminated by mud filtrate, instead, they are saturated with formation
water (Rw), (Rt), (Sw).
NON INVISION ZONE
18. Using Log Information
•Courts often recognize well logs as legal
documents
•Header information is mostly take from other well
records
•Some of the header information is very critical to
log analysis
•Used effectively, the remarks section can explain
questions regarding log quality, not reaching total
depth, etc.
•Tool numbers can also be important
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23. Depth Measurements
•The most fundamental wireline measurement
•Very important to the success of any wireline
operation
•Tolerance is expected to be within +/- 1 ft. / 10,000
ft.
(A detailed description is given in Appendix “A” of
the text)
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24. 24
Minute Time Markers Indicate
Logging Speed Versus Depth
(ft/min or m/min) 60 seconds
10 feet
Log record covered 26 ft.
In 60 seconds
> Logging Speed = 26 ft. / minute
or 1,560 ft. / hour
Logging Speed
