Well Logging Fiinal (Delete Reservoir) Flashcards
So far, only the NMR response to water-filled pore space has been discussed.
- 100% water is said to have an hydrogen index (HI) of ____.
- Oil, light oil, and gas have fewer hydrogen atoms per unit volume than water and are therefore said to have an hydrogen index (HI) of ____.
conventional electrode tools use an array of ___ electrodes with letters of ____
describe the azimuth convention on a tadpole plot
what is the pad contact CMR tool
What is NMR Echo Train – CPMG Pulse Sequence
Describe the Archie equation variable “n”
what are the different ways of presenting the results of a dipmeter survey
•By convention, when more than one curve is recorded on the same track, the ____ curve represents the response of the tool with the deeper radius of investigation.
what do hydrogen molucules look like without a magnetic field nearby
Describe the laminated shale method graphically
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what is the resistivity ratio
describe the three basic NMR measurements
The vertical precision of NMR tools depends on
give a quick overview of the overlay of curves SP With Rxo/Rt
•When the lithology and, therefore, the matrix parameters (t_ma, ρ_ma, ∅_ma) are known, correct porosity values can be derived from these logs, in _____
The M-N crossplot requires a ___log, _____log, and ____log
•T1 Relaxation, also known as _____relaxation, or relaxation in the z-direction
what are the 2 limiations of conventional electrode-type devices
what is the archie equation for resistivity
Borehole imaging tools - desciribe Wireline Imaging Tools. Electrical Imaging
for a conventional electrode tool in the ____ arrangement, two electrodes are mounted on a sonde.
the term porosity tools includes…
what is the photoelectric capture cross-section
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The very first logging device ever designed was made to measure _____.
describe the procedure to apply the overlay of curves SP With Rxo/Rt
what do hydrogen atoms look like when a magnetic field is applied to them
•The photoelectric absorption index (Pe) of an atom _____ with increasing atomic number Z.
what is Ohm’s law
what are the 4 clays types
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what is a dip angle
•Accurate porosity determination is more difficulty when
describe how a basic downhole resistivity measurement works
what does F represent in terms of resisitivty
what are the types of methods to determine water saturaiton
what is an NMR tipping pulse
what is the Humble equation relating rock porsoity and resistivity
Wireline imaging devices rely on two measurement principles:
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what is quick look log analysis
what is water saturation
what are laterologs used for
•In addition to the bulk density (ρ_b), lithology density tools also measure the ______of the formation.
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Each practical logging tool involves a trade-off between ____, which can be extrapolated fieldwide only at great risk of inaccuracy, and ____, which is blind to local inhomogeneities
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what is arps equation for equivalent resistivity for a given temp
what is a dip azimuth
what are laminated shales
what are compatible overlays of curves
The measurements of the neutron, density, and sonic logs depend on
F depends on the ____ and the _____ of the rock
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what are the 2 ways to define shales
What are some salient features of a conventional electrode “electric log”
what is a dipmeter designed to measure
what is a convetional electrode tool “electric log”
name the classificiation of resistivity logs
what is a laterolog-3
what are azimuth frequency diagrams
how does a conventional electrode tool “lateral device” work
what is an orbital magnetic dipole moment
The effect of shale on the response of standard logging tools depends on:
•The NMR measurement of T2 is a distribution over time of a series of values that gives the analyst a picture of the ______and the _____
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- Sonic log measures only ____porosity (intergranular & intercrystalline);
- Neutron and Density logs measure ____porosity;
describe the physics of NMR (sequience of events)
describe the basic NMR measurements and what they’re converted to
•______ can significantly influence the response of all three porosity logs (neutron, density, and sonic logs):
what is conductance
how does an induction log work
what is compaction factor
If the trace could be “unwrapped” and laid on a flat surface, a ____wave would be visible, with its ____reflecting the dip magnitude and its ____ indicating the dip azimuth.
what is crossplot extrapolation and frequency plots
picture of 4 arm dipmeter
what is a SODA plot
what are the 2 types of raw data surveyed from a dip meter
The value of the _____, generally is different from the formation true resistivity, Rt . It is usually a value between Rt and the resistivity of the flushed zone, Rxo
What 3 plots are used to produce the Neutron-Density Crossplot
what are the 3 types of quick look analysis
what is sonic porosity
how is dip azimuth read on a tadpole plot
What are the M-N plot shortcomings
The overall term for the observed loss of phase coherence (de-phasing) is _____, which combines the effect of _______ and additional dephasing caused by local variations (inhomogeneities) in the applied magnetic field.
what are structural shales
describe the patterns to observe when applying the overlay of curves SP With Rxo/Rt
Describe the sand/shale sequence model
a printout of dipmeter results usually has what 3 things
During NMR after a tipping pulse, the realignment of protons that are close to a solid surface (a sand grain for example) proceeds ____, but protons in the middle of a pore and far from a solid surface realign more ____
Pad contact CMR tool
•By changing the frequency of the RF pulse used to flip the protons, this tool can make measurements at ______ radially outward from the tool into the formation, as illustrated in figure.
describe how the exponents of the archie equation vary
•Devices that measure porosity are sensitive both to the ____ and to the ____.
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what are the 2 types of NMR tools
what is resistivity
•Electrode devices, either conventional or focused current, require the presence of ____fluid in the borehole.
In a MID plot,
- The neutron and density logs are combined to define an _____
- The neutron and sonic logs are combined to define an _____
All types of dipmeters have 4 common characteristics
what are the 4 levels of log interpretation
Archie’s equations relating Rock Resistivity and Fluid Saturation are not the best for shaly sand, what equation is?
How does the NMR Centered Magnetic Resonance Imaging Logging (MRIL® ) Tool-Halliburton work
Dipmeter: provides valuable insights into the structural and sedimentary features of the reservoir, they lack the ____ that a full borehole image can provide
NMR measurements may be applied to several different parts of the overall formation evaluation task, including
name some types of resistivity logs
Broadly speaking, dip interpretation may be split into two parts:
describe the neutron density overlay
Describe neutron density cross plot
what is a borehole High-definition formation microimager (FMI-HD)
•Litho-density tools (LDTs) are improved and expanded versions of ______
what are stratigraphic plots
what is the difference between clay and shale
what are resisitivty logs used for
All of the conventional tools measure ____and _____ indirectly, except NMR log.
describe the photoelectric effect
The MID plot requires what logs
The contribution of each of the four zones to the calculated value of the Ra is determined by the _____ and _____ and the ______.
•Reservoir rocks in situ are almost always conductors, which results from the presence of ____.
what is a crossplot
what is archie’s emperical relationship between m, phi, and F
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During NMR log interpretation, The analyst should be able to pick, in conjunction with other ancillary data such as a ____, depth intervals with good porosity and permeability
Centered Magnetic Resonance Imaging Logging (MRIL® ) Tool-Halliburton uses multiple ______ to also investigate a range of annular volumes of the formation at different distances from the tool axis, as illustrated in this figure.
what is a microlog
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Describe the structured approach to well log analysis
what is a folded structure
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describe the Uncertainties of Conventional Log Analysis model for shaly sand analysis
Describe the clean formation model
The sonic-density plot is the ____ desirable of the lithology plots
what are th 4 physical models for analysis of shaly sand logs to produce quantitative results?
•Laterologs are designed to measure formation resistivity in boreholes filled with ____ (where Rmf~R w ) .
name some typical resistivity ranges
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for a conventional electrode tool in the ____ arrangement, three electrodes are on the logging tool..
The ratio method for water saturation calcs assumes that
what is a dual laterolog
Describe the laminated shale model
The conductivity of a solution depends on:
NMR can be used to measure what
The presence of clay minerals or shale in porous formations presents problems from the interpretation of wireline logs. •The problem is, however, especially bad in the interpretation of ____ data, and also affects the ____ logs.
With the exception of the photoelectric factor measurement, Pe, and the natural gamma ray spectral log, no single tool measurement will by itself give a direct indication of _____
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what are the applications of dipmeters
what is apparent resistivity
During NMR, For any given measurement cycle, the _____over time of the received signals is an indicator of the number of protons (and hence of porosity) and their distribution (and hence of the pore sizes involved).
describe ultrasonic borehole imager
how is the dip magnitude read from a tadpole plot
how does a conventional electrode tool “normal device” work
Both ____ and ____ are exponential processes with times constants ___ and ____ respectively. This is the time at which the magnetization has decayed to 37% of its initial value immediately after the 90° RF pulse
The recovery of Mz is an ____process with a time constant T1 .
With CMR, it is common to use a slightly different relationship to calculate permeability. • Instead of using the Coates equation (given in Eq. 19.1), the ______ is used as the input to the equation
Note that the NMR and Conventional Log Analysis Models have six components: matrix and dry clay, which together sum to give the ____; clay-bound water, capillary-bound water, free water, and hydrocarbon, which together sum to give the ____
To apply quantitative analysis to well logs, some _____model is required to relate the log response to the mineral and fluid contents of the formation and their distribution therein.
Name the 4 types of models
what are the most common overlay curves
describe the 3 types of ultrasonic borehole imagers
What is NMR T2 relaxation
what is conductivity
The induction tool does not require ____ fluid in the borehole or ____ with the formation.
NMR alone cannot perform a complete analysis that includes free and bound-water saturations; _______ devices are still needed.
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In NMR, The general form of the equation relating permeability and the measured quantities is:
Describe the ratio method for water saturation calculations
what is borehole imaging deployed
Describe the overlay curve Ro with Rt with an F overlay
what is an NMR calibration parameter
•NMR measurements are not confined to deducing rock properties because the same NMR principles can be applied to fluids. _____ can be measured for a fluid in a container large enough that surface relaxation effects are insignificant.
In addition to confirmation of bed dip angle and azimuth, _______ provide textural information, thus pinpointing vugs, fractures, and other fine sedimentary details unobtainable from dipmeters alone.
Oil and gas are insulators / conductors.
• NMR tools, of whatever type, can, at best, make measurements near the borehole in the _____ where mud filtrate has invaded and the saturation is Sxo.
From a nuetron desnity crossplot, Lithology identification is accomplished by observation of density neutron ____and the gamma ray ____
describe the Uncertainties of Conventional Log Analysis
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• The basic level of formation evaluation with an NMR log is:
what is archie’s equation
The MRIL NMR tool is run centered in the borehole and is less affected by borehole ____ than the padcontact devices
•Igneous, metamorphic and dry sedimentary rocks are _______ of electrical conductors
In NMR, the term _____describes how signals change with time. In general signals deteriorate with time, becoming weaker and broader.
what is a Laterolog-7?
what are inductance tools
The most useful cominations of logs to find lithology are
When a density log is missing or suffers from bad hole effects, the _____ plot should be used
neutron sonic plot
what 3 things must be determined before reading a porosity log
- The ___ and ____ clays are part of the rock structure and are considered to have the same porosity (water content) as adjacent clay beds because they were subjected to the same overburden pressures.
- By contrast, the ____ clays were only subjected to the formation fluid pressure, and therefore have a higher porosity and water content
what was the first resistivity log
_____ enables a lithological interpretation to be
made without prior knowledge of porosity.
what are dispersed shales
what are electrode tools
Conventional electrode, focused-current, or induction tools are used to measure the ________ of formations penetrated by a borehole
what are the archie equations comapring the relationship between Rock Resistivity and Fluid Saturation
