PP6 Finals

Total volume of pores

Porosity is defined as:

Permeability

Has no universal relationship to porosity

100%

If only water exists in a formation with Φ = 30%, the S_w is

decrease

Other factors remaining constant, with the increase in salinity of the formation water, the R_w will

Correct answer: R_t(1) < R_t(2) = R_t(3)

1. R_t(1) = R_t(2) = R_t(3)
2. R_t(1) < R_t(2) < R_t(3)
3. R_t(1) < R_t(2) = R_t(3)
4. R_t(1) = R_t(2) < R_t(3)

shale adds to the conductivity

Archie’s equation does not give the correct results in shaly sand since

R_t in shale

Φ_t in shale

In Dual Water Model, the R_(WB) is computed using

lower than that calculated from Archie’s equation, especially if the BQ_v is High

In shaly sand, the S_w calculated from the Waxman-Smits equation will be

gamma rays

of the three particles generated during a radioactive decay only


1. Alpha particles
2. beta particles
3. gamma rays

can penetrate the rock for an appreciable distance to be measured by a detector

low

Clean sands usually have a ______ Gamma Ray reading


1. Low
2. High

high

shales have a _______ Gamma ray reading


1. low
2. high

very little activity

When R_w = R_(mf) the SP log shows what?

left, right

The SP log will deflect to the ________ in the clean water bearing san compared to the shale when R_(mf) > R_W and will deflect to the _______ when R_(mf) < R_w.

does not

PEF is a good lithology incator when the mud


1. does
2. does not

contain Barite

time

Surface Seismic data is acquired to view the sub-surface as a function of?

to find the depth to time relationship

The primary objective of acquiring the Check-shot survey is

the complete geophone waveform

The VSP survey requires the acquisition of

increases

The sonic DT


1. increases
2. decreases
3. remains same

with the increase in shaliness of water bearing sandstone

is

The T2 relaxation time distribution obtained from the NMR log


1. is
2. is not

affected by viscosity of oil present in the pore spaces

Hydrogen atom’s nuclear magnetic properties

What property of Hydrogen atoms is used by Nuclear Magnetic Resonance logging

has negligible effect on density-neutron separation

Heavy oil in sands


1. has negligible effect on density-neutron separation
2. increases the density-neutron log separation
3. decreases the density-neutron log separation

decreases the density-neutron log separation

Increase of Shaliness in Gas bearing Sands


1. has no effect on density-neutron log
2. increases the density-neutron log separation
3. decreases the density-neutron log separation

separate with neutron log on the right of density log

In Gas bearing sandstone the density and neutron log


1. separate with neutron log on the right of density log
2. separate with neutron log on the left of the density log
3. neutron and density log overlay
4. gas has no effect on either neutron or density logs

should not

MSFL service


1. should
2. should not

be run in oil based mud

Dual Laterolog

In very saline drilling mud environments ________ will be the preferred service

\

reduces

The invasion process


1. reduces
2. increases
3. does not change

the hydrocarbon saturation in the zone near the borehole in the hydrocarbon bearing permeable beds when drilled with water based mud

It is independent of lithology

The main advantage of NMR porosity over porosity from other tool is that ____

increases

The NPHI


1. Increases
2. Decreases
3. remains the same

with the increase in shaliness of water bearing sandstone.

has very little effect

Increase in shaliness of the water bearing sandstone


1. increases
2. decreases
3. has very little effect
4. on the computation of Φ_e from the density log

1. density neutron separation
2. wireline formation tests

The preffered tools for gas/oil differentiation are:

Too high

If you apply a fluid density of 1.0 in a gas bearing zone, the porosity calculated from the density will be:


1. Too high
2. too low
3. can’t say; depends on other parameters.

1. porosity
2. water saturation
3. shaliness
4. formation water resistivity

The resistivity of a reservoir depends on:

pickett plot

To determine the formation water resistivity from the resistivity log in a water zone

sands from GR, porosity and HC type from density/neutron, saturation from deep resistivity

the correct quicklook procedure is to evaluate

True

The main limitation of determining permeability from the standard wireline formation tester is that the pressure pulse created is too small to give a reliable permeability measurement.


1. True
2. False

True

In NMR measurements the value of the T_2 is almost proportional to the pore size in the rock.


1. True
2. False

stoneley waves

Which of the sonic waves responds primarily to the formation permeability?

Separate

Permeability is indicated by the MicroLog tool when the Micro-Normal and Micro-Inverse curves

cannot

Standard Wireline Formation Testers


1. can
2. cannot

obtain PVT quality formation fluid samples

3, 4

Which of the following transmitter-receiver combinations is used to derive the formation compressional slowness in open hole?

Photo-electric absorption

Of the three Gamma ray interactions:


1. Pair production
2. Compton scattering
3. Photo-electric absorption

which of them is of interest to us for determining lithology?

R_(mf) = R_w

the mud is oil based

the borehole is cased

The SP log cannot be recorded when:


1. R_(mf) > R_w
2. R_(mf) = R_w
3. R_(mf) < R_w
4. the mud is oil based
5. the borehole is cased

Electrochemical potential

The SP log recording is measuring the:

PEF

Presence of KCL in mud will have least effect on the _____

SP

Presence of barite in mud will have the least effect on the:

radioactive clean sand

In a shale-sand reservoir, a zone with high SGR and low CGR represents:

potassium

uranium

thorium

The naturally occurring radioactive elements which decay spontaneously resulting in a measurable Gamma ray signal are radioactive:


1. hydrogen
2. carbon
3. potassium
4. sodium
5. chlorine
6. uranium
7. thorium

protons & neutrons

The nucleus of an atom consist of _____

inaccuracy in the determination of reservoir size

The main source of uncertainty in the determination of reservoir hydrocarbon volume is normally the:


1. inaccuracy in the determination of reservoir size
2. inaccuracies and errors in logs and log evaluation
3. inaccuracies and errors in the determination of the oil formation volume factor

2

inversely proportional

the response of the neutron detectors are ____ to the porosity of the formation.


1. proportional
2. inversely proportional

A minitron produces more neutron

Why would a tool that is designed to measure epithermal neutrons be better off using a minitron rather than a chemical source?


1. A mintron is more reliable
2. A minitron produces neutrons in the epithermal energy range
3. A minitron produces more neutrons
4. Both the detector and the minitron could use the same power supply
5. it would not be better off

0\.4 to 10eV

What is the epithermal nuetron energy range

1,2,3

Which characteristics of a neutron make it a good instrument for logging applications?


1. It has no charge
2. It has a mass similar to that of a proton
3. Its depth of penetration is relatively large

Density of the matrix

average density of the saturating fluids

For determination of porosity from the density log in clean water-bearing formation, which of the following values have to be known?


1. Density of the matrix
2. average density of the saturating fluids
3. hydrogen index of the matrix
4. average hydrogen index of the saturating fluids

True

Density porosity measures primary as well as secondary porosity.


1. True
2. False

True

In a standard density log presentation, the mud-cake correction is usually applied.


1. True
2. False

4

electron density

Density tools measure:


1. formality bulk density
2. electron density
3. apparent formation density

1,2

What is the reason for using more than one detector in the density or neutron tool?


1. Larger detector-to-source spacing allows for a more accurate measurement; in contrast, a smaller detector-to-source spacing allows for a higher resolution measurement
2. to compensate for borehole effects

4

False

Sonic porosity measures primary as well as secondary porosity


1. True
2. False

Water sample from a Drill stem Test in the Water zone

Which of the following sources of water resistivities will be the most reliable?


1. Local Knowledge
2. Water sample from a Wireline Formation Tester in the water zone
3. Water sample from a Drill stem Test in the Water zone
4. SP log
5. R_t and Φ data in the water zone
6. R_(mf), R_(xo)and R_t data in the water zone

None of the above

Which of the following logs will provide correct porosity in a formation with single known mineral and residual gas?


1. neutron log as standalone
2. densit log as standalone
3. NMR log as standalone
4. None of the above

2

\

False

The T_2 cut-off value which is used to determine the free fluid porosity is independent of the lithology


1. True
2. False

True

The NMR porosity is independent of lithology


1. True
2. False

the pore fluid only

The NMR measurement responds to the hydrogen atoms present in:


1. the pore fluid only
2. the rock matrix only
3. both the pore fluid and the rock matrix

show a separation with density curve to the right of the neutron curve

A density-neutron log is presented in a sandstone compatible scale and neutron porosity computed with constant MATR=SAND. In a clean water bearing limestone, the density and neutron curves will:


1. overlay
2. show a separation with density curve to the left of the neutron curve
3. show a separation with density curve to the right of the neutron curve

1,2,3

For a two mineral water-filled formation which values are required to compute the porosity from the density-neutron log?


1. matrix density of the two minerals
2. neutron porosity response of the two minerals
3. density and neutron porosity of the mud filtrate

False

The neutron porosity tool is often used as standalone to evaluate the formation porosity.


1. True
2. False

both

The neutron tool responds to the hydrogen atoms present in:


1. only the pore fluid.
2. only the rock matrix.
3. both.

borehole size.

NPHI output is usually corrected for which of the following environmental conditions?


1. borehole size.
2. borehole pressure.
3. formation salinity.
4. Mud-cake thickness.
5. borehole salinity.
6. mud weight.
7. borehole temperature.
8. all of the above

True

Neutron porosity measures primary as well as secondary porosity


1. True
2. False

Ramp Invasion profile

What kind of an invasion model does AIT log use to compute R_t?

IDPH < IMPH

In an oil-based mud, for an 8" hole which of the following statements is true, in a clean water bearing invaded zone?


1. IDPH > IMPH
2. IDPH = IMPH
3. IDPH < IMPH

oil-based mud

The induction tools will work best in:


1. saline mud
2. fresh water mud
3. oil-based mud

Step invasion profile

What kind of an invasion model does DLL, ARI and HALS log use to compute R_t?

HRLA

Which of the following tools is not affected by the tool string length effect, the Groningen effect and the TLC effect?


1. DLT-E
2. ARI
3. HALS
4. HRLA

LLD= LLS = MSFL

If R_t > R_m, in an 8" hole which of the following statements is true in a shale (non-invaded) zone?


1. LLD > LLS > MSFL
2. LLD= LLS = MSFL
3. LLD

LLD >LLS > MSFL

If R_w > R_(mf) (saline mud), in an 8" hole which of the following statements is true for a clean water bearing invaded zone?


1. LLD >LLS > MSFL
2. LLD =LLS = MSFL
3. LLD < LLS < MSFL

saline mud

The laterolo tools will work best in:

cannot

The Micro-resitivity log:


1. can
2. cannot

be acquired in an oil-based mud

as an indicator of invasion.

The Microlog data is used:


1. as an indicator of invasion.
2. for R_(xo) determination.
3. for mud-cake thickness determination.
4. for mud-cake resistivity determination

can

shaly-sand matrix has no effect on TCMR and gas has an effect to decrease the TCMR.

Total CMR porosity (TCMR) and density log:


1. can
2. cannot

identify the presence of gas in a shaly-sand formation since :


3. shaly-sand matrix and gas has no effect on TCMR.
4. shaly-sand matrix has no effect on TCMR and gas has an effect to decrease the TCMR.
5. shaly-sand matrix has an effect to increase the TCMR and gas has no effect on TCMR.
6. shaly-sand matrix has an effect to increase the TCMR and gas has an effect to decrease the TCMR

False

The T_2 distribution can always be used for hydrocarbon typing in water wet rocks.


1. True
2. False

only the hydrogen nuclei in the pore fluid that are polarized by B_o

The oscillating magnetic field B, tip:


1. all the nuclei in the pore fluid that are polarized by Bo
2. only the hydrogen nuclei in the pore fluid that are polarized by B_o

all the nuclei with a magnetic moment in the pore fluid

The B_o static magnetic field affects:


1. all the nuclei
2. all the nuclei with a magnetic moment
3. all the nuclei with a magnetic moment in the pore fluid
4. only the hydrogen nuclei
5. only the hydrogen nuclei in the pore fluid

in the volume of investigation.

environmentally-corrected and lithology-corrected density porosity

environmentally-corrected and lithology-corrected neutron porosity

invaded zone hydrocarbon saturation

To find the hydrocarbon density from density-neutron logs and the Schlumberger chart-book, you need:


1. raw density
2. raw neutron porosity
3. environmentally-corrected and lithology-corrected density porosity
4. environmentally-corrected and lithology-corrected neutron porosity
5. hydrogen index of water
6. hydrogen index of hydrocarbon
7. invaded zone hydrocarbon saturation

increases

Density-Neutron log separation:


1. increases
2. decreases
3. remains the same

when gas replaces oil in a clean sandstone

forward modeling and inversion

The best technique to interpret horizontal well logs is:


1. via chart books and manually solving equations.
2. forward modeling and inversion

False

The resistivity anisotropy will only affect the 2MHz log and not an induction log in a horizontal well.


1. True
2. False

False

The depth of investigation for a CDR/ARC5 tool is fairly constant over a wide rage of resistivities.


1. True
2. False

DLT

Which of the following tools would you prefer to run in a tight carbonate formation drilled with saline mud?


1. DLT.
2. DIT.
3. AIT.

Timur-Coats equation

In a gas bearing sandstone the:


1. Timur-Coats equation
2. SDR equation

will provide a better permeability estimate

high

Water bearing formations with long T2 times are expected to have:


1. high
2. low

permeability

Stoneley slowness and attenuation over the wide frequency spectrum

The Stoneley Mobility Inversion technique uses:


1. Stoneley slowness over the wide frequency spectrum
2. Stoneley attenuation over the wide frequency spectrum
3. Stoneley slowness and attenuation over the wide frequency spectrum

in its model to obtain fluid mobility

reduces

The presence of mud-cake:


1. reduces
2. enhances

the effect of formation fluid mobility on (S-S_e).

Wireline Formation Tester

Stoneley measurements.

\

Which of the following can provide a direct measure of permeability?


1. Wireline Formation Tester.
2. Nuclear Magnetic Resonance measurements.
3. Stoneley measurements.
4. Invasion measurements

not certified

The conventional sample chambers are:


1. certified
2. not certified

for transportation of pressurised fluids