SPE Formation Evaluation and Logging 2

Question 1

Which neutron log measurement is most directly affected by the presence of gas in the formation?

Accepted Answer

Decreased neutron porosity reading

Answer

Increased neutron porosity reading

Answer

No change in neutron porosity

Answer

Increased bulk density reading

Question 2

What is the primary purpose of a caliper log in formation evaluation?

Accepted Answer

Determining borehole diameter and shape

Answer

Measuring formation fluid salinity

Answer

Estimating formation permeability

Answer

Measuring formation temperature gradient

Question 3

In a density-neutron crossplot, a gas crossover occurs when:

Accepted Answer

Density porosity exceeds neutron porosity

Answer

Neutron porosity exceeds density porosity

Answer

Both logs read identical porosity values

Answer

Both logs read zero porosity

Question 4

The formation factor (F) in Archie's equation relates to which petrophysical property?

Accepted Answer

Cementation and tortuosity of pore space

Answer

Water saturation

Answer

Formation temperature

Answer

Irreducible water saturation

Question 5

Which log is most commonly used to identify fractures in a formation?

Accepted Answer

Fullbore Formation MicroImager (FMI)

Answer

Spontaneous Potential (SP) log

Answer

Compensated Neutron Log (CNL)

Answer

Gamma Ray (GR) log

Question 6

What does a high spontaneous potential (SP) deflection (toward negative millivolts) typically indicate?

Accepted Answer

A permeable, porous sand with fresh formation water

Answer

A shale or tight formation

Answer

A zone with high oil saturation

Answer

An overpressured formation

Question 7

Invasion of mud filtrate into a formation primarily affects which logging measurements?

Accepted Answer

Shallow and medium resistivity measurements

Answer

Deep resistivity only

Answer

Neutron and density logs exclusively

Answer

Gamma ray and SP logs only