CPG CPG Formation Evaluation & Petrophysics

Question 1

Which petrophysical equation is most commonly used to calculate water saturation from resistivity logs in clean sandstone formations?

Accepted Answer

Archie's equation

Answer

Waxman-Smits equation

Answer

Dual-water model

Answer

Indonesia equation

Question 2

What does the neutron-density crossplot primarily identify in formation evaluation?

Accepted Answer

Lithology and gas-bearing zones

Answer

Permeability and flow rate

Answer

Formation pressure gradients

Answer

Fault orientations

Question 3

In petrophysics, the term 'cementation exponent' (m) in Archie's equation typically ranges from what values for consolidated sandstones?

Accepted Answer

1.8 to 2.0

Answer

0.5 to 1.0

Answer

3.0 to 4.0

Answer

0.1 to 0.5

Question 4

Which log measurement is the primary direct indicator of formation fluid pressure in permeable zones while drilling?

Accepted Answer

Repeat Formation Tester (RFT) / MDT

Answer

Gamma ray log

Answer

Sonic log

Answer

Caliper log

Question 5

What is the primary purpose of the photoelectric factor (Pe) log in formation evaluation?

Accepted Answer

Lithology identification

Answer

Porosity calculation

Answer

Permeability estimation

Answer

Fluid contact detection

Question 6

Which core analysis measurement distinguishes macroporosity from microporosity in carbonates?

Accepted Answer

Mercury injection capillary pressure (MICP)

Answer

Routine helium porosity

Answer

Klinkenberg-corrected permeability

Answer

Dean-Stark water saturation