Question:
Which of the following statements pertaining to the interpretation of Neutron log is/are CORRECT ?
Which of the following statements pertaining to the interpretation of Neutron log is/are CORRECT ?
Show Hint
Neutron logs are sensitive to hydrogen content; interpret them considering fluid types (liquid vs. gas) and formation pressure effects.
Updated On: Aug 22, 2025
- Overpressured shale shows very low neutron porosity
- Neutron log primarily measures liquid (water/oil) filled porosity
- Neutron porosity for a gas-bearing clean sandstone formation is lower than the actual porosity of the same formation
- A low neutron porosity indicates high Hydrogen Index of the formation
Hide Solution
Verified By Collegedunia
The Correct Option is B, C
Solution and Explanation
Step 1: Analyze each statement based on the principles of neutron log interpretation:
- A neutron log measures the hydrogen content in a formation, which is indicative of porosity when the pores are filled with fluids (water or oil) that contain hydrogen.
- The neutron porosity reading can be affected by the type of fluid and the formation characteristics.
Step 2: Evaluate option (A):
- Overpressured shale typically has higher porosity due to compaction effects, and neutron logs tend to show higher neutron porosity in such cases, not very low. Thus, (A) is incorrect.
Step 3: Evaluate option (B):
- The neutron log primarily measures the porosity filled with liquids (water or oil) because these fluids have a high hydrogen content that slows down neutrons. This is a correct statement, so (B) is correct.
Step 4: Evaluate option (C):
- In a gas-bearing clean sandstone formation, the neutron porosity is lower than the actual porosity because gas has a lower hydrogen index compared to liquids. This causes the neutron log to underestimate the porosity, making (C) correct.
Step 5: Evaluate option (D):
- A low neutron porosity indicates a lower hydrogen content, which corresponds to a lower Hydrogen Index, not a high one. Thus, (D) is incorrect.
Step 6: Conclusion:
- The correct statements are (B) and (C).
Was this answer helpful?
0
0
Top Questions on Geophysical Well Logging
Questions Asked in GATE GG exam
- Rohit goes to a restaurant for lunch at about 1 PM. When he enters the restaurant, he notices that the hour and minute hands on the wall clock are exactly coinciding. After about an hour, when he leaves the restaurant, he notices that the clock hands are again exactly coinciding. How much time (in minutes) did Rohit spend at the restaurant?
- The sum of the following infinite series is: \[ 1 + \frac{1}{1!} + \frac{1}{2!} + \frac{1}{3!} + \frac{1}{4!} + \frac{1}{5!} + \dots \]
- GATE CH - 2025
- GATE BT - 2025
- GATE GG - 2025
- Sequence and Series
- A thin wire is used to construct all the edges of a cube of 1 m side by bending, cutting, and soldering the wire. If the wire is 12 m long, what is the minimum number of cuts required to construct the wire frame to form the cube?
A color model is shown in the figure with color codes: Yellow (Y), Magenta (M), Cyan (Cy), Red (R), Blue (Bl), Green (G), and Black (K). Which one of the following options displays the color codes that are consistent with the color model?
- Consider a two-dimensional reflection experiment, where a horizontal boundary between two layers is at a depth of 500 m below the free surface. A source and geophone are placed on the free surface with an offset of 2000 m. The P-wave velocity of the top layer is 3000 m/s. The travel time of a recorded free-surface reflection multiple, which got reflected twice at the free surface, is ________ s.
- GATE GG - 2025
- Seismology
View More Questions