Question

Match the following wire-line logging methods (GROUP I) based on the physical principles of measurements (GROUP II). 

• A. P – II, Q – I, R – IV, S – III
• B. P – III, Q – I, R – IV, S – II
• C. P – III, Q – II, R – IV, S – I
• D. P – II, Q – I, R – III, S – IV

Hint:

Wire-line logs are essential tools for evaluating subsurface formations based on physical properties like electrical conductivity, radioactivity, elastic wave propagation, and hydrogen nuclei behavior.

Answer 1

The Correct Option is B

Wire-line logging is a technique used to evaluate subsurface formations. Here's a breakdown of the physical principles associated with each type of log: - Induction Log (P): The induction log measures the electrical resistivity or conductivity of the formation. It is based on the principle of measuring how much the induced electromagnetic field in the formation resists the passage of electrical current. Therefore, it matches with Group II (III), which refers to measuring electrical resistivity/conductivity. - Gamma-Ray Log (Q): The gamma-ray log measures the natural radioactivity of the formation. It detects gamma rays emitted by radioactive materials in the formation, primarily from isotopes like potassium-40 and thorium. This corresponds to Group II (I), which measures natural radioactivity. - Sonic Log (R): The sonic log measures the elastic wave propagation properties of the formation. It is used to determine the velocity of sound waves traveling through the formation, which can provide information about the porosity and lithology. This aligns with Group II (IV), which deals with elastic wave propagation properties. - Nuclear Magnetic Resonance (S): The NMR log measures the induced magnetic moment of hydrogen nuclei (protons) in the formation. It is used to assess the formation's porosity, permeability, and fluid content by measuring how hydrogen atoms in water respond to a magnetic field. This matches Group II (II), which measures the induced magnetic moment of hydrogen nuclei. Therefore, the correct matching is (B): P – III, Q – I, R – IV, S – II.