Question

The logging tool(s) preferred for the measurement of formation resistivity in a well drilled with oil-based mud is/are:

• A. Dual Laterolog
• B. Compensated Neutron Log
• C. Compensated Density Log
• D. Induction Log

Hint:

Induction logs are ideal for measuring resistivity in oil-based mud, as they are less influenced by mud conductivity compared to other tools.

Answer 1

The Correct Option is D

Step 1: Understanding the measurement of formation resistivity.
Formation resistivity is typically measured to assess the porosity and fluid content of the formation. When drilling with oil-based mud, tools that are not affected by the mud’s conductivity are preferred. v Step 2: Evaluating the options.
- Option (1): Dual Laterolog: This tool is typically used with water-based mud and may not be as effective with oil-based mud.
- Option (2): Compensated Neutron Log: This is used to measure hydrogen content and porosity but does not measure resistivity directly.
- Option (3): Compensated Density Log: This tool is used for density and porosity measurements but is not directly related to resistivity.
- Option (4): Induction Log: The induction log is effective for measuring formation resistivity in oil-based mud because it uses electromagnetic induction, which is less sensitive to mud type. This is the correct tool for the job.
Thus, the correct answer is (4).