Which two logs can be combined to identify a breakout?

Which two logs can be combined to identify a breakout?

• A. Caliper logs and Image logs
• B. Gamma ray logs and Neutron logs
• C. Mud logs and Density logs
• D. Resistivity logs and Sonic logs

Answer: (A)

Breakouts are localized enlargements of the borehole wall caused by differential stress. To identify them, you need both a measurement of hole size and a direct view of the wall. Caliper logs record the borehole diameter as you run the tool; when a breakout occurs, the diameter increases in that interval, showing up as a bulge on the caliper record. Image logs give a high-resolution image of the borehole wall, so you can visually confirm breakouts as elongated, planar features and see their orientation. Using both together provides the evidence of where the hole has widened and what the wall looks like, making breakout identification reliable. Other logs focus on rock type, porosity, or fluid properties (like lithology from gamma and neutron, or formation properties from density, resistivity, and sonic, or drilling conditions from mud logs). They don’t directly show borehole-wall enlargements, so they’re not as effective for spotting breakouts.

Breakouts are localized enlargements of the borehole wall caused by differential stress. To identify them, you need both a measurement of hole size and a direct view of the wall. Caliper logs record the borehole diameter as you run the tool; when a breakout occurs, the diameter increases in that interval, showing up as a bulge on the caliper record. Image logs give a high-resolution image of the borehole wall, so you can visually confirm breakouts as elongated, planar features and see their orientation. Using both together provides the evidence of where the hole has widened and what the wall looks like, making breakout identification reliable.

Other logs focus on rock type, porosity, or fluid properties (like lithology from gamma and neutron, or formation properties from density, resistivity, and sonic, or drilling conditions from mud logs). They don’t directly show borehole-wall enlargements, so they’re not as effective for spotting breakouts.