Numerical simulation study of the sonic detection and imaging methods for fish top in downhole environments

Area of Science:

• Petroleum Engineering
• Acoustics
• Geophysical Well Logging

Background:

• Fishing and docking fractured drill tools in deep and ultra-deep wells presents significant challenges due to difficulties in precise localization.
• Existing methods often suffer from low efficiency and accuracy in complex downhole environments.

Purpose of the Study:

• To develop and validate a novel acoustic imaging method for accurately locating the top of fractured drill tools (fish).
• To enhance the efficiency and success rate of fishing operations in challenging wellbore conditions.

Main Methods:

• Employed a line-array scanning method utilizing acoustic transducers to generate images of the fish top.
• Established a casing-fish annulus space model based on borehole acoustic theory.
• Analyzed acoustic wave propagation, one-dimensional linear array receiving properties, and reflection echoes.

Main Results:

• Acoustic imaging successfully identified the fish top in both horizontal and inclined well sections.
• Demonstrated high accuracy with a 2% error for the fish top center in horizontal sections.
• The method revealed the inclined orientation of the fish in inclined sections.

Conclusions:

• The line-array acoustic imaging method provides an effective solution for locating fractured drill tools.
• Achieved successful imaging with a reduced number of acoustic transducers, enhancing operational efficiency.
• Offers a valuable reference for the development of advanced downhole tools and systems.