On an acoustic image log, a fracture is most commonly represented as which shape?

On an acoustic image log, a fracture is most commonly represented as which shape?

• A. Straight line
• B. Zigzag
• C. Elliptical curve
• D. Sinus curve

Answer: (D)

A planar fracture cutting a circular borehole shows up as a sinusoidal trace on an acoustic image log. This happens because the borehole wall is circular and the log maps that wall around depth, so when a flat fracture plane intersects the hole, the line where the fracture meets the wall wraps around the circle in a wave-like (sinusoidal) pattern. The depth at which the fracture is seen around the circumference shifts sinusoidally with azimuth, and the dip of the fracture affects the wavelength and amplitude of that wave. In short, the geometry of a plane intersecting a cylinder naturally produces a sinusoidal trace on the image, which is why that shape best represents a fracture on an acoustic image log.

A planar fracture cutting a circular borehole shows up as a sinusoidal trace on an acoustic image log. This happens because the borehole wall is circular and the log maps that wall around depth, so when a flat fracture plane intersects the hole, the line where the fracture meets the wall wraps around the circle in a wave-like (sinusoidal) pattern. The depth at which the fracture is seen around the circumference shifts sinusoidally with azimuth, and the dip of the fracture affects the wavelength and amplitude of that wave. In short, the geometry of a plane intersecting a cylinder naturally produces a sinusoidal trace on the image, which is why that shape best represents a fracture on an acoustic image log.