US 11,726,225 B2
Detection and evaluation of ultrasonic subsurface backscatter
Roger Steinsiek, Houston, TX (US); Hermanus J. Nieuwoudt, Tomball, TX (US); Brian A. Moody, New Iberia, LA (US); and Andal Pierre, Woodlands, TX (US)
Assigned to BAKER HUGHES OILFIELD OPERATIONS LLC, Houston, TX (US)
Filed by Roger Steinsiek, Houston, TX (US); Hermanus J. Nieuwoudt, Tomball, TX (US); Brian A. Moody, New Iberia, LA (US); and Andal Pierre, Woodlands, TX (US)
Filed on Nov. 3, 2020, as Appl. No. 17/88,321.
Claims priority of provisional application 62/932,215, filed on Nov. 7, 2019.
Prior Publication US 2021/0140305 A1, May 13, 2021
Int. Cl. G01V 1/50 (2006.01); E21B 47/095 (2012.01); G01V 1/00 (2006.01); E21B 47/002 (2012.01); G01V 1/30 (2006.01); E21B 49/00 (2006.01)
CPC G01V 1/50 (2013.01) [E21B 47/0025 (2020.05); E21B 47/095 (2020.05); E21B 49/00 (2013.01); G01V 1/001 (2013.01); G01V 1/306 (2013.01); G01V 2210/43 (2013.01); G01V 2210/624 (2013.01); G01V 2210/6244 (2013.01); G01V 2210/6246 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A system for estimating a property of a region of interest, comprising:
an acoustic measurement device configured to be disposed in a region of interest in an earth formation, the acoustic measurement device including a transmitter configured to emit an acoustic signal having at least one selected frequency configured to penetrate a surface of a borehole and produce internal diffuse backscatter from earth formation material behind the surface and within the region of interest, and a receiver configured to detect return signals from the region of interest and generate return signal data; and
a processing device configured to receive the return signal data, the processing device configured to: process the return signal data to identify internal diffuse backscatter data indicative of the internal diffuse backscatter by gating a portion of the return signal data occurring after one or more initial pulses in the return signal data associated with surface reflections; calculate a probability distribution function of the gated portion of the return signal data, and estimate an entropy value based on the probability distribution function; and estimate the property of the region of interest based on the estimated entropy value.