US 12,031,425 B2
Method for determining if a wellbore consists of micro annulus, free pipe or solid bonding between the wellbore and a casing
Jenny-Ann Malmberg, Billingstad (NO); Erlend Kvinge Jørgensen, Oslo (NO); Tore Lie Sirevaag, Oslo (NO); and Stig Støa, Oslo (NO)
Assigned to Equanostic AS, Oslo (NO)
Filed by Equanostic AS, Oslo (NO)
Filed on Aug. 8, 2022, as Appl. No. 17/818,020.
Prior Publication US 2023/0039040 A1, Feb. 9, 2023
Int. Cl. E21B 47/005 (2012.01); G01N 29/11 (2006.01)
CPC E21B 47/005 (2020.05) [G01N 29/11 (2013.01); G01N 2291/044 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for determining material properties between a wellbore and a casing, said casing having a wall forming a partition that separates a first domain inside the casing from a second domain outside the casing, the method comprising:
disposing at least one ultrasonic transmitter and a plurality of ultrasonic receivers in longitudinally spaced-apart relationship along a first side of the partition in the first domain;
activating the at least one ultrasonic transmitter to form ultrasonic waveforms that comprise propagated quasi leaky-Lamb waves constituting flexural waves having symmetric and antisymmetric zero-order modes within the partition;
receiving and recording the ultrasonic waveforms at the spaced-apart receivers;
applying a time-shift to the recorded ultrasonic waveforms so that the respective time-shifted waveforms corresponding to each of the flexural waves arrive at the same time;
clustering the time-shifted waveforms to form separate clusters respectively relating to a flexural wave part, and at least one post-flexural wave part which exposes characteristics that would otherwise be hidden behind more dominant features in the flexural wave; and
using said characteristics to establish a material and geometry behind the partition.