Method for determining if a wellbore consists of micro annulus, free pipe or solid bonding between the wellbore and a casing

• Main Authors: Jørgensen, Erlend Kvinge, Malmberg, Jenny-Ann, Sirevaag, Tore Lie, Støa, Stig
• Format: Patent
• Language: English
• Published: 09.07.2024
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS; PHYSICS; TESTING

Material properties between a wellbore and a casing having a partition separating respective domains inside and outside the casing are evaluated by disposing at least one ultrasonic transmitter and a plurality of ultrasonic receivers in longitudinally spaced-apart relationship alongside the partition inside the casing. The ultrasonic transmitter is activated to form ultrasonic waveforms comprising propagated quasi leaky-Lamb waves constituting flexural waves having symmetric and antisymmetric zero-order modes within the partition. A time-shift is applied to the received flexural waves so that the respective time-shifted waveforms corresponding to each of the flexural waves arrive at the same time. The time-shifted waveforms are clustered 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 allowing determination of a material and geometry behind the partition.