Patent Document ID: 10119387
Application ID: 14891438
Patent Status: 1

Claim One:
1. A method comprising: measuring in a wellbore having a casing an acoustic impedance via a pulse echo measurement and a flexural attenuation via a pitch-catch measurement obtaining acoustic cement evaluation data points deriving from the pulse echo and pitch catch measurements, wherein the acoustic cement evaluation data points each comprise a first component representative of a flexural attenuation, wherein the first component is the flexural attenuation or a flexural-attenuation-derived acoustic impedance, and a second component representative of a pulse-echo-derived acoustic impedance; processing the acoustic cement evaluation data points using a solid-liquid-gas model to assign at least some of the acoustic cement evaluation data points to a material of solid, liquid, or gas in an annulus of the wellbore behind the casing, wherein the solid-liquid-gas model comprises a first solid-liquid-gas model in which a gas threshold range comprising acoustic cement evaluation data points assigned to represent gas in the annulus is not directly adjacent to a liquid threshold range comprising acoustic cement evaluation data points assigned to represent liquid in the annulus, wherein the first solid-liquid-gas model comprises a range not providing a threshold indication of liquid, solid, or gas, the range being disposed between the gas threshold range and the liquid threshold range and corresponding to patchy dry debonding of cement behind the casing, determining based on the processed cement evaluation data points the nature of a material behind the casing, wherein the nature of the material includes one of the following: solid, liquid or gas.