In order to improve shale-bond logging interpretation, we perform laboratory experiments on hollow cylinder shale samples with acoustic logging in a cased hole, permeability measurement in the annulus, and stress and pressure control of the sample and hole.
SINTEF is developing own acoustic logging tool, a downscaled version of the standard cement bond logging tools. The results from our experiments may be therefor applicable to the cement bond logs run in the field today. We also use numerical simulations tailored to study logging through casing to design experiments and to help interpretation of the measurements.
We conduct material characterization under stress/ pressure and strain control using ultrasonic measurements. Acoustic properties (velocities) of the shale are measured under triaxial conditions similar to the stress state in the shale making a barrier around the casing.