Isolation Scanner cement evaluation service combines classic pulse-echo technology with the new ultrasonic technique of flexural wave imaging to accurately evaluate any type of cement, from traditional slurries and heavy cements to the latest lightweight cements. This innovative method provides precise, real-time evaluation of the cement job and casing condition in a wider range of conditions than previously possible with conventional technologies.
The Isolation Scanner tool’s combination of independent measurements fully characterizes the annular environment, differentiating low-density solids from liquids to distinguish lightweight and contaminated cements from liquids. Its azimuthal coverage provides an answer around the entire circumference of the casing, pinpointing any channels in the cement and confirming the effectiveness of a cement job for zonal isolation.
Processing provides a robust interpreted image of the material immediately behind the casing. The independent inputs of the Isolation Scanner cement impedance and flexural wave attenuation are invertibly related to the properties of both the fluid inside the casing and the outside medium. This means that fluid effects are accounted for, eliminating the need for logging specific fluid-property measurements. The output is a solid-liquid-gas (SLG) map that displays the most likely material behind the casing.
Isolation Scanner service also identifies corrosion or drilling-induced wear through measurement of the inside diameter and thickness of the casing.
The addition of the flexural measurement produces entirely new information from the third-interface echoes (TIEs) between the annulus and the borehole or outer casing. The TIEs image the borehole shape, define the position of the casing within the borehole or outer casing, and image the outer string to reveal corrosion and damage. This previously unavailable geometrical information for the cased hole environment helps in assessing casing and cementing techniques, choosing cut points on casing retrieval jobs, and providing context for other evaluation services run through casing.