ConocoPhillips and Statoil Petroleum have signed a joint-sponsorship-development agreement with Visuray Technology to fund development of a downhole cement-integrity-evaluation technology. The new technology, known as the VR360 Diagnostic Cement Evaluation Tool, will have the capability of evaluating cement integrity even behind multiple casing strings. The tool will provide a full-3D cement map and will complement traditional ultrasonic measurements, which are highly sensitive to the cement bond between the cement and the inner casing wall.
Recent regulatory focus on deepwater wells initially stimulated the development of the technology, but as decommissioning and abandonment of mature wells grows in importance because of economic, regulatory, and environmental concerns, the tool’s potential in such settings spurred the effort to establish the agreement.
The goal of the joint industry project, which became effective in mid-December 2017, is to deliver a number of prototype tools for downhole deployment with a range of external diameters. The project is expected to last 3 years, during which time other oil companies may consider joining the project. The prototypes will be tested in both oil and gas wells.
The VR360 tool will be based upon a suite of X-ray technologies developed by Visuray known as the Downhole X-Ray Platform. Visuray’s first tool from the platform, the VR90 Downhole X-Ray Diagnostic Tool, has been used globally in well-inspection applications. The VR90 service uses an X-ray imaging technique that works in even opaque fluids. Its X-ray backscattering technology can work in any borehole fluid. X-ray forward-scattering is sensitive to the density of the material through which it passes. Because the X-ray source is orders of magnitude brighter than conventional radioisotopes, forward-scatter technology can be used to probe the well environment through multiple casings. The resulting reconstruction of the object’s surface can be displayed as both a 2D surface map and a 3D object with millimetric dimensional accuracy.