Verification and testing of a newly installed wellbore barrier, in older assets has proven to be challenging. Even more so when the well has structural issues, indemnities or weak spots in the barrier envelope, or weakend well construction that limits the possibility to acheive a positive pressure verification of the barrier with an applied surface pressure versus the reservoir pressure.
A suitable location with necessary support and strength should be located in the well. If installing a mechanical barrier in means of a bridge plug as the primary barrier, we will monitor the installation forces in the anchoring and sealing sequence. This individual signature will be verified towards a nominal base line signature of a ISO approved test and a library of thousands of collected installation profiles. Any abnormality can trigger a release and relocating of the barrier. A second verification barrier will then be installed close above the primary barrier and installation sequence will be verified the same way as the primary barrier. When both installation signatures are accounted for we can pressure test the installed barriers. This can be done with a pressure manipulation tool, where we introduce a calculated predetermined pressure drop between the installed primary barrier and the verification barrier above. By monitoring this pressure alteration vs. the pressure above the verification barrier, we can determine if we have a verified primary and verification barrier.
The Primary Barrier is verified in the direction of flow (negative pressure test). And verification barrier as the secondary barrier is verified with a positive pressure test. If a dual barrier is requested you can leave the verification barrier as secondary barrier or pull to re-use.
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