Pushing the Envelope of Casing and Cement Inspection: Logging Two Casing Sizes Simultaneously and Setting a Cement Plug in a Single Run

Casing and cement inspection logging is critical for many well operations and is also, in many cases, a regulatory requirement. These measurements have traditionally been acquired on wireline. Recent developments have shown that ultrasonic pulse-echo measurements can now be acquired on drillpipe-conveyed tools. This has opened up a window of opportunity for significant time savings by logging in parallel with existing rig operations and to undergo operations that are impossible with wireline-conveyed tools. A North Sea operator wished to maximize operational efficiency by logging the material in the annulus on both a 13.375-in. casing and a 9.625-in. liner simultaneously. Additionally, a cement plug was set, all in the same operational run. To achieve this, two drillpipe-conveyed tools were run in memory mode and spaced by several hundreds of meters, such that the top tool, which needed larger centralization, could not run into the top of the 9.625-in. liner. These tools both had three circumferentially arranged ultrasonic transducers, with the top tool centralized for the 13.375-in. casing and the bottom tool for the 9.625-in. liner. The relevant sections of both the 13.375-in. casing and the 9.625-in. liner could then be evaluated in a single logging run. By rotating the drillpipe and pumping, both relevant sections of the two sizes of well barrier acquired fully azimuthal data of their respective casing and liner. Subsequent to the logging, a cement plug was then set as the tools have a full through bore, allowing passage of cement through the tools. The results were analyzed through both rigsite processing and full waveform processing to evaluate the material outside the casing in the annular space for cement analysis and barrier identification. Each individual transducer (three on each tool) was evaluated separately and then compared for additional quality control and interpretation. The data acquired were entirely sufficient to make an informed decision for the rest of the well operations. This run, combining dual-spaced tools run on drillpipe and cementing through the same string, is the first instance of this type of logging ever recorded and significantly impacted rig efficiency and savings. Additionally, it was the first time logging a new cement type. Traditionally, this would have been acquired with two separate dedicated logging runs. Several other wells are now planned to operate in this unique way, pushing the envelope on how and when we acquire this critical well information.