Two separate DST ball valves functioned using acoustics during a complex well test and abandonment.

17th December 2019

Following on from our last article where we described the successful use of our wirelessly controlled ball valve - FLOW-SURE BV - that was located beneath the packer, a second deep-water test has been conducted with the same client.

The string run was similar to the previous job in that the primary tester valve was located beneath the upper packer and the conventional ball/circulating valve located in the DST string was only used to facilitate pre-job circulations and well kill. The string was instrumented from top to bottom with Metrol’s PARAGON acoustics (OCULUS gauges, ORIGIN samplers, FLOW-SURE valves and mud line gauges). Once on depth the FLOW-SURE DV was used to spot a base oil cushion, functioning both the ball and sleeve in the DV to circulate fluid at the start of the test. One feature that became redundant was a time delay command programmed into the NIXUS gauges above the packer that was designed to mitigate the effects of top filling the string during RIH. The FLOW-SURE BV below the packer, if opened to prevent spillage on the drill floor, would have closed when a certain hydrostatic was seen by the NIXUS gauges. Later acoustic interrogation showed that the command had in fact been delivered, and the NIXUS tools were in a neutral state as the ball was already in the closed position and no action was required. The ability to remotely trigger valve movements in response to changing well conditions/parameters is a useful facility when designing a well test.

A plan to shut the lower FLOW-SURE BV beneath the packer was made to maximise pressure data retrieval at the moment of ball closure, and this all conducted as the submersible pump was functioning and the well was flowing. To achieve this outcome a time delay ball closure command was sent 12 hours prior to shut-in thus enabling maximum telemetry focus on data retrieval when the ball actually closed, seeing differential pressure above and below. It should be understood that the telemetry has a hybrid capability of using annulus pressure pulses instead of/or in addition to acoustics. It would have been possible, if required, to function the FLOW-SURE BV below the packer using a combination of annulus pressure pulses and acoustics to jump across the packer. Everything functioned perfectly with direct commands and this test in combination with all-encompassing pressure data collection demonstrated the superiority of Metrol’s expertise in the field of acoustic telemetry.