XACT service facilitated riser-less integrity test, enabled slot recovery
A customer needed to re-evaluate a previously abandoned well in deepwater Gulf of Mexico. The slot had been abandoned at the 20-in. casing shoe due to an extremely narrow pore pressure fracture gradient window and the associated risks of weakening the integrity of adjacent wells. The area had a history of shallow hazards and shallow water flow conditions, causing significant problems in the past. To examine the feasibility of recovering the slot required undertaking a formation integrity test. The time and cost of purchasing a riser, installing a blowout preventer (BOP), and the relevant rig time made this choice uneconomical with conventional technology and current economic conditions.
To undertake the operation without installing a riser required real-time measurement below and above a packer, the ability to transmit data through a packer without hard wiring, and back to the surface in low and no flow conditions. Full through bore capability was also a requirement for wireline evaluation, as well as the potential to cement through the string, and the ability to mechanically activate circulation subs by dropping balls and bars.
The operator contacted Baker Hughes, a GE company (BHGE), and decided to conduct a riser-less operation with the XACT™ downhole acoustic telemetry service. Integrated measurement and acoustic telemetry nodes were positioned above and below a packer. Internal pipe and annular pressures were used to conduct the belowthe- packer formation integrity test, and to monitor the operation of the circulating subs and the activation of the packer. Downhole weight was used to check the effectiveness and correct the setting of the packer. Acoustic signals sent through the wall of the regular rig drillpipe transmitted data back to the surface in real time, irrespective of flow conditions.
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