Abstract

The objective of this paper is to discuss and outline how downhole pressure data conveyed through the wired drill pipe (WDP) telemetry system was used by the Snorre Expansion Project (SEP) team to drill pressure restrictive reservoirs safely and efficiently.

An original equipment manufacturers (OEM) WDP system was deployed on a ram rig for SEP late summer 2019 for the 24 well campaign. Drilling at six separate templates scattered between Snorre A and B, formation, well path and pressure regimes, differ significantly throughout the project. SEP divided its year into two phases: drilling during the Autumn and Winter seasons, and completion during Spring and Summer. To monitor and act on the changes in pressure, real-time along the string sensors were utilized through the WDP system. In conjunction with the newly developed prototype data while tripping (DWT) tool, constant 0.5 Hz pressure data was transferred real-time from downhole to the decision makers on the rig and onshore, both while drilling and tripping.

Allowing for continuous surveillance of the downhole condition proved crucial during the first reservoir section of the project that was drilled during a heavy Winter storm in January 2020. As well as gauging the effectiveness of the hole cleaning, the downhole impact of rig heave was also measured by the pressure sensors. The sensors showed that 1.5 to 2.0 m rig heave would result in up to ±20 bar fluctuation of the lowermost sensor, risking downhole pressure to go below the pore pressure of the formation. Acting on the real-time information, the rig halted drilling and pulled the string to the shoe, waiting out the weather. Swab pressures were measured while tripping and used to adjust the string speed, avoiding proximity to the pore pressure.

The drilling program was subsequently changed, postponing most challenging reservoir sections to the spring, thereby avoiding a similar situation or worse.

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