Schlumberger

Case Study: Tractored One-Run Gyroscope and Production Logging in North Sea Horizontal Sidetrack

Combined gyroscope and PS Platform production services platform logging on tractor confirms placement and profiles fluids

Challenge: Confirm orientation of 500-ft sidetrack drilled at the toe of a North Sea horizontal well when the operator was forced to deviate from the planned trajectory.

Solution: To avoid the additional intervention of a trajectory survey, use the MaxTRAC downhole wireline tractor system for one-trip logging by the PS Platform production services platform incorporating a gyroscope data tool.

Result: Confirmed that the well trajectory stayed in the reservoir and acquired critical reservoir fluids data in a single descent.

Unknown sidetrack trajectory

A North Sea operator drilling a horizontal well had to sidetrack the last 500 ft from the planned trajectory as a result of drilling-related conditions at the toe of the well. A trajectory survey was needed to determine well orientation and position in the reservoir, but the operator wanted to avoid additional intervention in the well.

Tractor-conveyed gyroscope data tool

To provide the missing trajectory data, a gyroscope data tool was incorporated in the PS Platform production services platform along with an RST reservoir saturation tool. The gyroscope data tool simultaneously acquires high-accuracy survey data while production logging. Its two components are a Gyrodata Inc. Production Gyro Data Sonde (PGDS) to acquire well trajectory data and a cartridge for communication and power interface to the logging string.

By deploying the logging string with a MaxTRAC downhole wireline tractor system, the operator would minimize intervention to a single run while avoiding the expense and complexity of running tools on drillpipe or coiled tubing.

One-run trajectory and production logging

Gyroscope data was recorded from the seabed to the bottom of the well. After RST tool measurements were acquired across the reservoir section, another gyroscope data pass was recorded from the bottom of the well to the seabed. Using the MaxTRAC tractor to convey the one-run simultaneous trajectory and production logging delivered significant rig-time savings.


Download: Tractored One-Run Gyroscope and Production Logging in North Sea Horizontal Sidetrack (0.64 MB PDF)

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One-Run Confirmation of Trajectory and Fluids

Gyroscope survey confirms sidetrack path in reservoir.
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