The challenge
- →Confirm safe pass-by / relative position between deep offshore wells (closest approach ~30 m).
- →Ranging had to run on a third-party MWD sensor, not Gunnar's own tool.
- →A weak target signal (~27 nT at 30 m) sat right at the sensor's noise floor.
Our solution
Gunnar characterized the third-party sensor's noise floor from downhole data, subtracting the Earth's field to expose the interference signal, then assessed 18 passive magnetic ranging surveys to resolve the pass-by. Delivered jointly with a gyro-survey partner.
Pass-by confirmed at ~30 m, 18 surveys, zero NPT
The result
~30 m
closest approach, resolved on a third-party MWD sensor
- ·18 PMR surveys assessed across the run, no delays or NPT
- ·Characterized the third-party MWD sensor noise floor via Earth-field subtraction
- ·Resolved the ~27 nT pass-by signal at ~30 m against a ~13–46 nT noise floor
- ·Confirmed relative position / safe pass-by on the offshore twin
Ranging
PMR
Deployment
Wireline / MWD (PMR)
Re-entry
No
Location
Offshore Malaysia
Year
2021