Overview:
- Minimum curvature Trajectory Model could not fit the data
- High Magnetic Ranging Uncertainty because the trajectory is not adequate.
- The Step-by-step trajectory has allowed better fitting of the measured data
- If Minimum curvature Trajectory was kept, Side-track or reduced spacing ranging would have been required
The Problem
- In SPE paper 67616 , The minimum curvature is considered as the recommended, usual and worldwide accepted as the common method for wellbore reconstruction
- The MWD Error Model and Gyro Error Model are based on the minimum curvature and the sources of errors listed lead to EOU around the wellbore trajectory
- There is no error source considered for the position of the wellbore trajectory itself, meaning there is no error source corresponding to the reconstruction method of wellbore trajectory
- EOU are therefore constructed on a “minimum curvature trajectory” which could be unrealistic
- The emergence of continuous survey has shown that the real wellbore path trajectory could be largely different from a minimum curvature reconstruction based on spaced survey, in particular while drilling with Motors or RSS system
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DrillScan