Overview:
- Continuous surveys are repeatable and accurate
- Combining continuous with static surveys = ISCWSA error model
- Survey intervals matter – 3m
- Continuous surveys are essential for TVD accuracy
- There is value in continuous surveys
Background
- Continuous surveys have been available for a long time
- Lesso et al., 2001, IADC/SPE 67752 - paper on tendency analysis
- Stockhausen and Lesso 2003, IADC/SPE 67752 – paper on TVD Errors
associated with survey frequency
- Waiting on a Solution – collecting additional data examples – beta
testing software solutions
- Assumption of minimum curvature
- Identified sources of TVD/positional errors associated with long survey
intervals
─ Pattern Slide/Rotate drilling practices in build/drop/turn sections
─ Short slides during tangent sections
─ Changing modes between survey stations with Rotary Steerable Systems
─ Bha reaction to tight streaks, boulders, or nodules
─ Geologist interventions
Steering decisions
Control ROP to acquire logging data
─ BHA auto control with some RSS
....
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Combining Static and Continuous Surveys
Ross Lowdon (SLB) and Ed Stockhausen (CVX)