Motor Yield / DLN — Slide & Rotate Calculator
Landing Targets & Survey Yield Check
Enter landing targets, then two accepted surveys and the slide footage between them. Verify the effective slide build and optionally apply a simplified TVD-based DLN to the existing slide/rotate calculator.
Landing DLN is a constant-build TVD estimate, not an independently verified steering need. It can differ substantially from the actual directional plan.
Estimated slide build yield = (observed inclination build − rotary build × rotation fraction) ÷ slide fraction. Assumes stable rotary tendency and predominantly high-side sliding. Not a measured full 3D motor yield. No estimate is possible with zero slide footage. TVD is recorded for reference, not used to infer yield.
Plan the interval
Required slide / rotate
Blue = slide; orange = rotate. This is a theoretical inclination-only average, not a stand steering instruction.
3D Landing Direction Check
Uses the current survey and target inclination/azimuth entered above. The toolface shown is an estimated initial steering direction toward the target inclination and azimuth, not a verified toolface to hold for an entire stand.
Turn Needed is the shortest azimuth correction from the current survey to the target, not a turn rate or slide recommendation. This check does not calculate a 3D path or toolface schedule. This check does not replace the inclination-only DLN input above. At low inclination, gravity toolface may be unreliable.
What if they rotate more?
Enter the footage you want to rotate on the interval to estimate the resulting inclination build under the same assumed rates.
Estimate = (slide ft × slide yield + rotate ft × rotary tendency) / 100. It is not a measured survey result.
Saved calculations
Saved locally in this browser. Export records before clearing browser data or changing devices.
What the red flags mean
RED: required build is outside the assumed sliding/rotary capability, or the entered what-if rotation footage predicts a build shortfall. AMBER: little or no rotation margin, or the assumed rates are too similar to solve uniquely. GREEN: the mathematical mix is possible under the entered assumptions—not proof the well will land.
*Critical limitation: Here “DLN” means required inclination build, not full 3D dogleg severity. For azimuth changes, non-aligned toolface, RSS steering, varying motor response, or a tight TVD/position target, this weighted-average formula can be misleading. Validate the current survey, 3D projection, BHA response and operator limits. Never use this tool alone to authorize drilling decisions.