Dogleg severity between two survey stations
Dogleg angle and severity (°/10 m, °/30 m, °/100 ft), and the changes in vertical depth, north and east between two survey stations, by the minimum curvature method.
cos β = cos I_1 · cos I_2 + sin I_1 · sin I_2 · cos(A_2 − A_1)RF = (2 / β) · tan(β / 2), β in radΔTVD = ΔL/2 · (cos I_1 + cos I_2) · RFΔN = ΔL/2 · (sin I_1 · cos A_1 + sin I_2 · cos A_2) · RFΔE = ΔL/2 · (sin I_1 · sin A_1 + sin I_2 · sin A_2) · RFDLS = β · 30 m / ΔLBoth azimuths must refer to the same north (true, magnetic or grid); crossing 0°/360° is handled. Russian-language practice gives the severity per 10 m, international practice per 30 m and per 100 ft (100 ft = 30.48 m).
Source: Minimum curvature method: API Bulletin D20 (1985); Bourgeois et al., Applied Drilling Engineering (SPE, 1986), ch. 8
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
Unit converter for this formulaLength
- m1
- cm100
- mm1,000
- km0.001
- ft3.28084
- in39.3701
- 1/32 in1,259.84
- 1/64 in2,519.69
- mile0.000621371
- DLS — The same per 10 m–°/10 m
- DLS — The same per 100 ft–°/100 ft
- β — Dogleg angle–°
- ΔTVD — Change in true vertical depth–
- ΔN — Change in northing–
- ΔE — Change in easting–
- ΔH — Horizontal displacement over the interval–
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.