Directional Survey Calculator

Calculation Method

Minimum Curvature

Most accurate. Industry standard for wellbore surveys.

Radius of Curvature

Assumes constant build/turn rates between stations.

Balanced Tangential

Average of tangential values at each station.

Tangential

Uses lower station only. Least accurate.

Average Angle

Uses arithmetic average of inc and azi between stations.

Survey Stations

#	MD (m)	INC (°)	AZI (°)

Well Parameters

Well / Borehole Name

MD Units

Surface N (m)

Surface E (m)

KB Elevation (m)

Magnetic Declination (°) + East / − West. Applied to all azimuths.

DLS Threshold

Warning above (°/30m)

°/30m

Critical above (°/30m)

°/30m

ℹ Enter at least 2 stations (MD, Inc, Azi) then click Calculate.

Well

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Method

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Stations

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Total MD

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Max Inc

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Max DLS

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Survey Results

← Scroll horizontally for all columns →

#	MD (m)	INC (°)	AZI (°)	TVD (m)	ΔN (m)	ΔE (m)	N (m)	E (m)	VS (m)	DLS (°/30m)	BUR (°/30m)	TUR (°/30m)

Plan Views

Plan View (N–E)

Vertical Section (VS–TVD)

East vs TVD

Dogleg Severity Profile

Minimum Curvature (MC)

The industry-standard method. Uses a ratio factor RF derived from the dogleg angle to calculate a smooth arc between successive stations.

// Dogleg angle (β) — radians β = arccos(cos(I₁)·cos(I₂) + sin(I₁)·sin(I₂)·cos(A₂−A₁)) // Ratio factor RF = (2/β)·tan(β/2) // when β = 0, RF = 1 // Increments ΔTVD = (ΔMD/2)·(cos I₁ + cos I₂)·RF ΔN = (ΔMD/2)·(sin I₁·cos A₁ + sin I₂·cos A₂)·RF ΔE = (ΔMD/2)·(sin I₁·sin A₁ + sin I₂·sin A₂)·RF // Dogleg Severity (°/30 m) DLS = β·(180/π)·(30/ΔMD)

Radius of Curvature (RC)

Assumes constant build and turn rates. Divides by the difference in inclination/azimuth when non-zero.

// When ΔI ≠ 0 and ΔA ≠ 0 ΔTVD = ΔMD·(sin I₂ − sin I₁)/ΔI ΔN = ΔMD·(cos A₁ − cos A₂)·(cos I₁ − cos I₂)/(ΔI·ΔA) ΔE = ΔMD·(sin A₂ − sin A₁)·(cos I₁ − cos I₂)/(ΔI·ΔA)

Alerts Reference

✓DLS within normal limits — well trajectory is smooth.

⚠DLS exceeds warning threshold — monitor casing wear.

✕DLS exceeds critical limit — risk of drill string fatigue.

Balanced Tangential (BT)

ΔTVD = (ΔMD/2)·(cos I₁ + cos I₂) ΔN = (ΔMD/2)·(sin I₁·cos A₁ + sin I₂·cos A₂) ΔE = (ΔMD/2)·(sin I₁·sin A₁ + sin I₂·sin A₂)

Tangential (TA)

ΔTVD = ΔMD·cos I₂ ΔN = ΔMD·sin I₂·cos A₂ ΔE = ΔMD·sin I₂·sin A₂

Average Angle (AA)

Iavg = (I₁ + I₂)/2 Aavg = (A₁ + A₂)/2 ΔTVD = ΔMD·cos Iavg ΔN = ΔMD·sin Iavg·cos Aavg ΔE = ΔMD·sin Iavg·sin Aavg

Terminology

Term	Description
MD	Measured Depth along borehole
INC	Inclination from vertical (°)
AZI	Azimuth from North 0–360 (°)
TVD	True Vertical Depth
N/E	North/East departure from surface
VS	Vertical Section in closure direction
DLS	Dogleg Severity (°/30m)
BUR	Build-Up Rate component
TUR	Turn Rate component