Directional Survey Calculator

Calculator Inputs

Well Name

Length Units

Dogleg Reference Length

Vertical Section Azimuth (deg)

Decimal Places

Survey Stations

Enter one station per line: MD, Inclination, Azimuth

Example input format: 0,0,0, 100,4,35, 200,8,42

Example Data Table

Station	MD	Inclination	Azimuth
1	0	0	0
2	100	4	35
3	200	8	42
4	300	12	50
5	400	18	62
6	500	24	75

Formula Used

This calculator applies the minimum curvature method, a standard directional drilling technique for estimating the smoothest 3D path between two adjacent survey stations.

1) Course length
Course Length = MD₂ − MD₁

2) Dogleg angle
cos(Dogleg) = cos(I₂ − I₁) − sin(I₁) × sin(I₂) × [1 − cos(A₂ − A₁)]

3) Ratio factor
RF = 1 when Dogleg = 0
RF = (2 / Dogleg) × tan(Dogleg / 2) otherwise

4) Coordinate increments
ΔNorth = (Course / 2) × [sin(I₁)cos(A₁) + sin(I₂)cos(A₂)] × RF
ΔEast = (Course / 2) × [sin(I₁)sin(A₁) + sin(I₂)sin(A₂)] × RF
ΔTVD = (Course / 2) × [cos(I₁) + cos(I₂)] × RF

5) Accumulated position
North = ΣΔNorth, East = ΣΔEast, TVD = ΣΔTVD

6) Closure distance and azimuth
Closure = √(North² + East²)
Closure Azimuth = atan2(East, North)

7) Dogleg severity
DLS = (Dogleg in degrees / Course Length) × Reference Length

8) Vertical section
Vertical Section = North × cos(Target Azimuth) + East × sin(Target Azimuth)

How to Use This Calculator

Enter a well name for reporting clarity.
Select feet or meters for all measured depth results.
Set the dogleg reference length, such as 100 ft or 30 m.
Enter the vertical section azimuth used for project alignment.
Paste survey stations line by line as MD, inclination, azimuth.
Press Calculate Survey to compute trajectory coordinates and severity values.
Review the summary cards, data table, and Plotly charts.
Use CSV or PDF export when you need a report.

FAQs

1) What does a directional survey calculator do?

It converts measured depth, inclination, and azimuth into TVD, northing, easting, closure distance, closure azimuth, vertical section, and dogleg severity for each station.

2) Which method does this tool use?

It uses the minimum curvature method. This method usually gives smoother and more realistic wellbore paths than simple tangential or average angle approaches.

3) Why is dogleg severity important?

Dogleg severity highlights how sharply the well path changes over a reference length. Higher values can signal drillstring stress, torque issues, or completion concerns.

4) What is vertical section used for?

Vertical section projects the well path onto a selected azimuth plane. It helps teams compare planned and actual trajectory progress toward a target direction.

5) Can I use feet or meters?

Yes. The calculator lets you label results in feet or meters. Keep every input depth and reference length consistent with the chosen unit system.

6) What happens if two stations have the same measured depth?

The calculation becomes invalid because course length must be positive. This file checks that measured depth increases from one station to the next.

7) Why does the first station show zero course length and dogleg?

The first station is the starting reference point. Since there is no previous station, its course length, dogleg angle, and station deltas are zero.

8) What should I review after calculation?

Check final TVD, closure distance, closure azimuth, maximum inclination, maximum DLS, and plotted trajectory shape. These values quickly reveal path quality and target alignment.