Dogleg Severity Calculation based on Radius of Curvature Method

Dogleg severity (DLS) is a normalized estimation, normally described in degrees per 100 feet or degree per 30 meters, of the overall well bore curvature between two consecutive directional surveys. Regarding a planned well path, dogleg severity may be synonymous about build and/or turn. The following formula provides dogleg severity in degrees/100 ft  based on the Radius of Curvature Method.

directional survey photo

Dogleg severity (DLS) = {cos-1 [(cos I1 x cos I2) + (sin I1 x sin I2) x cos (Az2 – Az1)]} x (100 ÷ MD)


DLS = dogleg severity in degrees/l00 ft

MD = Measured Depth between survey points in ft

I1 = Inclination (angle) at upper survey in degrees

I2 = Inclination (angle) at lower in degrees

Az1= Azimuth direction at upper survey

Az2 = Azimuth direction at lower survey

Example for dogleg severity based on Radius of Curvature Method

Survey 1

Depth = 7500 ft

Inclination = 45 degree (I1)

Azimuth = 130degree (Az1)

Survey 2

Depth = 7595 ft

Inclination = 52 degree (I2)

Azimuth = 139 degree (Az2)

Dogleg severity (DLS) = {cos-1 [(cos 45 x cos 52) + (sin 45 x sin 52) x cos (139 – 130)]} x (100 ÷ 95)

Dogleg severity (DLS) =  10.22 degree/100 ft

Please find the Excel sheet used to calculate dogleg severity based on Radius of Curvature Method.

Ref book: Drilling Formula Book Formulas and Calculations for Drilling, Production and Workover, Second Edition

Directional Drilling Books

Related Post

Pressure Required to Break Circulation in Annulus From the previous post, we learn about how to determine break circulating pressure inside drill string. This post we will learn about how to calculate...
Applications of Directional Drilling in Oil and Ga... Directional drilling is an advance drilling technique which can deviate wellbore to the planned trajectory in order to reach the reservoir targets. No...
Determine Optimum Drilling Flow Rate for Basic Sys... From the previous post (total pressure loss excluding the bit), we know the equation (shown below)     We can solve the equatio...
Determine surge and swab pressure method 2 Calcula... This section will show to how to use the formula from the previous topic, surge and swab pressure calculation 2nd method , to determine surge and swab...
Share the joy

About DrillingFormulas.Com

Working in the oil field and loving to share knowledge.
Tagged , . Bookmark the permalink.

3 Responses to Dogleg Severity Calculation based on Radius of Curvature Method

  1. cna training says:

    found your site on today and really liked it.. i bookmarked it and will be back to check it out some more later

  2. Slickliner says:

    and this is the same tangential method. Well this is the correct Tangential Method. It just a matter of simplified Trigonometric Law. cos (B-A) = sinA*sinB + cosA*cosB.
    Radius Curvature Method is a way complicated than showed above.

Leave a Reply

Your email address will not be published. Required fields are marked *