# Burst (Internal Yield Pressure) Property of Tubular

Burst is a condition where internal pressure exceeds pressure loading. Burst can happen in several situations, such as well control, pressure test casing/tubing, pumping operation, etc.

Figure 1 – Burst Pressure Diagram

Minimum burst rating pressure (internal yield pressure) can be calculated by the following equation.

Where;

PB – Minimum internal yield pressure (psi)

Yp – Minimum yield strength (psi)

t – Nominal wall thickness (in)

D -Nominal outside diameter of the pipe (in)

This image shows when tubular is exposed to a differential internal pressure over its burst pressure rating.

(Ref: http://gekengineering.com/Downloads/Free_Downloads/Casing_Design_Hand_Calculation_Design_Example.pdf)

Some interesting points about burst pressure

• This equation (Barlow’s Equation) determines the internal pressure at which the tangential stress at the inner wall of the tubular reaches the minimum yield strength (YS) of the pipe.
• Factor 0.875 in the equation represents allowance of manufacturing tolerance of -12.5% on wall thickness specified in API 5CT.
• Burst will be occurred when stress is over ultimate tensile strength of material. However, the equation uses the Yield Stress of material, which is a conservative assumption.

Example: Calculate the tensile strength of the following pipe.

4-1/2” casing, weight 9.5 ppf,  grade J-55

Pipe ID = 4.09”

Wall thickness 0.205 “

Yp = 55,000 psi

PB = 4,385 psi

This figure can be seen in the API specification.

Figure 2 – API Burst Rating Pressure

Download the API tubular data sheet here – https://www.drillingformulas.com/oilfield-casing-data-sheet-free-download/

References

Jonathan Bellarby, 2009. Well Completion Design, Volume 56 (Developments in Petroleum Science). 1 Edition. Elsevier Science.

Wan Renpu, 2011. Advanced Well Completion Engineering, Third Edition. 3 Edition. Gulf Professional Publishing.

Ted G. Byrom, 2014. Casing and Liners for Drilling and Completion, Second Edition: Design and Application (Gulf Drilling Guides). 2 Edition. Gulf Professional Publishing.

PEH:Casing Design. 2015. Casing Design. [ONLINE] Available at: http://petrowiki.org/PEH%3ACasing_Design. [Accessed 1 June 2016].

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