Collapse strength, tensile strength, 13 3/8" API casing
Collapse strength, tensile strength, 13 3/8" API casing
(OP)
I would like to calculate the collapse strength and tensile strength of an API casing which has been perforated over 16% of it's surface as per the following:
API 13 3/8", K-55, 54.5 PPF, Range 3, BTC. Perforated with 5/8" holes uniformly positioned across the length and circumference of the casing. See attached drawing.
API 13 3/8", K-55, 54.5 PPF, Range 3, BTC. Perforated with 5/8" holes uniformly positioned across the length and circumference of the casing. See attached drawing.





RE: Collapse strength, tensile strength, 13 3/8" API casing
First off, tensile strength is a material property that will not change from loss of material.
Here is a tip, I consider use of ASME Boiler and Pressure Vessel Code, Section VIII, Div 1 for guidance and use one of the design rules for openings in a shell (HINT UG-53).
Second tip, the formula for determining minimum thickness requires information such as hole pitch and spacing. The thickness for the casing will be determined based on area loss.
RE: Collapse strength, tensile strength, 13 3/8" API casing
thanks for your reply. I have to try and keep it as simple as possible. I've had the following advise from a German friend who has worked in the oil screen business and is now retired. Unfortunately he's on a motorbike tour of Europe so his access to information is limited. Here's what he had to say:
Take API collapse value for equivalent carbon steel casing from standard 5B/5CT. Reduce by 20% due to perforation of base pipe. Screen jacket will not be considered!
For tensile same applies. Take value from API list and reduce by 20%
Would you or anyone else have access to these values of collapse resistance and tensile strength for API seamless casings 13 3/8", 54.5 PPF in K/J-55 material? I've got the 5B and 5CT but these values are not mentioned.