On Passing the Petroleum Professional Engineering Exam
Tuesday, April 27, 2021
Casing Design: 2021 #23
Design 7 in. production casing to be set in 11 lbm/gal mud in a vertical 15,000 ft well. Assume 10 lbm/gal pore pressure. Use three sections (minimum 2,000 ft each) based on pipe body performance properties. Design limits: 90M lbf overpull over buoyed casing weight...[see text]. What is the most cost-effective casing to use in the bottom of the hole?
A) 32 lbf, C-95
B) 29.0 lbf, C-110
C) 29.0 lbf, C-95
D) 26.0 lbf, C-95
Make sure you stay organized on this problem! Build a table of the needed information (provided in the problem or in the Reference on P41 and P67). Get be familiar with how the provided reference is organized; there is tons of data in a very small space and you need to be able to find and use it rapidly. Most importantly, the fomat is not overly similar to what you may be used to using. So here's our table:
This is a fairly tough problem. Remember, it's highly unlikely the design will be too complex, and your trick is to find the limiting factor as quickly as possible.
Why is the burst surface pressure 7780psi? also why do you not account for pressure inside casing while determining the collapse pressure and only account for the pore pressure pushing into the casing? and why are you using a 14000ft depth not 15000ft depth when determining the collapse pressure at TD?
Why is the burst surface pressure 7780psi? also why do you not account for pressure inside casing while determining the collapse pressure and only account for the pore pressure pushing into the casing? and why are you using a 14000ft depth not 15000ft depth when determining the collapse pressure at TD?
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