Problem 48. This is a standard problem just like in the Guidebook on 6 DTC 10. Math below. Note how much quicker using the "sc" chart for the tubing and casing is than doing the entire FL/EA calculation each time:
10,000 lbf(8103’ dp)1.5444E-07 (sc for dp) = 12.5”.
20.5” – 12.5” = 8”.
8”/[(10,000 lbf)1.1047E-07] (sc for tbg) = 7,243’ (A).
For calculating the first stretch for 8103 ft should we not be using the SC for 3.5in 12.8 lb/ft and for the 2nd stretch SC for 3.5 in 9.5 lb/ft?
ReplyDeleteThis may be a dumb question, my concept is not very clear on this one.
Using guide book and changing 3.5" tubing to 12.95 #/ft.
ReplyDeletePage 54: Stuck Pipe Method 1
First find stretch of DP - All of it is free, so Free pipe = 8103' (depth to top of fish)
Stretch = Free Pipe X Pull force / Free Point Constant
S = 8103 X (10) / (2500 * 2.59) = 12.5 inches
20.5 - 12.5 = 8" of stretch in the tubing.
Since the GB doesnt have 12.8#, lets use the 12.95# As
Freepipe = (8 x 2500 x 3.68)/10 = 7,360'
Length from top of fish to stuck point = 7,360
Stuck point depth = 15,463
Thank you for that Unknown. I have been out of town and behind on my comments. Thanks for helping out!
DeleteDavids calculation gives answer A) 7250; Stoves calculation (Stuck pipe Method 1) gives answer C) 7350 being closet to 7360. I solved the problem using Stuck Pipe Method 2 Page 54 PE Guidebook and also got fish length to stuck point 7360. I assume since we no longer have an access to stretch constants on the exam we have to use stuck pipe methods ?
ReplyDeleteDon't sweat this sort of thing; just make sure you know what you have in the Reference Guide, but be prepared for the exam to give you any and all needed equations. It's better to just learn the material and beware of any angle the tester's choose. The test is clearly in a transition between open book and the Reference Guide and so may just give you some needed equations here or there. All you can do is practice the material in the SPE resources.
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