AE-May-2013-98-Pet-A4

pdf

School

Simon Fraser University *

*We aren’t endorsed by this school

Course

309

Subject

Mechanical Engineering

Date

Jan 9, 2024

Type

pdf

Pages

Uploaded by CaptainTree6267

National Exams May 2013 98-Pet-A4, Oil and Gas Well Drilling Completion 3 hours duration NOTES: 1. If doubt exists as to the interpretation of any question, the candidate is urged to submit with the answer paper, a clear statement of any assumptions made. 2. This is an OPEN BOOK EXAM. Any non-communicating calculator is permitted. 3. FOUR (4) questions constitute a complete exam paper. The first four questions as they appear in the answer book will be marked. 4. Each question is of equal value. Page 1 of 6

Page2of6 98-Pet-A4 May 2013 Question-1 Youare planning todrill awell with arigwhere 10lines arestrung between traveling block andcrown block. Maximum anticipated drilling depth is10,000 tt. The drill string consists of 4.5in.-20 Ibltt drill pipes and 7in.- 120 Ibltt drill collars. The drillstring design requires that thedrill collar length must be10 % ofthetotal drill string length. Company policy requires the useofasafety factor of2.0inallrigloaddesign calculations. Ignore the buoyancy effect. Determine the minimum drilling linesize (Le.smallest diameter possible) that can be.safely used withthis rig. NominalBreakingStrengths ofGalvanisedWire 0.59 0.72 1.04 l.42 79,600 1.85 103,400 2.34 130,000 2.89 159,800 3.5 192,000 4.16 228,000 4.88 264,000 5.67 306,000 6.5 348,000 7.39 396,000

Page 3 of 6 98-Pet-A4 May 2013 Question-2 A vertical well is being drilled currently at depth of 6500 ft. Other Relevant data: Drill Pipe: 5 in. x 4.276 in. Drill Collars: 7 in. x 3 in.- 900 ft. Casing: 9 5/8 in. x 9.00 in. set @ 6500 ft. vertical depth Mud density: 10 ppg Formation Pore pressure at current depth just below the bit : 3250 psi The Length of One Stand of drillpipe is = 90 ft a-) Determine the mud level drop if 15 stands of drillpipes are pulled out of the well without filling the well with mud. b-) What is the reduction in the bottomhole pressure (psi) corresponding mud level drop calculated in part a. c-) After pulling how many stands of drillpipes out of the well without filling the well with the mud, you would get a kick? (i.e. determine the number of driUpipe_~tands stacked at the rig floor)

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Page 4 of 6 98-Pet-A4 May 2013 Question-3 One of the two types of drilling bits has to be run into the hole at depth ~O,OOO ft., bit X or bit Y. Select the bit to drill from 10,000 ft downwards. The drilling rate equation is the same for both bits; (d O/dt);; 2 00 e -0.0002303"D Where; o ;; Depth, ft t ;; Time, hrs Bit lives and their prices are different and they are; Bit Type Bit Life, hrs Bit Cost, $ X 30 25000 Y 20 5000 The drilling rig operational cost is CR = $ 1000/hr Trip time function is tt = 0.001 D out (hrs) Connection time: 2 min/single pipe Length of 1 single pipe : 30 ft. Note: Tripping time to be considered using only D oul. D out : Depth where the bit is pulled out, ft.

Page 5 of 6 98-Pet-A4 May 2013 Question-4 You are assigned to a rig at the moment when drilling ahead is carried on. Company man wants to know the bottomhole pressure while drilling at 12,000 ft. Pumping rate with 11 ppg mud is 600 gpm. and the pump pressure is 3000 psi. You get information on drillstring composition and annular geometry and calculate the frictional pressure losses as follows: Inside the surface lines: 50 psi In the drillpipes: 800 psi In the Drill Collars: 600 psi In the drill collar annulus: 250 psi and In the drill pipe annulus: 150 psi Unfortunately nobody remembers the size of the nozzles installed in the bit. a-) Calculate the effective (circulating) bottomhole pressure (psi) exerted by the flowing mud. b-) If the formation fracture gradient is 12.5 Iblgal at 12,000 ft depth would you be able to continue drilling safely at this flowing bottomhole pressure safely? c-) (10 points) Determine the size of the nozzles (in 32nd of an inch), if there are 3-nozzles installed at the bit.

Page 6 of 6 98-Pet-A4 May 2013 Question-5 Your company wants to complete a well at 12,000 ft. using a 7 in. production casing. Relevant drill hole data are given below: Open Hole Diameter: 83/4 in. Mud Weight @ 12,000 ft. : 14.1 ppg Formation Pore Pressure Gradient @ 12,000 ft. : 13.5 ppg Formation Fracture Pressure Gradient@ 12,000 ft.: 15.5 ppg Formation Temperature @ 12,000 ft : 180 OF Normal Formation Pressure (Salt water) Gradient: 0.45 psi/ft. Prepare a casing program for this well. Your design should provide Grade, Weight, and length of the each casing section selected. Consider anticipated collapse burst and tensile load for your design. Assume that the Methane gas is going to be produced. Casing Design Factors Burst 1.1 Collapse 1.0 Tensile 1.6 Available Burst Collapse Body Joint Strength Casings Rating, psi Rating, psi Strength, [bf Buttress, Ibf ----------------- -------------- ------------- ---------------- ------------------- N-BO, 26 lb/ft 7,240 5,410 604,000 755,000 N-80, 32 Ibltt 10,040 10,320 745,000 889,000 P-110, 32 Iblft 13,800 13,220 1,025,000 1,111,000

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version