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PNG 450-Drilling Design Final Exam

Spring Semester 2010 (total 100 points)

1. (5 points) The highest collapse requirement for a casing string is at Top ofthe casing close to wellhead The middle (!) Bottom of the casing

2. (5 points) The highest tension requirement for a casing string is at (9 top of the casing close to wellhead

the middle bottom of the casing

/ 3. (5 points) The collapse strength of casing string will ___ with increasing tension: mcrease 0 decrease not change

4. (5 points) Cutter of drag bits can be made from: Steel

Gold

5. (5 points) Two main types of rotary drilling bits are Droa' b , h and Ra>l ,'"(5 c,,th:r. bit>

6. (5 points) Please classify a drill bit with IADC code of 647H: ______ _

7. (15 points) Calculated and de given: R = 25 ft/hr N=80RPM w = 30,000 lbf Da= 9 7/8 in Mud weight= 12lbm/gallon Normal pressure gradient of 0.5 psilft Overburden gradient= 1.0 psi/ft Poison ratio = 0.4 Depth= 16,000 ft

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Then based on the fi ure below, calculate formation ressure from Ben Eaton's method.

l

116,000

,

\ \ \ ____ , ' : \ . '\ .

Q 3

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8. (15 points) The same as question 7, then calculate the fracture gradient from Hubbert & Willis method and Ben Eaton method. Based on your calculations, recommend a drilling fluid system (mud weight) to drill through the formation at 16,000 ft.

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1 (\t-'S) 71? (5 1

'1-'

"":.\::_!.-{ 42 j_b 1 \ --- ,

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9. (25 points) A common problem of drilling oil and gas wells in deep water is the narrow window between the formation pore pressure and fracture pressure. Figure below shows a typical case from offshore Ghana (Hradecky and Postler, 2004).

Please identify how many casing runs you would recommend from 8,000 ft- 20, 000 ft for this well if an intermediate casing has been set from surface to 8,000 ft. And why? Is it safe to run 5.5", 23#/ft, PllO with long thread as production casing from surface (0 ft) all the way to 20,000 ft. No J 8v1 LJ / 5 _ cefll7) f> . . Of / l< .r a,

- Pore Pressure -Fracture Gradient n s (...,_.er-

114000

6 7 8 9 10 11 12 13 14 15 16 Equivalent Mud Welght,ppg

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10. (15 points) Design a directional well with the following restrictions: -..........,...L...r-L----Total horizontal departure = 3,500 ft True vertical depth (TVD) = 10,500 ft Depth to kickoff point (KOP) = 2,500 ft Rate of build ofhole angle = 2 deg/100 ft Type I well (build and hold) Calculate MD and maximum inclination angel.

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10. (20 points) Design a directional well #2 to start from surface location (A) and hit the reservoir target (B) under the lake as in the layout below.

Horizontal distance between A and B = 2,655 ft True vertical depth (TVD) = 11,500 ft Depth to kickoff point (KOP) = 2,400 ft Rate of build of hole angle = 3 deg/100 ft Azimuth Angle = S82E Type I well (build and hold)

Calculate MD to the end of build, total MD, and maximum inclination angel.

- --------

/ [Name: PNG 450-Drilling Design

Final Exam Spring Semester 2011

(Total 100 points)

Page 1 of 8

1. (5 points) To avoid buckling of drill strings, an engineer should design the string and make the neutral point fall inside

Kelly Drill pipes

0 Drill collars Drill bit Derrick

2. (5 points) The highest collapse requirement for a casing string is at Top ofthe casing close to wellhead The middle 6 Bottom of the casing

3. (5 points) The highest tension requirement for a casing string is at @ top of the casing close to wellhead

the middle / \ bottom of the (

4. (5 points) The collapse strength of casing string will ___ with increasing tension: mcrease G decrease not change

5. (5 points) Two main types of rotary drilling bits are 1'N C1dlvr b/ 1r

/ //

/ ;

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6. (5 points) What are the three main types of cementing process? Explain the purpose of each briefly.

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7. (25 points) In January 2011, a Range engineer tested the Marcellus shale formation and found a pore pressure gradient of0.83 psi/ft. We also know the formation depth is 8,000 ft, overburden is 1.1 psi/ft based on a density log and poison ratio is 0.35 based on a sonic log. Please calculate the fracture gradient from Hubbert & Willis method and Ben Eaton method. Based on your calculations, recommend a drilling fluid system (mud weight) to drill through this Marcellus formation.

The company plans to use 5.5", 23#/ft, N80 with long thread as production casing from surface all the way to 8,000 ft. Will the casing fail at 5,000 ft?

g e r. cl " F -- ( ? __ f ) (__E- \ 1-

D f) 1--i ) '0

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-----:..- \?. 2?)" ( 1,'-e !J -;JY-etfl"' C .. I' o.f:;c'-o,bl e P.?lj,?lh

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---

-------- ---

8. (15 points) Calculate d and de given: R = 30 ftlhr N=80RPM w = 30,00QJbf Ds = 9 7/8 in Mud weight = 10 Ibm/gallon Normal pressure gradient of 0.465 psi/ft Overburden gradient = 1.1 psi/ft Poison ratio = 0.4 Depth = 10,000 ft

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Then based on the figure below, calculate formation pressure from Eaton's method. Would you expect kicks if drillin sto s?

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110,000

1-155 1

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9. (10 points) A common problem of drilling oil and gas wells , in deep water is the narrow window between the formation pore pressure and fracture pressure. Figure below shows a typical case from offshore Ghana (Hradecky and Postler, 2004).

0.

Please identify how many casing you would recommend from 8,000 ft- 20, 000 ft if an intermediate casing has been set from surface to 8,000 ft. And why?

-Pore Pressure -Fracture Gradient

6 7 8 9 10 11 12 13 14 15 16 Equivalent Mud Weight,ppg

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10. (20 points) Design a directional well #2 to start from surface location (A) and hit the reservoir target (B) under the lake as in the layout below. '

Horizontal distance between A and B = 2,655 ft True vertical depth (TVD) = 11,500 ft Depth to kickoff point (KOP) ::;: 2,400 ft Rate of build of hole angle = 3 deg/100 ft Azimuth Angle = S82E Type I well (build and hold)

Calculate MD to the end of build, total MD, and maximum inclination angel.

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v\ ft....9ot)ertt -\0