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INPUTS

Lease Henderson Ranch

Well Name #2Date 8/10/2010

Casing Size 13.375 IN. 140.5004

Casing Weight 68.0 #/FT 19.4452 1.077326

Casing ID 12.415 IN. 121.0552

Casing Setting Depth 3,200 FT

TD of Next Section 8,400 FT

Mud Weight Run In 9.1 PPG

Heaviest MW below 11.5 PPG

Overpull When Set 0

Lead Cement Weight 12.5 PPG

Lead Cement Height 2,450 FT

Tail Cement Weight 15.6 PPG

Tail Cement Height 750 FT

oF Surface Temp 75

oF @ Casing Point 120

oF @ TD of Heavier MW 185

oF @ TOC (initially) 75

oF @ TOC (final) 75.0

TOP OF CEMENT - FT

EQ CEMENTED HYDROSTATIC

 AT CASING DEPTH 13.2 PPG

FORCE DUE TO CHANGE IN 75 75.0

TEMPERATURE - LBF 0.0

EQ LENGTH CHANGE DUE TO

CHANGE IN TEMP 0.0 IN.

BALLOONING FORCE DUE TO 0

HEAVIER MUD WT - LBF

EQ LENGTH CHANGE DUE TO

BALLOONING 0.0 IN.

RUNNING TENSION

3200 -29445

0 188155

-50000

Henders

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CEMENTED TENSION

3200 -125921 0 -29444.7

0 91679 0 188155.3

0 91679

0 91679

 AXIAL LOAD W/ OVERPULL, TEMP & BALLOONING

0 91679

0 91679

CEMENTED STABILIZING FORCES

3200 -125921

0 0

0 0

WEIGHTED-UP STABILIZING FORCES

0 0 -91679.3

0 0

ADDITIONAL TENSION (OVERPULL) NEEDED

-  LBF

 Additional T -91679

0

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13.375 IN.

0

500

1000

1500

2000

2500

3000

3500

50000

Casing Tension/Buckling Plot

RUNNICEME

 AXIALCEMEWEIGTop of 

on Ranch #2

0 A -91679

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150000

ING TENSIONNTED TENSIONLOAD W/ OVERPULL, TEMP & BALLOONINGNTED STABILIZING FORCESTED-UP STABILIZING FORCES

Cement

Overpull When Set 0

-91679 Additional Tension to Avoid Buckling

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Bu ck l ing & Wel lhead L oad A f te r Cement ing 

CASING PROPERTIES

CASING OD (IN.) 13.375 EXTERNAL END AREA (SQ.IN.) 140.50

CASING ID (IN.) 12.415 INTERNAL END AREA (SQ.IN.) 121.06

CASING WT./FT 68 STEEL END AREA (SQ.IN.) 19.45

CASING LENGTH (FT) 3200 Tensile Strength Casing

Wellhead Loads after Cementing Buckled? Yes -68

INITIAL CONDITIONS (While cement sets)

Wellhead Load (=Tension at surface)

T; Mlbs

Mud wt. inside (MWi) 9.1 ppg +wt. of pipe +wpf*L/1000 218

Mud wt outside (MWo) 9.1 ppg +wt mud inside +0.052MWi Ai L/1000 183

Pressure inside (Pi) 0 psi -wt cement -0.052MWc Ao(L-TOC)/1000 -292

Pressure outside (Po) 0 psi -wt. mud outside -0.052MWo Ao TOC/1000 0

 Avg cement dens (MWc) 12.5 ppg + pressure-area + (PiAi - PoAo)/1000 0

Top of cement (TOC) 0 ft + Pickup + Pickup 0

Pickup is + 0 Mlb (Slackoff is -)

Initial Wellhead Load 109

FINAL CONDITIONS

Mud wt inside 11.5 ppg -68

Mud wt outside 9.1 ppg Yes Drilling

Pressure inside 0 psi

Pressure outside 0 psi

Changes (final - initial) Formulae for dT dT; Mlbs

dMWi 2.4 ppg + µ(0.052dMWi)Ai(TOC)/1000 0

dMWo 0 ppg - µ(0.052dMWo)Ao(TOC)/1000 0

dPi 0 psi +2µ dPi Ai/1000 0

dPo 0 psi -2µ dPo Ao/1000 0

dTemp 44 °F 94 -AE¦(dTemp)/1000 -177

Total dT -177

Final Wellhead Load -68

Buckling of Casing after Cementing

INITIAL CONDITIONS (While cement sets)

Initial Effective tension at TOC Teff;Mlbs

Mud wt. inside (MWi) 9.1 ppg +pipe below TOC +wpf(L-TOC)/1000 218

Mud wt outside (MWo) 9.1 ppg +wt mud inside +0.052MWi Ai(L-TOC)/1000 183

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Pressure inside (Pi) 0 psi -wt cement -0.052MWc Ao(L-TOC)/1000 -292

Pressure outside (Po) 0 psi +Pickup +Pickup 0

 Avg. cement dens (MWc) 12.5 ppg

Top of cement (TOC) 0 ft Initial Teff at TOC 109

Pickup 0 Mlb (Slackoff is -)

FINAL CONDITIONS

Mud wt inside 11.5 ppg

Mud wt outside 9.1 ppg

Pressure inside 0 psi

Pressure outside 0 psi

Changes (final - initial) Formula for dTeff  dTeff;Mlbs

dMWi 2.4 ppg -(1-µ)(0.052dMWi)Ai(TOC)/1000 0

dMWo 0 ppg +(1-µ)(0.052dMWo)Ao(TOC)/1000 0

dPi 0 psi -(1-2µ)dPi Ai/1000 0

dPo 0 psi +(1-2µ)dPo Ao/1000 0

dTemp 44 °F -AE¦(dTemp)/1000 -177

If Teff < 0, assume casing is buckled. Total dTeff   -177

Final Teff at TOC -68

Buckled?  Yes

TEMPERATURE CALCULATIONS

(For drilling strings )

Static Temperatures

Surface (Ts) 75 °F y = TOC/TVD 0.00

Bottom hole (Tb) 185 °F k = 0.4+0.306y+0.029y^2-0.125y^3 0.400

TVD next hole section 8400 ft Init. avg temp: Ts + (Tb-Ts)y/2 75

Final avg temp; °F: Ts+(Tb-Ts)k 119Must be entered above;°F: dTemp 44

(For completion strings )

Surface Injection (Tsi) 80 °F y = TOC/TVD 0.00

 At perforations (Tp) 195 °F For big jobs f = 3 Little jobs f = 2 3

TVD Perforations 9321 ft Final avg temp; °F: Tsi+(Tp-Tsi)y/f  80

Must be entered above; °F: dTemp 5

E = 30,000,000 psi; Poisson's ratio µ = 0.3; Coefficient of thermal expansion ¦ = 6.9E-6 / °F

PURPOSE: Computes stresses, loads, and buckling in casing after cementing

COMPUTATIONS:

1. Buckling in intermediate and completion casings

2. Wellhead loads in intermediate and completion casings

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= FL/EA ;note that we can cancel the length L from each side of the equation, and then cr

= F/A , however, F/A is stress and we can finally write:

; The thermal stress which develops if a structure or member is completely constrained (n

3713 14 0.78626 26.4 0

3800 14 0.78626 26.4 1805.881

3900 14 0.78626 26.4 3881.606

4000 14 0.78626 26.4 5957.331

4100 14 0.78626 26.4 8033.056

4200 14 0.78626 26.4 10108.78

4300 14 0.78626 26.4 12184.51

4400 14 0.78626 26.4 14260.23

4500 14 0.78626 26.4 16335.96

4600 14 0.78626 26.4 18411.68

4700 14 0.78626 26.4 20487.41

4800 14 0.78626 26.4 22563.13

4900 14 0.78626 26.4 24638.86

5000 14 0.78626 26.4 26714.58

109 5100 14 0.78626 26.4 28790.31

5200 14 0.78626 26.4 30866.03

5300 14 0.78626 26.4 32941.76

5400 14 0.78626 26.4 35017.48

5500 14 0.78626 26.4 37093.21

5600 14 0.78626 26.4 39168.93

5700 14 0.78626 26.4 41244.66

5800 14 0.78626 26.4 43320.38

5900 14 0.78626 26.4 45396.11

6000 14 0.78626 26.4 47471.84

6100 14 0.78626 26.4 49547.56

6200 14 0.78626 26.4 51623.29

6300 14 0.78626 26.4 53699.01

392224 6400 14 0.78626 26.4 55774.74

6500 14 0.78626 26.4 57850.46

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oss multiply by E, arriving at:

ot allowed to move at all) is the product of the coefficient of linear expansion and the tem

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erature change and Young's modulus for the material.