HDD Calculation

PROJECT: Prepared by: Checked by: HORIZONTAL DIRECTIONAL DRILLING CALCULATION

Ldepth

Lcrossing

Rarc1

Rarc2

 in

 

20

600

720

720

10

10

L1

Larc1

L2

Larc2

L3

Ltot

52.18

125.66

247.17

125.66

52.18

602.86

DESIGN DATA Pipeline Diameter

D

thickness (min)

t

36 inch

914.4 mm

15.9 mm

18.3 mm (D/t should be < 60) 0.626 in

Pipeline Material Grade

X60

SMYS of Pipeline

S

415 Mpa

Steel Density

s

7850 kg/m

Water Density

w

1000 kg/m3

60190.77 lb/in2 3

Soil Density

1800 kg/m3

112.37 lb/ft3

Mud Density

1437.8 kg/m3

89.76 lb/ft3

Drilling Fluid Density

d

Soil friction Angle



30 degree

Poisson Ratio for Steel



0.3

Modulus of Elasticity

E

207000 Mpa

Installation Temperature

T1

13 degC

Operating Temperature

T2

65 degC

Steel Coefficient Thermal



Friction Factor of Soil

s

Fluid (mud) Drag Coefficient

mud

Test Pressue

PT

137.1 Bar

(Test pressure =95 % SMYS)

Design Pressure

P

63.5 Bar

921 lb/in2

11 lb/gal

1318.09 Kg/m3

30022866 lb/in2

0.0000117 mm/mm/°C 0.5 0.05 lb/in

Assumed 2

344.73785 Pa

CALCULATIONS Pipe Cross Sectional Area

656692.89 mm2

0.657 m2

44881.26 mm2

0.045 m2

Steel Cross Sectional Area

As

Uncorroded weight of Pipe

Ws

Displace Mud Weight

W mud

944.20 kg/m

Effective (submerged) weigth of pipe

W sub

-591.89 kg/m

352.32 kg/m

Wsub = Ws - Wmud Earth Pressure Coefficient

K

0.577

Arching Factor



0.148

Page 1 of 5

3 ft

PROJECT: Prepared by: Checked by: HORIZONTAL DIRECTIONAL DRILLING CALCULATION INSTALLATION STRESSES Pulling Loads Straight Section L1 Frcition Force

|Ff1|

15208.75 kg

FD1

51678.38 kg

W p1

8555.98 kg

T1

58331.14 kg

|Ffarc1|

37189.31 kg

FDarc1

124447.14 kg

W parc1

0.00 kg

|Ff1| = W sub x L1 cos (in) x s Fluid Drag FD1 =  x D x L1 X mud Pipe Weight (longitudinal direction) W p1 = W sub x L1 sin (in) Pulling load at end of L1 T1 = |Ff1| + FD1 - W p1

Curve Section Larc1 Frcition Force

 considered 0deg for conservatism

|Ffarc1| = W sub x Larc1 cos () x s Fluid Drag FDarc1 =  x D x Larc1 X mud Pipe Weight (longitudinal direction)

 considered 0deg for conservatism

W parc1 = W sub x Larc1 sin () Pulling load at end of Larc1

Tarc1

219967.59 kg

|Ff2|

73146.80 kg

FD2

244772.22 kg

W p2

0.00 kg

Tarc1 = T1 + |Ffarc1| + FDarc1 - W parc1

Straight Section L2 Frcition Force

 = 0deg for straight section

|Ff2| = W sub x L2 cos () x s Fluid Drag FD2 =  x D x L2 X mud Pipe Weight (longitudinal direction)

 = 0deg for straight section

W p2 = W sub x L2 sin () Pulling load at end of L1

T2

537886.61 kg

T2 = Tarc1 + |Ff2| + FD2 - W p2

Curve Section Larc2 Frcition Force

|Ffarc2|

37189.31 kg

FDarc2

124447.14 kg

W parc2

118652.20 kg

Tarc2

818175.26 kg

|Ff3|

15208.75 kg

FD3

51678.38 kg

W p1

8555.98 kg

 considered 0deg for conservatism

|Ffarc2| = W sub x Larc2 cos () x s Fluid Drag FDarc2 =  x D x Larc2 X mud Pipe Weight (longitudinal direction) W parc2 = W sub x Larc2 sin () Pulling load at end of Larc2 Tarc2 = T2 + |Ffarc2| + FDarc2 + W parc2

Straight Section L3 Frcition Force |Ff3| = W sub x L3 cos (Fout) x s Fluid Drag FD3 =  x D x L3 X mud Pipe Weight (longitudinal direction) W p3 = Wsub x L3 sin (out) Pulling load at end of L1

T3

893618.37 kg

Page 2 of 5

 considered 90deg for conservatism

PROJECT: Prepared by: Checked by: HORIZONTAL DIRECTIONAL DRILLING CALCULATION T3 = Tarc2 + |Ff3| + FD3 + W p3 Pulling Loads

=

893618.37 kg

Page 3 of 5

PROJECT: Prepared by: Checked by: HORIZONTAL DIRECTIONAL DRILLING CALCULATION Tensile Stress t

Tensile stress

19.91 MPa

t = Pulling Loads / Steel Area Allowable Tensile Stress :

90% of SMYS Condition :

373.50 MPa OK

Bending Stress b

Bending Stress

131.45 MPa

b = E D / 2R Allowable Bending Stress D/t

57.51

for D/t < 24.92 < for D/t < for D/t >

24.921 Fb =

45143.08 lb/in2

311.251 MPa

49.842 Fb =

38485.01 lb/in

2

265.345 MPa

49.842 Fb =

39312.27 lb/in2

271.049 MPa

Allowable Bending Stress (Sb) : Condition :

265.34 MPa OK

Hoop (External Pressure) Stress Pext

External Pressure

60 kPa

(Ranging from 30 kPa to 60 kPa)

0.06 MPa Hoop Stress due to External Pressure

hext

1.73 MPa

Elastic Hoop Buckling Stress Fhe

0194318 psi

6E+008 MPa

Critical Hoop Buckling Stress Fhc

87380194318 psi

Fhc

Fhe <

33104.9

15728462063 psi

33104.92 < Fhe <

96305.2

Fhc

68565.10 psi

96305.23 < Fhe <

373183

Fhc

60190.77 psi

Critical Hoop Buckling Stress :

15728462063 psi

373182.77 < Fhe =

Allowable hoop stress = 67% of Critical Hoop Buckling Stress = Condition :

108443971.09 MPa 72657460.63 MPa

OK

Combined Installation Stress Combined Installation Stress should satisfy the following condition:  t / 0.9S +  b / Sb < 1

Condition :

OK

A2 + B2 + 2|A|B < 1

Condition :

OK

A = [ (t + b - 0.5hext) / 1.25] / S

0.4533

B = 1.5 hext / Fhc

0.0000

Page 4 of 5

PROJECT: Prepared by: Checked by: HORIZONTAL DIRECTIONAL DRILLING CALCULATION OPERATING STRESSES Hoop Stress due to Internal Pressure

h

182.59 MPa

b

131.45 MPa

th

-125.94 MPa

h = P D / 2t Bending Stress b = E D / 2R Thermal Expansion th = E  (T1-T2) External Pressure

Pe

52108.43 Pa

0.0521 MPa

Allowable Operating Stress Total circumferential stress

C

180.87 MPa

L

59.77 MPa

C = h - hext Net Logitudinal Stress L = b + th + C  L ≤ 0.9 S =

373.50 MPa

(1) SE1 = | C - L |

sE1

121.10 MPa

2 2 1/2 (2) SE2 = ( C + L - CL )

sE2

159.61 MPa

sE

159.61 MPa

SE ≤ 0.9 S =

373.50 MPa

CRITERIA :

Hence :

OK

Hence :

OK

Combined stress

Combined stress, SE = Max (SE1, SE2) CRITERIA :

Page 5 of 5

7.56 psi