Pipeline Stability Calculation of 24 Oil Empty

Cairn Energy India PTY Ltd BSPL Project - Barmer to Salaya Pipeline CALCULATION

PROJECT NO.

Stability Calculation 24" Oil Pipeline (Empty)

52893.03 REF

03-P-2-003

No OF SHEETS

1 of 4 DOCUMENT No

01 REV

OFFICE CODE

PROJECT No

AREA

DIS

TYPE

NUMBER

05

5893

03

P

2

003

PD

JC

PD

BS

CEIL

BY

CHK

ENG

PM

Client

21.05.07 Issued For IDC DATE

DESCRIPTION

Cairn Energy India Limited PIPELINE STABILITY CALCULATION JP Kenny CLIENT

Cairn Energy India Limited

SUBJECT

24" Crude Oil Pipeline

DOC NO.

05 - 2893 - 03 - P - 2 - 003

PRPD BY

Paul Docherty

DATE

5-May-07

CHKD BY DATE

Jateen Chohan 21-May-07

JOB NO.

52893.03

.

REV NO.

0

.

APP'D BY

P Docherty

DATE

21-May-07

1.0 INTRODUCTION The aim of this calculation is to determine the stability of the pipeline through water course crossings.

2.0 METHOD The method used to determine the stability of the pipeline through water courses is to calculate the total weight of the pipeline and compare it with the weight of the external fluid (water) it would displace. In order for the pipeline to be considered stable, the pipeline weight must be 10% greater than the weight of the water displaced. The above method is overly conservative as it considers a pipeline free floating in water. In reality the pipeline lays in a trench covered by soil which will provide a hold down force to prevent floatation. This force is calculated by determining the submerged weight of soil above the pipeline. 3.0 REFERENCE DATA The reference data for this calculation has come from: Reference 1: ASME B 31.4 Design and OISD - STD - 141 2001 X65

API 5L

Reference 2: Crude Pipeline Design Refer to Wall thickness Report 052893 - 03 - P - 3 - 020 and range of Calculations from 002 to 010

4.0 CALCULATIONS 4.1 Pipe Details Nom. Pipe Outside Diameter Specified Wall Thickness Concrete Coating Thickness

OD

=

0.610

m

=

24

t tc

=

0.018

m

=

17.5

in mm

=

0.102

m

=

102

mm

tp

=

0.008

m

=

8.0

mm

=

996

3

4.2 Coating and Insulation Details Thickness of the outer coating Density of the outer coating

Dp

=

9771

Thickness of the Insulation

ti

=

0.100

Density of the insulation

3

=

100.0

kg/m mm

3

=

60

kg/m

3

3

=

1000

kg/m

3

N/m m

Di

=

589

N/m

De

=

9810

N/m

Density Pipe Contents (Empty) Density Pipe Steel Density Concrete

Di Ds Dc

= = =

0 76420 29921

N/m N/m3 3 N/m

3

= = =

0 7790 3050

kg/m kg/m3 3 kg/m

Density Soil

=

14862

N/m

3

=

1515

kg/m

3

Density of Liquified Soil

Dg DL

=

12753

3

=

1300

kg/m

3

Stability Requirement

Sm

=

1.1

H

=

1.0

4.3 Density and Stability Factor Density External Fluid (Water)

Depth of Cover

N/m m

03-P-2-003 Rev 01 - 24 inch Stability Empty with insulation.xls 21/05/2007

3

Page 2 of 4

Self Check........................... Date...........................

Cairn Energy India Limited PIPELINE STABILITY CALCULATION JP Kenny 4.4 Weight of Pipeline Cross-sectional area Steel

Weight of steel

Cross-sectional area - internal

As

Ws

Ai

= pi()*(OD^2-(OD-2*t)^2) 4 2

=

0.033

=

As*Ds

=

2488

=

pi()*(OD-2*t)^2

=

0.259

=

Ai*Di

=

0

m

N/m

4

Weight of pipe contents

Wi

2

m

N/m

4.5 Insulation and Protective Coating CSA Insulation

Ain

=

pi()*(((2*ti)+OD)^2-(OD)^2) 4

=

0.223 Ain*Di

Weight of Insulation

Win

=

CSA Polyurathane Coating

Ap

=

=

2

m

131 N/m pi()*(((2*(tp+ti))+OD)^2-((2*ti)+OD)^2) 4

Weight of Coating

Wp

=

0.021

=

Ap*Dp

=

201

2

m

N/m

4.6 Concrete Coating ( Note: no consideration has been made for reinforcement) OD + 2*(tp+ti+tc) ODT = Total Pipeline Outside Diam.

Cross-sectional area - coating

Ac

=

1.0296

m

=

pi()*(ODT^2 -(2*tp+2*ti+OD)^2) 4

Weight of concrete coating

Total Weight of Pipeline

Wc

Wt

=

0.297

=

Ac*Dc

=

8894

2

m

N/m

= Wp+Win+Ws+Wi+Wc =

11713

N/m

4.7 Pipeline Buoyancy in Water CSA Pipe+ Ins + coatings

At

=

pi()*ODT^2 4

Weight of displaced fluid

Required Buoyancy

We

Br

=

0.833

=

At*De

=

8168

=

Sm*We

=

8984

2

m

N/m

N/m

03-P-2-003 Rev 01 - 24 inch Stability Empty with insulation.xls 21/05/2007

Page 3 of 4

Self Check........................... Date...........................

Cairn Energy India Limited PIPELINE STABILITY CALCULATION JP Kenny Pipeline Buoyancy, open trench

Cross-sectional area of trench

Bp

Ad

=

Wt-Br

=

2729

= =

Submerged weight of soil

Wg

Bs

(OD+2*ti+2tp)*H 0.826

m2

= Ad*(Dg-De) =

Pipeline Buoyancy, buried

N/m

4171

N/m

= (Wg+Wt)-Br =

6900

=

At*DL

=

10618

=

Sm*Wm

=

11680

=

Wt-Bm

=

34

N/m

4.8 Pipeline Buoyancy in Liquified Soils Weight of displaced fluid

Required Buoyancy

Pipeline Buoyancy, liquified soil

Wm

Bm

BL

N/m

N/m

N/m

5.0 Summary of Results The results of the stability calculations are detailed in the following table: Variable

Value

Required

Pipeline Buoyancy, open (N/m)

2728.9

0.0

OK

Pipeline Buoyancy, buried (N/m)

6899.9

0.0

OK

Pipeline Buoyancy, liq soil (N/m)

33.6

0.0

OK

The pipeline in an open trench will be stable through flooded water courses. The buried pipeline will be stable through flooded water courses. The pipeline will be stable through flooded water courses where soil liquification has occurred.

03-P-2-003 Rev 01 - 24 inch Stability Empty with insulation.xls 21/05/2007

Page 4 of 4

Self Check........................... Date...........................