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Cairn Energy India PTY Ltd

BSPL Project - Barmer to Salaya Pipeline

CALCULATION

StabilityCalculation 52893.03

24" Oil Pipeline (Full) 03-P-2-004

1 of 4

DOCUMENT No OFFICE CODE PROJECT No AREA DIS TYPE NUMBER

05 5893 03 P 2 004

01 21.05.07 Issued For IDC PD J C PD BS CEIL

REV DATE DESCRIPTION BY CHK ENG PM Client

PROJ ECT NO.

REF

No OF SHEETS

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JP Kenny

CLIENT .

SUBJECT

DOC NO. .

PRPD BY Paul Docherty

DATE 5-May-07

1.0 INTRODUCTION

 2.0 METHOD

3.0 REFERENCE DATA

 The reference data for this calculation has come from:

Reference 1:

Reference 2:

4.0 CALCULATIONS

4.1 Pipe DetailsNom. Pipe Outside Diameter OD = 0.610 m = 24 in

Specified Wall Thickness t = 0.018 m = 17.5 mm

Concrete Coating Thickness tc = 0.100 m = 100 mm

4.2 Coating and Insulation Details

 Thickness of the outer coating tp = 0.008 m = 8.0 mm

Density of the outer coating Dp = 9771 N/m3 = 996 kg/m

3

 Thickness of the Insulation ti = 0.100 m = 100.0 mm

Density of the insulation Di = 589 N/m3 = 60 kg/m

3

4.3 Density and Stability Factor 

Density External Fluid (Water) De = 9810 N/m3 = 1000 kg/m3

Density Pipe Contents Di = 9618 N/m3 = 980.4 kg/m

3

Density Pipe Steel Ds = 76420 N/m3 = 7790 kg/m

3

Density Concrete Dc = 29921 N/m3 = 3050 kg/m

3

Density Soil Dg = 14862 N/m3 = 1515 kg/m

3

Density of Liquified Soil DL = 12753 N/m3 = 1300 kg/m

3

Stability Requirement Sm = 1.25

Depth of Cover H = 1.0 m

CHKD BY

0

Cairn Energy India Limited J OB NO. 52893.03

24" Crude Oil Pipeline

05 - 2893 - 03 - P - 2 - 004 REV NO.

Cairn Energy India Limi ted

PIPELINE STABILITY CALCULATION

Crude Pipeline Design Refer to Wall thickness Report 052893 - 03 - P - 3 - 020

and range of Calculations from 002 to 010

 J ateen Chohan

 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.

ASME B 31.4 Design and OISD - STD - 141 2001

API 5L X65

 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.

Paul Docherty

21-May-07

APP'D BY

21-May-07

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

DATE DATE

03-P-2-004 Rev 01 - 24 inch Stability Full Crude with Insulation.xls

21/05/2007 Page 2 of 4

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Date...........................

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Cairn Energy India Limi ted

PIPELINE STABILITY CALCULATION

4.4 Weight of Pipeline

Cross-sectional area Steel As =

= 0.033 m2

Weight of steel Ws = As*Ds

= 2488 N/m

Cross-sectional area - internal Ai =

= 0.259 m2

Weight of pipe contents Wi = Ai*Di

= 2494 N/m

4.5 Insulation and Protective Coating

CSA Insulation Ain =

= 0.223 m2

Weight of Insulation Win = Ain*Di

= 131 N/m

CSA Polyurathane Coating Ap =

= 0.021 m2

Weight of Coating Wp = Ap*Dp

= 201 N/m

4.6 Concrete Coating ( Note: no consideration has been made for reinforcement)

 Total Pipeline Outside Diam. OD T =

= 1.0256 m

Cross-sectional area - coating Ac =

= 0.291 m2

Weight of concrete coating Wc = Ac*Dc

= 8700 N/m

 Total Weight of Pipeline Wt = Wp+Win+Ws+Wi+Wc= 14014 N/m

4.7 Pipeline Buoyancy in Water 

CSA Pipe+Ins +coatings At =

= 0.826 m2

Weight of displaced fluid We = At*De

= 8104 N/m

Required Buoyancy Br = Sm*We

= 10130 N/m

4

pi()*OD T 2̂

4

pi()*(((2*ti)+OD)̂ 2-(OD)̂ 2)

4

pi()*(OD T 2̂ -(2*tp+2*ti+OD)̂ 2)

OD +2*(tp+ti+tc)

4

pi()*(OD 2̂-(OD-2*t)̂ 2)

4

4

pi()*(((2*(tp+ti))+OD) 2̂-((2*ti)+OD) 2̂)

pi()*(OD-2*t)̂ 2

03-P-2-004 Rev 01 - 24 inch Stability Full Crude with Insulation.xls

21/05/2007 Page 3 of 4

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Date...........................

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Cairn Energy India Limi ted

PIPELINE STABILITY CALCULATION

Pipeline Buoyancy, open trench Bp = Wt-Br

= 3884 N/m

Cross-sectional area of trench Ad =

= 0.826 m2

Submerged weight of soil Wg = Ad*(Dg-De)

= 4171 N/m

Pipeline Buoyancy, buried Bs =

= 8055 N/m

4.8 Pipeline Buoyancy in Liquified Soils

Weight of displaced fluid Wm = At*DL

= 10536 N/m

Required Buoyancy Bm = Sm*Wm

= 13169 N/m

Pipeline Buoyancy, liquified soil BL = Wt-Bm

= 845 N/m

5.0 Summary of Results

Required

0.0

0.0

0.0

 The buried pipeline will be stable through flooded water courses.

OK 

Pipeline Buoyancy, liq soil (N/m) 844.6 OK 

3883.7

 The pipeline will be stable through flooded water courses where soil liquification has occurred.

 The pipeline in an open trench will be stable through flooded water courses.

Variable

Pipeline Buoyancy, open (N/m)

Pipeline Buoyancy, buried (N/m) OK 8054.8

Value

 The results of the stability calculations are detailed in the following table:

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

(Wg+Wt)-Br

03-P-2-004 Rev 01 - 24 inch Stability Full Crude with Insulation.xls

21/05/2007 Page 4 of 4

Self Check...........................

Date...........................