6107999 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 1 of 4 No OF SHEETS DOCUMENT No OFFICE CODE PROJECT No AREA DIS TYPE NUMBER 05 5893 03 P 2 003 01 REV 21.05.07 Issued For IDC DATE DESCRIPTION PD BY JC CHK PD ENG BS PM CEIL Client

Cairn Energy India Limited PIPELINE STABILITY CALCULATION JP Kenny CLIENT SUBJECT DOC NO. PRPD BY DATE Cairn Energy India Limited 24" Crud e Oil Pipeline 05 - 2893 - 03 - P - 2 - 003 Paul Docherty 5-May-07 CHKD BY DATE Jateen Chohan 21-May-07 REV NO. APP'D BY DATE 0 P Docherty 21-May-07 . JOB NO. 5 2893.03 . 1.0 INTRODUCTION The aim of this calculation is to determine the stability of th e pipeline through water course crossings. 2.0 METHOD The method used to determine the stability of the pipeline through wa ter 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 pi peline 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 co nsiders a pipeline free floating in water. In reality the pipeline lays in a tre nch 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 p ipeline. 3.0 REFERENCE DATA The reference data for this calculation has come fro m: Reference 1: ASME B 31.4 Design and OISD - STD - 141 2001 X65 Reference 2: Cr ude Pipeline Design Refer to Wall thickness Report 052893 - 03 - P - 3 - 020 and range of Calculations from 002 to 010 API 5L 4.0 CALCULATIONS 4.1 Pipe Details Nom. Pipe Outside Diameter Specified Wall Thic kness Concrete Coating Thickness 4.2 Coating and Insulation Details Thickness of the outer coating Density of the outer coating Thickness of the Insulation Dens ity of the insulation 4.3 Density and Stability Factor Density External Fluid (W ater) Density Pipe Contents (Empty) Density Pipe Steel Density Concrete Density Soil Density of Liquified Soil Stability Requirement Depth of Cover tp Dp ti Di = = = = 0.008 9771 0.100 589 m N/m m 3 OD t tc = = = 0.610 0.018 0.102 m m m = = = 24 17.5 102 in mm mm = = = = 8.0 996 100.0 60 mm kg/m mm kg/m 3 N/m 3 3 De Di Ds Dc Dg DL Sm H

= = = = = = = = 9810 0 76420 29921 14862 12753 1.1 1.0 N/m 3 3 = = = = = = 1000 0 7790 3050 1515 1300 kg/m 3 3 N/m N/m3 3 N/m N/m 3 3 kg/m kg/m3 3 kg/m kg/m kg/m 3 3 N/m m 03-P-2-003 Rev 01 - 24 inch Stability Empty with insulation.xls 21/05/2007 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 As = pi()*(OD^2-(OD-2 *t)^2) 4 = Weight of steel Ws = = Cross-sectional area - internal Ai = = Weight of pipe contents Wi = = 4.5 Insulation and Protective Coating CSA Insulation Ain = = Weight of Insulation CSA Polyurathane Coating Win Ap = = = = Weight of Coat ing Wp = = pi()*(((2*ti)+OD)^2-(OD)^2) 4 0.223 Ain*Di 131 N/m pi()*(((2*(tp+ti)) +OD)^2-((2*ti)+OD)^2) 4 0.021 Ap*Dp 201 N/m m 2 0.033 As*Ds 2488 m 2 N/m pi()*(OD-2*t)^2 4 0.259 Ai*Di 0 N/m m 2 m 2 4.6 Concrete Coating ( Note: no consideration has been made for reinforcement) O D + 2*(tp+ti+tc) ODT = Total Pipeline Outside Diam. = Cross-sectional area - coa ting Ac = = Weight of concrete coating Wc = = Total Weight of Pipeline Wt 1.0296 m pi()*(ODT^2 -(2*tp+2*ti+OD)^2) 4 0.297 Ac*Dc 8894 N/m m 2 = Wp+Win+Ws+Wi+Wc = 11713 N/m 4.7 Pipeline Buoyancy in Water CSA Pipe+ Ins + coatings At = = Weight of displac ed fluid We = = Required Buoyancy Br = = pi()*ODT^2 4 0.833 At*De 8168 Sm*We 898 4 N/m N/m m 2 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 Bp = = Cross-sectional area of trench Ad = = Submerged weight of soil Wg Wt-Br 2729 N/m (OD+2*ti+2tp)*H 0.826 m2 = Ad*(Dg-De) = 4171 N/m Pipeline Buoyancy, buried Bs = (Wg+Wt)-Br = 6900 N/m 4.8 Pipeline Buoyancy in Liquified Soils Weight of displaced fluid Wm = = Requir ed Buoyancy Bm = = Pipeline Buoyancy, liquified soil BL = = At*DL 10618 Sm*Wm 11 680 Wt-Bm 34 N/m N/m N/m 5.0 Summary of Results The results of the stability calculations are detailed in the following table: Variable Pipeline Buoyancy, open (N/m) Pipeline Buoyancy, buried (N/m) Pipeline Buoyancy, liq soil (N/m) Value 2728.9 6899.9 33.6 Required 0.0 0.0 0.0 OK OK 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...........................