Husain Al Muslim Saudi Aramco

HUSAIN M. AL-MUSLIM NADHIR I. AL-NASRI

Outline Introduction  Sabkha area  Road crossing  Bend design  Anchor blocks  Conclusion 

JOR DAN

Saudi Aramco Pipeline Network TURA IF

SAFANIY AH TANAJIB

CRUDE NETWORK GAS Network Product Network

TUFA IH

ABU-ALI

N

ABUHADRIYAH KHURSANI YAH BERRI

IA AB F AR UL G

QAISUM AH

JUBAIL JUBAIL CUSTOMERS Ras Tanoura

JJ

QATIF

BAHRAIN

DHAHRA N RIYADH

ABQAIQ Southern Areas

QATAR

Type of Pipeline Installation Above ground unrestrained pipeline  Above ground fully restrained pipeline  Under ground restrained pipeline 

Sabkha area Sabkha means area of high-level water table  The water is very salty and highly corrosive  The pipe must not come in contact with water  Special pad design and sequence of construction 

Sabkha pad design

Sabkha sequence of construction Prepare the construction pad  Excavate the trench  Lower the pipe and backfill  Construct the pipe berm 

Sabkha area

Construction of ROW and pad

RO

ad P W Sa

ar a h bk

ea ad p e n i l e Pip

p W O R

ad

Preparing the trench

Lowering the pipe and backfilling

Constructing the berm

Stabilizing the berm

Road crossing

Loads on Pipelines Live Load

Earth Load

Internal Load Total Load on Pipeline = Live load + Earth load + Internal Loads

Minimum Depth of Cover Road (1.2 m)

Minimum depth below ditch (0.9 m)

Railroad (1.7 m ) Drainage ditch

Carrier pipe Figure 1: Road Crossing

Minimum depth below surface

Stresses vs. depth of cover 15000

D/t = 50 D/t = 60 D/t = 70 D/t = 80 D/t = 90 D/t = 100 D/t = 110.1 D/t = 120 D/t = 129.9 D/t = 139.9 D/t = 150

14000

Absolute maximum stress (psi)

13000 12000 11000 10000 9000 8000 7000 6000 5000 1

2

3

4

5

6

7

8

9

10

11

12

13

Depth of cover (ft) Absolute maximum stress variation for 60 inch pipe diameter and high density sabkha as native soil

Analysis of Pipeline Under Road & Railroads Methodologies  

Crossi (two versions)  Based on the API RP1102, 1968 edition Cornell/GRI developed PC-PISCESL software  Included in the 1993 edition of API RP1102, Steel Pipelines Crossing Railroads and Highways”  Limitations ○ ○ ○

2 ≤ D ≤ 42 12.5 ≤ D/t ≤ 100 3 ft ≤ Backfill Height ≤ 10 ft

 Pipeline toolbox 

Aramco Study (Analysis and Design for Buried Pipeline. ADBP)  Limitations

50 ≤ D/t ≤ 150 Extended Study 12 ≤ D/t ≤ 150

ADBP 2.0

Minimizing The Pipeline Stresses Under Crossings Installing concrete slab.  Increasing the depth of cover.  Increasing the pipeline wall thickness.  Reinforcing the pipeline with sleeve. 

Pipeline bends Elastic bend  Cold bend  Hot bend 

Bend design The standard design is 210 m radius bend  Smaller radii required calculation and/or thrust anchors  Design was optimized by numerical analysis 

Bend analysis model Pipe Bend A A

Hc

Rb θ

t D Section - AA

Rb

D = Diameter of the pipe t = Thickness of the pipe Hc = Depth of cover Rb = Radius of the bend θ = Angle of the bend

Thrust anchor Full thrust without considering soil friction  Large size anchor blocks  Block size was reduced significantly 

Thrust anchors construction

Thrust anchor new software  Analysis

and Design of Thrust Anchor Blocks (ADTAB)  Size Optimization of Thrust Anchor Blocks (SOPTAB)

Conclusion 

Saudi Aramco standards are dynamic to capture  Lessons learned from projects  Industry best practices  Company funded research projects

Typical Pipeline Construction Activities             

Route Surveying Mobilizing equipment and personnel Transporting and storing pipe and materials Topsoil stripping (as required) Grading Stringing (transport and laying of pipe on the ROW) Welding, ultrasonic, and NDE of welds Installing coating at the pipe joints Trenching Lowering pipe into the trench Installing crossings Backfilling Restoring the ROW

Clearing and Grading

ROW

Grading

Acquisition

Cut and fills

Trenching

Survey

Drilling

Stringing

Stringing

Backfill

Welding / Coating

Welding

Trenching Blasting

Lowering-in

Coating

NDT

Berming /stabilizing

Berm Backfill

Rock

Rock-Free

Stabilizing

Lowering-in

Tie-ins

Padding

Road crossing concrete slab

Casing Requirements 

Casing is required only for railroads.  Casing minimum wall thickness per table -3  Casing diameter ≥ 2 size larger than carrier pipe  Insulators/spacers shall be installed  Casing ends shall be sealed  Vents/drains are not mandatory

Road crossing analysis model 4 m

18 m

D

1.2 min 2.0 max

H 6T

13 T

t

10 T

i

10 T

Scope of SAES-L-460 This standard defines the minimum design and installation requirements governing pipeline crossings under roads, parking lots, railroads, and airport runways.  This standard applies to pipelines in all services.  This standard supplements the latest edition of API RP 1102 “Steel Pipelines Crossing Railroads and Highways.”  Additional requirements imposed by the Saudi Arabian Government shall apply to crossings of Government roads and railroads. 