Overview of Offshore Structural Engineering for Project Management

16 August 2011

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TABLE OF CONTENTS

1. INTRODUCTION

2. PLATFORM TYPES

3. FIELD LAYOUT

4. PLATFORM TERMINOLOGY

5. FIXED OFFSHORE PLATFORM DESIGN

6. INFORMATION FLOW

1. INTRODUCTION

Proposed : To support Oil & Gas facilities, i.e., Production, Export of Liquid and Gas, Drilling and Living Quarter.

1. INTRODUCTION

Petrochemicals- Methanol- Ammonia- Hydrogen

Onshore &offshore

Steam cracker

(Ethylene)

Associated Gas &

Non Associated Gas

Regional consumers

-Power plant-Fuel gas

Liquefaction

GTL

C5-12

C5-20

Gas Processing Plant

Methane (C1)

Ethane (C2)

C3/C4

Gasoline

Condensate

LPG

Reinjection compressors

Onshore Oil & Gas Field Facilities

Offshore Oil & Gas Field Facilities

CO2 WaterSulphur

2. PLATFORM TYPES

Fixed PlatformFloating PlatformSubsea

3. FIELD LAYOUT

Fixed Platform Field Layout (Sample)

3. FIELD LAYOUT

3. FIELD LAYOUT

Floating Platform Field Layout (Sample)

3. FIELD LAYOUT

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4. TERMINOLOGY

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4. TERMINOLOGY

Jacket / Sub-structureLegHorizontal framingConductor framingCanKnee bracesSea deck walkway

ConductorsCurvedStraight

PilesThrough legPile cluster / Skirt PileBatter v/s straightGrouted v/s ungrouted

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4. TERMINOLOGYMiscellaneous and Appurtenances

Risers and clampCaissons / casingsBoatlandingBarge bumper / fenderJ-tubeFlooding / grouting tubeLaunch cradleMudmatAnodes

5. FIXED OFFSHORE PLATFORM DESIGN

Code and StandardWeight ControlStructural Analysis and DesignStructural Software

1Code and StandardStructural Design must comply with the following Code and Standard :

International Code and StandardAmerican Petroleum Institute (API), International Standard Organization (ISO), American Institute of Steel Construction(AISC), American Welding Society (AWS)

Local Government Regulation

Department of Mineral Fuels, (, ) Owner Specification

Chevron (CES), PTTEP (TOTAL and Arthit), etc.

Classification Body Specification, if requiredAmerican Bureau of Shipping (ABS), Det Norske Veritas (DNV), Lloyds Register of Shipping, Bureau Veritas (BV), Germanisher Lloyds

Warranty Surveyor Specification(Insurance Company for Temporary Phase)

1Weight ControlPurpose :

For monitoring the weight and centre of gravity (C.O.G) of all component parts of a platform

Platfrom weight and Center of Gravity (CoG) is Critical for:

Fabrication and LadoutCapacity of support foundation during fabrication Loadout reaction to confirm loadout equipment and skid beams

Offshore InstallationCapacity of sea transportation and offshore lifting barge/vessel

Platform Operating ConditionBenchmark of platform weight and CoG for structural integrity check

Estimation of Weight and CoG is usually confirmed through Weighting before Loadout

2Weight ControlContingency and Tolerances :

Expressed in terms of a percentage of Base Weight are to allow for weight changes due to the uncertainty of the data, lack of design or final selected vendor data.

Sample of Contingency and Tolerances Percentage

3Weight ControlResponsibilities :

Lead Structural EngineerAssign weight control engineer on the projectInterface, co-ordinate and collect weight data from discipline

Weight Control EngineerResponsible for recording and compiling the weight and centre of gravity

information from all disciplines for generating the weight report

Lead Discipline EngineerResponsible for providing all the necessary information including the weight and COG information of items associated with their disciplines

Updating weight and CoG information

1Structural Analysis and DesignDesign Loading :

Dead Loads (Gravity)- Self weight (Computer generated)

- Miscellaneous Dead Weight (Hand-Coded)

- Equipment, Piping, Instrument and Electrical Dead Weight

- Internal Flood water

- Buoyancy

Live Loads (Movable or Changeable)- Content in Vessels, Equipments and Piping- Storage- Personnel- Crane Lifting weight- Helicopter- Tender Assisted Drilling Rig- Well Servicing Load

Open Area Live Load

2Structural Analysis and DesignDesign Loading :

Operating and Storm Condition

Environmental Loads- Water Depth and Tidal Variation

- Wave

-Current, i.e., Wind Generated and Tidal

- Wind

- Additional Wave Load- On appurtenance item, i.e. anode

- Marine Growth

- Wave slamming

- Snow/Ice

- Earthquake

3Structural Analysis and DesignDesign Loading :

Accidental Loads- Boat Impact

- Fire

- Explosion / Blast

- Drop Object

- Accidental Flooding

Pre-Service Loads- Motion Force- Mating Load

4Structural Analysis and DesignStructural Analysis :

In-service Conditions- In-place

- Dynamic

- Fatigue

- Non-linear Pushover

- Seismic

Pre-service Conditions- Loadout- Transportation- Lifting- Launch - Floating- Upending- On-bottom Stability- Pile Stick-up & Drivability

1Structural Analysis and DesignStructural Software : SACS

Global Response determined from Finite Element Analysis- Usually sufficient with 2-noded beam element

Computer program will automatically- Generate Gravity and Environmental Loads- Consider non-linear pile-soil interaction

- Perform topside and jacket memberand joint code check

- Calculate Pile UC and Safety of Factor

2Structural Analysis and DesignStructural Software : USFOS

Non-linear structural analysis, i.e., Pushover, Fire and Blast, Non-linear Seismic Time History

3Structural Analysis and DesignStructural Software : MOSES

- Barge Stability

- Transportation

- Floating, Launch and Upending

4Structural Analysis and DesignStructural Software : NASTRAN

- General Finite Element Analysis (FEA)

Local Analysis of Connection FEA of Pile Cluster

Structural Software : GRLWEAP- Pile Drivability

5Structural Analysis and DesignStructural Software : BOCAD

- 3D Structural model

- 2D drawings

- MTO

- Cutting Plan

6Structural Analysis and DesignStructural Software : PDMS

- 3D Structural model

- Clash Check

- Weight Take off and CoG

6. FLOW OF INFORMATION

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Flow of Information during Execution Stage

DeliverablesRequired Information

ClientCompany SpecificationsCompany Reference/Standard DrawingsSite Environment DataGeotechnical/Soil Data

Internal Information

Piping Plot Plan / Equipment LayoutMechanical Equipment List and weightE&I Equipment List and weightSafety Drop object, Fire and Blast study

Vendor DrawingEquipment Dimension and weight

Drawing

General Note and Standard Drawing Topside DrawingsJacket & Pile DrawingsDemolition DrawingsOffshore Installation Sequence Drawings

3D BOCAD model3D PDMS model

Document and Report

Basis of DesignProject SpecificationWeight Control ReportDesign Calculation Report

Other DocumentsSite Survey ReportMTOBOM

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