design of offshore platforms

7/23/2019 Design of Offshore Platforms

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Design of Offshore Platforms

Lecture 1

Introduction1



2

Outline

Introducing myself

Course objectives

Course syllabus

Course application

Class policies

Reference books

2



3

Introducing myself

PhD, The Universityof Texas at Austin

Research interests:

OffshoreEngineering

MarineHydrodynamics

SedimentTransport

Renewable Energy

FPSO

3

FPSO

FPSO



4

Offshore Engineering

Simulation of Platforms/Risers/Pipelines

4



5

Renewable energy5

Danish west coast



6

Class time

Class times: Mondays, 6:00-7:30 pm

TA Class times: Tuesdays, 6:00-7:30 pm

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7

Course objective:

Introduces the student to

loading,

behavior,

analysis and

design of offshore platforms

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Description:8

This is intended as an advanced course in the

Marine Structures area.

It is assumed that the students have the basic

knowledge of the structural analysis,

marine hydrodynamics and

steel structures design The course focuses on design of fixed platforms and

it only introduces the floating platforms.



9

Course Evaluation:9

Term Project/Homeworks: 40%

Final Exam: 60%

Pop-up quizzes/ 5 Min. Presentation : Extra scores



10

Class policies10

Original homework/project must be submitted by

each student.

The assignment will be graded for solution

procedure, numerical results, clarity and appearance.

Late assignments will not be accepted.



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Course Outline:11

تی

س ار ص رم و چخر مدم

رد يوس عاوا شآ

و

گژو

درم

رري

... و يز تث يوس رم-وش يوس رم

ز

ثت

سوي

ز تث يوس مر ازا

ز

ثت

سوي

سسمي

رم

دسا دراوم و يز تث يوس بم و ازم



12

Course Outline:12

س

برگذاري

فرع

ث ير:دز و هدرم ير

درم ير:آ نشم يدرم يور وزن مشن آت

ش و يور غرات رارت ش از مرد مشن آت

مط

ري

:م

رارت

غرات

رن

مد

و

زر

موج

د

وضوم رس:

Marine Growth, Vortex Shedding, Wave Slamming

ص نمز يراذگر

ژو

ا:ري

ش

رخورد

زز

ارط ير بر



13

Course Outline:13

س وآنلیز

حارط

و

س يزآ رم و م

ارط لوادم ي م نآ رم

(API-RP2A – Noble Denton-DNV)

رر نمز رد زآ

:Inplace

ص

زمن

آزي

: Loadout, Tow, Lift, Launch, Floatation & Upending

ژو

ري

ت

:آز

Fire, Dynamic Loading, Earthquake, Boat Impact, Explosion

ا

و

اصت

ارط

و

:(Tubular Joints)آز

سخ

آز

:(Wind & Wave Fatigue)مخ

روشي

و

ط

...مش ارط و زآ

((Pile Design



14

Course Outline:14

حس

فرا

ي

سزه

حارط

و

آنلیز

افزاري

نرم

ب

ینشآ

ونش يو س

رف

– درر

– ارط

روشی



15

Main References:15

Useful websites: http://www.fgg.uni-lj.si/~/pmoze/esdep/master/wg15a/toc.htm

www.offshore-mag.com

زن

دكر

مر

ثت

سكوي

اراي

و

ارط

دا

رد يوكس يارا و حرط م دشوخ کمس

http://www.fgg.uni-lj.si/~/pmoze/esdep/master/wg15a/toc.htm

http://www.offshore-mag.com/












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Other References:16

قدص

ر

رد

ی

سزه

و

در

سوال

سدم

ی هزسس رد

لگ مری رد ی هزسشا



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Other Reference:17

S. K. Chakrabarti, 2005. HANDBOOK OF OFFSHORE ENGINEERING, ELSEVIER.

B. C. Gerwick, 2007. Construction of Marine and offshore structures, CRC press.

Ivar Holand, Ove T.Gudmestad and Erik Jersin, 2000. Design of Offshore ConcreteStructures, Spon press.

Patel, Minoo H., 1989. Dynamics of Offshore Structures, Butterwork & Co. Ltd.

S. K. Chakrabarti, 1987. Hydrodynamics of Offshore Structures, Springer. Dawson, Thomas H., 1983. Offshore Structural Engineering, Prentice-Hall Inc.

Hsu, Teng H., 1984. Applied Offshore Structural Engineering, Gulf PublishingCompany.

Robert T. Hudspeth, 2006. WAVES AND WAVE FORCES ON COASTAL ANDOCEAN STRUCTURES, World Scientific Publishing Co.

John B. Herbich, 1999. DEVELOPMENTS IN OFFSHORE ENGINEERING, GulfPublishing Company.

James F. Wilson, 2003. Dynamics of Offshore Structures, John Wiley & Sons, Inc.



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Progress to deep water

offshore drilling and production of petroleum

resources:

Steady progress to deep water1947-1998

Water depth: 6 m to more than 500 m

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Design for waves loads

platforms are designed for wave heights up to the order

of 25 meters

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Cost

Expensive Structures

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Platform Failure

It requires a good estimate of environmental forces

(wave, wind, current, …) to avoid failure.

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1ST Lecture Objective

identify the basic vocabulary

introduce the major concepts for offshore platform

structures

explain where the basic structural requirements fordesign are generated



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Outline

Definition

Application

Importance

basic steps in the development process

major structural concepts

Fixed

Floating

major codes



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Definition

Offshore Platform: a structure in the sea that does

not have direct access to the land



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Application of offshore platforms

Oil and gas industry

Geotechnical surveys

Offshore wind turbines

Military purpose



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Importance for Iran

Ranking of Oil/Gas recoverable reserves

155

1166



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Importance for Iran

Most of Iran’scommon

reservoirs are

offshore

Foroozan

(common with

Saudi)

Arash (commonwith Kuwait)

South Pars

(common with

Qatar)



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Ranking of Oil Companies

1. Saudi Armco

2. NIOC

3. Exxon Mobile



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COST ASPECTS

The economic feasibility of an offshore project depends onmany aspects:

capital expenditure (CAPEX),

operational expenditure (OPEX)

tax royalties

In a typical offshore field development the CAPEX isdivided to:

1/3 on the platform 1/3 on the drilling of wells

1/3 on the pipelines



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OFFSHORE DEVELOPMENT OF AN OIL/GAS FIELD

Factors involved in the evaluation

number of wells required

fixed or floated production facilities

pipeline or tanker off-loading



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main technical activities prior to production:

engineering and design

fabrication and installation

drilling of production wells providing the off loading system

Pipelines

Tankers



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Offshore Platforms

Includes

Superstructure:

supports the equipments

Substructure:withstand weight of

superstructure + Env. Loads



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Superstructure

design depends on

capacity of production

type of reservoir



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Substructure

design depends on

Weight of superstructure

Environment

water depth at location soil, at sea-bottom and in-depth

wind speed, air temperature

waves, tide and storm surge, current

ice

earthquakes



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Hydrocarbon Superstructures functions

Reservoir drilling

Oil/gas production

Oil/gas storage

Personnel accommodation

Flare

Support bridges

A combinations of above functions



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2. Major structural concepts

Fixed

Jacket

Compliant tower

GCS TLP

Floating

FPSO Spar

Semi-submersible

Fixed/Floating: Jack-ups



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Water depth definition

h<1300 ft Shallow water

1300 ft<h<5000 ft Deep water

h>5000 ft Ultra-deep water



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Platforms types versus water depth



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Fixed Platforms



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Jackets

majority of platforms are piled-jacket all built in

steel



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Gravity concrete structure (GCS)

North Sea



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Compliant Towers



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TLP 43

http://www.offshore-technology.com/projects/rampowell/



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Floating Platforms44



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Semi-submersible 45



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Anchorage via 8 cable chain system



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•Anchorage via 8 cable-chain system•Platform weight: 14000 ton



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FPSO

Goodfor PG,WA,

Brazil,Asia

OFFLOADING



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OFFLOADING

FLOATING HOSE REEL 50

FPSO



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Spar51



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World's deepest platform

Perdido Spar in the Gulf of Mexico

water depth of 2,450 m (8,000 feet)

weigh around 55,000 tonnes



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Transportation of Perdido



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Jack-up Platforms



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Construction

These factors combined with the size and weight of

the items, require that a designer must carefully

consider all construction activities between shop

fabrication and offshore installation.



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Codes

API-RP2A: worldwide leading structural code for

jacket platforms

Lloyds rules

DnV rules

9-300اران



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Certification and Warranty Survey

Government authorities require that recognized

bodies appraise the aspects of structural integrity

and issue a certificate

Insurance companies covering transport andinstallation require the structures to be reviewed by

warranty surveyors before acceptance



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Certification and Warranty Survey

major certification bodies are:

Det norske Veritas (DnV)

Lloyds Register of Shipping (LRS)

American Bureau of Shipping (ABS)Bureau Veritas (BV)

Germanischer Lloyd (GL)



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initial phases which include

seismic field surveying

one or more exploration wells are drilled (Jack-up

drilling rigs are used for this purpose for water depthsup to 100 - 120 m; for deeper water floating rigs are

used)

results are studied and the economics and risks of

different development plans are evaluated



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Factors involved in the evaluation may include

number of wells required

fixed or floated production facilities

number of such facilities pipeline or tanker off-loading



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As soon as exploitation is decided and approved,

there are four main technical activities, prior to

production:

engineering and design fabrication and installation of the production facility

drilling of production wells, taking 1 - 3 months/well

providing the off loading system (pipelines, tankers,

etc.)



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Jacket Based Platform for Shallow Water

First the jacket is installed. The wells are then drilled

by a jack-up drilling unit standing close by with a

cantilever rig extending over the jacket

Design and construction of the topside areprogressed parallel to the drilling, allowing

production to start soon after deck installation



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CANTILEVER

UPPER PACK

LOWER PACK



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Jacket and Gravity Based Platform for Deep Water

The wells are drilled

from a drilling rig on

the permanent

platform Drilling starts after

the platform is built

and completely

installed



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Jacket and Gravity Based Platform for Deep Water

Consequently production starts between one and

two years after platform installation

In recent years pre-drilled wells have been used to

allow an earlier start of the production



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1st Lecture Summary

Class Policies/Syllabus/References

Definitions/ structural concepts

Basic steps in development process

A



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Assignment

Read Section 1 to 3 of

wg15a/l0100.htm#SEC_1

design of offshore platforms

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