12.1 Literatur Study on Cost Effective Platform (Jacket Design)-Upload

Literature Study on Cost Effective Platform for Marginal Field November - 2016

“Literature Study on Cost Effective Platform for Marginal Field”

Agenda 1. BACKGROUND 2. OBJECTIVE OF STUDY 3. PLATFORM STRUCTURES FOR MARGINAL FIELD 4. BREAKDOWN OF COST 5. CONCLUSIONS AND RECOMMENDATIONS 6. REFERENCES 7. APPENDIX


1. BACKGROUND •

PT. Pertamina Hulu Energi West Madura Offshore (PHE WMO) nowadays have many marginal field development in 30-70 meter water depth ini Madura Offshore Area.

West Madura Offshore Location


1. BACKGROUND •

•

•

PHE WMO is trying to find concepts, which considerably reduce the costs of these marginal field developments and consequently make these developments economically feasible. Most of these marginal developments are based on the "satellite principle", which means that existing pipeline transportation infrastructure and production facilities in the vicinity of the marginal field are used so that the development costs are significantly reduced. Marginal field infrastructure experiences need to be collected to meet the requirements of this study. This study typically deals with the literature study of cost effective platform.


2. OBJECTIVE OF STUDY •

This objective of this study is to analyze and select the suitable platform (monopod, tripod or other) for PHE WMO Marginal Field in West Madura Offshore that have  30-70 meter water depth  about 350 tons topside weight.

•

This study is expected to be a guideline as reference for development concept.


3. PLATFORM STRUCTURES FOR MARGINAL FIELD •

•

Variety of platform concepts have been designed and installed, including platforms for marginal fields in shallow water. Four main groups are identified and characterized based on the structural configuration : A. Structures that use conductors as principal load carrying members

Group

B r o t c u d n o

C d e rt o p p u S

n o s is a C g n i d n ta s e re F

n o s s i a C d te r o p p u

Topside Weight (tons)

0 3 0

0 0 -1 0

0 5 0

Water depth range (m)

0 -2 0

0 -6 0

Number of wells

1

6 o t 1

l a r tu c ru t S

Environmental application

Foundation

B. Structures that do not use conductors as principal load carrying members

A

Installation Method

n io t ra u g fi n o C

Harsh Medium Mild Conductors as piles Gravity based Suction cans Driven piles

g n i d n a t s e e r F

r to c u d n o C

   

 





d o p o n o M

re tu c ru t S p u k c a J

1 P I S

2 P I S

3 P I S

4 P I S

r e w o T t n a y o u B

0 0 -1 0

0 0 -2 0

0 5 3 >

0 5 3 >

0 0 3 0

0 0 2 0

0 0 4 0

0 0 4 0

0 0 4 0

ry a V

0 -4 0

0 -6 0

0 0 1 0

0 0 1 0

0 0 1 0

0 0 1 0

0 -3 0

0 -5 0

0 -3 0

0 -5 0

ry a V

3 o t 1

6 o t 1

6 o t 1

2 1 to 1

6 1 to 1

6 o t 1

S

        

 



  



C. Self Installed Structure Fabrication

Vertical on barge Horizontal on  barge Built vertical Built horizontal



Material

Access possibilities

those principal

Soil application

 

  

6 o t 1

 

ry a V

 

 



 

Steel By boat By helicopter Calcareous soils Soft clay

   

 











Stiff clay Sand

   

 

 

 

 

 



  

  

 













  











 

 



 















    

  

Concrete





 

 

  

 

  

 



 

Hybrid

D. Other Structures that do not use all



  



6 o t 1



  

Self floating Transport

6 o t 1







6 o t 1





Self installable Crane barge Cantilever jack-up

D

t e k c a J l a n o it n e v n o C

 

C t e k c a J t h ig a tr S

 









 









 

 

 













  

 








3. PLATFORM STRUCTURES FOR MARGINAL FIELD A. Structures that use conductors as principal load carrying members

•


C. Self Installed Structure

D. Other Structures that do not use all those principal

There are two(2) structures in this group: 1. Freestanding conductors 2. Supported conductors One of supported conductor type which is known is Stacked Template Structure (STS) and Tall Template Structure (TTS) platform.

•

These structures are suitable for area which have mild environmental load (wave and current), minimum topside weight and shallow water depth





Typic al Condu cto r Suppo rt ed Pla tf orm







Stacked Template Stru ct ur e (STS)






•

•

TallTemplate Stru ct ur e (TTS) The TTS acts as a drilling template with 30” conductors drilled and grouted into the i.e. three (3) 36” legs and doubling as structural piles. Four internal i20” conductors can be supported within the TTS thus accommodating seven wells in total.

Source: SANTOS Oyong Field Development


3. PLATFORM STRUCTURES FOR MARGINAL FIELD A. Structures that use conductors as principal load carrying members •

•

•

•

•




There are six (6) structures in this group: 1. Caisson 2. Supported caisson 3. 4. Monopod Straight jacket 5. Conventional 3- or 4-leg jacket 6. Jack-up structure Structures number 1 & 2 are suitable for area which have mild environmental load (wave and current), minimum topside weight and shallow water depth. Other structures (number 3 to 6) are applicable for harsher environment, more topside weight and more deep water depth in shallow water. Especially for jack-up structure, since it uses shallow foundation, it needs more study on structural integrity under harsh environment loads. More information about structures that use and do not use conductors as principal load carrying members is shown in Appendix A.








•




There are four (4) structures in this group: 1. Self Installed Platform 1 (SIP 1) 2. Self Installed Platform 2 (SIP 2)

Comparison of Characteristics Among Several Types of Platform with Self Installed Platform for Marginal Field

3. Self Installed Platform 3 (SIP 3) Self 400 PreInstalla tonnes drilling ble topside

4. Self Installed Platform 4 (SIP 4) •

•

These structures are suitable for minimal environmental load since they use shallow foundation and minimal topside weight must be considered. There are four concepts exist for these structures, more study about self installed platform is shown in Appendix B.

Relative Weight in 35 Low Cost meter Removal water depth High No

Jacket Braced Tower Conductor sup

No

Yes

Yes

No

Yes

Yes

Low

No

No

No

No

Low

No

Monotower

No

30 m max Low High Low High

Yes Yes Yes Yes

SIP 1 SIP2 SIP3 SIP4

Yes Yes Yes Yes

Perhap No s No No Yes Perhaps Yes Yes Yes Perhaps

No






Group Study of Marginal Field Satellite Field SELF INSTALLING – SIP I

Advantages • Transport floating on suction piles

Disadvantages • Separately installed topsides

Group Study of Marginal Field Satellite Field SELF INSTALLING – SIP II

Advantages • No lifting required at location • Docking over pre-drilled wells • Re-usable • Maximized onshore commissioning

Disadvantages • Too large to be considered marginal • Larger deck width

Existing StudySubstructures on Marginal Field Platform SELF INSTALLING – SIP II

A 9,000t F3FA SIP2 platform installed.

Group Study of Marginal Field Satellite Field SELF INSTALLING – SIP III •

Advantages

• No heavy lift vessel • Docking over pre-drilled wells • Re-usable • Maximized onshore commissioning •

Disadvantages

• Topside weight limited • Temporary frame required on barge

Group Study of Marginal Field Satellite Field SELF INSTALLING – SIP IV

Advantages • No heavy lift vessel • Docking over pre-drilled wells • Re-usable • Maximized onshore commissioning

Disadvantages • Deck and substructure weight too high for a marginal concept •



•




There is one (1) structure in this group: Buoyant Tower

•

•

•

Until this report arranged, there is only one (1) structure installed in Peru. Detail literature study is shown in Appendix C. It is required further study which considers many technical and cost aspects to determine its suitability and applicability in Indonesia water especially in PHE WMO field.





1st shallow w ater buoyant tow er on of fsh ore P eru



3. PLATFORM STRUCTURES FOR MARGINAL FIELD Suitable Platform for PHE WMO (1/7) •

•

PHE WMO Marginal Field in West Madura Offshore constraint criteria: –

30-70 meter water depth

–

about 350 tons topside weight.

Comments of structural configuration for PHE WMO Field: Group A

B

C

D

Structural Configuration Freestanding Conductor Supported Conductor Freestanding Caisson Braced/ Supported Caisson Braced Monopod/ Monotower

Comments Not Recommended

Reason Small topside weight capability, Many integrity problem during Operational & maintenance

Not Recommended Not Recommended

Small topside weight capability

Less Recommended

Small topside weight capability

Recommended

For limited 1-6 well. Need improvement in brace support for more wells or more topside weight.

Straight Jacket (3 & 4 leg)

Less Recommended

Not effective because has less capability to encounter higher environmental load better than batter leg type

Conventiona l Jacket (3 & 4 leg)

Recommended

Jackup Structure SIP 1

Not Recommended Not Recommended

Spreadbase 3 -leg jacket/tripod is recom mended for 1-6 well. Conventional batter 3-leg jacket/tripod is recommended for 1-15 well. Conventio nal batter 4-leg jacket is recommended for 1-16 well if smaller pile diameter and higher environmental load is considered. Not effective, problem on difficult soil condition Not proven yet, problem on difficult soil condition

SIP 2

Not Recommended

Not much proven yet, problem on difficult soil condition

SIP 3

Not Recommended

Not proven yet, problem on difficult soil condition

SIP 4

Not Recommended

Not proven yet, problem on difficult soil condition

Buoyant Tower

Not Recommended

Not proven yet, need further study


3. PLATFORM STRUCTURES FOR MARGINAL FIELD Suitable Platform for PHE WMO (2/7)












4. BREAKDOWN OF COST 4.1. Platform Cost Breakdown (1/2) •

•

The cost breakdown of a marginal field over the various activities holds the key to cost reduction and better insight into areas of practical improvement . Based on historical project cost and cost estimates for current projects the typical cost breakdown of a field development is as follows: Field development cost breakdown:[Ref 1]

•

 Wells

= 55 %

 Pipeline

=15%

 Platform

= 30%

Cost can be optimized from the beginning if development cost effective strategy is implemented. For example, a platform construction with 20 wells can be compared to two (2) platforms and 10 wells for each platform. The second option may be better from cost aspect.


4. BREAKDOWN OF COST 4.1. Platform Cost Breakdown (2/2) •

The above-table shows that the platform costs are approximately 30 of the total field development costs. Analysis of the cost components for marginal fields shows the following breakdown for the platform cost: Platform cost breakdown: [Ref 1]

•

•

•

 Design & engineering  Procurement

=15 % = 15 %

 Fabrication

= 20%

 Installation

= 50%

It is noted that thecost breakdown may vary considerably depending on specific circumstances, but it is concluded that the installation costs are the key cost driver for a marginal platform. These costs can in many cases amount to about 50% of the total platform costs; especially if the installation is taking place using scarce, purpose-built and high-cost heavy lift installation vessels. The installation cost varies method and location waterdepend depth. on structural size and weight, load out & installation


4. BREAKDOWN OF COST 4.2. Reduction of The Installation Costs •

The assessment of existing platform concepts and their cost structure led to the conclusion that the choice for any concept is closely related to the method of installation, as it constitutes approximately 50% of the total support structure costs.

•

•

Recognizing the impact of the installation activity, it has been concluded to focus on that activity to achieve cost savings. The three following ways have been identified to reduce the installation costs and consequently the total cost of a marginal field development.


4. BREAKDOWN OF COST 4.2. Reduction of The Installation Costs 1st Alternative

•

2nd Alternative

3rd Alternative

4th Alternative

Use established and proven installation equipment, but try to control the activity by applying a better contract strategy between the oil companies and the contractors.


4. BREAKDOWN OF COST 4.2. Reduction of The Installation Costs 1st Alternative •

•

2nd Alternative

3rd Alternative

4th Alternative

Sharing facility with drilling division. Use a jack-up rig already on location for drilling purposes, which apart from its lower dayrate does not hav e additional mob/demo b costs. But there are some note to be considered when choosing this method:  Jack up rig only pile straight leg platform type.  Platform weight limited to jack up rig crane capacity (i.e. <150

tonnes jacket weight)  Topside weight limited to jack up rig crane capacity  Need additional buoyancy tanks to stabilize the platform  Need good designed platform self buoyancy



2nd Alternative

3rd Alternative

4th Alternative

Sample of Installation Sequence using Jackup Rig (1/2)



2nd Alternative

3rd Alternative

4th Alternative

Sample of Installation Sequence using Jackup Rig (2/2)



•

2nd Alternative

3rd Alternative

4th Alternative

Sharing facility with pipeline installation. Use pipeline derrick lay barge to lift and install the platform rather than conventional derrick barge. So its mob-demob can be shared with platform installation. But there are some notes to be considered when choosing this method:  Potential cheaper if pipeline installation really need big barge

capacity.  Platform type not limited, can be straight or batter leg  Platform weight limited to derrick barge crane capacity  Topside weight limited to derrick barge crane capacity  Derrick barge crane must have two slings.



2nd Alternative

3rd Alternative

4th Alternative

Sample of Installation Sequence using Derrick Barge



•

2nd Alternative

3rd Alternative

4th Alternative

Use self-instalIable platforms, thus avoiding the use of expensive installation equipment. But Platform capacity must be considered. Cost reductions by applying a better contract strategy between the oil companies and the contractors may also be realized, but these will not be discussed in this study. This literature study concentrates typically on the existing cost-effective platform, which may be resulted from an assessment of the abovementioned alternatives 2, 3 and 4.


4. BREAKDOWN OF COST 4.3. Platform Breakdown Cost Alternative This sub-section analyzes alternative cases feasible for every platform and installation cases. Percentage and real cost of every component are relative to platform location and world market dynamics.

•

Platform Br eakdown Cost Alternative Case s Guideline A

No

CostComponent

g in d n a t s e e r F

Relative Percentag e of Cost 1

B

r to c u d n o C

g in d n a t s e e r F

r to c u d n o C

d te r o p p u S

d te r o p p u S

n o s is a C

t e k c a J t h g i rta S

d o p o n o M

n o s is a C

l a n o it n e v n o C

C

e r u t c ru t S p u k c a J

t e k c a J

1 IP S

D

2 IP S

3 IP S

4 IP S

1

Design&EngineeringCost

2

ProcurementCost

10-15%

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

3

FabricationCost

15-20%

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

4

Installation Cost( Alternatives) a. Derrick Barge

5

– 15%

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

r e w o T t n a y o u B

Yes

30- 50%

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

Yes

b. Sharing with Pipeline (Installed by Derrick Lay Barge)

May be

May be

May be

May be

May be

May be

May be

May be

No

No

No

No

May be

c. Sharing with Drilling (Installed by Jack-up Rig)

Yes

Yes

Yes

Yes

Yes

Yes

May be

No

No

No

No

No

May be

d.Self Installing

No

No

No

No

No

No

No

No

Yes

Yes

Yes

Yes

No


5. CONCLUSIONS AND RECOMMENDATIONS •

From structural applicability and cost breakdown consideration, conclusions and recommendations below should be considered: 1) There are three main g roups of platform ty pe that can be applied in marginal field, they are: platform that use conductors as principal load carrying members (freestanding conductor, supported conductor), platform that does not use conductors as principal load carrying members (caisson, supported caisson, monopod, straight jacket, conventional 3- or 4- leg jacket, jack up structure), and self installed platform (SIP 1, SIP 2, SIP 3, and SIP 4). 2) To choose the most suitable and lowest cost platform for marginal field, it must consider the rate of field production that the deck weight can be determined, number of wells, water depth, environmental load condition (wave and current), foundation type, methods of installation, transportation, fabrication, material type, and soil type.


5. CONCLUSIONS AND RECOMMENDATIONS 3)

4) 5)

Freestanding conductor and supported conductors can be applied for the field that has water depth up to 20 m and 60 m, respectively. Freestanding and supported caissons are for water depth up to 40 m and 60 m, respectively. Braced monopod/monotower, straight jacket, conventional 3- or 4- leg jacket, and jack up structure can be used can be applied for the field hasup water up toSIP 100 m. SIP SIPfor 3 are for waterthat depth to 30depth m, while 2 and SIP14and 3 are water depth up to 50 m. Platform types that can be used to carry the topside weight until 400 tonnes are straight jacket, conventional 3- or 4- leg jacket, SIP 2, SIP 3, and SIP 4. Monopod, straight jacket, conventional 3- or 4- leg jacket, and jack up structure can be applied in the field that has the harsh environmental load condition, while supported conductor, freestanding caisson, supported caisson, SIP 2, and SIP 4 can be in the medium environmental load condition field. Freestanding conductor, SIP 1, and SIP 3 can only be applied in the mild environmental load condition field


5. CONCLUSIONS AND RECOMMENDATIONS 6)

Cost optimization can be performed considering the reduction of installation cost. All possible cases, methods and strategy to reduce installation cost should be considered. These are specific for every case.

7)

Freestanding conductor and supported conducter are not recommended for PHE WMO because they have small topside weight capability, and many

8) 9)

integrity problem had found during operational & maintenance Freestanding Caisson is not recommended for PHE WMO because small topside weight capability. Braced/ Supported Caisson is less recommended for PHE WMO since the topside weight limitation (350 tonnes) is bigger than its topside weight capability.

10) Braced monopod/monotower is RECOMMENDED for PHE WMO. But for limited 1-6 well. Need improvement in brace support for more wells or more topside weight.


5. CONCLUSIONS AND RECOMMENDATIONS 11) Conventional Jacket (3 & 4 leg) is RECOMMENDED for PHE WMO. Spreadbase 3-leg jacket/tripod is recommended for 1-6 well. Conventional batter 3-leg jacket/tripod is recommended for 1-15 well. Conventional batter 4-leg jacket is recommended for 1-16 well if smaller pile diameter and higher environmental load is considered. 12) Straight Jacket (3 & 4 leg) is less recommended for PHE WMO since straight type structural configuration is not effective because it has less capability to encounter higher environmental load better than batter leg type. But for installation consideration for example using jackup rig installation, it may be considered. 13) Jackup Structure is not recommended since it is not effective for PHE WMO area and there is problem with difficult soil. 14) Self Installed Platform and Buoyant Tower is not recommended yet, since they are not proven yet in Indonesia Offshore.


6. REFERENCES 1.

H.J. Meek, P.G.F. Sliggers , “Alternative Low-Cost Wellhead Platform Concept(s) for Marginal Offshore Field Developments”, Proceedings of the Eleventh (2001)lnternational Offshore and Polar Engineering Conference Stavanger, Norway, June 17--22, 2001

2.

LAPI ITB “Studi Pengembangan Konsep Desain Anjungan Lepas Pantai Tepat Guna”, work donated by BPMIGAS, Bandung, December 2004.

3.

Iv Oil & Gas, “Development of A Marginal Sattelite Field” a presentation slide, accessed from http://www.slideshare.net/Sander_van_oirschot/presentationwebsafe on July 9th, 2013.

4.

http://www.offshore-technology.com/projects/corvina-oil-gas-field-peru/corvina-oil-gas-field-peru1.html , accesed 19 July 2013.

5.

http://www.faqs.org/sec-filings/120517/BPZ-RESOURCES-INC_8-K/a12-12471_1ex99d1.htm#b, accesed 20 July 2013

6.

http://www.worldoil.com/October-2012-Drilling-advances.htmlaccesed 23 July 2013

7.

http://www.offshore-technology.com/projects/ accesed 23 July 2013

8.

http://www.hortonwison.com/technology/buoyant-tower/ accesed 24 July 2013

9.

T-Time Magazine No.1 2013 , page 5.

10. http://www.epmag.com/EP-Magazine/archive/A-marginal-field-approach_2805 accesed 17 May 2013 11. Chakrabarti Subrata, “Handbook of Offshore Engineering by Vol 1”, Offshore Structure Analysis, Inc., Plainfield, Illinois, USA Elsevier, 2005 12. Offshore Magazine, (January 2001). “2001 Worldwide Survey of Minimal Offshore Fixed Platforms & Decks for Marginal Fields”. 13. Martec, “Minimal Structures for Marginal Nova Scotia Developments”, a presentation slide May 12 2009. 14. Nicholson, Graham, et all “Modular Design for Low Cost Minimum Facilities Platforms”, Offshore South East Asia Conference, Singapore, November 2012. 15. Bob Manley, “Minimal structures open global production opportunities” Offshore Magazine January 1999.


7. APPENDIX APPENDIX A - World Experience on Typical Offshore Platform for Marginal Field APPENDIX B - Literatur Study on Buoyant Tower APPENDIX C - Sensitivity Analysis on Marginal Field Fixed Platform APPENDIX D - Amoco Study for Marginal Field Minimal Platform APPENDIX E - Offshore Magazine Survey & Martec Study for Marginal Field Structure APPENDIX F- iV-Group Study of Marginal Field Satellite Field


APPENDIX – A “World Experience on Typical Offshore Platform for Marginal Field”

World Experience on Typical Offshore Platform for Marginal Field •

•

There are more than 100 minimal structure designs and most of these were intended to support deck payloads of 400-1000 tons and transmit the functional and environmental loads to the seafloor through driven or drilled and grouted piles. Some of the other structures carry larger deck payloads and/or rely on gravity base structures, rather than piles, to transmit the loads to the seafloor. Although each minimal structure design is unique, these designs can be grouped into structure types defined as Tripods, Braced Caissons, Braced Monopods and Monotowers.

Novel Fixed Struct ures (from Offsho re Magaz ine, January 200 1)

Type

Tripod

Caisson and Braced Caisson

Monotowe r

Name Unit

Company Name

SeaHorse III

Atlantia

EMOP-3S

Enercon

Skirt pile Tripod

Mustang

Tripod

Pinnacle

Caisson

Atlantia

Caisson

PetroMarine

Sea pony

Atlantia

Braced Caisson

Worley

Varg(NS)

Aker

AMOSS

BPAmoco

Monopo d (NS) {Modified AMOSS}

Brown & Root

SASP

Saipem

[Ref 12]

Production MMscfd BOPD

Steel Weight (tons)

Water Depth m (ft)

60 5000 100 8000 80 2000 60 1000 25

1200

35 3000

300

92 (300) 122 (400) 132 (433) 114 (375) 27.4 (90) 49 (161)

25

520

50 20000 55 57000 180

620 4600

800

5100

2300 2800 1500 300

1380

80000 300

61 (200) 73 (240) 36.5 (120) 41 (135) 33 (108)

1310

54.9 (180)

World Experience on Typical Offshore Platform for Marginal Field 1. Tripod •

Tripods: A typical Tripod is a tubular space frame consisting of three legs and the bracing system that connects the legs. It is secured to the seafloor with three piles.

•

Some of the more distinctive tripods are Atlantia’s SeaHorse 111, Enercon’s EMOP-3S, Mustang’s Skirt Pile Tripod and Pinnacle Engineering’s Tripod .

Typical Tripod Platform

World Experience on Typical Offshore Platform for Marginal Field 2. Caissons and Braced Caisson •

•

•

A Caisson is a relatively large-diameter cylindrical shell that supports a small deck and this type of a structure is applicable to relatively shallow water depth sites. The Caisson structures installed in deeper water are provided with a bracing system to resist lateral loading. A Caisson that may be subjected to hurricane loading is typically limited to water depth sites of about 50 m (165 ft) while the Braced Caisson makes it cost-effective to utilise these Caissons to sites with water depths of 80-100 m (260330 ft).

World Experience on Typical Offshore Platform for Marginal Field 3. Monotower / Monopod •

•

•

A typical monotower is a large-diameter cylindrical shell supporting a deck structure and it transfers the functional and environmental loads to the foundation through the framing system and the piles. Typically, a monotower is supported by four piles at four corners of the framing system. The size of the monotower and the restraining system (i.e. framing system and piles) depend on the deck payload and the environmental condition. Thus, as illustrated in Table A- 1, the structures identified to be in the harsh North Sea environment would require substantial steel to resist wind, wave and current loads.

Typical monotower platform: Monopod in Alaska, USA (Up ),platform Per tamina APN A Platform (Down)

World Experience on Typical Offshore Platform for Marginal Field 4. Conductor Supported Platform •

Conductor Supported Minimum Offshore Structures (known as CoSMOS platforms), utilize the well conductors to support the topsides thus eliminating the need for a separate supporting jacket structure.

•

•

They offer particular benefits in terms of modular design, fast procurement, low fabrication cost as well as ease of installation since they can be installed from a jack-up or crane barge without the need for costly installation vessels. An example of showing the installation of a CoSMOS platform for the Olowi field offshore Gabon

Standalone MFP (Olowi Field Offshore G abon)

World Experience on Typical Offshore Platform for Marginal Field Two Ways of Installation Method

Installa tion wi th a Crane Barge ( Left) or Jackup (Right)

World Experience on Typical Offshore Platform for Marginal Field 5. Self elevating platform Self elevating platform can use existing jack-up structure to be a platform. –

–

–

–

–

Key features of this platform are: Platform self-installs using lift mechanism at offshore site. Foundations typically gravity based Suitable for larger, heavier equipment requirements.

Deep Panuke PFC, (2010)

World Experience on Typical Offshore Platform for Marginal Field 6. Self Installed Platform •

Self installed platform is a platform that do not need derrick barge or drilling rig in its inatallation.

Self Installed Platform (SIP Type II)


APPENDIX – B “Group Study of Marginal Field Satellite Field”

Group Study of Marginal Field Satellite Field CRANE/BARGE INSTALLED - MULTILEGGED JACKET

Advantages • Proven concept • Supports all marginal topsides • Can support work-over units

Disadvantages • Requires heavy lift vessel • Main pile jackets require field welds • High installation costs

Group Study of Marginal Field Satellite Field CRANE/BARGE INSTALLED – MINIMAL BRACED

Advantages • Low weight

Disadvantages • Requires heavy lift vessel • Limited future expansion • Jack-up rig required for work-over

Group Study of Marginal Field Satellite Field RIG/BARGE INSTALLED – CONDUCTOR SUPPORTED

Advantages • Cost effective

Disadvantages • Topsides limited to 200 tonnes • Permitting

Not to be pursued

Group Study of Marginal Field Satellite Field RIG/BARGE INSTALLED – CONDUCTOR SUPPORTED

Advantages • Low weight • Protected conductors and risers Disadvantages • Cannot pre-drill wells • Work-over requires drilling rig

• Limited topside weight • Sensitive to dynamic motions  fatigue  additional bracings

Group Study of Marginal Field Satellite Field PLATFORM CONCEPT COMPARISON

Jacket

Self Installable

400 tonnes topside

Pre-drilling

Relative Weight in 35 meter wat er

Low Cost Removal

No

Yes

Yes

High

No

Braced Tower

No

Yes

Yes

Low

No

Conductor sup

No

No

Yes

Low

No

Monotower 1 SIP SIP 2 SIP 3 SIP 4

No Yes Yes Yes Yes

Perhaps No Yes Yes Yes

No No Perhaps Yes Perhaps

30mmax Low High Low High

No Yes Yes Yes Yes

12.1 Literatur Study on Cost Effective Platform (Jacket Design)-Upload

Recommend Documents