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ONGC SAGAR SAMRAT CONVERSION PROJECT
SAGAR SAMRAT CONVERSION PROJECT BASIS OF DESIGN Doc. No. 030001910170-GB-001 Revision C
NOTE : This document replaces & supersedes earlier Basis of Design Doc. No. 030001910170-GB-001 Rev. B Of Volume IV Part IX – Section 4.
Mustang Engineering Pty Ltd Level 15, 535 Bourke Street Melbourne Victoria 3000 Ph: 61 3 9211 6480 www.mustangeng.com
Sagar Samrat Conversion Project
Basis of Design
DOCUMENT CONTROL Filename
030001910170-GB-001-C Basis of Design
Total Pages
31
REVISION CONTROL Rev
Date Issued
Description
Author
Check
Eng
PMgr
A
21/01/11
Issued for IDC
MH
SM
SM
GB
B
29/04/11
Issued for Tender
MH
SM
SM
GB
C
Corrected
DOCUMENT SIGNOFF ORIGINATOR
CHECKER
ENGINEER
PROJECT MANAGER
May Hong
Stuart Mackay
Stuart Mackay
Gary Beale
CLIENT
DATE SIGNED
030001910170-GB-001
Page ii of iv
Rev. C
Sagar Samrat Conversion Project
Basis of Design
TABLE OF CONTENTS 1.0
INTRODUCTION ............................................................................................. 1 1.1
GENERAL........................................................................................................1
2.0
ACTS, CODES, STANDARDS AND REFERENCES ...................................... 3
3.0
UNITS .............................................................................................................. 4
4.0
GENERAL DATA ............................................................................................ 5 4.1
CLASSIFICATION SOCIETY RULES ..............................................................5
4.2
TEMPERATURE AND HUMIDITY ...................................................................5
4.3
DELETED ..........................................................................................................
4.4
DELETED ..........................................................................................................
4.5
MOPU LOCATION AND ORIENTATION .........................................................5
4.6
WATER DEPTH AND CHART DATUM LEVEL ................................................6
4.7
MOPU HULL ELEVATION ...............................................................................6
4.8
SOIL BORINGS AND LEG PENETRATION .....................................................6
4.9
WHP CONFIGURATION ..................................................................................6
4.10 MOPU – WHP INTERFACE .............................................................................6 4.11 MOPU TO WHP DOCKING .............................................................................6 4.12 JACKING SYSTEM AND LEGS .......................................................................7 4.13 LIFE SAVING FACILITIES ...............................................................................7 4.14 FIRE AND BLAST PROTECTION ....................................................................7
5.0
6.0
PROCESS FACILITIES DESIGN BASIS ........................................................ 8 5.1
DESIGN LIFE ..................................................................................................8
5.2
WELL FLUID ARRIVAL CONDITIONS ............................................................8
5.3
WELL FLUID COMPOSITIONS .......................................................................8
5.4
EQUIPMENT AVAILABILITY .........................................................................12
5.5
PRODUCTION PROFILE...............................................................................12
5.6
PROCESS DESIGN SPECIFICATION ...........................................................12
5.7
PROCESS DESCRIPTION ............................................................................13
5.8
SUPPORTING STEELWORK ........................................................................17
5.9
PIPING DESIGN ............................................................................................17
MOPU DESIGN BASIS.................................................................................. 19 6.1
TOPSIDES CONFIGURATION ......................................................................19
6.2
HELICOPTER REFUELLING .........................................................................19
6.3
ELECTRICAL DESIGN ..................................................................................19
6.4
INSTRUMENTATION DESIGN ......................................................................22
030001910170-GB-001
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Basis of Design 6.5
STRUCTURAL DESIGN ................................................................................24
7.0
ENVIRONMENTAL DATA TABLES.............................................................. 26
8.0
ARCHITECTURAL DESIGN.......................................................................... 30
9.0
WEIGHT CONTROL ...................................................................................... 30
10.0 REFERENCES .............................................................................................. 31
030001910170-GB-001
Page iv of iv
Rev. C
Sagar Samrat Conversion Project
Basis of Design
1.0
INTRODUCTION
1.1
General
Oil and Natural Gas Corporation limited (ONGC) intends to develop the WO-16 cluster field located in the Mumbai High Field, 140-145 km West of Mumbai. As part of the WO-16 development, ONGC intends to convert the Jackup Drilling Rig Sagar Samrat to a Mobile Offshore Production Unit (MOPU). The converted MOPU will be equipped with facilities consisting of oil, gas and water separation, gas dehydration and compression, chemical injection, flare system, utilities and accommodation. The MOPU will be located adjacent the WO-16 Well Head Platform (WHP) in 76m water depth, where it will receive and process well fluids from WO-16 for an initial period of 6 years, beginning in 2013. Following processing of well fluids at the MOPU, the associated free gas will be compressed for export via the WO-16 WHP. Produced oil will also be exported from the MOPU via the WO-16 WHP. 1.1.1
Abbreviations
ABS
American Bureau of Shipping
API
American Petroleum Institute
BPD
Barrels per day
CCR
Central Control Room
CCP
Central Control Panel
CCTV
Closed Circuit Television
CI
Corrosion Inhibitor
CMD
Cubic metres per day
CRA
Corrosion Resistant Alloy
DCS
Distributed Control System
DGF
Dissolved Gas Flotation
ESD
Emergency Shutdown
EPAX
Electronic Private Automatic Exchange
EWS
Engineering Work Station
F&G
Fire and Gas
GTG
Gas Turbine Generators
HMI
Human Machine Interface
HV
High Voltage
HVAC
Heating, Ventilating and Air Conditioning
030001910170-GB-001
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Rev. C
Sagar Samrat Conversion Project
Basis of Design ICS
Integrated Control System
LAT
Lowest Astronomical Tide
LV
Low Voltage
MDMT
Minimum Metal Design Temperature
MMSCM
Million Standard Cubic Meter
MMSCMD
Million Standard Cubic Meter per Day
MODU
Mobile Offshore Drilling Unit
MOPU
Mobile Offshore Production Unit
MSL
Mean Sea Level
NEC
National Electrical Code
NPS
Nominal Pipe size
OIW
Oil in Water
OLE
Object Linking and Embedding
OPC
OLE for Process Control
PCS
Process Control System
PLC
Programmable Logic Control
PPD
Pour Point Depressant
PPMW
Parts Per Million by Weight
RAM
Reliability and Maintainability
RVP
Reid Vapour Pressure
SCADA
Supervisory Control and Data Acquisition
SIL
Safety Integrity Level
SLD
Single Line Diagram
TEG
Tri Ethylene Glycol
UPS
Uninterruptible Power Supply
WHP
Wellhead Platform
1.1.2
Definitions
COMPANY = ONGC CONTRACTOR = EPC Contractor selected for Phase 3 PROJECT = Sagar Samrat Conversion Project
030001910170-GB-001
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Rev. C
Sagar Samrat Conversion Project
Basis of Design
2.0
ACTS, CODES, STANDARDS AND REFERENCES
Refer to Section 4 of the Bid Package Volume II Part V (Technical Part), Document No. 030001910170-GT-001.
030001910170-GB-001
Page 3 of 31
Rev. C
Sagar Samrat Conversion Project
Basis of Design
3.0
UNITS
SI units should be used for all documents, or per the following examples: Temperature
ºC (Degrees Celsius)
Pressure
kPag (kilopascals gauge), kPaa (kilopascals absolute) or barg (bar gauge)
3
kSm /hr
Thousand standard cubic metres per hour
Mass flow
kg/hr (kilograms per hour)
Gas volume flow
m3/hr (cubic metres per hour), MMSCMD (Million Standard cubic metres per day)
Liquid volume flow
m /hr (cubic metres per hour) BPD (barrels per day)
Heat flow
kW (kilowatts), MW (Megawatts)
Dimensions
m (length), mm (diameter for pipe and general drawings)
Power
kW (kilowatts), MW (Megawatts), hp (horsepower)
N (e.g. Ncmd)
Normal condition
0 C and 101.325 kPaa
S (e.g. Scmd)
Standard condition
15.56oC and 101.325 kPaa
MM
Million
Concentration
ppm (parts per million) mg/Sm³ (milligram per standard cubic metres)
Radiation / Heat
kW/m² (kilowatts per square metres) BTU/hr/ft² (British Thermal Unit per hour per square feet)
030001910170-GB-001
3
Page 4 of 31
o
Rev. C
Sagar Samrat Conversion Project
Basis of Design
4.0
GENERAL DATA
4.1
Classification Society Rules
The basis of assessment of classification issues arising from MODU to MOPU conversion requires that the vessel and its facilities shall continue to be classified by the American Bureau of Shipping (ABS) and subject to ABS Classification Rules. During the Basic Engineering Mid Term Workshop meeting in Mumbai during May 2007, senior ABS representatives advised that ABS can classify the new topsides process facilities under ABS Rules for Offshore Production Facilities, whilst the hull and substructure can continue to be classified under ABS Rules for MODU.
4.2
Temperature and Humidity
The following temperature and humidity data was sourced from Ref [1]: General Design Criteria – Vol-II Section 3.0 Project DESIGN CRITERIA GENERAL (Rev 0) Ref [1] 4.2.1
Climatic Conditions
Table 4.1 presents the climatic conditions to be used on the project. Table 4.1– Climatic Conditions Equipment
Condition
Temperature
Humidity
Deg C
%
1
Gas Turbines
Site Rating
36.7
90
2
HVAC
Summer
35.6
68
Monsoon
30
90
Winter
18.3
65
Inside Condition
22 ± 2
50 ± 5
Ambient Max/Min
40 / 16
90
3
All Other Equipment /General
4.3
Deleted
4.4
Deleted
4.5
MOPU Location and Orientation
The MOPU will be located adjacent to WHP in the WO-16 Mumbai High area of the Company’s operations, off the West coast of India. The coordinates of WO-16 are (Ref [13]): UTM (CM:69) Zone 42:E = 776 299.21 m; N = 2 100 001.69 m. Spheroid WGS-84: LAT 18°58’26.17”N; LONG 71°37’26.53”E The MOPU shall be oriented with stern docking to the south face of the adjoining WHP. 030001910170-GB-001
Page 5 of 31
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Sagar Samrat Conversion Project
Basis of Design
4.6
Water Depth and Chart Datum Level
The water depth for the MOPU at WO-16 is 75.1m, relative to Chart Datum (Ref [12]). All elevations shall be referenced to Chart Datum (0.00m). Chart Datum for Indian water shall be 2.51m below Mean Sea Level (MSL).
4.7
MOPU Hull Elevation
Minimum Elevation of underside hull of the MOPU in operational mode shall be 15.4m (50.5 ft) above Chart Datum, in compliance with Noble Denton Location Review (Ref [12]).
4.8
Soil Borings and Leg Penetration
The MOPU will be initially located at the WO-16 WHP. The ability of the MOPU to operate at any proposed future locations will depend on the location water depth and leg penetration into the supporting soil, subject to the constraints of minimum hull elevation. At WO-16, water depth has been measured at 75.1m (Ref [12]). Soil investigations have been made to allow estimates of MOPU leg penetration to be made and hence the suitability of the MOPU to operate at that site (Ref [13]). After reviewing this report, GL Noble Denton has estimated Sagar Samrat leg spudcan penetration at WO-16 to be 4m (Ref [12]).
4.9
WHP Configuration
For WO-16, orientation of WHP will be assumed with Platform North oriented at True North. WO16 Basic Engineering Main Deck Elevation is (+) 23.15m above Chart Datum (Ref [14]).
4.10
MOPU – WHP Interface
The MOPU will be connected to the south face of WO-16 by means of a retractable bridge which shall support a walkway for personnel access. Target clearance to WHP topside for MOPU docking shall be 18m. Connecting bridge shall be pin-supported at the MOPU end to allow the bridge to be retracted from the WHP by raising from horizontal to vertical or by slewing 90°. A gangway or ramp will connect the end of the bridge with the main deck of the WHP. Final design developed in the detailed design phase, shall permit bridge to be readily disconnected from WHP. For design requirements refer to Ref [15].
4.11
MOPU to WHP Docking
Studies for docking of the MOPU to typical WHP’s shall allow for the Company’s requirement for 18m target clearance between MOPU and WHP. Preferred method of vessel manoeuvring and location control is by tug boats rather than by anchors. Refer to Ref. [15] for further details. 030001910170-GB-001
Page 6 of 31
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Sagar Samrat Conversion Project
Basis of Design
4.12
Jacking System and Legs
Assessment studies on the Sagar Samrat legs and jacking system capabilities shall be based on site inspections, ABS Class Survey Reports and Noble Denton Rig Move Reports as provided by the Company.
4.13
Life Saving Facilities
Life saving, escape, first aid and rescue facilities on the MOPU and WO-16 WHP shall comply with the requirements of the Reference Documents and HSE Studies conducted during the detailed design phase. Extensive fitness-for-purpose assessments of existing MODU equipment and systems above shall be completed to determine their suitability for reuse on the MOPU.
4.14
Fire and Blast Protection
Active and passive fire and blast protection for the MOPU and WO-16 WHP shall comply with the requirements of the reference documents and HSE Studies conducted during the detailed design phase. Dedicated fire pumps (2 x 100%) will be required, drawing water directly from the sea. The Contractor shall consider three fire pump options during the detailed design phase: •
Diesel engine driver and shaft-driven submersible pump inside a caisson;
•
Electric submersible pump inside a caisson, powered by a dedicated diesel generator;
•
Reel type electric submersible pump with flexible discharge pipe, powered by a dedicated diesel generator. In this option, no pump caisson is required.
For all options, each diesel engine shall be air-started and have a dedicated start air storage vessel adjacent and other requirements as per the Reference Documents.
030001910170-GB-001
Page 7 of 31
Rev. C
Sagar Samrat Conversion Project
Basis of Design
5.0
PROCESS FACILITIES DESIGN BASIS
5.1
Design Life
The nominal design life of the new MOPU process facilities will be 25 years. Conversion of the vessel should have the objective of achieving a design life of 25 years while operating as a MOPU. This design life may be achieved through implementation of an appropriate dry-docking and survey program complying with ABS class requirements.
5.2
Well Fluid Arrival Conditions
Arrival conditions are shown in Table 5.1 as follows. Table 5.1 – Well Fluid Arrival Conditions Arrival Temperature (ºC)
40 – 45
Arrival Pressure (barg)
9 – 10 (Note 1, 2, 3 & 4)
Notes: 1.
kg/cm² as pressure unit (1kg/cm² = 0.981 barg). Due to the insignificant difference between the two units, this document makes no difference between them and treats them as interchangeable.
2.
This pressure is to be used in all phases of the design life of the facility.
3.
For process design, the inlet separator pressure is to be fixed at 8 barg.
4.
In future, the inlet pressure to the first stage of the export compression trains may vary between 6.5 barg and 8 barg depending on the MOPU deployment location.
5.3
Well Fluid Compositions
The Sagar Samrat MOPU will receive well fluids from a number of different fields in the WO-16 cluster over the projected field life of 6 years. Only partial wellstream compositions were made available for the Project and so the inlet wellstream compositions were obtained by mixing a number of the known streams to obtain the correct gas-oil ratios for the design cases. The well fluid composition used to represent the oil producing fields has been sourced from the MHN field data, which is given in Table 5.2 below. Table 5.2 – MHN Field Composition
030001910170-GB-001
Component
Mole %
N2
1.16
CO2
3.00
H2 S
0.023
C1
69.994 Page 8 of 31
Rev. C
Sagar Samrat Conversion Project
Basis of Design Component
Mole %
C2
5.866
C3
4.409
IC4
0.879
NC4
1.064
IC5
0.197
NC5
0.169
C6
0.089
CUT-1
2.093
CUT-2
0.639
CUT-3
1.873
CUT-4
1.086
CUT-5
1.174
CUT-6
0.973
CUT-7
0.657
CUT-8
0.968
CUT-9
0.773
CUT-10
0.633
CUT-11
0.401
CUT-12
1.880
The above composition results in an oil gravity of approx 39° API which is similar to many of the actual oil producing fields. In early field life free gas is produced from the B-121 and WO-15 fields and this composition has been sourced from the B-121-2 well data, which is given in Table 5.3 below. Table 5.3 – Well Fluid Composition (Dry Basis)
030001910170-GB-001
Component
Mole %
Nitrogen
0.76%
CO2
2.46%
Methane
89.49%
Ethane
4.22%
Propane
1.76%
i-Butane
0.32%
n-Butane
0.44%
i-Pentane
0.13%
n-Pentane
0.14%
n-Hexane
0.25%
C7+*
0.03%
Page 9 of 31
Rev. C
Sagar Samrat Conversion Project
Basis of Design In later field life, free and associated gas from the WO-16 fields increases and this has a higher CO2 content and this composition has been sourced from the WO-16-1 well data, which is given in Table 5.4 below. Table 5.4 – WO-16-1 Composition Component
Mole %
Nitrogen
0.74%
CO2
13.32%
Methane
75.72%
Ethane
5.67%
Propane
2.67%
i-Butane
0.59%
n-Butane
0.76%
i-Pentane
0.22%
n-Pentane
0.21%
n-Hexane
0.10%
C7+*
0.00%
To model the overall stream composition for process simulation, the above streams were mixed to obtain the oil and gas rates shown below in Table 5.5. A stream of H2S was also added to adjust the concentration to the specified content. CO2 content was also adjusted for case 2 to obtain a case with maximum CO2 content.
Table 5.5 – Design Cases for Process Simulation Design Case
Oil Rate (bopd)
Gas Rate (MMSCMD)
H2S (ppm)
CO2 (Mol %)
Early Field Life (Case 1)
20,000
2.36
1200
2.93
Late Field Life (Case 2)
5,000
2.36
1200
13.00
The resulting inlet stream compositions are shown below in Table 5.6
Table 5.6 – Overall Composition for Process Simulation (dry basis) Case
Case 1
Component
Case 2 Mole %
N2
0.74
0.74
CO2
2.60
12.63
H2S
0.11
0.12
C1
73.74
72.14
C2
4.88
5.63
C3
3.25
2.99
030001910170-GB-001
Page 10 of 31
Rev. C
Sagar Samrat Conversion Project
Basis of Design Case
Case 1
Case 2
Component
Mole %
IC4
0.69
0.66
NC4
0.90
0.85
IC5
0.21
0.23
NC5
0.20
0.21
C6
0.21
0.11
CUT-1
1.49
0.46
CUT-2
0.50
0.15
CUT-3
1.62
0.48
CUT-4
1.00
0.30
CUT-5
1.15
0.34
CUT-6
0.99
0.29
CUT-7
0.69
0.20
CUT-8
1.03
0.30
CUT-9
0.83
0.24
CUT-10
0.69
0.20
CUT-11
0.44
0.13
CUT-12
2.05
0.60
Hypothetical Component properties used in the Hysys process simulation are shown below in Table 5.7
Table 5.7 – Hypothetical Components Hypothetical Component
NBP (°C)
MW
Liq Density (kg/m3)
CUT-1
40.0
75.66
645.0
CUT-2
65.0
84.74
702.0
CUT-3
95.0
99.15
767.0
CUT-4
125.0
117.3
778.0
CUT-5
155.0
135.3
796.0
CUT-6
185.0
156.3
799.0
CUT-7
215.0
179.1
801.0
CUT-8
245.0
198.7
840.0
CUT-9
275.0
224.5
848.0
CUT-10
305.0
251.3
862.0
CUT-11
335.0
282.7
863.0
CUT-12
465.0
438.3
888.0
030001910170-GB-001
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Rev. C
Sagar Samrat Conversion Project
Basis of Design 5.4
Equipment Availability
The overall equipment availability target is 95%, however the actual figure shall be determined during the detailed design phase using a RAM study.
5.5
Production Profile
The following production profile for the WO-16 group of fields is shown below in Table 5.8. Table 5.8 – WO-16 field production profile Year
Oil (BOPD)
Assoc gas (MMSCMD)
Water (BWPD)
Free gas (MMSCMD)
Condensate (BCPD)
1
16475
0.305
0
1.539
1541
2
13725
0.848
21
1.514
1519
3
9250
1.159
23
1.188
1226
4
6900
1.262
15
0.934
997
5
5800
1.510
9
0.567
603
6
-
-
-
2.321
392
5.6
Process Design Specification
The process design specification is depicted in Table 5.9 below. Table 5.9 – Process Design Condition and Specification Maximum Total Liquids (BPD)
30,000 (Note 1)
Maximum Total Oil (BPD oil)
20,000
Export Oil RVP specification
None (Note 2)
Export Oil BS&W specification
1.0% max
Maximum Export Gas (MMSCMD)
2.36
Export gas moisture specification (mg/Sm³)
112.1 max
Maximum H2S Gas Concentration (ppm)
1200
Maximum CO2 Concentration (mol %)
13
Water Processing Capacity (BPD)
0 (Note 1)
Produced Water Specification (ppmw dispersed oil in water)
20
Maximum Export Compressor Discharge Pressure (kPag)
11770
Maximum Oil Export Pump Discharge pressure (kPag)
5300
Inlet Separator Pressure (kPag)
800
Note 1: Produced water rates are expected to be very low and will not require initial installation of produced water treatment unit. The oil processing separators are to be designed for a future produced water rate of 10,000 bwpd, with preheating to give an operating temperature of 60°C in the 3 phase separator, to allow the water treatment equipment to be added in the future if required. 030001910170-GB-001
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Sagar Samrat Conversion Project
Basis of Design Note 2: Un-stabilised oil is to be exported from the 3 phase separator vessel operating at 350 kPag maximum pressure.
5.7
Process Description
The incoming production from the WO-16 wellhead platform contains up to 2.36 MMSCMD gas and 20,000 BPD of oil with up to 1,200 ppm H2S and 13 mol% CO2. The process facilities are designed to separate the incoming stream into oil and gas streams and then treat them to allow pipeline export of the two products via the WO-16 wellhead platform. 5.7.1
Gas Treatment
The gas processing facilities comprise of an inlet separator to provide an initial separation of gas, and oil streams. The gas stream will be directed into the two parallel gas compression trains, each with a design capacity of 1.18 MMSCMD with a TEG gas dehydration unit to remove the remaining water from the gas stream. The gas dehydration unit is to be located in between the 2nd and 3rd stages of compression – this is at a high enough pressure to minimise the water load on the unit but will reduce the absorption of CO2 into the TEG stream. The export of wet gas will cause severe corrosion to the pipeline, therefore it is vital to have a dehydration unit to dry the sour gas to minimise the corrosion to the export pipeline. The 2 x 50% gas compressor train is designed to increase the processing facility availability. In case where one compressor train is offline, Sagar Samrat can still have at least 50% of the production capacity. 5.7.2
Oil Processing
The oil treatment system comprises of an inlet two phase separator to provide an initial separation of the gas and oil streams and provide a surge capacity for incoming liquid slugs. The oil stream is then passed to a three phase separator operating at 3.5 barg where any small amounts of produced water are separated from the oil and then passed to the treated water caisson for further treatment and discharge to the environment. While little or no produced water is expected for the WO-16 group of fields, both the inlet separator and 3 phase separator are to be sized for a produced water rate of 10,000 bwpd and heating to 60°C in between the inlet and 3 phase separators. This will allow a produced water treatment unit and heating system to be added in the future if required. The treated oil stream is then sent to the WO-16 wellhead platform using the oil booster and oil export pumps and exported via an oil pipeline. A small amount of gas flashes off in the 3 phase separator and this is compressed using a small oil-flooded screw compressor and combined with gas from the inlet separator for further compression. 5.7.3
Flare System
The flare system will be designed to handle relief/vent flows arising from the following: •
Process flaring during normal operating modes if required, including start-up and process upset conditions;
•
Emergency flaring caused by emergency depressurisation (blowdown) of equipment;
•
Emergency relief flows to prevent overpressure;
030001910170-GB-001
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Sagar Samrat Conversion Project
Basis of Design •
Manual depressurisation of equipment, e.g. for maintenance.
A single flare tower is to be installed at the No. 3 Jackhouse for the Sagar Samrat, on a 60° angle away from the MOPU. The design shall ensure that the maximum total thermal radiation (including solar) will be less than 4.73 kW/m² at the nearest location where personnel are likely to be present, irrespective of wind direction. This complies with the pain threshold of 16 seconds for bare exposed skin according to API STD 521 (2007) Table 8, and the 2 – 3 minute exposure limit with appropriate PPE according to API STD 521 (2007) Table 9. The relief facilities will consist of the following: 5.7.3.1
HP Flare System
In general, the HP flare system receives relief/vent flows from equipment with a design pressure greater than 1,000 kPag. Maximum back pressure for the HP flare shall be 4 barg. The system consists of a relief header discharging into an HP flare knock-out drum connected via a riser to an HP flare sonic tip. 5.7.3.2
LP Flare System
The LP flare system receives relief/vent flows from low pressure equipment which can only tolerate low backpressures. Maximum back pressure for the LP flare shall be 0.2 barg. The system consists of a relief header discharging to an LP Flare knockout drum connected via a riser to an LP flare sub-sonic flare tip. The LP flare drum is also used as the closed drains collection vessel. 5.7.4 5.7.4.1
Fuel Gas System
Fuel Gas
Fuel gas is used to supply the export gas compressor and power generation gas turbines and other miscellaneous users. Fuel gas will be taken downstream of dehydration (TEG) unit so as to avoid hydrate formation after pressure letdown. While the fuel gas will normally be above the dew point, a KO drum will be provided for process reliability and to provide buffer volume. 5.7.4.2
System Design
Fuel gas system will comprise a high pressure (HP) and a low pressure (LP) fuel gas system. Both HP and LP gas will be delivered at a minimum of 10 deg C. The HP fuel gas system will deliver gas to the gas turbines. The LP system will deliver fuel gas for purge gas, etc. Each system shall be sized for maximum usage case with a 10% margin on flow. 5.7.4.3
Start-up Fuel gas
Due to the pressure requirement for fuel gas to the gas turbines, a start-up fuel gas compressor shall be provided. The start-up fuel gas will be taken from the inlet separator. Once the export gas compressor is running, the start-up compressor will be turned off, allowing the use of continuous fuel gas supply from downstream of the dehydration unit.
030001910170-GB-001
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Sagar Samrat Conversion Project
Basis of Design 5.7.5
Nitrogen
Normally, nitrogen usage is expected to be intermittent and required only for purging equipment for maintenance purposes. A nitrogen generator of about 20 Sm3/h and a nitrogen receiver with distribution system will be provided for this purpose. Nitrogen will also be required as Dry Gas Seal Separation Gas for the compressors and blanketing for thermal fluid expansion tanks. 5.7.6
Instrument Air
Instrument air is required continuously for the instrument control system, and will be supplied from a single package, having 2 x 100% capacity compressors and driers to supply the entire process facility requirements, comprising but not limited to the following. •
2 x Air compressors (100% capacity);
•
2 x Dryer pre-filters stage 1;
•
2 x Dryer pre-filters stage 2;
•
2 x Air dryers;
•
2 x Air dryer after filters;
•
2 x Dewpoint analyser (one per dryer unit);
•
1 x Air receiver.
Capacity of each unit within the package will be between 50-200 m3/h, depending on the final process design and the number of individual equipment items. The existing air compressors will be reviewed for suitability. 5.7.7
Chemical Injection
All chemicals will be stored in full strength storage tanks based on 15 days requirement at normal rates or Drum equivalent to 30 days normal consumption. Each chemical shall be stored in the open area. The following chemical requirements have been identified: 5.7.7.1
Corrosion inhibitor
Corrosion inhibitors (CI) are used to reduce the corrosive effects of acid on metal surfaces usually by forming a film on the metal surface. Typical injection rate is about 30-60 ppmw for oil stream and 10-20 litres per MMSCM for gas at each location. NORSOK Standard M-001 Section 4.2.2 states “use of corrosion inhibitors in topsides process systems is not recommended”. This is due to high H2S and CO2 concentration, and difficulty transporting corrosion inhibitors to all areas of internal piping and equipment. Where possible, CRA will be used for most process piping; vessels will be either CRA or CRA lined. For this reason, CI will only be injected downstream of the gas dehydration unit in case off specification gas has to be sent to the export gas pipeline. 5.7.7.2
Demulsifier
The oil from the WO-16 field group is predicted to contain only small amounts of produced water. Emulsion stability is affected by size of water droplets dispersed in the oil as well as water salinity. 030001910170-GB-001
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Basis of Design Heating the emulsion can reduce the amount of treatment chemical required. Typical demulsifier dosage is about 300 ppmw to total fluid at each injection point. The designed injection points for the Project are: •
Upstream of inlet separator;
•
Upstream of three phase separator;
5.7.7.3
Pour Point Depressant (PPD)
The incoming well fluid stream to Sagar Samrat contains high proportions of waxy oil. Due to changing temperature and pressure conditions, hydrocarbon solids may deposit on the walls of equipment or pipeline. These deposits generally consist of straight and branched chain hydrocarbons and are commonly referred to as paraffins or wax. Pour Point Depressant (PPD) may be required to lower the incoming well fluid pour point to prevent potential wax deposition. Typical PPD injection rate is about 300-600 ppmw at each point. The preferred injection points are all upstream of the three-phase separator and/or downstream of the export oil pumps. Detailed data for the condensate pour point is currently unavailable, but will be required to assess the requirements and optimal location for PPD injection. 5.7.8
Diesel Storage and Distribution
Diesel will be required intermittently on the Sagar Samrat for: •
Emergency power generation;
•
Main power generation;
•
Emergency air compressor;
•
Survival craft;
•
Cranes;
•
Firewater pumps.
Diesel will be delivered to Sagar Samrat by supply vessel as required. The diesel storage requirements will be calculated to ensure that the emergency generator can run for 28 days without diesel interruption. 5.7.9
Open Drains System
The open drains system will collect oily water from the deck drains and process area drains in hazardous and non-hazardous areas. For sizing of the drain system, the following shall apply: •
The minimum velocity to avoid deposition of solids = 0.9 m/s;
•
Drain headers operate half full at maximum flow, with minimum size of 100 mm;
•
Firewater deluge will be excluded from the sizing calculations.
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Basis of Design 5.7.10 Closed Drains System The closed drains flows will be collected from the process vessels. The system will be run as separate pressure rated headers up to Low Pressure Flare Knock Out Drum (LP FKOD) inlet nozzle. The lines feeding the header will utilise positive isolation to prevent inadvertent opening of valves. The closed drains lines and header will gravity drain to the LP FKOD wherever possible. If, for layout reasons it is not possible to gravity drain the closed drains lines and header, the design will consider alternative drainage methods e.g. using nitrogen, process pressurisation or pump-out.
5.8
Supporting Steelwork
Steelwork, supporting and ancillary to process equipment, including flare tower shall be designed generally in accordance with ONGC’s Design Criteria (Ref [2] & [3]). Design loading shall include as a minimum: •
Operation dead and live load static and dynamic;
•
Environmental loads including wind and earthquake;
•
Transportation loads
Environmental data is described in Section 6.5.
5.9
Piping design 5.9.1
General
Piping design shall be in accordance with ONGC-Piping design criteria-3.3 & functional specification FS2004A. 5.9.2
Piping Flexibility Analysis
For certain operating conditions, flexibility analysis shall be used to determine stress levels, support loads, loads on connected equipment and displacement. Sufficient piping flexibility shall be maintained to meet the equipment allowable nozzle loads as specified by vendors. Guidelines for identifying when flexibility analysis shall be carried out are as follows: •
2” and larger, temperature range >260oC;
•
4” and larger, temperature range >205oC;
•
8” and larger, temperature range >150oC;
•
12” and larger, temperature range >90oC;
•
All 3” and larger connected to rotating equipment;
•
All 4” and larger connected to air coolers (box type headers);
•
All 6” and larger connected to tanks.
Flexibility analysis shall be carried out using recognised software such as CAESAR or Autopipe. 030001910170-GB-001
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Basis of Design 5.9.3
Valves
All operational valves, strainers and instrumentation shall be accessible from deck level, otherwise access platforms shall be provided. Valves shall be specified in accordance with the Reference Documents. Valves shall be adequately supported. Valve location shall consider typical operator / actuator dimensions, and access for maintenance. Double block-and-bleed valves shall be used for isolation of equipment that requires regular inspection and maintenance. Typically, this will include: •
Sand cleaning systems and sand traps;
•
Process pumps;
•
Closed drain pumps;
•
Flare pumps;
•
Isolation between oil process and gas compression facilities.
All valves shall be capable of being locked in the open or closed position with a positive position locking device other than chain. Block valves shall in general be ball valves, and of fire-safe design. Where pressure drop in the system is not a consideration, positive sealing type butterfly valves may also be used as block valves. Butterfly valves may be used in cooling water services. Valves shall be provided with pressure equalising bypasses when high differential pressure exists across the closed valve. Valves for which bypasses are to be furnished and the size and type of bypass valve will be shown on the applicable flow diagram. Globe valve shall be used where throttling or control is required.
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Basis of Design
6.0
MOPU DESIGN BASIS
The gas, oil processing and waste water treatment facilities, will all be designed with a minimum turndown of 50%.
6.1
Topsides Configuration
The topsides facilities shall be supported by the MOPU hull framing (ie bulkheads, frames, stringers). Local reinforcement of the hull framing shall be added where required. The design of all topsides framing and hull reinforcement shall be conducted in the detailed design phase.
6.2
Helicopter Refuelling
The helicopter refuelling system shall consist of the following new equipment:
6.3
•
Storage tank;
•
Fuel pump(s);
•
Filter/water separator(s);
•
Air eliminator(s);
•
Hose reel with filling nozzle;
•
Earthing system;
•
Flowmeter.
Electrical Design 6.3.1
General
The existing MODU power system is based on NEC code being 460 (440)/120Vac 60hz with the main power users (draw-works 2,000 hp & mud pumps 1,500 hp x 2) and jacking system being powered by four DC generators. All existing power systems remaining after conversion will be supplied from the new electrical power system and be modified as required to accept the new voltage and frequency as required. The new electrical power supply and distribution system for the new process production and utility equipment shall be designed in accordance to the IEC codes and standard except as otherwise specified. The nominal voltage utilisation levels shall be as follows:
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Basis of Design Utilisation Voltage
Loads
6.6kV AC, 3Φ, 50Hz
For motors rated 150kW and above
415V AC, 3Φ, 50Hz
For motors rated at 0.37 up to 150kW, Battery Chargers, UPS, HVAC, Bulk AC loads
240V AC, 1Φ, 50Hz
For motors rated below 0.37kW, Communications system, Radio Equipment, Anti-condensation space heaters, Convenience outlets, General and Level gauge illumination
110V DC, 2wire
Critical Lighting, Switchgear & Generator Controls, DC for emergency lube oil pumps, etc
24V DC, 2wire
Instrument supply, Fire & Gas detection system
12V DC, 2wire
Navigation Aids System
240 AC, 1Φ, 50Hz UPS
Distributed Control System, EPAX, CCTV system, Radio system, Paging and Intercom system, Telemetry, telecom and computer system
6.3.2
Main Power
The main power generation shall be provided by two 100% Dual Fuel Gas Turbine Generators rated to supply the complete MOPU power load at 6.6kV, 50Hz. Existing MODU loads that remain after conversion will be modified to accept the new 50Hz power system. Refer to SLD’s.
6.3.3
Emergency Power
A single 100% diesel engine driven 415V, 50Hz emergency generator rated to supply the MOPU emergency and essential power loads shall be provided. During emergency (power outage of main GTG/s) the emergency generator shall supply power to the Emergency Switchboard and connected Essential Loads. 6.3.4
Power Distribution System
The distribution of main AC power shall be at 6.6kV, 415V and 240V. All HV loads shall be fed from the HV switchgear. The HV switchboard shall be split bus type with bus coupler for improved reliability. Two 100% step down 6.6kV/415V transformers shall be provided for LV equipment loads via the LV Switchboard. The LV switchboards shall be split bus type fed from separate transformers for reliability. The LV switchboard will feed the Emergency Switchboard. LV Distribution Boards (DB) shall be provided for various small process and utility loads. These DBs shall be fed from a main draw out type LV switchgear on either the LV or Emergency Switchboards. Distribution Panels 415/240V shall be provided for normal lighting, space heaters, etc as required. These shall be supplied from main LV 030001910170-GB-001
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Basis of Design Emergency and essential loads shall be connected to the emergency switchboard. 6.3.5
DC Systems
Separate battery banks with battery chargers shall be provided for 110V, 24V & 12V DC systems to meet all the DC power requirements of critical loads for the new production and utility equipment. All battery banks shall have a 10% spare capacity to meet future load growth. 6.3.6
UPS Systems
Dual UPS systems (80 kVA 415 / 240 VAC) shall be provided to meet the requirements for 240VAC UPS loads. The UPS system shall have 10% spare capacity to meet future load growth. 6.3.7
Transformers
Two by 100% step-down transformers (2,000 kVA, 6.6kV/430V) shall be provided to supply the LV switchboard. The transformers shall be cast resin dry type, rated for continuous duty, vector group Dy11. 6.3.8
Electrical Loads
Load calculations based on preliminary equipment list in conjunction with typical other loads for standard packages (excluding marine loads) plus a 25% allowance for load growth during detailed design will be used to determine the normal production demand and the peak production demand. The generation unit shall be sized on the basis of the peak production demand as per the Process Design Criteria listed in Table 5.9. Electrical loads are to be categorised into Continuous, Intermittent or Standby dependent on utilisation. Intermittent loads shall have a load factor applied to determine normal demand. 6.3.9
Operating Philosophy
The 2 x 100% GTGs will be run in on a Main/Standby basis. During non-availability of a GTG (due to planned or unplanned shutdown of one unit) the remaining unit shall be capable of meeting the peak power requirement of the new process production and utility equipment to maintain full operations. Step-down transformers shall be sized for their total load requirement. Normally the transformers shall operate independently, but it will be possible to momentarily parallel transformers during transfer of loads between transformers. The HV switchboard will normally be operated with bus coupler closed. LV switchboards will normally be operated with bus couplers open. A power system availability of >98% is required on the basis of equipment availability of >99%. The electrical system design and plant selection will be designed to ensure this is met. 6.3.10 Hazardous Area Classification and Determination The process areas on the lower equipment level and the upper equipment level shall be classified based on API 505, 1st edition November 2007; the Contractor shall prepare hazardous area classification determination schedules and drawings during the detail design phase of the project. The indicative hazardous area classification for this area is Class I Zone 2 IIA T3 for a radius of 030001910170-GB-001
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Basis of Design 3m; except for areas with poor ventilation or areas surrounding vents, where the hazardous area classification will be additionally Class I Zone 1 IIA T3 for a radius of 1.5m. The areas surrounding the equipment detailed below require stringent assessment: •
In addition to the Zone 1 requirements for the area surrounding the gas compressor enclosures, the area surrounding the gas compressor seal vents will be classified as Class 1 Zone 0 IIA T3 for a radius of 0.5m. This situation is consistent with the majority of vents.
•
The area on the lower equipment level directly under the upper equipment level will have compromised ventilation; hence, requires a more onerous classification of Zone 1.
•
In general, deck drains are only Zone 1 within the containment area since they are designed to contain flammable liquids for brief periods. In addition, a Zone 2 area of only 0.5m is applicable to these cases, as long as the area is well ventilated.
Enclosed rooms (or areas) which are pressurised shall be regarded as non-hazardous. All field instruments and electrical equipment located in the lower and upper equipment levels shall be certified to Zone 2 IIA T3 as a minimum. Since the lower deck is pressurised, general purpose equipment may be installed in this area unless the operation of the equipment is imperative when this area loses pressurisation.
6.4
Instrumentation Design 6.4.1
General
The existing MODU has an existing Techtronic’s F&G panel which is in a poor condition. The existing quarters are fitted with smoke detectors only. The control systems associated with the derrick will be dismantled when this is demolished. The existing control equipment for operation of the jack-up legs and any existing barge utilities will remain in place and be refurbished as required to ensure 25 year life. Existing F&G panels shall be discarded. Living quarters shall be fitted with new smoke and heat detectors. Cabling shall be new and shall be included in scope for re furbishing the building module. 6.4.2
Integrated Control System
An Integrated Control System (ICS) will be used to control and monitor all new process and utility equipment from a new Central Control Room (CCR). A new Equipment Room will be provided complete with Engineering Work Station (EWS) for each system. Local manual ESD stations will be located at convenient locations around the process and utility areas for emergency shutdown purposes. Refer to Integrated Control System Architecture drawing (030001910170-JD-001). The ICS components (HMI, PCS, ESD, F&G) across the facility shall be linked by a dual redundant copper control network. The ICS will have Human Machine Interface (HMI) consisting of PC based graphical displays (Operator Stations) and hardwired Critical Control Panel (CCP). The process control system (PCS) will be DCS based with the independent ESD and F&G using a high reliability PLC suitable for the safety integrity level (SIL) safety requirement of the facility. Each of 030001910170-GB-001
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Basis of Design the PCS, ESD, & F&G systems will be provided with its own HMI, and the same will be integrated on real time with the ICS. All packaged unit control panels will be provided with their own HMI for configuring and monitoring critical parameters of all packaged equipment units. Where specified, remote control panels will be provided in CCR. The ICS operating system will include, graphical interface display software, engineering facilities, database and process data history modules and redundant network servers suitable for the facility requirements including future expansion and tie-in of remote Well Head Platforms via cable based network. The HMI Operator Station graphics will be developed in a simple and intuitive format with provision for operator training in HMI operation, process operation and system functionality. HMI Operator Station shall be with twin monitors (LCD / LED monitors) & with open type consoles. Three dual screen consoles shall be provided. Additionally separate (single monitor) EWS (Engineering work station) shall be provided for each of the PCS, ESD and F&G, and be located in the Equipment Room. The ICS will interface with the PA system to broadcast emergency alarms, and with the data network to allow non-critical data to be displayed on the HMI Operator Stations. Emergency Shutdown interfaces between the PCS, ESD and F&G panels will be via monitored, redundant hardwired relay interconnection. The PCS, ESD and F&G shall share one EWS, which will be segregated into two (20 independent sections (1 for PCS & 1 for ESD & F&G). 6.4.3
OLE for Process Control (OPC)
The ICS shall have a server comprising OPC (OLE for Process Control) interface between ICS and SCADA (Supervisory Control And Data Acquisition) for read/writing of data between an application of third party OPC client and the ICS, for specified event and alarm condition in the ICS and to enable read, process and edit data of the historian engine of ICS. Supervisory control and data acquisition between the MOPU and Wellhead platforms, cable connection or SCADA system shall be utilised. 6.4.4
Control Room, Equipment Room and Instrument Laboratory
The Central Control Room, Equipment room and Instrument Laboratory will be provided with HVAC and be in accordance with Company specifications. 6.4.5
Fire and Gas Detection System
Fire and gas detection systems will be provided covering all new process and utility production equipment as appropriate. In general, the F&G system shall be supplied with a floating power supply. The UPS shall have a switching mechanism to ensure supply to the F&G system. F&G detectors shall be as per the relevant functional specifications. F&G system (Detectors and Panel) shall be “new” and shall be considered for entire MOPU. Existing equipment shall be removed / demolished appropriately. 6.4.6
Toxic Gas Detection
Fixed H2S gas detecting shall use electrochemical cell technology. 030001910170-GB-001
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Basis of Design A new system shall replace the existing MODU Fire & Gas panel. Existing detectors may only be used if compatible with the new F&G system. 6.4.7
General Instruments
Instruments will be “smart” transmitter type capable of reconfiguration from the CCR ICS. The use of intrinsically safe transmitters is preferred, that is Ex ia or Ex ib. Unless otherwise specified or required, Ex e certified Junction boxes and marshalling boxes shall be used. All instrumentation shall be new. Where the equipment is retained and has its integral instrumentation, the instrumentation shall be refurbished only if serviceable. However, it shall be ensured that the connectivity to DCS shall be established. New instrumentation shall be preferred in case of doubts on the use or serviceability of the existing instrumentation. All process transmitters shall be smart (with HART) and designated with tag “PZT, TZT, LZT, etc”, when used for trips and shutdowns. All shutdown and trips to valves, systems and equipment shall be hardwired. Serial links shall be used for integrating all field/packaged equipment with PLC/electronic control with the DCS. Where no serial links are possible, the signals shall be suitably ‘hardwire interfaced’ to the PCS for analog/digital/status signals. Refer to Instrumentation Design Criteria / Functional specification 3103, 3302 and 3403. 6.4.8
Control Network
The determinate control network will provide facility control monitoring, fire & gas and shutdown data via a twisted pair cable network. Control network shall be dual redundant Control network shall be dual redundant as specified in the ICS specifications. F&G & ESD systems shall be independent of the PCS. F&G and ESD may be integrated to the PCS on the control network / data highway; however, the ESD and F&G are segregated from the same unit. 6.4.9
Metering
All consumables such as diesel, fuel gas and chemicals shall be measured and monitored in the PCS, in addition, major consumers of diesel and fuel gas shall have appropriate metering. All inlet and outgoing lines shall have appropriate meters installed on the piping to monitor the flow rates of all fluids and utilities.
6.5
Structural Design
The relevant design data applicable to the design are in accordance with Section 3.4 Design Criteria Structural Part-I and II (Ref. [2] & [3]), except as advised below. 6.5.1
Environmental Data
The environmental data are documented in Section 7.0 Environmental Data Tables.
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Basis of Design 6.5.2
Fatigue analysis
The methodology and environmental data as specified in the design criteria shall be used to evaluate fatigue integrity for Sagar Samrat hull, legs and jacking system complying to ABS guidelines 6.5.3
Earthquake Loads
As per Indian seismic regulation the MOPU will be located in earthquake category zone IV and shall be subject to the acceleration spectra prescribed by Indian Standard IS-1893. Earthquake analysis of the MOPU and facilities shall be conducted in the detailed design phase to enable compliance to Classification Society Rules. The earthquake loading on the combined vessel and super structure shall be calculated using the response spectrum method and in accordance with the provisions of API RP 2A. The response spectrum data for this analysis shall follow the guidelines for Zone-IV earthquake area as given in Indian Standards IS-1893. The importance factor shall be taken as 2.0 and response spectra Type III to be considered to account for the soil foundation system. Contribution of the marine growth in the added mass shall be considered in the analysis. For building /equipment/ modules an equivalent static analysis shall be carried out with a horizontal seismic coefficient of 0.12. Earthquake Forces, wherever applicable, shall be taken as occurring in both horizontal directions and 50% in the vertical direction 6.5.4
Helideck Design
The design of the existing helideck is to be assessed against CAP437 and made suitable for the following helicopters: •
Dauphin AS365N3;
•
Augusta/Westland AW139;
•
Bell 412.
Helicopter data are given in Table 6.1. Helideck design criteria are described in Design Criteria (Ref [2] & [3]). Table 6.1 – Static Helicopter Data Detail
Dauphin AS365N3
Augusta/ Westland AW 139
Bell 412
Maximum Weight (kg)
4300
6400
5400
Helideck “t” Marking
4.3 t
6.4 t
5.4 t
Main Rotor Diameter (m)
11.94
13.8
14.02
Maximum Length / D-Value (m)
13.73
16.66
17.13
14
17
17
Helideck “D” marking
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Basis of Design
7.0
ENVIRONMENTAL DATA TABLES
Refer to Table 7.1 to Table 7.4
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Basis of Design Table 7.1 – Operating Storm Parameters Direction (From) *
All Direction
Tide
Maximum Wave
Current
Wind
AT
Storm
Height
Period
Bottom
Y-¼
Y-½
Y-¾
Surface
1-Hour Average
(m)
(m)
(m)
(sec)
(m/sec)
(m/sec)
(m/sec)
(m/sec)
(m/sec)
(Km/h)
3.26
0.61
11.583
11.00
0.476
0.878
1.049
1.22
1.387
99.22
Lowest Astronomical Tide (LAT)
: (-) 0.183 m
* Direction from which current flows, tide and wave approach Note: Data extracted from Ref [10].
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Basis of Design
Table 7.2 – SLR’s For Offshore Bombay Area; All Season 50 Year Extremes Water Depth at Chart Datum (m)
30
40
50
60
70
80
90
1 minute mean (m/s)
46
46
46
46
46
46
46
3 second gusts (m/s)
53
53
53
53
53
53
53
Maximum Individual Wave Height (m)
14.0
15.1
15.6
16.3
17.0
17.2
17.2
Period (crest to crest)
11.4
11.8
12.0
12.3
12.5
12.6
12.6
Length (m)
173.0
195.0
209.0
223.0
236.0
241.0
244.0
Significant Height (m)
8.0
8.6
8.9
9.3
9.7
9.8
9.8
Peak Energy Period (m)
12.4
12.8
13.0
13.3
13.6
13.7
13.7
Wave Crest Elevation (m)
8.7
9.0
9.1
9.3
9.6
9.7
9.6
Tidal Rise at MHWS (m)
3.5
3.4
3.2
2.9
2.8
2.8
2.7
Storm Surge (m)
1.7
1.5
1.4
1.3
1.2
1.2
1.2
Safety Margin – 10% (m)
1.5
1.5
1.5
1.5
1.5
1.5
1.5
Min Air-gap above CD (m)
15.4
15.4
15.2
15.0
15.1
15.2
15.0
Total Surface Current (m/s)
1.5
1.5
1.5
1.5
1.4
1.4
1.4
Wind Speed
Wave Height
Water Levels
Notes: •
The above are the extremes likely to be reached or exceeded once, on average, during a 50 year return period within area 18º - 20º N 71º - 72.5º E (Ref [9])
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Basis of Design Table 7.3 – Wind Speed for Design of Platform (Omni Direction) Item
Type
Design Wind Speed
a
Topside In-place Analysis
1 Min Average
b
Substructure In-place Analysis
1 Hour Average
c
Bridge In-place Analysis
3 Sec Gust
d
Building/Module Frame Analysis
5 Sec Gust
e
Cantilever Structures, towers, vent, flare boom, etc.
3 Sec Gust
f
Exterior wall panels of buildings, fire walls, barrier walls including their stiffeners
3 Sec Gust
g
Structures Greater than 50 m length
15 Sec Gust
Note: Derived from Ref [3], Table 12.
Table 7.4 – Wind Speed for Design of Platform Direction (From which wind blow)
Wind Speed (Km/h) 1 Minute Mean
1 Hour Average
1 Minute Sustained
50-year Extreme Storm
1-year Operating Storm
Installation Condition
All Direction (OMNI)
165.6
99.22
48.27
Data source
Table 7.2 – SLR’s For Offshore Bombay Area; All Season 50 Year Extremes
Environmental Data Tables Table 7.1
Ref [3], Table 7
Notes: 1. The wind speeds are at a reference elevation of + 10.00m above Mean Sea Level (MSL)
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Basis of Design
8.0
ARCHITECTURAL DESIGN
Refurbishment of accommodation facilities shall be in accordance with the requirements specified in the bid complying with specification 6010 to accommodate 72 people overnight.
9.0
WEIGHT CONTROL
Since the vessel will be required to float for towing in a stable configuration during transportation to operational locations, the development of the new equipment layouts on the topsides should achieve a balanced distribution of weights about the hull centerlines and the overall weight of new facilities should be limited to the overall weight of equipment removed during demolition works. Final sail away weights shall always comply with the requirement of the vessel’s “Trim and Stability” booklet Ref [11]).
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Basis of Design
10.0
REFERENCES [1]
General Design Criteria – Vol-II Section 3.0 Project; Design Criteria General (Rev 0)
[2]
Design Criteria Structure - Part IVA Section 3.4 Section 3.4 Design Criteria Structural (Process Platform) Part-I (Ref No. ODS/SOP/004B Rev 01)
[3]
Design Criteria Structure - Section 3.4; Section 3.4 Design Criteria Structural (Process Platform) Part-II
[4]
Electrical Design Criteria
[5]
Instrumentation Design Criteria: VOL-II Spec. No. 3.6 Rev 2 Instrumentation Design Criteria
[6]
American Conference of Industrial Hygienists – TLV Handbook: 1999, Hand-Arm and WholeBody Vibration.
[7]
Guidelines for Drinking Water Quality, Third Edition, Volume 1 – Recommendations, WHO, Geneva, 2004.
[8]
IMO Res A 855(20): 1997, Standard for Onboard Helicopter Facilities.
[9]
SLR’s For Offshore Bombay Area; All Season 50 year Extremes, Location: 18º – 20º (N) 071º th – 071.5º (E), Noble Denton WS: 20/04/3139 Dated 16 June 2006.
[10]
Design Criteria Structure – Part IVA Section 3.4; Annexure I; Corrected Environmental Data contained in email ES/DD/SSCP/DT1/2007 from ONGC 17 April 2007.
[11]
Trim and Stability Booklet of JUR Sagar Samrat (Official No. 1504 of Mumbai) Document No. AB/03-73/02 by AB Marina Consultants, dated December 29, 2003.
[12]
WO-16 Location Review, GL Noble Denton, received in email from ONGC to Mustang 23 Nov 2010.
[13]
On Board Report on Geotechnical Investigation and Foundation Assessment of Jackup Rigs and Platform Foundation at WO-16Location in ONGC’s Mumbai High Field West Coast, Offshore India, Report No. CM 08 09 21-72, 14 April 2010
[14]
Engineers India Limited, Drawing 1155, WO-16 Well Platform Deck Truss Row A and B, Rev A, Job No. A108.
[15]
Sagar Samrat Conversion Project, Docking and Bridge Connection Study, Technical Note, Document No. 030001910170-NB-003.
[16]
Technical queries response received in email from ONGC to Mustang 23 November 2010.
[17]
Sagar Samrat Conversion Project: Process Facilities Definition Report, Document No. 030001910170-PR-001.
030001910170-GB-001
Section 3.5 Section 3.5 Design Criteria (Electrical)
Page 31 of 31
Rev. C
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