info.md

YADANA OPERATING PHYLOSOPHY

1.	General Field Description
  
The operational activities of PTTEP cover a significant area within Myanmar, 
including the following key locations:

-	Yangon: Head office and logistic bases, including marine and air facilities,
-	Yadana Field: Offshore production platforms where gas from the Yadana, Sein, and Badamyar reservoirs is extracted,
-	Onbinkwin Pipeline Centre(PLC),
-	Ban-I-Tong Metering Station (MS)


Important Glossary:(very important)

Name of Platforms in Yadama Asset:
WP1= wellhead platform 1
WP2= wellhead platform 2
WP3= wellhead platform 3 (Sein)
WP4= wellhead platform 4 (Badamyar)
QP2 = QUarter Platform
PP = Producrion Platform
LCP = low compression platform
MCP = Medium Compression Platform
FP= Flare Platform

1.	ESD Levels:
•	ESD Level 0: Abandon installation, initiates a black shutdown.
•	ESD Level 1: General emergency shutdown, closes all ESVs and initiates blow-down.
•	ESD Level 2: General process shutdown, stops production.
•	ESD Level 3: Individual process shutdown.


•	ESD0 initiated automatically on confirmed gas detection or manually with approval.
•	ESD1 initiated by F&G system and push buttons.
•	ESD2 initiated by key safety switches and push buttons.

•	Each platform is equipped with its own ESD system.
•	Connected to the Control Room via hardwire link or telemetry system.
•	PLC used for ESD control, with operator interface and DCS console.

•	Local independent electro-hydraulic panel for shutdown execution.
•	ESD actions can be initiated from the Control Room.

•	Local resetting required on ESVs and SDVs after any ESD level.
•	BDVs can be reset from the Control Room.
•	Partial stroking facilities for ESD Valve Function testing.

•	ESD 0 push buttons hardwired to platform ESD systems.
•	Dedicated HS for blowout disabling during rig operation.
•	Partial stroking facilities for ESV valves for testing purposes.

    Pipeline System:
•	36" pipeline transports gas (domestic and export) to delivery points at PLC and Thai border.
•	Offshore pipeline length: 346 km to coast. (Yadana offshore to Pipeline Centre)
•	Onshore pipeline length: 63 km. ( Pipeline centre to Metering Station)

•	Custody transferred to PTT of Thailand at border.
•	Gas further transported by 238 km long 42" pipeline from Metering station to Ratchaburi where main users are EGAT and TECO Power Plants.

    Pressure Requirements:
•	Required delivery pressure at EGAT power plant: 36.9 bar (550 psia).
•	Contractual delivery pressure at Thai border: Maximum 64.5 bar (950 psia).

    Gas Delivery:
MMSCFD = million standard cubic feet per day
•	Normal domestic gas supply to MOGE at PLC: 50 MMSCFD since June 2010.
•	Maximum export gas delivery to PTT: 720 MMSCFD with border back pressure around 53 barg (780 psig) by running PTT BVW7 compressors.
•	Maximum delivery to PTT recorded around 750 MMSCFD in May 2011.

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1.1. Yadana Development History (Offshore)
1.	Phase 1 (Installation of WP2):
•	Remote wellhead platform (WP2) installed with a 20" subsea production line.
•	Platform complex includes wellhead WP1, production PP, living quarters QP, and flare tripod structures, all bridge linked.
•	Gas exported via a 36" pipeline to the Myanmar/Thai border.
2.	Phase 2 (Addition of WP3):
•	Second remote wellhead platform (WP3) developed in 2005 (Sein field).
•	WP3 equipped with a 10" subsea production line, tied into WP1 production manifold.
•	WP3 consists of two gas-producing wells, with production starting in March 2006.
3.	Phase 3 (Installation of MCP):
•	Medium Compression Platform (MCP) installed approximately 87m NNE of existing Production Platform.
•	MCP tied into PP facilities via 24" 900# duplex lines running to MCP and 18" 900# duplex lines returning from MCP, bridge-linked.
•	MCP installed to compensate for declining reservoir pressure, ensuring required export pressure of sales gas.
4.	Phase 3 (Domestic Gas Demand Facilities):
•	Facilities provided in original design planned for Phase 2, including metering and topsides 20" pigging facilities.
•	Implementation occurred after Phase 3, maintaining existing 20" departure facilities with some modifications.
•	Gas sent to onshore independently of 36" export pipeline via 24" subsea line constructed by MOGE in 2009 and 2010.
•	Existing 20" riser blinded for future tie-in.
5.	Phase 4 (Development of Badamyar):
•	Installation of 4th wellhead platform (WP4) located approximately 8 km from central complex.
•	Installation and hook-up of LP compression, comprising the first compression stage (2x50%).
•	LCP compression platform bridge-linked to MCP with tripod bridge support to reduce structural loading of MCP.
6.	Parallel Projects (2012-2015):
•	Two projects conducted alongside development plan between 2012 and 2015.


1.1.1. Yadana Subsidence Project (2012-2015) 
1.	Replacement of Flare Platform:
•	Due to subsidence, the flare platform (FP) replaced by FP2 located next to MCP.
•	Linked to MCP by a 130m long bridge.
•	FP flare and bridge removed, remaining jacket equipped with navigation lights for safety.
2.	Protection Measures for Drain Decks:
•	Drain decks on PP, MCP, WP1, and WP2 now in splash zone due to subsidence.
•	ESV, SDV, Hydraulic accumulators, and HPU protected by rigid caissons to withstand wave impact.
•	Closed drain drum and sump drum on PP relocated to lower deck out of wave reach.
•	Vertical pipes installed on drain systems to collect fluids and pump to re-route fluids to respective drums for treatment.
•	Condensate injection pumps located on lower deck due to low NPSH available, variable cavity pumps selected.
3.	Platform Modifications:
•	On WP1 & WP2, closed drain drum replaced by vertical pipe with similar function.
•	On WP2, electrical transformer and corrosion inhibitor injection skid relocated to lower deck.
•	Grating and secondary structures of drain deck dismantled on all platforms where wave splashing is highly impacted.
4.	Living Quarter Relocation:
•	Second phase relocated living quarter to new jacket and MSF2 designed for new conditions.
•	New arrangement named QP2, with additional accommodation capacity.
•	"Old" jacket remains in place until decommissioning, fitted with navigation lights for safe navigation.


1.1.2 Seismic Impact Project (2014-2015):
1.	Structural Works:
•	Yadana central complex platforms and bridges underwent necessary modifications due to re-evaluated seismic hazard conditions and new soil data.
•	Structural reinforcement performed on PP, MCP, and WP1 platforms, including dismantling where required on Jacket, MSF, and Topsides.
•	PP-MCP and PP-WP1 bridges modified and reinforced on both sides.
•	Bridge sliding supports installed at MCP and WP1 sides.
2.	Piping Works:
•	Existing flare line sections at PP-MCP bridge (30’’ HP Flare, 12’’ HP Flare) and PP-WP1 bridge (8’’ HP Flare) modified.
•	Tie-ins performed to insert expansion loops, including dismantling scope where required.
•	Expansion joints and associated instrumentation added to flare lines.
•	MCP TC-A/B outlet lines (2x18’’) modified to insert expansion loop, including dismantling scope where required.
•	New supports installed for outlet lines.

1.1.3.	Onshore Facilities:
1.	Pipeline Centre and Metering Station:
•	Includes a Pipeline Centre near Onbinkwin and a remote Metering Station at the Thai border.
•	Domestic gas supply facilities commissioned and started up in 2001 with a design capacity of 20 MMSCFD.
•	Due to high domestic gas demand, delivery increased to maximum limit of 50 MMSCFD.
•	New domestic gas facilities with a design capacity of 110 MMSCFD upgraded, commissioned, and started up since December 2006.
2.	Pipeline System:
•	36" pipeline transports gas (domestic and export) to delivery points at PLC and Thai border.
•	Offshore pipeline length: 346 km to coast.
•	Onshore pipeline length: 63 km.
•	Block valve stations installed at landfall point (BV1) and middle of onshore run (BV2).
•	Custody transferred to PTT of Thailand at border.
•	Gas further transported by 238 km long 42" pipeline to Ratchaburi where main users are EGAT and TECO Power Plants.
3.	Pressure Requirements:
•	Required delivery pressure at EGAT power plant: 36.9 barg (550 psia).
•	Contractual delivery pressure at Thai border: Maximum 64.5 barg (950 psia).
4.	Gas Delivery:
•	Normal domestic gas supply to MOGE at PLC: 50 MMSCFD since June 2010.
•	Maximum export gas delivery to PTT: 720 MMSCFD with border back pressure around 53 barg (780 psig) by running PTT BVW7 compressors.
•	Maximum delivery to PTT recorded around 750 MMSCFD in May 2011.
5.	Pigging Facilities:
•	Pipeline system equipped with pig launching/receiving facilities for conventional or intelligent pigging of offshore sea line and onshore pipeline up to Metering station.
•	42" line pigged from PTT station at Ban-I-Tong (BVW-1) up to Ratchaburi under PTT responsibility.
•	Section between Metering Station and PTT station on other side of border (BVW-1) cannot be pigged.

2.	General Data
 
 
Current:
Surface currents at Yadana are primarily influenced by wind, with a mean speed of 0.4 m/s and possible peaks reaching 2.0 m/s during steady Monsoon winds. However, these currents diminish rapidly with depth, with mean speeds near the seabed at approximately 0.15 m/s. The strongest currents generally originate from the northeast (N/E) and east (E), flowing in parallel with the local bathymetry.

Tidal currents also play a significant role, particularly during spring tides, where maximum currents can reach around 0.5 m/s. These tidal currents flow perpendicular to the local bathymetry, resulting in four flow reversals each day (two floods and two ebbs), corresponding to flow directions of northwest (NW) and southeast (SE).

These current patterns are crucial considerations for various activities in the Yadana area, such as offshore operations, navigation, and environmental monitoring.

 


Temperature:
Sea water temperature in the Yadana area exhibits seasonal variation, with lower temperatures typically observed from December to February and higher temperatures in May. Maximum water temperatures, around 30°C, occur during transition seasons between monsoons when there is less mixing. The average sea surface temperature ranges between 26°C to 30°C throughout the year.
The temperature variation with depth reveals three distinct water masses:
•	From the surface to 17 meters depth, the sea water temperature remains relatively stable at 28°C.
•	Between 17 to 22 meters depth, the sea water temperature increases from 28°C to 29°C.
•	From 22 to 40 meters depth, the sea water temperature decreases from 29°C to 25°C.


Gas Composition Notes:
•	Reservoir fluid assumed saturated with water.
•	CO2 content: 3.8% mol, H2S content: Actual 20 ppm, Design 50 ppm.
•	Initially, Yadana gas assumed as pure dry gas with GCV above 715 BTU/SCF.
•	After Start-Up (SU), CO2 found to be ~4% and N2 ~25%, resulting in Yadana sales gas GCV around 711.5 BTU/SCF.
•	TEPM installed C6 injection facilities at PLC to increase sale gas GCV to 720 BTU/SCF; Hexane injection prepared but not used.
•	C6 injection facilities decommissioned in August 1999 at PTT's request, accepting Yadana Sale Gas GCV at 711.5 BTU/SCF level until WP-3 development.
•	Yadana gas contains ppm of C20+ causing side-effects like high-density liquid condensate recovery inside TEG loop on PP and retro-grade condensation along export pipelines.
•	C20+ evaluated through on-site measurements via C6+ campaign using prototype lab equipment in August 2001.
•	WP3 production (Sein reservoir) started in 2006, Sein gas contains more C6+ than Yadana gas, leading to contractual liquid issue with PTT in 2007.
•	Liquid issue settled in 2009 by limiting Yadana export gas GCV at around 720 BTU/SCF.
•	Limit later removed as gas blended with other productions (PTTEPI - Zawtika & PCML - Yetagun).
•	Badamyar gas has lower N2 content, sampled gas from exploration phase shows little or no H2S and traces of CO2 (0.05%mol).
•	Badamyar gas considered to contain fewer heavy end components than Yadana and Sein, with no presence of C4+.


Water Management Notes:
•	Yadana, Sein, and Badamyar gas reservoirs are water saturated, and produced water mainly results from water condensation.
•	Design limit of 900 BWPD allocated to WP-3 wells, and 500 BWPD for each wellhead platform WP-1 and WP-2.
•	WP4 maximum reservoir water production is 900 BWPD (end of life 2024-2025).
•	Produced water treatment system initially designed for 1200 BWPD in 2008/2009, Total HQ recommended against extending the water treatment facility.
•	Current philosophy is to cut back production from Yadana and Sein once reservoir water is produced.
•	Surface facilities can handle a total of 1900 BWPD.
•	Produced liquid, mainly composed of produced water, condensate, and glycol, injected into Badamyar R5 aquifer via disposal well YAD-1A.
•	YAD-1A maximum acceptable liquid flow rate: 60 m3/day (~380 bbl/day) with maximum allowable wellhead injection pressure.
•	YAD-1F (water breakthrough well) potentially selected to convert into a new injector well in early 2021 if liquid production capacity increases.
•	Current liquid injection pumps designed capacity: 9.0 m3/h, working flow rate: 8.0 m3/h (1200 bbl/d), exceeds YAD-1A limit.
•	Injection of biocide recommended before liquid injection into Yadana reservoir to control H2S level, maintain gas sales specifications, and prevent microbial-induced corrosion (MIC).
•	Addition of dedicated injection skid proposed to control volume and concentration of biocide injected into reservoir, reduce risk of oxygen containment, and limit manual handling for personnel safety.


2.3. Badamyar Sand Management:
•	Badamyar reservoir consists of unconsolidated sandstone prone to sand production.
•	"No Sand Production" strategy employed, with sand-producing wells choked back until sand production stops.
•	Completion with Open Hole Gravel Pack (OHGP) used for sand control in all wells, providing good protection if set correctly and maintained.
•	Sand management strategy includes:
•	Designing WP4 and production sea line to sustain sand erosion.
•	Specific ramp-up procedures for Badamyar wells to preserve completion efficiency.
•	Surface monitoring for sand production, with sand-producing wells choked if detected.
•	Sand recovery facility installed on PP platform downstream of existing free water flash drum.
•	Provision for a de-sanding unit on WP4 for future treatment of sand-producing wells.
•	Acoustic Sand Detectors (ASD) and erosion probes installed on all flow lines for monitoring, with lower detection limit around 1 kg/d.
•	Pigging operations conducted monthly for the first 6 months after Badamyar production start-up to verify equipment functioning and "no sand" philosophy.
•	Monthly pigging frequency reinstated for 3 months for cleaning and verifying no excessive solids production.
•	MP FWKOD controlled yearly after Badamyar production start-up to confirm sand accumulation rate.
•	Significant sand accumulation in MP FWKOD may result in compressor shutdown for removal and high penalties for gas supply outages.


 


3.	Quarter Platform:
  
3.1 General Overview
•	The quarter's platform serves as accommodation for staff, housing various facilities including the main central control room, maintenance workshop, warehouse, and utilities.
•	Designed to accommodate 114 persons in normal operation, with a maximum capacity of 135 persons.
•	Layout includes:
•	Offices on the first deck.
•	Kitchen, dining room, and recreation rooms on the second floor.
•	Cabins for personnel on the third floor and intermediate deck.
•	Main helideck on the roof deck.
•	Utilities housed on the cellar deck and intermediate deck include:
•	2 main fire pumps, 2 jockey pumps, and 2 sea water lift pumps.
•	Potable water maker and treatment facilities.
•	Potable water tanks.
•	Sewage treatment unit.
•	Electro chlorination package  (Electro chlorination is the process of producing hypochlorite by passing electric current through salt water. This disinfects the water and makes it safe for human use, such as for drinking water or swimming pools.)
•	Emergency generator, battery room, transformers.
•	Diesel day tanks for emergency generator and fire pumps.
•	Sump tank for collecting machinery drains.
•	Jet-fuel drip pans drains directed to the sea.
•	Garbage compactor.

3.2. Control Room
The Control Room is the nerve center of the offshore operation, responsible for overseeing and managing various aspects of process control, safety systems, and communication. Here's an overview of its functions and equipment:
Functions:
1.	Operation and Control: Manages the process and utilities of all platforms.
2.	Safety Management: Gathers information and actions related to safety, including Fire & Gas (F&G) and Emergency Shutdown (ESD) systems.
3.	Data Transfer: Transfers minimum data between offshore and onshore facilities.

Operator Interfaces:
1.	PCS / PSS Operator Stations: Allows operation of process and utilities units, ESD system, and F&G detection systems.
2.	ESD Panel: Hardwired hand switches for emergency shutdown.
3.	Fire Water Pumps Panel: Controls fire water pumps.
4.	Fire and Gas Matrix Panel: Backup deluge hand switches for fire and gas systems.
5.	Inhibit/Isolate Permissive Key Switch Panel: Provides permissive I/O overrides.
6.	Telecommunication Equipment: Includes CCTV control, Public Address/General Alarm Console, UHF and Marine VHF remote units, telephone sets, Meteo display Unit, RSI Simulator, and Wave meter data.
7.	CCTV Monitors: Displays CCTV feeds for wellheads and flare.
8.	VDU for Power Distribution Control (PDC) System: Monitors and displays power generation and distribution data.
9.	Computer and Printer: Used for various administrative tasks such as work permits, filing procedures, production reports, and personnel planning.
10.	Intouch Console: For PSS inhibition.

   
Remote Control and S/D Functions:
1.	ESD2: Closure of well wing & master valves and sea-line ESDV.
2.	ESD1: Closure of well DHSV's and ESD2, and utilities shutdown.
3.	Individual Well Control: Closure and reopening of individual wells, choke adjustment, and test separator control.
4.	ESD3: Test separator control and emergency shutdown.
  
Information Available in the Control Room:
1.	Wellhead Platforms (WP1/WP2):
•	Communication status
•	Video camera watch (WP2 only)
•	Hydraulic system pressure, level, and pump status
•	Wellhead pressure, temperature, and flow values
•	Sea-line pressure & temperature (WP2 only)
•	Well test meter flow, pressure & temperature
•	Well valve status
•	Platform ESD status
•	Fire & gas detection system status
•	Corrosion inhibitor tank level and pumps status
•	Closed drain drum level
•	Pigging status
•	Platform electrical common alarms

2.	WP3:
•	Communication status
•	Hydraulic system pressure, level, and pump status
•	Well valve status
•	Wellhead pressure, temperature, and flow values
•	Sea-line pressure and temperature values
•	Corrosion inhibitor tank level, injection pressure, and pump status
•	Platform ESD status
•	Platform F&G detection
•	Pigging status
•	Navaid status
•	Platform electrical common alarms

3.	WP4:
•	Communication status
•	Hydraulic system pressure, level, and pump status
•	Well valve status
•	Wellhead pressure, temperature, and flow values
•	Corrosion inhibitor tank level and pump status
•	Platform ESD status
•	Platform F&G detection
•	Pigging status
•	Platform electrical common alarms

3.3. Utilities - Instrument Air:
•	System Description:
•	Self-contained system for producing dry instrument air with 5°C dew point at 8 barg.
•	Components include:
•	Air compressor rated for 75 Nm3/h with air cooling.
•	Drier package with two columns (one in operation and one in regeneration).
•	QP2 air receiver sized to provide 15 minutes of autonomy on QP2 air consumption if pressure falls from 7.0 barg to 4.0 barg.
•	Operation during Normal Conditions:
•	QP2 air system not expected to be required during normal operation.
•	Control logic panel independent of central PCS (Process Control System) but linked to it.
•	Air compressor operates on a load/unload basis between pressure levels of 7.4 barg and 5.5 barg.
•	Machine starts at 5.0 barg and stops at a predetermined time delay after unload.
•	Backup Functionality:
•	QP2 air can serve as a backup to the PP/MCP air system.
•	Unload/load levels differ from PP/MCP units.
•	User Priorities and Regulation:
•	Instrument air to QP2 users, particularly HVAC actuated valves, is the preferential user.
•	Self-regulated PCV maintains 6.5 barg downstream on the instrument air distribution system.
•	Service air has a self-regulated PCV to maintain 5.5 barg upstream of the valve.
•	Maintenance and Testing:
•	QP2 air compressor test run scheduled for 6 hours per week.
	

Utilities - Fresh Water / Potable Water System:
•	Desalination Process:
•	Fresh water maker package with 2 reverse osmosis trains installed on QP2.
•	Sea water supplied by jockey pumps, chlorinated, filtered, then passed to the desalination unit.
•	Capacity and Treatment:
•	Designed capacity of 42 m3/day.
•	Produced water filtered (granulated active carbon), sterilized, re-mineralized, and chlorinated.
•	Chlorine solution injected separately from electro chlorination package.
•	Storage and Distribution:
•	Fresh water stored in tanks on QP2 with total capacity of 234m3.
•	Tanks designed to supply fresh water requirements for 7 days if fresh water maker is out of order.
•	Water pumped from tanks by 2X100% centrifugal pumps.
•	Distributed to service water network (QP2, PP, MCP) and potable water users (kitchen, laundry, showers).
•	Usage Guidelines:
•	Potable water used as service water for central complex limited to necessity only.
•	Sea water from fire water network used for major cleaning/wash-down operations.
•	Hot Water System:
•	Fed with potable water and distributed by 2 x 100% pumps.
•	Pumps rated at 6.5m3/h at 3.54bar differential per pump.
•	Distribution:
•	Potable water distributed to:
•	QP2 for kitchen, cabin usage, laundry, and sanitary usage.
•	PP/MCP/LCP for utility stations.


Utilities - Sewage System:
•	Grey Water Treatment:
•	Grey water from the kitchen undergoes initial treatment by passing through a starch and grease separator.
•	It is then mixed with other grey and black waters for further treatment.
•	Sewage Treatment Package:
•	Consists of:
•	Initial collection tank.
•	Three stages:
•	Treatment tank (T-4932) equipped with blowers.
•	Post-filtration (T-4933).
•	Discharge tanks (T-4934) equipped with pumps.
•	Additional Treatment Equipment:
•	Ionizers and UV reactors are provided for:
•	Anti-fouling.
•	Disinfection.
•	Sterilization of treated water.
•	Disposal Method:
•	Treated water is disposed of overboard via a dedicated caisson.


Utilities - Drainage System:
•	Collection:
•	Open oily drains from fire water pumps and emergency generator packages.
•	Overflow from fresh water tanks.
•	Collection Point:
•	Collected to an open drain sump drum (D-4430).
•	Ventilation:
•	The sump drum is vented to the atmosphere.
•	Overflow Handling:
•	Overflow from the drum (water with less than 40mg/l oil) flows by gravity via a liquid seal loop overboard.
•	Hydrocarbon Recovery:
•	Recovered hydrocarbon can be evacuated by connection of a portable pump.

Utilities - Fire Water System:
•	Design:
•	Combined ring main system serving QP2.
•	Supplied with sea water by three 50% pumps.
•	Two pumps located on QP2, one on PP.
•	Pump Types:
•	QP2's fire water pumps: Submerged electrical pumps fed by a dedicated diesel generator.
•	PP's fire water pump: Diesel-driven submerged pump.
•	Pump Capacity:
•	Each fire pump has a capacity of 750 m3/h.
•	Diesel Day Tanks:
•	Each fire pump has its own 12-hour diesel day tank fuel supply.
•	Jockey Pumps:
•	Two jockey pumps installed on QP2:
•	One operating and one spare.
•	Nominal capacity of 50m3/h each.
•	Electric motor driven.

Utilities - Electro chlorination System:
•	Purpose:
•	Produces 500ppm chlorine solution.
•	Usage:
•	Dosage to various systems:
•	Sewage effluent (only during maintenance of the sewage package).
•	Sea water lift pumps.
•	Jockey pumps caisson.
•	Fire water pumps caissons (QP2 and PP).

Utilities - Electrical Power Supply:
•	Emergency Generator:
•	Installed capacity: 1000 kW.
•	Serves essential users on QP2, PP, and WP1.
•	Dedicated EDGs for LCP and MCP.
•	Emergency Power Supply Users:
•	Vital lighting.
•	Safety systems (ESD, F&G, PA).
•	Telecommunication systems.
•	UPS.
•	HVAC.
•	Jockey pumps.
•	QP2 crane.
•	Kitchen and laundry.
•	Fresh water supply.
•	Diesel distribution.
•	Operation:
•	Automatically activates upon main power supply failure.
•	Independent starting arrangement.
•	Can be synchronized with main generators.
•	Fuel Supply:
•	Day tank has sufficient fuel for 24 hours of 'full-load' operation.
•	Auto start not functional for ESD 0 level on QP2/PP for safety reasons.

Utilities - Diesel
-	A 2" line is installed on bridge to import diesel from PP for supply to fire water pumps and emergency power generator.