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Brownfield Modification Project for Onshore Depletion Compression at Musandam Gas Plant (MGP)

Project Summary

Elixir Engineering  was awarded to perform to ensure safety and optimise production with comprehensive Onshore Depletion and Compression Enhancements at the Musandam Gas Plant (MGP)

The Bukha Alpha platform is located roughly 23 kilometers from the Musandam Gas Plant (MGP), and the Bukha Field is located in Block 8 about 23 km offshore from the western coast of the Musandam Peninsula. The Bukha and West Bukha oilfield are located in Offshore Block 8, which produced 4,458 barrels of oil equivalent per day on average in 2018. As of January 2019, MOGC (Musandam Oil and Gas Company), which is wholly owned by MOGC (OQ E&P LLC), is in charge of operating Block 8.

The Musandam Gas Plant ("MGP"), an onshore processing plant, handles all of the production from Block 8. Whereas downstream gas processing units need an optimum operating pressure. The MGP's inlet arrival operating pressure is in optimum condition. The three inlet compressors located downstream of the slug-catcher are utilized to increase the pressure to the required pressure. It is necessary to maintain the compressor setup such that one compressor is kept in standby mode.

Presently, in order to achieve the required inlet pressure at MGP, the wells at Bukha and West Bukha are being operated at nominal pressure. Production wells are in depletion mode, generating primarily gas and a lesser amount of water and condensate. It is suggested that the MGP plant intake be operated at a lower pressure rate in order to improve production there. As part of the conceptual study, various configurations of inlet gas compressor arrangements were examined in order to support the aforementioned proposal, and option 3A configuration was determined to be a workable choice.
In order to combine the project scope with the current plant for the reduced operating pressure at the slug

Production wells are in depletion mode, generating primarily gas and a lesser amount of water and condensate. It is suggested that the MGP plant intake be operated at a lower pressure rate in order to improve production there. As part of the conceptual study, various configurations of inlet gas compressor arrangements were examined in order to support the aforementioned proposal, and option 3A configuration was determined to be a workable choice. In order to combine the project scope with the current plant for the reduced operating pressure at the slug catcher inlet, the following change will be necessary.

After the particle filter/coalescer, new piping must be tied in downstream to route the gas to the new LP compressor suction via an LP suction scrubber. In order to meet the current gas compressor inlet parameters, gas pressure must be increased at the LP compressor inlet. To fulfill the project's requirements, the current inlet gas compressor arrangement must be modified to (1W+2S). In accordance with current circumstances, gas pressure has been increased to satisfy the GSU battery limit requirement.

After the slug catcher condensate common line, a new tie-in must be created to integrate the new condensate booster pump. Condensate operating pressure has been raised to match the existing operating pressure at downstream. Produced water from the slug catcher is re-routed to the existing skim system instead of connecting downstream due to the low operating pressure of slug catcher.

A new tie-in shall be made to provide fuel gas blanketing for MP production separator with the required operating pressure due to limitation of fuel gas supply pressure at downstream & constant supply to the pre-flash vessel in order to keep the necessary operational pressure.

The EPC scope of work includes the Engineering, Procurement, Manufacture, Fabrication, Logistics, Supply, Construction, Installation, Erection, Managing Interfaces, Interconnection, Supervision, Training< Pre-commissioning, Commissioning, Start-up, Testing and completion of the facilities; performing warranty and remedial work concerning the facilities, the provision of spares, and the provision of As built, Asset registration all document required for final acceptance of the work and project hand over including arrangement of temporary facilities.

The following actions are part of the work, but they are not the only ones:

  • FEED verification and to provide the FEED verification confirmation that FEED is accepted, during the bidding stage
  • Data collection, site survey, further develop the FEED deliverables during Detailed Design and detailed design from FEED package including all required design, safety studies, and reviews
  • All materials procurement including long lead items
  • Construction, and equipment installation as per AFC drawings
  • Pre-Commissioning, Commissioning, Start-Up, performance test
  • Submission of all Redline markup and As-built drawings / Documents, SAP/asset registration, and all documentation required for final acceptance of the work and project handover.
  • Temporary facilities (offices, Accommodation, Camp Facilities, Laydown Area, Workshop, Storage yard, and reinstate post project completion).
  • Compliance, Implementation and obtain necessary approvals for any of Government authorities, regulations and requirements.
  • Compliance and Implementation of all COMPANY HSSE, QA/QC policies, procedures, guidelines, technical Specifications, and standards

Following major equipment/modification anticipated:

  • 1W+1S – New LP stage compressor package with associated packages and accessories
  • Modification / tie-in with existing compressors
  • LP Compressor after cooler per LP compressor
  • Condensate Booster Pumps
  • LP Inlet Scrubbers
  • Control and ESD valves
  • Control system Upgradation
  • Adequacy verification of existing facilities
  • Fire water network with fire fighting equipment
  • Utilities extension
  • Early tie-in, Hot tap tie-ins, Electrical & utility tie-ins
  • Installation new equipment piping , electrical, instruments, tele-communication, CCTV, civil supports, earth works, fence, HVAC(if required), Electrical, and instrumentations as per approved construction documents.
  • The scope also includes modification of existing facilities and reinstate the existing facility.

In context to the above scope of work, Elixir Engineering has done below listed safety studies for the Brownfield modification project for Onshore Depletion- Compression at MGP.

Safety Studies
  • EERA
  • F&G Mapping
  • FERA
  • PEM
Escape, Evacuation and Rescue Analysis (EERA)
Escape, Evacuation & Mustering Process:

Escape, Evacuation & Mustering Process
Escape, Evacuation & Mustering Functional Requirements

The Escape, Evacuation, Mustering and Rescue facilities include the following

  1. Alarm and Communication system
  2. Escape Routes
  3. Muster Area / Assembly point
  4. Rescue facilities
  5. Emergency Training

Escape, Evacuation & Mustering Study Methodology

The EER approach recognises that there are many potential Major Accident Hazard scenarios, which may require EER. The Major Accident Hazard scenarios will be assessed for their potential to impair the escape, evacuation and rescue systems. The study involves an assessment of EER systems with regards to the egress, escape, evacuation and rescue goals and impairment criteria. A review of each process area will be undertaken to determine whether the escape routes and muster locations can be impaired under impact from MAHs. The purpose of this review is to determine whether the provided EER facilities are adequate or any additional EER systems are required.

Time required to escape and muster to the Muster areas will be estimated in this study. The estimated time will be used to determine the minimum criterion for which the Muster areas are required to maintain their integrity (endurance time). The EER arrangement availability and effectiveness will be assessed under the various MAH scenarios.

The following Methodology will be followed for the EERA study

  1. MAH Scenario Identification: Identify the MAH scenarios, using the FERA study;
  2. EER Goals: Identify the EER goals, for which the EER facilities will be assessed against;
  3. EER Criteria: Indicate the EER criteria to be used to assess whether the EER goals are met;
  4. EER Facilities: Describe the EER facilities at MGP;
  5. Detection and Alarm Review: A review of the effectiveness of the Detection and Alarm system for this project in providing adequate warning of an impending MAH scenario will be made. Estimation of time to alarm and its audibility to onsite personnel, make work safe, escape and muster will be provided;
  6. EER Impairment Assessment: Assess the impairment of the EER facilities against the EER Criteria, in order to check whether the EER Goals are met;
  7. If EER Goals are not met, adequate recommendations are provided;

MAH Scenario Identification

The development of Major Accidents from consideration of the Major Accident Hazards (MAHs) present at the facility must be clearly identified.

Fire and Gas Mapping Study (F&G)

The objective of F&G Mapping study is to ensure F&G detectors are distributed in line with the F&G philosophy of project based on Fire & Gas Detector Layout, Identify any gaps and to make recommendations where required on the number and placement of various detectors.

Fire & Gas detection

Prompt detection of gas release or a fire at its earliest stage of development is a crucial factor for a fire protection system to be effective, with a rapid response minimizing the potential for the event to escalate. A good fire & gas detection system gives detection provisions aligned with the hazards presented across the facility, providing a response that minimizes the impact of releases to personnel, assets, and the environment. Detection can take place by personnel or by safeguarding instruments, with instrument detection systems that includes the following:

  • The ability to detect gas leakage through gas detection
  • Fire detection, which provides a warning to flame/heat generated by a fire (e.g. flame detection, /heat detection).

The nature of the response is typically defined in the facility’s Fire & Gas philosophy, that depends on the risks associated with the facility, the detection systems can be used to either provide an alarm requiring personnel action and/or to initiate executive actions, such as plant isolation automatically.

Methodology:

Step 1: Hazardous Area Identification - The Musandam Gas Plant (MGP) will be critically assessed for identifying all hazard (fire and gas (flammable & toxic) hazards) areas that are present will be segregated into different hazardous detection areas /Mapping areas.

Step 2: Hazardous Area Characterisation - From the above identification, major accident hazards will be characterized based on the likelihood and frequency of the incident related to the properties of the fluid and quantity of the fluid released.

Step 3: Risk Volume Definition - The Risk Volume will be defined for the identified hazardous area in line with company/International standards/Good Engineering Practices.

Step 4: Identifying the distinctive cloud for detection - The Risk Volume will be assessed and the cloud size for detection will be identified in line with company/International standards.

Step 5: Detect 3D Modelling - The 3D Geometry file will be imported to the software and the Fire and Gas detectors will be placed based on preliminary F&G Layout at the hazardous zone.

Step 6: Coverage Mapping - The newly installed detectors in the layout will be evaluated in accordance with the performance target to determine whether or not they are positioned appropriately to sense and identify any potential fires and gas dispersion at that site.

Step 7: Optimization/Detector Layout Definition - For each loss of containment scenario, use the same procedures as above. If the detectors are discovered to be insufficient to sense or detect the dispersion, adjust the height of the detector or move its placement to better align with the hydrocarbon release's dispersion coverage.

F&G 3D mapping study methodology
Fire and Explosion Risk Analysis (FERA)

The key objectives of FERA study are as follows:

  • Identify the potential Fire and Explosion Hazard Sources;
  • Evaluate the potential fire;
  • Escalation to adjacent Fire Zones;
  • Active fire protection requirements;
  • Evaluate the potential Explosion Overpressure Impact on Critical Structure, Plant Buildings etc;
  • Passive Fire protection requirements;
  • Evaluate the toxic Gas Impact to the plant personnel;
  • Assess the plant building blast resilience requirements.
  • Location for Manual activate provision of Deluge system
  • Evaluate the impact from existing unit to other units.

Methodology

A systematic and organized method for determining and evaluating the risks associated with fire and explosion threats is called Fire and Explosion Risk Assessment, or FERA. To guarantee safe facility layouts, the assessment's findings are used as inputs to fire zone assessment, specify active and passive fire protection system requirements assessment, and provide inputs for escape, Evacuation and Rescue Assessment (EERA), Occupied Building Risk Assessment (OBRA), and Quantitative Risk Assessment (QRA) studies. FERA will assess the fire and explosion scenarios for Brownfield Modification Project for Onshore Depletion Compression at Musandam Gas Plant (MGP).

For the Brownfield Modification at MGP, the FERA shall involve the following major steps

  1. Development of FERA study assumptions.
  2. Identification of fire, explosion and flammable hazards i.e. jet fire, pool fire, flammable gas dispersion, BLEVE, VCE etc.
  3. Estimate hazard inventories based on isolatable sections, i.e. isolation valve to isolation valve (for normal operating conditions).
  4. Determination of failure probabilities based on the parts count method for each of the identified failure cases.
  5. Define locations and facilities for control and mitigation, i.e. isolation of systems using P&IDs, PFDs, Plot Plans and other relevant details, including all major equipment items.
  6. Identify Potential Explosion Sites (PES) based on the review of the plot plans, 3D models, PFDs, site visits that have the potential for gas accumulation, congestion and confinement within the plant/facilities and nearby areas. For each of the PES determine the blast potential.
  7. Identify receptors to be evaluated as a part of FERA study, such as critical structures, buildings etc.
  8. Using the predefined release size, consequence modelling will be performed using COMPANY approved software package for the identified fire, and explosion hazards
  9. Determine event probabilities for each of the failure cases (i.e. directional probabilities, wind profile, failure probabilities, ignition probabilities etc.)
  10. Review the impact of fire and explosion events on the facility, and in particular:
    • Assess the escalation potential;
    • Assess the impact on occupied buildings/ and buildings containing critical equipment;
    • Assess the impact on HSE critical equipment and systems, key structures, EER measures and supporting structures;
    • Review the existing protection measures in place based on the above review and identify recommendations, if any, to reduce the impact from fire and explosion.
  11. For each of the identified receptors, based on the event probabilities, fire and explosion assessment, determine the exceedance curve and contours based on the impairment frequency and vulnerability criteria.
  12. Carryout fire zone assessment to determine fire zone for new plant area.
  13. Review of active and passive fire protection based on the defined fire zone.
  14. Providing Conclusion and recommendations
FERA methodology
Physical Effect Modelling (PEM)

The key objectives of PEM study are as follows

  • Identify The Potential Fire and Explosion Hazard Sources;
  • Evaluate the Potential Fire;
  • Escalation to Adjacent Fire Zones;
  • Evaluate the Potential Explosion Over pressure Impact on Critical Structure, Plant Buildings etc;
  • Evaluate The Toxic Gas Impact to The Plant Personnel;
  • Assess the Plant Building Blast Resilience Requirements.
  • Evaluate the impact on Muster points.

Methodology

Physical effect modelling (PEM) is a structured and systematic process to identify and assess the impacts from fire and explosion hazards. The evaluation's findings are applied to guarantee secure facility designs.

  1. Hazard identification: Most hazardous events involve loss of containment from process equipment. Potential hazardous outcomes. For identifying hazardous inventories, the assessment was done considering pressure, temperature and composition reported from the respective equipment.
  2. Consequence analysis: The consequence modelling for loss of containment was done using Pressure vessel modelling software. The same model can be used to determine the flammable & toxic dispersion and thermal radiation.
  3. Layout Spacing: The minimum separation distance to prevent escalation between equipment is based on the distance to the 37.5 kW/m2 contour from jet fire arising from a 22 mm hole size and LFL flammable gas concentration between equipment handling hydrocarbon and ignition source. The required fence distance was also analysed based on the toxic and thermal radiation criteria.
  4. Review the impact of fire and explosion events subjective to the facility
  5. Providing Conclusion and recommendations

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