Agbada NAG

As part of the Nigerian government’s initiative to increase its output of domestic gas supply, key proven gas wells and Crude oil processing installation in SPDC (Shell Petroleum and Development Company of Nigeria) eastern and western production areas were chosen for this natural gas gathering project. To this end, Makon Engineering and Technical Services (METS) was awarded the contract to build Gas Holding Facilities (GHF), to process Domestic Gas (DomGas), from these project locations. Agbada area is one of these locations.

The scope of work to be done for Agbada gas gathering project shall include:

  1. Drill 2 NAG wells and hook-up (By Others)
  2. Lay 2 No. 8” x 8km NAG flow line from wells at Agbada-1 to NAG plant at Agbada-2.(By Others)
  3. Pig launcher and receiver installation on the flow lines. (By Others)
  4. Install 2 by 40 MMscf/d NAG processing train (METS)
  5. Installation Sliding Vane Compressor at Agbada 2 flow station to reduce gas flaring.

The Agbada NAG project is an EPIC + 3 years O & M (Engineering, Procurement, Installation and Commission, with 3 years Operation and Maintenance) in its scope as awarded to METS. As part of the gas gathering project, it is located in the northern region of River state in Nigeria, and located about 20KM from Port Harcourt. At present, the Agbada fields; located at OML 17 area (belonging to SPDC) for crude oil exploration, consist of Agbada 1 and Agbada 2 flow stations. These flow stations are connected to several pipelines from existing wells within the area.

The Agbada 2 flow station area, in addition to crude oil processing facility, consist of AGG (Associate Gas Gathering) plant for gas compression, with a Tie-in from Agbada flow station 1; this is the location for the Agbada NAG/AG project (See figure 2). The project involves installation of 2 X 40mmscf/d trains GHF (gas holding facility) to process natural gas for local consumption. The scope of the GHF includes:

  • Tie-in to pig receiver from pipeline connecting 2 gas reservoir
  • Installation of 2 Trains of gas processing facility
  • Outlet of GHF to connect to existing gas export pipeline in the Eastern domestic gas network (EDG), which terminates at NGC (Nigeria Gas Company) gas manifold at Obigbo in Rivers state of Nigeria.

The associate gas during crude oil processing at the Agbada 2 flow is still being flared; in other to reduce flaring of gas and increase the output of gas supply, the AG part of the project comprises of:

  1. Installation of screw booster compressor system to gather gas from the surge vessel operating at 0.2 BarG at Agbada 2 flow station.
  2. The boosted gas will be tied into the inlet header of the LP compressor at 4.5 BarG in the Agbada AGG plant
  3. The capacity of surge vessel gas compressor is 0.8 MMscfd.

The objectives of Agbada NAG project includes the following:

Standardized design template and equipment packages that can be modularized and be adapted for other locations.

  •  The need for operational integrity throughout the projected 25 years life cycle of the facilities.
  • The need for safety and security of personnel and plant with due regard to protection of the internal working and external environments.
  • The requirement for high availability, reliability and low total cost of ownership, over the life span of the facility.
  • The needs, concerns and aspirations of host communities.
  • Minimization of site work to reduce exposure of personnel and equipment.
  • Minimization of adverse social/environmental impact.
  • Designs to allow parts of the project to be fabricated and/or constructed as much as possible in Nigeria by Nigerian companies.
  • Minimum loss of production during project implementation by off-site pre-fabrication and pre-commissioning of equipment packages.
  • Optimum use of existing utilities and infrastructure.
  • Flexibility with respect to future development scenarios.

The engineering design process is subdivided into FEED (Front End Engineering Design) and DED (Detailed Engineering Design); see below. This involves design in various areas of engineering involved in the GHF; Civil, Electrical, Process, Instrumentation, Telecoms, following SPDC’s DEP and International standards where applicable. The design process was executed by METS engineering department in conjunction with Enerflex Limited of Canada; who is the major equipment manufacturer for the project. Other inputs were from Siemens (instrumentation and electrical) and ODS systems (metering package)

The Agbada NAG/AG project will feature the following packages:

  • Processing Packages
  • Inlet manifold skid
  • Inlet facility
  • Hydrocarbon Dew Point Control
  • Refrigeration System
  • Glycol Injection and Regeneration system
  • Condensate Flash Stabilization
  • Off Gas Compression System – This is common for both train
  • Metering Skid
  • Utility Packages
  • Flare System
  • Fire and Gas system
  • Field Ancillary Room (FAR)
  • Main Control Centre (MCC)
  • Instrument Air
  • Closed and Open Drain Systems
  • Power Generation
  • Service water
  • Fire Water

Front End Engineering Design (FEED)
Agbada NAG/AG FEED was carried out by Enerflex Limited of Canada with METS, while SPDC reviewed and approved all designs/documents. The FEED for Agbada NAG/AG has been completed, with necessary HAZOP (Hazard and Operability Studies) carried out.

Detailed Engineering Design (DED)
The DED involves PEFS (Process Flow Schemes), GA (General Arrangement) drawing, civil design calculations, civil structural drawings, civil design calculations mechanical and piping drawings, electrical design drawings, instrumentation design/layout and general equipment layout. Enerflex limited Canada, being METS major equipment manufacture played a major role for Agbada NAG/AG DED.

At present, Agbada NAG DED has progressed to 70% and Agbada NAG DED is at 65% respectively. . Bulk MTO (Material Take-Off) for Piping and steel structures, civil foundations/structure, and electrical materials have been generated.

The scope for procurement as derived from FEED is subdivided into Foreign Long Lead Item, Overseas Bulk items and Local procurements.
Foreign long lead items procurement is as listed below:
Most of the GHF process equipments were procured from Enerflex Limited of Canada. These includes; reciprocating overhead and Sliding Vane compressors, fuel gas packages, Inlet Knockout Separators, HCDP units, glycol injection and regeneration package, inlet facility unit, electrical control panels, inlet classifier units, off gas compression package and refrigeration package.

Siemens of Germany designed and assembled the Low voltage switchgear.
MPS (Makon Power Systems) in conjunction with Siemens are to supply 2# Caterpillar gas driven generators and 1# diesel driven generator.

Overseas Bulk Materials
DTS (Dexcrest Technical Services Ltd of United Kingdom) were contracted to provide various overseas bulk materials such as pipes and fittings, gantry crane and accessories, electrical cable glands, distribution boards, Instrument junction boxes and instrument Tubing and fittings, Uninterrupted power Supply and accessories, etc.

Local Procurement
This consist basically construction and fabrication consumables, roofing materials, electrical cables, etc, to be procured/fabricated locally in Nigeria, this is as described below:

  • The smokeless Flare Ignition Panel and flare structure is to be fabricated locally by BOSKEL. This will be made up of two distinct flare stack, for LP (low pressure) and HP (High pressure) respectively.
  • AOS Orwell will be responsible for Process Automation System (PAS) and Safety Instrumented System (SIS). The PAS and SIS constitutes the Integrated Control and Safety System (ICSS) which provides centralized monitoring and supervisory control via human/machine interface which serve as the operator’s single window to the entire plant.
  • Supply of civil construction material by host community contractors.

Agbada NAG is a green field, and METS will be responsible for all construction activities. At present piling for compressor foundations have already commenced, and the piling works is being done by Dorig Nigeria Limited (a Nigerian company).

Construction works shall include:

  • Steel fabrications and installations of sheds,
  • Concrete works for process equipment foundations and other heavy equipment like generators’ foundations.
  • Lifting and placing of packages on foundations.
  • Construction of walkways, pavements and drainage
  • Survey and probing of construction area
  • Electrical equipment installations
  • Pipe rack foundation and piping
  • Cable tray installation
  • Cable installation and termination
  • Tie-ins to points on pipes and vessels in Agbada 2 flow station
  • Instrumentation, automation and control equipment installations
  • Piling/ Excavation/ Blinding/ Re-Barring/ Formworks.
  • Concreting/ Concrete casting.

This involves pre-start up of all individual long lead equipments; reciprocating and sliding Vane compressors, fuel gas packages, Inlet Knockout Separators and Instrument air package, process equipments, power systems (low voltage switchgear , gas and diesel generators), etc, for test run, to ensure all systems are adequately installed and operates as rated.

This is followed by final integration into a single system, which is run as a whole unit, to ensure that GHF operates as designed. To ensure a seamless and successful commissioning, detailed commissioning processes are to be duly adhered to during this phase.

The scope of Agbada NAG/AG is robust, rather than a 90 day reliability test, the project will involve post commissioning 3 years operation and maintenance; which will be performed by METS as stipulated in its contract with SPDC

In order to keep a complete and meticulous track of all documents associated with the project, METS has a department which acts as a document control centre (DCC) which handles transfer, storage and archiving of all documents.

These documents, as prescribed by SPDC will have unique numbers for identification, and will be handed over to SPDC at the end of the contract duration. During the duration of the contract, transmittal of documents between SPDC, Enerflex and METS is by FTP.
METS uses Egnyte for storage of documents and link for receiving/transmittal of documents.

After the completion of the project, the facility will be maintained and operated by METS for duration of 3 years, before it is handed over to SPDC. This involves:
• Provision of spares for servicing and overhaul of equipments and infrastructure.
• Provision of maintenance personnel; mechanical, electrical and instrumentation, and operational staff
• Provision of reliable CMMS (Computer Maintenance and Monitoring system) for scheduling and tracking of maintenance activities.
• Provision of fully functional office; including maintenance workshop and adequate office accommodation.
• Liaising with SPDC maintenance team during the duration on shut-downs and maintenance activities, in other to be in seamless operation with other SPDC facility that the plant is connected to.