A Day in the Office

Yesterday I have been working the whole day helping the other Field Engineers to prepare the tender for Sabah Oil and Gas Terminal (SOGT) Transportation and Services Project. I have been given the chance to actually get my hands on preparing the Pipe Line End Manifold (PLEM) installation procedure. I have been stayed back in the office to finish the work up and right now I am still in the office doing the same work. Guess the tender job is really a hectic job and I always wonder why people complaint if they were assigned to do the tendering job. But it was a good experience anyway.

The PLEM will be installed once the pipeline has been laid onto the seabed and the pipeline end will be connected to the PLEM that will be in connection with the Single Point Mooring (SPM). An SPM will be the main connection point for any Oil Tanker to load or offload the products from the ship to the facility or from the facility to the ship before the products will be transported to other refinery plant or storage plant.

Swissco Shore Inspection

Figure 1.0: Crane at lock position

Figure 1.1: Lifting of Crane Boom

Figure 1.2 Unextended Boom (length 6.5m)

Figure 1.3: Extended Boom (length 8.5m)

Figure 1.4: Safe Working of the Crane
9.5T at 6.5m Boom Length
7T at 8.5m Boom Length

Figure 2.0: Winch

Figure 2.1: Work Wire for the Winch

Figure 2.2: Winding the Work Wire on the Winch Drum

Figure 2.3: Inspecting the Work Wire

Figure 3.0: Main Engine

Figure 3.1: Main Engine Stamp

Figure 3.2: Inconsistent indicators on the main engine control panel

Figure 3.3: Generator Set on board

Figure 3.4: Towing Winch Power Pack

Figure 3.5: Towing Winch Hydraulic Electrical Motor Starter Main Panel

Figure 3.6: Pipe Line Color Chart available in the Engine Room

Figure 3.7: Oily Water Separators

Figure 3.8: Bilge Ballast Pump (Blue) and Fire & G.S Pump (red)

Figure 3.9: Fire & G.S Pump onboard

Figure 3.10: Fire Hose under Inspection

Figure 3.11: Steering Gear Power Pack

Figure 3.12: Steering Gear of the vessel

Figure 3.13: Emergency Lamp in the Steering Gear room

4) OTHER FACILITIES

Figure 4.0: Stairway to accommodation

Figure 4.1: Dining Hall

Figure 4.2: Roller on the Bow side of the vessel (length 3.5m)

Figure 4.3: Deck Panel and the anchor (covered with canvas)

Figure 4.4: Steering wheel and vessel Control Panel

Figure 4.5: Control Panel on the vessel's bridge

Figure 4.6: Radio Operator Station

Wishing For The Star

How I wish I could go for the Basic Offshore Safety Induction and Environment Training (BOSIET). Attending the course alone will cost me around RM1800+ alone excluding the medical checkup. It is a REQUIREMENT by our main client Petronas Carigali Sdn Bhd (PCSB) for anyone working on the work barge to have their BOSIET certificate before applying for the Petronas Smartcard.

Ombak Marine Group just received an Invitation to Bid (ITB) from TL Offshore for a Riser Clamp Project today. Another job to assist with in the upcoming week to prepare the Technical and Commercial Proposal. An ITB is an invitation that the Main Contractor(in this case the Main Contractor will be TL Offshore) will give out to all their registered sub-contractors and one of them is Ombak Marine Group. The client of this project is ExxonMobil. Later the sub-contractor will submit their bid to the company to offer their field of expertise before the submission date set by the Main Contractor. Ombak Marine Group (OMG) field of expertise is currently pipeline trenching, pipeline pre-commissioning and also pipelaying.

So just hope that ExxonMobil wouldn't mind at all about any contractor personnel that don't have any BOSIET certificate to work on their project.

Pipeline Pre-Commissioning Procedure

Figure 1: Typical Pigging Launcher Arrangement

LAUNCHING PROCEDURE

1. Check that the launcher barrel is isolated.
2. Close Trap Valve (9) and Kicker Valve (10) and associated valves (where installed) and bleed through the bleeder valves.
3. Open Vent Valve (2) on launcher barrel and check pressure in the barrel on pressure indicators P1 (1b) and (1c).
4. Open Drain Valve (3) on launcher barrel.
5. When launcher barrel is fully depressurised and drained, release the safety locking device on the launcher barrel trap closure door.
6. Open the launcher barrel trap closure door.
7. Check that the barrel is clean.
8. Insert the pig and pushed it as far as possible (pass the kicker line outlet) using the pig probe.
9. Close and bolt up the launcher barrel trap closure door and secure the security device.
10. Set the pig signaller XI (6a) and (6b).
11. Close the drain valves (3) on the launcher barrel.
12. Close the bleed valve on the kicker line.
13. Open the block valve (10) on the kicker line.
14. Slowly crack open the kicker valve (10) to fill up and equalise the line.
15. Close vent valve when launcher barrel is filled and equalised.
16. Fully open kicker valve (10).
17. Close the bleed valve between the trap valve (9) and block valve (9).
18. Fully open the block valve (9) and trap valve (9).
19. Close the isolation valve (8).
20. Product in line will force the pig into the barrel. The pig will trigger and trip the pig signallers XI(6a) and (6b), which will indicate the pig has gone through the launcher and on its way to the receiver.
21. Fully open the isolation valve.
22. Close the Kicker Valve (10) and the Trap Valve (9).
23. Depressurize the launcher barrel using Drain Valves (3).
24. When fully depressurised and drained, close Vent Valve (2) and Drain Valve (3).
25. Leave the launcher barrel isolated.
26. Inform the receiving party of the successful launch.

RECEIVING AND RETRIEVING PROCEDURE

1. Close Drain Valve (3) and open Vent Valve (2) on the receiver barrel.
2. Open Block Valve (12) and crack open bypass valve (12) to fill up and equalise pressure in the receiver barrel.
3. Close vent valves (2) and check pressure in the barrel on pressure indicators P1 (1b) and (1c).
4. Fully open block valve and trap valve (9).
5. Fully open bypass valve (12).
6. Close isolation valve (8).
7. Set pig signallers XI (6a) and (6b).
8. Receiver barrel ready to receive the pig. Tripping the signaller will indicate that the pig has already arrived in the receiver.
   
9. Fully open isolation valve (8).
10. Close trap valve (9) and bleed off pressure in the receiver barrel. Monitor on pressure indicator P1 (1b) and (1c).
11. Drain the content in the receiver barrel through drain valve (3).
12. When the receiver barrel is fully depressurized and drained, release the safety locking device on the receiver barrel trap closure door.
    
13. Check and remove debris for safe disposal.
14. Remove and check pig for any peculiarity.
15. Close the drain valves (3) and the vent valves (2) on the receiver barrel.
16. Leave the barrel isolated.
17. Inform and report successful retrieval and finding to the Focal Point.
    

Pipeline Trenching Procedure

Pipeline trenching is the normal practice for every pipeline that has been used for the tranportation of oil and gas product from the offshore facility to the onshore facility especially in countries where the water depth is shallow like Malaysia. Trenching are made to protect the pipeline from exposure to any danger that will cause any damage to the pipeline like ship's anchor drag on the seabed. Discussed below is the principle and the procedure related to the post-lay pipeline trenching of an underwater pipeline.

Figure 1: Trencher Machine - Commerce 1

Figure 2: Commerce 1 under Testing

PRINCIPAL OF TRENCHING
The principle of trenching is to create a trench beneath an existing pipeline so that the pipeline will be lowered down into the seabed. The basic steps of trenching are:

1. Hydraulically driven mechanical cutter create two slot on both side of the pipeline.
2. Jets and eductors that are located behind the cutters will fit into the slots created.
3. Cutters will pave the way for the trenching machine to move forward.
4. Cutters will allow jet energy to be concentrated underneath the pipeline in a hard type of clays and underneath and also the side of the pipeline in soft and cohessionless type of soil.
5. Jet manifold incorporates nozzle to direct pressurized water to cut soils underneath and to the side of the pipeline.
6. Certain nozzles will be used depending on the type of soils and also the shape of the trench.
7. Eductors are used to remove the cut and liquefied soils from the trench and deposit soil to the side of the trenching machine. Eductors are powered by the pressurized water.

Trenching machine will move forward and leaves a trench behind and the weight of the pipeline will cause the pipeline to sag down to the bottom of the trench. Stresses on the pipeline are controlled by adjusting the trench depth created on each pass made by the trenching machine. The allowable trench depth is the function of the pipe properties and also the allowable trenching stresses. Hydraulically driven tracks is mounted on the machine for the movement of the machine on the seabed. A dedicated pump usually be equipped on each jets and eductors to provide the necessary presurrized water for the trenching operation. Various hydraulic cylinders are used to adjust the trench depth and height of the cutter, jets and also eductors. The trenching machine will be controlled by an operator for its forward speed, cutter speed, side loads on the pipeline and also the machine direction. The water pressure and flow rates of the jets and the eductors will be adjusted at pump control panel on each of the pump under the direction of the operator. The trenching operation will be performed by the trenching crew located on the baby barge. However, the launching and the recovering operation for the barge will be made using the mother barge since the size of the baby barge is smaller compare to the trenching machine.

ONSHORE AND OFFSHORE SITE PREPARATION
On shore, the Real Time Kinematic (RTK) contorl referance station will be set up, calibrated and fully operational prior to the arrival of the trenching barge at the location while divers will mark the pipeline around the starting location buoys so that it will serve as the visual marker for the barge during setting up at the intended location. The marking shall be completed before the arrival of the trenching barge.

Figure 3: Working Barge POE Giant 7

SETTING AND ANCHORAGE OF BARGE FROM THE START POINT

1. Trenching barge will be towed at the intended location and will be set up approximately 60m from the trencher location.
2. Upon arrival at the visual marked buoy location set up earlier by diver and assisted by the survey team, towing bridle will be switched to anchor cable #1 for final approach and shallow water Anchor Handling Tug (AHT) will deploy anchor #1 at the intended location.
3. The barge will be repositioned close to the shore with the assistance of a tug boat and the utility boat will deplo mooring anchor #3.
4. Shallow water AHT will run anchor #4 and the utility boat will deplot anchor #2 close to the shore. After all the anchor have been deployed barge will be repositioned at intended start-up location.

TRENCHING MACHINE BALLAST TANK
Every trenching machine has its own ballast tank for the purpose of buoyancy to provide acquired depth of trenching depth for every trenching operation. There are some procedures that are usually being practised by the trenching superintendant to float and also to sink the trenching machine for the purpose of the trenching operation.


<>Ballasting Procedure

1. Attach the 2" air and water supply hose to trencher intake line.
2. Make sure 3 of the 2" in line ball valve at left side and 3 at the right side in open position.
3. 3 of the 2" drain ponits ball valve at left side and 3 at the right side in close position.
4. 3 of the 1" air vent point ball valve at lesft side and 3 at the right side in open position.
5. Close the 1" air supply ball valve at main manifold.
6. Open the 2" water supply ball valve slowly to allow water flow to buoyancy tank.
7. Fill-up activities completed when the water flow out at 6 points of the 1" air vent points.
8. Close the 2" air and water supply ball valve.
9. Disconnect the 2" air and water supply hose from trencher.
10. Close all 6 of the the 1" air vent point.
11. Trencher ready to lower down to sea bed by crane.

<> Deballasting Procedure

1. Attach the 2" air and water supply hose to the trencher intake line.
2. Make sure 3 of the 2" in line ball valve at left side and 3 at right side in open position.
3. 3 of the 2" drain points ball valve at left side and 3 at right side in close position.
4. 3 of the 1" air vent point ball valve at left side and 3 at right side in close position.
5. The 2" water supply ball valve in close position (open manifold).
6. Open the 1" air supply ball valve slowly to allow air flow to buoyancy tank.
7. Drain out water completed when the air flow out at 6 points of the 2" drain point.
8. Close the 2" air supply ball valve.
9. Disconnect the 2" air and water supply hose.
10. Close 6 of the 2" drain point ball valve.
11. Trencher ready to lift up by crane to the barge.
    

TRENCHING PROCEDURE

1. The deployment of the trencher machine will be assisted by diver. Once the divers are back on board the work barge, the Superintendent will then commence the full function test of the trenching system.
2. Surveyor will then fine the tune of the Dual Profile to ensure the data obtain from the both profiles are synchronised.
3. Trenching operation will stop after completion of initial 20 meters to allow divers to inspect the status of the trench and to adjust the nozzle if required.
4. The Intergrated Trenching System will go online and ready to resume the trenching operations.
5. The jetting pumps will be restarted and the trenching work will be fully operated. The commencement and relevant monitoring of the trenching operations will be overseen by the trenching superintendent.
6. Diver inspection will be conducted regularly for every 30 meter of trenching to monitor the pipeline and the trench profile as required for the operations. This shall be done by using the pole and feel method to confirm the trench depth.
   

Hydrautically Activated Pipeline Pigging

Another method of pipeline pigging is by using the principle of pressure drop or in other words a Hydrautically Activated Pipeline Pigging (HAPP). The pressure drop is created by blocking the pipeline fluid flow through a by-passable PIGs. The blockage will cause the pressure drop to accelerate the pipeline fluid flow to pass through pig cleaning head. The accelerated pipeline fluid flow will be directed onto the inner wall in front of the PIG to remove all kind of deposits that sticks on the inner wall surface of the pipeline. Using this method, it is like transforming the kinetic energy of the pipeline fluid into a locally available differential pressure which in other words creating a cleaning jets for the PIG.

The components or units that are involved in the HAPP PIG train consists of:
1) Brake Unit
2) Seal Unit
3) Cleaning Head

The PIG train will have an openings that will allow the entire fluid flow through the pipeline to bypass. The Brake Unit will ensure that the Hydrautically Activated PIG to be held back against the fluid flow direction in the pipeline. The fluid that passed through the Brake Unit will then be pushed against the Seal Unit which will channel the fluid flow into the openings located on the Cleaning Head. The situation of blockage made by the Seal Unit and the Brake Unit will cause the pressure difference in the fluid flow itself. The accelerated fluid that enters the cleaning head will be exiting the Cleaning Head through the nozzle to create extremely powerful liquid jets. This powerful liquid jets will be directed to the inner wall of the pipe and this fluid jets will have enough ability to remove any deposits in the pipeline. The Purpose of placing the Brake Unit at the back of the PIG train is to ensure the speed of the Cleaning Head will be controlled that will allow the PIG to remove any deposits before entering the area. The deposit that has been removed by the Cleaning Head Jet Fluid will then be flushed downstream and the total removal of the deposits in the pipeline will reduce the risk or possibility of the PIG getting stuck in the pipeline during the clelaning process.

Introduction to Pipeline Pigging

I have decided to do a deeper research on the Pipeline Inspection Gauge (PIG). Since I have been told that the pipeline pigging process is the most important part in de-commissioning of a pipeline. I have explained briefly on the PIG. Now I would like to add more information regarding PIG.

The function of the Fluid Separation PIG is to separate different type of fluid inside the pipeline during the pigging process. The Fluid Separation PIG will be included in the PIG train during the pigging process. Usually the Fluid Separation PIG are used for a general purpose of pipeline cleaning before applying the hydrotest. The usual fluid that is being used during the pigging process are listed below:

1) Fresh water - for desalination of sea water inside the pipeline
2) Glycol Slugs - dehydration and hydrate inhibition for product introduction
3) Nitrogen Gas - act as a driver medium of the PIG

The cleaning task the PIG can perform are because of the positive interface the PIG has between the pipeline wall surface and the PIG itself. The cleaning effect of the PIG can be enhanced by placing a brush or scrapers on the PIG itself. Some debris that has been produced inside the pipeline are ferrous material which may be removed by installing a magnet on the PIG. The forward action of the PIG will produce a turbulence effect on the fluid which may help in removing small and solid debris from the line while wax and sludges will be removed using PIG that has been installed with brushes and also scrapers.

There are 4 purpose of pigging which are:

1) Pre-commissioning
Pigging is used in the pre-commissioning process to remove the construction debris like welding chip in the pipeline. After removing the debris from the pipeline, hydrotest will be conducted on the pipeline. In this stage, three different PIGs are used namely the cleaning, batching and also gauging PIG. Some pipeline may require further pigging for the purpose of de-watering and also drying operation depending on the medium to be transported in the line.

2) Commissioning
Commissioning pigging is use to separate product in the pipeline from the medium in line using a batching PIG.

3) Operational Pigging
This type of pigging are usually use to mechanically and chemically cleaning the pipeline that has been used from debris like hydrocarbon waxes. Using this method, the flow of the product can still be maintain while minimizing the back pressure produced by the PIG. Batching PIG are used to separate the chemical used for the purpose of cleaning by attaching it in the PIG train. The In Line Inspection (ILI) PIG is use for the purpose of routine maintenance plan.

4) Decommissioning
Decommissioning are usually being used during the process where the pipeline has reached its end life or the pipeline will be used for transporting other type of products. In decommissioning, both mechanical and also chemical cleaning method will be used for the cleaning purpose. For a certain cases, the pipeline will be dewatered for pipeline recovery before it is being reuse.

PIGGING MEDIUMS
There are three normal type of transporting medium being used commercially during the pipeline pigging process.

1) Liquid
- consists of incompressible liquid
- may provide maximum control over the PIG's speed and also provide lubrication for PIG seals
- maximize seal effectiveness and life
- sealing equipments must be compatible with fluid medium, prevailing pressure and flow conditions

2) Gas
- provide more propelling power to drive the PIG
- appropriate consideration towards safety implications during pigging process
- adequate amount of gas required to maintain sufficient pressure to drive the PIG
- possibility of wear increased on the sealing discs

3) Multiphase Fluid
- same safety precaution must be considered as gas propelling medium
- consider slugging effect and associated forces at the receiving end
- temporary pipework should be secured and permanent facilities and equipment should be rated

CRITERIA IN DETERMINING THE TYPE OF PIG
1) Purpose
- type, location and volume of the substance to be removed or displaced in the conventional pigging applications
- type of information to be gathered from an intelligent PIG run
- objectives and goals of the PIG run

2) Line Contents
- content of the line during pigging
- available against required pressure
- velocity of the PIG

3) Characteristics of the pipeline
- minimum and maximum internal line sizes
- maximum distance PIG must travel
- minimum bend radius and bend angles
- other additional features like valve type, branch connections and also elevation profile

TYPE OF PIGS
1) Utility PIGs
> Cleaning PIG - to remove solid or semi solid deposits or debris from pipeline








> Sealing PIG - provide good seal to sweep liquids from line or produce interface between two dissimilar products in pipeline
> Mandrel PIG - have a central body(mandrel) that can be attached with various components for specific duty








> Foam PIG - molded from polyurethane foam with various polyurethane strips permanently bonded between them








> Solid Cast PIG - molded in one piece, usually from polyurethane








> Spherical PIG / Sphere - solid decomposition being inflated into optimum diameter with glycol and/or water








2) Geometry PIGs












PIGs that are designed to record the pipeline conditions like dents, wrinkles, ovality and also bend radius angle. It may be used to detect corrosion in the pipeline by measuring the inside surface of the pipe

3) In Line Inspection (ILI) Tools / Smart PIGs










Provide information on the condition of the pipe to be analyzed by the engineer and the technician. The information that the ILI / Smart PIG can provide are:
> pipe diameter and geometry
> curvature monitoring
> pipeline profile
> temperature or pressure recording
> bend measurement
> metal loss or corrosion detection

4) Plugs

Consider as a specialist PIG that isolate section of pipeline while remedial work is undertaken. This type of PIG may withstand up to 200 bar of pressure. Plugs are grip into the pipeling and it does have a separate sealing system. High Friction PIGs may provide barrier for depressurized systems.

5) Gel PIGs
A series of gelled liquid system developed for the usage of pipeline inspection either as part of the initial commissioning or for further maintenance of the pipeline. Most gel PIGs are water based while some are consists of solvents and other chemical that has been gelled. Gelled diesel are usually used in the gas pipeline. As a liquid, the PIG may entered any type of pipeline which will accept liquid. It can be used together with the other conventional PIGs or to replace the batching PIG in the PIG train. The gel type of PIG may improve the overall performance of the pipeline inspection using PIG as well as to reduce the risk of PIG sticking to each other. There are four main types of gel PIGs which are:

1) Batching or Separator Gel
2) Debris Pickup Gel
3) Hydrocarbon Gel
4) Dehydrating Gel

Gel PIGs will not wear like the conventional PIGs but the gel PIG may susceptible to dilution and also gas cutting. Care must be taken while designing the PIG train that may include the gel PIGs to reduce fluid bypass among the PIGs and to replace a conventional PIG at the back of the train when displacing a gas. Some formulated gels have also been used to seal valves during hydrotesting and also have been developed with controlled gellation and viscosity for temporary pipeline isolation purposes.

Principle of pipeline application of the Gel PIGs are:

1) Product Separation
2) Debris Removal
3) Line Filling / Hydrotesting
4) Dewatering and drying
5) Condensate removal from Gas Lines
6) Inhibitor and Biocide Laydown
7) Special Chemical Treatment
8) Removal of Stuck PIGs

PIG TRAPS/LAUNCHERS/RECEIVERS
PIG traps are used to insert the PIGs into a pipeline before launching, receiving and finally removing it without interrupting the product flow in a pipeline. Usually a PIG trap are not generally a proprietary products and the specification are drawn up by the user but the closure of the PIG trap are proprietary and important part of the pigging system. Safety is the main consideration in choosing the PIG trap closure at which the closure must be built with safety lock to prevent the closure be opened while the trap is pressurised.