Wednesday, April 7, 2010

PIG is not an animal

From observation and few ask-around session in the office today, I manage to learn more about the oil and gas industry. The oil rig and pipeline construction has a lot of acronyms that are needed for the engineers to understand the terms and its meaning. Firstly I want to discuss about Pipeline Inspection Gauge (PIG). There will also be a brief discussion on the difference between an Oil Rig and also Oil Platform.


Pipeline Inspection Gauge (PIG)
The name came from the squeling sound it made while travelling through the pipeline during operation. PIG are used to perform various operations without stopping the product flow inside the pipeline. A PIG launcher is installed in the Y-shaped funnel section in a pipeline and usually a PIG are check very ocassionally but will remain to shuttle up in the pipeline. Installation of a PIG inside the pipeline has a certain purposes in the pipeline. In the Oil and Gas industry, the purposes of installing the PIG inside a pipeline and also the type of PIGs used for the purposes stated are listed below:

1) Bullet shaped polyurethane foam type of PIG are used for the purpose of separating different products of oil in a multiproduct pipeline.
2) Tungsten studs or an abrasive wire mesh are used for the purpose of internal pipe cleaning to remove contaminants like wax, foreign objects, hydrants etc.
3) SMART PIGS are used to inspect the pipelines for its geometry and also data recording for later analysis using Magnetic Flux Leakage (MFL), ultrasonic and some PIGs are equipped with calipers for geometry measuring purpose.

The safety issues when a PIG is installed along the pipeline is:
1) Pipeline must be depressure to ensure that the PIG will not be boost out of the pipeline and injured the workers
2) When the product is sour, the flare system must be placed to ensure all the sour gases be burnt

The advantage of installing a PIG inside a pipeline is
1) potential resulting product separation
2) much more rapid and reliable product changeover
3) reduce the usage of chemical solvent for cleaning purposes


Example of a PIG

Derrick Lay Barge (DLB)
DLB are used for the purpose of laying the pipeline and also to help during the installation of the platform of an oil rig or an oil platform. There are many types of DLB used in the Oil and Gas Industry. Some DLB may only execute the pipelay operation, some types may do the derrick job and lastly there are types of DLB that may do both the derrick and also the pipelaying job. DLB differs from the normal utility barge by its size and also its features. DLB usually being installed with a derrick and other construction utilities on the barge but the normal utility barge platform is usually empty and the construction utilities placed on top of it can be customised according to the need of the project.















Figure of a DLB

Remotely Operated Vehicle (ROV)
ROV is considered as an unmanned vehicle that are usually used for the purpose of underwater exploration and also for survey job especially for offshore hydrocarbon extraction exploration. Certain ROV may have the ability to to do underwater construction work. ROV are usually unoccupied, highly maneuverable and being controlled by a person on a vessel where the ROV will be connected to the vessel by a tether. Tether is a group of cable carrying electrical power, video and data signals back and forth between the operator and also the vehicle. Some ROV which may require high power applications will include hydraulics cable inside the tether. Equipments that are usually being installed on the ROV are:

1) Video camera
2) Lights
3) Sonars
4) Magnetometer
5) Manipulator or cutting hand
6) Water sampler

The ROV can be classified into its own category based on the size and also the ability of the ROV to finish a task. Listed below is the classification of ROV and its descriptions:

1) Micro
Usually less than 3kg. Used for exploration in small spaces that may not be entered by divers like sewer, pipeline and also small cavity.

2) Mini
Approximately 15kg. Being referred as an 'Eyeball' as well as the Micro ROV. Usually may be operated without any outside help.

3) General
With a propulsion power of less than 5HP, this type of ROV usually being installed with small three fingers manipulators and also gripper. It may carry sensor and usually used for light survey applications. Maximum work depth is less than 1000m.

4) Light Workclass
Propulsion power less than 50HP, it may carry some manipulators. Its chassis usually made from polymer like polyethylene instead of aluminium. Working depth to be at less than 2000m.

5) Heavy Workclass
With less than 220HP prpulsion power, this type of ROV may be installed with two manipulators and may be able to work for the sea depth of 3500m and below.

6) Trenching/Burial
Propulsion power in between 200HP and also 500HP, this class of ROV usually be installed with a cable laying sled on the bottom side. Its working depth believe to be up to 6000m depth.

For an Oil and Gas industry, the most widely used ROV are the Construction ROV which usually include a large flotation pack on top of the aluminium chassis that may provide enough buoyancy for the ROV. Usually a synthetic foam are used for the flotation purpose and a tool sled may be fixed on the ROV for the accomodation of the sensor. The orientation of the Construction ROV of light components on the top side and also heavy components on the bottom side are to produce a large separation between the center of buoyancy and the center of gravity. The large separation between this two are useful to create stability and also stiffness for underwater operations. Electrical cables that supply electrical power and also other type of cable may be placed in an oil filled tube to avoid corrosion to occur to the cables itself. Lastly a Construction ROV are included with a thruster for all the axes for full control of the ROV.















Figure of ROV

Oil Rig
The function of an oil rig is basically on the oil reservoir exploration. Oil rig usually will float to the designated location that has been located by the surveyor to do the drilling work. After the drilling work has been done, the drill hole that link the sea bed and the oil reservoir will be sealed and the oil rig will float to another location for oil exploration and drilling work.

Oil Platform
Oil Platform is a platform that will do the extraction job from the oil wells that has been made by the exploration oil rig. The crude oil that has been extracted from the oil reservoir through the oil wells will then be stored and will be supplied to the oil tanker through the Floating Production Storage and Offloading (FPSO) or directly to the onshore reservoir through the pipeline.





















Figure of an Oil Platform



This is as much information I can provide the reader this time around. I will provide with a more interesting details and explanations regarding the Oil and Gas Industry on my next post and also to share the experience that I have gain during my Industrial Training period in Ombak Marine Group Sdn Bhd.

No comments:

Post a Comment