Common Questions on Oil and Natural Gas Industry

This post shares the most common questions and answers on oil and natural gas industry for the young engineers for their technical job preparation.

Questions on Oil and Natural Gas Industry

Common Questions on Oil and Natural Gas Industry

What is a Blank flange (blind)?

A component for closing an open end of pipework, which is suitably rated to maintain the pressure rating of the pipe and of an appropriate material to withstand the contents of the line.

What is a Bleed or vent valve?

A valve for draining liquids or venting gas from a pressurised system.

What is a block valve?

A valve which provides a tight shut-off for isolation purposes.

What is a double block and bleed (DBB)?

An isolation method consisting of an arrangement of two block valves with a bleed valve located in between.

What is a double-seated valve?

A valve which has two separate pressure seals within a single valve body. It is designed to hold pressure from either direction (as opposed to a single seated valve). It may include a body vent between seals to provide a block and bleed facility.

What is an extended isolation?

Isolation which is to remain in place for more than three months.

What is fluid?

Freely moving substance. Includes liquids and gases.

What is hazardous substance?

A substance which is able to cause harm or damage if loss of containment occurs. In some cases (eg water) the specific situation determines whether the substance belongs within this category.

What is intolerable risk?

Risk at an unacceptably high level. Until the risk has been reduced, activity should not be started (or continued). If the risk cannot be reduced, even with unlimited resources, the proposed activity should not go ahead.

What is isolating authority?

Person authorised to approve proposed isolations.

What is isolation?

The separation of plant and equipment from every source of energy (pressure, electrical and mechanical) in such a way that the separation is secure.

isolation envelope that part of the pipework system which is within the isolation points forming the boundary within which intrusive work can be performed. Where a valved isolation allows a physical isolation to be effected, it is the physical isolation point that forms the boundary of the isolation envelope.

What is isolation envelope?

that part of the pipework system which is within the isolation points forming the boundary within which intrusive work can be performed. Where a valved isolation allows a physical isolation to be effected, it is the physical isolation point that forms the boundary of the isolation envelope.

What is isolation scheme?

A system incorporating three key components – management arrangements, risk control procedures and working-level practices, to ensure hazardous substances are not released nor people exposed to risks to their health and safety during the maintenance or repair of process plant or pipelines.

What is own isolation?

Isolation where the same person both installs the isolation and carries out the intrusive work. Such isolations may be carried out under PTW or procedural control.

What is permit-to-work (PTW)?

A formal written system used to control certain types of work which are hazardous.

What is pig?

A device that can be driven through a pipeline by means of fluid pressure for purposes such as cleaning, dewatering, inspecting, measuring, etc.

What is physical disconnection?

A method of positive isolation where an air gap between the energy source and the plant/equipment is provided.

What is pipeline?

The definition of ‘pipeline’ is the facilities through which fluids are conveyed, including pipe, pig traps, components and appurtenances, up to, and including the isolation valves’. However, pipeline installations such as compressor stations and pressure- regulating installations are not included in this definition – these are considered separately.

What is pipeline installation?

Installations such as pressure regulating installations, compressor stations which, together with the pipeline itself, comprise a pipeline system.

What is pipework?

Piping interconnecting items of process plant.

What is piping and instrumentation diagram (P&ID)?

A schematic drawing defining the extent of equipment, piping and piping components and instrumentation.

What is positive isolation?

A complete separation of the plant/ equipment to be worked on from other parts of the system.

What is pressurised plant?

Facilities containing liquid or gases under pressure for treatment, processing or storage.

What is proved isolation?

Valved isolation where effectiveness of the isolation can be confirmed via vent/bleed points before breaking into system.

What is short-duration work?

Work which does not extend beyond one operating shift.

What is slip-ring?

A spacer ring installed in pipework to facilitate the insertion of a spade.

What is spade (slip-plate)?

A solid plate for insertion in pipework to secure an isolation. The spade must be of an appropriate material to withstand the line contents.

What is spared equipment?

Equipment which is available to replace on-line equipment, eg during maintenance or in the event of breakdown.

What is spectacle plate?

A combined spade and slip-ring.

What is tagging?

Temporary means of identifying a valve or other piece of plant.

What is variation?

A situation where circumstances require the use of an isolation of a standard lower than the baseline isolation standard (or where relevant, the established company standard).

Use of a variation is acceptable only when it is supported by a situation-specific risk assessment. Variations must be appropriately authorised and fully recorded.

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