An abbreviation for ‘pipeline inspection gauges’, pigs are used to assess internal pipeline conditions, to clean, and perform maintenance, known as pigging. The name is thought to derive from the squealing sounds early devices made.


Pipeline end manifold.


Pipeline end termination. A termination structure between the main pipeline and a rigid spool or flexible jumper.


Pressurized mud-cap drilling. One of four common drilling techniques in MPD, used to mitigate fluid loss when drilling in depleted zones or formations with fractures or large voids, such as caverns. All drilling fluids and gases produced are returned to the formation during drilling, maintaining pressure in the formation and the annulus fluid column. This mitigates drilling hazards such as fluid loss, kicks and differential sticking. PMCD deduces costs and NPT, and improves safety.

Pressure gradient variations

Pressure gradient variations occur due to the presence of multiple formations, each with its own pore and fracture pressure. As different types of rock are drilled, it becomes necessary to set casing to isolate low pressure zones from higher pressure zones.


The process of bringing formation fluids to surface in order to process hydrocarbons for sale.


Pressure relief value is a required safety device that releases gases and liquids to control or limit pressure within a system or a vessel.