Decommissioning Insight 2016 - Oil & Gas UK

DECOMMISSIONING INSIGHT REPORT 2016

In relation to wells, these may be referred to as a subsurface safety valve (SSSV). This is a safety device installed in the upper wellbore to provide emergency isolation of the producing fluids in the event of an emergency. Two types of subsea isolation valves are available: surface-controlled and subsurface controlled. In each case, the safety valve system is designed to be fail-safe, so that the wellbore is isolated in the event of any system failure or damage to the surface production-control facilities. In subsea facilities, isolation valves are included in the seabed manifold to isolate wells and piping to protect facilities in the event of an emergency or routine need to prevent fluid flow. Subsea tie-backs usually connect small reservoir accumulations, developed using subsea trees and manifolds, back to a host platform for onward processing and or transportation. Trunklines are defined as pipelines with a diameter greater than 14 inches and a length in excess of 18 kilometres. Usually referred to as production (or injection) tubing. This is a pipe inserted in the well to carry and contain the production (or injection) from the reservoir to the surface.

Subsea isolation valves

Subsea tie-back

Trunkline

Tubing

UK Continental Shelf Utility support pipes

UKCS

Umbilical

The removal and decontamination of scale build-up that deposits in the tubing of a well during production of reservoir fluids.

Well-scale decontamination

Well Plugging and Abandonment

Well P&A

The wellhead is the termination point where the casing strings in the well are supported and provide pressure containment. A form of well intervention that uses an electrical cable to lower tools into the borehole and to transmit data to the surface.

Wellhead

Wireline

West of Shetland

W o S

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