Decommissioning Insight 2017

6. Glossary


Association for the Advancement of Cost Engineering

Barge-launched jackets weigh between 5,000 and 25,000 tonnes. They are yard fabricated and transported horizontally to the field on a transportation barge, then launched from the barge over rocker beams and upended through controlled flooding. Final positioning may require crane assistance. Pipe installed in the wellbore to retain the borehole dimension and seal off hydrocarbon and water-bearing formations. Casing is usually cemented in place to ensure the pipe remains in place. The valves and fittings assembled at the top of a completed well. A long continuous length of pipewound on a spool. The pipe is straightened prior to pushing into a wellbore and rewound to coil the pipe back onto the transport and storage spool. Used to compare options, examine differences and identify the ‘most preferred’ option in the development of decommissioning programmes for: a) All installations for which derogation is sought under OSPAR Decision 98/3 b) All pipelines being decommissioned under the Petroleum Act 1998 c) All drill cuttings piles that are not screened-out at Stage 1 of OSPAR A large diameter pipe extending upwards from or beneath the seafloor to the top of the well on the platform. The purpose of the conductor is to act as a guide for drilling the well and a protective barrier from the elements for the well casings and tubing during the life of the well. A structure used to support crown blocks and drilling string of a rig. Leaving infrastructure in place and carrying out appropriatework to ensure that there is minimal risk to other sea users or the marine environment. This could apply to any installed facilities on the seabed, such as pipelines, manifolds, pipeline crossings and the footings of larger jackets. Energie Beheer Nederland is a company that invests in the exploration, extraction and storage of gas and oil on behalf of the Dutch State. Flexible flowlines usually transport hydrocarbons between subsea infrastructure and the host platform or vessel. They are manufactured from composite layers of steel wire and polymer sheathing that provide protection and flexibility to the flowline. The addition of wells in a field that decreases average well spacing to accelerate expected recovery and increase estimated recovery in heterogeneous reservoirs. Fixed rig installed at the well location, usually self-contained, with steel or concrete legs anchored to the seafloor. Well servicing operations conducted within a completed wellbore to restore or improve production or injection. Central North Sea Cessation of production Floating, production, storage and offloading vessel.

Barge-launched jacket


Christmas tree


Coiled tubing

Comparative assessment




Drilling derrick

Decommissioning in situ


Flexible flowlines


Infill drilling

Integral rig



Made with FlippingBook - Online Brochure Maker