دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

annular isolation sleeve.

n: in tank sampling, a sample that is obtained by submerging a stoppered beaker or bottle to a poinias near as possible to the draw-off level, then opening the sampler and raising it at a rate that makes it about three-quarters full (maxi- mum 85%) as it emerges from the liquid.

n: a substance, such as tetraethyl lead or other compounds, added to the fuel of an internal-combustion engine to prevent detonation of the fuel. Antiknock compounds effectively raise the octane rating of a fuel so that it burns properly in the combustion chamber of an engine. See octane rating, tetraethyl lead.

n: a well drilled to confirm and evaluate the presence of hydrocarbons in a reservoir that has been found by a wildcat well.

additional wells drilled after a discovery, to confirm the size of a hydrocarbon deposit. Normally used to run buildup tests, drill stem tests, top and bottom of formation, gather core or fluid samples or other evaluations.

n: a mobile submersible drilling structure used in arctic areas. The rig is towed onto the drilling site and submerged during periods when the water is free of ice. All equipment below the waterline is surrounded by a caisson to protect it from damage by moving ice. The drilling deck has no square comers so that moving ice can better flow around it. See submersible drilling rig.

n: any method used to raise oil to the surface through a well after reservoir pressure has declined to the point at which the well no longer produces by means of natural energy. Sucker rod pumps, gas lift, hydraulic pumps, and submersible electric pumps are the most common means of artificial lift.

one of several methods that provide pressure assistance to increase flow from a well. The most common systems lighten (decrease density) of the flowing fluid (gas lift),or remove all or part of the liquid head from the reservoir (beam and electric submer

n: The valve in the bottom of bailer. The valve is opened when the bailer in the bottom of well and closed when the bailer raises.

a build-up of particles on the upstream side of a filter that improves the filter’s ability to remove particles from fluid (will also raise the differential pressure across the filter).

n: any assembly of pulleys on a common framework;in mechanics. one or more pulleys. or sheaves. mounted to rotate on a common axis. The crown block is an assembly of sheaves mounted on beams at the top of the derrick or mast. The drilling line is reeved over the sheaves of the crown block alternately with the sheaves of the travelling block. which is hoisted and lowered in the derrick or mast by the drilling line. When elevators are attached to a hook on a conventional travelling block. and when drill pipe is latched in the elevators. the pipe can be raised or lowered in the derrick or mast. See crown block, travelling block.