V

Velocity Stack: A long tube used in well re ghting operations to move all the ¤uids and the re up above the damaged wellhead. May also be used to put out the re in some cases. Velocity String: A small-diameter tubing string, often coiled tubing that is suspended inside the existing production tubing. By occupying part of the ¤ow path space, the velocity of the produced ¤uid is increased, and the potential to lift water from the well is increased. Vent: Release gas pressure. Vented: Gas released into the air on the base site or at processing plants. Ventilator: Device for replacing air inside a room by outside air. Vent Screen: A length of tubing with a screen at each end, intended to be installed through tubing and half of the assembly covered with gravel. A common repair for a breached screen. Generally low rate. Venturi: A shaped nozzle. Veri–cation: Tool surface operational check. Vertical Depth: Vertical extent of a depth measurement. Vertical Seismic Pro–le: Run in a single wellbore. Helps correlate logs with seismic data. Vertical Tree (Subsea): A subsea tree with the master valve above the tubing hanger. Very Large Crude Carrier: Oil transportation vessel from 200,000 to 320,000 dwt. Also see Large range (LR) and very large crude carriers. V-G Meter: Fann viscosimeter. VI: See Viscosity index. Vibroseis: (1) The process of producing seismic shock waves with “thumpers” or vibrator vehicles. (2) A seismic survey where the energy is generated by vibrators attached to large truck-mounted plates at the surface. Vinyl Acetate: (1) Vinyl acetate is a colorless, clear liquid with a sweet fruity smell; it does not occur naturally in the environment. Vinyl acetate readily evaporates into air and dissolves easily in water; it is ¤ammable and may be ignited by heat, sparks, or ¤ames. It is primarily used in the production of polyvinyl acetate and polyvinyl alcohol, which are widely used in adhesives for packaging and construction and in water-based paints. (2) A common monomer used to make chain-growth polymers.