Related Oil & Gas Terms

• Seismic survey

  An exploration method in which strong low-frequency sound waves are generated on the surface or in the water to find subsurface rock structures that may contain hydrocarbons. the sound waves travel through the layers of the earth’s crust; however, at formation boundaries some of the waves are reflected back to the surface where sensitive detectors...

• Scratcher

  A device that is fastened to the outside of casing to remove mud cake from the wall of a hole to condition the hole for cementing. by rotating or moving the casing string up and down as it is being run into the hole, the scratcher, formed of stiff wire, removes the cake so that...

• Wireline formation tester

  A formation fluid sampling device, actually run on conductor line rather than wireline, that also logs flow and shut-in pressure in rock near the borehole. a spring mechanism holds a pad firmly against the sidewall while a piston creates a vacuum in a test chamber. formation fluids enter the tes5t chamber through a valve in...

• Perforation

  A hole made in the casing, cement, and formation through which formation fluids enter a wellbore. usually several perforations are made at a time....

• Abnormal pressure

  1. pressure exceeding or falling below the normal pressure to be expected at a given depth. normal pressure increases approximately 0.465 psi per foot of depth (10.5kpa per meter of depth). thus, normal pressure at 10,000 feet is 4,650 psi; abnormal pressure at this depth would be higher or lower than 4,650 psi. see pressure...