natural gas n: a highly compressible, highly expansible mixture of
hydrocarbons with a low specific gravity and occurring naturally in a gaseous
neutron log n: a radioactivity well log used to
determine formation porosity. The logging tool bombards the formation with
neutrons. When the neutrons strike hydrogen atoms in water or oil, gamma rays
are released. Since water or oil exists only in pore spaces, a measurement of
the gamma rays indicates formation porosity. See radioactivity well logging.
night toolpusher n: an assistant toolpusher whose
duty hours are typically during nighttime hours. Also known as a tourpusher.
nipple n: a tubular pipe fitting threaded on both
ends used for making connections between pipe joints and other tools.
nipple up v: in drilling, to assemble the blowout
preventer stack on the wellhead at the surface.
nitro shooting n: a formation-stimulation process
first used about 100 years ago in Pennsylvania. Nitroglycerine is placed in a
well and exploded to fracture.
normal circulation n: the smooth, uninterrupted
circulation of drilling fluid down the drill stem, out the bit, up the annular
space between the pipe and the hole, and back to the surface.
nozzle n: 1. a passageway through jet bits that
causes the drilling fluid to be ejected from the bit at high velocity.
nuclear log n: see radioactivity log.
nuclear tracer n: a gas, liquid, or solid material
that emits gamma rays.