Oil & Gas Terms in Category N


Abbreviation: national association of corrosion engineers.

Normal formation pressure

Formation fluid pressure equivalent to about 0.465 pounds per square foot of depth from the surface.

If the formation pressure is 4,650 pounds per square inch at 10,000 feet, it is considered normal.


A chart that presents an equation containing a number of variables in the form of several straight lines.

The straight lines are scaled with values of the variables.

To use it, a straight edge is placed across the scaled lines at the appropriate values.

A nomograph can be easier to use than solving the equation.


A reaction in which the hydrogen ion of an acid and the hydroxyl ion of a base unite to form water, the other ionic product being salt.

Natural completion

A completion that is not stimulated.


An inert gas used for jetting wells.

Natural gas

A mixture of hydrocarbons and varying quantities of nonhydrocarbons that exist either in the gaseous phase or in solution with crude oil in natural underground reservoirs.

Nonconductive mud

Any drilling fluid, usually oil-base or invert-emulsion muds, the continuous phase of which does not conduct electricity, e.g., oil.

Natural gasoline

The liquid hydrocarbons recovered from wet natural gas, i.e., casinghead gasoline.

Normal pressure gradient

The normal pressure divided by true vertical depth.

Neat cement

A cement with no additives other than water.

Natural gas liquids

Those portions of reservoir gas which are liquefied at the surface in field facilities or gas processing plants.

National association of corrosion engineers (nace)

An organization whose function is to establish standards and recommended practices for the field of corrosion control.

Nitro shooting

A formation-stimulation process first used about a hundred years ago in pennsylvania.

Nitroglycerine is placed in a well and exploded to fracture the rock.

Sand and gravel or cement is usually placed above the explosive charge to improve the efficiency of the shot.

Nitro shooting has been largely replaced by formation fracturing.



A passageway through jet bits that causes the drilling fluid to be ejected from the bit at high velocity.

The jet of mud clears the bottom of the hole.

Nozzles come in different sizes that can be interchanged on the bit to adjust the velocity with which the mud exits the bit.


The part of the fuel system of an engine that has small holes in it to permit fuel to enter the cylinder.

Properly known as a fuel-injection nozzle, but also called a spray valve.

The needle valve is directly above the nozzle.