Oil & Gas Terms in Category A




American petroleum institute

(api) a trade association founded in 1919 with offices in washington, dc, usa.

The api is sponsored by the oil and gas industry and is recognized worldwide.

Among its long-term endeavors is the development of standardized testing procedures for drilling quipment, drilling fluids and cements, called api recommended practices (“rps”).

The api licenses the use of its monogram (logo), monitors supplier quality assurance methods and sets minimum standards for materials used in drilling and completion operations, called api specifications (“specs”).

The api works in conjunction with the international standards organization (iso).

Absolute open flow

Or aof.

The maximum rate that a well can produce at the lowest possible bottom hole pressure.

Absorb, absorption

1.to take in or make part of an existing whole.


To recover liquid hydrocarbons from natural or refinery gas in a gas-absorption plant.

The wet gas enters the absorber at the bottom and rises to the top, encountering a stream of absorption oil (a light oil) traveling downward over bubble-cap trays, valve trays, or sieve trays.

The light oil removes, or absorbs, the heavier liquid hydrocarbons from the wet gas.


To soak up as a sponge takes water.



American petroleum institute



Authorization for definition.

Apparent viscosity


The viscosity of a fluid measured at a given shear rate at a fixed temperature.

In order for a viscosity measurement to be meaningful, the shear rate must be stated or defined.


The viscosity of a fluid measured at the shear rate specified by api.

In the bingham plastic rheology model, apparent viscosity (av) is one-half of the dial reading at 600 rpm (1022 sec-1 shear rate) using a direct-indicating, rotational viscometer.

For example, a 600-rpm dial reading is 50 and the av is 50/2, or 25 cp.

Absorption oil

A hydrocarbon liquid used to absorb and recover components from natural gas before being processed.

Absolute humidity

The amount of moisture present in the air, usually expressed in grains of water per 100 cubic feet of air (milligrams of water per cubic meter of air).


The process of sucking up; taking in and making part of an existing whole.

Compare adsorption.

Alkaline flooding

Large scale injection of ph>7 fluids.

The basic materials may react with oils to form reactants that can reduce viscosity or affect wetting.

Absolute pressure

Total pressure measured from an absolute vacuum.

It equals the sum of the gauge pressure and the atmospheric pressure corresponding to the barometer (expressed in pounds per square inch).


(az) the compass direction of a directional survey or of the wellbore as planned or measured by a directional survey.

The azimuth is usually specified in degrees with respect to the geographic or magnetic north pole.


American association of petroleum landmen

Absorber capacity

The maximum volume of natural gas that can be processed through an absorber at a specified absorption oil rate, temperature, and pressure without exceeding pressure drop or any other operating limitation.