American Petroleum Institute (API)



Api County Code

Api State Code 

Api Well Number 

Appraisal Well 

Associated Gas








Blow-out preventers (BOPs)





Casing string

Central estimate

Christmas tree



(1) The proper plugging and abandoning of a well in compliance with all applicable regulations, and the cleaning up of the wellsite to the satisfaction of any governmental body having jurisdiction with respect thereto and to the reasonable satisfaction of the operator.(2) To cease efforts to find or produce from a well or field.(3) To plug a well completion and salvage material and equipment.

(1) The act or process of reducing the intensity of pollution.(2) The use of some method of abating pollution.

The American Petroleum Institute is the primary trade association representing the oil and natural gas industry in the United States.

The space between: (1) The casing and the wall of the borehole.(2) Two strings of casing.(3) Tubing and casing.

American Petroleum Institute

An indicator developed by the American Petroleum Institute (API) to identify areas such as counties and other subdivision areas identified within state boundaries. Defined by API Bulletin D12A, as amended. This code becomes a part of the API Well Number.

The indicator assigned to a state, as defined in API Bulletin D12A, as amended. This code is a part of the API Well Number (The Api State Code for Colorado is 05).

Api Well Number A well identifier assigned as defined in API (American Petroleum Institute) Bulletin D12A, as amended. The API Well Numbers are assigned by the appropriate state or federal regulatory agency.

A well drilled as part of an appraisal drilling program which is carried out to determine the physical extent, reserves and likely production rate of a field.​

A well drilled as part of an appraisal drilling program which is carried out to determine the physical extent, reserves and likely production rate of a field.

A unit of volume measurement used for petroleum and its products (7.3 barrels = 1 ton: 6.29 barrels = 1 cubic meter).

One barrel of oil; 1 barrel = 35 Imperial gallons (approx.), or 159 liters (approx.); 7.5 barrels = 1 ton (approx.); 6.29 barrels = 1 cubic meter.

Billion cubic feet; 1 bcf = 0.83 million tons of oil equivalent.

Billion cubic meters (1 cubic meter = 35.31 cubic feet).

An acreage sub-division measuring approximately 10 x 20 kms, forming part of a quadrant. e.g. Block 9/13 is the 13th block in Quadrant 9.

Condensate and gas is produced simultaneously from the outset of production.

When well pressure exceeds the ability of the wellhead valves to control it. Oil and gas “blow wild” at the surface.

Are high pressure wellhead valves, designed to shut off the uncontrolled flow of hydrocarbons.

See blow-out preventers

The hole as drilled by the drill bit.

A casinghead.

Pipe cemented in the well to seal off formation fluids or keep the hole from caving in.

The steel tubing that lines a well after it has been drilled. It is formed from sections of steel tube screwed together.

A range of exploration drilling scenarios from which the following activity levels, based on recent historical experience, are adopted as the central estimates.

The assembly of fittings and valves on the top of the casing which control the production rate of oil.

Colorado Oil and Gas Conservation Commission

Colorado Oil and Gas Information Systems