Potential Revisions To The API Numbering System

Oil and gas operators understand that each well is identified by a unique "API" number, however many do not understand how the well numbering system in the US works -- nor that changes may be coming. Here is a short course on how the system works and where it may be going.

API Numbers were established by the American Petroleum Institute in 1962 and grew out of the Institute's Well History Control System product which was first offered in 1956. There have been several revisions to the standard, most recently in 1979 in API Bulletin D12A-79. Further modifications to the standard were drafted in 1995, but those revisions were never published or adopted. Thus, the 1979 standard is still in effect, although the publication is no longer available directly from the API.