US Well Number Standard

This standard is for the identification of petroleum wells in the USA. The US Well Number is a 12-digit number assigned to every wellbore; it includes the unique identity of a well. It is a foundation for the management and exchange of all information about wells.
The US Well Number is the official successor to the API Well Number from the American Petroleum Institute (API). In 2010, the API transferred custody of their standard to the PPDM Association. The new standard provides continuity with the API Number while addressing some challenges that have evolved in the past four decades: well designs and data flows have become more complex, safety and environmental risks have increased where unidentified wellbores are present, and data exchange is difficult if identifiers are assigned inconsistently.

US Well Number

PDF (2.2 MB) - Full Detail

Well Identification
US Booklet

PDF (5.9 MB) - Summary

List of State & County Codes

PPDM Association US State by State comparison of unique well identification (UWI) practices

This is an unofficial compilation of how regulators in the USA identify wells and wellbores. The information contained in this report is known to be out of date and is available for legacy purposes only. The PPDM Association has no liability for errors or omissions to this content.
Revised on: August 24, 2015