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API Well Number

A distinct 12-digit number assigned to a U.S. well.  Digits 1 and 2 are state codes, 3-5 are county/parish or offshore codes, digits 6-10 identify the well and digits 11-12 identify special well conditions such as sidetracking.

How it’s important to us

The API # is a piece of data tracked almost universally through all well-centric applications and departments.  Because it’s the government’s unique identifier, it is also a great way to link wells across systems.  API stands for “American Petroleum Institute”.  While the technical definition suggests that API # is unique, often the same 12-digit API prefix is used for and a 3-character “completion suffix” is tagged on when a well is re-completed.


Nate Richards
Nate has over 18 years of software engineering and consulting experience. He founded Entrance in 2003. Nate is the past President of the Board of LifeHouse Houston, a Christ-centered maternity home ministry, and is past Executive committee member and Treasurer of Houston Achievement Place, a foster care and social skills training non-profit organization.
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