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Why are there duplicate API numbers?

Although the API Number is commonly used as a unique well identifier, some states allow duplicate API numbers. This article explains why duplicate API numbers exist and why the WellDatabase Infinity ID is the recommended identifier for long-term record linking.

Some states assign wells using a unique serial number rather than relying solely on the API Number. As a result, multiple wells may share the same API Number while remaining separate well records. 

Why Duplicate API Numbers Exist

In most states, the API Number uniquely identifies a well. However, some states use an additional state-assigned serial number as the unique identifier.

Because of this, more than one well may share the same API Number while being distinguished by different state serial numbers.

For example:

Although the API Numbers are identical, these represent two different well records because each has a different state serial number.

States That Allow Duplicate API Numbers

The following states may have duplicate API Numbers:

  • Idaho
  • Kansas
  • Kentucky
  • Louisiana 

Recommended Identifier

Although the API Number is the industry-standard identifier and is appropriate for most workflows, WellDatabase recommends using the WellDatabase Infinity ID when linking records to internal systems, data warehouses, reports, exports, or third-party applications. 

The WellDatabase Infinity ID uniquely identifies a WellDatabase record and is not affected by duplicate API Numbers.

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Frequently Asked Questions

Q: I thought API Numbers were always unique. Why are there duplicates?
A: Most states use the API Number as a unique identifier. However, some states assign a separate state serial number that distinguishes wells sharing the same API Number.

Q: Does a duplicate API Number indicate a data issue?
A: No. In states that allow duplicate API Numbers, multiple wells may legitimately share the same API Number while remaining separate well records through their state-assigned serial numbers.

Q: What identifier should I use when integrating WellDatabase data with another system?
A: We recommend using the WellDatabase Infinity ID whenever possible. The Infinity ID uniquely identifies a WellDatabase record and avoids issues caused by duplicate API Numbers or well name changes.

Q: Should I use the API Number or the WellDatabase Infinity ID?
A: The API Number remains the industry-standard identifier and is appropriate for most workflows. However, when integrating WellDatabase data with other systems or maintaining long-term record relationships, we recommend using the WellDatabase Infinity ID because it uniquely identifies each WellDatabase record. 

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