API Well Number

An API well number is a standardized identifier used in U.S. oil and gas records. The name reflects the American Petroleum Institute's numbering standard; it does not mean the Institute assigns every well number. State and federal regulatory systems administer identifiers under their own conventions.

Short Answer

Use the API number to help match well records, but check both the source format and the reporting level. A well, wellbore, completion, and production lease are not interchangeable records.

Structure of the API Number

The common 10-digit base combines a two-digit state code, three-digit county code, and five-digit well identifier. Some datasets add two-digit suffixes for wellbore or completion detail.

This is a formatting illustration, not a verified well lookup. Do not assume an API county code is interchangeable with every other geographic coding scheme.

API-10 vs. API-12 vs. API-14

A source may publish the 10-digit base, a 12-digit identifier, or a 14-digit identifier. Texas RRC well-record queries also use an eight-digit form: the three-digit county code plus five-digit well identifier, without the state prefix.

Store identifiers as text so leading zeroes survive. Preserve the original identifier and normalize punctuation into a separate matching field. Consult the source documentation before interpreting suffixes.

Do not simply truncate every number to ten digits and merge the results. That can combine distinct wellbores or completions and duplicate production.

Example Workflow

Texas oil production can require lease-level joins. An API match alone does not allocate lease production to a specific well.

Why It Matters for Data Users

Operator and well names can change, so API identifiers are valuable matching inputs. They are not a universal guarantee of a one-to-one join. Retain source keys, operator IDs, lease identifiers, reporting periods, and match confidence where the workflow requires them.

Sources

• Texas RRC Well Records FAQs
• EnergyNetWatch methodology