Landman Business | October 5, 2026 | 11 min read
Well identifiers look like dependable database keys until a recompletion, sidetrack, jurisdictional format, operator conversion, or legacy record exposes their limits. A well identifier change crosswalk should preserve those differences and document why two records are related. Its purpose is controlled retrieval and system mapping—not declaring that nearby records represent the same legal or physical well.
well identifier change crosswalk: Start by naming the object
Before comparing numbers, define what each identifier identifies. Depending on the source, a number may refer to a surface location, wellbore, completion, permit, producing entity, facility, or filing. Two identifiers can both be correct while describing different levels of that hierarchy.
Create a source dictionary for every system in scope. Record the issuing authority, field label, displayed format, documented meaning, searchable variants, source link, and access date. Do not assume that a field labeled “API” has identical length or semantics in every dataset. The FracFocus API number explainer provides useful background, but the regulator responsible for the well remains the authoritative source for its records. For federal land context, use the BLM oil and gas program and the relevant state office resources.
Preserve the identifier exactly as displayed, including leading zeros, punctuation, and suffixes. Store any search-normalized representation in a separate field with a documented transformation rule. A convenient numeric data type can silently drop leading zeros and create a false match.
Model relationships, not replacements
A crosswalk should be append-only. Each observed identifier gets a source key, observation date, and locator. Relationships between observations then receive their own records. Useful relationship labels include same identifier in alternate format, predecessor, successor, parent bore, child completion, sidetrack, recompletion, corrected record, and possible match.
Do not overwrite the old identifier when a portal displays a new one. Historical production files, recorded instruments, invoices, and correspondence may continue to use the former value. Keeping both allows searches in either direction and shows which identifier was current at a particular time.
| Evidence field |
Capture rule |
| identifier as shown |
exact characters and source label |
| well name and number |
exact text, including suffixes |
| object level |
permit, wellbore, completion, facility, or unknown |
| location |
legal description and coordinates as separately sourced values |
| operator |
name and operator number as observed on that record |
| formation or pool |
source terminology, not an analyst’s substitution |
| filing event |
permit, completion, recompletion, transfer, plugging, or correction |
| relationship |
proposed type, evidence, status, reviewer, and date |
This design accommodates one-to-many relationships. A single bore may have several completion records, and a sidetrack may retain some location attributes while receiving another suffix. Forcing every old identifier into one current value hides that structure.
Build an event spine
Organize evidence chronologically: permit application, identifier assignment, drilling or completion filing, operator change, recompletion, sidetrack, correction, status change, and plugging record. Label each date by its source meaning. Filing date, approval date, completion date, effective date, and database observation date are not interchangeable.
Attach source documents to events rather than only to the final crosswalk row. That lets a reviewer see why a relationship was proposed. If a regulator filing explicitly references both identifiers, cite the exact page or field. If the relationship is inferred from several attributes, list those attributes and mark the relationship as proposed until reviewed.
Later data should not rewrite the historical observation. If a portal changes a name or status, capture a new observation with its timestamp. This is especially important when an internal report must be reconstructed as of a prior closing or accounting period.
Use a hierarchy of match evidence
Not all clues deserve equal weight. An explicit regulator record connecting old and new identifiers is stronger than matching names. Exact full identifiers and filing references are generally stronger than a shared lease name. Coordinates and legal locations help, but nearby bores can share a pad. Operator identity can change. Formation and completion suffixes may distinguish records that otherwise look alike.
Establish a written matching protocol approved for the project. It can require an explicit linking document for automatic confirmation and send all inferred matches to review. Record which rule version evaluated each row. That is safer than an opaque confidence score.
Consider two portal results with the same lease name and surface location, one ending in 00 and the other in 01. Do not trim the final digits and merge them. Capture both full values, determine what the suffix represents in that jurisdiction and source, and locate the permit, completion, or correction filing that explains the relationship. Until then, the crosswalk should show a possible relationship, not identity.
Protect downstream systems
Before loading a crosswalk, inventory the systems that consume the identifier: land, production, revenue, regulatory, accounting, GIS, document management, and reporting. Identify which field is the local primary key and which fields can hold aliases. Never replace a production key merely to improve search results.
Use effective-dated aliases where the system permits them. Preserve source system, valid-from or observed-from date, valid-to date if established, mapping status, approving role, and reason. For systems without alias support, maintain a controlled reference table rather than scattering manual substitutions across reports.
Test both false merges and missed joins. Sample records with matching names but different suffixes, matching coordinates but different bores, and changed operator names. Also test searches using the old identifier to confirm that users can still reach the current file. Record load counts, rejects, duplicates, and rollback instructions before production use.
Turn ambiguity into an exception queue
Every unresolved row needs an exception ID, the competing values, affected system or business action, evidence checked, missing evidence, owner, and next review date. Categories might include truncated identifier, conflicting suffix, source-format uncertainty, duplicate internal key, unlinked recompletion, coordinate-only match, or inaccessible filing.
State bounded questions. “Fix well number” is not useful. “Does filing X establish that identifier ending 01 is a completion under the bore represented by identifier ending 00 for document retrieval only?” tells the reviewer exactly what relationship and use are being considered.
Unsuccessful searches should remain visible. Record the official system, search value, variants, filters, access time, and returned result. A zero-result search proves only what that query returned at that time.
Verify before release
A second reviewer should reopen the direct sources for every high-impact match, compare identifiers character by character, and confirm the object level on both sides. Reproduce transformation rules, inspect one-to-many relationships, and verify that proposed mappings cannot flow downstream as approved. Reconcile the source population to the crosswalk and the crosswalk to the target load.
The final packet should contain the source dictionary, event history, relationship table, exception register, approval log, and load reconciliation. It should also state its boundary: the crosswalk supports administrative retrieval and controlled mapping. It is not an engineering determination, a regulatory filing, or a conclusion about well identity based solely on proximity.
Teams that need help organizing well files and evidence-backed system mappings can explore Landman Business services or Book a free consultation with the jurisdictions, source systems, and output requirements.
The central discipline is simple: preserve every source value, explain every transformation, and make every relationship carry evidence and status. That keeps a useful search aid from becoming an undocumented master-data decision.
