Gulf decommissioning glossary
The vocabulary of Gulf of Mexico decommissioning, defined in plain English — with the commercial meaning a regulator's glossary leaves out.
Wells
- APM also: Application for Permit to Modify, eWell APM
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Application for Permit to Modify: the permit an operator files to change a well’s configuration, including abandonment work. BSEE publishes these through its eWell system.
Why it mattersThe APM dataset is where well decommissioning becomes visible first — usually well before any contract is signed.
Read more: How BSEE filings reveal work before execution How to read the Gulf decommissioning sales window
- EOR also: end-of-operations report
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End-of-Operations Report: the filing an operator submits after finishing work on a well. For abandonment work it is the record that the plugging is complete.
Why it mattersAn EOR confirms work finished. A missing EOR does not prove open work — the filing may simply be late. GOMDecom therefore reports "remaining observable scope", never "unawarded".
Read more: How BSEE filings reveal work before execution 1,813 open wells—and the sales window behind them
- P&A also: plug and abandonment, permanent abandonment
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Plug and abandonment: the permanent sealing of a well with cement barriers so it cannot flow, followed by cutting and removing the wellhead. It is the step that discharges the well part of a decommissioning obligation.
Why it mattersA filed P&A permit with no work commencement on record is the clearest early signal that well scope is live but not yet executed.
- Rigless and riserless P&A also: rigless, riserless abandonment
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Abandonment methods that avoid a full drilling rig. Rigless work uses vessel-deployed wireline or coiled tubing; riserless work operates without a marine riser back to surface.
Why it mattersMethod choice drives who can bid. Rigless and riserless scopes open shallow-water campaigns to vessel operators rather than rig contractors.
- TA well also: temporary abandonment, temporarily abandoned
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A well sealed with temporary barriers and left recoverable rather than permanently plugged. Temporary abandonment is approved for a limited period and is meant to be a holding state, not an end state.
Why it mattersTA wells are future P&A scope. A lease carrying decades-old TA wells is a backlog waiting for a trigger, not completed work.
Read more: What temporarily abandoned wells mean for future P&A 1,813 open wells—and the sales window behind them
Structures & pipelines
- Pipeline decommissioning also: out of service, flushed and abandoned
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Taking a pipeline segment permanently out of service, typically by flushing, filling and sealing the ends, and either leaving it buried in place or removing it.
Why it mattersPipeline scope is routinely overlooked because it sits in a separate dataset from wells and platforms, yet it attaches to the same campaigns.
Read more: The 1,304-segment pipeline tail behind Gulf campaigns
- Rigs-to-Reefs
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A programme that lets a retired offshore structure stay in place as a permitted artificial reef instead of being brought ashore, usually by toppling it in place or towing it to an approved reef site.
Why it mattersReefing changes the scope rather than removing it. The heavy lift and tow still happen; the onshore disposal does not.
- Site clearance
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Proving the seafloor is clear of obstructions after a structure comes out. Verification is done by trawling or sonar survey over the site, and the result is reported to the regulator.
Why it mattersSite clearance is the last billable scope in a campaign and is frequently a separate award from the removal itself.
Read more: A platform removal, application to clearance
- Structure removal application also: removal permit
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The application an operator files for approval to remove a platform or caisson. It sets out the removal method, the severance approach and the planned schedule.
Why it mattersAn approved application with no removal date on record is the structure equivalent of a filed, unstarted P&A permit.
Read more: A platform removal, application to clearance Where 806 standing Gulf structures sit in the sales window
Regulatory
- BSEE / BOEM / MMA
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BSEE regulated offshore safety and environmental enforcement; BOEM managed leasing. Secretary’s Order 3451 merged the two in July 2026 into the Mineral Management Agency (MMA). Published datasets still carry the legacy naming.
Why it mattersBoth names remain in circulation, and historical filings keep the old ones. Cite both when referencing a record.
- Decommissioning deadline
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The period an operator has to complete decommissioning after a lease terminates or a facility stops being useful. The standard Gulf expectation is one year from lease termination, though case-specific schedules are granted.
Why it mattersA passed deadline with scope still standing is the strongest pursuit signal available — but always treat the date as standard rather than fixed.
Read more: What the Gulf's overdue backlog means for contractors
- Financial assurance also: supplemental bonding
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The bonds, letters of credit or other security an operator must post so the government is not left funding decommissioning if the operator fails. Supplemental assurance is demanded above the base bond when exposure warrants it.
Why it mattersAssurance levels shape who can afford to hold ageing assets, and a rollback changes which operators keep them rather than sell or retire them.
- Idle Iron
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BSEE’s policy requiring operators to decommission wells and platforms that are no longer useful for operations, set out in NTL No. 2018-G03, effective 11 December 2018.
Why it mattersIdle Iron is the clock that turns a dormant lease into an obligation with a date attached. It is the single most useful "why now" signal in the public record.
Read more: How BSEE's idle iron clock forces decommissioning
- OCS also: Outer Continental Shelf
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Outer Continental Shelf: the submerged federal lands beyond state waters where offshore leasing is administered by the federal government rather than a state.
Cost & liability
- ARO also: asset retirement obligation
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Asset Retirement Obligation: the discounted liability a company carries on its balance sheet for retiring its assets. Public operators disclose it in their financial statements.
Why it mattersARO disclosures are an independent cross-check on the regulatory estimate, and they reveal which operators are funding retirement rather than deferring it.
- Decommissioning cost exposure
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The regulatory estimate of what retiring a facility will cost. It is a liability measure used for assurance and accounting, not a price anyone has agreed to pay.
Why it mattersTreat exposure as a sizing signal for how much work exists, never as the value of a contract you could win.
Read more: How BSEE's P50/P70/P90 cost estimates work
- Decommissioning vehicle
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An entity that exists to hold and retire decommissioning liability rather than to produce hydrocarbons. It typically takes on ageing assets with a funding arrangement attached.
Why it mattersThese entities file against a lot of scope, so they look like large accounts. Their funding capacity, not their asset count, decides whether work actually proceeds.
Read more: Fieldwood Energy: the bankruptcy case study
- P50, P70, P90 also: cost percentiles
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Percentiles of BSEE’s decommissioning cost-estimate distribution. P90 is a higher, more conservative figure than P50. BOEM adopted P70 as the basis for supplemental financial assurance in 2024.
Why it mattersThe same facility can show wildly different numbers purely from which percentile is quoted. None of them is a tender value or contractor revenue.
Read more: How BSEE's P50/P70/P90 cost estimates work
- Predecessor liability also: joint and several liability
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The rule that former owners of a lease remain responsible for decommissioning obligations that arose while they held it. Liability is joint and several, so the regulator can pursue any former owner.
Why it mattersWhen the current operator cannot fund the work, the counterparty with the money is often a predecessor — a different company to call.
Read more: Where decommissioning work goes after bankruptcy Fieldwood Energy: the bankruptcy case study
Data
- Commercial window
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The stage of a campaign at which a given service is worth pursuing — scout, engage, bid, execute or close out. It is distinct from the regulatory stage, which tracks paperwork.
Why it mattersRegulatory stage and commercial timing move independently. A permit approved years ago can still be a live window if the work never started.
Read more: How to read the Gulf decommissioning sales window 1,813 open wells—and the sales window behind them
- Lease assignment
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The approved transfer of a lease interest from one company to another. BSEE publishes assignments, which together reconstruct a lease’s ownership history.
Why it mattersAn assignment often precedes a decommissioning push, and it tells you which predecessors remain exposed.
Read more: Where decommissioning work goes after bankruptcy How BSEE filings reveal work before execution
- Remaining observable scope
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The wells, structures and pipeline segments on a lease that the public record does not show as finished. It is what can be observed, not a confirmed inventory of available work.
Why it mattersThis is the honest version of "opportunity size". It separates what the data shows from what a contractor might win.
Read more: The operators behind $2.53bn of remaining P50 scope How BSEE filings reveal work before execution
See the terms applied to live campaigns.
Every one of these appears in a GOMDecom opportunity brief, against real leases and real filing dates, with the source record behind each figure.