Established
Fiber can provide continuous depth-resolved sensing
DAS, DTS, and DSS are established sensing families. Performance depends on fiber type, installation, coupling, interrogator settings, and the signal being measured.
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Research proposal · fact-checked August 2026
From invisible liabilities to subsurface sentinels
Selected old wells may be useful monitoring locations. That is a credible hypothesis—not yet a Canadian monitoring network.
The proposition
A cable can listen along an entire well
An interrogator sends laser pulses through optical fiber and analyzes the returning light. Depending on the system and cable, the fiber can provide distributed acoustic sensing (DAS), temperature sensing (DTS), or strain sensing (DSS) at many points along its length. With a seismic source, DAS can also act as the receiver array for a vertical seismic profile.
Government-funded field work has demonstrated downhole DAS and DTS for subsurface imaging and leakage-related monitoring, including fiber deployed on tubing in a pre-existing well. Those demonstrations support a pilot. They do not establish that Canada's orphan wells contain accessible fiber, that surviving cable is usable, or that retrofit is safe and economic at any particular site.
Evidence ledger
What is known—and what is not
Established
DAS-VSP can image the subsurface
A seismic source is required. Passive DAS may hear natural or operational events, but it is not automatically a subsurface image.
Established—with limits
Thermal and acoustic anomalies can help locate flow
DTS and DAS can indicate changes consistent with fluid movement or a leak. Interpretation normally needs baseline data, modelling, and corroboration.
Not established
Canada has a usable orphan-well fiber inventory
No public national dataset located in this review records fiber presence, type, depth, condition, accessibility, or ownership for orphan wells.
Site-specific
An old well can be retrofitted
Fiber can be tubing-deployed or installed during intervention, but well access, barriers, casing condition, pressure, cable coupling, regulatory approval, and worker safety control feasibility.
Requires separate instruments
Fiber identifies the pollutant
Standard DAS, DTS, and DSS do not directly report methane, H₂S, BTEX, or radon concentration. Chemical sensors, flux measurements, sampling, or laboratory analysis are required.
Alberta source audit
The first map result is a documented blank
Public regulator and OWA datasets can establish lifecycle, location, OWA management, casing failures, and reported vent flow or gas migration. None of the reviewed bulk datasets contains a field for installed fiber. Fiber must therefore remain unknownfor every well until a completion, intervention, or equipment record establishes otherwise.
21,223unique well licences in the OWA full inventory snapshot dated August 4, 2026. The inventory includes AER-designated orphan assets and WIPA assets, so this is an OWA-management count—not a current orphan-well total.
11,324unique licences with one or more records in the AER Well Casing Failures Report retrieved August 16, 2026. There are 12,809 report rows, including repeat reports for the same licence; 620 rows have no reported resolution date.430 of those licences also appear in the OWA-management snapshot. This is a records overlap, not proof that every listed failure remains open or caused a surface release.
33,571unique parseable well licences in 40,732 rows from the AER Vent Flow and Gas Migration Report retrieved August 21, 2026. Of these, 33,560 match the current ST37-derived map and 1,886 occur in the OWA-management snapshot.11,620 input rows have no resolution date; 29,112 have one. A resolution date is a recorded field—not independent proof that physical flow stopped.
| Public source | Supports | Does not establish |
|---|---|---|
| AER ST37 | Location, depth, lifecycle mode, licence and operator codes | Orphan designation, fiber, leakage |
| OWA site inventory | Assets managed by OWA; project and component records | Fiber; reliable per-row orphan/WIPA split |
| AER casing-failure report | 12,809 reports across 11,324 licences; failure type and resolution fields | No failure; fiber; chemical concentration |
| AER vent-flow / gas-migration report | 40,732 reports; type, classification, flow and recorded resolution | No report; current physical flow; fiber; complete emission history |
| Directive 013 inactive list | Inactivity and regulator risk categories | Orphan designation; fiber; measured emissions |
Download the evidence schemaDownload the evidence snapshotMachine-readable · source and coverage notes included
The useful question
Where could a pilot reduce uncertainty?
Start with records, not hardware. Regulators, the Orphan Well Association, former operators, service companies, and completion records may identify wells with permanent fiber or optical gauges. Each candidate then needs a records review and a safe-access assessment.
Rank candidates by public value: known or suspected leakage, proximity to homes and water, integrity history, geology, clustering with other wells, surface power and communications, and whether the well will remain physically accessible. Indigenous rights holders and affected landowners must be involved in governance and siting—not treated as downstream recipients of data.
A sentinel well should only represent nearby wells where geology and pathways justify that inference. Fiber in one borehole does not turn it into a universal detector for an oilfield.
Minimum viable pilot
Prove the chain from anomaly to action
- 01
Inventory
Search completion and abandonment records; publish fiber status as yes, no, or unknown with provenance.
- 02
Baseline
Collect methane flux or concentration, pressure where available, temperature, acoustic data, and local environmental context.
- 03
Controlled test
Compare permanent fiber, temporary deployment, and conventional instruments at a small set of safe, accessible wells.
- 04
Verify
Define detection thresholds in advance, investigate false alarms, and verify suspected events with independent chemical or physical measurements.
Success is not “the fiber produced data.” Success is a repeatable, independently verified detection or integrity measurement that changes a remediation or monitoring decision at an acceptable cost.
A monitoring-potential layer
What OilDebt.ca can responsibly map now
The first product should expose uncertainty rather than imply sensors exist. Candidate fields include fiber status and source record, accessibility, well depth and geometry, casing and abandonment history, known methane or H₂S testing, groundwater and community proximity, last inspection, data owner, and a clearly explained priority score.
Confirmed leaking
High-risk · unmonitored
Candidate · needs assessment
Fiber recorded · condition unknown
Instrumented sentinel
Plugged · verification unknown