Architecture Proof · Claim #3 · Methane MRV
A source-level methane inventory reconciled against a site-level measurement per ISO 25624-1 — verified on a live OSDU platform, then formally restated after the standard's own worked anomaly: an unlit flare caught as a super-emitter.
A five-source bottom-up inventory (156,300 kg CH₄) reconciled within 8.5% of a drone-flux top-down measurement and was verified Gold-Standard. A subsequent re-survey caught an unlit flare at 600 kg/h; instantaneous reconciliation failed at 97%, the plan was suspended, the 72-hour episode was annualized (+27% — above the 5% materiality threshold), and the inventory was formally restated, re-reconciling at 6.8%. Every step ran against real OSDU services with immutable versioning.
Lifecycle
ISO 25624-1 §5.1 requires a formal Monitoring Plan where verification is needed. Here it is the certifiable wrapper; each transition is a distinct immutable OSDU version.
Bottom-up · ISO Formula (1)
Five representative sources from the ISO Clause 6 taxonomy, each quantified by a method and OGMP level chosen by materiality (§8): material sources at L4, the 2.8% fugitives legitimately on a generic factor at L3.
| Source | ISO category | Method | Level | kg CH₄ / yr |
|---|---|---|---|---|
| Flare stack (98% DRE) | flaring | direct measurement | L4 | 96,000 |
| Intermittent pneumatics ×40 | ventingPneumatic | emission factor | L4 | 17,520 |
| Compressor rod-packing ×2 | ventingCompressorReciprocating | direct measurement | L4 | 19,200 |
| Engine slip ×3 (CEMS) | incompleteCombustion | direct measurement | L4 | 19,200 |
| Leaking connectors ×25 | fugitive | generic EF | L3 | 4,380 |
| Bottom-up total · 4,376 t CO₂e @ GWP100 = 28 | 156,300 | |||
Reconciliation gate · ISO Clause 11
The gate is the SysML methane constraint block, each clause traced to the standard. Verification was issued only because all six held.
| Constraint | Evidence | At verify | On anomaly |
|---|---|---|---|
| SiteLevelReconciliation (11) | |BU−TD|/TD: 8.5% ≤ 20% → 97.1% instantaneous | PASS | FAIL |
| GoldStandardCoverage (OGMP 2.0) | L4/L5 coverage 97.2% ≥ 95% | PASS | PASS |
| MaterialityRigor (8, F.25) | material sources at L4+; finding +27% > 5% | PASS | RESTATE |
| MethaneLeakDetectionThreshold | 19.5 kg/h ≥ LoQ 0.5 kg/h | PASS | PASS |
| EmissionRateAccuracy (9) | flare 3.3% ≤ 10% (L4) | PASS | PASS |
| ReportingFrequency (EU 2024/1787) | 4 quarterly LDAR surveys | PASS | PASS |
Anomaly & restatement · ISO 11.3 · 12.3
ISO 25624-1 cites an unlit flare releasing raw gas as the archetypal reconciliation discrepancy. The cascade follows its Figure 1 workflow to a formal restatement.
Super-emitter
Unlit flare (DRE = 0): 600 kg/h raw gas, > 100 kg/h threshold
Re-reconcile · 11.3.1
Instantaneous 17.8 vs 607.5 kg/h — 97% divergence, class C
Plan
verified → suspended; attestation suspended
Annualize · 6.3.4.3
72 h from last credible lit data: +42,336 kg CH₄
Restatement · 12.3
+27% of inventory > 5% materiality → formal restatement
Re-reconciled
198,636 vs 213,156 kg/yr — 6.8% ✓ · plan restated · attestation re-issued
Trust layer
A VerifiableCredential (issuer did:web:dveracity.com, Ed25519 proof) is bound to the Monitoring Plan's SHA256 and carries the ISO expanded uncertainty as its confidence basis. It tracked the lifecycle exactly: issued → suspended → re-issued on the restated hash — three immutable versions.
OFP data domains · canonical model
The methane kinds above are dVeracity's SysML view. To make claim #3 an OFP-conformant emissions data flow, the proof was re-expressed across five OFP data domains on the canonical kinds — 28 additional kinds registered through the same OFP→OSDU pipeline as the original load, 240 records forming one connected graph, and the Monitoring Plan versioned once more to point at it.
| OFP domain | What carries the methane story | Records | Kinds |
|---|---|---|---|
| Organizational Structure / Boundary | operator with an LEI (OrganizationExternalIdentifier), operational-control boundary (OrganizationControl), verifier organization and its lead verifier | 11 | 9 |
| Facility Structure | site → two process units (FacilityStructure), location, one EquipmentInstallation per methane source, compliance requirements for EU 2024/1787 and OGMP 2.0 | 31 | 13 |
| Recording | ISO Formula (1) as an EmissionCalculationFormula with EF / N / t components; per source a model, three arguments, three argument values, an EmissionStatement and its uncertainty; the top-down and aggregate statements | 135 | 26 |
| Reporting | the OGMP 2.0 annual EmissionReport, period, reporting boundary, per-standard references (ISO, OGMP, EU), seven statements-per-report with facility allocations, a reasonable-assurance ReportingAssurance | 21 | 8 |
| Data Verification | the six gate constraints as DataQualityRules in one DataQualityRuleSet; every gate run as DataQuality assessments evaluated against the methane records — verify 100%, anomaly 83.3% (SiteLevelReconciliation = 0), restated 100%; the dVeracity attestation as an OFP VerifiableCredential | 42 | 11 |
Resolved by foreign key through the OSDU Search API, 18 of 18 hops.
Chain A · recording
Report ⋈ flare statement → model → ISO Formula (1) → Standard ISO 25624-1
Chain A · structure
statement → activity → process unit → site → operator → LEI · operational control
Chain B · assurance
ReportingAssurance → verifier organization → lead verifier (ISO 14065)
Chain B · verification
rule set → the one DataQuality with score 0 → SiteLevelReconciliation → the evaluated methane record
Evidence ledger · portable
Every record and version history was exported from OSDU to JSON committed in this repository — 342 record bodies, 515 version bodies and all 158 schemas — so the proof outlives the environment. The console beside this report replays that bundle.