Methodology & Sources
Last updated 12 October 2026
petral aggregates free and public market data. The hard part is not the charts but the data: sourcing it, reconciling sources that disagree, and being honest when a feed is late, missing or only an approximation. This page explains the rules every panel follows.
Provenance on every series
Each chart and table carries a provenance badge. It names the source, the time the data refers to, when petral last fetched it, and how it was retrieved:
| MODE | MEANING |
|---|---|
| LIVE | Fetched from the source within that source's own refresh window. Weekly and monthly data stay LIVE until the next scheduled release. |
| SAMPLE | The source could not be reached, so a clearly badged sample is shown to keep the layout usable. A SAMPLE number is never real data. |
And how reliable the number is:
| RELIABILITY | MEANING |
|---|---|
| settlement | An exchange settlement price. |
| official | Published by a government agency or the data's owner (EIA, CFTC, OPEC). |
| proxy | A stand-in for a series that is not freely available, with a note saying what it approximates. |
| estimate | Derived or modelled, with the method stated. |
A number built from several inputs inherits the weakest of them: a spread between a live price and a sample is a sample, and a ratio involving a proxy is a proxy.
Main sources
- Prices and futures curves: delayed exchange quotes (CME, ICE) via Yahoo Finance. Intraday prices are delayed, typically by 10 to 20 minutes.
- Other benchmarks: exchange settlements for ICE gasoil (through CME's look-alike), Dubai swaps (CME), Oman (Gulf Mercantile Exchange) and Shanghai crude (INE), the last converted to dollars at the day's USD/CNY close.
- Inventories, production and balances: US Energy Information Administration (Weekly Petroleum Status Report, Short-Term Energy Outlook, natural gas storage), JODI-Oil, Canada Energy Regulator and the Government of Alberta.
- Positioning: CFTC and ICE Commitments of Traders.
- Macro and rates: FRED (Federal Reserve Bank of St. Louis) and market data.
- Shipping and chokepoints: IMF PortWatch daily transits and listed tanker equities. Freight rate assessments are not freely available, so freight panels use labelled proxies.
- Weather: NOAA National Hurricane Center and Climate Prediction Center, and GDACS.
- News: public RSS feeds. Headlines are shown with their publisher and link to the original.
- OPEC Reference Basket: as published by OPEC.
The status page lists every feed with its current mode and last successful fetch.
What petral does not do
- It does not forecast. Analytics are descriptive: levels, spreads, z-scores, seasonal ranges, curve shape.
- It does not fill gaps. A country that did not report is shown as not reported, not as zero.
- It does not mix contract months. Spreads between two continuous front months are only compared on days when both refer to the same delivery month, and a change across a contract roll is not shown as a price move.
The Library
The Crude Atlas is curated reference data, reviewed by hand. Assays are published producer assays, kept with their own assay and sample dates; the review date records when petral last verified the entry, not when the crude was sampled. A commercial assay describes a representative stream and can differ from an individual cargo certificate.
- Sweet means total sulfur below 0.5 wt%. A grade whose published range crosses that line is classed separately rather than assigned to either side.
- A quality published only as a range has no invented midpoint: it sorts after point values and is not plotted on the quality map.
- Fields link to the assay of the stream they feed where one exists. No standalone reservoir assay is implied.
- Export grades the Atlas holds no assay for show typical published API and sulfur, marked as typical. Individual cargoes vary.
- “Priced off” is the marker a grade's formula or official selling price is set against, not a quote. No grade differentials are shown: they are assessed by price reporting agencies and petral has no free source for them.
- Reserve and output figures carry their own confidence (reported, estimate or rough estimate) and source.
Corrections
If a number looks wrong, it may be. Write to the address on the About page with the panel and the date, and it will be checked against the source.