APIs › Petroleum Engineering Calculators › Oil Viscosity Correlation

Oil Viscosity Correlation

Dead, saturated and undersaturated oil viscosity by Beggs–Robinson with Vasquez–Beggs above bubble point, with valid ranges and extrapolation warnings.

POST /v1/petroleum/oil-viscosity-correlation $0.03 per call

Specification

Endpoint

POST /v1/petroleum/oil-viscosity-correlation

Price

$0.03 per call · tier strategy_intelligence

Payment

x402 on X Layer (chain 196) · settled in USDG or USDT0 · scheme exact

Data source

Published petroleum-engineering correlations, cited per endpoint

Timeout

15 seconds

Max request

64 KB

Version

1.0.0

Calling it

The first call returns a 402 with the payment challenge. Retry with a signed authorisation in the X-PAYMENT header — see the payment guide for the exact shape.

curl -i -X POST "https://api.dana-edu.pp.ua/v1/petroleum/oil-viscosity-correlation" \
  -H "content-type: application/json" \
  -d '{ ... }'

Response

Real output, captured by running this endpoint at build time — not written by hand. Volatile fields such as timestamps are elided. Captured 2026-07-30.

{
  "dead_oil_viscosity_cp": 3.3129,
  "saturated_oil_viscosity_cp": 0.8245,
  "undersaturated_oil_viscosity_cp": 0.9685,
  "reported_viscosity_cp": 0.9685,
  "regime": "undersaturated",
  "intermediate": {
    "beggs_robinson_Z": 2.4255,
    "beggs_robinson_Y": 266.37901,
    "beggs_robinson_X": 0.63477
  },
  "correlations": {
    "dead_oil": "Beggs & Robinson (1975), SPE 5434",
    "saturated": "Beggs & Robinson (1975), SPE 5434",
    "undersaturated": "Vasquez & Beggs (1980), SPE 6719"
  },
  "validity": {
    "validated_range": "16-58 °API, 70-295 °F, Rs 20-2070 scf/STB, p ≤ ~5250 psia",
    "in_range": true,
    "notes": []
  },
  "note": "Screening-level engineering result. It does not replace a commercial simulator, a laboratory PVT measurement, or review by a qualified engineer."
}

Every response is wrapped in the same envelope: data plus warnings, sources, confidence, informational_only and a measured processing_ms. See the envelope reference.

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