APIs › Petroleum Engineering Calculators › Gas Z-Factor

Gas Z-Factor

Gas compressibility factor by the Dranchuk–Abou-Kassem correlation with Sutton pseudo-critical properties and optional sour-gas correction, reporting convergence and whether inputs are inside the correlation's validated range.

POST /v1/petroleum/gas-z-factor $0.03 per call

Specification

Endpoint

POST /v1/petroleum/gas-z-factor

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/gas-z-factor" \
  -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.

{
  "z_factor": 0.864,
  "converged": true,
  "iterations": 5,
  "reduced_properties": {
    "pseudo_reduced_pressure": 4.6438,
    "pseudo_reduced_temperature": 1.6679,
    "reduced_density": 0.8701
  },
  "pseudo_critical": {
    "pressure_psia": 646.02,
    "temperature_r": 383.53,
    "source": "Sutton (1985) from gas specific gravity",
    "sour_correction_applied": true,
    "wichert_aziz_epsilon_r": 6.173
  },
  "gas_density_lbm_ft3": 10.9881,
  "correlation": "Dranchuk & Abou-Kassem (1975), Newton-Raphson solution",
  "references": [
    "Dranchuk & Abou-Kassem (1975), J. Cdn. Pet. Tech. 14(3)",
    "Sutton (1985), SPE 14265",
    "Wichert & Aziz (1972), Hydrocarbon Processing 51(5)"
  ],
  "validity": {
    "validated_range": "1.0 < T_pr < 3.0, 0.2 ≤ P_pr ≤ 30",
    "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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