# Petroleum PVT Calculator Guide

> A petroleum PVT calculator guide for gas formation volume factor, oil formation volume factor, real-gas density, API gravity, and reservoir-to-surface volume conversion checks.

## Key Takeaways
- Formation volume factors convert between reservoir-condition and standard-condition volumes.
- Gas formation volume factor depends on pressure, temperature, and z-factor; z-factor quality controls result quality.
- Oil formation volume factor is usually greater than 1 because dissolved gas leaves solution as pressure drops to surface conditions.

## Workflow
1. Confirm whether pressure and temperature inputs must be absolute before entering PVT values.
2. Use Bg calculators when converting gas surface volumes to reservoir volumes or vice versa.
3. Use Bo calculators when reservoir oil volume and stock-tank oil volume need to be reconciled.
4. Treat quick correlations as screening tools unless they have been calibrated against fluid-sample or equation-of-state work.

## Calculators
- [Gas formation volume factor calculator](/calculators/gas-formation-volume-factor)
- [Oil formation volume factor calculator](/calculators/standing-oil-formation-volume-factor)
- [Real gas density calculator](/calculators/real-gas-density)
- [API gravity calculator](/calculators/api-gravity)

## Formula References
- [Gas Formation Volume Factor calculator](/calculators/gas-formation-volume-factor)
- [Gas Formation Volume Factor formula and calculator](/calculators/gas-formation-volume-factor#formula-reference)
- [Standing Oil Formation Volume Factor calculator](/calculators/standing-oil-formation-volume-factor)
- [Standing Oil Formation Volume Factor formula and calculator](/calculators/standing-oil-formation-volume-factor#formula-reference)
- [Real Gas Density calculator](/calculators/real-gas-density)
- [Real Gas Density formula and calculator](/calculators/real-gas-density#formula-reference)
- [API Gravity calculator](/calculators/api-gravity)
- [API Gravity formula and calculator](/calculators/api-gravity#formula-reference)

## Verified Sources
- [Gas formation volume factor](https://glossary.slb.com/Terms/g/gas_formation_volume_factor.aspx) - SLB Energy Glossary
- [Oil formation volume factor](https://glossary.slb.com/en/Terms/o/oil_formation_volume_factor.aspx) - SLB Energy Glossary

Important use note: calculator outputs support engineering checks, study, and review. They do not replace professional engineering judgment, company procedures, regulatory requirements, or source standards.