# Dranchuk correlation

From wiki.pengtools.com

## Contents

## Dranchuk gas compressibility factor correlation

**Dranchuk correlation** is the fitting equation of the classic **Standing and Katz** ^{[1]} gas compressibility factor correlation.

## Math & Physics

^{[2]}

where:

A1 = 0.3265

A2 = –1.0700

A3 = –0.5339

A4 = 0.01569

A5 = –0.05165

A6 = 0.5475

A7 = –0.7361

A8 = 0.1844

A9 = 0.1056

A10 = 0.6134

A11 = 0.7210

## Discussion

Why the **Dranchuk correlation**?

It's classics!— www.pengtools.com

## Workflow

To solve the ** Dranchuk** equation use the iterative secant method.

To find the pseudo critical properties from the gas specific gravity ^{[1]}:

## Application range

^{[2]}

and

^{[2]}

## Nomenclature

- = coefficients
- = reduced density, dimensionless
- = pressure, psia
- = pseudo critical pressure, psia
- = pseudoreduced pressure, dimensionless
- = gas specific gravity, dimensionless
- = temperature, °R
- = pseudo critical temperature, °R
- = pseudoreduced temperature, dimensionless
- = gas compressibility factor, dimensionless

## References

- ↑
^{1.0}^{1.1}Standing, M. B.; Katz, D. L. (December 1942). "Density of Natural Gases".*Transactions of the AIME*. Society of Petroleum Engineers.**146**(SPE-942140-G). - ↑
^{2.0}^{2.1}^{2.2}Dranchuk, P. M.; Abou-Kassem, H. (July 1975). "Calculation of Z Factors For Natural Gases Using Equations of State".*The Journal of Canadian Petroleum*.**14**(PETSOC-75-03-03).