You could have downloaded GOWProp 11.06 from our software library for free. This free program was originally developed by NorCraft. The most popular versions among GOWProp users are 11.0 and 8.0. The program lies within Office Tools, more precisely Calculators. The program's installer file is commonly found as Gowprop.exe.
From the developer:
GOWProp is a Physical Properties program that calculates PVT properties of gas, oil, and water - with your choice of calculation methods. Pick from a selection of standard equations for calculating certain properties. More than 12 properties are calculated and the results include a pressure depletion table of the various properties and will plot the output on screen. U.S. and SI Units.
You may want to check out more software, such as iUnit, ESBProgCalc Pro or Pico Diagnostics, which might be similar to GOWProp.