Methods and systems for performing pressure-volume-temperature testing on fluids include: a portable environmental control chamber 14, a first pressure vessel 12A disposed inside the portable environmental control chamber, a second pressure vessel 12B disposed inside the portable environmental control chamber, the second pressure vessel in hydraulic communication with the first pressure vessel, a viscometer 18 configured to measure the viscosity of fluids flowing between the first pressure vessel and the second pressure vessel, and an optics system 22 configured to measure optical properties of fluids flowing between the first pressure vessel and the second pressure vessel.
