Measurements and Modeling of Phase Behavior, Density, and Viscosity of Oil + Carbon Dioxide: Squalane + CO₂ at Temperatures (313 to 363) K and Pressures up to 77 MPa

New measurements of compressed liquid density, viscosity, and bubble pressures of mixtures of carbon dioxide and squalane are reported for CO₂ mole fractions x = (0.199, 0.299, and 0.519) at temperatures (313, 338, and 363) K, and pressures from bubble points up to about 77 MPa. Density was measured using a "bare-bone" vibrating U-tube driven and scanned in the frequency domain with a lock-in amplifier where the resonance peak is acquired in complex form and density is determined with an expanded uncertainty of U(ρ) = 0.003ρ. Viscosity was measured with a custom-made capillary viscometer made of a stainless steel 1/8 in. tube with a length of about 3 m and an internal diameter of about 0.4 mm, where the pressure drop is measured while the fluid mixture is swept through at a constant flow rate. Bubble pressures were determined from the discontinuity of p-V plots recorded during a series of isothermal constant composition expansion processes (CCE) in a variable volume pressure cell. The data reported in previous literature were modeled using Tait-like equations for each single composition, but in this work, equations of state and the Expanded Fluid Theory were used to model density and viscosity, respectively, over the whole surface of pTx reported in the literature. For density, Redlich-Kwong-Soave EOS gives best predictions with an average absolute deviation of 1.1%, where the deviations are high near the bubble points but also increase in a systematic manner with increasing CO₂ mole fraction. Best predictions for bubble pressures were given by Peng-Robinson EOS. The excess molar volume is also calculated as a function of pressure and temperature. The Expanded Fluid viscosity theory reproduced all experimental measurements in this work and in the literature, with an average absolute deviation of 6.8%. Viscosity reduction effect of CO₂ is also estimated and presented as a percentage of pure oil viscosity (η/η_w=0) as a function of CO₂ mass fraction w.