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Swelling/extraction tests are single-contact phase-behavior experiments to measure the solubility of CO 2 dissolved in crude oil and the amount of hydrocarbon that CO 2 can extract or vaporize from crude oil. The tests are commonly conducted in a visual PVT cell with a large sample size (40-100cc). In this paper, an easy operated apparatus capable of determining phase behavior with a significantly smaller sample size (3 to 14 cc) is described. The apparatus consists of a high-pressure view cell, high-pressure and precision syringe pump filled with CO 2 , a water bath, and accessories to measure the temperature and pressure. The device is capable of determining vapor-liquid, liquid-liquid and vapor-liquid-liquid equilibrium commonly observed in a high pressure CO 2 enhanced oil recovery process. The solubility of CO 2 in oil, the expansion volume of oil due to the dissolution of CO 2 as well as the phase transition during the test were quantified with excellent reproducibility. The molar volume of oil saturated with CO 2 correlated linearly with the mole fraction of dissolved CO 2 suggesting ideal mixing in the liquid phase. The phase behavior between CO 2 and crude oil samples with different composition, temperature and pressure is discussed.

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Polyacrylamides are often used in water-based hydraulic fracturing for natural gas and oil production. However, residual polymer remaining in the fractured rock can limit production. A novel approach for degrading partially hydrolyzed polyacrylamide (HPAM) was investigated using hydrogen peroxide and horseradish peroxidase (HRP). This sustainable HRP/H 2 O 2 system degraded the polymer in solution, reducing its viscosity in both pure water and brine solutions. Molecular weight measurements confirmed that the viscosity reduction was due to a significant degradation of the polymer backbone and not primarily by other mechanisms such as amide hydrolysis or rearrangement, and so forth. The reduction in viscosity and molecular weight was first order with respect to H 2 O 2 concentration. The kinetics of viscosity reduction and molecular weight are closely correlated which would allow the quicker and simpler viscosity method to help engineer future processes.