Date of Award
Doctor of Philosophy in Chemical Engineering
Given the complexity of shale gas at high pressures, researchers aim to characterize the thermodynamic properties of confined fluids using a mixture of experimental, modeling, and simulation techniques. In this work we frequently use the predictive capabilities of simulation to couple the property results to models. The overall results are then compared to experimental data for verification purposes.
We employ a Monte Carlo simulation technique to ensure that a simple linear mixing rule for internal energies of departure holds thereby allowing pure component data to extend to mixtures. The results are coupled to the Gibbs-Helmholtz Constrained equation of state allowing for bulk-scale bubble point reduction predictions. In addition, the sensitivity of the results is determined.
Adsorption of n-alkanes at high pressure conditions are studied as a function of carbon chain length, temperature, and pore throat size (14.2 Å to 19.88 Å) to give an overall picture of shale gas behavior at reservoir conditions. A simple model is shown to provide a reasonable estimate of the isotherms at high pressures up to 500 bar and a temperature range of 300 K to 550 K. Under the assumption of ideal site-site interactions, mixtures are predicted for methane/ethane and methane/ethane/propane systems and compared to work in the literature.
An important aspect of this work is the verification to experimental data; we expand on recent work by characterizing the experimental to simulation data in a robust manner. Quantitative agreement is achieved when estimating the surface area and void volume of the porous material.
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Thomas, Edward Alan, "Understanding Confined Fluids in Shale Gas Systems" (2018). Open Access Dissertations. Paper 744.