Browsing by Subject "MMP"
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Item Advances in calculation of minimum miscibility pressure(2011-05) Ahmadi Rahmataba, Kaveh; Johns, Russell T.; Bryant, Steven L.; DiCarlo, David; Dindoruk, Birol; Sepehrnoori, KamyMinimum miscibility pressure (MMP) is a key parameter in the design of gas flooding. There are experimental and computational methods to determine MMP. Computational methods are fast and convenient alternatives to otherwise slow and expensive experimental procedures. This research focuses on the computational aspects of MMP estimation. It investigates the shortcomings of the current computational models and offers ways to improve the robustness of MMP estimation. First, we develop a new mixing cell method of estimating MMP that, unlike previous "mixing cell" methods, uses a variable number of cells and is independent of gas-oil ratio, volume of the cells, excess oil volumes, and the amount of gas injected. The new method relies entirely on robust P-T flash calculations using any cubic equation-of-state (EOS). We show that mixing cell MMPs are comparable with those of other analytical and experimental methods, and that our mixing cell method finds all the key tie lines predicted by MOC; however, the method proved to be more robust and reliable than current analytical methods. Second, we identify a number of problems with analytical methods of MMP estimation, and demonstrate them using real oil characterization examples. We show that the current MOC results, which assume that shocks exist from one key tie line to the next may not be reliable and may lead to large errors in MMP estimation. In such cases, the key tie lines determined using the MOC method do not control miscibility, likely as a result of the onset of L₁-L₂-V behavior. We explain the problem with a simplified pseudo-ternary model and offer a procedure for determining when an error exists and for improving the results. Finally, we present a simple mathematical model for predicting the MMP of contaminated gas. Injection-gas compositions often vary during the life of a gasflood because of reinjection and mixing of fluids in situ. Determining the MMP by slim-tube or other methods for each possible variation in the gas-mixture composition is impractical. Our method gives an easy and accurate way to determine impure CO₂ MMPs for variable field solvent compositions on the basis of just a few MMPs. Alternatively, the approach could be used to estimate the enrichment level required to lower the MMP to a desired pressure.Item Extracellular matrix mechanics regulate cell signaling and migratory potential in cancer(2012-05) Srivastava, Jaya, active 2012; Ellington, Andrew D.; Zaman, Muhammad H.The objective of the presented research is to examine the relationship between the cellular microenvironment and biochemical response of metastatic cells. Clinically recognized as a trait of cancer progression, the cellular microenvironment can have variable and distinct mechanical properties that are processed via cellular mechanosensing, resulting in a cellular biochemical response. A range of studies investigating the interactions between the cellular micromechanical environment and the cell's molecular response during disease progression have been made, yet remain absent of quantitative characterization of many of these coordinated responses. The fundamental inquiry that drives the following research attempts to elucidate how a cell perceives the physical microenvironment and converts that signal to a biochemical response. With the goal of providing insight to such responses, the presented research seeks to elucidate the following questions: (1) What are the integrated effects of ECM stiffness, ECM architecture, and breast cancer cell metastatic potential on cell migration? (2) How does endogenous tissue transglutaminase (tTG) cross-linking of the ECM scaffold effect ECM mechanical properties? (3) How does the architecture and stiffness of the extracellular matrix (ECM) effect the systems-level cellular migration and signaling response? (4) What are the integrated effects of ECM architecture and the targeted knockdown of integrin [beta]1 and MT1-MMP on cellular metastatic potential? The presented research utilizes an interdisciplinary approach, integrating experimental mechanics, biochemical analysis, cellular biology techniques, covalent chemistry, and various microscopy techniques, to investigate these events. In short, cancerous cells are cultured atop or within synthetic collagen type I ECMs of varying mechanical stiffness and structure. These cells are subsequently analyzed by molecular analysis and immunoassays, including quantitative PCR, Western blotting, and gelatin zymography, to acquire measures of the cellular response to perturbations of micromechanical environment. Time-lapse microscopy experiments and subsequent image analyses enable observations of cellular migratory potential through synthetic ECMs. Results indicate that cooperative synergy between ECM properties, cell-matrix adhesion, and pericellular proteolysis drive cell migratory potential of highly invasive tumorigenic cell populations. Collectively, these findings contribute to the cancer biology and mechanobiology fields by systematically extending current insights of matrix mechanics, cellular signaling, and cellular migratory potential in cancer.Item Improved Fluid Characterization for Miscible Gas Floods(2004-12) Egwuenu, Azubuike Michael; Johns, Russell T.Injection of gases into a reservoir for enhanced oil recovery results in complex fluid phase behavior that cannot be modeled by black oil simulators. This interaction of flow and phase behavior is best captured by fully compositional simulators. A drawback of fully compositional simulators is that they require accurate reservoir fluid characterizations by equations of state (EOS) to capture the phase interactions in miscible gas floods. Another disadvantage is that EOS are computationally intensive. An EOS is typically tuned to standard PVT data, which may include multicontact experiments and swelling tests. The standard method of tuning, however, does not incorporate important displacement parameters such as the minimum miscibility pressure or enrichment (MMP or MME) or the likely compositions that result in a reservoir from condensing-vaporizing displacements.