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• Zhang, Kaiqiang

  2016 — Qualitative and Quantitative Technical Criteria for Determining the Minimum Miscibility Pressures from Four Experimental Methods

  Résumé

  In this study, several qualitative and quantitative technical criteria are examined/developed and applied to determine the minimum miscibility pressures (MMPs) of different light crude oilCO2 systems from four experimental methods, i.e., the slim-tube tests, coreflood tests, rising-bubble apparatus (RBA), and vanishing interfacial tension (VIT) technique. First, five slim-tube tests with the live light crude oilCO2 system and five coreflood tests with the dead light crude oilCO2 system are conducted at different injection pressures and the actual reservoir temperature of Tres = 53.0C. It is found that different MMPs can be obtained from the same measured oil recovery factor (ORF) vs. …  Lire la suite

• Zhang, Yizhong

  2016 — Study of Phase Behaviours of Reservoir Fluids with Consideration of Adsorption and Capillary Pressure

  Résumé

  With the development of petroleum science and technology, a systematic understanding of the fundamental phase behaviours of petroleum fluids in bulk volume has been well established. However, the effect of porous media on the phase behaviours of reservoir fluids has always been considered a deep and complicated research topic that has attracted the attention of many scholars worldwide. During the production process, with the change of pressure and temperature, the phase behaviours of reservoir fluids are then changed. Strictly speaking, the process of phase equilibrium occurs in the porous media of formation, and the effect of porous media cannot be …  Lire la suite

• Zhao, Yang

  2016 — Explorations in Periodicity: New Techniques in Audio and Kinematic Data

  Résumé

  Understanding the inherent periodic nature of many signals can help us analyze and obtain more useful information about these signals. In this thesis, a periodicityoriented thinking and analysis approach is presented with signals from three di erent elds. In the rst study, a Waveform-aligned Adaptive Window (WAAW) technique is considered based on the periodic nature of monophonic audio signals. The periodicity information is extracted before the traditional spectral analysis which uses the short-time Fourier transform (STFT). Instead of xed-sized frames, a dynamic size is determined for each frame based on its cycle length. The direct bene t is that it …  Lire la suite

• Zheng, Sixu

  2016 — Enhanced Heat and Mass Transfer for Alkane Solvent(s)-CO2-Heavy Oil Systems at High Pressures and Elevated Temperatures

  Résumé

  The tremendous heavy oil reserves have recently attracted considerable attention for sustaining the increasing global oil consumption. Heavy oil reservoirs are characterized by high oil viscosity and drastic drop of reservoir pressure in a short period during production, imposing great challenges to recover such heavy oil resources. In practice, conventional steam-based thermal recovery techniques are generally ineffective or uneconomical in thin heavy oil reservoirs due to operational and environmental constraints. Since CO2 is a highly soluble, low cost, and environment-friendly injectant, hot CO2 injection is alternatively considered to be a promising technique for enhancing heavy oil recovery from these thin …  Lire la suite

• Zhou, Yang

  2016 — Development of Stochastic Factorial Programming Methods for Water Resources Management Under Uncertainty

  Résumé

  Freshwater is a limited and vital natural resource on earth. It also plays a key role in advancing social and economic development. Despite its importance, freshwater is still one of the most vulnerable resources that have not been managed in a proper manner. There is growing recognition in public and private sectors that freshwater resource needs to be effectively conserved, managed, and distributed. This aspiration makes water resources management a prevalent topic from regional to national levels. The need for sustainable water resources management has become even more urgent with the status quo of global water scarcity. In this dissertation, …  Lire la suite