Investigating Three-Phase Flow of Steam-Water-Oil in Porous Media for Maximizing SAGD Potential: A New Measurement Technique

提出的研究计划为多孔介质三相流动的基础研究开发了一种新的实验室技术和程序。测量数据将用于预测和优化加拿大稠油和沥青资源的原位热采油方法。阿尔伯塔省和萨斯喀彻温省有超过3000亿立方米的粘性沥青。这一巨大资源的三分之一就足以满足整个北美100多年的碳氢化合物需求。然而，只有20%的资源可以通过露天开采获得。另外80%需要采用原位方法，如蒸汽辅助重力泄放（SAGD）。SAGD已被证明是加拿大稠油和沥青开采中最成功的原位采油方法。在SAGD中，蒸汽、蒸汽凝析油和油同时流过岩石孔隙空间。数学建模和优化这些过程需要仔细测量实验室中每个相的导流率（相对渗透率）和剩余饱和度。然而，由于相饱和度（即体积分数）测量的困难，在实验室确定蒸汽、油和水的相对渗透率曲线非常具有挑战性。主要的挑战是区分具有相似密度的水相和油相。本研究的A阶段开发了一种新的非破坏性方法，用于测量同时流过岩心支架内多孔介质的油、水和蒸汽的饱和度。在该方法中，总油水饱和度（So + Sw）通过基于x射线的技术测量，水饱和度（Sw）通过基于电容（由介电常数描述）的技术测量。水的介电常数比油的介电常数高几倍，因此可以计算出每一相的比例。在时间和空间上测量的三相饱和度将被解释和建模，以获得饱和空间中每个点的三相相对渗透率。研究的第二阶段开发了数学技术，利用测量数据来评估、预测和优化油田规模SAGD项目的性能。现有的蒸汽室开发速率模型将得到改进，以考虑三相流的物理特性，这是基于蒸汽的缸内回收过程中不可避免的现象。这项研究的结果将由两名博士和两名硕士学生进行，预计将对多孔介质中蒸汽、水和油同时流动时发生的复杂动态现象有更好的理解。模拟存在蒸汽冷凝现象的三相油相对渗透率是一个具有挑战性的问题，在拟议的研究计划中，将通过进行仔细的实验室测量来研究。除了科学影响之外，这项研究还将帮助石油行业估计作业后储层中剩余的油量，并开发出回收剩余油的补充技术。由于加拿大有许多成熟的SAGD蒸汽室含有大量的石油和热能，因此预测和延长SAGD项目的经济寿命具有重要的战略意义。因此，本研究的结果将间接帮助该行业降低每桶石油生产的成本和对环境的影响。

The proposed research program develops a novel laboratory technique and procedure for fundamental study of three-phase flow in porous media. The measured data will be used for prediction and optimization of in-situ thermal recovery methods for oil production from Canada's heavy oil and bitumen resources. More than 300 billion cubic meters of viscous bitumen exist in Alberta and Saskatchewan. Only one-third of this huge resource is enough to meet the hydrocarbon requirements of all of North America for more than 100 years. However, only 20% of this resource is accessible through surface mining. The other 80% requires in-situ methods such as Steam Assisted Gravity Drainage (SAGD). SAGD has been proved to be the most successful in-situ recovery method for heavy oil and bitumen recovery in Canada. In SAGD, steam, steam-condensate, and oil simultaneously flow through the rock pore space. Mathematical modelling and optimizing such processes require careful measurement of flow conductance (relative permeability) and residual saturation of each phase in the laboratory. However, laboratory determination of relative permeability curves for steam, oil, and water is very challenging due to difficulties in phase saturation (i.e., volumetric fraction) measurement. The main challenge is to distinguish between the water and oil phases, which have similar densities. Phase A of this research develops a novel non-destructive method for measuring the saturation of oil, water and steam simultaneously flowing through a porous medium confined inside a core holder. In this method, the total oil and water saturation (So + Sw) is measured by a x-ray based technique, and water saturation (Sw) is measured by a capacitance (described by dielectric constant) based technique. The dielectric constant of water is several times higher than that of oil, which allows computing the fraction of each phase. The three-phase saturations measured in time and space will be interpreted and modelled to obtain three-phase relative permeabilities for each point in the saturation space. Phase B of the research develops mathematical techniques to use the measured data to evaluate, predict and optimize the performance of field-scale SAGD projects. The existing models for steam chamber development rate will be improved to account for the physics of three-phase flow, which is an inevitable phenomenon during steam-based in-stue recovery processes. The results of this study, which will be conducted by two PhD and two MSc students is anticipated to develop an improved understanding of complex dynamic phenomena occurring during simultaneous flow of steam, water, and oil in porous media. Modelling three-phase oil relative permeability in the presence of steam condensation phenomenon is a challenging problem, which will be studied by conducting careful laboratory measurements in the proposed research program. In addition to the scientific impacts, this research will help the oil industry to estimate the amount of oil remaining in the reservoir after the operations and to develop complementary techniques for recovering the remaining oil. Predicting and extending the economic life SAGD projects are important strategically since there are many mature SAGD steam chambers in Canada containing a significant amount of oil and heat energy. Therefore, the outcomes of this research will help the industry indirectly to 1) reduce the cost and environmental impacts per barrel of oil produced.