Investigating Multiphase Flow in Shales by Measuring Relative Permeabilities for Sustainable Hydrocarbon Recovery

拟议的研究计划将开发新的实验室和数学技术来研究和模拟孔隙尺度上的相分布、岩心尺度上的相相对渗透率（导流率）以及页岩储层现场尺度上的多相产量。在自然界中，页岩具有1)生烃烃源岩的作用；(2)储层自生生烃；(3)盖层封闭常规储层或地下储层。了解页岩多相流的物理特性是模拟烃源岩向储层运移、上覆页岩中温室气体和废弃物的储存以及页岩储层油气开采的关键。由于页岩的孔隙度和渗透率极低，且孔隙结构复杂，目前尚无实验室方案来测量页岩的相对渗透率。该研究将在两个互补的实验和建模阶段进行。在A阶段的第一部分，将通过1)分析扫描电镜图像和2)测量和分析岩心样品的相吸、熔融、冻结和蒸汽冷凝来表征各种加拿大页岩样品的亲水和疏水孔隙的尺寸分布。然后，通过控制吸油时间、蒸汽压或岩心温度，进行一系列特殊的岩心驱油试验，测量超低排量和不同饱和度条件下的相相对渗透率。A阶段的测量数据将在B阶段进行数学分析，以模拟页岩样品中代表疏水和亲水孔隙的混合湿孔网络。然后，我们将模拟油相、水相和气相通过孔隙网络的流动，计算相对渗透率曲线，并将其与a阶段的测量结果进行比较。测量和建模数据将用于评估、预测和优化油田规模的页岩开发项目的性能。该研究项目将由3名博士和2名硕士学生进行，其结果将提高对有机页岩中水、油和气同时流动过程中发生的复杂动态现象的理解。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页岩储层的剩余油量，并开发出回收剩余油的补充技术。预测和延长页岩油和致密油项目的经济寿命具有重要的战略意义，因为加拿大有许多含大量剩余油的致密非常规油藏。这可能会减少钻更多井的需求。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 will develop novel laboratory and mathematical techniques to study and model phase distribution at the pore-scale, phase relative permeability (flow conductance) at the core scale, and multi-phase production rate at the field scale of shale reservoirs. In nature, shales serve as i) source rocks generating hydrocarbon; ii) reservoir rocks self-generating and producing hydrocarbon, and iii) cap rocks sealing conventional reservoir rocks or underground storage sites. Understanding the physics of multiphase flow in shales is the key for modelling primary hydrocarbon migration from source to reservoir rocks, storing greenhouse gases and waste materials in overlying shales, and producing hydrocarbon from shale reservoirs. Currently there is no laboratory protocol for measuring relative permeability of shales mainly because of their extremely low porosity and permeability and complex pore structure. The research will be conducted in two complementary experimental and modelling phases. In the first part of Phase A, size distributions of hydrophilic and hydrophobic pores of various Canadian shale samples will be characterized by 1) analyzing scanning electron microscopy images and 2) by measuring and analyzing phase imbibition, melting, freezing, and vapor condensation in core samples. Then, a series of special coreflooding tests will be conducted to measure phase relative permeability under ultra-low flowrate and under different saturation conditions achieved by controlling liquid imbibition time, vapor pressure, or core temperature. The measured data of Phase A, will be mathematically analyzed in Phase B, to simulate mixed-wet pore networks representing hydrophobic and hydrophilic pores of the shale samples. Then, we will simulate the flow of oleic, aqueous, and gaseous phases through the pore networks to calculate the relative permeability curves and compare them with those measured in Phase A. The measured and modelled data will be used to evaluate, predict, and optimize the performance of field-scale shale-development projects. The results of this research program, which will be conducted by 3 PhD and 2 MSc students, will develop an improved understanding of complex dynamic phenomena occurring during simultaneous flow of water, oil, and gas in organic shales. In addition to the scientific impacts, this research will help the oil industry estimate the amount of oil remaining in shale reservoirs after the operations and develop complementary techniques for recovering the remaining oil. Predicting and extending the economic life of shale and tight oil projects is important strategically since there are many stimulated tight unconventional reservoirs in Canada containing a significant amount of residual oil. This will potentially reduce the need to drill more wells. Therefore, the outcomes of this research will help the industry indirectly to reduce the cost and environmental impacts per barrel of oil produced.