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，以研究和模拟相分布在孔隙尺度，相相对渗透率（流导）在核心规模，并在现场规模的页岩油气藏的多相生产率。在自然界中，页岩用作i）生成烃的源岩; ii）自生和生产烃的储集岩，以及iii）密封常规储集岩或地下储存场所的盖岩。了解页岩中多相流的物理特性是模拟烃类从源岩到储集岩的初次运移、在上覆页岩中储存温室气体和废物以及从页岩储层中生产烃类的关键。由于页岩的孔隙度和渗透率极低，孔隙结构复杂，目前还没有实验室测量页岩相对渗透率的方法。 研究将分两个互补的实验和建模阶段进行。在阶段A的第一部分中，将通过1）分析扫描电子显微镜图像和2）测量和分析岩心样品中的相渗吸、熔化、冻结和蒸汽冷凝来表征各种加拿大页岩样品的亲水性和疏水性孔的尺寸分布。然后进行一系列特殊的岩心驱替试验，通过控制液体自吸时间、蒸汽压力或岩心温度来测量超低流量和不同饱和度条件下的相相对渗透率。阶段A的测量数据将在阶段B中进行数学分析，以模拟代表页岩样品的疏水和亲水孔隙的混合湿孔隙网络。然后，我们将模拟油相、水相和气相通过孔隙网络的流动，以计算相对渗透率曲线，并将其与相A中测量的曲线进行比较。测量和建模数据将用于评估，预测和优化现场规模页岩开发项目的性能。 该研究计划的结果将由3名博士和2名硕士学生进行，将提高对有机页岩中水，油和天然气同时流动过程中发生的复杂动态现象的理解。除了科学影响外，这项研究还将帮助石油行业估计作业后页岩储层中剩余的石油量，并开发回收剩余石油的补充技术。预测和延长页岩和致密油项目的经济寿命具有重要的战略意义，因为加拿大有许多受刺激的致密非常规油藏，其中含有大量的残余油。这将潜在地减少钻更多威尔斯井的需要。因此，这项研究的结果将有助于该行业间接降低每桶石油生产的成本和环境影响。

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.