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

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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.