Fracturing of shales via in-situ pore fluid pressurization by electromagnetic heating

该研究项目涉及非常规石油开采，重点是限制在含有互层页岩的非均质油砂油藏就地开采石油时使用水的新技术。夹层页岩是分布在油砂储层中的大型横向粘土状侵入体，阻碍了蒸汽在SAGD(蒸汽辅助重力排水)中的传播，从而阻碍了石油生产。由于页岩材料的低渗透性，通过蒸汽注入导致页岩破裂需要高压和相当大的用水量。取而代之的是，页岩中的水通过电磁波的穿透而受到热刺激，就像在家用微波炉中烹饪食物一样。 这项研究的主要目的是开发一种使用电磁就地加热方案来压裂页岩和邻近油砂的方法，该方案可以诱导孔隙流体的热加压，并从粘土颗粒中释放游离水。这将通过包括实验室实验、本构和数值模拟工作的综合方法实现：(1)在宏观、细观和微观三个尺度上了解电磁波存在下页岩的热孔力学行为，(2)实验室三轴测试，以再现通过内部探头在电磁波作用下页岩样品中的现场孔隙流体压力，以及(3)对破裂现象进行多尺度数值模拟，并实施到计算代码中，以在储层尺度上模拟过程。将使用页岩的颗粒状描述，其中纳米级堆积的粘土小片形成亚微米级粘土集合体颗粒，这些颗粒通过短程和长程作用力相互作用。 拟议的研究将与卡尔加里的几个领先的行业合作伙伴密切合作进行，这些合作伙伴包括计算机建模集团有限公司、帝国石油有限公司、赫斯基能源公司和BitCan公司。CMG油藏模拟基金会也承诺为这一战略项目提供资金支持。

The research project relates to unconventional oil extraction with a focus on new technologies to limit the use of water in the in-situ recovery of oil from heterogeneous oil sand reservoirs containing interbedded shales. Interbedded shales are large lateral clay-like intrusions interspersed within the oil sand reservoir that hinder the propagation of steam in SAGD (Steam Assisted Gravity Drainage), and hence oil production. Inducing the failure of shale by steam injection would require high pressures and considerable water usage because of low permeability of the material. Instead, the water within the shale is thermally excited by penetration of an electromagnetic (EM) wave just as when cooking food in a domestic microwave oven. The main objective of the research is to develop a method for fracturing the shales and adjacent oil sand using an electromagnetic in-situ heating scheme that induces thermal pressurization of the pore fluid and frees up the unbound water from the clay particles. This will be achieved following an integrated approach involving lab experimental, constitutive and numerical modelling works through: (1) Understanding of thermo-poro-mechanical behaviour of shales in the presence of electromagnetic waves at three scales, i.e. macro-, meso- and micro-scales, (2) Lab triaxial testing in order to reproduce the in-situ pore fluid pressurization in a shale sample subjected to EM wave via an internal probe, and (3) Multi-scale numerical modelling of the fracturing phenomenon and implementation into a computational code to model the process at the reservoir scale. A granular description of shale will be used in which stacked clay platelets at the nano-scale form sub-micron clay aggregates grains that interact with each other through both short- and long-range forces. The proposed research will be undertaken in close collaboration with several leading industry partners in Calgary, namely, Computer Modelling Group Ltd., Imperial Oil Ltd., Husky Energy, and BitCan Inc. CMG Reservoir Simulation Foundation has also committed to financially support this strategic project.