Fractured reservoirs, fault hydraulic behavior and mechanical instability

所有天然地下储层都以断层和天然裂缝为特征，影响流体循环。根据沉积盆地的构造演化，应力和盛行压力的状态，断层和裂缝可能是封闭的或泄漏的。由于储层流体可能含有碳氢化合物，并能传递热量和危险化学品，断层和裂缝的透射性对石油勘探、地热能、二氧化碳储存和废物处理具有重要影响。此外，在枯竭或注入作业期间，断层不稳定可能导致诱发地震活动和顶封破裂。我建议研究天然和水力裂缝和断层对流动单元的应力分布和状态、压力状态和渗透率的影响。分析断层的构造、封闭性和剪切滑移势，探讨断层接力带和断裂集的意义。研究将涉及露头的结构研究、地球物理数据的解释和耦合油藏地质力学数值模拟。HQP将有机会进行实地和实验室的地质和地球物理调查。我的目标是建立断层作为地下储层屏障或通道的预测模型，以及断层在地应力和孔隙压力变化下的再激活潜力。研究成果将应用于不同构造环境下的沉积盆地（伸展、走滑和挤压），包括常规的Volve油田（北海）和非常规的McCully气田（New Brunswick）、Fox Creek地区（Alberta中西部）和Horn River盆地（NE British Columbia）。在断层和裂缝检测、断层水力行为和地下机械不稳定性方面发展专业知识，对于提高油气勘探和开采效率以及非常规油藏水力压裂作业的安全性都非常重要。McCully油田、Fox Creek地区和Horn River盆地非常规资源开发的潜在向上流体运移到浅层含水层以及诱发地震活动的风险是这些地区的主要环境问题。本文提出的储层-地质力学耦合建模和断层传导率与注入作业引起的力学失稳关系的敏感性分析，将有助于减轻活产区油气开发对环境的潜在影响。

All natural subsurface reservoirs are characterized by faults and natural fractures that influence fluid circulation. Depending on the tectonic evolution of a sedimentary basin, the state of stress and prevailing pressure, faults and fractures may be sealing or leaking. Because reservoir fluids may contain hydrocarbons and can transport heat and hazardous chemicals, the transmissivity of faults and fractures have important consequences for petroleum exploration, geothermal energy, CO2 storage and waste-disposal. Additionally, fault instability during depletion or injection operations may result in induced seismicity and topseal breaching.    I propose to investigate the influence of natural and hydraulic fractures and faults on the distribution and state of stresses, pressure regimes, and permeability of flow units. The fault architecture, sealing capacity and shear slip potential of faults will be analyzed, and the significance of fault relay zones and fracture sets examined. Research will involve structural studies of outcrops, interpretation of geophysical data and coupled reservoir geomechanical numerical simulations. HQP will be provided with the opportunity to undertake field- and laboratory-based geological and geophysical investigations. My goal is to build predictive models for faults as barriers or channels in subsurface reservoirs and for fault reactivation potential under the in situ stress and pore pressure changes. Realization of the proposed research will be applied to sedimentary basins at different tectonic settings (extensional, strike-slip and compressional regime), including the conventional Volve oil field (North Sea) and unconventional plays of the McCully gas field (New Brunswick), Fox Creek area (West-central Alberta) and Horn River Basin (NE British Columbia).    Developing expertise in fault and fracture detection, fault hydraulic behavior and mechanical instability in the subsurface is important both for increasing efficiency of hydrocarbon exploration and extraction and for safety of hydraulic fracturing operations in unconventional reservoirs. Potential upward fluid migration to shallow aquifers and risk of induced seismicity related to unconventional resource development in the McCully field, Fox Creek area and Horn River Basin represent major environmental concerns for these regions. The proposed coupled reservoir-geomechanical modeling and sensitivity analysis on the relationship of fault transmissivity and mechanical instability caused by injection operations will help to mitigate potential environmental impacts of hydrocarbon development in active production areas.