gAn integrated eophysical, geodetic, geomechanical and geochemical study of CO2 storage in subsurface reservoirs

捕获燃煤电厂排放的二氧化碳并将其储存在地下深处的油藏（如成熟的油藏）中是可能的。这种碳捕获与封存（CCS）技术已经证明了在满足世界能源需求的同时减少人类温室气体排放的潜力。此外，如果CCS允许下一代清洁煤电厂的发展，作为新的“绿色经济”的一部分，它将为英国经济创造约65亿英镑的价值，创造10万个就业机会。然而，为了保证储存的安全性，必须有监测方法来跟踪二氧化碳在地下的运动，并对二氧化碳注入对地下岩石的影响进行成像。当二氧化碳注入储层时，压力变化会导致储层膨胀，导致储层和提供密封的上覆岩石变形。如果断层和裂缝打开，二氧化碳从目标储层中逸出，地质力学变形可能会导致CCS站点出现问题。我建议在CCS站点进行地质力学变形研究，使用地球物理技术监测变形，并生成计算机模型来模拟变形。盖层中的裂缝会产生地震能量，这些能量可以通过检波器阵列检测到。通过检测这些微地震发射，可以确定地下对二氧化碳注入的反应。水库的膨胀可以推高上覆岩石，引起地面隆起，这可以用卫星监测。我的项目将分析在阿尔及利亚萨拉赫和加拿大韦伯恩两个CCS站点检测到的微地震事件。我还将在In Salah研究高质量的地表隆起数据。通过定位微地震发射的震源，可以识别出正在发生变形的区域，如果事件聚集在离散的表面上，可以识别出地下活跃变形的断层。活动断裂的识别是认识储层上方地质力学变形的关键。微地震事件的位置可以与地表隆起的观测结果进行比较，从而描绘出由注入引起的变形的总体情况。我将使用事件位置和地表变形来校准和基准地质力学模型，区分那些能很好地预测微震活动的模型和那些不能的模型。通过以这种方式校准我的地质力学模型，我可以确定那些可能给出良好预测的模型，从而评估变形造成的泄漏风险。连接地球物理数据、大地测量数据（地表变形）和地质信息以建立地质力学模型的能力对于确定变形引起的泄漏风险至关重要。地质力学变形的计算机模型可以用来确定储层的形状和材料性质如何影响力学响应。这将有助于选择不会有变形风险的位置，以及设计注入方案，将裂缝泄漏的风险降至最低。我的总体目标是生成一本处理CCS站点地质力学变形的最佳实践手册。该项目将与in Salah油田的运营商、BP和加拿大地质调查局合作进行。欧盟计划在2015年之前实施至少12个CCS示范项目，因此我的项目是及时的，因为它将提供在这些地点开始注入之前处理地质力学变形的最佳实践手册。

It is possible to capture emissions of CO2 from coal-fired power plants and store them in deep subsurface reservoirs such as mature oil reservoirs. This Carbon Capture and Storage (CCS) technology has demonstrated the potential to reduce mankind's greenhouse gas emissions while meeting the world's energy needs. Furthermore, if CCS allows the development of the next generation of clean coal power plants, it will be worth an estimated £6.5billion to the U.K. economy, creating 100 000 jobs, as part of the new 'green economy'. However, to guarantee security of storage, monitoring methods must be in place that can track the movements of CO2 through the subsurface, and image the effects of CO2 injection on the subsurface rocks. When CO2 is injected into reservoirs, the pressure changes can lead to expansion of the reservoir, resulting in deformation of both the reservoir and the overlying rocks that provide the seal. Geomechanical deformation can cause problems at CCS sites if faults and fractures open, allowing CO2 to escape from the target reservoir. I propose a study of geomechanical deformation at CCS sites, using geophysical techniques to monitor deformation, and generating computer models to simulate deformation. Fractures in the caprock will generate seismic energy, which can be detected on geophone arrays. By detecting these microseismic emissions, it is possible to determine how the subsurface is responding to CO2 injection. The inflation of the reservoir can push up overlying rocks, causing uplift of the ground surface, which can be monitored with satellites. My project will analyse microseismic events detected at two CCS sites - In Salah, Algeria, and Weyburn, Canada. I will also study high quality surface uplift data at In Salah. By locating the hypocenters of microseismic emissions, it will be possible to identify regions where deformation is occurring, and, if events cluster onto discrete surfaces, to identify actively deforming faults in the subsurface. The identification of active faults is crucial for understanding the geomechanical deformation above the reservoir. The locations of microseismic events can be compared with observations of surface uplift to paint an overall picture of the deformation induced by injection. I will use event locations and surface deformation to calibrate and benchmark geomechanical models, distinguishing between models that do a good job of predicting microseismicity and those that do not. By calibrating my geomechanical models in this manner I can determine those that are likely to give good predictions going forward, and thereby assess the risks of leakage due to deformation. The ability to link geophysical data, geodetic data (surface deformation), and geological information to build geomechanical models is crucial for determining the risks of leakage due to deformation. Computer models of geomechanical deformation can be used to determine how the shape and material properties of the reservoir influence the mechanical response. This will be useful in selecting sites that will not be at risk from deformation, and in designing injection regimes that minimise risk of leakage through fractures. My overall aim is to generate a manual of best practice for dealing with geomechanical deformation at CCS sites. The project will be conducted in collaboration with the operators of the In Salah fields, BP and the Geological Survey of Canada. The EU intends to implement at least 12 CCS demonstrations projects by 2015, so my project is timely in that it will provide a manual of best practice for dealing with geomechanical deformation before injection begins at these sites.