报告人：张锐 (Rui Zhang)
报告简介: The In Salah carbon dioxide storage project in Algeria has injected over 3 million tonnes of carbon dioxide into a water-filled tight-sand formation. During injection interferometric Synthetic Aperture Radar (InSAR) revealed a doubled lobed pattern of surface uplift up to 20mm above a horizontal leg of an injection well. Our analysis indicates this surface uplift is associated with this well and comes from the injection of CO2. The depression between the two lobes is caused by an opening of a sub-vertical fracture or damage zone at depth above the injection interval, which allowed injected CO2 to migrate upward. Interpretation of 3D seismic data reveals the presence of a subtle linear push-down feature located along the InSAR determined surface depression between the two lobes, which we interpret to have been caused by the anomalously lower velocity of the fracture zone caused by the presence of CO2 displacing brine in this feature. To enhance the seismic interpretation, we calculated many seismic attributes, including positive and negative curvatures, from the post-stack 3D reflection seismic data. The maximum positive curvature attribute shows the clearest linear features, with two parallel trends, which agrees well with ant-tracking volumes and the InSAR observations of the depression zone. The seismic attributes provide a plausible characterization of the fracture zone extent, including height, width and length, which provide important information for further study of fracture behavior due to the CO2 injection.