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Juan E Santos - One of the best experts on this subject based on the ideXlab platform.
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Seismic modeling to monitor co2 geological storage the atzbach schwanenstadt gas field
Journal of Geophysical Research, 2012Co-Authors: Stefano Picotti, Jose M Carcione, Davide Gei, Giuliana Rossi, Juan E SantosAbstract:[1] We develop a petro-elastical numerical Methodology to compute realistic synthetic seismograms and analyze the sensitivity of the Seismic response when injecting carbon dioxide (CO2) in a depleted gas reservoir. The petro-elastical model describes the Seismic properties of the reservoir rock saturated with CO2, methane and brine, and allows us to estimate the distribution and saturation of CO2 during the injection process. The gas properties, as a function of the in-situ pressure and temperature conditions, are computed with the Peng-Robinson equation of state, taking into account the absorption of gas by brine. Wave attenuation and velocity dispersion are based on the mesoscopic loss mechanism, which is simulated by an upscaling procedure to obtain an equivalent viscoelastic medium corresponding to partial saturation at the mesoscopic scale. Having the equivalent complex and frequency-dependent bulk (dilatational) modulus, we include shear attenuation and perform numerical simulations of wave propagation at the macroscale by solving the viscoelastic differential equations using the memory-variable approach. The pseudo-spectral modeling Method allows general material variability and provides a complete and accurate characterization of the reservoir. The Methodology is used to assess the sensitivity of the Seismic Method for monitoring the CO2 geological storage at the Atzbach-Schwanestadt depleted gas-field in Austria. The objective of monitoring is the detection of the CO2 plume in the reservoir and possible leakages of CO2. The leakages are located at different depths, where the CO2 is present as gaseous, liquid and supercritical phases. Even though the differences can be very subtle, this work shows that Seismic monitoring of CO2 from the surface is possible. While the identification of shallow leakages is feasible, the detection of the plume and deep leakages, located in the caprock just above the injection formation, is more difficult, but possible by using repeatability metrics, such as the normalized RMS (NRMS) images. Considering real-data conditions, affected by random noise, a reference detection threshold for deep leakages and the CO2 plume in the reservoir corresponds to a signal-to-noise ratio of about 10 dB.
Jingsheng Fan - One of the best experts on this subject based on the ideXlab platform.
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the exploration of sedimentary bauxite deposits using the reflection Seismic Method a case study from the henan province china
Ore Geology Reviews, 2020Co-Authors: Guoqiang Xue, Wenbo Guo, Jingsheng FanAbstract:Abstract Sedimentary bauxite usually occurs in gently dipping or monoclinic folded formations. The roof of syncline bauxite tends to be flat and the bottom appears to be similar to a concave bucket. Until recently, mainly non-Seismic geophysical exploration Methods, such as gravity, magnetic, and electrical Methods, have been used in the exploration of syncline bauxite deposits. However, both the thickness and depth of bauxite deposits can vary significantly. Therefore, gravity, magnetic, electrical, and other non-Seismic Methods have technical limitations, especially when planning exploration drill targets. By contrast, Seismic Methods have advantages in the exploration of concealed bauxite deposits due to their high vertical resolution. In this study, reflection Seismics are adopted to detect bauxite layers in China’s Henan Province. It is observed that strong reflection interfaces (positive phases) appeared on the top surfaces of the bauxite layers. Meanwhile, weak reflection interfaces (both positive and negative phases are recorded) appeared on the upper surface of the lower overlying limestone layer. Seismic reflection Methods cannot only define the shape and structure of the bauxite layers, but also indicating their relative depth and thickness, respectively. Importantly, subsequent exploration drilling confirmed our Seismic interpretation.
Bin Liu - One of the best experts on this subject based on the ideXlab platform.
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The Practice of Forward Prospecting of Adverse Geology Applied to Hard Rock TBM Tunnel Construction: The Case of the Songhua River Water Conveyance Project in the Middle of Jilin Province
Elsevier, 2018Co-Authors: Lichao Nie, Bin LiuAbstract:An increasing number of tunnels are being constructed with tunnel-boring machines (TBMs) due to the increased efficiency and shorter completion time resulting from their use. However, when a TBM encounters adverse geological conditions in the course of tunnel construction (e.g., karst caves, faults, or fractured zones), disasters such as water and mud inrush, collapse, or machine blockage may result, and may severely imperil construction safety. Therefore, the advance detection of adverse geology and water-bearing conditions in front of the tunnel face is of great importance. This paper uses the TBM tunneling of the water conveyance project from Songhua River as a case study in order to propose a comprehensive forward geological prospecting technical system that is suitable for TBM tunnel construction under complicated geological conditions. By combining geological analysis with forward geological prospecting using a three-dimensional (3D) induced polarization Method and a 3D Seismic Method, a comprehensive forward geological prospecting technical system can accurately forecast water inrush geo-hazards or faults in front of the TBM tunnel face. In this way, disasters such as water and mud inrush, collapse, or machine blockage can be avoided. This prospecting technical system also has reference value for carrying out the forward prospecting of adverse geology for potential TBM tunneling and for ensuring that a TBM can work efficiently. Keywords: Hard rock TBM tunnels, Comprehensive forward prospecting, Geological analysis, 3D induced polarization, 3D Seismic Method, Adverse geolog
Shucai Li - One of the best experts on this subject based on the ideXlab platform.
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the practice of forward prospecting of adverse geology applied to hard rock tbm tunnel construction the case of the songhua river water conveyance project in the middle of jilin province
Engineering, 2018Co-Authors: Shucai LiAbstract:Abstract An increasing number of tunnels are being constructed with tunnel-boring machines (TBMs) due to the increased efficiency and shorter completion time resulting from their use. However, when a TBM encounters adverse geological conditions in the course of tunnel construction (e.g., karst caves, faults, or fractured zones), disasters such as water and mud inrush, collapse, or machine blockage may result, and may severely imperil construction safety. Therefore, the advance detection of adverse geology and water-bearing conditions in front of the tunnel face is of great importance. This paper uses the TBM tunneling of the water conveyance project from Songhua River as a case study in order to propose a comprehensive forward geological prospecting technical system that is suitable for TBM tunnel construction under complicated geological conditions. By combining geological analysis with forward geological prospecting using a three-dimensional (3D) induced polarization Method and a 3D Seismic Method, a comprehensive forward geological prospecting technical system can accurately forecast water inrush geo-hazards or faults in front of the TBM tunnel face. In this way, disasters such as water and mud inrush, collapse, or machine blockage can be avoided. This prospecting technical system also has reference value for carrying out the forward prospecting of adverse geology for potential TBM tunneling and for ensuring that a TBM can work efficiently.
Guoqiang Xue - One of the best experts on this subject based on the ideXlab platform.
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the exploration of sedimentary bauxite deposits using the reflection Seismic Method a case study from the henan province china
Ore Geology Reviews, 2020Co-Authors: Guoqiang Xue, Wenbo Guo, Jingsheng FanAbstract:Abstract Sedimentary bauxite usually occurs in gently dipping or monoclinic folded formations. The roof of syncline bauxite tends to be flat and the bottom appears to be similar to a concave bucket. Until recently, mainly non-Seismic geophysical exploration Methods, such as gravity, magnetic, and electrical Methods, have been used in the exploration of syncline bauxite deposits. However, both the thickness and depth of bauxite deposits can vary significantly. Therefore, gravity, magnetic, electrical, and other non-Seismic Methods have technical limitations, especially when planning exploration drill targets. By contrast, Seismic Methods have advantages in the exploration of concealed bauxite deposits due to their high vertical resolution. In this study, reflection Seismics are adopted to detect bauxite layers in China’s Henan Province. It is observed that strong reflection interfaces (positive phases) appeared on the top surfaces of the bauxite layers. Meanwhile, weak reflection interfaces (both positive and negative phases are recorded) appeared on the upper surface of the lower overlying limestone layer. Seismic reflection Methods cannot only define the shape and structure of the bauxite layers, but also indicating their relative depth and thickness, respectively. Importantly, subsequent exploration drilling confirmed our Seismic interpretation.
