The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian Sea.The measured physical parameters included mean ...The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian Sea.The measured physical parameters included mean grain size,mass density,bulk density,salinity,porosity,permeability,pore size and mineralogical composition.Acoustic properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transmission method and Fourier transform techniques was utilized to examine the sound propagation and absorption of novel seabed sediments.The standard deviation of mean sound speed in fresh water was 0.75 m/s,and attenuation was observed in the range of 0.43 to 0.61 dB/m.The mean sound velocity in sand and clay varied from 1706 to 1709 m/s and 1602 to 1608 m/s,respectively.Corresponding average attenuation was observed at 80 to 93 dB/m in sandy sediments and from 31.8 to 38.6 dB/m in clayey sediments.Sound velocity variation within sandy sediment is low,consistent with expected results,and smaller than the predicted uncertainty.However,clay sediment exhibited a positive linear correlation and low sound speed variation.Attenuation increased linearly with frequency for both sediments.Finally,the laboratory results were validated by using the Biot−Stoll model.The dispersion of sound speed in sandy and clayey sediments was consistent with the predictions of the Biot−Stoll model.Measured attenuation aligned more with Biot−Stoll model predictions due to improved permeability,tortuosity and pore size parameter fitting.展开更多
In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes s...In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes significant seismic velocity dispersion and attenuation. To establish the relation between seismic response and type of fluids, we designed a rock physics model for carbonates. First, we performed CT scanning and analysis of the fluid distribution in the partially saturated rocks. Then, we predicted the quantitative relation between the wave response at different frequency ranges and the basic lithological properties and pore fluids. A rock physics template was constructed based on thin section analysis of pore structures and seismic inversion. This approach was applied to the limestone gas reservoirs of the right bank block of the Amu Darya River. Based on poststack wave impedance and prestack elastic parameter inversions, the seismic data were used to estimate rock porosity and gas saturation. The model results were in good agreement with the production regime of the wells.展开更多
Biot’s model is a multiphysics model that describes the interaction of a poroelastic material with its interstitial fluid flow.In this study,we focus on investigating the convergence behavior of a global-in-time iter...Biot’s model is a multiphysics model that describes the interaction of a poroelastic material with its interstitial fluid flow.In this study,we focus on investigating the convergence behavior of a global-in-time iterative decoupled algorithm based on a three-field formulation.During each iteration,the algorithm involves solving a reaction-diffusion subproblem across the entire temporal domain,followed by resolving a Stokes subproblem over the same time interval.This algorithm is recognized for its "partially parallel-in-time" property,enabling the implementation of a parallel procedure when addressing the Stokes subproblem.We establish its global convergence with a new technique by confirming that the limit of the sequence of numerical solutions of the global-in-time algorithm is the numerical solution of the fully coupled algorithm.Numerical experiments validate the theoretical predictions and underline the efficiency gained by implementing the parallel procedure within the proposed globalin-time algorithm.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.12074088).
文摘The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian Sea.The measured physical parameters included mean grain size,mass density,bulk density,salinity,porosity,permeability,pore size and mineralogical composition.Acoustic properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transmission method and Fourier transform techniques was utilized to examine the sound propagation and absorption of novel seabed sediments.The standard deviation of mean sound speed in fresh water was 0.75 m/s,and attenuation was observed in the range of 0.43 to 0.61 dB/m.The mean sound velocity in sand and clay varied from 1706 to 1709 m/s and 1602 to 1608 m/s,respectively.Corresponding average attenuation was observed at 80 to 93 dB/m in sandy sediments and from 31.8 to 38.6 dB/m in clayey sediments.Sound velocity variation within sandy sediment is low,consistent with expected results,and smaller than the predicted uncertainty.However,clay sediment exhibited a positive linear correlation and low sound speed variation.Attenuation increased linearly with frequency for both sediments.Finally,the laboratory results were validated by using the Biot−Stoll model.The dispersion of sound speed in sandy and clayey sediments was consistent with the predictions of the Biot−Stoll model.Measured attenuation aligned more with Biot−Stoll model predictions due to improved permeability,tortuosity and pore size parameter fitting.
基金sponsored by the NSFC(41104066)973 Program of China(No.2014CB239006)+1 种基金NSTMP of China(Nos.2011ZX05004-003 and 2011ZX05029-003)12th 5-Year Basic Research Program of CNPC(No.2011A-3601)
文摘In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes significant seismic velocity dispersion and attenuation. To establish the relation between seismic response and type of fluids, we designed a rock physics model for carbonates. First, we performed CT scanning and analysis of the fluid distribution in the partially saturated rocks. Then, we predicted the quantitative relation between the wave response at different frequency ranges and the basic lithological properties and pore fluids. A rock physics template was constructed based on thin section analysis of pore structures and seismic inversion. This approach was applied to the limestone gas reservoirs of the right bank block of the Amu Darya River. Based on poststack wave impedance and prestack elastic parameter inversions, the seismic data were used to estimate rock porosity and gas saturation. The model results were in good agreement with the production regime of the wells.
基金support by National NSF of China No.123B2016supported by the National NSF of China No.11971221+4 种基金the Shenzhen Sci-Tech Fund Nos.RCJC20200714114556020,JCYJ20170818153840322 and JCYJ20190809150413261Guangdong Provincial Key Laboratory of Computational Science and Material Design No.2019B030301001Guang-Dong Basic and Applied Basic Research Foundation 2023B1515250005supported in part by NIH-RCMI grant through U54MD013376,the affiliated project award from the Center for Equitable Artificial Intelligence and Machine Learning Systems(CEAMLS)at Morgan State University(project ID 02232301)the National Science Foundation award 1831950.
文摘Biot’s model is a multiphysics model that describes the interaction of a poroelastic material with its interstitial fluid flow.In this study,we focus on investigating the convergence behavior of a global-in-time iterative decoupled algorithm based on a three-field formulation.During each iteration,the algorithm involves solving a reaction-diffusion subproblem across the entire temporal domain,followed by resolving a Stokes subproblem over the same time interval.This algorithm is recognized for its "partially parallel-in-time" property,enabling the implementation of a parallel procedure when addressing the Stokes subproblem.We establish its global convergence with a new technique by confirming that the limit of the sequence of numerical solutions of the global-in-time algorithm is the numerical solution of the fully coupled algorithm.Numerical experiments validate the theoretical predictions and underline the efficiency gained by implementing the parallel procedure within the proposed globalin-time algorithm.
