Predictions of fluid distribution,stress field,and natural fracture are essential for exploiting unconventional shale gas reservoirs.Given the high likelihood of tilted fractures in subsurface formations,this study fo...Predictions of fluid distribution,stress field,and natural fracture are essential for exploiting unconventional shale gas reservoirs.Given the high likelihood of tilted fractures in subsurface formations,this study focuses on simultaneous seismic inversion to estimate fluid bulk modulus,effective stress parameter,and fracture density in the tilted transversely isotropic(TTI)medium.In this article,a novel PP-wave reflection coefficient approximation equation is first derived based on the constructed TTI stiffness matrix incorporating fracture density,effective stress parameter,and fluid bulk modulus.The high accuracy of the proposed equation has been demonstrated using an anisotropic two-layer model.Furthermore,a stepwise seismic inversion strategy with the L_(P) quasi-norm sparsity constraint is implemented to obtain the anisotropic and isotropic parameters.Three synthetic model tests with varying signal-to-noise ratios(SNRs)confirm the method's feasibility and noise robustness.Ultimately,the proposed method is applied to a 3D fractured shale gas reservoir in the Sichuan Basin,China.The results have effectively characterized shale gas distribution,stress fields,and tilted natural fractures,with validation from geological structures,well logs,and microseismic events.These findings can provide valuable guidance for hydraulic fracturing development,enabling more reliable predictions of reservoir heterogeneity and completion quality.展开更多
The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sens...The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sensitivity(IS)in students serves as an effective approach to detect psychological problems and provide timely intervention.In this study,958 freshmen from higher education institutions in Zhejiang Province were selected as participants.We proposed a Multi-Strategy Artemisinin Optimization(MSAO)algorithm by enhancing the Artemisinin Optimization(AO)framework through the integration of a group-guided elimination strategy and a two-stage consolidation strategy.Subsequently,the MSAO was combined with the Fuzzy K-Nearest Neighbor(FKNN)classifier to develop the bMSAO-FKNN predictive model for assessing college students’IS.The proposed algorithm’s efficacy was validated through the CEC 2017 benchmark test suite,while the model’s performance was evaluated on the IS dataset,achieving an accuracy rate of 97.81%.These findings demonstrate that the bMSAO-FKNN model not only ensures high predictive accuracy but also offers interpretability for IS prediction,making it a valuable tool for mental health monitoring in academic settings.展开更多
基金financially supported by the Natural Science Foundation of Sichuan Province(Grant Nos.2023NSFSC0767 and2024NSFSC0809)the China Postdoctoral Science Foundation(Grant No.2024MF750281)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20230326)。
文摘Predictions of fluid distribution,stress field,and natural fracture are essential for exploiting unconventional shale gas reservoirs.Given the high likelihood of tilted fractures in subsurface formations,this study focuses on simultaneous seismic inversion to estimate fluid bulk modulus,effective stress parameter,and fracture density in the tilted transversely isotropic(TTI)medium.In this article,a novel PP-wave reflection coefficient approximation equation is first derived based on the constructed TTI stiffness matrix incorporating fracture density,effective stress parameter,and fluid bulk modulus.The high accuracy of the proposed equation has been demonstrated using an anisotropic two-layer model.Furthermore,a stepwise seismic inversion strategy with the L_(P) quasi-norm sparsity constraint is implemented to obtain the anisotropic and isotropic parameters.Three synthetic model tests with varying signal-to-noise ratios(SNRs)confirm the method's feasibility and noise robustness.Ultimately,the proposed method is applied to a 3D fractured shale gas reservoir in the Sichuan Basin,China.The results have effectively characterized shale gas distribution,stress fields,and tilted natural fractures,with validation from geological structures,well logs,and microseismic events.These findings can provide valuable guidance for hydraulic fracturing development,enabling more reliable predictions of reservoir heterogeneity and completion quality.
文摘The mental health issues of college students have become an increasingly prominent social problem,exerting severe impacts on their academic performance and overall well-being.Early identification of Interpersonal Sensitivity(IS)in students serves as an effective approach to detect psychological problems and provide timely intervention.In this study,958 freshmen from higher education institutions in Zhejiang Province were selected as participants.We proposed a Multi-Strategy Artemisinin Optimization(MSAO)algorithm by enhancing the Artemisinin Optimization(AO)framework through the integration of a group-guided elimination strategy and a two-stage consolidation strategy.Subsequently,the MSAO was combined with the Fuzzy K-Nearest Neighbor(FKNN)classifier to develop the bMSAO-FKNN predictive model for assessing college students’IS.The proposed algorithm’s efficacy was validated through the CEC 2017 benchmark test suite,while the model’s performance was evaluated on the IS dataset,achieving an accuracy rate of 97.81%.These findings demonstrate that the bMSAO-FKNN model not only ensures high predictive accuracy but also offers interpretability for IS prediction,making it a valuable tool for mental health monitoring in academic settings.
