An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning （Q＆P） process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interf...An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning （Q＆P） process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interface migration is excluded in constrained paraequilibrium （CPE） model. Based on ＂endpoint＂ predicted by CPE model the thermodynamic condition of interface migration is analyzed, that is, the difference in the chemical potential of iron in both ferrite （martenisite） and austenite produces the driving force of the iron atoms to migrate from one phase to the other phase. In addition, the interface migration can change the austenite fraction; as a result, the austenite fraction at partitioning temperature may be higher than that at quenching temperature through the interface migration, but this phenomenon cannot be explained by CPE model.展开更多
The propagation of seismic waves in viscous media,such as the loess plateau and shallow gas regions,alters their amplitude,frequency,and phase due to absorption attenuation,resulting in reductions in the resolution an...The propagation of seismic waves in viscous media,such as the loess plateau and shallow gas regions,alters their amplitude,frequency,and phase due to absorption attenuation,resulting in reductions in the resolution and fidelity of seismic profiles and the inaccurate identification of subtle structure and lithology.Q modeling and Q migration techniques proposed in this paper are used to compensate for the energy and frequency attenuation of seismic waves,obtain high-quality depth imaging results,and further enhance structural imaging to address the aforementioned problem.First,various prior information is utilized to construct an initial Q model.Q tomography techniques are employed to further optimize the precision of the initial Q model and build a high-precision Q model.Subsequently,Q prestack depth migration technology is employed to compensate for absorption and attenuation in the three-dimensional space along the seismic wave propagation path and correct the travel times,realizing the purposes of amplitude compensation,frequency recovery,and phase correction,which can help improve the wave group characteristics while enhancing the resolution.Model data and practical application results demonstrate that high-precision Q modeling and Q migration techniques can substantially improve the imaging quality of underground structures and formations in the loess plateau region with extremely complex surface and near-surface conditions.The resolution and fidelity of seismic data,as well as the capability to identify reservoirs,can be improved using these techniques.展开更多
文摘An Fe-0.2C-1.5Si-1.67Mn steel was subjected to quenching and partitioning （Q＆P） process, and the interface migration between martensite and austenite at an elevated partitioning temperature was observed. The interface migration is excluded in constrained paraequilibrium （CPE） model. Based on ＂endpoint＂ predicted by CPE model the thermodynamic condition of interface migration is analyzed, that is, the difference in the chemical potential of iron in both ferrite （martenisite） and austenite produces the driving force of the iron atoms to migrate from one phase to the other phase. In addition, the interface migration can change the austenite fraction; as a result, the austenite fraction at partitioning temperature may be higher than that at quenching temperature through the interface migration, but this phenomenon cannot be explained by CPE model.
基金supported by the China National Offshore Oil Corporation’s“14th Five-Year Plan”major scientific and technological project,“Key Technologies for Onshore Unconventional Natural Gas Exploration and Development”(KJGG2021-1000).
文摘The propagation of seismic waves in viscous media,such as the loess plateau and shallow gas regions,alters their amplitude,frequency,and phase due to absorption attenuation,resulting in reductions in the resolution and fidelity of seismic profiles and the inaccurate identification of subtle structure and lithology.Q modeling and Q migration techniques proposed in this paper are used to compensate for the energy and frequency attenuation of seismic waves,obtain high-quality depth imaging results,and further enhance structural imaging to address the aforementioned problem.First,various prior information is utilized to construct an initial Q model.Q tomography techniques are employed to further optimize the precision of the initial Q model and build a high-precision Q model.Subsequently,Q prestack depth migration technology is employed to compensate for absorption and attenuation in the three-dimensional space along the seismic wave propagation path and correct the travel times,realizing the purposes of amplitude compensation,frequency recovery,and phase correction,which can help improve the wave group characteristics while enhancing the resolution.Model data and practical application results demonstrate that high-precision Q modeling and Q migration techniques can substantially improve the imaging quality of underground structures and formations in the loess plateau region with extremely complex surface and near-surface conditions.The resolution and fidelity of seismic data,as well as the capability to identify reservoirs,can be improved using these techniques.
