The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m.The average matrix porosity of the reservoir is 5.5%,and the average matrix permeability is 0.128×...The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m.The average matrix porosity of the reservoir is 5.5%,and the average matrix permeability is 0.128×10^(−3)μm^(2).In order to reveal the characteristics and efectiveness of ultra-deep fractures and their efects on reservoir properties and natural gas production,outcrops,cores,thin section,image logs and production testing data are used to investigate the efectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone,and the corresponding geological signifcance for oil and gas exploration and development are discussed.Tectonic fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear fractures.The former has a relatively high flling rate,while the latter is mostly unflled.Micro-fractures are usually grain-piercing-through cracks with width of 10-100 microns.In the planar view,the efective fractures are concentrated in the high part and wing zones of the long axis of the anticline,and along the vertical direction,they are mainly found in the tensile fracture zone above the neutral plane.The adjustment fracture zone has the strongest vertical extension abilities and high efectiveness,followed by the nearly EW longitudinal tensile fracture zone,and the netted fracture zone with multiple dip angles.The efectiveness of fracture is mainly controlled by fracture aperture and flling degrees.Efective fractures can increase reservoir permeability by 1-2 orders of magnitude.The higher part of the anticline is associated with high tectonic fracture permeability,which control enrichment and high production of natural gas.The netted vertical open fractures efectively communicate with pores and throats of the reservoir matrix,which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.展开更多
The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite(VTM) ore were investigated using scanning electron microscopy(SEM), nitrogen absorption measurements, par...The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite(VTM) ore were investigated using scanning electron microscopy(SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction(XRD) analysis, Fourier transform infrared(FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves' selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics.展开更多
The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)comp...The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.展开更多
Here,we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a metasurface.The geometrical dimensions of the proposed metasurface have been numerically opt...Here,we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a metasurface.The geometrical dimensions of the proposed metasurface have been numerically optimized.The introduction of the metasurface allows exploitation of its robust resonance and superior impedance matching in low-frequency bands,thereby improving microwave absorption properties.The incorporation of the metasurface does not impact the wave transmission performance of the honeycomb core absorber at high-frequency band,thus preserving its high-frequency performance.This broadens the absorption range,leading to an expanded bandwidth.Simulation results reveal that the composite absorber(CA)exhibits strong absorption performance with an incident angle stability up to 45°for both transverse electric(TE)and transverse magnetic(TM)modes.The absorption mechanism of the CA has been investigated by using an equivalent circuit model and electromagnetic field analysis.A prototype was designed,fabricated,and tested to validate the proposed method.Both simulation and measurement results demonstrate that the prototype can achieve an average absorption rate exceeding 90%across a 1.0-18.0 GHz range.This study introduces an innovative technique for creating microwave absorbers for low-frequency wideband applications.展开更多
基金This work was supported by the National Key Research and Development Project(No.2019YFC0605501)the National Science and Technology Major Project(2016ZX05003001).
文摘The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m.The average matrix porosity of the reservoir is 5.5%,and the average matrix permeability is 0.128×10^(−3)μm^(2).In order to reveal the characteristics and efectiveness of ultra-deep fractures and their efects on reservoir properties and natural gas production,outcrops,cores,thin section,image logs and production testing data are used to investigate the efectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone,and the corresponding geological signifcance for oil and gas exploration and development are discussed.Tectonic fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear fractures.The former has a relatively high flling rate,while the latter is mostly unflled.Micro-fractures are usually grain-piercing-through cracks with width of 10-100 microns.In the planar view,the efective fractures are concentrated in the high part and wing zones of the long axis of the anticline,and along the vertical direction,they are mainly found in the tensile fracture zone above the neutral plane.The adjustment fracture zone has the strongest vertical extension abilities and high efectiveness,followed by the nearly EW longitudinal tensile fracture zone,and the netted fracture zone with multiple dip angles.The efectiveness of fracture is mainly controlled by fracture aperture and flling degrees.Efective fractures can increase reservoir permeability by 1-2 orders of magnitude.The higher part of the anticline is associated with high tectonic fracture permeability,which control enrichment and high production of natural gas.The netted vertical open fractures efectively communicate with pores and throats of the reservoir matrix,which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.
基金financially supported by the National Natural Science Foundation of China (Nos. 51574082 and 51874077)the Fundamental Research Funds for the Central University of China (Nos. N150202001 and N172507012)
文摘The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite(VTM) ore were investigated using scanning electron microscopy(SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction(XRD) analysis, Fourier transform infrared(FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves' selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics.
基金supported by the National Natural Science Foundation of China (Nos. 51772130, 51972145)。
文摘The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.
基金supported by the National Natural Science Foundation of China(Nos.52073010 and 52373259)。
文摘Here,we present a unique method to enhance the low-frequency absorption performance of a honeycomb absorber by integrating a metasurface.The geometrical dimensions of the proposed metasurface have been numerically optimized.The introduction of the metasurface allows exploitation of its robust resonance and superior impedance matching in low-frequency bands,thereby improving microwave absorption properties.The incorporation of the metasurface does not impact the wave transmission performance of the honeycomb core absorber at high-frequency band,thus preserving its high-frequency performance.This broadens the absorption range,leading to an expanded bandwidth.Simulation results reveal that the composite absorber(CA)exhibits strong absorption performance with an incident angle stability up to 45°for both transverse electric(TE)and transverse magnetic(TM)modes.The absorption mechanism of the CA has been investigated by using an equivalent circuit model and electromagnetic field analysis.A prototype was designed,fabricated,and tested to validate the proposed method.Both simulation and measurement results demonstrate that the prototype can achieve an average absorption rate exceeding 90%across a 1.0-18.0 GHz range.This study introduces an innovative technique for creating microwave absorbers for low-frequency wideband applications.
