An abrasive water jet(AWJ)is commonly used to develop deep geothermal resources,such as drilling in hot dry rock(HDR).The influence of rock mineral properties,such as mineral types,mineral contents,and grain size,on t...An abrasive water jet(AWJ)is commonly used to develop deep geothermal resources,such as drilling in hot dry rock(HDR).The influence of rock mineral properties,such as mineral types,mineral contents,and grain size,on the formation of perforation by AWJ is unclear yet.In this study,we investigate AWJ impacts on three types of granite samples with different mineral fractions using a polarizing microscope and scanning electron microscope(SEM).The results show that when the grain size is doubled,the perforation depth increases by 16.22%under the same type of structure and properties.In general,fractures are more likely to be created at the position of rough surfaces caused by abrasive impact,and the form of fractures is determined by the mineral type.In addition,microstructure analysis shows that transgranular fractures typically pass through large feldspar particles and quartz removal occurs along mineral boundaries.The longitudinal extension of perforation depends mainly on the strong kinetic energy of the jet,while the lateral extension is controlled by the backflow.The results contribute to a better understanding of the process involved in the breaking of hard rock by abrasive jets during deep geothermal drilling.展开更多
Imaging scenes with a high dynamic range(HDR)of light intensities is critical for applications such as biomedical imaging,astronomical observation,and industrial automation,where accurate detection of both bright and ...Imaging scenes with a high dynamic range(HDR)of light intensities is critical for applications such as biomedical imaging,astronomical observation,and industrial automation,where accurate detection of both bright and dark regions is essential for precise analysis and decision-making.In this paper,we propose an HDR imaging approach harnessing optical forward scattering effect that breaks the limitations of image processing type.Our approach integrates a nonlinear deconvolution method based on speckle background noise estimation,along with Cross-correlation and Laplacian pyramid fusion method,to improve imaging precision and adaptability.By utilizing a digital micromirror device and a scattering diffuser,we develop a proof-of-concept experimental system,validating the effectiveness of reconstruction of faint details in HDR scenes.This method achieves dynamic range expansion from a 130.01 dB HDR scene using a detector with an 88.5 dB dynamic range,achieving a 119-fold intensity difference.Our work demonstrates a promising new solution for HDR imaging in demanding lighting environments,which could expand the scope of photoelectronic imaging application.展开更多
Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hyd...Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hydraulic fracturing,primarily controlled by in situ stress,fail to connect directionally with the target well.This study proposes a novel stimulation method,i.e.radial borehole fracturing,which shows great potential for guiding the directional propagation of fractures.The fracture initiation and propagation behaviors of high-temperature granite under radial borehole fracturing are investigated and compared with those of conventional fracturing.Three-dimensional morphological scanning and reinjection tests are used to quantitatively evaluate fracturing performance.Additionally,the influences of key parameters,including rock temperature,in situ stress,injection rate,fluid viscosity,azimuth of the radial borehole,and the number of radial boreholes on the fracture morphology and breakdown pressure are investigated.The results show that radial borehole fracturing can effectively guide the initiation and propagation of fractures along the radial borehole.The breakdown pressure of radial borehole fracturing can be reduced by 14.1%–43.7%compared to conventional fracturing.A higher fluid-rock temperature difference reduces the directional propagation range of fractures guided by the radial borehole.Increases in the vertical density of radial boreholes,injection rate,and fluid viscosity enhance the guiding ability of radial boreholes.Furthermore,there is a competitive relationship between in situ stress and the azimuth of radial boreholes in controlling fracture propagation.This research provides a viable alternative for the directional connection of injection-production wells in HDR reservoirs.展开更多
基金supported by the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20233326)the Chongqing Science Fund for Distinguished Young Scholars(Grant No.CSTB2022NSCQJQX0028)the National Natural Science Foundation of China(Grant Nos.U23A20597,52274112).
文摘An abrasive water jet(AWJ)is commonly used to develop deep geothermal resources,such as drilling in hot dry rock(HDR).The influence of rock mineral properties,such as mineral types,mineral contents,and grain size,on the formation of perforation by AWJ is unclear yet.In this study,we investigate AWJ impacts on three types of granite samples with different mineral fractions using a polarizing microscope and scanning electron microscope(SEM).The results show that when the grain size is doubled,the perforation depth increases by 16.22%under the same type of structure and properties.In general,fractures are more likely to be created at the position of rough surfaces caused by abrasive impact,and the form of fractures is determined by the mineral type.In addition,microstructure analysis shows that transgranular fractures typically pass through large feldspar particles and quartz removal occurs along mineral boundaries.The longitudinal extension of perforation depends mainly on the strong kinetic energy of the jet,while the lateral extension is controlled by the backflow.The results contribute to a better understanding of the process involved in the breaking of hard rock by abrasive jets during deep geothermal drilling.
基金supported by National Natural Science Foundation of China(NSFC)(62105254,62205259,62375212,and 62405231)Fundamental Research Funds for the Central Universities(XJSJ24028,XJS222202,and YJSJ25010)+1 种基金Science Fund for Distinguished Young Scholars of Shaanxi Province(2024JC-JCQN-60)National Key Laboratory of Space Target Awareness,and Innovation Fund of Xidian University.
文摘Imaging scenes with a high dynamic range(HDR)of light intensities is critical for applications such as biomedical imaging,astronomical observation,and industrial automation,where accurate detection of both bright and dark regions is essential for precise analysis and decision-making.In this paper,we propose an HDR imaging approach harnessing optical forward scattering effect that breaks the limitations of image processing type.Our approach integrates a nonlinear deconvolution method based on speckle background noise estimation,along with Cross-correlation and Laplacian pyramid fusion method,to improve imaging precision and adaptability.By utilizing a digital micromirror device and a scattering diffuser,we develop a proof-of-concept experimental system,validating the effectiveness of reconstruction of faint details in HDR scenes.This method achieves dynamic range expansion from a 130.01 dB HDR scene using a detector with an 88.5 dB dynamic range,achieving a 119-fold intensity difference.Our work demonstrates a promising new solution for HDR imaging in demanding lighting environments,which could expand the scope of photoelectronic imaging application.
基金supported by the National Science Fund of China for Major International(Regional)Joint Research Project(Grant No.52020105001)the National Natural Science Foundation of China(Grant Nos.52304053 and 52204019).
文摘Creating complex and interconnected fracture networks between injection and production wells is crucial for exploiting hot dry rock(HDR)geothermal energy.However,the simple planar fractures created by conventional hydraulic fracturing,primarily controlled by in situ stress,fail to connect directionally with the target well.This study proposes a novel stimulation method,i.e.radial borehole fracturing,which shows great potential for guiding the directional propagation of fractures.The fracture initiation and propagation behaviors of high-temperature granite under radial borehole fracturing are investigated and compared with those of conventional fracturing.Three-dimensional morphological scanning and reinjection tests are used to quantitatively evaluate fracturing performance.Additionally,the influences of key parameters,including rock temperature,in situ stress,injection rate,fluid viscosity,azimuth of the radial borehole,and the number of radial boreholes on the fracture morphology and breakdown pressure are investigated.The results show that radial borehole fracturing can effectively guide the initiation and propagation of fractures along the radial borehole.The breakdown pressure of radial borehole fracturing can be reduced by 14.1%–43.7%compared to conventional fracturing.A higher fluid-rock temperature difference reduces the directional propagation range of fractures guided by the radial borehole.Increases in the vertical density of radial boreholes,injection rate,and fluid viscosity enhance the guiding ability of radial boreholes.Furthermore,there is a competitive relationship between in situ stress and the azimuth of radial boreholes in controlling fracture propagation.This research provides a viable alternative for the directional connection of injection-production wells in HDR reservoirs.
