In oil and gas exploitation,cluster well technology can significantly reduce costs and improve efficiency.An effective adjacent well detection method can greatly reduce the risk of collision between adjacent wells.Thi...In oil and gas exploitation,cluster well technology can significantly reduce costs and improve efficiency.An effective adjacent well detection method can greatly reduce the risk of collision between adjacent wells.This study proposes a method to invert the 3D trajectory of an adjacent well using a scattered P-wave obtained by borehole azimuthal acoustic reflection imaging.After obtaining the scattered P-wave from the raw data of the target well using the wave field separation technology,the waveform data in an imaging profile can be obtained by the downhole acoustic directional reception technology.Migration imaging technology is then used to obtain the image of the formation in the imaging profile.Subsequently,by analyzing the images of the formation in the imaging profile of the different azimuths,the well spacing and azimuth of the target well can be determined.Finally,the 3D trajectory of the target well can be obtained by solving the inversion equation.This method was validated by processing the field data from a deviated well in a deep formation.The comparison of the inversion and actual trajectories of the target well demonstrated that the maximum deviation of the inversion trajectory is 0.9 m in the north-south direction,0.78 m in the east-west direction,1.45 m in the well spacing,and 2.48°in the azimuth.The field data inversion result demonstrated that the method can effectively use the azimuth reflection acoustic data to invert the 3D trajectory of an adjacent well,which indicates that the borehole azimuthal acoustic reflection imaging technology has great potential within the context of adjacent well detection.展开更多
Background Adjacent segment disease （ASD） is common after cervical fusion.The aim of this study was to evaluate the risk factors for ASD on X-ray and magnetic resonance imaging （MRI）.Methods Patients included in t...Background Adjacent segment disease （ASD） is common after cervical fusion.The aim of this study was to evaluate the risk factors for ASD on X-ray and magnetic resonance imaging （MRI）.Methods Patients included in this study had received revision surgeries after developing symptomatic ASD following anterior decompression and fusion.A control group that had not developed ASD was matched 1：1 by follow-up time and fusion segments.Plate-to-disc distances （PDDs）,developmental cervical canal stenosis on X-ray,cervical disc degeneration grading,and cervical disc bulge impingements on preoperative MRI were measured and compared between the ASD group and the control group.Results Thirty-four patients with complete radiographic data were included in the ASD group.The causative segments of ASD included nine cases of C3-4,18 cases of C4-5,three cases of C5-6,and four cases of C6-7.The ASD occurred at the upper adjacent segments in 26 patients and at the lower adjacent segments in eight patients.PDD distributions were similar between the ASD group and the control group.Developmental cervical canal stenosis was a risk factor for ASD,with an odd ratio value of 2.88.Preoperative cervical disc degenerations on MRI were similar between the ASD group and the control group.In the upper-level ASD group,the disc bulge impingement was （19.7±9.7）％,which was significantly higher than that of the control group of （11.8±4.8）％.Conclusions ASD was more likely to develop above the index level of fusion.Developmental cervical canal stenosis and greater disc bulge impingement may be risk factors for the development of ASD.展开更多
The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A waters...The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A watershed transformation technique is then employes. This includes: gradient of the classified image, dividing the image into markers, checking the Marker Image to see if it has zero points (watershed lines). The watershed lines are then deleted in the Marker Image created by watershed algorithm. A Region Adjacency Graph (RAG) and Region Adjacency Boundary (RAB) are created between two regions from Marker Image. Finally region merging is done according to region average intensity and two edge strengths (T1, T2). The approach of the authors is tested on remote sensing and brain MR medical images. The final segmentation result is one closed boundary per actual region in the image.展开更多
基金supported by the National Natural Science Foundation of China(grant numbers 12274465,42174218)the Strategic Cooperation Technology Projects of CNPC and CUPB(grant numberZLZX2020-02).
文摘In oil and gas exploitation,cluster well technology can significantly reduce costs and improve efficiency.An effective adjacent well detection method can greatly reduce the risk of collision between adjacent wells.This study proposes a method to invert the 3D trajectory of an adjacent well using a scattered P-wave obtained by borehole azimuthal acoustic reflection imaging.After obtaining the scattered P-wave from the raw data of the target well using the wave field separation technology,the waveform data in an imaging profile can be obtained by the downhole acoustic directional reception technology.Migration imaging technology is then used to obtain the image of the formation in the imaging profile.Subsequently,by analyzing the images of the formation in the imaging profile of the different azimuths,the well spacing and azimuth of the target well can be determined.Finally,the 3D trajectory of the target well can be obtained by solving the inversion equation.This method was validated by processing the field data from a deviated well in a deep formation.The comparison of the inversion and actual trajectories of the target well demonstrated that the maximum deviation of the inversion trajectory is 0.9 m in the north-south direction,0.78 m in the east-west direction,1.45 m in the well spacing,and 2.48°in the azimuth.The field data inversion result demonstrated that the method can effectively use the azimuth reflection acoustic data to invert the 3D trajectory of an adjacent well,which indicates that the borehole azimuthal acoustic reflection imaging technology has great potential within the context of adjacent well detection.
文摘Background Adjacent segment disease （ASD） is common after cervical fusion.The aim of this study was to evaluate the risk factors for ASD on X-ray and magnetic resonance imaging （MRI）.Methods Patients included in this study had received revision surgeries after developing symptomatic ASD following anterior decompression and fusion.A control group that had not developed ASD was matched 1：1 by follow-up time and fusion segments.Plate-to-disc distances （PDDs）,developmental cervical canal stenosis on X-ray,cervical disc degeneration grading,and cervical disc bulge impingements on preoperative MRI were measured and compared between the ASD group and the control group.Results Thirty-four patients with complete radiographic data were included in the ASD group.The causative segments of ASD included nine cases of C3-4,18 cases of C4-5,three cases of C5-6,and four cases of C6-7.The ASD occurred at the upper adjacent segments in 26 patients and at the lower adjacent segments in eight patients.PDD distributions were similar between the ASD group and the control group.Developmental cervical canal stenosis was a risk factor for ASD,with an odd ratio value of 2.88.Preoperative cervical disc degenerations on MRI were similar between the ASD group and the control group.In the upper-level ASD group,the disc bulge impingement was （19.7±9.7）％,which was significantly higher than that of the control group of （11.8±4.8）％.Conclusions ASD was more likely to develop above the index level of fusion.Developmental cervical canal stenosis and greater disc bulge impingement may be risk factors for the development of ASD.
文摘The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A watershed transformation technique is then employes. This includes: gradient of the classified image, dividing the image into markers, checking the Marker Image to see if it has zero points (watershed lines). The watershed lines are then deleted in the Marker Image created by watershed algorithm. A Region Adjacency Graph (RAG) and Region Adjacency Boundary (RAB) are created between two regions from Marker Image. Finally region merging is done according to region average intensity and two edge strengths (T1, T2). The approach of the authors is tested on remote sensing and brain MR medical images. The final segmentation result is one closed boundary per actual region in the image.
