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89 results on '"Cheng, Lifang"'

52. The Application of Reverse-Time Migration in the Z Area of PRM Basin

Author

Cheng Lifang, Yanchun Wang, Xi Zheng, He Run, and Fang Yuan

Subjects
010504 meteorology & atmospheric sciences, Seismic migration, Structural basin, 010502 geochemistry & geophysics, Fault (power engineering), 01 natural sciences, PEARL (programming language), Shadow, Geotechnical engineering, computer, Algorithm, Geology, 0105 earth and related environmental sciences, computer.programming_language
Abstract

Reverse time migration (RTM) is an accurate migration method, which is based on two-way wave equation, eliminates angle limitation, and can be capable for imaging of reverse branch and multiple. In the development of an oilfield in Pearl River Mouth (PRM) Basin, RTM has been applied to solve the problems of fault shadow and structure in distinction and the drilling has proven that the RTM result is reliable. This paper introduces the theory of RTM and emphatically discusses parameter selection. The results of RTM showed that it had advantages in resolving fault shadow and the imaging of steep dip structure, and could be utilized in the oilfield.

Published
2016

53. An application of seismic attributes analysis for mapping of gas bearing sand zones in the sawan gas field, Pakistan

Author

Cheng Lifang, Fang Yuan, Liu Xueqing, Perveiz Khalid, Wang Yanchun, and Tahir Azeem

Subjects
Bearing (mechanical), 010504 meteorology & atmospheric sciences, Window (geology), Geology, Regression analysis, Soil science, Building and Construction, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, Instantaneous phase, law.invention, Natural gas field, Geophysics, law, Linear regression, Geotechnical engineering, Statistical analysis, 0105 earth and related environmental sciences
Abstract

Sandstone intervals of the Lower Goru Formation of the Cretaceous age are proven reservoir intervals in the middle Indus Basin, Pakistan. However, based on seismic data interpretation, it is difficult to differentiate payable gas sand from non-payable gas sand. Various types of post-stacks seismic attributes are extracted and analyzed to differentiate payable gas sand from non-payable. The analysis reveals that average instantaneous frequency, peak spectral frequency, average instantaneous phase and sweetness seem to be more effective attributes along with energy half time. Sweetness attribute map shows two sweet spot below the targeted window which indicate to the presence of gas play. Statistical analysis is also carried out to find the associations between seismic attributes and thickness of gas layer values. Cross plots of these attributes were quantified through regression analysis. A good correlation with regression coefficient (R2) > 0.78 is found between seismic attributes and gas layer thickness except average instantaneous phase attribute, which lays the foundation for predicting the thickness of gas reservoir.

Published
2015

70. Neural Mechanism of Creative Cognitive Process Influenced by Emotion

Author

LI Jingjing, HU Weiping, Cheng Lifang, Wang Botao, Zhou Huan, and Duan Haijun

Subjects
media_common.quotation_subject, Cognition, Creativity, Psychology, General Economics, Econometrics and Finance, Mechanism (sociology), media_common, Cognitive psychology
Published
2015

84. An image interpolation-based approach to the detection of small moving target.

Author

Deng, He and Cheng, Lifang

Subjects
IMAGE analysis, INTERPOLATION, DETECTORS, COMPUTER user identification, CAMERAS, COMPUTER vision, APPLICATION software
Abstract

Abstract: The problems of detection, identification and tracking of moving target under the condition of moving camera are quite difficult in the application of computer vision. This paper proposes two different methods to the detection of moving target in the light of the size of the object. One approach integrates the image-interpolation technique and the active contour model, the other unites the image-interpolation technique, the modified local entropy algorithm and the region growing skill. The introduction of the image-interpolation technique is to estimate the global motion, i.e. background motion. The active contour model or the modified local entropy algorithm and region growing skill act upon the difference image, and then detect the moving target. It is demonstrated the reasonableness and efficiency of two detection approaches through experiments. [Copyright &y& Elsevier]

Published
2011
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85. Local reverse entropy and its application in small targets detection.

Author

Deng, He, Liu, Qingtang, and Cheng, Lifang

Subjects
ALGORITHMS, SIGNAL-to-noise ratio, PROBLEM solving, ENTROPY, QUANTITATIVE research, QUALITATIVE research
Abstract

Abstract: The detection of small targets that submerges in the homogeneous image background is a difficult problem in the design of small targets detection algorithm. The concept of local reverse entropy combining the concepts of local ntropy with reverse entropy is proposed in this paper, which is to solve that problem by enhancing small targets. The norms of local signal-to-background ratio and elapsed time are used to demonstrate the performance of local reverse ntropy map. Both quantitative analysis and qualitative comparison confirm the validity and efficiency of the resented approach. [Copyright &y& Elsevier]

Published
2011
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89. Enhanced electrical properties of Pb(Zr0.80Ti0.20)O3 thick films prepared by a modified sol–gel technique

Author

Pu, Zhaohui, Wu, Jiagang, Yu, Xudong, Xu, Peng, Cheng, Lifang, Xiao, Dingquan, and zhu, Jianguo

Subjects
*COLLOIDS, *SPUTTERING (Physics), *YIELD surfaces, *THIN films
Abstract

Abstract: Ferroelectric Pb(Zr0.80Ti0.20)O3 thick films (5.0 μm) were grown on Pt/Ti/SiO2/Si substrates by a modified sol–gel technique. In this process, PZT nanopowders were prepared via sol–gel, and then these powders were dispersed in a precursor sol to form a slurry. Slurry and PZT precursor solution were spin-coated alternately to form uniform and crack-free thick films. The microstructure and electrical properties of the PZT thick films were investigated. The results in this work show that the PZT thick films possess typical polycrystalline perovskite structures, good pyroelectric coefficient (8.0×10−8C/cm2 K), high remnant polarization (30 μC/cm2), and low coercive field (50 kV/cm). [Copyright &y& Elsevier]

Published
2008
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