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A Single Well Production Forecasting Model of Reservoir Based on Conditional Generative Adversarial Net
Can HUANG, Leng TIAN, Heng-li WANG, Jia-xin WANG, Li-li JIANG
Chinese Journal of Computational Physics    2022, 39 (4): 465-478.   DOI: 10.19596/j.cnki.1001-246x.8480
Abstract200)   HTML14)    PDF (11595KB)(1169)      

To address overfitting problem of production forecast model in machine learning and improve accuracy of production forecast in actual oil field, a model for single well production forecasting of reservoir based on Conditional Generative Adversarial Net(CGAN) was proposed. The model hybridizes two types of basic neural network structures, i.e., long short-term memory network and fully connected network, to construct a generative model and a discriminant model. The generative model takes production influencing factors as conditions to generate the forecasting production data. It defines a logarithmic loss function as a residual between predicted and real data, to improve comprehensively the generalization ability of the model. Bayesian hyperparameter optimization algorithm was used to optimize the model structure through game training of CGAN. With numerical simulation software Eclipse, single well production database with same well pattern under different geological and production conditions was established to train CGAN, which can be used to predict rapidly single well production of reservoir by taking geological and production factors as condition input of the model. Experimental results show that compared with prediction results of models FCNN, RF, and LSTM, mean absolute percentage error of CGAN model on the test set is increased by 2.59%, 0.81%, and 1.72%. The overfitting ratio is the smallest(1.027). It indicates that CGAN reduces overfitting degree of the machine-learning-based production forecast model, and improves generalization ability and accuracy of the model as well. This verifies superiority of the algorithm, which is of great significance to guide efficient development of oilfields and ensures security of national energy strategy.

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Near-field Ferromagnetic Object Detection Based on 3D Magnetic Imaging
LI Jian, JIN Chunxing, ZHANG Yu, HUANG Xinjing
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2020, 37 (1): 88-96.   DOI: 10.19596/j.cnki.1001-246x.7966
Abstract348)   HTML1)    PDF (15631KB)(1096)      
We propose a method for three-dimensional inversion imaging of unknown magnetic sources in near-field conditions. Considering that most magnetic sources are not only magnetized with background magnetic field, but also have strong remanence, we convert magnetic field on observation surface into magnetic field vector anomaly modulus, and establish objective function to optimize solution to get the best match for magnetic field characteristics. Simulations and experiments show that the method eliminates effectively influence of residual magnetism on inversion results, and realizes imaging of magnetic susceptibility distribution of multiple magnetic sources in near field. It shows that the proposed method can be used to detect position and shape of unknown magnetic body.
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Simultaneous Synthesis of Heat Exchanger Network by Random Walk Algorithm with Compulsive Evolution Based on Trilevel Protection Strategy
LI Jian, CUI Guomin, CHEN Jiaxing, XIAO Yuan
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2019, 36 (1): 69-79.   DOI: 10.19596/j.cnki.1001-246x.7814
Abstract420)   HTML0)    PDF (5292KB)(1781)      
To avoid the problem of being disturbed by stochastic acceptance of imperfect solution for evolution process of individual optimal solution existing in optimization of heat exchanger network by random walk algorithm with compulsive evolution, an improved RWCE based on trilevel protection strategy is proposed. Individuals in population are divided into three levels. The lower-level is optimized by basic RWCE to protect global search ability of individuals. The middle-level reads historical optimal solution of the lower-level's individuals, and optimized by RWCE with fine tuning to protect evolution process of each individual's optimal solution from disruption. All individuals in the upper-level are initialized by solution of the best individuals in the middle-level, and optimized by RWCE with automatic fine search to ensure that the best individuals are fully searched. Finally, result of the upper-level is passed to corresponding individual at the lower-level. Two cases are optimized by using the algorithm,and results are better than those in literature. Evolution process of individual optimal solution is protected while accepting imperfect solution, therefore, both global search ability and local search ability are realized.
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Standards for Grid and Zone in Simulation of Flow in 5×5 Pins Assembly
LIU Jian, CHEN Jun, LI Jian, WANG Shiqing
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2018, 35 (4): 451-457.   DOI: 10.19596/j.cnki.1001-246x.7660
Abstract351)   HTML1)    PDF (4680KB)(1142)      
To obtain reasonable scales and grid requirements of computational zone, water flow in 5×5 fuel pins assembly was simulated adopting incompressible N-S equations, standard k-ε turbulent model and SIMPLE algorithm. By comparing pressure drop, velocity and its vertical component at different planes perpendicular to fuel pins, with relative error smaller than 5%, conclusions were obtained. Length of inlet part and outlet part of computational domain should be about 2.0 times and 2.3-2.8 times of space between two spacer. Polyhedral mesh should be adopted and its scale should be smaller than 0.35 mm in zone between spacer as smooth pin zone adopt structured grid with 0.3 mm-0.5 mm dimension.
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Effects of Temperature on Electromagnetic Parameters of Composite Formed with Line-Shaped Metallic Particles
XU Jian, LI Jiangnan, WU Jie, LIANG Feng, CHEN Jiangwei
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2017, 34 (2): 214-220.  
Abstract321)   HTML0)    PDF (2401KB)(1091)      
It is shown that various closed circuits formed by line-shaped metallic particles in composite induce great permeability. Effect of temperature on magnetic response is weak. Based upon effective medium theory,electric and magnetic response of composites containing line-shaped tungsten particles are addressed. Microwave absorbing composites are designed and optimized, which may be applied in high temperature circumstances.
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Thyristor Latching Current and Maintain Current
TAN Wei, LI Jianqing
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2015, 32 (6): 729-734.  
Abstract1025)      PDF (1318KB)(1661)      
Thyristor latching current and maintaining current have important effects on its working state. With thyristor conduction characteristics latching current is derived from carrier density; Based on current gain of NPN transistor, maintaining current is obtained. Compared with simulation results of Sentaurus TCAD software, calculated results have good agreement. It shows correctness of the formula.
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A Z-transform Implementation of Higher-order Perfectly Matched Layer
FENG Naixing, LI Jianxiong
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2012, 29 (2): 271-276.  
Abstract396)      PDF (291KB)(1163)      
With stretched coordinate perfectly matched layer (SC-PML) formulations and Z-transform method,an efficient and unsplit-field implementation of higher-order PML scheme with more than one pole is proposed which truncates finite-difference time-domain (FDTD) lattices.The higher-order PML has advantages of both conventional PML and complex frequency shifted PML (CFS-PML) in terms of absorbing performances.A numerical validation of the proposed formulations is provided through a 2D TE-polarized electromagnetic wave interaction with an infinitely long perfectly electric conductor (PEC) sheet with finite width.It is shown that the proposed PML formulations with higher-order scheme are efficient in terms of attenuating low-frequency propagating waves and evanescent waves and reducing late-time reflections.It has better absorbing performances than conventional SC-PML and convolutional PML (CPML) with CFS scheme.
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An Improved ICCG Method for Large Scale Sparse Linear Equations
ZHANG Yongjie, SUN Qin, LI Jianghai
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2007, 24 (5): 581-584.  
Abstract308)      PDF (178KB)(1421)      
Based on incomplete Cholesky decomposition with two thresholds,we propose an improved incomplete Cholesky conjugate gradient (ICCG) method with diagonal elements modification.It ensures accurate and efficient decomposition and solution of large scale sparse linear equations. The method shows advantage in computing time and storage requirment.It is applicable to solve the systems of linear equations from FEM finite element method.
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Simulation of an Inverse Zimmerman Wing at Low Reynolds Numbers
LI Jianhua, LI Feng
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2007, 24 (1): 49-53.  
Abstract235)      PDF (415KB)(1232)      
Unsteady incompressible Navier-Stokes equations are solved with a pressure correction method.A series of numerical calculations are conducted for Low-Reynolds-Number aerodynamics of an inverse Zimmerman wing.It shows that a pair of strong leading-edge vortex exist beyond the wing.They have strong effect on the inverse Zimmerman wing aerodynamics and offer high nonlinear lift and large stall attack angle.Interaction between the leading-edge vortexes results in unsteady and asymmetry phenomenon of the wing.The inverse Zimmerman wing shows a better longitudinal stability and flow-field stability.
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Constructing a Class of Orthogonal-reinforced Hierarchical Hexahedra Vector FE
LI Jiang-hai, SUN Qin
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    2006, 23 (1): 32-36.  
Abstract360)      PDF (203KB)(1078)      
By the merits of hierarchial orthogonal polynomial, a method of constructing a class of orthogonal-reinforced hierarchical hexahedra vector finite elements(ORHHVFE) to achieve a better condition of systematic matrix is presented, and the basis functions of hierarchical hexahedra vector finite elements(HHVFE) at the angle of conforming elemental systematic matrices are studied in detail. Numerical tests of the ORHHVFE constructed using 1-st Legendre polynomials based on the above method and the other HHVFE were carried out and compared. The results show that the ORHHVFE has the same numerical precision with the HHVFE, and the conditions of systematic matrices by the ORHHVFE are improved largely.
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COMPUTER SIMULATION IN THE FORMATION PROCEDURE OF TWO DIMENSIONAL MOULDS
Li Jianshi, Chen Tianjian, Mei Guangqian
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    1997, 14 (S1): 605-607.  
Abstract198)      PDF (132KB)(1004)      
It discusses a mechanical model as well as its contact-searching method and dynamic explicit algorithm used for formation procedure of two dimensional moulds.A specific example of an electrical mould for applicaiton interest is also presented.
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THE SYNTHEIZED MODEL AND COMPUTER SIMULATION ABOUT STATIC-DYNAMIC-ELECTRICAL CONTACT PROCESS OF MICROSWITCH
Li Jianshi, Chen Tianjian, Yang Zhonghui
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    1996, 13 (4): 433-438.  
Abstract283)      PDF (233KB)(1113)      
In this paper,taking microswitch as type mechanism of openable-closed electromechanical components,on basis of constructing it's finite element model of the quick acting mechanism's static-dynamic process and contact system's electrical contact process.Furthermore,we regard static-dynamic and electrical contact process as a whole by using dynamic model combining static-dynamic and electrical contact model as whole.We have constructed synthesized,have taken AK# microswitch as example,and have given synthesized example of computer simulation.
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THE ACCELERATION METHOD FOR NUMERICAL INVERSION OF LAPLACE TRANSFORMS
Wang Qiu, Li Jianliang
CHINESE JOURNAL OF COMPUTATIONAL PHYSICS    1990, 7 (4): 461-466.  
Abstract258)      PDF (314KB)(929)      
Based on the computing of oscillatory integral. A class of recurrence serices for approximating inversion Laplace transform, is suggested with the acceleration methods for every serice. Then the extrapolation method is applied to these serie's sequence.
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