Ccteg Xian Research Institute

Fengcheng, China

Ccteg Xian Research Institute

Fengcheng, China
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Zhu W.,Yangtze University | Zhao L.,Tongji University | Shan R.,CCTEG Xian Research Institute
Geophysics | Year: 2017

We have developed a dynamic stress-strain simulation methodology to compute effective elasticity on digital rocks in a wide range of frequency based on the rotated staggered grid finite-difference method. The primary advantage of this simulator lies in characterizing the anisotropic behavior of complex porous rocks by setting specified boundary conditions along specified directions: The edges perpendicular to the propagating wave are applied with a strain boundary condition, and the edges parallel to the propagating wave are applied with a periodic boundary condition. The accuracy of the simulator is validated by comparing the simulating results in microinhomogeneous porous media containing randomly distributed inclusions and aligned oriented cracks, with that obtained by effective medium theories of self-consistent approximation in isotropic and anisotropic domains. This dynamic simulator can successfully capture anisotropic magnitude of rocks containing needle-like inclusions with different degrees of alignment. For real digital rock saturated with viscoelastic fluids, it is able to predict the dependence of velocities and attenuating factors on the frequency. We found that the magnitude of dispersion increases with the increase of pore fluid viscosity. Therefore, this method offers a robust and effective tool to compute effective elastic properties and anisotropy for real complex porous rocks. © 2017 Society of Exploration Geophysicists.

Yu Y.-X.,Xi'an University of Science and Technology | Wang B.-Q.,CCTEG Xian Research Institute
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2015

To provide reference for design and construction of sidewall and floor, sidewall was regarded as a half infinite load-bearing beam and its soft and weak floor rock mass was simplified to a continuous elastic foundation, according to sidewall stratum and its mechanical characteristics of the tunnel. By setting up Winkler elastic foundation beam model of the sidewall under high bearing pressure, the distribution law of deflection, rotation, bending moment and shear force of sidewall on any interface of rock mass was analyzed and the relations between the limit equilibrium zone width and tunnel buried depth, the elastic characteristic value of floor rock, overburden rock mass density as well as stress concentration factor, elastic zone width and the shear strength of rock mass on elastic-plastic interface of the sidewall were derived. The maximum plastic failure depth of the weak floor under the squeeze of sidewall was discussed after the limit equilibrium zone width was certain. The result shows that the maximum plastic failure depth is closely related to the tunnel buried depth, stress concentration factor, the limit equilibrium zone width of the tunnel wall, the volume-weight of overburden rock mass and floor, the cohesion and internal friction angle of the floor. ©, 2015, Xi'an Highway University. All right reserved.

Yang P.,Xi'an Jiaotong University | Yang P.,University of Texas at Austin | Gao J.,Xi'an Jiaotong University | Wang B.,CCTEG Xian Research Institute
Computers and Geosciences | Year: 2014

GPU has become a booming technology in reverse time migration (RTM) to perform the intensive computation. Compared with saving forward modeled wavefield on the disk, RTM via wavefield reconstruction using saved boundaries on device is a more efficient method because computation is much faster than CPU-GPU data transfer. In this paper, we introduce the effective boundary saving strategy in backward reconstruction for RTM. The minimum storage requirement for regular and staggered grid finite difference is determined for perfect reconstruction of the source wavefield. Particularly, we implement RTM using GPU programming, combining staggered finite difference scheme with convolutional perfectly matched layer (CPML) boundary condition. We demonstrate the validity of the proposed approach and CUDA codes with numerical example and imaging of benchmark models. © 2014 Elsevier Ltd.

Yang P.,Xi'an Jiaotong University | Gao J.,Xi'an Jiaotong University | Wang B.,CCTEG Xian Research Institute
Geophysics | Year: 2015

The graphics processing unit (GPU) has become a popular device for seismic imaging and inversion due to its superior speed-up performance. We implemented GPU-based fullwaveform inversion using the wavefield reconstruction strategy. Because computation on the GPU was much faster than CPU-GPU data communication, in our implementation, the boundaries of the forward modeling were saved on the device toaverttheissueofdatatransferbetweenthehostanddevice.We adopted the Clayton-Enquist absorbing boundary to maintain the efficiencyof theGPUcomputation.Ahybridnonlinear conjugate gradient algorithmcombinedwith the parallel reduction scheme was used to do computation in GPU blocks. The numerical results confirmed thevalidity of our implementation. © 2015 Society of Exploration Geophysicists.

Zhu W.,Yangtze University | Shan R.,Ccteg Xian Research Institute
Applied Geophysics | Year: 2016

Transmitted ultrasonic wave simulation (TUWS) in a digital core is one of the important elements of digital rock physics and is used to study wave propagation in porous cores and calculate equivalent velocity. When simulating wave propagates in a 3D digital core, two additional layers are attached to its two surfaces vertical to the wave-direction and one planar wave source and two receiver-arrays are properly installed. After source excitation, the two receivers then record incident and transmitted waves of the digital rock. Wave propagating velocity, which is the velocity of the digital core, is computed by the picked peak-time difference between the two recorded waves. To evaluate the accuracy of TUWS, a digital core is fully saturated with gas, oil, and water to calculate the corresponding velocities. The velocities increase with decreasing wave frequencies in the simulation frequency band, and this is considered to be the result of scattering. When the pore fluids are varied from gas to oil and finally to water, the velocity-variation characteristics between the different frequencies are similar, thereby approximately following the variation law of velocities obtained from linear elastic statics simulation (LESS), although their absolute values are different. However, LESS has been widely used. The results of this paper show that the transmission ultrasonic simulation has high relative precision. © 2016, Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.

Wang Y.-B.,CCTEG Xian Research Institute
Wutan Huatan Jisuan Jishu | Year: 2016

At present, the CSAMT study is based on the assumption of the line source is horizontal. However in undulating mountain areas, the line source can hardly be kept on horizon. For this case, the calculation formulas of rolling source and discusses the measuring field, apparent resistivity and phase with rolling are introduced in the forward modeling in this paper. The results show that the rolling source has strongly influence on the field data and the apparent resistivity and phase data of near-field, but a little influence on the transition-field data and far-field data. However the apparent resistivity and phase data of near-field also has much difference, so it is necessary to consider rolling source when it applied in near-field data.

Liu G.Q.,CCTEG Xian Research Institute
Advanced Materials Research | Year: 2014

Workflow is a key technology of process management and process control in PDM system. It introduce the definition of workflow and the workflow management model,and define standard process of all kinds of documents management graphically and task nodes of different business process, which include design flow and drawings change process. It makes the manageability enhanced, and improve the automatization and the efficiency of flow execution, realize the workflow management in the design of drilling rig. © (2014) Trans Tech Publications, Switzerland.

Hongwei T.,Ccteg Xian Research Institute | Wenxin H.,Ccteg Xian Research Institute
Open Civil Engineering Journal | Year: 2015

By summarizing the experiences of routine acquisition geometry designs, and using the 3D seismic survey data of a less explored region for instance, this paper put forward an acquisition geometry design method for less explored region plus the geological stratum calibration by reflection wave and time-depth conversion method. After drilling data and roadway data verification, the re-argumentation of acquisition geometry parameters for parameter determination and the forward modeling technique for geological stratum calibration and the stacking velocity time-depth conversion are proved to be very effective in improving the accuracy of seismic survey. © Hongwei and Wenxin; Licensee Bentham Open.

Yang G.,CCTEG xiAn Research Institute | Zhang W.,ChinaSoft International Technology Service LTD
2015 12th International Computer Conference on Wavelet Active Media Technology and Information Processing, ICCWAMTIP 2015 | Year: 2015

With the unprecedentedly development of Cloud Computing, the scale and quantity of the data center has been numerously increased, how to reduce the energy consumption of the data center servers are becoming the research hotspot of the related enterprises. Nowadays, virtual machine migration techniques has become the mainly method to solve the energy consumption of the data center. In this paper, we propose an optimized virtual machine migration technique which based on OpenStack Cloud platform, avoid invalid migration with the properly threshold and time sequence prediction technique so that can save the general energy consumption of the data center. © 2015 IEEE.

Yang G.,CCTEG xiAn Research Institute | Zhang W.,ChinaSoft International Technology Service LTD
2015 12th International Computer Conference on Wavelet Active Media Technology and Information Processing, ICCWAMTIP 2015 | Year: 2015

Along with the rapidly development of cloud computing and virtualization technology, the proper resource allocation or scheduling strategy is becoming more and more important. When the usage of the server is too low, meanwhile, the consumption of power is greater than the ability of providing services, this will lead to waste of physical resources. However, when the usage of the server is too high, will increase the consumption of the server, that will be a consequences of insufficient for other virtual machines' resources requirements, we can solve this problem by virtual machines migration so that can lower the server's overload and the increasing energy consumption. In this paper, we study the resource scheduling strategy under the OpenStack environment, analyze the Scheduler module and discuss its advantages and disadvantages when we use it to schedule the resources. © 2015 IEEE.

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