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Ma Z.,China University of Petroleum - Beijing | Ma Z.,LandOcean Energy Services Co. | Liu D.,China University of Petroleum - Beijing | Li H.,China University of Petroleum - Beijing | Gao X.,China University of Petroleum - Beijing
Advances in Applied Mathematics and Mechanics | Year: 2012

A novel, highly efficient and accurate adaptive higher-order finite element method (hp-FEM) is used to simulate a multi-frequency resistivity loggingwhile-drilling (LWD) tool response in a borehole environment. Presented in this study are the vector expression of Maxwell's equations, three kinds of boundary conditions, stability weak formulation of Maxwell's equations, and automatic hpadaptivity strategy. The new hp-FEM can select optimal refinement and calculation strategies based on the practical formation model and error estimation. Numerical experiments show that the new hp-FEM has an exponential convergence rate in terms of relative error in a user-prescribed quantity of interest against the degrees of freedom, which provides more accurate results than those obtained using the adaptive h-FEM. The numerical results illustrate the high efficiency and accuracy of the method at a given LWD tool structure and parameters in different physical models, which further confirm the accuracy of the results using the Hermes library (http://hpfem.org/hermes) with a multi-frequency resistivity LWD tool response in a borehole environment. © 2012 Global Science Press. Source

Liang F.-K.,China University of Geosciences | Yu X.-H.,China University of Geosciences | Li X.-P.,Petrochina | Zou M.,China University of Geosciences | Sun X.-C.,LandOcean Energy Services Co.
Geology in China | Year: 2011

As we all know, structure controls sedimentation, while sedimentation controls the reservoir. Lots of sedimentary facies maps, however, were compiled without considering the control of structural factors over the depositional system, which has led to the severe defect that sedimentary facies or/and palaeogeographic maps do not match with contemporaneous structural configuration. Growth faults are the main structural factors, whose activity would control the forming process of sedimentary strata. There were four types of growth faults developed in Shenxian depression in Cenozoic, constituting models of late activity, continuous activity, periodic activity and deep extension. In addiction, based on regional sediments provenance analysis, the authors probed into the control of growth faults over depositional systems, and found that subaqueous fans were developed in the south while deltas were developed in the north. The spread of the fronts of these two depositional systems were further controlled by growth faults, presenting characteristics that lobes spread along faults on the map while wedges overlap in the cross section. Source

He H.,Changan University | Yan Y.,LandOcean Energy Services Co. | Qu C.,Changan University | Fan Y.,Changan University
Mathematical Problems in Engineering | Year: 2014

Based on uncertainty measure theory, a stability classification and order-arranging model of surrounding rock was established. Considering the practical engineering geologic condition, 5 factors that influence surrounding rock stability were taken into account and uncertainty measure function was obtained based on the in situ data. In this model, uncertainty influence factors were analyzed quantitatively and qualitatively based on the real situation; the weight of index was given based on information entropy theory; surrounding rock stability level was judged based on credible degree recognition criterion; and surrounding rock was ordered based on order-arranging criterion. Furthermore, this model was employed to evaluate 5 sections surrounding rock in Dongshan tunnel of Huainan. The results show that uncertainty measure method is reasonable and can have significance for surrounding rock stability evaluation in the future. © 2014 Hujun He et al. Source

Gong B.,Peking University | Li J.,Peking University | Shan Y.,LandOcean Energy Services Co.
Society of Petroleum Engineers - International Petroleum Technology Conference 2013, IPTC 2013: Challenging Technology and Economic Limits to Meet the Global Energy Demand | Year: 2013

An integrated approach of fractured reservoir modeling is presented. First, the fracture density and azimuth distribution of the entire reservoir is mapped from seismic anisotropy analysis and image log calibrations. Then we apply a dynamic workflow to construct the discrete fracture model by connecting fracture elements laterally and vertically. A tetrahedral grid is then generated for detailed reservoir simulation that fully resolves the discrete fracture characterization. Finally the flow simulation is performed on an actual carbonate reservoir block in the Mideast. This study presents a systematic way of modeling and simulating fractured reservoirs. Copyright © 2013 International Petroleum Technology Conference. Source

Guo M.,LandOcean Energy Services Co. | Zhao Y.,LandOcean Energy Services Co. | Zuo S.,Sinopec | Ba J.,Petrochina
Shiyou Diqiu Wuli Kantan/Oil Geophysical Prospecting | Year: 2012

This paper presents a multiple attenuation approach for Australian marine seismic data. In view of long path and peg-leg multiples significantly growing, comparisons of different multiple attenuation methods are made and the strategies of combined multiple suppression are proposed. The steps of multiple attenuation shows as follows: (1)Radon transform is performed after the first round of velocity analysis to attenuate most of the long-path multiples. (2)Predictive deconvolution is used to attenuate most of the peg-leg multiples. (3)High precision Radon transform is performed after the second round of velocity analysis to attenuate residual multiples. (4)Radon transform plus inner mute is performed on CPR gathers to suppress peg-leg multiples with small time differences. The results prove the efficiency of this combined approach. Primary reflections are improved. Source

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