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Dongying, China

Dong L.-Q.,China University of Petroleum - East China | Li Z.-C.,China University of Petroleum - East China | Liu L.,Shengli Well Logging Co. | Li Z.-N.,China University of Petroleum - East China | Sang Y.-Y.,China University of Petroleum - East China
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2012

In order to avoid the loss of effective signal or incomplete suppression of random noise because of single threshold selection in the curvelet threshold denoising method, a new curvelet threshold denoising method based on empirical mode decomposition (EMD) was proposed. Firstly, noise signal was decomposed into a series of intrinsic mode functions (IMF) by EMD. Then according to the distributing level of noise in each IMF, different thresholds were chosen to process the IMFs with noise. Finally, denoised signal was obtained by reconstructing the denoised IMFs and the IMFs without noise. Thanks to the introduction of EMD, different threshould can be chosen to apply to IMFs with various degree noise. In this way, the method can overcome the shortcomings of single threshold selection of Curvelet threshold denoising method. Applying this method to synthetical and real field data sets indicate that it can improve the signal-to-noise ratio, meanwhile, also greatly maintain the effective signal. The method is proved to be an effective and preserved-amplitude denoising way. Source


Dong L.-Q.,China University of Petroleum - East China | Li Z.-C.,China University of Petroleum - East China | Wang D.-Y.,China University of Petroleum - East China | Liu L.,Shengli Well Logging Co. | Gao J.-W.,Petrochina
Shiyou Diqiu Wuli Kantan/Oil Geophysical Prospecting | Year: 2011

In view of the loss of effective signal of conventional ground-roll removal techniques, in this paper we develop a new multi-scale and multi-directional method of removing ground roll based on the second generation Curvelet transform. Firstly, the seismic data is assigned to multiple scales and directions by Curvelet transform. According to different characteristics of ground rolls and waves in different scales and different directions, a flow of ground-roll removal based on multi-curvelet transform is devised. Making full use of the characteristic of non-overlapping in Curvelet domain, Curvelet coefficient that only contains ground rolls is processed. Finally we get the ground roll removal data. Applying this method to synthetical data and real field data sets indicates that it can suppress ground rolls, meanwhile, also greatly maintain signals. The method is proved to be an effective and preserved-amplitude denoising approach. Source


Zhao Z.-Y.,Petrochina | Gu J.-Y.,Petrochina | Guo Y.-R.,Petrochina | Alimujiang,Shengli Well Logging Co. | Wu Z.-B.,Zhuangxi Oil Production Plant of Shengli Oilfield
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

By means of analyzing sedimentary microfacies, structure features, diagenesis, porosity and permeability and geochemical testing data, the mechanisms of generating abnormal overpressure and its influences on super-low permeability reservoir of upper Es4 member in Chexi depression were discussed detailedly. The results show that the principal mechanism of generating abnormal overpressure is disequilibrium compaction, and the secondary is mineral diagenesis. The formation temperature increasing and diagenesis deepening with depth are inhibited by abnormal overpressure. In the abnormal overpressure section, secondary porosity is relatively well preserved, which is a favourable condition for oil and gas exploration and development. In argillaceous sandstone-based super-low permeability reservoir, it is not a linear relationship between oil and gas production capacity and formation pressure coefficient, as a higher capacity corresponds to the pressure coefficient of 1.2-1.3. This phenomenon results from single sand body thickness (sand-mud ratio), physical parameters, oil saturation and pressure sensitivity and so on. Source


Xu X.-K.,China University of Petroleum - East China | Chen X.-L.,China University of Petroleum - East China | Fan Y.-R.,China University of Petroleum - East China | Li X.,Petrochina | And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

The influence factors of Stoneley wave were researched based on the theory of porous media acoustics. The effect of different factors on the phase velocity and attenuation of Stoneley wave was analysed systematically. After the sensitivity analysis using forward modeling, a method of borehole fluid calibration was proposed. Through a new derivation of the transfer matrix of Stoneley wave forward simulation under different borehole diameter conditions, the transfer matrix was established as a function of logging interval length. On this basis, combining with the permeability calculation methods through the amplitude and phase of Stoneley wave, the permeability of formation was calculated with the simulated annealing algorithm. It can be seen that the larger permeability, the more reliable the results. The results agree well with the core data, the conventional data and the mudstone profile, and can meet the requirements of field application. Source

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