Liu Huaishan

Frequency Domain Seismic Blind Deconvolution Based on ICA

Independent components ansalysis (ICA) is combined with shot time Fourier transform(STFT) to improve the traditional frequency domain seismic deconvolution in this paper. Neglecting noise, the seismic record is changed from time domain to frequency domain with STFT in order to transform the common seismic model to the basic ICA model. By applying FastICA algorithm, reflectivity series and the seismic wavelet can be produced in frequency domain and changed back to the time domain subsequently. The model and real seismic data numerical examples all show the algorithm valid. The advantage of this new method is to inverse blindly the wavelet and the reflectivity effectively with no assumption of Guassality and whiten noise to reflectivity, and no assumption of minimum phase to seismic wavelet. The algorithm refered here propose a new way of seismic deconvolution and worth doing more researches.

Application of high density resistivity methods in exploring fracture water

High density resistivity method is used widely and is effective in detecting ground water. Ground water is usually enriched in the crack in granite tectonics area. High density resistivity method gathers a lot of electrode, which is an array way of D.C. electric method, so we can choose different electrode arrays according to different situation in actual application. Taking the effect of two detecting programs for examples, this article introduces how to choose fit detecting method due to different topography condition, different geologic geophysical condition in granite tectonics area.

Research on the Forming Mechanism of Multiple Wave in the South Yellow Sea

The purpose of this paper is to fully understand the forming mechanism of multiple wave of the South Yellow Sea. According to W5-st1 well logging parameters and the processing profiles of the cross-well line,we established a geological model and carried out forward modeling studies.To carry out forward modeling studies by using elastic wave equation and considering the differences by changing conditions of the free surface.With the study results and the actual seismic data,we can fully aware the characteristics and forming mechanism of multiple wave of the sea area.

Analysis of Water Features in Gas Leakage Area

In a certain frequency range, gas is an effective absorber and scatterer of sound, which changes the compressibility of water, and then changes the speed and frequency of sound. Gas continues rising, deforming, and dissolving. The same bubble of natural gas has different radii at different depths. By analyzing these changes, the resonance frequency of gas bubble, and its impacts on sound wave, characteristics of the influences of gas at different depths on the incident sound wave can be obtained. The main sound features of gas are relevant to the gas size, gas content, velocity, attenuation, resonance frequency, the scattering cross-section, and so forth. Sound models with hydrate and free gas in the water and sediment are established. Through the practical application to actual data, the sound characteristics yielded when the gas (or gas hydrate dissociation) escaped the water of seismic data are very clear.

Application of pre-stack F-K time migration method in high-density seismic exploration

With increasing difficulty and complexity of seismic exploration for oil and gas, high-density seismic exploration has been widely used as the main technology to increase oil and gas production. Pre-stack time migration technology in frequency-wavenumber domain use non-recursive pre-stack F-K time to achieve migration imaging by considering conditions of metastable phase in common offset domain. Compared with Kirchhoff pre-stack time migration, it has the characteristics of high imaging precision and the ability to process data in steep structure without producing operator aliasing. Model data and real data processing has verified that processing data by pre-stack F-K time migration method in high-density seismic exploration is correct, effective and practical.

Notice of Retraction Analysis on the Spatial Resolving Power for Seismic Trace

The spatial resolving power for seismic trace before migration is usually estimated by the size or the extent of the first Fresnel zone. Based on the ray path theory, the first Fresnel zone only resolves the kinematics problems of wave propagation. So its unable to demonstrate those dynamics characteristic of wave propagation, especially in the complicated seismic wavefield. To obtain a better understanding of the concept of the spatial resolving power for unmigrated seismic data, we had better investigate the spatial resolving power for seismic trace using the theory of generalized diffraction. In this study, we derive the spatial resolving power formula for zero-offset seismic trace with the total response of generalized diffraction stack. And then we demonstrate how to estimate the spatial resolving power for zero-offset trace with the formula. The numerical modeling results confirm the validity of this formula and show that it can deal with the kinematics and dynamics problems of wave propagation in seismic wavefield.

A Study on Bubble Effect Mechanism and Characteristics of High-Frequency Sparker Source

Sparker source is one of the non-explosive sources applied to marine seismic exploration. It loads electrical energy pre-storaged in the capacitor on the electrode in the water, then produces pulse pressure wave by discharge effect. But at the same time associated bubble effect occurs, which has greatly decreased the signal to noise ratio in marine seismic acquisition. This paper theoretically analyzes the mechanism and characteristics of bubbles effect and their adverse impact in marine seismic exploration.

Marine Linear Noise Suppression in the Curvelet Domain

Marine seismic data are often contaminated by linear noise which has high amplitudes. The recorded noise degrade the quality of marine seismic data. To obtain the desirable data, we should suppress the noise with minimal impact on the desirable data. Considering the characteristics of the curvelet transform, we present a method of removal of the linear noise in the curvelet domain. The proposed method is tested on a synthetic shot record with strong linear noise. Also it’s tested on a real shot record. The denoising results prove that our proposed new method is a promising method of suppression of the linear noise.

Adaptive Control and Synchronization of a New Uncertain Hyperchaotic Lorenz System Based on Parameter Identification

In this paper, the problems of control and synchronization of a new hyperchaotic Lorenz system with uncertain parameters are studied. Based on the Lyapunov stability theory and the adaptive control theory, this new uncertain hyperchaotic Lorenz system is suppressed to its unstable equilibrium. Furthermore, synchronization between two identical uncertain hyperchaotic systems is achieved by proposing an adaptive control law and a parameter estimation update law. Numerical simulations are presented to demonstrate the analytical results

Interpretation of Marine High Resolution Shallow Seismic Profile

This paper studies the interpretation of high-resolution shallow seismic profile. Firstly, it is necessary to do some indoor fine processing to get a high quality profile, such as adaptive filtering, true amplitude recovery, tides differences and so on, especially the processes to remove the multiple waves. Based on the theory of seismic stratigraphic and combined with the previous survey data and drilling information, eight major targets are interpretated to describe quaternary sediment of this study area. Meanwhile, this paper analyzes the feature and the possible stratigraphic time of each layer. In addition, the database for interpreting is created by using the human-computer interaction way in a workstation, which makes the recognition of the characteristics of sedimentary layers much easy.