The Study Of High Density Seismic Data Processing

With the development of the petroleum exploration now, the accuracy grade of seismic section is needed higher than before. The seismic data with big cell size, low fold and narrow azimuth does not meet the demand of the high-precision petroleum exploration, so the technology of processing of seismic data with the high-density and wide azimuth is received more and more attention. How to make good use of the characteristic of high-density seismic data to improve the S/N effectively and to achieve fidelity in noise suppressing with current technology? In order to function in different frequency band, how to compensate the high & low frequency of signal reasonably when we process the seismic data? How to fully take advantage of the information of high-density seismic data and play the wide azimuth data’s role to get high quality azimuth data? Based on the conventional seismic data processing, a series of issues need to be more explored and tested.The research in this paper was based on the project of China’s Oil and gas exploration and Development Company’s "High-Density 3D Seismic Data Processing on A survey". According to the geological tasks of the high-density 3D seismic data, it is key point to improve the fidelity of date, improve image the events and faults by make full use of the characteristics of itself. After a lot of experimental analysis and research, the study of the targeted technology application and methods were achieved as following: First, according to the characteristics of the noise in the high-density seismic data, analysis the similarities and differences between conventional seismic data and high-density, apply the targeted high density data fidelity de-noise processing technology which cover Anomalous Amplitude Noise Attenuation, cross-spread cone filtering de-noise and so on, attenuate the noise step by step in different domain and improve the signal-to-noise ratio of seismic data. Second, broadband compensation process: first, the application of well constraint Q compensation will compensate the phase of seismic wavelet and amplitude in different frequencies band at two aspects of energy and phase. Then, in the low frequency source wavelet amplitude characteristic in low frequency band as constraint, the Low Frequency Boosting with source wavelet was used to compensate the attenuated low frequency and recover the contribution of low frequency information to deep part imaging. Finally, by the technology of well constraint de-convolution, the wells in the survey are used to the de-convolution’s constraint. According to the match of the synthetic records and migration section with different de-convolution parameters, cross-correlation peak and similarity value of quantitative analysis method for optimizing parameters of de-convolution and quantitative monitoring. Not only improving the resolution of seismic data, but ensure the seismic data with high fidelity. Third, the processing of wide-azimuth seismic data. According to the characteristics of the seismic data, in order to take advantages of wide azimuth seismic data, the process techniques in offset vector title(OVT) domain was applied during the seismic data processing and the high quality seismic data can be obtained. After offset vector title(OVT) processing, the azimuth in seismic data for subsequent processing is complete kept. It’s better for the azimuth anisotropy analysis and fracture detection in geological interpretation.The research of this paper is based on the real seismic data, and a set of seismic data processing was found for high-density wide-azimuth seismic data. In order to further prove that this study of the technology method is reliable and reasonable, the processing results between conventional seismic data and high-density are compared. The processing results also provided the higher accuracy data for the buried hill fracture prediction and the implementation of the petroleum.