Research On Seismic Methods For Detecting Fractured Reservoirs

It is important of the study on fractured tight oil and gas carbonate reservoir to geologist and oil reservoir engineers. This paper applies signals processing theory to geophysics, make research in the distribution of fractured oil and gas carbonate reservoir and achieve some knowledge and practical application.By two ways, this paper debates the theory of fracture detection: on one hand by the way of edge detection in image processing; on the other hand by time series analysis. The detection by time series analysis is more antinoise than edge detection in image processing.Edge detection theory in image processing mainly includes correlation data, fuzzy edge detection, entropy operator edge detection and gradient edge detection. Fuzzy edge detection is affected by the choice of crossover point which two sides pixels of are contrasted. The edge by entropy operator is smooth and connected. The algorithms of gradient edge detection by many operator cores are simple. The correlation data can response to general distribution of fracture zones.Based on the characteristic of fractured signal, time series analysis can detect the distribution of fractures. Because of excellent antinoise ability, in high-order statistics theory, the theory of time series analysis includes more information and resolves more problems than second-order statistics.The method of bispectrum can extract characteristic of seismic series bispectrum and detect fracture zones by decreasing dimensions. The method of bispectrum reconstruction detects fracture zones by learning the difference of frequency components because fracture can change the frequency components of seismic responses. The theory of time-frequency analysis computes the difference in the gradient direction of time-frequency spectrum. With the window function, this method has stronger antinoise ability and detects fracture zones more clearly.The research in this paper provides new methods for the detection of fractured reservoir detection, oil field exploration and exploitation and abundant experience of research on fractured reservoir.