Fracture reservoir forecasting method based on seismic frequency division coherence attributes

Abstract

The invention discloses a fracture reservoir forecasting method based on seismic frequency division coherence attributes, belongs to oil-gas geophysical reservoir forecasting, aims to provide a fracture reservoir analysis technique which can accurately identify fractures with different scales and forecast distribution rules. The method includes the steps: (1) extracting frequency division coherence attributes with different frequencies of target horizons, and enhancing the attributes; (2) calculating an average value and a variance of four apexes of each grid according to target horizon frequency division coherence attribute data after grid processing; (3) counting the range of a variance value, taking a middle value of the range, counting average values of all grids corresponding to the value, and setting threshold values of fracture units and fracture-free units according to counting results to rapidly and effectively acquire fracture distribution conditions; (4) giving apex averagevalues of the fracture-free units close to the apexes for four apexes of the grid in higher frequency when the grids serve as the fracture units in the data of the target horizon frequency division coherence attributes with the different frequencies to effectively remove coincided portions in fracture forecasting results in the higher frequency and fracture forecasting results in the lower frequency; (5) forecasting a fracture reservoir in a plane mapping mode by the target horizon frequency division coherence attribute data with the different frequencies processed in the steps. According to the method, the fracture units and the fracture-free units are divided based on target horizon frequency division coherence attribute data, and the fracture distribution conditions of the fracture units in data with different frequencies are compared, the coincided portions are removed, so that the fractures with different scales are accurately identified, and distribution rules are accurately forecasted.

Description

technical field [0001] The invention relates to the problem of fracture reservoir prediction in the field of oil and gas geophysics, and is a fracture reservoir prediction method based on post-stack three-dimensional seismic attribute analysis, which is used to provide a fracture reservoir that accurately identifies fractures of different scales and predicts distribution laws Predictive analytics technology. Background technique [0002] Post-stack 3D seismic attribute analysis is an important method for fracture identification and prediction. Using seismic attributes to detect fractures is mainly based on the discontinuity of seismic waveforms, including coherent body, curvature, and dip angle. Due to the multi-scale nature of fractures, how to accurately characterize different fractures, identify and predict the distribution of fractures of different scales has always been the focus and difficulty of research. Many scholars at home and abroad have proposed some technologi...

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Problems solved by technology

[0003] The present invention aims to provide a fracture reservoir prediction and analysis technology based on seismic frequency-division coheren

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