Research And Application Of Azimuth Strengthening Curvature Analysis Technology

With the deepening of oil and gas exploration,exploration targets have gradually turned to concealed hydrocarbon reservoirs and complex structural reservoirs,which requires us to extract more detailed information from existing seismic and geological data.It is well known that geological phenomena such as faults,fracture systems and folds are closely related to tectonic movement.However,due to the different directions of tectonic movements at different stages,these geological phenomena tend to be distributed in multiple directions.As a representative discontinuity property,curvature attribute are widely used in the identification of faults,cracks and other typical geological structures,but the conventional curvature attribute cover all-round information,which is not conducive to our analysis of specific azimuth.Therefore,this paper develops a series of azimuth strengthen curvature analysis techniques,including:(1)Research of azimuth curvature attribute and application of actual seismic data.Firstly,this paper introduces the calculation method of two-dimensional curvature attributes,deduces the7×7grid calculation,and discusses the limitations of two-dimensional curvature attributes in actual production.And with the help of instantaneous parameters,the three-dimensional curvature attribute analysis method is deduced.Compared with the two-dimensional curvature attribute,this method has better noise resistance,more in line with the actual production needs,and can more comprehensively express the underground geological structure information.Because the traditional seismic curvature attribute analysis cannot effectively use the azimuth information in seismic data,considering the direction of fault and fracture development,this paper improves the azimuth curvature algorithm to strengthen the azimuth information in seismic data,so as to exclude the interference of other undesired directional information and obtain more accurate structural information such as faults and fracture zones.(2)Anisotropic diffusion filtering method.This paper mainly introduces two filtering methods of curvelet transform and multi-layer complex field nonlinear anisotropic diffusion filtering.Because curvature analysis requires data with high signal-to-noise ratio,filtering processing is extremely important.Curvelet transform is an improvement based on Fourier transform and wavelet transform.It is characterized by high anisotropy,good ability to express information at the edge of image.Because of its unique multi-scale and multi-direction characteristics,Curvature transform has its unique advantages in restoring the main structure of image edges and suppressing peripheral noise.For multi-layer complex field nonlinear anisotropic diffusion filtering,in order to overcome the shortcomings such as the inability to filter out edge noise during processing,the Shock filter was added to the anisotropic diffusion term in complex domain,and the linear field anisotropic diffusion filter was developed from the linear field to the nonlinear field.The complex-domain nonlinear anisotropic diffusion filter can maintain the seismic data in-phase axis edge information while suppressing noise,enhance the lateral continuity of the seismic in-phase axis.It can provide a basis for the calculation of azimuth curvature attribute.