Study On The Prediction Of A Reservoir Crack In J₂s₁ Section Based On Curvature Properties

In the development of sandstone oil and gas reservoirs with low porosity and low permeability,fractures are a key factor affecting the high and stable production of tight sandstone reservoirs.In order to achieve the goal of high and stable production of tight sandstone reservoirs,research on the prediction of fracture development and distribution has become the focus and difficulty of low-porosity and low-permeability sandstone reservoir research.The distribution of cracks is subtle and complex.Based on post-stack seismic data,the use of curvature attribute analysis technology can accurately reflect and predict the crack development law.The most important feature of the Shaximiao Formation bottom boundary of the GSM block in the central Sichuan area is the relatively developed faults and fractures,and these features are crucial to the storage and migration of oil and gas in the Shaximiao reservoir The role.According to previous research data,the deep strata of the GSM block still have great resource potential and exploration prospects.Therefore,this paper uses the 3D seismic data stitched from the seismic data obtained from the seismic exploration of the GSM block in the central Sichuan area in 2000 and subsequent years to extract the curvature attributes and carry out the cracks and faults in the first member of the Shahe Formation in the GSM block in the central Sichuan area.prediction.The main results include:(1)Aiming at the problem of how to extract curvature attributes from seismic attributes,two methods for extracting curvature attributes from post-stack seismic data are proposed.One is to use Roberts' 3 × 3 gridded 9-point difference method to calculate A variety of curvature attributes at any point on the trend surface fitted by a section of the stratum to achieve the purpose of extracting the curvature attributes of the first section of the Sha;the second is to calculate the volume curvature attributes of the three-dimensional seismic data volume and use the discrete derivative algorithm to dip the seismic data volume The data obtains the first derivative to obtain various volume curvature properties.Through these two methods,the surface curvature attribute and volume curvature attribute data volume of the first member of Shahejie Formation were obtained.The original seismic data volume profile was compared with the extracted curvature attribute data volume profile and the fracture system profile combined with conventional seismic data interpretation.The fractures and fractures of the Sha 1st Member of the GSM block in the central area are best extracted and can be applied to the curvature properties of fractures and fractures prediction.(2)For the problem that the curvature attribute is sensitive to the noise in the seismic data volume and the noise affects the accuracy of extracting the curvature attribute and the subsequent use of the curvature attribute to predict the accuracy of cracks,two seismic data preprocessing methods(Gaussian filtering and structureoriented Filtering)suppresses the noise in the seismic data and obtains a better curvature attribute crack identification effect.At the same time,the main influencing factors of the filtering effect are discussed,such as the size of the filtering window and the number of iterations,and in the case of the filtering window size and the number of iterations using the best filtering effect,the two post-stack filtering methods of Gaussian filtering and construction-oriented filtering are compared.For the noise suppression effect of seismic data,the best filtering method is selected.(3)Aiming at the problem that the single method of curvature attribute is used to predict the reliability of fractures in the first member of the Shahejie Formation,the post-stack coherence attribute and seismic data structure are used to finely interpret the method and volume curvature combined with the plane and volume curvature attributes Attributes combined with the method of ant tracing technology have resulted in more accurate fracture prediction in the Sha 1 formation of the GSM block.First,the structure is used to explain the large-scale faults in detail,and the distribution of faults that control the structural fractures is given in combination with the post-stack coherence properties.On this basis,the surface curvature curvature distribution map calculated according to the first member of the Shahejie Formation is calibrated,so as to predict the distribution of fractures in the first member of the Shahejie Formation of the GSM block in the central Sichuan area.In the same way,we calibrate the distribution map of volume curvature attribute according to the first member of Shahe Formation to predict the development area of fractures.Combining the ant tracking technology with the curvature attribute,the ant volume module of Geoeast software is used to establish a crack model to obtain the plane distribution of the crack and other geometric information.