Study On Fine Structure Interpretation Method Using OVT Domain Seismic Data Of Coalfield

Compared with oil fields,faults,collapse columns,and bending structures that are commonly developed in coal fields are generally small in scale.However,these small structures are essential for coal mine safety.In particular,gas is enriched near faults,synclines,and bending structures.there is a danger of coal and gas outbursts.Once these areas are disturbed by mining.In addition,conducted faults and collapse columns are prone to cause water inrush disaster,and seriously affect the layout and driving of roadways,thereby increasing the difficulty of coal mining.Therefore,it is of great practical significance to find out the distribution of small and micro-structures in the mining area for the safe and efficient mining of coal mines.3D seismic exploration technology is an effective means of identifying structures in the mining area.However,due to the limitations of conventional coal field seismic data processing and interpretation techniques,the resolution and retention of seismic data are low,resulting in the current 3D seismic technology’s ability to identify small faults and small collapse columns is not high,and it is difficult to meet the need of mine exploration.Compared with conventional 3D seismic data,OVT domain seismic data contains azimuth and offset information.The 5D seismic data interpretation technology,which is suitable for this data,is a hot technology in recent years and has already been applied to oil seismic exploration.How to use this technology to improve the recognition accuracy of small and micro-structures in coal fields is an urgent problem facing coal mine seismic exploration.This time,establishe a process of structure interpretation based on the OVT domain,and forme a method of seismic data interpretation in the OVT domain of coal fields,and applie to the interpretation of actual data.Firstly,classify structures with different properties and scales in the mining area,study the planar distribution characteristics on the basis of classification,and group the main structural orientations in the study area based on the research results;on this basis,the geological orientations are converted into seismic processing orientations to determine the corresponding sub-azimuth angle.Secondly,comparatively analyze the abnormal response of seismic section perpendicular,parallel and oblique cross sections to the structural orientation azimuth,then combine the structural groupings to form the dominant azimuth;again,based on the all-azimuth data,to choose the optimal attributes,baseding on the structural recognition rate.Then,calculate the attribute of the dominant azimuth data,and fusion the attribute of the dominant azimuth by using PCA and interpreta the structure.Comparing the interpretation results with the actual exposed structure,the results show that the verification rate of the dominant azimuth interpretation method based on the OVT domain can reach 75%,which is about 5% higher than the conventional method.Among them,the accuracy rate of faults above 3m is 75%,the accuracy rate of the collapse column with a long axis diameter of 30m or more is 100%,the recognition rate of the collapse column with a long axis diameter of 20-30m is 40%,and the recognition rate of deflection is 50%.The structural interpretation method based on dominant orientation and preferred attributes is suitable for coal field seismic exploration and has good application and popularization value.