Automatic Reflection Tomography
B. Feng and H. Wang
Event name: 80th EAGE Conference and Exhibition 2018
Session: Velocity Model Building - Tomography
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 1.31Mb )
Price: € 20
In exploration seismology, the macro-velocity model is often estimated using the kinematic information of seismic data or migrated gathers, such as the stereotomography and tomographic migration velocity analysis methods. In this paper, we propose a new method to estimate the macro-velocity model using the kinematic information of locally coherent events in the prestack seismic data. First, we calculate the slopes and traveltimes of locally coherent events using a sparse decomposition method. Then, we downward propagate two rays from both source and receiver locations using the observed slopes in the initial model. If at a certain depth the sum of two one-way traveltimes is equal to the observed traveltime, the subsurface offset can be measured. The velocity model can be updated by minimizing the square of subsurface offset iteratively. Numerical example demonstrates that the proposed method has a low dependence to the accuracy of initial model. Meanwhile, it neither requires low-frequency seismic data and/or long-offset acquisition. The high computational efficiency and automatic inversion strategy make it quite promising for macro-velocity model building.