The deep parts of complex prospecting areas such as piedmont zones and ultra-deep strata are usually accompanied by anhydrite-bearing rocks,leading to great challenges to velocity modeling and affecting the final imaging quality and reliability.It is difficult for the conventional grid tomography method to adapt to the severe lateral velocity changes of special geological bodies.To this end,this study introduced a local tomographic velocity modeling method for deep anhydrite-bearing rocks.By constructing a new tomographic objective function for velocity anomalies,the local remaining residuals below the rocks were converted into the velocity update amount of the special lithologic bodies through tomography in order to further improve the accuracy of the velocity model and effectively improve the quality of imaging below the rocks.The actual data processing results have verified the effectiveness of the local tomography method,which will provide effective technical support for oil and gas prospecting in complex prospecting areas.
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