Optimization And Application Of Velocity Model Building And Depth Migration Method

At present, because of most of the conventional oil and gas resources areas have been prospected, the oil and gas exploration tasks have to face the problems that the surface conditions and underground geological tectonic features are more complex.This is a challenge for accurate imaging of geological tectonic under complex condition.Prestack depth migration is beyond doubt the good choice of completing the challenge,but prestack migration is very sensitive to the accuracy of velocity model.So,how to efficiently build accurate velocity model is a problem we have to solve.The industry application of a new method of building velocity model requires a certain period of time,however,there are so many methods of building velocity model,different methods have their own characteristics and laws. If we could summary them, master them, and use them well.Then we will build velocity model more efficiently.The paper is based on prestack gathers with different complexity,it tests the popular methods at different stages,such as at the stage of building initial velocity model vs depth domain,the stage of the modification of velocity model vs depth domain,and the stage of prestack depth migration,and so on,to summary the laws and characteristics of different methods at different stages.And then,it proposesappropriate methods and practical work flow of building initial velocity model vs depth domain,the modification of velocity model and migration in all kinds of complicated geological conditions, then uses the work flow to process the modeling seismic data,including velocity model building and prestack depth migration. Compared with other conventional methods,the results prove the work flow very effective.The work flow obtains ideal effect of depth domain imaging after applied to the actual data processing.