College of Geo-Exploration Science and Technology in Jilin University��Changchun 130026

Reverse time migration has become a standard imaging tool of complex structure such as salt model�� strongly steep reflector and nappe structure��for their high precision��adapting to strong velocity variation and being free of reflector angle�� The imaging condition requires the source wavefield and receiver wavefield could be obtained simultaneously��which could result in storage shortage and tremendous I /O time when large-scale data is faced�� The imaging condition could also arouse low frequency artifacts in wave propagation path�� Thus��a RTM scheme is proposed�� To the storage and I /O problem��we use source wavefield reconstruction to ensure that the source wavefield and receiver wavefield can be available simultaneously�� It means that in the forward modeling of source wavefield��we only need to store the wavefield around the imaging region and that of the last two time slices as boundary condition and initial condition of reconstruction�� This strategy could decrease storage and I /O requirements greatly�� We also combine up-down��left-right going wavefield decomposition imaging condition with Laplace filter to remove the artifacts of RTM�� This method works well in testing�� The significance of this scheme is that it could improve the method of removing artifacts in RTM��which could help to deal with the complex geological structure and give a high-quality image��and with the use of source wavefield reconstruction��it can decrease the storage and I /O time of RTM greatly��