The Research And Application Of Pre-stack Depth Migration Under The Salt Tectonic

The salt dome structure in the Kazakhstan basin is rich and has a large number of salt and oil reservoirs.Due to the large variation of the velocity between the sedimentary rock and the salt dome,and the development of the surrounding salt,the deep salt migration is a difficult problem in the oil and gas exploration.Subsalt structure pre-stack depth migration includes two main problems of pre-stack depth migration and velocity modeling,according to regional characteristics,this paper studies several commonly used pre-stack depth migration and velocity modeling method,comparative analysis of the characteristics and applicable conditions of each method,and then combined with a block of Kazakhstan characteristics of the study area,combined with the geology a priori information,using the method of geological formation velocity modeling to control the overall structure,in the base geological formation velocity modeling adding formation azimuth,inclination and stratigraphic continuity attributes as constraints,through geological formation velocity control of low frequency structure,grid tomography velocity optimization of high-frequency details,established a velocity model with high precision,the speed provides a reliable model for the final Kirchhoff pre-stack depth migration,so as to effectively solve the study area under salt complex hybrid image problem.This study shows that under salt pre-stack depth migration is a systematic project,the seismic data processing and data quality will affect the final depth migration imaging,the velocity model is the key factor of complex structure pre-stack depth migration under the salt,especially for the study area is very deep,the structure and lithology are complex,Only processing workers and interpreters cooperate,through the integration of processing and interpretation,the high quality and complex velocity model of the salt deposit can be completed.