The Research And Application Of Reverse-time Migration In North Area Of Jiang Su

The main complex fault zones in the Subsag of Subei Basin are all in the periphery of oil-generating sub-sag,with good oil source conditions and favorable reservoir-forming conditions.The types of oil and gas reservoirs in these areas are diverse,the accumulation is complex and the remaining resources are large.Although exploration has been carried out for many years,there is still considerable exploration potential,which is still the focus of exploration.According to the actual data processed in the past,some three-dimensional images have not achieved the desired results,mainly reflected in the local complex structural parts,the imaging accuracy of strata and sections is not enough,and the purpose of fine description of structural details can not be achieved.Besides the uniformity of coverage times,the consistency of energy and the reduction of tomographic inversion accuracy by residual multiple waves on point offset gathers,another important factor affecting depth migration imaging is that the accuracy of velocity model is not enough to meet the imaging requirements,which also directly affects the imaging effect of the final reverse-time migration.Therefore,it is necessary to study the velocity modeling and reverse-time migration technology of pre-stack reverse-time migration in depth.Firstly,the exploration status of the North Jiangsu Basin is analyzed in detail,and the geological conditions and data characteristics of the area are introduced.Secondly,considering the characteristics of the actual seismic data in northern Jiangsu Province and aiming at improving the imaging accuracy in complex areas,the basic data processing methods of pre-stack seismic data and pre-stack data processing methods suitable for pre-stack reverse-time migration in this area are studied,so as to make full preparations for reverse-time migration.Then,the theoretical research,velocity modeling technology and key parameter measurement of pre-stack reverse-time migration are carried out.Trial and other applied research has focused on the establishment and optimization of velocity model.Kirchhoff integration method for pre-stack depth migration and tomographic velocity inversion technology can be used to obtain high precision velocity depth model.The accuracy of velocity analysis is effectively improved,and a set of suitable modeling methods is determined,which has achieved good results in practical application.Finally,through the application of pre-stack reverse-time migration technology in actual data,a large number of detailed experimental analysis,results comparison and research work have been carried out,the imaging accuracy of complex fault zone data in North Jiangsu Basin has been improved,abundant research results and knowledge have been obtained,and a set of three-dimensional pre-stack reverse-time migration processing methods suitable for the characteristics of data in North Jiangsu exploration area has been summarized and formed.