Study On Multi - Frequency Compression Technology And Application Of Seismic Data At Sea

In the offshore oil seismic exploration,multiples are the most serious noise.Due to the existence of multiples,primaries are covered and S/N ratio of seismic datas is influenced seriously.So that it is difficult to distinguish primaries effectively.Therefore,in order to avoid misunderstandings in the subsequent interpretation,it is necessary to remove the multiples from seismic datas.But multiples problem is a worldwide problems and it has not yet been solved well.So researching multiples identification methods and typical multiples elimination methods has a very important practical significance and industrial value.First,this paper introduces current research of multiples elimination technologies.Then we systematically analyse the generation condition,classification,time-distance curve and remaining difference of mutiples.And we combine with practical illustrations to show the different multiples identification methods.Then we discuss the current widely used methods including predictive deconvolution,parabolic Radon transform and surface related multiple attenuation method from different aspects including the priciple,theoretical basis,application conditions,advantages and disadvantages,and give a great deal of applications to test.Aiming at current phenomenon that seismic datas contain a variety of multiples,proposed the idea of a combined multi-suppression’s regimen for multiple elimination.The paper analyses the background of this idea and combined with my understanding discusses the basis and principles of combination regimen.And then we give the two combinations which suitable for shallow and deep offshore seismic data.Finally,we use the combination to test attenuation effect in the model data and achieve good results in shallow and deep offshore seismic datas.Through theoretical analysis and practical application,we know mainly multiples in the seismic datas and their characteristics,the difficulty of removing each of them.Predictive deconvolution,parabolic Radon transform and surface related multiple attenuation method have own suppression characteristics,conditions and ability to suppress multiples.Because each of methods has different targets,so we need combine various methods to attenuate multiples. We can get the high S/N ratio results on condition that avoid injuring primaries and maximize the advantages of various methods.We give combinations for shallow and deep offshore seismic datas with the types and characteristics of multiples in the actual datas.