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Surface Wave Characteristics And Its Application In Seismic Wave Field

Posted on:2007-07-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:J LiFull Text:PDF
GTID:1110360185469916Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
In the petroleum prospecting, the near-surface investigation adopt generally weathering refraction, small log, first arrival time of normal seismic records, but these methods all adopt of refractive technology. Know to all, The refract wave exist an precondition, that is the bottom medium velocity is bigger than upper, then medium interface produce the refractive wave, if the medium exist the speed turn in reverse, and low speed in false bottom, the medium interface can not calculate. At present, one of the difficult of the petroleum prospecting is the static correction about low frequency in the complex low-signal-noise ratio area, about the low velocity layer in huge thick area, calculating construction of the near-surface inverse by Rayleigh wave ,we provides a complete set of way of thinking.. This paper just searches how use character of Rayleigh wave ,and apply it the near-surface investigated of petroleum prospecting.Ground roll (Rayleigh wave) is a sort of the sub-wave that travels along the interface of medium. It's energy rapidly decline along with the bigger distance to the interface. Rayleigh wave include geology information about earth as reflect and refract. The article adequately illuminate that the near-surface investigation by the analysis of the surface wave technique, including Rayleigh wave of a gun record in petroleum prospecting and transient state Rayleigh wave prospecting , is viable through conception, wave equation, frequency disperse equation, frequency disperse character, three layer medium mode analysis, high grade seismic positive model, seismic inverse model (include normal strata and special strata) and practical application etc.I make sure two scheme that by extracting Rayleigh wave, calculating frequency disperse curve, interpreting frequency disperse curve, inversing by improve damped minimum two multiplication, at seismic record in difference region and difference case. The first scheme is that utilize Rayleigh wave of a gun record of petroleum prospecting to illuminate the near-surface investigation ,second scheme is that make use of transient state Rayleigh wave prospecting to illuminate the near-surface investigation. Through validation of practical application, the two scheme is viable and valid.
Keywords/Search Tags:frequency disperse curve, Rayleigh wave, wave equation, damped minimum two multiplication, transient state Rayleigh wave prospecting
PDF Full Text Request
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