Study On Velocity-independent Moveout Correction Using Plane-wave Destruction Filtering

One of the key ways of modern seismic data processing is moveout correction,moveout correction includes normal moveout correction and dip moveout correction.Multiple interference can be effectively suppressed by horizontal stacking, is mainlydepends on the accuracy of NMO correction, and normal moveout correction is animportant means for velocity analysis. The conventional NMO correction is localevents will be flatten, but when the hyperbola is assumed to apply only to theconditions offset equal to or lower than the depth of the reflecting interface. Dipmoveout correction is mainly applied to after the processing of the NMO prestackdata, maintain different stack velocity formations with different dip well. DMOcorrected profile than NMO after correction of CMP gathers section is closer to thezero offset section, better foundation for the subsequent migration processing.Normal moveout correction is established for processing at a known velocityparameter on the premise, by way of velocity analysis, can obtain the requiredparameters. Has now developed a semi-automatic process simplified pick up velocity,but the velocity analysis is still a big workload, time-consuming task. In addition, therelevant parameters of the pickup velocity is often inaccurate, so after NMO treatmentis ineffective, and lead to the increase of complexity and working time. Theprocessing of velocity analysis, to avoid picking up velocity parameters caused by thecomplicated and time-consuming, the correction effect pickup parameter is notaccurate due to poor and the NMO correction stretching distortion exists, thecorrection method on velocity independent moveout correction using plane-wavedestruction filtering. Firstly, the plane-wave destruct the data, access to local eventsand then through the analytic relationship among slopes, the slope and the velocity ofthe shaft together, be found using the local slope can be obtained directly by NMO correction of the desired velocity and all other time-parameters, seismic event canreplace the relevant local slope the velocity parameters of NMO correction.Dip moveout correction for CMP gathers the incline reflection under thecondition of the road is not contained in a common reflection point and the correctionof a seismic processing method, DMO can effectively correct the reflection pointgenerated inclined reflection superposition of the fuzzy phenomenon. Dip moveoutcorrection generally applied to after NMO correction of prestack data, so that theformation of different dips keep stacking velocity different in superposition process.DMO corrected profile compared with the routine CMP gather after NMO sectioncloser to zero offset section, zero offset to facilitate subsequent distance migrationprocessing. The DMO method is independent of the velocity, corresponding to themore close to the actual situation of the correction. The NMO is only applicable to thelevel reflecting layer, independent of the velocity dip moveout correction can makethe large dip good homing. And velocity independent DMO method does not requirethe use of stack velocity parameters, eliminating the influence of dip, through nonzero offset migration to zero offset can be obtained after treatment,3-D migrationdata, further to prestack time migration, and the traditional DMO correction methodcan prove the comparison, treatment effect is independent of the velocity method isalso good.The last is moveout correction on velocity independent using plane wavedestruction filters is calculated by simulation experiments and real data, it is provedthat this method can achieve the same treatment effect of traditional NMO and DMOcorrection method even better and more efficient, it proves that this method iseffective in practice and theory.