Statics

Please explain the static application in Claritas verion 5.5. how data moves to floting dtum and how data moves from floting to final.

Attached is the Claritas documentation describing the static application and datum corrections.
Let us know if you have any further questions after reading this.

what is the best way to back from final-datum to floting-datung?

you could try using the STATIC module to apply the <lineid>_fltcdp.shf file, applied in the DATUM_SRD module to get the final datum, but set the UPDOWN parameter in STATIC to DOWN - to swap the signs of the time shifts.

please share the job deck to apply the static in claritas, how we shift th edata to floating datum and then floting to final. the jobdeck is useful help for us plase share it.

Attached are simple job flows for applying the floating datum (DATUM_FLT) and the final seismic reference datum (DATUM_SRD). These job flows use data from the land tutorial.
Both modules (DATUM_FLT and DATUM_SRD) require a file defining the floating datum, this is created in the Geometry application as detailed in section 3.5 of the land tutorial handbook.
You would normally correct to the floating datum prior to velocity analysis, residual stacks and pre/post stack migration, only reverting to the final reference datum for output or display. Thus the different input into the DISCREAD modules of the two job flows. Furthermore DATUM_SRD should only be used when DATUM_FLT was previously used to correct the seismic data from the acquisition datum to the floating datum (as in the floating_datum.job)

Do we need to use refraction statics when processing seismic reflection data ??

Refraction statics corrects for variation in near surface terrain. On land seismic surveys, we can expect the near surface terrain to vary significantly. In a few meters we might go from soft, marshy ground to a weathered outcrop. This can lead to large, localised velocity variations which distort the seismic travel times. Static shifts to correct for this can be obtained by using a 'replacement velocity'. One approach to estimating this velocity is to model it from the first-arrival picks of a seismic reflection survey; this will give an estimate of the low velocity layer and its thickness. A static shift model can then be developed to correct for this layer.