GLOBE Claritas™

Radon Demulitple using PRT_DEMULT

www.globeclaritas.com

Modelled Gather and Parameters120 Traces

Offsets 100 to 3075 metres

25m increment

Seafloor at 400ms TWT

Click on ruler with RMB

This selects Parabolic Ruler

Can measure “far offset moveout”

Primaries are flat

Multiples down dip

1200ms far-offset moveout

~40ms far-offset moveout

348ms far-offset moveout

328ms far-offset moveout300ms far-offset moveout

677ms far-offset moveout

Need to model data to include full positive range of “far offset moveout” values

www.globeclaritas.com

Modelled Gather in Radon Transform SpacePrimaries are flat : P=0

Multiples down dip: P= =ve

1200ms far-offset moveout

~40ms far-offset moveout

348ms far-offset moveout

328ms far-offset moveout300ms far-offset moveout

677ms far-offset moveout

P=0

Note that events form crosses in Radon Transform Space

PRTF performs the Radon transform

350 p-values used in this case

Moveout range from -400 to +1600ms

2000ms total for the transform

Each p-value corresponds to 2000/350 = 5.7ms

Nyquist for 5.7ms sample interval is 87.5Hz

P value is in COR trace header, plotted over data in this display

Gather Shallow events (~500ms) with few

traces not well resolved

Module : PRTF

www.globeclaritas.com

PRT Demultiple Applied to these dataPrimaries are flat : P=0

Multiples down dip: P= =ve

P=0

Moveout range from -400ms to +1600ms

Removing +30ms to +1596ms

Start Time is 630ms

Input

Module : PRT_DEMULT

Output

Not applied above 630ms TWT

Some linear artefacts –“tails” of crosses extend over P=0

Moveout close to Noise_MS cut-limit and so is not fully removed