7/31/2019 57 John Castagna 090306

1/45

Spectral Decomposition, SpectralBroadening and High-Resolution

Inversion

John P. Castagna

Oleg PortniaguineMike BurnettShengjie Sun

Fusion Petroleum Technologies Inc.

7/31/2019 57 John Castagna 090306

2/45

Spectral Movie

7/31/2019 57 John Castagna 090306

3/45

Gas Discovery

7/31/2019 57 John Castagna 090306

4/45

7/31/2019 57 John Castagna 090306

5/45

7/31/2019 57 John Castagna 090306

6/45

ExSpect

7/31/2019 57 John Castagna 090306

7/45

DFT 50 msec

DFT 100 msec

CWT Morlet

ExSpect

7/31/2019 57 John Castagna 090306

8/45

ExSpectSynthetic

7/31/2019 57 John Castagna 090306

9/45

Bright Spot Validation

7/31/2019 57 John Castagna 090306

10/45

Bright Spot Validation

7/31/2019 57 John Castagna 090306

11/45

ExSpect

7/31/2019 57 John Castagna 090306

12/45

ExSpect

Downdip/Updip Spectral Ratios

7/31/2019 57 John Castagna 090306

13/45

Interference NotchCWT (and DFT) see composite response

ExSpect

7/31/2019 57 John Castagna 090306

14/45

Progressive loss of high frequenciesonly apparent with ExSpect

Attenua

tion?ExSpect

7/31/2019 57 John Castagna 090306

15/45

Fahmy et al., 2005

7/31/2019 57 John Castagna 090306

16/45

Fahmy et al., 2005

After ExSpect

7/31/2019 57 John Castagna 090306

17/45

Well 1 Well 2

reservoir

reservoir

25 Hz

35 Hz

Macuspana Basin: Bitzal Field

Mendez et al, 2004)

7/31/2019 57 John Castagna 090306

18/45

10hz 60hz

Thicker

Reservoir

Thinner

Reservoir

30hz

Dis-

continuitieshighlighted

7/31/2019 57 John Castagna 090306

19/45

(Tirado, 2004)

7/31/2019 57 John Castagna 090306

20/45

Lessons from Widess

For thin beds- seismic character, peak/trough time,

and frequency dont change with thickness

- amplitude varies almost linearly with

thickness and goes to zero at zero thickness

7/31/2019 57 John Castagna 090306

21/45

Lessons from Widess

For thin beds- seismic character, peak/trough time,

and frequency dont change with thickness

- amplitude varies almost linearly with

thickness and goes to zero at zero thickness

7/31/2019 57 John Castagna 090306

22/45

Reality

The Widess model is not applicable to realreflections

Theoretical amplitude tuning curves are

usually wrong Theoretical limits of resolution are far better

than the Widess model suggests

This knowledge can be used to drive high-resolution inversion of seismic data

7/31/2019 57 John Castagna 090306

23/45

Even and Odd Reflectivity

= +

Mixed Odd Even

7/31/2019 57 John Castagna 090306

24/45

7/31/2019 57 John Castagna 090306

25/45

Odd Total Even

PeakF

requency

Time Thickness

Peak Frequency Versus Time Thickness

wavelength

7/31/2019 57 John Castagna 090306

26/45

Implications

Seismic amplitude and frequency varycontinuously with thickness far below seismicresolution

Thicknesses can be inferred far below the seismicsample rate

Frequencies beyond the bandwidth of the seismicdata can be recovered

This is the basis for ThinMAN broadbandseismic reflectivity inversion

7/31/2019 57 John Castagna 090306

27/45

7/31/2019 57 John Castagna 090306

28/45

7/31/2019 57 John Castagna 090306

29/45

7/31/2019 57 John Castagna 090306

30/45

Porous Limestone

Tight Limestone

Shaley Limestone

7/31/2019 57 John Castagna 090306

31/45

Red = Well Reflecitivty

Red = Well Reflectivity

Blue = ThinMAN

Excellent comparisons to well reflectivity observed

Can always trade-off accuracy versus resolution

Greatest limiting factor is S/N

Comparison to WellReflectivity

7/31/2019 57 John Castagna 090306

32/45

ThinMAN SectionOriginal 3D Seismic Section

Before and After Comparison

7/31/2019 57 John Castagna 090306

33/45

ThinMAN SectionOriginal 3D Seismic Section

Before and After Comparison

7/31/2019 57 John Castagna 090306

34/45

ThinMAN SectionOriginal 3D Seismic Section

Before and After Comparison

7/31/2019 57 John Castagna 090306

35/45

ThinMAN SectionOriginal 3D Seismic Section

Before and After Comparison

7/31/2019 57 John Castagna 090306

36/45

ThinMAN SectionOriginal 3D Seismic Section

Before and After Comparison

Thi MAN S ti

7/31/2019 57 John Castagna 090306

37/45

ThinMAN Section

Original 3D Seismic Section

ThinMANBroadband Sparse

Reflectivity Inversion

No well controlNo a priorimodelNo lateral mixing

No picked horizons usedNo assumed reflectivityspectrum

Boosts high frequenciesrobustly without boostingnoise.

Adds high frequencies

beyond the bandwidth ofthe data.

7/31/2019 57 John Castagna 090306

38/45

7/31/2019 57 John Castagna 090306

39/45

7/31/2019 57 John Castagna 090306

40/45

7/31/2019 57 John Castagna 090306

41/45

7/31/2019 57 John Castagna 090306

42/45

7/31/2019 57 John Castagna 090306

43/45

Cl f fl d i

7/31/2019 57 John Castagna 090306

44/45

Close up of a flattened section

Note the small high and channel not seen in input data

Input Data -90 ThinMAN Data -90

Thi MAN A li i

7/31/2019 57 John Castagna 090306

45/45

ThinMAN Applications

Precise mapping of tops and bases of thin

layers Layer thickness determination

Crisper imaging Stratigraphic Visualization

DHI analysis of thin reservoirs