2. Outline
• Introduction and theory
• Numerical model
• Case studies
– Case 1 – Mediterranean
– Case 2 – integrated study 1
– Case 3 – integrated study 2
7. Why diffraction?
• strong need for small-scale natural fracture and
fault detection
• seismic wavefront contains certain fracture
information, difficult to extract
• diffraction, key to higher resolution
8. MultiFocusing diffraction imaging (MFDI)
• MF imaging stacks large number of traces and
increases S/N ratio
• weak seismic events are enhanced
• diffraction energy contains important information
but is weak and sensitive to noise
• MF diffraction imaging methodology increases
diffraction S/N ratio
9. Diffraction stacking – a special case of
MultiFocusing stacking
Diffraction moveout coincides with MultiFocusing moveout when the
reflection interface shrinks to a point, i.e., when RCRE = RCEE.
10. Outline
• Introduction and theory
• Numerical model
• Case studies
– Case 1 – Mediterranean
– Case 2 – integrated study 1
– Case 3 – integrated study 2
17. Outline
• Introduction and theory
• Numerical model
• Case studies
– Case 1 – Mediterranean
– Case 2 – integrated study 1
– Case 3 – integrated study 2
24. Outline
• Introduction and theory
• Numerical model
• Case studies
– Case 1 – Mediterranean
– Case 2 – integrated study 1
– Case 3 – integrated study 2
25. Integrated diffraction case study 1
Goal – predict fractured zones within unconventional
reservoir onshore Europe
formation: oil-shale
average thickness: 40 m
well data:
– log data of six wells
with old and poor logs
– incomplete well tests
– key information on two
wells kept back as blind
test
26. Integrated diffraction case study 1
formation: oil-shale
average thickness: 40 m
seismic data
– diffraction
– amplitudes
– attributes
27. Project scope
– seismic structural interpretation, seismic
attribute analysis
– MultiFocusing diffraction imaging
– petrophysical analysis and well log
interpretation
– clusters and statistical analysis
– geological review and conclusion
33. PSTM in background, diffraction image in
color
Well A Well B
increasing evidence of
fracturing and facies change in
areas of uplift and compression
34. PSTM in background, diffraction image in
color
increasing evidence of
fracturing and facies change in
areas of uplift and compression
35. of fractures
additional
Petrophysical results and diffraction
meability
Trace of Diffraction
p_ nk image
trace along well paths
US-7
APS Lithology index
Resistivity from tool
VSH with big and short Parametr of fractures
radius of investigation Truth Formation and additional
NGK60 PZ resistivity permeability
Trace of Diffraction
GR BK Flush zone resistivity Kp_nk image
Q 16
н=
3
м/сут
Кровля баж.
свиты
Сухо
Кровля абалак.
свиты
36. Diffraction amplitudes and well results
diffraction image horizon map production rate vs diffraction
amplitude
B
C
A production rate
diffraction amplitude
correlation coefficient = 0.7
37. Diffraction amplitudes and well results
diffraction image horizon map in situ porosity vs diffraction
amplitude
B 80
y = 33.229ln(x) + 26.969
R² = 0.8827
70
y = 22.734ln(x) + 21.653
in situ porosity (%)
60 R² = 0.8434
B
C 50 y = 32.477ln(x) + 30.932
A R² = 0.8434
40
Qsr
30 C
A Q2
20
Q3
m
u
o
n
L
v
a
e
r
l
i
10
0
0 1 2 3 4
Diffraction image, у.е
diffraction amplitude
average correlation coefficient: 0.85
38. Attribute horizon maps around various well
locations composite map: first derivative of
envelope, diffraction amplitude,
temperature, pressure
calculated in situ porosity map
BB B
C C C
A A
A
39. Outline
• Introduction and theory
• Numerical model
• Case studies
– Case 1 – Mediterranean
– Case 2 – integrated study 1
– Case 3 – integrated study 2
40. Integrated diffraction case study 2
Goal – predict fractured zones within unconventional
reservoir, onshore Americas
100041300222W400
formation: oil shale
Resistivity and Properties Porosities Param ether of fractures Paramether of fractures Param ether of fractures
n imp
D of flush zone DEN KPnk_gk KPfrac2 DIFR2DDIV100 KPfrac9 0 10 7000 21000
Dzona2 2300 2900 0 0.2 0 0.001 0 0.014 0 0.001 LIT PE
5 10 DT KPfrac1 KPfrac4 KPfrac11 1 5 0 10
MD,м
RES_DEP 150 300 0 0.001 0 0.001 0 0.001 GR
average thickness: 11 m
0 2000 GR KPfrac6 KPfrac10 0 500
RES_MED 0 500 0 0.0001 0 0.001 DEN
0 2000 den_correct SEISMIC 2300 2900
RES_SLW 2300 2900 -8000 8000
0 2000
2480
well data:
2500
– six wells were within the
2520
2540
survey limits 2560
– only five could be used 2580
– old wells with
2600
2620
incomplete information 2640
D flash zone
41. Integrated diffraction case study 2
Goal – predict fractured zones within unconventional
reservoir, onshore Americas
formation: oil shale
average thickness: 11 m
seismic data
– amplitudes
– attributes
– diffraction amplitudes
– diffraction velocities
42. Project scope
– diffraction imaging
– seismic attribute analysis
– petrophysical analysis and well log
interpretation
– clusters and statistical analysis
– geological review and conclusion
52. Summary
• three case studies
• petrophysical analysis – natural fracturing,
in situ porosity
• MF diffraction amplitude - calibrate to wells
• calculate seismic attributes
• all data types integrated
53. Conclusions
• correlation between diffraction amplitudes and
natural fractures
• prediction of fracture swarms in tight shales
• integrating other data types enhances fracture-
prediction accuracy
Notas del editor
Slide 10 ANIMATE SLIDE R+ and R- in the Multifocusing moveout correction formula are connected to two fundamental wavefronts corresponding to the normal and normal-incidence-point waves. Rcre and Rcee are the curvature radii of those two wavefronts. The CRE wavefront (CURVE ON LEFT PUCTURE STARTS BLINKING) is formed by a point source placed at the reflection point of the normal ray. The CEE wavefront (CURVE ON RIGHT PICTURE STARTS BLINKING) is formed by normal rays emitted from different positions of the reflector, as in the exploding reflector scenario.
Velocities for MFDI migration are determined by focusing the diffraction events during migration. In practice this is done by using several different velocities and then picking the one that focuses best.
Thickness map, shows ideas of paleo - structure
The same well but only Neutron porosity – for your choice what will be better to show
The same well but only Neutron porosity – for your choice what will be better to show