Geological Fracture detection -Geomage

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Predict fracture swarms and small offset faults using conventional seismic data

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  • 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
  • Geological Fracture detection -Geomage

    1. 1. MultiFocusing Diffraction Imaging(MFDI)
    2. 2. Outline• Introduction and theory• Numerical model• Case studies – Case 1 – Mediterranean – Case 2 – integrated study 1 – Case 3 – integrated study 2
    3. 3. Theory
    4. 4. Conventional NMO X – source V 1ρ 1 R – receiver V 2ρ 2 offset offset time Before NMO correction After NMO correction
    5. 5. 2D MultiFocusing – 3 parametersCRE radius & CEE radius and emergence angle
    6. 6. Diffraction - definition obstacle wavefront
    7. 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. 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. 9. Diffraction stacking – a special case ofMultiFocusing stackingDiffraction moveout coincides with MultiFocusing moveout when thereflection interface shrinks to a point, i.e., when RCRE = RCEE.
    10. 10. Outline• Introduction and theory• Numerical model• Case studies – Case 1 – Mediterranean – Case 2 – integrated study 1 – Case 3 – integrated study 2
    11. 11. Numerical diffraction model fractures 20 km
    12. 12. Fracture density increases along model length Size of fracture: 1 x 0.3 meter fracturesdepth (m) distance (m)
    13. 13. 2D-model MultiFocusing stack
    14. 14. 2D-model MultiFocusing post-stackmigration
    15. 15. 2D-model MultiFocusing diffractionstack
    16. 16. 2D-model MultiFocusingdiffraction post-stack migration
    17. 17. Outline• Introduction and theory• Numerical model• Case studies – Case 1 – Mediterranean – Case 2 – integrated study 1 – Case 3 – integrated study 2
    18. 18. Case study 1: geology
    19. 19. Geomage MultiFocusing – structure stack
    20. 20. Geomage MultiFocusing – diffraction stack
    21. 21. MultiFocusing – migrated diffraction stack evaporites diffraction values in color on migrated MF stack
    22. 22. Geomage MultiFocusing – diffraction stack
    23. 23. MultiFocusing diffraction velocities smoothed velocity corrected velocity from MF processing from MF diffractions m/s
    24. 24. Outline• Introduction and theory• Numerical model• Case studies – Case 1 – Mediterranean – Case 2 – integrated study 1 – Case 3 – integrated study 2
    25. 25. Integrated diffraction case study 1Goal – predict fractured zones within unconventionalreservoir onshore Europeformation: oil-shaleaverage thickness: 40 mwell 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. 26. Integrated diffraction case study 1formation: oil-shaleaverage thickness: 40 m seismic data – diffraction – amplitudes – attributes
    27. 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
    28. 28. Seismic PSTM amplitudes Well A Well B Well C
    29. 29. Horizon maps time map depth map ? ? ? ?
    30. 30. Temperature map at reservoir temperature (degrees C) 135 Well B 130 125 130 120 115 Well C 110 100 3 105 100 Well A 139 95 90 85 80 75 70 70
    31. 31. Pressure map at reservoir 460 460 Well B 440 pressure (PSI) 420 400 380 360 Well C 3 340 340 320 Well A 300 280 260 240 220 180 200 180
    32. 32. Well-to-seismic ties reservoir reservoir Max.Corr = 0.82 Max.Corr = 0.79
    33. 33. PSTM in background, diffraction image incolor Well A Well B increasing evidence of fracturing and facies change in areas of uplift and compression
    34. 34. PSTM in background, diffraction image incolor increasing evidence of fracturing and facies change in areas of uplift and compression
    35. 35. of fracturesadditional Petrophysical results and diffractionmeability Trace of Diffractionp_ 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. 36. Diffraction amplitudes and well resultsdiffraction image horizon map production rate vs diffraction amplitude B C A production rate diffraction amplitude correlation coefficient = 0.7
    37. 37. Diffraction amplitudes and well resultsdiffraction 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. 38. Attribute horizon maps around various welllocations composite map: first derivative of envelope, diffraction amplitude, temperature, pressurecalculated in situ porosity map BB B C C C A A A
    39. 39. Outline• Introduction and theory• Numerical model• Case studies – Case 1 – Mediterranean – Case 2 – integrated study 1 – Case 3 – integrated study 2
    40. 40. Integrated diffraction case study 2Goal – predict fractured zones within unconventionalreservoir, onshore Americas 100041300222W400formation: 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 GRaverage 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 2480well 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. 41. Integrated diffraction case study 2Goal – predict fractured zones within unconventionalreservoir, onshore Americasformation: oil shaleaverage thickness: 11 mseismic data – amplitudes – attributes – diffraction amplitudes – diffraction velocities
    42. 42. Project scope – diffraction imaging – seismic attribute analysis – petrophysical analysis and well log interpretation – clusters and statistical analysis – geological review and conclusion
    43. 43. Seismic arbitrary PSTM amplitude section Well A Well B Well C
    44. 44. Time map at main target interval
    45. 45. Seismic-to-well tie Well D
    46. 46. PSTM amplitudes around target horizon main horizon minus 30 main horizon minus 12 ms ms F F C C B B A A
    47. 47. Petrophysical analysis calculated fracturing 100052700124W400 Resistivity and D of flush zone Porosity, Litology and clayness Paramether of fractures Traces of seismic attributes, Impedance, Vrelationship (logs) Dzona2 VSH KPfrac 5 16 0 1 0 1E-5 SEISMIC MD,м RES_DEP KPnk_gk DIFR -9000 9000 0 1950 0 0.1 0 0.01 im p RES_MED 10000 25000 0 1950 dV 0.9 1 dVs_p 0 1 2688 2700 depth (m) 2712 2724 2736 2748 2760 2772 2784
    48. 48. Cross-plot, calculated in situ porosityand diffraction in situ porosity (%) correlation coefficient: 0.9 diffraction amplitude
    49. 49. Diffraction interpretation diffraction amplitudemain horizon -12 ms secondary target
    50. 50. Integrating digital elevation model (DEM) anomaly not caused by surface condition DEM diffraction amplitude
    51. 51. Integrating digital elevation model (DEM) anomaly possibly caused by surface condition. DEM diffraction amplitude
    52. 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. 53. Conclusions• correlation between diffraction amplitudes and natural fractures• prediction of fracture swarms in tight shales• integrating other data types enhances fracture- prediction accuracy

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