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Upscaling Petrophysical Properties to the Seismic Scale. Greg A. Partyka, Jack B. Thomas, and Kevin P. Turco, bp Dan J. Hartmann, DJH Energy Consulting. 8hz Spectral Amplitude Map. Zone 1. WELL #1. 1 mile. Seismic Reservoir Imaging. Seismic Reservoir Imaging. Stratigraphy.
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Upscaling Petrophysical Properties to the Seismic Scale Greg A. Partyka, Jack B. Thomas, and Kevin P. Turco, bp Dan J. Hartmann, DJH Energy Consulting
8hz Spectral Amplitude Map Zone 1 WELL #1 1 mile Seismic Reservoir Imaging
Seismic Reservoir Imaging Stratigraphy • Sensitivity Issues: • Do acoustic properties respond to variability in petrophysical properties? • Scale Issues: • How much seismic resolution is required? ? SEISMIC Petrophysics Structure
Uncertainty and Errors are embedded at all measurement scales. Measurement Scale Uncertainty/Error Examples microns-to-centimetres sampling bias; damaged plugs CORE SCALE centimetres-to-metres washouts; tool problems WELL-LOG SCALE SEISMIC SCALE metres-to-decimetres acquisition & processing artifacts
Upscaling • Three Steps: • Scoping at the well-log scale. • Determining upscaling sensitivity. • Predicting petrophysical properties from seismic impedance.
Are acoustic measurements sensitive to petrophysical properties at the well-log scale? NO YES Seismic will provide little value Hope for seismic detection/resolution Game Over Game Continues to Next Step Scoping at the Well-Log Scale • Cross-plot well-log-scale acoustic properties versus petrophysical properties.
8hz Spectral Amplitude Map Zone 1 WELL #1 1 mile Seismic Reservoir Imaging
Backus Averaged Acoustic Properties Vp=7445 ft/s Vs=3115 ft/s Den=2.23 gm/cc overlying shale Vp=6755 ft/s Vs=3485 ft/s Den=2.17 gm/cc Zone 1 reservoir Vp=7945 ft/s Vs=3260 ft/s Den=2.26 gm/cc underlying shale Scoping at the Well-Log Scale
Acoustic Impedance Water Saturation Effective Porosity Scoping at the Well-Log Scale • Zone 1 Thickness = 57 feet • Backus Filter = None
Upscaling • Three Steps: • Scoping at the well-log scale. • Determining upscaling sensitivity. • Predicting petrophysical properties from seismic impedance.
Upscaling Sensitivity THICKNESS FLOW-UNIT STACKING RESOLUTION VELOCITY BANDWIDTH
Upscaling Sensitivity Analysis • As we scale-up the acoustic data (e.g. bandlimit or decrease thickness): • acoustic resolution of petrophysical properties degrades.
Zone 1 Thickness = 057 ft Backus Filter = None 20 40 60 Backus Filter (Hz) 80 1.00 24,000 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 Water Saturation Acoustic Impedance 18,000 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 100 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 090 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 080 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 070 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 060 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 040 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 030 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 020 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 010 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 010 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 020 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 030 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 040 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 050 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 060 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 070 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 080 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 090 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 60 80 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
Zone 1 Thickness = 100 ft Backus Filter = 050 Hz 20 40 60 Backus Filter (Hz) 80 24,000 1.00 100 20 40 80 60 100 23,000 Gross Reservoir Thickness (ft) 22,000 0.83 21,000 20,000 0.67 19,000 18,000 Water Saturation Acoustic Impedance 0.50 17,000 16,000 0.33 15,000 14,000 0.17 13,000 12,000 0.00 0.0 0.1 0.2 0.3 0.4 Effective Porosity
y x depth SEISMIC IMPEDANCE y x depth PETROPHYSICAL PROPERTY RESERVOIR ASSESSMENT Upscaling • Three Steps: • Scoping at the well-log scale. • Determining upscaling sensitivity. • Predicting petrophysical properties from seismic impedance.
To Predict Petrophysical Properties from Seismic • Requires: • seismic wavelet, • seismic-derived impedance, • upscaling sensitivity relationships, and • gross thickness.
Thickness Estimation • Spectral Decomposition • to compute a Tuning Cube for the zone-of-interest. • Thickness Modeling • to derive amplitude vs thickness vs frequency relationships. • Thickness Calibration • to determine gross reservoir thickness.
y x z 3-D Seismic Volume Interpret y x z Interpreted 3-D Seismic Volume Subset y x Zone-of-Interest Subvolume z Compute y x Zone-of-Interest Tuning Cube (cross-section view) freq Animate y x Frequency Slices through Tuning Cube (plan view) freq Spectral Decomposition
1 Well # 1 0 1 mile Zone 1 08hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 10hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 12hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 14hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 16hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 18hz spectral amplitude
1 Well # 1 0 1 mile Zone 1 20hz spectral amplitude
Thickness Estimation • Spectral Decomposition • to compute a Tuning Cube for the zone-of-interest. • Thickness Modeling • to derive amplitude vs thickness vs frequency relationships. • Thickness Calibration • to determine gross reservoir thickness.
Well-Log Interpretation (Zone 1) Seismic Modeling (Zone 1) 0 1 0 50 amplitude 1 100 Two-Way Traveltime (ms) 0 shale -1 150 depth (feet) Temporal Wedge Model 200 0 6hz amplitude sand oil 10 8hz 1 20 30 Frequency (hz) 40 50 0 60 Spectral Signatures 70 0 20 40 60 80 100 Gross Pay Thickness (ft) Thickness Modeling
Thickness Estimation • Spectral Decomposition • to compute a Tuning Cube for the zone-of-interest. • Thickness Modeling • to derive amplitude vs thickness vs frequency relationships. • Thickness Calibration • to determine gross reservoir thickness.
06hz Spectral Amplitude Modeled Spectral Signatures vs Thickness 0.008 Zone 1 1 8hz amplitude 8hz 0.007 6hz amplitude 0.006 0 6hz Amplitude 0.005 WELL #1 0.004 0.003 0 1 mile 10 08hz Spectral Amplitude Frequency (hz) 20 30 40 Zone 1 10 20 30 40 50 60 70 80 90 100 Gross Reservoir Thickness (ft) Gross Reservoir Thicknessfrom 6hz and 8hz energy WELL #1 Zone 1 1 mile WELL #1 0 50 1 mile 100 Thickness Calibration
To Predict Petrophysical Properties from Seismic • Requires: • seismic wavelet, • seismic-derived impedance, • upscaling sensitivity relationships, and • gross thickness.
For Example: • If: frequencyupper = 50 hz Then: effective porosity = 0.2 • thickness = 80 ft • impedance = 15,000 Gross Thickness Impedance Zone 1 Zone 1 0 Zone 1 Thickness = 40 ft; Backus Filter = 50 Hz 50 Thickness (ft) 100 Well #1 Acoustic Impedance 1 mile 1 mile Effective Porosity Upscaling Cross-Plots Zone 1 Thickness = 80 ft; Backus Filter = 50 Hz Petrophysical Property at the Seismic Scale Acoustic Impedance Effective Porosity Note: Scale-induced uncertainty manifests itself along the axis that represents the smallest scale of measurement.