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![May 1999
21 BTC
Dynamic Elastic Properties
v Poisson’s Ratio
G Shear Modulus
E Young’s Modulus
Kb Bulk Modulus
Cb Bulk Compressibility
(with porosity)
Lateral strain 1/2 (DTS / DTC) 2
– 1
Longitudinal strain (DTS / DTC) 2
– 1
Applied stress
pb
Shear strain
DTS 2
Applied uniaxial stress
Normal strain
2G (1 + v)
Hydrostatic pressure
Volumetric strain
1 4
DTC2 3DTS2
[ ]x a
Volumetric deformation
Hydrostatic pressure
1
Kb
pb
Note: coefficient a = 1.34 x 1010
if pb in g/cm3
and DT in µs/ft.](https://image.slidesharecdn.com/lecturedsi-250204035234-c8d6acc0/85/Lecture_DSI-21-320.jpg)
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Lecture_DSI................................
- 1.
- 2. May 1999 2 BTC WavePropagation At Rest Compressional Shear
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- 4. May 1999 4 BTC Fast Formation— Monopole Compressional: 76 sec/ft Shear: 139 sec/ft Fluid: 200 sec/ft Borehole diameter: 10 in. Time: 1 msec Source: 12-kHz monopole Compressional body wave Compressional head waves Shear head wave Shear body wave 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 0.5 1.0
- 5. May 1999 5 BTC SoftFormation — Monopole Wellbore Head wave Fluid wave Omnidirectional source Formation Compressional wave Shear wave Compressional wave Stoneley wave
- 6. May 1999 6 BTC DSITransducer Mud Mud Borehole Propagation Displacement Flexural Wave Transmitter
- 7. May 1999 7 BTC Slow Formation— Monopole Compressional:157 sec/ft Shear: 300 sec/ft Fluid: 200 sec/ft Borehole diameter: 12 in. Time: 2 msec Source: 12-kHz monopole Compressional body wave Compressional head wave Compressional head wave Fluid head wave 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 0.5 1.0 Fluid modes Shear head wave absent
- 8. May 1999 8 BTC SoftFormation — Dipole Wellbore Head wave Flexural wave Directional source Formation Compressional wave Shear wave Compressional wave Flexural wave Shear wave
- 9. May 1999 9 BTC Slow Formation— Dipole Compressional:157 sec/ft Shear: 300 sec/ft Fluid: 200 sec/ft Borehole diameter: 12 in. Time: 2 msec Source: 12-kHz monopole 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0 0.5 1.0 Shear body wave Compressional body wave Flexural mode
- 10. May 1999 10 BTC DipoleWaveforms—Fast Formation Shear Flexural Mode
- 11. May 1999 11 BTC DSITool Cartridge Receiver section Isolation joint 9 ft to monopole transmitter 11 ft to upper dipole transmitter 11.5 ft to lower dipole transmitter Transmitter section 16.5 ft 3.5 ft 18 ft 13 ft 42 in. 6 in. Principal tool combinations • AIT* Array Induction Imager Tool • ARI* Azimuthal Resistivity Imager tool • Auxiliary Measurements Sonde • Compensated Neutron Log • FMI* Fullbore Formation MicroImager tool • Gamma Ray • General Purpose Inclinometry Tool (GPIT) • IPL* Integrated Porosity Lithology tool • Phasor* Induction tool • UBI* Ultrasonic Borehole Imager tool • USI* UltraSonic Imager tool
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- 13. May 1999 13 BTC STCComputation Varying moveout Varying time
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- 15. May 1999 15 BTC STCPlanes 0.5 to 1.5 kHz 1 to 2 kHz 800 100 0 14,000 0 14,000 Slowness (sec/ft) Time (sec) Time (sec)
- 16. May 1999 16 BTC LogQuality Indicators Poisson's Ratio .25 .50 Gamma Ray Caliper 6 16 0 100 Delta-T Comp. 100 200 Delta-T Shear 0 1. 1. 0 100 500 Dtc Coherence Dts 10200 10250 10300 10350 Slowness Time Plane Projection
- 17. May 1999 17 BTC Slowness Bias BiasAfter Filtering Bias Before Filtering Flexural Mode Slowness Formation Shear Slowness STC Filter Response Filtered Amplitude Spectrum Unfiltered Amplitude Spectrum Noise Amplitude Spectrum Frequency (kHz) Frequency (kHz) 320 300 1 0.5 0 0 2 4 6 8 10 0 2 4 6 8 10 A m p l i t u d e . S l o w n e s s ( µ s / f t )
- 18. May 1999 18 BTC BoreholeCompensation Receiver Array Pseudo Transmitter Array Formation Interval Measured
- 19. May 1999 19 BTC BoreholeCompensation Receiver subarrays Pseudo transmitter subarrays Formation interval measured Common receiver position VP/VS - STC 0 106 psi 4 VP/VS - MPS 0 106 psi 4 RHOB 1.7 (G/C3) psi 2.7 NPHI 60 (PU) 0 SGR 0 (GAPI) 120 1:300 Ft CALI 12 (IN) 20 DTCO-BHC-STC 500 (US/F) 100 DTCO-BHC-MSP 500 (US/F) 100 DTSM-UDP-CRC-STC 500 (US/F) 100 DTSM-UDP-CRC-MSP 500 (US/F) 100 x700 x650 x600
- 20. May 1999 20 BTC Applications •Mechanical property analysis — sanding analysis — fracture height — wellbore stability • Formation evaluation — gas detection — fractures — permeability • Geophysical interpretation — synthetic seismograms — VSP — AVO
- 21. May 1999 21 BTC DynamicElastic Properties v Poisson’s Ratio G Shear Modulus E Young’s Modulus Kb Bulk Modulus Cb Bulk Compressibility (with porosity) Lateral strain 1/2 (DTS / DTC) 2 – 1 Longitudinal strain (DTS / DTC) 2 – 1 Applied stress pb Shear strain DTS 2 Applied uniaxial stress Normal strain 2G (1 + v) Hydrostatic pressure Volumetric strain 1 4 DTC2 3DTS2 [ ]x a Volumetric deformation Hydrostatic pressure 1 Kb pb Note: coefficient a = 1.34 x 1010 if pb in g/cm3 and DT in µs/ft.
- 22. May 1999 22 BTC IMPACT Log 0p.u. 100 Combined Model Min. Safe Mud Weight/Shear Max. Safe Mud Weight/Shear Max. Safe Mud Weight/Tensile Mud Weight Poisson's Ratio Young's Modulus Shear Modulus 0 106 psi 10 0 106 psi 5 0 5 Hole Profile Depth –25 in. 25 1000 ft
- 23. May 1999 23 BTC SandingModel Diagram Pe, Far Field Pressure Pp, Pore Pressure Far Field Stresses Flow r = Pw (1—) y x Pw r
- 24. May 1999 24 BTC vp/vs versustc 3.5 3.0 2.5 2.0 1.5 Anthydrite 50 100 150 ²tc
- 25. May 1999 25 BTC vp/vs versustc 3.0 2.5 2.0 1.5 50 100 150 ²tc vp/vs Unconsolidated sediments Shales 40 35 30 90 80 70 Sxo 60 50 40 Gas ø W e t s a n d s t o n e s Dry gas Wet Dry (or gas sandstones 20 10 Limestone Anhydrite Dolomite Salt Quartz
- 26. May 1999 26 BTC Fracture Evaluation STONELEYWF1 0 (US) 20000 0 (GAPI) 150 0 0.15 Gamma Ray Stoneley Ref. Coef. 2 (IN) 7 Hole Diameter 600 700 800
- 27. May 1999 27 BTC Stoneley Energy GammaRay Resistivity Density-Neutron Stoneley Energy Differential Energy 6300 6400 7100
- 28. May 1999 28 BTC Poisson’sRatio— 0 0.1 0.2 0.3 0.4 0.5 Poisson’s Ratio = Vp / Vs 2 - 2 2 Vp / Vs 2 - 2
- 29. May 1999 29 BTC Poisson’sRatios Podio et al. (1968) Green River Shale 0.22–0.30 Hamilton (1975) Shallow Marine Sediments 0.45–0.50 Gregory (1976) Consolidated Sediments Brine Saturated 0.20–0.30 Gas Saturated 0.20–0.14 Domenico (1976) Synthetic Sandstone Brine Saturated 0.41 Gas Saturated 0.10 Domenico (1977) Ottawa Sandstone Brine Saturated 0.40 Gas Saturated 0.10 Poisson’s Ratios Sediment Reference
- 30. May 1999 30 BTC AVOResponse HYDROCARBONS POROSITY MATRIX SHALE SPECIAL MINERAL OFFSET ANGLE (DEG) 0 2 4 6 8 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 GRADIENT INTERCEPT PRODUCT NOR POLARITY 2400 2500 2600 2700 4.8 4.5 4.3 4.0 3.8 3.5 3.3 3.0 2.8 2,5 2.3 2.0 1.8 1.5 1.3 1.0 0.8 0.5 0.3 1 1 2 1 5 0 5 0
- 31.
- 32. May 1999 32 BTC DSIDipole Shear Sonic Imager • Monopole compressional and dipole shear measurements provide sonic data in hard and soft formations • Applications — Mechanical property analysis — Formation evaluation — Geophysical applications