Agreement DE-FC26-02NT15342, Seismic Evaluation of ...

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associated with the channel feature becomes pronounced. Figure 81 shows the pseudo well logs, wavelet and synthetic trace as well as Zoeppritz modeled AVO response for the fluid intervals. The AVO response for the brine case is a small trough, which decreases to no trough or peak. The hydrocarbon saturated reservoir cases show troughs associated with the reservoir top that decrease with offset. The oil and 50% gas fluid phases appear to have the strongest impact on the seismic amplitudes. Observations of these models show that the channel fill compartments can be imaged even if they are brine saturated. Connected amalgamated channel bodies produce a more continuous signature than that of a non-amalgamated channel body represented by an isolated channel model. But the details of where the fluid barriers occur cannot be accurately defined. Stratigraphic pinch-outs can be imaged but not clearly defined due to tuning effects (thickness < ¼ wavelength). These features may be resolved by using higher frequency wavelets. Lower Yellow reservoir character The Lower Yellow reservoir interval was originally interpreted to be sheet sand (Hilterman, 2001, Meckel et al., 2001). The Lower Yellow Sand is rectangular in shape and has dimensions of ~3.2-4.8 km (Weimer et al., 2004). The sand is 15-18 m thick with an estimated aspect ratio 250:1. It produced 62 BOPD and 62 MCFGPD from six wells in 2002 (Weimer et al., 2004). The Lower Yellow reservoir was interpreted to have a channel cutting through it connecting the two reservoirs. Sheet sands are deposited from decelerating flows at the termini of channels. Therefore, one major problem with the interpretation is that it is difficult to distinguish between sheet sands and channel deposits. They have good continuity and connectivity, high aspect ratios, and high permeability and porosity. One possible property to differentiate the two is aspect ratio because it is much higher for channel sands. The contact between sheets and channel sands is transitional, which puts sheets in connection with channels updip and has potential for fluid migration in the reservoir. (Weimer et. al, 2004) Another challenge associated with sheet sands is differentiating amalgamated (non-layered) from nonamalgamated (layered) sand. Moving downdip, a transition from amalgamated to nonamalgamated sheets often occurs. The log signature (Figure 81) has a sharp base and top and has a blocky to serrate pattern, which is consistent with the character of sheet sands in Weimer (2004). Generally the seismic signature of a sheet sand is expressed by one single seismic event. The seismic signature (Figure 82) shows good continuity with little change in the wavelet. Interplay of different stacking patterns can result in different seismic signatures. In the intraslope basin setting the reflections tend to thin out or lap out against another surface. The AVO response in figure 83 shows a decrease in amplitude with offset. Agreement DE-FC26-02NT15342, Seismic Evaluation of Hydrocarbon Saturation 98
Figure 82. Log signature includes gamma, resistivity, porosity, P-wave, s-wave and density as well as synthetic seismic stacked AVO response using Zoeppritz modeling with a 6000 m offset. Gamma shows blocky serrated signature with sharp top and base contacts. Figure 83. Seismic response of the Lower Yellow reservoir interval shows the reservoir top corresponding with the trough of the wavelet in post stack data. Agreement DE-FC26-02NT15342, Seismic Evaluation of Hydrocarbon Saturation 99
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June 29, 2006 Seismic Evaluation of
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Abstract: During this last quarter
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Ursa Data .........................
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Figures: Figure 1. Relationship of
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Figure 38. Schematic of geometry an
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Figure 73. The extracted wavelet an
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Executive Summary: In this joint pr
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Results and Discussion Introduction
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Inversion of Sw and porosity from s
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saturation from seismic data. Valid
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The Lagrange function (5) has a sad
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ρ ma − ρ + ( ρ w − ρ g ) ×
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With a water saturation log calcula
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Figure 11. permeability versus poro
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Figure 13. Measured dry and brine s
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Figure 15. The HP (deep) sands have
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pressure-porosity relations. The n
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Figure 19. measure dry and brine sa
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Relations between Sw, porosity, and
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Figure 21. An example realization o
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otherwise the seismic properties we
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correctly reproduce those found in
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study of field data from the Teal S
Page 47 and 48: Figure 30. Spectral decomposed pres
Page 49 and 50: (Adapted from CSM Slope and Basin C
Page 51 and 52: Figure 34. Sequence stratigraphic f
Page 53 and 54: Figure 36. Schematic depiction of c
Page 55 and 56: Figure 38. Schematic of geometry an
Page 57 and 58: Figure 40. Middle slope channel (Ad
Page 59 and 60: Figure 43. Amalgamated sandstone sh
Page 61 and 62: CHANNEL AXIS SINGLE STORY CHANNEL C
Page 63 and 64: MEDIAL LEVEE/OVERBANK 7.62 cm Figur
Page 65 and 66: L1054 L1041 • Ursa Well A4 Green=
Page 67 and 68: 1.9 miles 37 ft Fizz 19 ft Oil 4.0
Page 69 and 70: esults in shifts followed by subsid
Page 71 and 72: Figure 55. Schematic of depositiona
Page 73 and 74: 4 miles 1.5 s 2 s 3 s Hydrocarbon I
Page 75 and 76: In addition to comparing calculated
Page 77 and 78: Figure 61. Shear velocity trend for
Page 79 and 80: each reservoir interval modeled. Th
Page 81 and 82: Figure 65. Histograms of frequency
Page 83 and 84: the pressure trends were analyzed,
Page 85 and 86: P Impedance Model Synthetic 2 -D Mo
Page 87 and 88: Above Magenta reservoir model The A
Page 89 and 90: Figure 73. The extracted wavelet an
Page 91 and 92: saturation and 50% gas saturation.
Page 93 and 94: Figure 77. The amalgamated channel
Page 95 and 96: Figure 79. Channel complex model 2
Page 97: Figure 81. AVO stack and gathers fo
Page 101 and 102: Figure 85. Extracted wavelet and mo
Page 103 and 104: Figure 87. Amalgamated sheet sand m
Page 105 and 106: Figure 89. Pseudo logs, wavelet, sy
Page 107 and 108: Figure 90. Medial basin floor chann
Page 109 and 110: Figure 92. Pseudo logs, wavelet, sy
Page 111 and 112: Figure 94. The post stack seismic e
Page 113 and 114: Figure 96. Statistically extracted
Page 115 and 116: Figure 98. The proximal levee overb
Page 117 and 118: Figure 99. The response of the prox
Page 119 and 120: Figure 101. The pseudo log, wavelet
Page 121 and 122: Figure 102. The distal levee overba
Page 123 and 124: Figure 104. The complex well log ba
Page 125 and 126: then scaled to the model data by mu
Page 127 and 128: Figure 107. The Ursa log displays g
Page 129 and 130: Figure 109. Composite reflection co
Page 131 and 132: Conclusions One of the main conclus
Page 133 and 134: Table 5 Summary of the model facies
Page 135 and 136: REFERENCES Alford, R. M., Kelly, K.
Page 137 and 138: Gardner, M. H., Anderson, D. A., Bo
Page 139 and 140: Mahaffie, M.J., 1994, Reservoir cla
Page 141 and 142: Rothman, D.H., Grotzinger, J.P., Fl
Page 143 and 144: Vail, P., 1977, Seismic Stratigraph
Page 145 and 146: downlap (Mtchum, 1977): A base-disc
Page 147 and 148: direction and downlap onto the tran
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Agreement DE-FC26-02NT15342, Seismi
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APPENDIX E: VALUES USED FOR RESERVO
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