Seismic attributes
| Exploring for Oil and Gas Traps | |
| |
| Series | Treatise in Petroleum Geology |
|---|---|
| Part | Predicting the occurrence of oil and gas traps |
| Chapter | Interpreting 3-D seismic data |
| Author | Geoffrey A. Dorn |
| Link | Web page |
| Store | AAPG Store |
Attributes are measurements based on seismic data such as polarity, phase, frequency, or velocity. Horizon attributes were first used in the mid-1980s for interpreting fault traces on reservoir horizons. Since then there has been an explosion in the number of attributes that can be generated and displayed in 3-D interpretation systems. New attributes are added to the list regularly. Because software providers frequently use different names for the same attribute, and since some of the names are rather obscure, it can be very difficult be sure what each attribute represents.
Grouping attributes
At this time, no general reference includes a complete list of the attributes that can be created. One approach[1] to organizing the attributes is based on whether they are related to the following:
- Time
- Amplitude
- Phase
- Frequency in the seismic data
An alternative approach might be to group them into these categories:
- Horizon attributes (measures of the data that occur along a 3-D surface through the seismic volume)
- Volume attributes (measures of the data that occur over an interval of time through the seismic volume)
Attribute meanings
The meaning and use of some attributes can be quite straightforward. The reflection amplitude at a horizon can, under the correct circumstances, be related to porosity or net pay in a reservoir interval. With other attributes the physical interpretation of a variation in attribute value is somewhat more obscure. For example, arc length (also call reflection heterogeneity) is a measure of the length of the wiggle trace over a specified interval (technically, it is an approximation of the line integral of the trace over the interval). This measure is affected by amplitude, frequency, and the length of the interval. Associating a variation in arc length with a physical change in the geology is possible, but it can be more challenging.
Attribute interpretation
Attributes are used for both qualitative and quantitative interpretation. An example of qualitative interpretation would be to use maps of dip magnitude, dip azimuth, or residual structure to interpret detailed fault trace patterns on a horizon. An example of quantitative interpretation would be an attempt to correlate attributes with reservoir properties measured in the borehole. A large number of papers illustrating both applications of horizon and volume attributes are published each year in various professional journals. Examples of applications to structural interpretation include Brede and Thomas[2] Denham and Nelson[3] Dalley et al.[4] Rijks and Jauffred[5] and Dorn et al.[6] Stratigraphic interpretation from attribute maps is discussed in Enachescua[7][8] Reymond and Stampfli[9] and Dorn.[10] Examples of reservoir characterization from attributes include Dorn et al.[6] and Brown.[1]
See also
References
- ↑ 1.0 1.1 Brown, A., R., 1999, Interpretation of Three-Dimensional Seismic Data, 5th ed.: AAPG Memoir 42, 525 p.
- ↑ Brede, E., C., Thomas, S., W., 1986, Interactive fault mapping: a case study: The Leading Edge, vol. 5, no. 9, p. 1262–1272., 10., 1190/1., 1439303
- ↑ Denham, J., I., Nelson, H., R. Jr., 1986, Map displays from an interactive interpretation: Geophysics, vol. 51, p. 1999–2006., 10., 1190/1., 1442055
- ↑ Dalley, R., M., Gevers, E., C., A., Stampfli, G., M., Davies, D., J., Gastaldi, C., N., Ruijtenberg, P., A., Vermeer, G., J., O., 1989, Dip and azimuth displays for 3D seismic interpretation: First Break, vol. 7, no. 3, p. 86–95.
- ↑ Rijks, E., J., H., Jauffred, J., C., E., M., 1991, Attribute extraction: an important application in any detailed 3-D interpretation study: The Leading Edge, vol. 10, no. 9, p. 11–19., 10., 1190/1., 1436837
- ↑ 6.0 6.1 Dorn, G., A., Tubman, K., M., Cooke, D., O'Connor, R., 1996, Geophysical reservoir characterization of Pickerill Field, North Sea, using 3-D seismic and well data, in Weimer, P., Davis, T., eds., Applications of 3-D Seismic Data to Exploration and Production: AAPG Studies in Geology 42, p. 107–121.
- ↑ Enachescu, M., E., 1993a, Amplitude interpretation of 3-D reflection data: The Leading Edge, vol. 12, no. 6, p. 678–685., 10., 1190/1., 1436956
- ↑ Enachescu, M., E., 1993b, Three-dimensional seismic imaging of a Jurassic paleodrainage system: 1993 SEG Summer Research Workshop on 3-D Seismology, Abstracts, p. 292–298.
- ↑ Reymond, B., A., Stampfli, G., M., 1994, Sequence stratigraphic interpretation of 3D seismic data offshore Louisiana—a case study: First Break, vol. 12, no. 9, p. 453–462.
- ↑ Dorn, G., A., 1998 Modern 3-D seismic interpretation: The Leading Edge, vol. 17, no. 9, p. 1262–1272., 10., 1190/1., 1438121
External links
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