Seismic Stratigraphy Case Study

Conceptual models and real three-dimensional (3-D) seismic data show that in progradational carbonate platform margin and slope deposits of the Kingdom Abo reservoir of the Permian basin, west Texas, primary seismic reflection events do not necessarily follow clinoformal geologic-time surfaces. The seismic frequency content of the data controls the dip and architecture of seismic reflection events. High-frequency seismic data tend to follow thinner, time-bounded clinoform depositional elements (time-stratigraphic units), whereas low-frequency seismic data tend to image thicker, low-angle lithofacies units (time-transgressive units). In seismic data of moderate frequency, both clinoform units and flat lithofacies units are imaged, creating complex interference patterns that are difficult to interpret.

Experiments with models and real data demonstrate that seismic data can be selectively filtered in the signal bandwidth to help distinguish time-stratigraphic units from lithostratigraphic units. Selective filtering alters the dominant frequency of the data to match a desired scale of geologic objects. If there are enough high-frequency components in the seismic data, true clinoform stratigraphy can be imaged even if the data are dominated by lower frequency components.

Seismic modeling of outcrop of the Abo sequence in Apache Canyon, Sierra Diablo, west Texas, indicates that a dominant frequency of 100 Hz is needed to recover true clinoform stratigraphy using seismic data. The interpretation of available 3-D seismic data can only partially distinguish time-stratigraphy from lithostratigraphy because of the lack of frequency components greater than 70 Hz in the data. Application of this outcrop model in seismic modeling avoids interpretational pitfalls that can occur if the dominant frequency of the seismic data is not matched to the unit thicknesses that need to be resolved.

The 2e of Seismic Stratigraphy and Depositional Facies Models summarizes basic seismic interpretation techniques and demonstrates the benefits of integrated reservoir studies for hydrocarbon exploration. Topics are presented from a practical point of view and are supported by well-illustrated case histories. The reader is taken from a basic level to more advanced study techniques. The presented modern geophysical techniques allow more accurate prediction of the changes in subsurface geology. Dynamics of sedimentary environments are discussed their relation to global controling factors, and a link is made to high-resolution sequence stratigraphy.

The interest in seismic stratigraphic techniques to interpret reflection datasets is well established. The advent of sophisticated subsurface reservoir studies and 4D monitoring for optimizing the hydrocarbon production in existing fields demonstrate the importance of the 3D seismic methodology. The added value of reflection seismics to the petroleum industry has clearly been proven over the last few decades. Seismic profiles and 3D cubes form a vast and robust data source to unravel the structure of the subsurface. Larger offsets and velocity anisotropy effects give access to more details on reservoir flow properties like fracture density, porosity and permeability distribution. Elastic inversion and modeling may tell something about the change in petrophysical parameters. Seismic investigations provide a vital tool for the delineation of subtle hydrocarbon traps, and they are the basis for understanding the regional basin framework and the stratigraphic subdivision. Seismic stratigraphy combines two very different scales of observation: the seismic and well control. The systematic approach applied in seismic stratigraphy explains why many workers are using the principles to evaluate their seismic observations.

  • Discusses the link between seismic stratigraphic principles and sequence stratigraphy
  • Provides techniques for seismic reservoir characterization as well as well control
  • Analyzes inversion, AVO and seismic attributes

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