H. Sa’adatnia; A. Javaherian; I. Abdollahi Fard; M. R. Ghassemi
Abstract
One of the duties of seismic interpreter is interpretation of the geological structures likely to be found at deeper levels. Such constructions form a key to the understanding of regional tectonics and they often play a vital role in industry. The exploration for oil and gas in particular ...
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One of the duties of seismic interpreter is interpretation of the geological structures likely to be found at deeper levels. Such constructions form a key to the understanding of regional tectonics and they often play a vital role in industry. The exploration for oil and gas in particular requires the best possible control on underground structures in order to locate drill holes for exploration investigation or for producing wells. Because the primary data are always incomplete and may be in part contradictory, the final interpretation should be at least geometrically validated. A powerful and independent test for the validity of a structural interpretation is the restoration of the structure to the shape it had before deformation. Restoration is a fundamental test of the consistency of the interpretation. It is best described by transformation equations which incorporate rigid translation and rotation plus deformation. A map or cross section can usually be restored by methods based on more than one kinematic model, and different methods will produce somewhat different restored geometries. It follows that any given restoration doesn’t necessarily represent the exact pre-deformation geometry. The internal consistency of the restoration by any technique constitutes a validation of the interpretation. In this study, the main aim is introducing the balancing of seismic interpretation and its application to decrease the errors of interpretation. For this purpose, length and area balancing were done at a sample seismic cross section from 3D seismic data of two oilfields at the East of Khuzestan (SW Iran). As a result, the primary interpretation was corrected and finally the corrected interpretation was compared with primary interpretation. For balancing of seismic sections in this area, the flexural slip technique is selected as optimum technique through testing line-length, vertical simple shear and flexural slip techniques.
A.R. Javaheri Niestanak; A. Javaherian; N. Amini
Abstract
Coherency attribute is one of the proper tools in interpretation of structural discontinuities and stratigraphy features in 3-D seismic data. Coherency measurements in three dimensions discuss trace-to-trace similarity and therefore represent interpretable changes in these cases. The similar traces are ...
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Coherency attribute is one of the proper tools in interpretation of structural discontinuities and stratigraphy features in 3-D seismic data. Coherency measurements in three dimensions discuss trace-to-trace similarity and therefore represent interpretable changes in these cases. The similar traces are mapped with high coherence coefficients while anomalies and discontinuities have low coherence coefficients. Coherency attribute shows evaluation criterion of lateral changes in the seismic response, caused by variation in structure, stratigraphy, lithology, porosity and the presence of hydrocarbon. Output of this attribute is a coherence cube which illustrates structural discontinuities and stratigraphy features with higher resolution. In this paper, the application of two conventional coherency attributes based on eigenstructure and crosscorrelation for detection of faults in 3-D synthetic seismic data and actual seismic data is presented.
Considering the experimental results, this method has an appropriate response to low SNR for 3-D synthetic models and 3-D actual data. In addition, the comparison of eigenstructure -based coherency attribute method with crosscorrelation-based coherency attribute method indicates the former has higher resolution for detection faults than the latter.
A. Gholami; M. Javaherian
Abstract
In experimental sciences we often need to solve inverse problems. That is, we want to obtain information about the internal structure of a physical system from indirect noisy observations. Information about the errors in the observations is essential to solve ...
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In experimental sciences we often need to solve inverse problems. That is, we want to obtain information about the internal structure of a physical system from indirect noisy observations. Information about the errors in the observations is essential to solve any inverse problem; otherwise it is impossible to say when a feature ‘fits the data’. In practice, however, one seldom has a direct estimate of the data errors. Here, we exploit the trade-off between data prediction and model or data structure to determine model based estimates of the noise characteristics from a single realization of the data. Noise estimates are then used to characterize the set of reasonable models that fit the data. By intersecting set of prior model parameter constraints with the set of data fitting models, we obtain a set of models that fit the data and are in agreement with prior constraints. This prior information can also be used to set bounds on the bias. We illustrate our methods with a synthetic example of vertical seismic profiling (VSP).
