Multicomponent seismic detection and interpretation of salt and salt dissolution
Zandong Sun, R. James Brown
Geophysical expressions of salt and salt dissolution are extremely significant for the explorationist for a number of reasons; salt dissolution may develop and affect hydrocarbon traps in the following ways: 1) reservoir facies can be structurally closed over the edges of residual salt bodies (Figure 1), or over salt remnants as a result of progressive leaching of salt (Figure 2); 2) reservoir facies can be stratigraphically trapped where preferentially deposited in salt-dissolution lows (Figure 3) or highs; 3) reservoir facies can be stratigraphically trapped where preferentially preserved in a salt-dissolution low (Figure 4); 4) drape across a salt remnant can be misinterpreted on seismic data as either drape across a reef or as being indicative of basement anticlinal structure, for example Wabamun salt and Leduc reef (see Figure 5); 5) salt can either enhance or degrade the seismic signature of an underlying reef (see Figure 6); 6) a low-velocity salt interval can be misinterpreted as a porous reservoir (for example, Wabamun salt and Nisku porosity); 7) salt dissolution usually causes brecciated and faulted zones which can allow oil to leak out of potential traps.
The objectives of this study are to gain an understanding of salt and salt dissolution features, to develop the capability to identify salt and salt dissolution on conventional and multicomponent seismic sections and in gravity data, and to undertake the analysis and interpretation of such a geophysical dataset.
This paper constitutes an M.Sc. thesis proposal to be carded out by the first author under the supervision of the second author. The specific area of investigation will depend on the seismic and gravity data available.