Fault imaging of Hibernia 3-D seismic data using edge-detection and coherency measures

Coherency cube” and fault detection technologies have evolved rapidly in recent years as important tools for seismic interpretation. The following paper, developed as a joint project between investigators at Memorial University and the University of Calgary, compares several of the fault detection methods for data from Hibernia field. The results, which are outlined in detail in the Memorial University M.Sc. thesis of Nicholle Carter, support the usefulness of coherency measures prescribed by Marfurt et al. (1998). INTRODUCTION The development of the “coherence cube” and related technologies during recent years has proven to be a valuable interpretive aid for fault detection as evidenced by Nissen et al. (1999). Following the introduction of The Coherence Cube by Bahorich and Farmer (1995) for the interpretation of 3-D seismic data from offshore Trinidad, several papers have described the development and application of algorithms for detecting fault discontinuities. One of these, the paper by Marfurt et al. on 3-D seismic attributes using a semblance-based coherency algorithm received the award for Best Paper in Geophysics in 1998, a testimony to the importance of this technology. The detection of faults in offshore seismic exploration has been enhanced by use of algorithms from two families – those that measure coherency and those that detect discontinuities or “edges” by differencing. (Actually it is more accurate to say that these algorithms reveal a lack of coherency in order to detect faults.) In this study, we apply such “uncoherency” methods to depth migrations from Hibernia field and we compare results for both synthetic and real data. More details of our study are found in the recent M.Sc. thesis of Nicholle Carter of Memorial University of Newfoundland (accepted, September 1999). HIBERNIA GEOLOGY Seismic methods play a key role in exploration and reservoir characterization of offshore Newfoundland’s Hibernia oil field, potentially one of North America’s most important offshore sources of crude oil. Figure 1 gives the geographic location of the field on the East Coast of Canada. As shown in Figure 1, Hibernia field, located about 315 km southeast of St. John’s, Newfoundland, is part of the Jeanne d’Arc Basin which includes a large number of extensional faults. A detailed geological picture of this basin is being developed with the use of 3-D seismic surveys. A Hibernia 3-D seismic survey was made available to the Memorial University Seismic Imaging Consortium (MUSIC) by the Hibernia Management and Development Corporation (HMDC) for research into imaging algorithms.