Alves, Tiago Marcos ![]() |
Abstract
3D seismic volumes from SE Brazil, SE Japan and borehole data from the Ocean Drilling (ODP) and Integrated Ocean Drilling (IODP) Programs are used to demonstrate a new method to distinguish mass-transport deposits (MTDs) from confining hemipelagites, quantify MTDs internal architecture, and assess their reservoir potential or seal competence; the CDE (Contrast, Directionality, Energy) method. CDE values extracted from 3D seismic data can be tied to any ‘ground-truthed’ property of strata regardless of their depositional history, age, and lithology. The application of the CDE method is, however, dependent on seismic-data acquisition parameters and selected processing sequences, and should be independently applied to different seismic volumes. Borehole data indicate Contrast (C) to reflect MTDs lithological heterogeneity and degree of disaggregation, which increase proportionally to the absolute value of C. More uniform values of p-wave velocity (Vp) and peak shear-strength are recorded in strata with lower Contrast. Directionality (D) relates to the existence of syn- or post-depositional fabric such as compressional ridges, imbricated strata or faults. Energy (E) relates to the acoustic impedance of strata, with high-amplitude reflections correlating with strata with higher shear-strength, i.e. high Vp and shear-wave velocity (Vs) values, or with abrupt contrasts in density (‘bright spots’). This work shows that distinct values of C, D and E reflect variable degrees of vertical and horizontal connectivity in strata, the degree of internal organization in MTDs and, consequently, their seal and reservoir potential. CDE values are thus sub-divided in nine classes, which are represented in ternary plots to cover the full spectrum of MTDs and any confining strata. As a result, the data in this paper confirm that lower seal competence - and higher reservoir potential - is recorded in strata with large D or moderate CDE values.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Earth and Environmental Sciences |
Subjects: | Q Science > QE Geology |
Publisher: | The American Association of Petroleum Geologists |
ISSN: | 0271-8529 |
Last Modified: | 25 Oct 2022 08:22 |
URI: | https://orca.cardiff.ac.uk/id/eprint/52580 |
Citation Data
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