Exploration Application and Play Types
1990. "Exploration Application and Play Types", Siliciclastic Sequence Stratigraphy in Well Logs, Cores, and Outcrops: Concepts for High-Resolution Correlation of Time and Facies, J. C. Van Wagoner, R. M. Mitchum, K. M. Campion, V. D. Rahmanian
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The stratigraphic concepts we document in this book have broad application to exploration and production. The concepts provide techniques for chronostratigraphic correlation of well logs that result in (1)more accurate surfaces for mapping and facies correlation, and (2) higher-resolution chronostratigraphy for improved definition of plays, especially stratigraphic traps.
The concepts also provide techniques for lithostratigraphic correlation of well logs, thereby yielding(1) a more effective method for evaluating sandstone continuity and trend directions in reservoirs, superior to conventional correlation methods using sand stone or shale tops, (2) improved methods for precIictingpotential reservoir, source, and sealing facies away from the well, and (3) an alternative to exploration concepts such as offshore-bar reservoirs-resulting in more accurate trend prediction.
Finally, these concepts provide tools for looking at mature basins in fresh ways that result in (1) definition of new play types, opening up heavily drilled basins for new exploration, (2) improved ability to define and locate subtle, but potentially profitable, stratigraphic traps, (3) re-evaluation of producing fields to extend their lives and increase reserves, and (4) a more integrated stratigraphic framework for risking new plays. Figure 40 sununarizes potential stratigraphic- and combination structurai stratigraphic-play types associatedwith the sequences and parasequences on two different basin margins: a margin with a shelf break, referred to in Figure 40 as a shelf-edge-type margin ,and a ramp-type margin.
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Siliciclastic Sequence Stratigraphy in Well Logs, Cores, and Outcrops: Concepts for High-Resolution Correlation of Time and Facies
Application of sequence-stratigraphic analysis depends on the recognition of a hierarchy of stratal units including beds, bedsets, parasequences, parasequence sets, and sequences bounded by chronostratigraphically significant surfaces of erosion, nondeposition, or their correlative surfaces. This method of stratigraphic analysis contrasts with the use of transgressive and regressive cycles of strata for regional correlation of time and facies. Transgressive and regressive cycles have been used for regional correlation for at least 50 years. Recently, proponents of transgressive and regressive cycles, referred to as T-R units, for regional correlation have included Ryer (1983), Busch and Rollins (1984), Busch et al. (1985), and Galloway (1989a). Galloway (1989a) introduced the “genetic stratigraphic sequence,” which is a regressive depositional unit bounded by transgressive surfaces. Although he did not define it specifically, he described it as “a package of sediments recording a significant episode of basin-margin outbuilding and basin filling, bounded by periods of widespread basin margin flooding.”