The Carbonate Analogs Through Time (Catt) Hypothesis and the Global Atlas of Carbonate Fields—A Systematic and Predictive Look at Phanerozoic Carbonate Systems
Published:January 01, 2008
James R. Markello, Richard B. Koepnick, Lowell E. Waite, Joel F. Collins, 2008. "The Carbonate Analogs Through Time (Catt) Hypothesis and the Global Atlas of Carbonate Fields—A Systematic and Predictive Look at Phanerozoic Carbonate Systems", Controls on Carbonate Platform and Reef Development, Jeff Lukasik, J.A. (Toni) Simo
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The Carbonate Analogs Through Time hypothesis states that “high-confidence, age-specific predictive models for carbonate systems and for reservoir occurrence, composition, stratal attributes, and reservoir properties can be developed by summing the ambient conditions of the carbonate processes and Earth processes at any geologic age.” We term these models age-sensitive patterns or themes. The hypothesis is built upon the cumulative body of knowledge that demonstrates carbonate processes (biotic evolution and mineralogic variation) and Earth processes (tectonics, climate, eustasy, ocean chemistry, and ocean circulation) have varied differentially throughout Phanerozoic time. The concepts of the stratigraphic hierarchy and the Sloss sequences are employed to temporally define and anchor age- specific predictive models. Age-based themes correspond to second-order supersequence scale of stratal packages, and these are fixed in geologic time (Ma). Two products developed are the Phanerozoic Carbonate Trends Chart and the Global Atlas of Carbonate Fields.
The Carbonate Analogs Through Time hypothesis defines an approach for developing systematic evaluations and predictive models of Phanerozoic carbonate systems and reservoirs for use in exploration, development, and production businesses. Exploration geoscientists employ a host of concepts, tools, and data to develop predictive models for occurrence and quality of fields and reservoirs. However, as exploration successes decrease, alternative approaches are needed to refresh the exploration mindset. The CATT hypothesis and approach represent a basis for developing an alternative mindset for exploration for carbonate reservoirs. It provides a thought-provoking perspective on known occurrences of carbonate reservoirs, and offers a different way of thinking about predicting where undiscovered carbonate reservoirs may exist.
Reservoir engineers require detailed geology-based reservoir parameters for simulations of reservoir / field performance. Such simulations form the bases for field development/depletion plans that carry with them implications of huge capital and operating expense. Thus, it is imperative to provide the best possible input to simulation so that investments are optimal. Typically, the input, if not derived directly from data collected within a field under development, is obtained from “analog” fields. Thus, choosing the most appropriate analog is a critical task. We contend that this approach provides the conceptual basis for choosing the most appropriate analogs for development and production-based reservoir characterization. Further, this approach provides a framework or context for the systematic organization and evaluation of the concepts, facts, and carbonate-reservoir case studies one encounters throughout a career.
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Controls on Carbonate Platform and Reef Development
Carbonate platforms and reefs emerge, grow and die in response to intrinsic and extrinsic mechanisms forced primarily by tectonics, oceanography, climate, ecology and eustasy. These mechanisms, or controls, create the physical, biological and chemical signals accountable for the myriad of carbonate depositional responses that, together, form the complex depositional systems present in the modern and ancient settings. If we are to fully comprehend these systems, it is critical to ascertain which controls ultimately govern the “life cycle” of carbonate platforms and reefs and understand how these signals are recorded and preserved. Deciphering which signals produce a dominant sedimentological response from the plethora of physical and biological information generated from superimposed regional to global-scale controls is critical to achieving this goal. With this understanding, it may be possible to extract common time- and space-independent depositional responses to specific mechanisms that may, ultimately, be used in a productive sense. Extensive research on a wide variety of carbonate platform and reefal systems in the past few decades has provided the foundation and understanding necessary to take carbonate research to a new level. With assistance from rapidly advancing computer software and an increasing use of cross-disciplinary integration, carbonate research is shifting from description and morphological analysis towards a science that is more focused on the assessment of process and genetic relationships. The aim of this special publication is to present a cross section of recent research that shows this evolution from a variety of perspectives and scales using examples distributed throughout the Phanerozoic.