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New Petrophysical Approach in the Study of Cenozoic Coral Carbonate Rocks as Reservoirs: Example of Pleistocene Platforms, Guadeloupe, French West Indies

G. Conesa¹, E. Vernhet², D. Baden1, Y. Guglielmi¹, S. Viseur¹, and L. Marié¹
¹CEREGE UMR 7330 CNRS, Aix-Marseilles Univ., Marseille, France
²LaRGE, Antilles – Guyane University, Pointe-à-Pitre Cedex, French West Indies

The aim of our study is both to characterise Cenozoic coral carbonate rock-reservoirs, and to develop a new petrophysical approach based on step by step-measurements of P-waves propagation within rocks, at outcrop and sample scales. The Cenozoic era was chosen because scleractinian corals are a major component of subtropical to tropical sedimentary rocks and play a predominant role in carbonate anisotropy and porosity, whatever the scale. By their reef building activity, corals (1) modify their environment and thus both the sedimentary architecture and the nature of sediments, (2) create huge sedimentary architectures up to hundred metres in thickness and widespread over thousand kilometres, (3) display a high diversity of colonies shape and dimension, and of complicated reef-frameworks, (4) act on both internal fluid flows and diagenesis of carbonate sediments and rocks. Coral skeletal voids, and moldic pores produced by aragonite skeletal dissolution in the meteoric realm, represent a strong porosity. This porosity following the coral reef-frame can facilitate water circulation in carbonate rocks.

This petrophysical study is a preliminary approach in estimating initial sedimentary fabric of Cenozoic carbonate rock reservoir and their diagenetic transformation, using electronic pulse method. Resolution of the P-wave analysis needs to be improved for a better visualization of the petrographical and petrophysical properties. A scale change from metres to hundred metres will be investigated in order to extend the study to sedimentary bodies and to compare the result to seismic data. Coral assemblages and building patterns of “Grande Terre” island appear of major interest in this study as they are common in the Caribbean region within Pliocene-Pleistocene series, and some of them are widespread in the word, such as Porites.

AAPG Search and Discovery Article #120034©2012 AAPG Hedberg Conference Fundamental Controls on Flow in Carbonates, Saint-Cyr Sur Mer, Provence, France, July 8-13, 2012