Taphofacies and Petrofacies Theoretical Marine Models Applied to the Coquina of the Amaral Formation (Lusitanian Basin, Portugal)

Gustavo Gonçalves Garcia,Rui Pena Dos Reis,Maria Helena Paiva Henriques,Antônio Jorge Vasconcellos Garcia,Rafael Mendes Marques

doi:10.3390/jmse9121319

Gustavo Gonçalves Garcia, Rui Pena Dos Reis + Show 3 more

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https://doi.org/10.3390/jmse9121319

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Abstract

The Amaral Formation has a wide geographic distribution within the Lusitanian Basin, at the western Iberian Margin (Portugal). The different depositional contexts for this unit enabled the distinction of three sectors: lagoon, lagoon-barrier, and marine-distal. The integration of the evolutionary taphonomic analysis of its fossil assemblages with the analysis of multiscale properties through the CAMURES methodology (Multiscale Reservoir Characterization) allowed the application of a methodology for the classification of coquina which was previously developed for the Morro do Chaves Formation (Sergipe–Alagoas Basin, Brazil). Here, it was adapted according to the complexity of the Amaral Formation deposits. The classification of ten taphofacies, in association with four lithofacies, allowed the definition of 84 petrofacies, based on the nature of the sedimentary and taphonomic processes. The relationship between the structural context, the systems tracts, the diversity of the fossil record, the classification of taphofacies and petrofacies, and the understanding of vertical and lateral variations of the sediments’ deposition within the unit support the construction of geological and theoretical models for coquina deposits. These models will allow for prediction of the spatial distribution of facies in other coquina analogous hydrocarbon reservoirs, as well as specifying the delimitation of reservoir zones for 3D geocellular modeling and flow simulation of hydrocarbon-producing reservoirs, thus improving predictive analyses.

Highlights

The need for increasing accuracy and effective predictive models is an important challenge faced by the oil industry, which seeks to understand the distribution of permoporous spaces in hydrocarbon reservoirs
The integrated analysis involving the characterization of petrofacies and the taphonomic approach based on the evolutionary taphonomy concepts and methods [3,4], with the application of the Multiscale Characterization Methodology of Reservoirs—CAMURES [2,5], represents a new pathway for the development of predictive modeling of reservoir quality
By improving the understanding of the lateral and vertical facies variations of the coquina deposits, this integration allows us to expand the knowledge about the genesis of paleoenvironmental models, as well as the 3D geocellular models of coquina facies, which underlie the fluid flow simulation in hydrocarbon reservoirs [6,7,8,9]

Summary

Introduction

The need for increasing accuracy and effective predictive models is an important challenge faced by the oil industry, which seeks to understand the distribution of permoporous spaces in hydrocarbon reservoirs. In this context, multidisciplinary/multiscale studies on carbonate rocks, especially those formed by concentrations of fossils (coquina), have been developed, aiming for a better understanding on pre-salt reservoirs in the Brazilian Atlantic Border Basins, namely, in the Santos and Campos Basins [1,2]. The approach applied in this work for fossil assemblages and other nonbioclastic elements refers to a classification system for coquina reservoirs based on bioestratinomic and fossil-diagenetic processes, and on the resulting products [13]

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