Characterizing scales of sedimentary heterogeneity in a fluvial—estuarine reservoir analog: An example from the Mulichinco Formation, Neuquén Basin, Argentina

Mariana S. Olivo, Diego A. Kietzmann, Laura J. Schencman, Daniel Minisini, Julián Espínola, Nicolás D. Waldmann

Research output: Contribution to journalArticlepeer-review

Abstract

An integrated stratigraphic, sedimentological and petrophysical analysis is presented to document the variety of sedimentary heterogeneities scales that can occur in a fluvial–estuarine reservoir analog. In this context, outcrops of the Mulichinco Formation (Neuquén Basin, Argentina) were investigated combining architectural analysis, vertical and lateral facies organization, and reservoir properties distributions in different channel-body types. Six main facies associations have been defined: gravelly–sandy to sandy braided channels, meandering channels, floodplain deposits, tidally influenced terminal channels, and subtidal to intertidal plains deposits, which we interpret the deposition in a proximal to distal fluvial and inner estuarine systems. Sequence stratigraphic analysis suggest the fluvial–estuarine succession evolved from a lower to an upper interval representative of low to high accommodation versus sediment supply ratios, respectively. Variations in accommodation and spatial changes from on-to off-axis locations within the fluvial system might performed as large-scale controls in stratigraphic and spatial variations of channel-deposits proportions and connectedness, which decreases vertically and horizontally towards the N and SE. Moreover, these trends could be overprinted by the avulsion influence. Distribution and preservation-style of fines within the channels define different intra-channel-body compartments controlled by distinct allogenic and autogenic processes. Cross-bedded sandstones represent the facies with the greatest reservoir quality, but they record the widest range in petrophysical values and textural variations, which represent unfavourable potential facies-scale reservoir compartments and barriers. Finally, variations in cement mineralogy would be the first-order control for permeability distribution and reservoir quality separation throughout the different channel units, since clay-rich cements contain the highest values of microporosity and permeability. Therefore, primary depositional processes followed by diagenesis strongly controlled the sandstone properties as reservoir. This work provides a characterization for stratigraphic-to pore-scale sedimentary heterogeneities and may contribute to the improvement of predictive models for exploration and development strategy of fluvial–inner estuarine reservoirs.

Original languageEnglish
Article number104604
JournalMarine and Petroleum Geology
Volume121
DOIs
StatePublished - Nov 2020
Externally publishedYes

Bibliographical note

Funding Information:
This research has been developed under the framework of the PICT-2016-3762 Project supported by Agencia Nacional de Promoción Científica y Tecnológica . This work has also been supported by postdoctoral fellowships awarded by CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) , Argentina; the Ministry of External Relationships of the State of Israel and the University of Haifa , Israel. CONICET and an agreement between the University of Buenos Aires, Argentina, and Shell, United States (LOU 4900023995 Project); supported fieldwork activities. The authors thank Fernando Sanchez-Ferrer ( Shell, United States ) for supporting the development of this study, for the insights on its applications to reservoirs and for stimulating intellectual discussion. M. Olivo sincerely thanks Prof. G. Hampson and H. Campos for helping with doubts about methodology and thematic, and their valuable comments. The manuscript has benefitted from constructive comments made by Jesse Pisel and Domenico Chiarella. We would like to thank Dr. N. Taha (University of Haifa), Dr. Y. Hatzor and Y. Gordin (Deichmann Rock Mechanics Laboratory, Ben-Gurion University of the Negev) for their assistance for porosity and permeability analyses.

Funding Information:
This research has been developed under the framework of the PICT-2016-3762 Project supported by Agencia Nacional de Promoci?n Cient?fica y Tecnol?gica. This work has also been supported by postdoctoral fellowships awarded by CONICET (Consejo Nacional de Investigaciones Cient?ficas y T?cnicas), Argentina; the Ministry of External Relationships of the State of Israel and the University of Haifa, Israel. CONICET and an agreement between the University of Buenos Aires, Argentina, and Shell, United States (LOU 4900023995 Project); supported fieldwork activities. The authors thank Fernando Sanchez-Ferrer (Shell, United States) for supporting the development of this study, for the insights on its applications to reservoirs and for stimulating intellectual discussion. M. Olivo sincerely thanks Prof. G. Hampson and H. Campos for helping with doubts about methodology and thematic, and their valuable comments. The manuscript has benefitted from constructive comments made by Jesse Pisel and Domenico Chiarella. We would like to thank Dr. N. Taha (University of Haifa), Dr. Y. Hatzor and Y. Gordin (Deichmann Rock Mechanics Laboratory, Ben-Gurion University of the Negev) for their assistance for porosity and permeability analyses.

Publisher Copyright:
© 2020 Elsevier Ltd

Keywords

  • Channel connectivity
  • Compartmentalization
  • Fluvial–estuarine reservoir
  • Reservoir properties
  • Sedimentary heterogeneities
  • Tight-gas

ASJC Scopus subject areas

  • Oceanography
  • Geophysics
  • Geology
  • Economic Geology
  • Stratigraphy

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