Microfabric analysis and poral characterization of microbialites: Yacoraite Formation, Maimará, Jujuy, Argentina.

VILLAFAÑE, PATRICIO; CARLOS A. CONSOLE GONELLA

Berlín

Congreso; 5th International YES Congress; 2019

Young Earth Scientists Network (YES Network)

The Yacoraite Formation (Maastrichtian - Danian) is a key unit in the north of Argentina because it is parent rock and reservoir ofhydrocarbons. One of most conspicuous facies association along Yacoraite basing are microbialitic levels that acts as reservoir.Unlike detrital limestones or crystalline dolomites, the petrophysical characteristics of the microbialites are controlled by the microfabricinstead of the granulometry or texture. This can have an impact when estimating the amount of hydrocarbons, the efficiency of recoveryand reservoir models. However, until now, the microbialites of the Yacoraite Formation do not have a characterization from ageomicrobiological point of view.Therefore, this work focused on defining the existing relationship between the microfabric and the pores in the microbialites levels of theYacoraite Formation outcropping at Maimará locality (Jujuy, Argentina). For this, a detailed study of the microfabric was carried out in orderto understand the processes that worked in the formation of the internal structure of the microbialites, and its relationship with the porosity,as influencing factor on petrophysical characteristics.Studied microbialites present a microfabric composed mainly by the intercalation of micritical laminae, where the superficial precipitation ofminerals (mineralization) is the main process of formation. The porosity exceeded 35% of the surface of the sampless, and its is practicallyof syn-sedimentary origin (fenestral). The pores in these deposits are closely related to the microfabric, so their study provides a new toolin subsurface mapping and the evaluation of petrophysical flow units.