The volumetric potential assessment of the oil shales of Trememb\xe9 Formation, Taubat\xe9 Basin, Brazil

Fernanda Setta,Cleveland Jones,Marco Brito,Egberto Pereira,Sérgio Bergamaschi,Hernani Chaves,René Rodrigues

doi:10.1007/s13202-020-00846-z

Fernanda Setta, Cleveland Jones + Show 5 more

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https://doi.org/10.1007/s13202-020-00846-z

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Abstract

This assessment of the volumetric potential of the oil shales of Tremembé Formation (Oligocene, Taubaté Basin, Brazil) was based on the sedimentological study of 2457 total organic carbon and 1007 Rock–Eval pyrolysis analyses of core samples from nine survey wells drilled in the central portion of Taubaté Basin. Along a 240-m-thick package in the upper part of Tremembé Formation, thirteen chemostratigraphic units with thicknesses varying from 10 to 35 m were identified. The upper interval (unit L), 30 m thick, exhibited the highest organic content and original generation potential and was thus studied in detail. In unit L, oil yield maps were constructed, seeking to identify the most attractive areas for industrially exploiting the oil shales, and volumetric calculations employing a probabilistic Monte Carlo method were conducted to quantify the potentially recoverable oil volume. Three exploratory scenarios based on yield values (S1 + S2) were considered for calculating the oil volumes, seeking to offer different exploratory scenarios for decision making. For the scenario that considered only average yields above 100 mg HC/g rock, the recoverable oil volume is 525 million bbl (P90) to 884 million bbl (P10); for the scenario that considered only average yields above 80 mg HC/g rock, the recoverable oil volume is 1.4 billion bbl (P90) to 2.6 billion bbl (P10); and for the scenario that considered only average yields above 60 mg HC/g rock, the recoverable oil volume is 3.6 billion bbl (P90) to 5.4 billion bbl (P10).

Highlights

Brazil has an enormous potential for unconventional resources to be explored in the different sedimentary basins within its territory, and in particular, its oil shales
Among the unconventional hydrocarbon resources in Brazil, those related to the oil shales of the Tremembé Formation in Taubaté Basin, in São Paulo state (Fig. 1), have historically attracted the greatest attention regarding their economic recovery potential (e.g., Abreu 1936; Padula 1969; Dyni 2006)
To illustrate the vertical distribution of the Total organic carbon (TOC) and the Rock–Eval pyrolysis values in the upper section of the Tremembé Formation, the TMB-3-SP well (Fig. 3) was utilized as an example, since among all wells, it penetrated the thickest section of Tremembé Formation (240 m)

Summary

Introduction

Brazil has an enormous potential for unconventional resources to be explored in the different sedimentary basins within its territory, and in particular, its oil shales. Among the unconventional hydrocarbon resources in Brazil, those related to the oil shales of the Tremembé Formation in Taubaté Basin, in São Paulo state (Fig. 1), have historically attracted the greatest attention regarding their economic recovery potential (e.g., Abreu 1936; Padula 1969; Dyni 2006). These resources were industrially exploited until the mid-1900s, by the extinct Conselho Nacional de Petróleo (CNP—National Petroleum Council), through an extraction plant in Pindamonhangaba, SP, with a processing capacity of up to 10 thousand barrels per day (Milani and Araújo 2003). A volumetric assessment of hydrocarbons (in bbl), under three different exploration scenarios, was made for the chemostratigraphic subunits considered to be the most important

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