--> Paleozoic Basins of Brazil: Challenges and Keys to Unlocking the Hydrocarbon Potential, Belopolsky, Andrei; Moore, Julian; Krassay, Andrew; Pryer, Lynn, #90100 (2009)

Datapages, Inc.Print this page

Paleozoic Basins of Brazil: Challenges and Keys to Unlocking the Hydrocarbon Potential

Belopolsky, Andrei1
 
Moore, Julian1
 Krassay, Andrew2
 Pryer, Lynn2

1BP Exploration, Sunbury on Thames, United Kingdom.
2
FrogTech,
Canberra, ACT, Australia.

Several large Paleozoic basins are located in the northern part of South America and share common tectonic history and similar petroleum systems. These basins are under-explored due to their remoteness, difficult terrain, and poor seismic imaging caused by intrusives. Solimões, Amazonas, Parnaiba, Parana and Parecis basins were initiated in the Precambrian in response to rifting between Gondwana and Laurentia. Subsequent episodes of uplift in the Cambrian and early Ordovician were followed in the late Ordovician-Silurian by another phase of rifting related to the opening of the Rheic Ocean. The late Ordovician glaciation affected Amazonas, Parnaiba and Parana basins. The subsequent Silurian flooding events deposited marine shales of variable source rock quality.

During Devonian sag phase glaciation resulted in deposition of proven reservoirs in the Northern basins. Upper Devonian black marine shales have some of the better source rock qualities. The Hercynian event in the Carboniferous caused by the collision with Laurentia resulted in substantial uplift and erosion.

During the Permian subsidence phase restricted carbonates, evaporates and marine clastics were deposited.
Parana basin also contains Permian organic-rich marine Irati shale. The overlying Mesozoic and Tertiary deposits are largely thin and non-marine. Vast amounts of volcanics were intruded in the Triassic (Penatacua) and in the Jurassic related to the opening of the South Atlantic. Cretaceous compressional events lead to the subtle inversion in the basins.

During the Paleozoic South America and
Africa were part of the same continental mass and have comparable stratigraphy and share similar petroleum systems elements. For example, organic-rich marine shales of Silurian age extend from the Solimões basin to the Murzuk basin in Libya. However, differences in basin locations with respect to oceanographic setting may have affected the presence and quality of source rock facies. Similarly, key sequence bounding unconformities, such as the Hercynian event, can be traced between South America and North Africa.

The challenges in the exploring for hydrocarbons in these basins lay in obtaining good seismic imaging and understanding the potential and maturation of the source rocks, burial histories and hydrocarbon migration relative to the trap formation timing. Several oil and gas fields and significant hydrocarbon shows indicate substantial potential for these large poorly-explored basins.


AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil