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Title: Geology and major oil plays, Coastal Margin basins, Brazil

Abstract

Six major tectonic-depositional sequences, reflecting rift and passive margin evolution, variously characterize the filling of Brazilian coastal margin basins: (1) Late Jurassic prerift, (2) Early Cretaceous tectonic rift, (3) Early Cretaceous quiescent stage (evaporitic or calcilutitic), (4) middle Cretaceous platform/deltaic progradational and deep marine retrogradation, and (6) Tertiary main passive margin progradation. Habitat of oil discovered to date meets two regional geologic conditions: (1) in tectonic rifts known to have basin core of starved, lacustrine shales, and (2) in basins which developed a quiescent phase during the transition from tectonic rift to passive margin. Two major plays characterize the central core rifts, including (I) underlying prerift sediments in fault contact with the central core, and (II) sublacustrine fans overlying the central core. These plays, typified in the Reconcavo basin, constitute about half the recoverable oil found to date. Exploration implications of the established plays are: (1) source is from tectonic or quiescent stage fill (Aptian or older); (2) structural integrity of the quiescent stage seals is critical to oil migration; and (3) tectonic rifts are productive when a core of deep lacustrine shales was developed.

Authors:
;
Publication Date:
Research Org.:
PETROBRAS, Rio de Janeiro, Brazil
OSTI Identifier:
6186220
Report Number(s):
CONF-8405216-
Journal ID: CODEN: AAPGB
Resource Type:
Conference
Resource Relation:
Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States); Journal Volume: 68:4; Conference: AAPG annual convention, San Antonio, TX, USA, 20 May 1984
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; BRAZIL; CONTINENTAL MARGIN; SEDIMENTARY BASINS; PETROLEUM DEPOSITS; EXPLORATION; PETROLEUM GEOLOGY; CARBONATE ROCKS; CRETACEOUS PERIOD; DEPOSITION; JURASSIC PERIOD; SOURCE ROCKS; TECTONICS; TERTIARY PERIOD; CENOZOIC ERA; DEVELOPING COUNTRIES; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; GEOLOGY; LATIN AMERICA; MESOZOIC ERA; MINERAL RESOURCES; RESOURCES; ROCKS; SEDIMENTARY ROCKS; SOUTH AMERICA 020200* -- Petroleum-- Reserves, Geology, & Exploration

Citation Formats

Mosmann, R., and Fisher, W.L.. Geology and major oil plays, Coastal Margin basins, Brazil. United States: N. p., 1984. Web.
Mosmann, R., & Fisher, W.L.. Geology and major oil plays, Coastal Margin basins, Brazil. United States.
Mosmann, R., and Fisher, W.L.. 1984. "Geology and major oil plays, Coastal Margin basins, Brazil". United States. doi:.
@article{osti_6186220,
title = {Geology and major oil plays, Coastal Margin basins, Brazil},
author = {Mosmann, R. and Fisher, W.L.},
abstractNote = {Six major tectonic-depositional sequences, reflecting rift and passive margin evolution, variously characterize the filling of Brazilian coastal margin basins: (1) Late Jurassic prerift, (2) Early Cretaceous tectonic rift, (3) Early Cretaceous quiescent stage (evaporitic or calcilutitic), (4) middle Cretaceous platform/deltaic progradational and deep marine retrogradation, and (6) Tertiary main passive margin progradation. Habitat of oil discovered to date meets two regional geologic conditions: (1) in tectonic rifts known to have basin core of starved, lacustrine shales, and (2) in basins which developed a quiescent phase during the transition from tectonic rift to passive margin. Two major plays characterize the central core rifts, including (I) underlying prerift sediments in fault contact with the central core, and (II) sublacustrine fans overlying the central core. These plays, typified in the Reconcavo basin, constitute about half the recoverable oil found to date. Exploration implications of the established plays are: (1) source is from tectonic or quiescent stage fill (Aptian or older); (2) structural integrity of the quiescent stage seals is critical to oil migration; and (3) tectonic rifts are productive when a core of deep lacustrine shales was developed.},
doi = {},
journal = {Am. Assoc. Pet. Geol., Bull.; (United States)},
number = ,
volume = 68:4,
place = {United States},
year = 1984,
month = 4
}

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  • Six major tectonic-depositional sequences, reflecting rift and passive margin evolution, variously characterize the filling of Brazilian coastal margin basins: (1) Late Jurassic prerift, (2) Early Cretaceous tectonic rift, (3) Early Cretaceous quiescent stage (evaporitic or calcilutitic), (4) middle Cretaceous platform/deltaic progradational and deep marine retrogradation, and (6) Tertiary main passive margin progradation. Habitat of oil discovered to date meets two regional geologic conditions: (1) in tectonic rifts known to have basin core of starved, lacustrine shales, and (2) in basins which developed a quiescent phase during the transition from tectonic rift to passive margin. Two major plays characterize the centralmore » core rifts, including (I) underlying prerift sediments in fault contact with the central core, and (II) sublacustrine fans overlying the central core. These plays, typified in the Reconcavo basin, constitute about half the recoverable oil found to date. Exploration implications of the established plays are: (1) source is from tectonic or quiescent stage fill (Aptian or older); (2) structural integrity of the quiescent stage seals is critical to oil migration; and (3) tectonic rifts are productive when a core of deep lacustrine shales was developed.« less
  • Sergipe-Alagoas, Jequitinhonha, Espirito Santo, and Campos basins are located along the east Brazilian continental margin in South America. These basins present 3 major Mesozoic and Cenozoic sedimentary sequences ranging from continental to open-marine environments. Two structural styles produced 3 major exploratory plays, both structural and stratigraphic. Structures are related, first, to an early tectonic framework of the basins caused by extensional forces, when an irregular hinge line was developed, and later, to gravity sliding and sedimentary loading when an entire set of structures that depict complex structural and sedimentary patterns from the border of the basins toward the hinge line,more » and from the hinge line down to the basins. The tectonic-structural model defines trends for hydrocarbon exploration. More than 80 oil and gas fields have been discovered in both onshore and offshore portions of the east Brazilian margin basins. Oil-field data plus a large amount of subsurface and seismic reflecting data support the proposed model used to establish the global exploratory strategy for the east Brazilian margin basins. Such a model can also be useful for homotaxial analogy in areas where similar geologic conditions occurred; however, it is necessary to keep in mind that each basin has unique features.« less
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  • Oil and gas have been produced from the Knox Group in the Appalachian basin since the early 1990s. However, only since the 1960s have significant volumes of hydrocarbons been produced. Porosity development along the Knox unconformity is the dominant geologic control for hydrocarbon migration and entrapment. Other important controls include stratigraphy, diagenesis, paleokarst, structure, and fractures. Cumulative production is ultimately, controlled by the reservoir conditions characteristic to each play. The two most significant Knox plays in terms of total cumulative gas production are (1) the Lower Ordovician-Upper Cambrian eroded shelf sandstones known as the Rose Run sandstone in Kentucky, Ohio,more » and Pennsylvania, and the Theresa sandstone in New York, and (2) the Lower Ordovician-Upper Cambrian paleokarstic carbonates known as the Beekmantown dolomite in Kentucky, Ohio, and Tennessee, and the Copper Ridge (Trempealeau) dolomite in Ohio. Minor volumes of gas have been produced from fracture and paleokarstic carbonate plays in the Know dolomite of Kentucky, Tennessee, and Virginia, and from localized sandstones of the Copper Ridge (Trempealeau) in Ohio. Some individual wells in Ohio have produced more than 1 billion ft[sup 3] of gas from the Beekmantown, Rose Run, or Copper Ridge (Trempealeau). Cumulative gas production from all the Knox plays in the Appalachian basin has been in excess of 60 billion ft[sup 3] of gas. The Knox Group plays are currently the most active exploration targets in the basin.« less