Re-sedimented deposits in the rift section of the Campos Basin

Goldberg, Karin; Küchle, Juliano; Scherer, Claiton Marlon dos Santos; Alvarenga, Renata dos Santos; Ene, Patrycia Leipnitz; Armelenti, Garibaldi; Ros, Luiz Fernando De

doi:10.1016/j.marpetgeo.2016.11.022

Cited by 40 publications

(46 citation statements)

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“…and of exposure surfaces in massive bioclastic reservoirs about 100 meters thick, suggests that they were accumulated in relatively deep lacustrine environments. The extensive resedimentation of the bioclastic deposits by gravitational mass movements was probably triggered by tectonism, as also observed in the central area of the basin (Goldberg et al 2017). These factors allowed the accumulation of thick bioclastic deposits, which were probably remobilized from shoreface and related shallow-water environments.…”

Section: Implications For Exploration Of Lacustrine Carbonatesmentioning

confidence: 70%

“…This paragenetic evolution of the bioclastic rudstones and grainstones (Fig. 12) differs from that of equivalent rocks from the central and southern parts of the basin, where there is a predominance of aragonite neomorphism in relation to dissolution (Bertani and Carozzi 1985b;Altenhofen 2013;Muniz 2014;Goldberg et al 2017).…”

Section: Porosity Permeability and Mercury Injectionmentioning

confidence: 83%

“…Carvalho et al (2000) recognized seven main depositional environments based on facies associations, including bioclastic beaches, bioclastic sandy beaches and marginal lacustrine settings, bioclastic sheet and bar fringes, consisting of shell debris deposited by storm events, bioaccumulation banks, and deep lacustrine settings. Recently, Goldberg et al (2017) interpreted, based on the integration of quantitative petrography, sedimentology, and seismic stratigraphy, that the bioclastic rudstones correspond mostly to gravitational deposits, resedimented from structural highs to deeper lacustrine settings, throughout the rift section of the basin.…”

Section: Geological Settingmentioning

confidence: 99%

“…Experimental studies show that this evolution depends on a number of environmental factors, including pH, salinity, temperature, and ionic content (Jones 1986;Tosca and Masterson 2014). The alkaline conditions needed for stevensite precipitation (ph 10) were recurrent during the rift evolution, as stevensite arenites occur in different stages and areas of the Campos rift Carozzi 1985a, 1985b;Armelenti et al 2016;Goldberg et al 2017). These conditions were very different from the fresh-water environments colonized by bivalves and gastropods.…”

Section: Origin and Diagenesis Of Stevensitementioning

confidence: 99%

“…These conditions were very different from the fresh-water environments colonized by bivalves and gastropods. The common mixture of stevensite ooids and peloids with bivalve bioclasts in the Campos Basin rift section indicates their extensive gravitational resedimentation in deeper lacustrine environments throughout the evolution of the rift (Goldberg et al 2017). Pozo and Casas (1999) suggested that gel coagulation would result in granular clay particles, which could explain the common peloidal habit of stevensite.…”

Section: Origin and Diagenesis Of Stevensitementioning

confidence: 99%

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Influence of Diagenesis On the Quality of Lower Cretaceous Pre-salt Lacustrine Carbonate Reservoirs from Northern Campos Basin, Offshore Brazil

Herlinger

Zambonato

Ros

2017

Journal of Sedimentary Research

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143

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The genesis and evolution of lacustrine pre-salt carbonate reservoirs, which contain giant hydrocarbon accumulations along the South Atlantic margins, has attracted major research interest. The huge extension and volume, and unusual textural and compositional features, are key elements for understanding the tectonic, structural, stratigraphic, and sedimentological generation and early evolution of the region, as well as potentially of other lacustrine carbonate systems. A systematic petrographic and petrophysical study has been performed on the Lower Cretaceous lacustrine carbonate reservoirs from northern Campos Basin, Offshore Brazil, in order to unravel the main controls on the origin and evolution of pore systems. The main lithologic types recognized in the rift section are bivalve-gastropod grainstones and rudstones, arenites constituted by ooids of syngenetic magnesian clay minerals (mostly stevensite), and dolostones, while stevensitic claystones with calcite spherulites, fascicular calcite crusts, intraclastic rudstones and grainstones, and dolostones are the main lithologic types in the sag section. The eogenetic evolution of bioclastic reservoirs was controlled by the balance between dissolution and neomorphism of the aragonitic bivalve and gastropod bioclasts, favoring either the generation of poorly connected moldic porosity or the preservation of well-connected interparticle porosity. The stevensitic arenites were strongly affected by meteoric dissolution and replacement by dolomite and silica, related to regional uplift and erosion after the rift phase, which generated highly heterogeneous pore systems with moldic, intercrystalline, vugular, and microcrystalline pores. Stevensitic claystones that are replaced by calcite spherulites and dolomite normally show low porosity, but locally constitute reservoirs, where secondary porosity was generated by stevensite dissolution. The precipitation of crystal shrubs of fascicular-optic calcite in coalescent crusts generated growth-framework primary porosity, which was reduced mostly by dolomite cementation, or enlarged by dissolution, enhancing their permeability. Non-coalescent calcite crusts contain abundant syngenetic magnesian clay minerals. Their porosity is related to dissolution of these clays, which generated poor permeability. Intraclastic grainstones and rudstones are compacted and cemented, or rich in clay matrix (''hybrid packstones''). Where they display preserved interparticle primary porosity or matrix dissolution, they may have good porosity and permeability. The heterogeneous dolomitization of both the rift and the sag deposits either destroyed their primary or early diagenetic porosity, or generated high porosity and permeability values in the dolostones. Relationships between replacement and compaction indicate that most of the diagenetic processes occurred during eodiagenesis, controlled mostly by the instability of the aragonite in the bioclastic reservoirs and of the stevensite in the claystones, ooidal arenites, and fascicular calcite c...

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Section: Implications For Exploration Of Lacustrine Carbonatesmentioning

confidence: 70%

Section: Porosity Permeability and Mercury Injectionmentioning

confidence: 83%

Section: Geological Settingmentioning

confidence: 99%