Pressure prediction in the Bullwinkle Basin through petrophysics and flow modeling (Green Canyon 65, Gulf of Mexico)

Flemings, Peter B.; Lupa, J. A.

doi:10.1016/j.marpetgeo.2004.09.005

Cited by 20 publications

(11 citation statements)

References 15 publications

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“…We suggest the overpressure was driven by this rapid sedimentation. The high pore pressures in the Brazos‐Trinity Basin IV region fit into a range of results that have recently documented overpressures in the shallow subseafloor [ Dugan and Germaine , 2008; Flemings and Lupa , 2004; Flemings et al , 2008; Orange et al , 2003; R. M. Ostermeier et al, Dealing with shallow water flow in the deepwater Gulf of Mexico, paper presented at Offshore Technology Conference 2000, Society of Petroleum Engineers, Houston, Texas, 2000].…”

Section: Discussionsupporting

confidence: 65%

“…For example, Hart et al [1995] assumed the known section is hydrostatically pressured. Others have used direct observations of pressure to constrain the vertical effective stress at a known location [ Flemings and Lupa , 2004]. Our approach is to use laboratory experiments and a direct pore pressure measurement from Site U1319 to infer the vertical effective stress and pore pressure at Site U1319.…”

Section: Pressure Characterizationmentioning

confidence: 99%

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Overpressure and consolidation near the seafloor of Brazos‐Trinity Basin IV, northwest deepwater Gulf of Mexico

et al. 2009

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[1] Pore water overpressures (u*) within mudstones beneath Brazos-Trinity Basin IV (deepwater Gulf of Mexico, offshore Texas) are greater than 70% of the hydrostatic vertical effective stress (s 0 vh ) [l* = 0.7 = (u*/s 0 vh )]. These results are compatible with recent observations that suggest sedimentation rates in this region are rapid (6 mm/a). We compare the petrophysical properties and pore pressures within a 127-m-thick package of mudstone penetrated at two locations: Integrated Ocean Drilling Program (IODP) sites U1319 and U1320. Site U1319 is at the margin of Brazos-Trinity Basin IV, whereas Site U1320 lies at its center, beneath 180 m of turbidite fill. Experimentally derived preconsolidation stresses and an in situ pore pressure measurement record overpressure at Site U1319 and Site U1320 (l* $ 0.2 to 0.8 and l* $ 0.8, respectively). We use these data to define an average vertical effective stress gradient. Assuming that void ratio (e) is proportional to the log of vertical effective stress (s 0 v ), we predict pore pressures (u) throughout the mudstone at both sites using bulk density data. Overpressures are greater at Site U1320 due to rapid deposition of the overlying turbidites. However, a large fraction of the overpressure induced by the turbidite load applied at Site U1320 has dissipated by drainage into the overlying basin fill. High overpressures near the seafloor drive shallow fluid flow, reduce slope stability, and may explain large submarine landslides.

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Section: Discussionsupporting

confidence: 65%

Section: Pressure Characterizationmentioning

confidence: 99%

Overpressure and consolidation near the seafloor of Brazos‐Trinity Basin IV, northwest deepwater Gulf of Mexico

et al. 2009

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“…Deep flow systems in the region are commonly characterized using seismic, logging, and production data (Harrison and Summa, 1991;Flemings and Lupa, 2004;Seldon and Flemings, 2005). Shallow sedimentary systems have been evaluated using seismic data Wood et al, 2008), shallow coring activities (Flemings et al, 2006), and seafloor observations .…”

Section: Overviewmentioning

confidence: 99%

Physical properties of sediments from Keathley Canyon and Atwater Valley, JIP Gulf of Mexico gas hydrate drilling program

Winters

Dugan

Collett

2008

Marine and Petroleum Geology

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a b s t r a c tPhysical property measurements and consolidation behavior are different between sediments from Atwater Valley and Keathley Canyon in the northern Gulf of Mexico. Void ratio and bulk density of Atwater Valley sediment from a seafloor mound (holes ATM1 and ATM2) show little effective stress (or depth) dependence to 27 meters below seafloor (mbsf), perhaps owing to fluidized transport through the mound itself with subsequent settling onto the seafloor or mound flanks. Off-mound sediments (hole AT13-2) have bulk physical properties that are similar to mound sediments above 27 mbsf, but void ratio and porosity decrease below that depth. Properties of shallow (<50 mbsf) Keathley Canyon sediments (KC151-3) change with increasing effective stress (or depth) compared to Atwater Valley, but vary little below that depth. Organic carbon is present in concentrations between typical near-shore and deep-sea sediments. Organic carbon-to-nitrogen ratios suggest that the organic matter contained in Atwater Valley off-mound and mound sites came from somewhat different sources. The difference in organic carbon-to-nitrogen ratios between Atwater Valley and Keathley Canyon is more pronounced. At Keathley Canyon a more terrigenous source of the organic matter is indicated. Grain sizes are typically silty clay or clay within the two basins reflecting similar transport energy. However, the range in most shallow sediment properties is significantly different between the two basins. Bulk density profiles agree with logging results in Atwater Valley and Keathley Canyon. Agreement between lab-derived and loggingderived properties supports using logging data to constrain bulk physical properties where cores were not collected.Published by Elsevier Ltd.

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“…1). Flemings and Lupa (2004) derived sedimentation rates for the Bullwinkle Basin in the Gulf of Mexico using a biostratigraphic correlation by Styzen (1996) and calculating the thickness of sediments at deposition assuming a constant depositional porosity of 0.6.…”

Section: Geological Contextmentioning

confidence: 99%

Stress and pore pressure histories in complex tectonic settings predicted with coupled geomechanical-fluid flow models

Obradors-Prats

Rouainia

Aplin

et al. 2016

Marine and Petroleum Geology

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. (2016) 'Stress and pore pressure histories in complex tectonic settings predicted with coupled geomechanical-uid ow models.', Marine and petroleum geology., 76 . pp. 464-477. Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractMost of the methods currently used for pore pressure prediction in sedimentary basins assume one-dimensional compaction based on relationships between vertical effective stress and porosity. These methods may be inaccurate in complex tectonic regimes where stress tensors are variable. Modelling approaches for compaction adopted within the geotechnical field account for both the full three-dimensional stress tensor and the stress history. In this paper a coupled geomechanical-fluid flow model is used, along with an advanced version of the Cam-Clay constitutive model, to investigate stress, pore pressure and porosity in a Gulf of Mexico style mini-basin bounded by salt subjected to lateral deformation. The modelled structure consists of two depocentres separated by a salt diapir. 20% of horizontal shortening synchronous to basin sedimentation is im-posed. An additional model accounting solely for the overpressure generated due to 1D disequilibrium compaction is also defined. The predicted deformation regime in the two depocentres of the mini-basin is one of tectonic lateral compression, in which the horizontal effective stress is higher than the vertical effective stress. In contrast, sediments above the central salt diapir show lateral extension and tectonic vertical compaction due to the rise of the diapir. Compared to the 1D model, the horizontal shortening in the mini-basin increases the predicted present-day overpressure by 50%, from 20 MPa to 30 MPa. The porosities predicted by the mini-basin models are used to perform 1D, porosity-based pore pressure predictions. The 1D method underestimated overpressure by up to 6 MPa at 3400 m depth (26% of the total overpressure) in the well located at the basin depocentre and up to 3 MPa at 1900 m depth (34% of the total overpressure) in the well located above the salt diapir. The results show how 2D/3D methods are required to accurately predict overpressure in regions in which tectonic stresses are important.

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Pressure prediction in the Bullwinkle Basin through petrophysics and flow modeling (Green Canyon 65, Gulf of Mexico)

Cited by 20 publications

References 15 publications

Overpressure and consolidation near the seafloor of Brazos‐Trinity Basin IV, northwest deepwater Gulf of Mexico

Overpressure and consolidation near the seafloor of Brazos‐Trinity Basin IV, northwest deepwater Gulf of Mexico

Physical properties of sediments from Keathley Canyon and Atwater Valley, JIP Gulf of Mexico gas hydrate drilling program

Stress and pore pressure histories in complex tectonic settings predicted with coupled geomechanical-fluid flow models

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