Submarine fan morphology and lithology distribution: a predictable function of sediment delivery, gross shelf-to-basin relief, slope gradient and basin topography

Abstract

Overthe last decade comprehensiveexploration for turbiditeplays hasbeenrewarded byasignificant numberofhydrocarbon discoveries. However,the industry isstill critically challenged withrespecttoappropriate andrefined prediction ofsand/shaled istributions withint hesed epositionals ystems. Alongwithastronga nd sustained commercialinterest intheseplays,extensivesubsurface datasets,includinganewgeneration ofcoreandwell/log-calibrated seismic faciessuites,havebecomeavailable.Based on thisv aluablei nformation,systematic 2Da nd3Dseismic sequence stratigraphicalanalysisw ith particularfocus on seismic faciesandseismic geomorphologywasperformed infivedifferent basins alongNorth andSouthAtlantic margins. Each subsurface examplewascharacterized withreference to its relativesequence stratigraphic orderw ithinah ierarchy. Evolvingg eologicalp arameters like shelfa ccommodation,shelf-break position,slopegradient,slopeandbasinbathymetry/topographyandthird-, fourth-andoccasionally fifth-order stackingpatterns wereassessed withinsecond-ordercyclesineach case.Based on theseobservations,recognition criteria for subsurface lithologyp rediction wered erived.Conceptualknowledgef rom outcrop analysisw asan essentialandintegralpart ofthe interpretation process throughout the study.The subsurface recognition criteria, highlighted inthisstudy,emphasizesimilarity andvariability betweentwo end-memberbasins tyles:h igh shelf-to-basinr elief/sediment under-filled basins wheresand-pronenearshore systems don ot prograde overdeep-waterfans ystems inasecond-ordercyclec ontext; low shelf-to-basin relief/sediment over-filled basins wheresand-pronenearshoresystems doprograde overdeep-waterfansystems inasecond-ordercyclecontext.The most strikingc ontrast withrespectt odeep-waterr eservoirs andstoned istribution int he two basin categoriesrelatestothe fourth-andfifth-orderstackingpatterns offanbuilding-block cycleswithinsecond-and third-ordercycles,which tendto show low progradation/aggradation ratioint he high relief basins andh igh progradation/aggradation ratioint he low relief basins. Givenanu nderstandingofg eologicalcontext,these seismically identifiablepatterns provide morea ccurateprediction ofsanda ndshaled istribution withindeepwaterclastic systems.

Triassic seismic sequence stratigraphy and paleogeography of the western Barents Sea area

“…8A). Both on the Finnmark Platform and in the Hammerfest Basin, seismic clinothems are shown to prograde mainly from the Fennoscandian Shield during the earliest Triassic (Berglund et al, 1986;Bullimore et al, 2004;Hadler-Jacobsen et al, 2005;Skjold et al, 1998;.…”

Depositional processes across the Sinú Accretionary Prism, offshore Colombia

“…3). Slope profiles and basin filling histories are described using the terminology of Kneller (2003) and McCaffrey and Kneller (2004), while onlap styles, basin topography and accommodation space trends are described using the terminology of Smith (2004), Hadler-Jacobsen et al (2005 and Gardiner (2006).…”

“…The bathymetric configuration of many turbidite basins allows for only partial confinement of sediments, leading to complex spatial and temporal variations in both sediment facies and architecture within and across connected basins (Felletti, 2002;Hooper et al, 2002;Smith, 2004;Adeogba et al, 2005;Hadler-Jacobsen et al, 2005;Fugelli and Olsen, 2007;Jackson et al, 2008). Inferring the length scales of bathymetric control on turbidite deposits from spatially-limited data (e.g., outcrops or well data) is a key challenge to understanding the upstream or downstream transitions within the larger turbidite system to which these belong (Kneller, 1995(Kneller, , 2003McCaffrey and Kneller, 2004).…”

Submarine slope systems: processes and products

“…It appears, therefore, that deep-water system architecture at the scales of tens to a few hundred metres vertically by tens of kilometres laterally by 1-2 Ma in duration is not strongly controlled by large-scale variations in basin margin/sediment delivery system (Hadler-Jacobsen et al 2005). However, the delivery system (delta type) and shelf dimensions (width and gradient) are important controls on the sediment grain-size range and volume that reaches the shelf edge, and these input parameters have an important control on the sandbody architecture (sizes of levees, depth of erosion) and gravity flow processes.…”