High-resolution sequence biostratigraphy of a lowstand prograding deltaic wedge: Oso Field (late Miocene), Nigeria

Abstract

High-resolution biostratigraphic analyses provide calibration of both depositional systems and specific depositional environments. Such studies facilitate prediction of reservoir geometry and the lateral continuity of both reservoir sandstones and sealing mudstones. Data from the offshore Nigeria Oso Field are presented as a case study of one late Miocene deltaic depositional system. Within the Oso Field, marine mudstones are recognized as effective top seals across the entire field in contrast to marginal marine to non-marine mudstones which have more restricted distribution and act as intrafield baffles. Three sequence stratigraphic models have been considered: (1) the first is based on biostratigraphic data integrated with core sedimentology; (2) a second model constructed using core sedimentology; and (3) a third based on interpreted regional seismic reflection profiles and well-log data. Integration of all data shows that the lower Oso Field producing interval is interpreted as a lowstand prograding wedge, and the upper interval as a prograding distal transgressive or alternatively distal highstand system tract.

Three-dimensional seismic geomorphology of a deep-water slope-channel system: The Sequoia field, offshore west Nile Delta, Egypt

“…Excellent seismically based examples have been documented from offshore Angola (Mayall and Stewart, 2000;Prather et al, 2000;Sikkema and Wojcik, 2000;Kolla et al, 2001;Mayall and O'Bryne, 2002;Navarre et al, 2002;Abreu et al, 2003;Prather 2003), offshore Nigeria (Armentrout et al, 1999;Pirmez et al, 2000;Chapin et al, 2002;Deptuck et al, 2003;Fonnessu, 2003;Prather, 2003), the west of Shetlands (Lamers and Carmichel, 1999;Leonard et al, 2000), the United Kingdom North Sea (Jeanette et al, 2000(Jeanette et al, , 2003aLeonard et al, 2000), Indonesia (Demyttenaere et al, 2000;Posamentier et al, 2000;Guritno et al, 2003;Saller et al, 2003;Saller et al, 2004;Mayall et al, 2006), the Gulf of Mexico (Prather et al, 1998;Varnai, 1998;Beaubouef et al, 1999;Friedmann and Beaubouef, 1999;O'Byrne et al, 1999;Beaubouef and Friedmann, 2000;Fugitt et al, 2000;Jeanette et al, 2003b;Posamentier and Kolla, 2003), offshore Trinidad (Brami et al, 2000), and the Brazilian Campos Basin (Bruhn, 1998(Bruhn, , 2001Ragagnin and Moraes, 2008).…”

High-resolution last deglaciation record from the Congo fan reveals significance of mangrove pollen and biomarkers as indicators of shelf transgression

“…Whilst some studies identify a general association between high mangrove pollen and the maximum flooding surface associated with the humid (interglacial) component of Quaternary climate cycles (e.g., Fredoux, 1994;Pickett et al, 1997;Poumot, 1989;van der Zwan and Brugman, 1999), others associate mangrove spikes specifically with transgressive systems tracts (e.g., Armentrout et al, 1999;Hoorn, 1994). Ventris (in Armentrout et al, 1999) goes further and identifies high abundance occurrences during the late lowstand-early transgressive phase of slow relative sea-level rise and also during the highstand phase of relative sea-level. The former occurs when much of the coastal plain is aggrading and supporting a wide mangrove belt, and the latter is associated with progradation.…”

Palynological Characteristic of Dark Gray Clays in the Ivorian Onshore Basin at Southern Bingerville

“…Armentrout et al [21] attribute this same pollen to freshwater swamp forests. Tree ferns such as cyathidites minor (cyatheacea) and Polypodiaceoisporites regularis (Pteridaceae) inhabit thick tropical forests [18,19].…”