Seismic Morphology of Pleistocene Turbidites from Southeast Nigeria: Applications to Ancient Deposits Modeling EP M 4 7 TOC Help SS Search C Author Br

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1 Seismic orpholog of Pleistocene Turbidites from Southeast Nigeria: Applications to Ancient Deposits odeling TO Help Search Author, Eric Total Research enter Structural & Sedimentologic Department Av. Larribau 698 Pau, France Start Print 8.5 x Abstract. To perform an inventor of the different turbidite sstems in order to understand the stratigraphic link and the deposit process,. To provide sub-surface analogues in terms of morpholog, size, and seismic response. These analogs are one of the tools currentl used for exploration, appraisal, and also modeling. This approach is complementar with outcr analogs.. To evaluate the seismic artifacts generated b the shallow series that could affect the visibilit of the seismic in the reservoir objectives. The shallow part of seismic deep offshore of Nigeria (sea bottom to Pliocene) is generall screened to appraise shallow hazards which could appear during drilling or on a geotechnical point of view. Also, thanks to the ver good qualit of the D high resolution seismic, these time sections are also studied with a morphological objective and reveal geological treasures as well on the level of turbidite architecture features, as on the deposit-remobilization processes. This quick look stud was performed on an area located on the eastern part of the Niger delta Eastern Lobe (Fig. ). The objectives were multiple: Seismic Imaging of Depositional and eomorphic Sstems

2 pholog and evolution (low sinuosit channels, meandering lateral stacked channels, straig channel, canon, lobe, avulsion, etc.). A first interpretation in terms of chronolog of the deposits and their relations is suggested (Fig. ). A particular focus will also be done on the internal deposit architecture of some turbidite sstems in terms of seismic features, chronolog, sedimentar filling, etc. The Plio-Pleistocene was investigated but this presentation deals with the Pleistocene between the sea bottom (blue lig) and the A marker (lig purple) which is considered as the base of the Pleistocene (Figs.,, and ). Four iso-prortionals laers have been calculated between the sea bottom and the A marker (Fig. 5). This quick look methodolog provides us a good overview of the distribution of the different turbidite items. These maps were generated both with near and far cube for morphological comprehension and also with a coherenc cube in order to evidence some structural aspects. The first map (coherenc) (Fig. 6), corresponding to the sea-bottom st laer ( 0 ms to 0ms), shows a widespread of several turbidite features such as low sinuous fairwas () high meandering fairwas (), canon like fairwa (), lobe () or avulsion sheet (5). These features are associated with numerous pock marks located on the fairwa margins and mud volcano (6). The following laers (laers, and ) show the diversit of the architectural elements in term of mor- ethodolog The example below illustrates the architecture of a lobe deposited in several different phases (compensation and pounded effect), this deposit in strongl driven b structural uplift (Figs. 8, 9, and 0). This lobe is, eventuall, eroded b a plugged channel. These results have been used to provide sub-surface analogues in terms of morpholog, size, and seismic response. These results are currentl integrated in the ancient turbidite evaluation. This approach is complementar with outcr analogs. An evaluation of the seismic artifacts and dimming which are generated b the shallow series was also done. Acknowledgements The authors would express their acknowledgement to NOO, NNP, PETROBRAS, SAPETRO, and TOTAL for their authorization to present this communication.

3 Figure. Location of the stud.

4 Figure. Sea bed coherenc map and time depth. Inline and ross line location.

5 Figure. Inline showing a part of the Plio-Pleistocene interval and the interval of investigation. 5

6 Figure. ross line showing a part of the Plio-Pleistocene interval and the interval of investigation. 6

7 Figure 5. Inline 600 focusing on iso-prortionals (slig green lines).

8 Figure 6. oherenc at sea bottom st laer. 8

9 Figure. oherenc and near map at Laers,,. 9

10 Figure 8. Sections crossing the pounded lobe. 0

11 Figure 9. Deep random line illustrating the pounded effect.

12 Figure 0. Pounded lobe D view.