Sequence Stratigraphic and fault-seal interpretations of reservoir in ' Ikeani' field, coastal swamp depobelt, Niger Delta Nigeria.
Date
2023-09
Authors
Journal Title
Journal ISSN
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Publisher
Federal University of Technology, Owerri.
Abstract
The aim of this work is to show the spartial distribution of the reservoir architectural elements in “Ikeani” Field, Coastal Swamp depobelt using data from well logs, checkshot,
biostratigraphy and 3D seismic in the evaluation of sequence stratigraphy, structural interpretation, seismic stratigraphy and amplitude extraction. The results of the sequence
stratigraphy delineates the reservoir geometries, stacking patterns, sequences and parasequences. These were directly interpreted sequel to relative sea level fluctuations and
sediments infills. It is observed that the reservoir qualities varies by virtue of the sequences (Highstand Systems Tract, Transgressive Systems Tract and Lowstand Systems Tract). The
HSTs as seen in this study have clean and better developed sand reservoirs. They are generally aggradational to progradational. The TST‟s are dirty towards the top and are mostly
retrogradational channels terminating up dip at the Maximum Flooding Surfaces (MFS). These MFS‟s considering their good thickness are likely good top seals to the TST reservoirs.
The LSTs are mainly progradational with intercalations of sand and shales typical of prograding wedge deposits, slope deposit and basin floor fan deposits. Fault truncations as
interpreted in this research, caused different reservoir closures. However, some other faults as seen in this study has penetrated some stacking geometries of reservoirs resulting to faulted out (missing section typical of C7000 Reservoir) and fault cut (short section typical of C6000) depicting non-testing of hydrocarbon in some wells such as C7000_reservior which could not be penetrated by Ikeani Well 7. Also, hydrocarbon accumulations as delimited at reservoir intervals using both well logs and seismic are complemented with the associated depo environment as interpreted in this study. However, non-faulted or four-way dip closure of a reservoir is also seen in this study. This is typical of C13000. The study adopted seismic stratigraphy to delineate the reflection configurations and patterns such as the divergent and sub-parallel seismic configurations connoting different/fluctuations of depositional environment. These were then complemented with Root Mean Square Amplitude extraction to display the diverse intermingled barrier channel truncated reservoir deposits. The sealing capacity of the reservoir is demonstrated within the fault surface utilizing the Shale Gouge Ratio (SGR) as the sealing parameter – attributing its rock components as stratigraphic juxtapositions, catalasis and influential across fault pressure as the capillary pressure. This disclosed that faults forming closures at studied reservoir levels had over 60% SGR and as such caused good sealing in C6000 reservoir by impeding further oil migration as well as being supported and capped with over 70% Volume of Shale as the top seal rock.
Description
Master's thesis in sedimentary/petroleum geology. It contains diagrams, maps and tables
Keywords
Sequence stratigraphy, Niger Delta, fault-seal interpretations, reservoir, ikeani field, coastal swamp depobelt, Department of geology
Citation
Edema, S. A. (2023). Sequence stratigraphic and fault- seal interpretations of reservoir in ' Ikeani' field coastal swamp depobelt, Niger Delta Nigeria. { Unpublished Masters Thesis }, Federal University Of Technology, Owerri.