Dynamic reservoir sand characterization of an oil field in the Niger Delta from seismic and well log data

Bonga oil field is located 120km (75mi) southeast of the Niger Delta, Nigeria. It is a subsea type development located about 3500ft water depth and has produced over 330 mmstb of hydrocarbon till date with over 16 oil producing and water injection wells. The producing formation is the Middle to Late Miocene unconsolidated turbidite sandstones with lateral and vertical homogeneities in reservoir properties. This work, analysis the petrophysical properties of the reservoir units for the purpose of modeling the effect of shale content on permeability in the reservoir. Turbidite sandstones are identified by gamma-ray log signatures as intervals with 26-50 API, while sonic, neutron, resistivity, caliper and other log data are applied to estimate volume of shale ranging between 0.972 v/v for shale intervals and 0.0549 v/v for turbidite sands, water saturation of 0.34 v/v average in most sand intervals, porosity range from 0.010 for shale intervals to 0.49 v/v for clean sands and permeability values for the send interval 11.46 to2634mD, for intervals between 7100 to 9100 ft., Data were analyzed using the Interactive Petrophysical software that splits the whole curve into sand and shale zones and estimates among other petrophysical parameters the shale contents of the prospective zones. While Seismic data revealed reservoir thickness ranging from 25ft to over 140ft well log data within the five wells have identified sands of similar thickness and estimated average permeability of700mD. Within the sand units across the five wells, cross plots of estimated porosity, volume of shale and permeability values reveal strong dependence of permeability on shale volume and a general decrease in permeability in intervals with shale volume. It is concluded that sand units with high shale contents that are from0.500 to0.900v/v will not provide good quality reservoir in the field.

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Identification of different types of paleochannels using 3D seismic and well log data: Special features by the example of oil field in western Siberia

10.1190/segam2020-3428130.1 ◽

2020 ◽

Author(s):

Marat Mazitov ◽

Alexander Kalugin ◽

Tatiana Kiryanova ◽

Oksana Kirzeleva ◽

Milana Fedorova

Keyword(s):

Western Siberia ◽

Oil Field ◽

Well Log ◽

3D Seismic ◽

Log Data ◽

Different Types

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Hydrocarbon reservoir characterization of “Otan-Ile” field, Niger Delta

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-020-01069-y ◽

2021 ◽

Vol 11 (2) ◽

pp. 601-615

Author(s):

Tokunbo Sanmi Fagbemigun ◽

Michael Ayu Ayuk ◽

Olufemi Enitan Oyanameh ◽

Opeyemi Joshua Akinrinade ◽

Joel Olayide Amosun ◽

...

Keyword(s):

Niger Delta ◽

Reservoir Characterization ◽

Water Saturation ◽

Structural Deformation ◽

Well Log ◽

Reservoir Properties ◽

Good Tool ◽

Log Data ◽

Hydrocarbon Reservoir ◽

Hydrocarbon Saturation

AbstractOtan-Ile field, located in the transition zone Niger Delta, is characterized by complex structural deformation and faulting which lead to high uncertainties of reservoir properties. These high uncertainties greatly affect the exploration and development of the Otan-Ile field, and thus require proper characterization. Reservoir characterization requires integration of different data such as seismic and well log data, which are used to develop proper reservoir model. Therefore, the objective of this study is to characterize the reservoir sand bodies across the Otan-Ile field and to evaluate the petrophysical parameters using 3-dimension seismic and well log data from four wells. Reservoir sands were delineated using combination of resistivity and gamma ray logs. The estimation of reservoir properties, such as gross thickness, net thickness, volume of shale, porosity, water saturation and hydrocarbon saturation, were done using standard equations. Two horizons (T and U) as well as major and minor faults were mapped across the ‘Otan-Ile’ field. The results show that the average net thickness, volume of shale, porosity, hydrocarbon saturation and permeability across the field are 28.19 m, 15%, 37%, 71% and 26,740.24 md respectively. Two major faults (F1 and F5) dipping in northeastern and northwestern direction were identified. The horizons were characterized by structural closures which can accommodate hydrocarbon were identified. Amplitude maps superimposed on depth-structure map also validate the hydrocarbon potential of the closures on it. This study shows that the integration of 3D seismic and well log data with seismic attribute is a good tool for proper hydrocarbon reservoir characterization.

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