Abstract
This study is aimed at enhancing characterization of deepwater reservoir sands as a way of de-risking the exploration prospect in “N” field. The data used for the analysis consist of logs from suites of four wells. The petrophysical analysis of the two reservoirs (RES-1 and RES-2) of interest revealed that reservoir (RES-1) has fair to good petrophysical attributes while reservoir (RES-2) has good to excellent petrophysical attributes. Statistical relationships between compressional and shear velocity (Vp and Vs) were evaluated from dipole sonic log present in N-002 well using linear regression analysis. This localized relation with a correlation coefficient of 0.96 predicts VS from VP with high level of precision and fits a large population analysis of the wells. Compaction studies revealed that at depth of 3.2 km, quartz cementation of sands and velocity of sandstones became higher than that of shales. This depth represents a transition from mechanical to chemical compaction zone and therefore represents a significant seismic boundary in the studied field. Porosity-velocity crossplot of the reservoir sands revealed that only reservoir sand data points which contained 30 to 40% porosity plunge across the 15% clay line with most data points falling between 0.25 and 0.35 fraction and below 0.35 clay trend lines. This suggest high clay fraction within the sediments. Rock physics templates of constant, contact and friable showed that the reservoir sands are poorly cemented to unconsolidated. The two models indicate that the reservoir sands are both influenced by depositional and depth related diagenetic effects. This suggests that proper care has to be taken during the development of these reservoir sands due to high clay fraction which could affect oil and gas production.
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22 February 2022
A Correction to this paper has been published: https://doi.org/10.1007/s12517-022-09697-w
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Responsible Editor: Narasimman Sundararajan
The original online version of this article was revised: In this article the author names were incorrectly given as “Akinyemi, Oluwaseun Daniel, Ayuk, Michael Ayuk” but should have been “Oluwaseun Daniel Akinyemi, Michael Ayuk Ayuk”.
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Akinyemi, O.D., Ayuk, M.A. Rock physics analysis as a tool for enhancing characterization of Niger Delta deep water sands. Arab J Geosci 15, 98 (2022). https://doi.org/10.1007/s12517-021-09370-8
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DOI: https://doi.org/10.1007/s12517-021-09370-8