Chemical Classification of Sediments in JVX -Well, Greater Ughelli Depobelt Niger Delta Basin, Nigeria

N Onyeachonam,T.J Fregene

doi:10.4314/jasem.v25i6.17

Abstract

This study evaluate the Chemical classification of sediments in JVX well, Greater Ughelli Depo belt Niger Delta Basin. Samples collected from different intervals were analyzed using geochemical proxies. Agbada Formation was suggested for the sampled intervals due to the presence of shaleand sand intercalations. lithofacies units gotten from sampled intervals are Sand, Shale and Shaly sand facies . The sands are milky in colour, translucent to opaque, medium to coarse grain, subangular to subrounded and are moderately sorted while the shales are Grey in colour,fissile with the presence of lignite streak and calcareous materials.The geochemical studies of the sediments revealed that SiO2 is the dominant oxide followed by Al2O3 and Fe2O3 which constitutes over 90% while others like CaO, K2O, TiO2, Na2O and MgO constitute 10%. The sediments were classified as Fe-shale, Fe-sand and Quartz arenite. Samples that plotted in the quartz arenites region suggests an intense degree of weathering and reworking. The SiO2/Al2O3 ratios for the sediments in the well are appreciably high indicating that the samples have been heavily weathered, evidenced from the enrichment of quartz and depletion of feldspars. Also, the relatively high concentrations of Fe2O3 and TiO2 is an indication of iron-titanium minerals such as haematite and anatase retiles.

Highlights

The combination of source rock, lithologic types, structures and thermal history of the basin are favorable for the generation, accumulation and retention of hydrocarbons (Whiteman, 1982; Stacher, 1995).The mineralogical and chemical composition of clastic sedimentary rocks are controlled by various factors, including :The composition of their source rocks, environmental parameters influencing the weathering of source rocks, Duration of weathering and transportation mechanisms of clastic material from source region to depocenter, depositional environment and Post-depositional processes (e.g diagenesis, metamorphism)
It is a technique used to correlate sedimentary successions based on subtle changes in concentration of key major, minor and trace elements Lucas et al,(2016)
Geology of the Study Area: The Niger Delta Basin, which is the largest sedimentary basins of southern Nigeria, developed along the West Coast of the African continent during the Tertiary times. It is positioned at the intersection of the triple ridge junction in the eastern corner of the Gulf of Guinea from which the rifting and separation of the South American and African continents was initiated

Summary

Introduction

The Niger Delta Basin is economically important because of its petroliferous nature and the economy of Nigeria depends largely on the oil and gas derived from it It is found in the Tertiary period in the geologic column, it lies mainly in the Gulf of Guinea to the southwest of the Benue – Trough and constitutes the most important Cenozoic deltaic construction in the south Atlantic. Geology of the Study Area: The Niger Delta Basin, which is the largest sedimentary basins of southern Nigeria, developed along the West Coast of the African continent during the Tertiary times It is positioned at the intersection of the triple ridge junction in the eastern corner of the Gulf of Guinea from which the rifting and separation of the South American and African continents was initiated.

Objectives

Methods

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Conclusion