Earth, Energy & Environment

Earth, Energy & Environment

LITHOSTRATIGRAPHY AND RESERVOIR QUALITY OF THE AJALI SANDSTONE AT UDI, ANAMBRA BASIN, SE NIGERIA.

Pages: 14  ,  Volume: 5  ,  Issue: 2 , May   2018
Received: 01 Jun 2018  ,  Published: 03 June 2018
Views: 50  ,  Download: 34

Authors

# Author Name
1 Agbo, C.C. and Uzoegbu, M.U.

Abstract

ABSTRACT

The studied area lies within the Anambra Basin and is bounded by latitude 6°21?45 ? and 6°28?00 ? N and Longitude 7°23?45 ? and 7°28?00 ? E and it covers an area of about 73.70km2. The area is characterized by two formations, the Mamu Formation and the Ajali Sandstones. The Ajali sandstone overlay the Mamu Formation. Both formations are of Maastrichtian age. The Mamu Formation is consists of shale with some occurrences of coal. Five lithologic units were observed in the Ajali Sandstone. These include the coarse – pebbly grained facies (basal); cross – stratified, medium – coarse grained facies; fine – medium grained facies; siltstone/shale facies; and coal/carbonaceous mud facies unit. Sedimentary structures observed include planar cross-beds, beddings and ravinement surfaces. In the paleoenvironmental reconstruction using pebble morphology and paleocurrent analysis, both indicated a high energy fluvial environment. From the sieve analysis, the four samples collected from the four locations are poorly to well sorted, symmetrical to very negatively skewed, fine to medium grained and its kurtosis ranges from mesokuritc to very leptokurtic. The Ajali Sandstone is the main aquiferous unit in the area. Geologic deposits of economic significance found in the area include ferruginized sandstone, cemented sandstone, and coal. The sandstone indicated excellent reservoir qualities with high porosity and permeability.

Keywords

References

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