Journal of Petroleum Geology, Vol.10,
No.1, pp. 101-114, 1987
©Copyright 2000 Scientific Press,
Ltd.
MINERALOGICAL AND
GEOCHEMICAL STUDIES OF TERTIARY SEDIMENTS FROM THE EASTERN NIGER
DELTA AND THEIR RELATIONSHIP TO PETROLEUM OCCURRENCE
Minapuye I. Odigi*
*Geology Department, Faculty of
Science, University of Port Harcourt, PMB 5323, Port Harcourt,
Nigeria.
Abstract
Mineralogical and chemical studies have
been made of shale cuttings from the Akiri-1 well in
Oligocene--Miocene sediments of the Niger Delta. The
micromillimeter fraction from the 2,183 to 3,720m stratigraphic
interval was analyzed by X-ray diffraction. Kaolinite and
chlorite are more abundant than other clay minerals. The
illite/smectite composition changes from a phase with 32% illite
layers, to one with 82% illite layers over the 3,250 to 3,720m
stratigraphic interval. Kaolinite decreased in shallow shales
from 22 to 16% and increases to 29% in deep shales. Quartz
increases in abundance with depth, while chlorite and plagioclase
feldspar show no systematic trend with depth. Calcite is present
in small amounts in all the samples.
