Kerogen analyses of sediments in the Lamu embayment Kenya

Results of numerous wells drilled by BP-Shell Petroleum
Development Company of Kenya between 1963 and 1971 within the
Lamu Embayment, as confidential Geological Completion Reports
indicate, gave hydrocarbon gas shows in Walu, Dodori and Pate
wells. To investigate possible origin of these gases, the
kerogen quality, quantity and maturation in these wells' samples
were systematically evaluated.
The study has shown that the percentage kerogen within
the Lamu Embayment sediment is more than the minimum required to
yield commercial accumulations on maturation. The results
indicate that the quantity of kerogen within these sediments
varies with age and the type of lithology. Calcareous mudstones
and shales of lower Cretaceous together with bituminous mudstones
and lignite interbeds within sandstones of upper Eocene
constitute the organic ric6 sediments.
The study also revealed the presence of two types of
kerogen; the amorphous and the humic types which are the 011 and
gas generating types, re~pectively.
Kerogen colour and the percentage of fixed carbon ratio both show
that some kerogenous matter within source sediments in the study
area is mature. No attempt was made to establish whether
hydrocarbons have migrated-from these source rocks.
However,maturation boundaries have been located in the middle
Eocene for Dodori and Pate wells at depth qreater than 2000 m ,
Further inland, at Walu, mature kerogen was noted within the
cretaceous sediments from depths slightly more than 1500 m.
With enouqh mature percentaqe keroqen within the Lamu
Embayment, results of this work give a new dimension as regards
the petroleum potentiality of the area.
-College of Biological and Physical Sciences (CBPS) [3264]