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Biostratigraphic services include micropaleontology (foraminifera), calcareous nanoplankton,
palynology, palynofacies, wellsite biostratigraphy, stratigraphic reviews, correlation
studies and multi-disciplinary integrated studies. Core Laboratories is increasingly
involved in high-resolution biostratigraphy and palynofacies/biofacies studies fully
integrated with seismic, wireline log and sedimentological or lithofacies data.
The resulting sequence stratigraphic interpretation gives a much fuller geological
understanding of the sedimentary section than that provided by biostratigraphy alone.
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Foraminferal and Calcareous Nannoplankton Analyses
It is important to date a micropalaeontological assemblage in terms of
standard biozones and necessary to recognise stratigraphically significant rock
units based on their micropalaeontological assemblage for interwell correlation.
Micropalaeontological and palynological assemblages can also be used to assess the
depositional environment since different microfauna are found associated with different
water depths. This data is valuable for geological and reservoir modeling since
the depositional environment dictates the likely sand geometry, continuity and reservoir
quality. Similarly in carbonate environments the recognition of fore reef, back
reef, or lagoonal facies is important for predicting the most likely location for
the reef.
Semi-quantitative analysis refers to visually estimated abundances and is recommended
for basic interpretation of age and depositional environment. Quantitative analysis
provides absolute counts and is particularly useful for detailed, high resolution
biostratigraphic studies in a sequence stratigraphic framework.
Palynofacies Analysis
Detailed palynofacies determination can be of great value for correlation and assist
in defining sequence stratigraphic events by putting the relatively few taxonomically
based palynological marker events in the correct stratigraphic context.Palynofacies
analysis allows the identification of distinct palynosequences bounded by "key"
stratal surfaces of regional and/or local sequence stratigraphic significance. Correlatable
stratal surfaces often prove to be coincident with (and enable more accurate picking
of) seismic events in well sections. Stratal surfaces recognised from palynofacies
associations have been proven to form an invaluable framework within which each
palynology event can be seen in its geological context.All this can be achieved
independently of, for example, lithofacies, electrofacies and sedimentology. If,
however, palynofacies is integrated with other disciplines its effectiveness can
be considerably enhanced.
Wellsite Biostratigraphy
Both micropaleontological and palynological analyses can be performed at the wellsite
in self-contained units both on and offshore. The data gathered can be invaluable
for quick evaluation of age and environment of the formations drilled. Wellsite
data may also be useful for biosteering in horizontal wells where vertical variations
in palynomorph character allows real-time adjustment to bit trajectory to keep the
well on target.
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