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1. APPLICATION OF FORAMINIFERA IN
OIL EXPLORATION
Presented By:-
Purva Pandey
M.Tech DHSGSU

2. CONTENT
(1) Introduction
 Brief Introduction of microfossil and their application
 Role of foraminifera in oil exploration
(2) Condition for oil formation.
 Process of formation of oil
(3) Concept of foraminiferal use in oil exploration
 Biostratigraphy based analysis of sedimentary basin
• Biostratigraphic coyrreletion
• Biozone and Higher Resolution stratigraphy
 Stratigraphic correletion
 Interpretation of paleoenvironment
 Seiesmic Stratigraphy
 Geohistory Analysis
(4) Micropaleontological Techniques
(5) Conclusion

3. Micropaleontology has been utilized as important tool
and proved as one of the major branch of study in
exploration mainly for crucial and economically valuable
oil exploration , But exploration also depend upon many
other studies (Branches) like geochemistry
sedimentology,stratigraphy,oceanography etc to reach to a
final destination/finding in oil exploration.
ROLE OF MICROFOSSIL IN OIL EXPLORATION:-
The Micro-fossils, because of their
small sizes, can be collected even from the cores of the
bore holes. A large number of microfossils can be
collected from a relatively small number of rock samples
thus giving a much wider spectrum of data.
DIATOMS
FORAMINIFERA
OSTRACODA
COCCOLITHOPHORE
RADIOLARIA
CONODONT
INTRODUCTION

4. Brief Introduction about Foraminifera:-
• Foraminifera (Protozoa) derived from Latin word means
‘hole bearer’ .foram are unicellular organism with hard
shell called 'Test' , They derived their name from 'Foremen '
the pores connecting the chambers in the test .they vary in
size from less than millimeter (smaller or micro
foraminifera ) to as large as 100 mm. common in brackish
and marine environment
Why forAminiferA plAys importAnt role in oil explorAtion:-
• Being exclusively marine , except a few spices highly
abundant in deep sea sediments/rocks ,very sensitive to
even minutes changes in environment foraminifera have
wide application in stratigraphic correlation ,higher
resolution Biostratigraphy , oil exploration,
environmental interpretation.

5. CONDITION FOR OIL FORMATION :-
Primary environment required for conversion of
organic matter into oil are :-
 Sediments if deposited at high rate (generally in estuaries ),cover
organisms before they are bacterially destroyed / oxidised and thus
favour formation of oil .
 Usually a high current index is not favourable for generation of
petroleum as it allows of oxygen that oxidizes the oil – forming
organisms ;
High degree of reducing conditions prevents oxidation of organisms
and favour conversion of organic matter into oil .
 Compaction of sediments during palingenesis is favourable fir the
formation of an oil pool .

7. Process of formation of oil

8. Concept of foraminiferal use in oil exploration
•
(1) Biostratigraphy based Geologic history of sedimentary basin
Biostratigraphy is the element of stratigraphy that deals with the remain or evidence of former life in a
strata and with the organisation of Strata into unit based on their fossil content .there are some specific
point about their Biostratigraphic correlation .
• Strata are characterized by their Fossil content
• Organize into unit based on fossil Characteristics
• Not large as mega fossil but not rare.
• Fossil are extremely common in marine environment ,infect they are the main constituent in many cases.
• Organism are sensitive to their environment
• Live where they are comfortable
• We can use their relationship to determine something about the environment .
• Biostratigraphy is based on Appearance and disappearance of spices.
• Spices appeared (evolved) or disappeared (extinct ). Globally .

9.  BIOSTRATIGRAPHIC CORELATION
Biostratigraphy is the grouping of strata into units based on their fossil content with the aim
of zonationand correlation.
It include :
 Identification of taxa
Tracing their lateral and vertical extent
Dividing the geological columnn into units defined on their fossil content
Role of microfossil in biostratigraphy??
Microfossils are among the best fossils for biostratigraphical analysis because they can be
extremely abundant in rocks (a particular consideration when dealing with drill cuttings)
and they can be extracted by relatively simple bulk processing methods.
DATUM PLANE : –
A Datum plane / boundary of biostragraphic change of distinctive Characters (marker
species) based on abrupt evolutionary appearance i.e., first appearance Datum (FAD) or
Last Appearance Datum (LAD) should be a Conspicusous Paleontological event
correlatable and isochoronous over relationable distances.

10. BIOZONE
BIOZONE is the lowest unit of a biostratigraphic classification at a regional level for any kind of
biostratigraphIc unit, where upper and lower limits are defined by Datum planes
. BIOZONE (often just "zone"): Rock unit characterized by one or more taxa that permit
it to be distinguished from adjacent rocks ,may be defined as:
(1) Range zone – Represent then stratigraphic range of one spices , a group of one spices , a lineage and
may be recognised as ‘’TAXON RANGE ZONE’ and ‘CONCURRENT ZONE ‘ and ‘LINEAGE
ZONE’
• Taxon range zone - lower and upper limit of zones are defined by lowest and highest occurance of zonal name bear
• Concurrent zone– zone boundaries defined by the overlapping of 2 or more taxa.
(2) Interval zone - it is a gap between 2 distinctive Biostratigraphic Horizon and its not itsself a range zone
of any taxone. It recognised on the basis of absense of a particular distinctive biostratigraphic assembly or
feature during the span when the rocks were deposited

11. (3) Assemblage-zone :-
A body of strata whose content
of fosils or certain fossils taken in its
entirety , constitutes a natural
assemblage or association that help
distinguishing it in biostratigraphic
character from adjacent strata.
(4)Acme –zone:-
is a body of strata
representing maximum development of
some species , genus , or other taxon ,
but not its total range

12. (2) STRATIGRAPHIC CORELATION
• In the Global and Local corelation such as from ‘well to well’. Foraminifera provide some important information .for the two well are located in the
same sedimentary basin,there are some methods for correlation between well A and B.
• one is comparison of the changes of planktonic and benthic formaminiferal –ratio(P/B ratio) between them .the ratio is calculated as follows.
Ratio of P/B of 20:1 shows depth of 200 m or more.
The ratio indicates degree of open –ocean influence , a high value means that whole sedimentary basin was under such influence .
Because these influence affect most (flagpole) of an entire basin in the same way ,changes in the P/B ratio are useful indicator for well –to-well correlation .
Another method is a ratio of aranaceous and calcerous bethhic foraminifera (A/C)
This ratio is calculated as follows :-
Arenaceous foraminiferal number
Total benthic formaminiferal number
•In this case the high value of this ratio indicates a stagnent environment in the basin.
100planktonic foraminiferal number
Planktonic formaminiferal number+benthic formaminiferal number
100

13. (3) Interpretation of paleoenvironment:-
Paleoenvironment analysis is the interpretation of the depositional environment in which the rock unit is formed, based
upon the fossil found within the unit. Most of the micofaunna can be great help in visualising the environment(Provenance)
at the time of their deposition .Examples are :-
(1) LACUSTRINE ENVIRONMENT – Diatoms and rare occurance of foraminifera
(2) LITTORAL ENVIRONMENT – sessile foraminifera and ostracoda
(3) LAGGOONAL ENVIRONMENT – spores and pollens, conodont,arenaceous,and porcelaneous foreaminifera .
Through paleoenvironment analysis the fluctuation in sea level can be reconstructed by initially inferring the
paleobathymertry and then integrating in the same on regional stratigraphy for thr reconstruction the
transgressive/regressive cycle within a time .
The distribution parrerns of benthic, planktic , calcareous ,and agglutinated species indicate the marsh,
beach, channel, lagoon ineer and outer neritic , bathyal and abyssal regions respectively. The marshy fauna is dominated
by simple agglutinated taxxa. The lagoonal facies of rocks is characterized by similar euryhanline fauna and dominated
by species like Ammomia , Elphidiumand Quinqueloculina. The coastal shelf fauna is dominated by benthic species.
The simple agglutinated speies indicate bay an laggonal enviroments.`

14. Murray’s model for paleoenvironment
• Murry (1977): triangular models (Interpretations of salinities or
paleo –salinities based on textulariina , Milliolina & Rotaliina.
• Summary
. It is directly relatedto their vital activities . Each species has certain
critical as well as optimum salinity-limits for various physiographic
functions.
.Affects the physiogeographic distribution.
. There is unifrom distribution of salinity in opes seas . So this effect is
much more pronounced where there is considerable mixing with
fresh water .
.Seasonal variation also affects distributiom& occurrence.
.It affect test morphology, size & ornamentation. Generally reduction in
size &loss of ornamentation is observed near & salinity tolerance
limits.

15. The Rate of sedimentation
Delineation of boundaries between Outer bay and inner bay facie in a
succession ,On the basic of
• Calceroua vs agglutinated ratio
• Ecophenotype of calcerous species
Two morphological form, with in same species representing contrasting
environmental conditions E.g Foram A and Foram B in ammonia
parkinsonina In Indian water Indicating low and high salinity condition
respectively. The brackish water fauna generally consista of
cosmopoltian species. Outerbay facies and inner bay facis may be
demareated on the basis of ratio of Ammonia –Elphidium and ‘
Ammonia –Ammobaculites ( or calcareous –
agglutinated).Ecophenotypes of calcareous species help delineating ‘
outer – bay and inner – bay facies in much better way in comparsion to
the calcareous – agglutinated ratio required in petroleum exploration .
RATIO OF ECEOPHENOTYPE IN CALCEROUS SPECIES
ECOPHENOTYPE – two morphological form With in single spices give better result.
Number of test of foram A
*100
Number of test of foram A &B

16.  Basic of elongated and rounded form
• Elongated form show calm water .
• Rounded form shows Agitated water zones with High
aeration .
Elongated form example :-
1. Nodosaria
2. Bigenerina
Rounded form example :-
1. Conuspira planispiral
2. Overculina
So on the basis of foraminifera we can intimate the idea of
water condition so calm water condition is most preferable
for oil formation

17. (1) Recognition of geologic phenomena :
Uncnformities ,Sea level changes etc. are usually reflected in lithofacies.The data helps studying the Causes of Geologic phenomena.In a
general sense there are two types. Unconformities:
(a) Subaerial erosion (reflected in distinctive lithofacies)
(b) subaqueous erosion (sometimes unrecognised as a change of lithofacies also called non deposition.
(2) Subaerial erosion - Subaerial erosion may be marked by lithofacies change between the rock below the rock below the unc and the basal
conglomerate.
(3) Lithozonation – as it’s obvious limits on other hand criteria may Help achieving better/higher resolution e.g magnetozones , biozone is and
imiginary succession
(4) Non deposition and subaqueous erosion – A lot of information on Deep sea sediments has published for e.g. Presence of deep sea hiatus
were detected at many sites .if both the benthic formaminiferal Assemblage and the lithofacies are unchanged across the unc it indicates that the
paleo water depth was constant .
Deep sea hiatus are caused by changes in bottom current ,If the bottom current velocity is fast,the grains move instead of being deposite So the
direction of bottom current is indicated by tracing the presence of the hiatus at a number sites .
(5) Cyclothem – In a case study of carboniferous the fosssil evidence showed a paleoenvironmental change from non marine,near shore,off
shore and finally to near shore within each cyclothem ,some individuals beds within the cyclothem could be traced for more than 300 km .it
seems likely that cyclothem are the product of eustatic sea level fluctuations induced by repeated glaciation.
(6) Faunal change – in the upper Cenozoic sediments various methods have been employed for the analysis of paleoenvironment. In a case
study the sea -level fluctuations and climatic events were analysed using foraminiferal assembled in the southern Gulf of Mexico.

18. (3) Seismic stratigraphy –
Sedimentation, responding to change in sea level ,has produced a stratigraphic record by
shaping sedimentary sequence that can be studied by Seismic reflection . However ,it’s
necessary to compare Seismic data with Paleontological data to determine global change in
sea level.
(4) Geohistory analysis –
with the understanding of the Characteristics of microfossil And how to use them analyse
Geological ageS And paleoenvironment a numbers Paleontological properties( age in
years and water depth in meters) Is used in Numerical stratigraphy is called geohistory
analysis .

19. Micropaleontological Techniques
For petroleum exploration, apart from the
study ofsureface samples are collected from
exploratiory wells , which may be of the
following three types
1. Cutting sample
2. Conventional Core(CC)
3. Side wall Core (SWC)
Depending upon the requirement
of sample at different depth amd length
of sea or lake floor sediment these
instruments are deployed
 Van veen Grab sampler
 Spade corer
 Multi corer
 Gravity corer

20. Reference
• (1) Haq, B.U. and A. Boersma, (eds.). 1978. Introduction to Marine Micropaleontology.
Elsevier, New York. 376 pp.
• Baker, R. 1979. A Primer of Oilwell Drilling. Petroleum Extension Service, the Univ.
of Texas at Austin, Austin. 94 pp.
• Martin F Glassener 1972 ,principles of micropaleontology ,hafner Publishing Company
99pp