Introduction
Definition
Integraded Disciplines
History
Applications
Introduction
Integrated
Definition
Disciplines
History
A ‘sequence’ is defined as a ‘stratigraphic unit composed of a
relatively conformable succession of genetically related strata
bounded at its top and base by unconformities or their
correlative conformities.
is a branch of geology that attempts to subdivide and link
sedimentary deposits into unconformity bound units on a
variety of scales and explain these stratigraphic units in terms
of variations in sediment supply and variations in the rate of
change in accommodation space (relative sea level, the
combination of eustatic sea level and tectonic subsidence).
Some aspects of sequence stratigraphy are as old as
geology, but the core originated in the work of early
to mid 20th century.
The subject gained important traction when
adapted and applied to seismic data in the late
1970s.
Subsequent work emphasized concepts of relative
sea-level variations controlling accommodation and
applied these ideas to outcrop-scale systems.
More recent developments include new attempts
to standardize sequence stratigraphy with well-
defined nomenclature and to focus on defining a
sequence stratigraphic method to generate
objective observations, independent of model
assumptions . These observations can then be
interpreted within the framework of a sequence
stratigraphic model to generate useful, testable
predictions.
Oil Natural Gas
Exploration
Ores Water
Sequence stratigraphy is important to study because this
approach to stratigraphic correlation helps geologists
solve real-world problems in the exploration for and
production of resources…whether the resources be
water, coal, oil, or natural gas. In essence, sequence
stratigraphy is a methodology for packaging genetically-
related strata (such as sandstones or limestones and the
associated mudstones) for the purpose of better
describing and reconstructing geological history in
sedimentary basins. In theory, the sequences are
bounded by unconformities or their correlative
conformities.
Sequence stratigraphy allows an effective, systematic
approach to stratigraphic trap exploration. Sequence
stratigraphic concepts provide a means to classify, correlate,
and map sedimentary rocks using time–stratigraphic units.
Sequence stratigraphic techniques provide
(1) a more effective method for evaluating reservoir system
continuity and trend directions and
(2) improved methods for predicting reservoir system,
source, and sealing facies away from well control.
1. The essence of the method is mapping of
strata based on identification of surfaces
which are assumed to represent time lines
(e.g. subaerial unconformities, maximum
flooding surfaces. These events have
economic significance because these
changes in sea level cause large lateral
shifts in the depositional patterns of
seafloor sediments. These lateral shifts in deposition
create alternating layers of good reservoir quality
rock (porous and permeable sands) and poorer-
quality mudstones (capable of providing a reservoir
"seal" to prevent the leakage of any accumulated
hydrocarbons that may have migrated into the
sandstones). Hydrocarbon prospectors look for
places in the world where porous and permeable
sands are overlain by low permeability rocks, and
where conditions are right for hydrocarbons to be
generated and migrate into these "traps".
In Low stand system tract,
In early sea level rise, sea water moves
landward taking anything in its way
such as plants, animal remains, shark
teeth and so on....and precipate them
in depressions and with time converted
into ecnomic ore such as phosphate ,
Gluconite , Iron.... Etc.
