Page 34 - Geology and Geochemistry of Oil and Gas

12 SYSTEMS APPROACH IN SCIENCE

object of a study, engineering the systems-related object of activity and optimizing
the process of activity, management, and control.
It is important that the three aforementioned directions are not antagonistic to
each other, but represent the sequential stages in studying geologic systems. First, the
geologic system is identified and studied as a natural geologic body. Then, mostly in
the process of its engineering-technological utilization, it is analyzed and modeled in
order to understand its functions as a natural-engineering system. Eventually, the
system-creating approach merges the analytical and synthetic stages in studying and
developing systems, and is the methodological basis for a cognitive and creative
activity.
The identification of geologic systems and delineation of their boundaries, there-
fore, should be conducted based on the goal stated for each particular situation and
each particular objective of the study. The boundaries of geologic systems may be set
based on different considerations: genetic, regional, the method of engineering-tech-
nological activity, economics, etc. Hence, one of the major tenets of natural sciences,
the relativity principle, manifests itself in the procedure of identifying geologic sys-
tems.
The tentativeness of the geosystem identification follows from the fact that it is an
open system that exchanges matter, energy, and information with the environment.
The information exchange is a determining property of not only geosystems but also
of any natural and engineering-technological (i.e., natural and artificial) systems.
Studies of the structure and behavior of the systems, enables one to obtain scientific
knowledge needed for the engineering-technological utilization of these systems.
As mentioned above, geosystems are open systems. At the same time, closed (but
not isolated) systems are widely used in theoretical and practical geologic studies. In
fact, any theory serving as a model of a geologic phenomenon or process represents a
tentatively closed (quasi-closed) system. Almost all laboratory experiments in ge-
ology, geochemistry, and geophysics are conducted in the framework of quasi-closed
systems, where a researcher has to neglect the effect of environment. An economic
mineral deposit, especially a solid one, is always considered as a closed system. When
developing oil and gas accumulations, one is dealing with quasi-closed systems. This
is especially true if the oil production occurs without the advance of the oil–water
contact (e.g., reservoirs with depletion drive). The concept of the quasi-closed system
allows one to simplify the solution of scientific problems.
An important property of any system is hierarchy of its components. As a rule, it
involves only one characteristic of the classification, namely, its scale. Hierarchically
subordinated components of a system usually differ not in their physical nature, but
in scale. For example, the petroleum basin system may be subdivided into subsys-
tems of oil- and gas-bearing regions, fields, and accumulations consecutively encl-
uded into one another. In this subordination, each one of the subsystems preserves
the general geological and physical features inherent with the system of petroleum
basin.
On the other hand, a unified system (including a geologic system) can contain
elements of different nature, diverse aggregate state, and distinctive physical nature.
As an example, the system of petroleum basin, as well as the subsystems of oil and