Page 35 - Geology and Geochemistry of Oil and Gas

SYSTEMS APPROACH IN PETROLEUM GEOLOGY 13
gas regions, fields, and accumulations, contains such components as (1) reservoirs;
(2) seals (caprocks); (3) formation fluids (oil, gas, water); (4) tectonic, stratigraphic,
lithologic, and other barriers, etc. In the above short list, no attempt was made to
compare the system components for their complementarity, which would be nec-
essary in order to emphasize their physical distinctions. Obviously such system’s
components are also the subsystems of the original system. Such hierarchy would be
substantially different from a hierarchy based on the subsystem’s scale and, to some
degree, its complexity. One example of such an approach to the hierarchy of a
megasystem is the classification of oil and gas accumulation traps (Fig. 1.1)
(Kerimov, 1985).
If geology is defined as a complex of scientific disciplines dealing with the com-
position, structure and evolution of the Earth’s crust and the Earth as a whole, then
it would be natural to subdivide the objects of geologic science disciplines into
the static and dynamic ones depending on time considerations. In static, matter-
structural problems, the time is set, whereas in dynamic problems, the time changes,
in a discrete or continuous way, non-periodically or cyclically depending on the
specific geologic process of interest.
The existence and functioning of dynamic geologic systems is controlled by var-
ious processes, which depend on diverse natural factors. The dynamic systems, which

Fig. 1.1. Oil and gas area static system (modified after Kerimov, 1985).