UDC 551.25+574

O.V. Savchenko, OJSC “Ukrainian Environmental Research Center”, Donetsk

There is a considerable number of fuel and energy complex facilities (pipelines, oil pumping plants, oil refineries, slurry ponds, storages, filling stations etc.) located in Ukraine. In case of emergency petroleum and its products get into the mountain environment, polluting ground water. Mountain water contaminated with petroleum products can be quite often found as far as dozens kilometers away from its source. Ukraine therefore faces a very acute problem of determining and predicting the migration paths of ground water with petroleum products.

Spreading of petroleum products in rock massifs obeys the laws of formation of underground hydrosphere and flow of ground water. From a hydraulic engineering and hydrogeology point of view [1], natural flow of ground water, as a rule, has a steady, long-term pattern and is governed by cosmogenous, climatic and endogenous factors, while spreading of ground water in the plan view is relatively uniform, the ground water level getting lower towards draining systems (rivers, lakes etc.).

However, the results of exploring natural and technogenic water spreading that have been accumulated in the Open Joint-Stock Company “UkrNTEC” (“Ukrainian Environmental Research Center”) indicate that spreading of ground water has another mechanism [2-4]. The idea of a non-uniform structure of a rock massif which manifests itself in spatial zoning of geodynamic structures [5] therefore underlies the proposed concept of petroleum product migration with ground water.

With ground water spread everywhere, there are identified enhanced filtration zones in water-bearing horizons. Said zones are basically related to geodynamic zones (GDZ), and the filtration regime of ground water depends on geological, particularly geodynamic processes of the earth’s crust [3, 4]. It is in these zones that petroleum products get accumulated in rock massifs. Ground water polluted with petroleum products migrates in both horizontal and subvertical directions along GDZ of rock massifs. Volatile hydrocarbons spread in soil air within the aeration zone and in rock layers near the surface along GDZ, which causes formation of zone halos of pollution with petroleum products and manifests itself as geochemical and geophysical abnormalities.

Geodynamic zones are structural elements of a rock massif with a locally changed stressed and deformed state of rock on the boundaries of tectonic (geodynamic) blocks. GDZ in a rock massif manifests itself in disintegration of physical and mechanical properties, local changes in the tectonic structure and lithologic composition of rock. This results in emergence of water course and gases in soil or more intensive filtration flow of ground water in the water-bearing horizon. On the ground surface GDZ manifests itself fragmentarily or in full, in the form of lineaments – linear geomorphologic structures. From an energy point of view, GDZ is a region of energy flux (energy flux zones) [6] and in terms of anthropogenic impact GDZ is pathogenic or “comfortable”.

Tectonic stresses and deformation of rock in geodynamic zones are transferred to foundations of industrial and civil structures. This leads to early failure of the facilities. The lack of information on a geodynamic state of the rock massif in the foundation of industrial and civil structures enhances the probability of a sudden emergency and consequently a substantial ecological damage by operation of said facilities.

The engineering and geological surveying technique in practice, recommended by regulatory documents, is based on drilling a limited number of boreholes, sampling soil and bedrock, laboratory study of numerous parameters of the latter. Such a technique can not identify GDZ. The OJSC “UkrNTEC” employs therefore geological and geophysical methods, based on the above geodynamic concept, to solve engineering and geological as well as ecological problems aimed at determination of migration paths of ground water with petroleum products.

Generalized experience of many years in geological and geophysical exploration has enabled “UkrNTEC” to come to the following conclusions:

1. The dominating part in formation and migration of halos of ground water pollution with petroleum products is played not only by technogenic factors but also by geodynamic processes. The latter are governed by the structure and geological development of rock massifs.
2. Pressure ground water of rock massifs creates filtration flows of oil-polluted water in GDZ. Under the influence of geodynamic processes, rock in geodynamic zones, particularly in intersection points, gets loosened. Thus the conditions for migration of petroleum products with ground water are created.
3. Spreading of filtrating water from various sources is initially of zoning character and has a dome-shaped pattern. Then it falls outside GDZ, halos of petroleum products pollution formed on large territories.
4. Conventional mapping of pollution halos of petroleum products and their migration paths with the help of boreholes is often ineffective because boreholes are drilled disregarding the location of GDZ, i.e. not in the zones of maximum filtration of oil-polluted ground water.
5. Assessment and prediction of ecological security of territories that are potentially hazardous in terms of halos emergence of petroleum products pollution shall be based on the data of an area and volume structural-geodynamic mapping of a rock massif. Such data can be obtained without drilling boreholes with the help of a geological and geophysical exploration aimed at drawing a map of engineering and geodynamic zoning.
6. Efficiency of actions addressing the determination of pollution halos of petroleum products and their elimination greatly depends on reliability of engineering and geodynamic zoning maps of the territory in question. Said maps would help objectively locate leaks of petroleum products and arrange boreholes for cleaning territories from petroleum products.

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