Ethan Frome

Главная страница UDC 550.83:622.7
ECOLOGICAL GEOPHYSICS AND POTENTIAL PREVENTION OF NATURAL AND TECHNOGENIC EMERGENCY SITUATIONS

AT MAIN PIPELINES

E.G. Sobolev, B.I. Voevoda, A.V. Savchenko, G.A. Petenko, E.P. Takhtamirov, A.N. Russanov – OJSC “Ukrainian Environmental Research Center” (UkrNTEC), Donetsk

The Open Joint-Stock Company “UkrNTEC” has developed some sets of ecological geophysics methods for assessment of geodynamic processes of the geological environment that affect a technogenic and ecological operational safety of main pipelines and auxiliary structures (oil and gas pumping plants).

Depending on geophysical survey conditions (asphalt pavement, rock outcrop, electromagnetic interference), the most rational (optimum) complex of ecological geophysics methods is selected.

The principal document that geological and geophysical exploration yields is a map of engineering and geodynamic zoning. Based on the map data, potential emergency sites are identified, an emergency situation development predicted, rational protection actions aimed at its prevention worked out and the results of undertaking said actions controlled.

Geological and geophysical exploration is carried out by stages and in succession, various types of geophysical methods employed and different physical parameters of the geological environment studied, which guarantees a reliable solution of a number of tasks ensuring the achievement of the goal set, namely prevention of emergency situations at pipelines and on operation sites (Table 1).

The tasks to be addressed somewhat differ, depending on exploration objects (pipelines or operating sites).

Thus, in exploration of the geological environment along the pipeline route the following basic tasks need to be solved:

identification of tectonic faults and intersection points of microgeodynamic zones and assessment of geodynamic activity of the latter within the pipeline location (Fig. 1);

exploration of ravine and gully sections of the pipeline route and assessment of the soil slip hazard of sloping sites (Fig. 2);

exploration of pipeline route sections on the territory with underworked roadways (including the flooded ones).

Table 1. Ensuring Technogenic and Ecological Operational Safety of Main Pipelines with the Help of Ecological Geophysics Methods (UkrNTEC’s technique)

Item	Types of work	Parameters under study	Tasks to be addressed
Stage 1. Reconnaissance
1	Preliminary analysis:
1	1.1 Geomorphologic analysis of terrain, analysis of the geological structure.	Surface elevation, geology of the region.	Identification of lineaments (prediction of geodynamic zones) as well as their intersection points along the pipeline route and on operation sites.
2	Exploration of massif geodynamics:
	2.1 Magnetodynamic introscopy of near-surface layers of the Earth, based on profiles along the route.	Full vector of geomagnetic induction.	Identification of structural heterogeneity in the near-surface layer of the Earth (geodynamic zones, tectonic faults, loose and flooded soil sites, leaks of petroleum products in plan etc.).
	2.2 Radiometric survey.	Concentration of the gases radon and toron.	Determination of geodynamic zones’ activity and tectonic faults.
	2.3 Radiometric survey on rock and pavement (with the use of UkrNTEC’s technique and equipment).	Intensity of alpha radiation as a result of decay of the radioactive gas radon.	Determination of geodynamic zones’ activity, tectonic faults, flooded areas beneath asphalt pavement, in rock massifs and ash disposal areas.
	2.4 Structural geodynamic azimuthal mapping.	Soil conduction, vector indices.	Identification and azimuthal mapping in plan of tectonic faults and geodynamic zones.
3	Soil corrosiveness study:
	3.1 Electroprofiling of soil, comprising pipes.	Soil electric resistance.	Identification of route sections where soil exhibits higher corrosiveness (GOST (state standard) 9.602-89), sites with lithological change of rock, faults and different water content etc.
	3.2 Gas survey along the same profiles.	Carbon dioxide and methane.	Identification of sites with lithological change of rock and faults.
4	Drawing a reconnaissance map of engineering and geodynamic zoning of a main pipeline site.
Stage 2. Detailed exploration
5	Detail exploration of zones identified in stage 1:
	5.1 Vertical electric sounding of upper layers of the Earth (the spacing along the profile is 10-20 m).	Soil electric resistance, longitudinal conductance, lateral conductance.	determination of the depth of occurrence of natural technogenic ground water; determination of the soil slip plane and its depth of occurrence on the soil slip hazardous slope (GOST 17.1.3.10-83); defining exact boundaries of geological heterogeneity.
	5.2 Linear-orthogonal electric sounding.	Soil electric resistance, longitudinal conductance.	Exploration of a vertical hydrogeological section on operation sites with asphalt and concrete pavement.
	5.3 Routine radiometric exploration at geodynamic structures that present a soil slip hazard.	Intensity of alpha radiation as a result of decay of the radioactive gas radon.	Assessment of a geodynamic activity of soil slip structures. Differentiation of massifs by types of deformation: compression, tension. Determination of the alpha radiation activity of rock massifs and massifs with pavements (using the technique and equipment “RIGDA-1,2” developed in UkrNTEC).
Stage 3. Drawing a detailed map of engineering and geodynamic zoning of the main pipeline route site
6	Laboratory work:
6	6.1 Generalization of geological and geophysical exploration results, drawing a detailed map.		Development of recommendations on ensuring technogenic and ecological operational safety of pipeline route sections and operation sites.
Stage 4. Control over the massif geodynamic state.
7	Prediction of massif activation:
7	7.1 Routine observation at emergency hazardous sections.	The above-mentioned geophysical parameters.	Prevention of emergencies in pipelines or on operation sites.

In exploration of main pipeline maintenance sites the following tasks need to be solved:

study into the processes of operation site flooding;

ascertainment of causes for loss of stability of industrial and civil facilities;

detection of hidden (underground) leaks of petroleum and its products from combustibles and lubricants storages as well as main pipelines;

detection of emergency hazardous sections of dikes (dams) of slurry ponds.

Selection of geophysical methods depends on lithological characteristics and state of the massif under exploration and its surface layer.

In case of loose deposits of massifs (the soil-vegetable layer) the rational complex of geophysical methods would comprise the following:

magnetodynamic introscopy of rock (a MM-60 magnetometer employed);

vertical electric sounding (“ERA-89”);

radiometric survey (“RADON”).

The above set of methods is also used in exploration of loose fill-up soil.

In case of rock or pavements the complex of methods would incorporate the following:

magnetodynamic introscopy of rock (a MM-60 magnetometer employed);

linear-orthogonal electric sounding (contactless measurement of electric current) (“ERA-89”);

structural geodynamic azimuthal mapping (“EFA”);

radiometric survey (“RIGDA”).

The same complex is applied in exploration of rock fill-up soil.

The ecological geophysics methods feature high mobility, low cost and can be employed under any mining and geological as well as weather conditions. The use of said methods would yield an adequate ecological and technical operation of the existing main pipelines as well as allow to identify the most appropriate sites for laying pipelines and construction of new projects on operation sites.