KEY PROBLEMS OF HYDROGEOLOGY AND HYDROGEOCHEMISTRY OF TOMSK OBLAST AND ADJACENT TERRITORIES

P. A. UDODOV, N. M. RASSKAZOV, A. D. NAZAROV

Before characterizing the principal tasks in the field of studying and using the groundwater of the Upper and Middle Ob basin, it is necessary to dwell briefly on the main results and shortcomings of its investigation.

The most important fact should be considered the identification of the main aquifers and complexes that are of practical interest for organizing domestic and drinking-water supply, and the assessment of their resources—unfortunately, without taking into account their replenishment from surface watercourses. Thus, for example, it has been established that drinking waters characterized by large reserves are associated with sandy horizons of the Paleogene and Cretaceous, gravel-pebble alluvial deposits, Jurassic conglomerates, sandstones, and Paleozoic limestones. Increased water abundance has also been established in fracture zones in the basement rocks. It has been shown that, in all these complexes, the most water-bearing areas are those located in river valleys or adjoining them.

With competent operation, the groundwater of the horizons mentioned can be successfully used not only to supply small facilities, but also to organize centralized water supply for cities and other populated places. As an example, one may point to the districts of large industrial facilities in the south of Tomsk Oblast and certain cities of Kuzbass, where significant reserves of groundwater have been explored and are already partly being exploited [2, 3].

Groundwater of the region has been recommended in a number of areas for use in irrigating arid territories. The feasibility of these recommendations is evidenced by preliminary data obtained by the West Siberian, Novosibirsk, and Tomsk geological administrations, the Vostokburvod trust, the Siberian Branch of the Academy of Sciences of the USSR, and several other organizations. However, for a final positive resolution of this question it is necessary above all to evaluate the resources and reserves of these waters in high categories and to have them approved by the TKZ.

In the course of oil-exploration work, thermal waters occurring at depths of more than 1000 m within the West Siberian Lowland have been discovered; as a rule, these waters are mineral (medicinal). These waters, which have large reserves, are used in Omsk Oblast for heating premises, for constructing swimming pools, and for medical treatment of the population. This experience deserves the most vigorous support, and it must be extended to neighboring oblasts—first and foremost Tomsk Oblast.

Thermal waters have also been established on the periphery of the lowland, in

in the bedrock surrounding its mountain massifs. New deposits of these waters may be discovered here. In the area of the city of Tomsk, for example, thermal radon waters are expected to occur at a depth of more than 1000 m. We substantiate this position by taking into account the features of the geological structure of this sector. Similar assumptions were also expressed by Prof. A. M. Ovchinnikov [5, 8].

Geological investigations carried out recently by various organizations within the southeastern part of Western Siberia have made it possible to identify here various types of mineral waters and to compile maps of their distribution within individual oblasts. To date, radon waters (hot and cold), carbon dioxide waters, methane waters, hot hydrogen-sulfide waters, iodine-bromine waters, siliceous waters, ferruginous waters, and other types of mineral waters have been identified [1, 2, 4]. It has also been established in the course of investigations conducted by the Tomsk Polytechnic and medical institutes that the peat waters and peats of Western Siberia possess medicinal properties; their reserves are practically unlimited [6].

For a long time, hydrogeochemical investigations have been carried out in the region under consideration in connection with prospecting for mineral deposits, based mainly on a thorough study of the macro- and microcomponent composition of natural (ground) waters. In the course of these investigations, areas promising for polymetals, cobalt, and mercury were identified. At some of them, deposits of the corresponding metals have now been discovered. The most substantial hydrogeochemical work in terms of volume has been carried out in the Kolyvan–Tomsk folded zone, the Kuznetsk Alatau, the Sayan Mountains, Gornaya Shoria, and Kuzbass [8].

In the course of these works it was also established that in certain populated localities waters with elevated contents of some heavy metals are used for drinking.

Considerable work has been carried out by NSTU, ZapSibNIGNI, TPI, TTGU, SNIIGGiMS, and other organizations in studying the chemical composition of oil-field waters. At the same time, the introduction into practice of paleohydrogeological investigations has begun [2, 3].

The materials accumulated in the course of these investigations, together with those obtained by other scientific and production organizations in Western and Eastern Siberia, have been used to compile a hydrogeochemical map of Siberia. Its creation will contribute to the further development of hydrogeochemical work.

During 1963–67, the Tomsk Polytechnic Institute, jointly with the institute “Giprotorforazvedka” and the Novosibirsk Geological Administration, carried out hydrogeological and hydrogeochemical investigations within the peat massifs of the southeast of Western Siberia. Their principal result should be considered the development of a methodology for hydrogeological investigations at various stages of exploration of peat deposits [7].

Considerable work has been carried out by ZSGU, NSTU, TTGU, TPI, ZapSibNIGNI, and other organizations in studying the hydrogeological conditions of deposits of various mineral resources, as a result of which the conditions for their exploitation have been assessed. Very valuable data were obtained by the ZapSibNIGNI institute in studying the groundwater of the West Siberian artesian basin and clarifying the possibilities of using it for water injection during the development of oil fields, iodine extraction, domestic and drinking water supply, development of health-resort construction, and other purposes [2].

However, it is necessary to note that in the study and use of the groundwater of the territory under consideration there are a number of shortcomings.

…that have an adverse effect when many national-economic tasks are being addressed. In our view, the principal ones are the following.

First of all, it should be noted that neither the resources nor the forecast exploitable reserves of the aquifer complexes (horizons) most promising for the organization of centralized water supply—occurring at depths down to the first hundreds of meters, with provision for their replenishment from surface watercourses, primarily large ones—have been evaluated. If one also takes into account that the categorized exploitable reserves of groundwater have been calculated and approved by the GKZ for a very limited number of sites, then the weak use of these waters for large-scale water supply, especially in the central and northern parts of the territory under consideration, cannot be regarded as accidental.

At the same time, it must be noted that the organizations conducting groundwater exploration either are not equipped with modern equipment for the rapid drilling of hydrogeological wells in loose rocks without clay mud, or have not mastered the technique of such drilling. This leads to the fact that wells penetrating sandy horizons, even after the application of any of the known methods of declaying, yield substantially reduced water inflows in comparison with wells drilled without clay mud. A vast body of factual material (from more than 800 wells), confirming this well-known proposition, is presented in the dissertation of G. G. Kvashnin, chief engineer of the Vostokburvod trust, where the results of experiments on declaying are also set forth, and in the reports of a number of hydrogeological parties. A reduction in well yield is caused, in addition, by the absence of filters that would ensure reliable operation in the sands of exploratory hydrogeological wells, which have a relatively small diameter. The shortcomings indicated lead to the fact that, in the course of exploration, groundwater reserves obtained are clearly underestimated in comparison with those that exist in reality.

Cases are noted of poor-quality equipment of production wells and of their untimely abandonment, which leads to contamination of aquifers. This is clearly evidenced by data obtained by the Tomsk Oblast Sanitary-Epidemiological Station and other institutions.

Familiarization with the results of work carried out by specialized organizations for the construction of production water wells shows that, as a rule, they do not check the correctness of the choice of the interval for installing the filter (for example, by means of logging). This leads to drilling crews installing filters at their own discretion, often unsuccessfully. As a result, sharp discrepancies are observed in the yields of neighboring wells drilled by exploration and production organizations. Such examples exist in the areas of the cities of Tomsk and Asino and at other sites.

One of the shortcomings characteristic of prospecting, exploration, and production work for water is the weak study of the microcomponent, microbiological, isotopic, and gas compositions of groundwater, which does not permit the processes of its formation to be studied fully.

Geological organizations of the southeastern part of Western Siberia carry out prospecting hydrogeochemical work insufficiently widely. This is due mainly to shortcomings in the existing instructions for conducting geochemical prospecting. According to the provisions set out in them, hydrogeochemical prospecting is not an independent type of work, but is regarded as incidental sampling, which must be performed by a collector or worker. According to these instruc—

the funds allocated to organizations do not make it possible to employ hydrogeochemical engineers for carrying them out. Meanwhile, hydrogeochemical surveys are an effective, but at the same time complex and responsible type of work, and workers and collectors alone are not capable of carrying them out. The existing situation has led to the fact that production organizations are unable to involve hydrogeochemical engineers in conducting these investigations, which, in turn, does not create the prerequisites for training such specialists in higher educational institutions, although some of them—for example, the Tomsk Polytechnic Institute—have positive experience in this respect.

It should also be noted that, in the course of hydrogeological work, paleohydrogeological investigations are practiced very little, especially in the southern districts of the West Siberian artesian basin and in the territories adjoining it.

In the press and at the 1966 conference on nature protection in Tomsk Oblast, it was pointed out that, up to the present time, many types of mineral waters of the territory have not been clinically evaluated. This, together with the absence of approved reserves of them, is holding back the development of resort construction in Western Siberia.

Materials on the exploration of groundwater and of the waters of mineral deposits in the region under consideration are generalized and published quite insufficiently.

Finally, it should be noted that geological, specialized, scientific organizations and educational institutions are experiencing an acute shortage of hydrogeological engineers. Moreover, in connection with the accelerated economic development of the region, the need for them will constantly grow. It is also necessary to note that production organizations rarely practice the systematic upgrading of the qualifications of hydrogeological engineers and technicians, which, of course, has a negative effect on the quality of the work performed.

Taking into account what has been set out above, tasks in the field of studying and using the groundwater of the southeast of Western Siberia may be formulated.

The principal one among them, in carrying out all types of hydrogeological work, is the study of the process of formation of natural waters and pore solutions, using the necessary number of the newest methods. Special attention must be paid to this question when calculating operational reserves of groundwater, since an assessment of the quantitative and qualitative aspects of the reserves can be competently carried out only under the condition of complete clarity in questions of their formation.

The solution of this task, as of many others, can be ensured only by specialized organizations (expeditions) for groundwater exploration, possessing a sufficient number of qualified hydrogeological specialists and modern equipment. Such organizations, together with scientific research institutions, will be able widely to introduce into the practice of hydrogeological work rapid methods of drilling large-diameter water wells (without clay flushing in sands), as well as investigations for studying the microcomponent, isotopic, microbiological, and gas compositions of waters. Therefore, it is necessary to create them in the territory of the southeast of Western Siberia as soon as possible.

In the near future, the reserves of groundwater should be assessed for use in irrigating arid or periodically poorly moistened districts of Altai Krai, Novosibirsk Oblast, and the southern part of Tomsk Oblast, as well as the reserves of thermal and principal types of mineral waters of the territory (together with their clinical evaluation). An urgent task is ...

the identification of groundwater reserves for domestic and drinking-water purposes in areas of priority industrial development, taking into account their replenishment from surface watercourses.

Groundwater and its regime should be studied in greater detail when developing measures for draining waterlogged territories and peat deposits. Unfortunately, in practice this question receives wholly insufficient attention, which in the final analysis has an adverse effect on the results of land-reclamation works.

It should also be noted that there is now an urgent need to develop technology for the use of the region’s thermal waters in the national economy.

Data obtained in recent years on the ionic-salt, gas, isotopic, organic, microbiological, and microcomponent compositions of groundwater in deep and near-surface horizons show that hydrogeochemical indicators have important significance for oil prospecting and make it possible to carry out both regional and local assessments of prospects. In this connection, great hopes are placed on water-gas and microbiological studies of the first regionally persistent aquifer. The latter will make it possible to trace, within Tomsk Oblast and the Tunguska syneclise, areal gas zonality, manifested in an increase in the content of heavy hydrocarbons from the margins toward the centers of the basins, which on the whole agrees with the oil-and-gas potential of these areas. Against the background of such zonality, oil and gas fields and rupture disturbances are recorded in the form of anomalies.

The rapid development of the oil, chemical, metallurgical, forestry, coal, and other branches of industry and agriculture in Western Siberia has placed on the agenda yet another very important question—the protection of the environment and natural resources, including the protection of groundwater from depletion and pollution.

REFERENCES

1. V. G. Bykov, A. D. Nazarov, N. M. Rasskazov, P. A. Udodov, A. A. Rozin. Map of mineral waters of Tomsk Oblast. In: Materials of the Sixth Conference on Groundwaters of Siberia and the Far East. Irkutsk—Khabarovsk, 1970.

2. V. V. Bykova, P. A. Udodov, N. M. Rasskazov, V. G. Bykov. Mineral waters of the Yugovskaya anomalous zone and their balneological significance. In: Problems of resort climatology, climatotherapy, and the study of mineral waters of Siberia. Tomsk, 1971.

3. Hydrogeology of the USSR, vol. 16. West Siberian Plain. Moscow, “Nedra,” 1970.

4. Hydrochemical Map of the USSR. Map of Mineral Waters. Edited by N. K. Zaitseva and N. I. Tolstikhin, 1964.

5. A. D. Nazarov. Mineral medicinal and industrial waters of Tomsk Oblast. In: Problems of studying resort resources and organizing sanatorium-and-resort treatment in Siberia and the Far East. Issue 2. Tomsk, 1974.

6. N. M. Rasskazov et al. Some hydrogeological and hydrogeochemical features of peat deposits in the central part of the Ob–Irtysh interfluve and certain questions of the methodology of hydrogeochemical studies of bogs. In: Groundwaters of Siberia and the Far East. Moscow, “Nauka,” 1971.

7. A. A. Rozin, P. A. Udodov et al. Map of mineral waters of Tomsk Oblast (1967). In: Study and use of water resources of the USSR, 1966–1967. Moscow, “Nauka,” 1970.

8. P. A. Udodov et al. Hydrogeochemical Investigations of the Kolyvan–Tomsk Folded Zone. Tomsk, Tomsk University Press, 1971.