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Главная FEDERAL MONITORING OF GEOLOGICAL ENVIRONMENT OF THE WEST-ARKTIC SHELF - THE STATE, OBJECTS AND PROSPECTS OF DEVELOPMENT
FEDERAL MONITORING OF GEOLOGICAL ENVIRONMENT OF THE WEST-ARKTIC SHELF - THE STATE, OBJECTS AND PROSPECTS OF DEVELOPMENT Печать E-mail

KORNEEV O.JU., RYBALKO А.Е., FEDOROVA N.К.
State Company “Sevmorgeo”, Russia

Federal monitoring of the geological environment of a shelf is a subsystem of the State ecological monitoring of an environment of water areas. The estimation of a status of bowels, including the characteristic of underground waters and their interactions with superficial waters, and also geochemistry of a contact zone "bottom-water" are the main tasks of the monitoring. The special problem is the estimation of the morpho-lithodynamic processes in a coastal zone, and also an estimation of danger of endogenic processes for exploitation of engineering constructions in the sea. The perspective areas on oil-and-gas, a transport infrastructure are the basic objects of monitoring on the West-Arctic shelf . It includes numerous places of an overload of mineral oil (stationary and floating terminals), and also ways of its transportation, both a land, and on the sea.

Now only preparation for development of the first on the Barents shelf of a oil field - «Prirazlomnoe» is conducted. However, the near beginning of these works, and also escalating intensity of transportations of petrohydrocarbons demands continuation of the control over a status of an environment of water areas. The important problem is also the choice of the parameters measured in natural waters and bottom sediments which allow not only to estimate the common condition of an environment, but also really to allocate in this estimation the contribution of the anthropogenous factor.

Monitoring of the geological environment of bowels of the West-Arctic shelf, directed on an estimation of long-term processes, is the major component of the common ecological monitoring. The representatives of the companies should be carried out this monitoring within the limits of license sites, according to the law. A aim of federal monitoring in these conditions are regional study of the Barents Sea with a choice of key polygons, an estimation of existing geological dangers and the regional forecast (estimation) of consequences of such activity. The concrete tasks of the State monitoring on the West-Arctic shelf are:

1. An estimation of background characteristics of chemical elements in bottom sediments and a near-bottom water, in areas intensive recently sedimentation;
2. The characteristic of geodynamic processes on a shelf and their influence on concrete formation of geochemical structure of bottom sediments and a near-bottom waters, and also exchange processes on geochemical frontier"bottom-water";
3. The control of activity of geodynamic processes and their changes at the beginning of development of Oil-And-Gas Deposits.

Reorganization of system of federal monitoring has begun in 2005 and actively proceeded during 2006-2007. The observations of monitoring on federal network which spatially were within the limits of license areas "Varandey-Sea" and «Prirazlomnoe» have been stopped during this period. Accordingly, the new network of stations in Novaja Zemlja Trough, the open part of the Barents Sea and along northern extremity of Kola Peninsula has been organized.

For the period of three-year monitoring in Novaja Zemlja Trough it has been established, those abnormal high concentrations of heavy metals and arsenic in near-bottom waters often are fixed. The most contrast anomalies are characterised for zinc and copper. Their distribution is and unstable in time. The connection these anomalies to coast of Novaja Zemlja is distinctly looked. Contents of zinc reach 6-16 CLP (critical level of pollution), and copper - 5-6 CLP. The highest concentration of lead (up to 6-7 CLP) also is fixed in a coastal part of Novaja Zemlja. Thus the highest concentrations of these microelements have been established in 2005. In 2007 they have essentially decreased. The analysis of geophysical materials has shown that the part of these anomalies is connected with continuation of tectonic faults from a land where they supervise polymetallic deposits with Cu-Zn specialization. On the other hand, it is a zone of modern tectonic activization. It has allowed to make a conclusion, that water exchange on system of tectonic fractures between underground and superficial waters can serve one of factors of formation of geochemical structure of near-bottom waters.

Earlier we had been established the similar fact at studying iron-manganous nodules in the Gulf of Finland. proves to be true also The results of studying of bottom sediments confirm the given conclusion. The contents of Ni, Co, V, Pb and Cr are below a level of background, Сu and Аs are at a level or above background at all stations executed in 2007. Concentration Cu is changed from 30 up to 106 ppm, at background value 89 ppm. Thus the maximal values (> 100 ppm) are connected with thin pelitic deposits, i.e. distribution of these microelements is controlled by lithological factors. All the increased contents, as well as in near-bottom waters, are precisely localized near the western coast of Novaja Zemlja. Though the level of these concentrations is low, the increase of concentration of heavy metals in superficial lamina of fluid mud of modern deposits can speak about a source which settles down on a modern land.

The increased contents of Pb in near-bottom waters have been revealed and in a southern part of the Pechora Sea, but they it is essential below and exceed CLP a little and are more stable in time. In our opinion formation of these anomalies can be connected with a drain from coast where there is an active development of seaside parts of oil-and-gas deposits, and active abrasion of a coastal zone has threatened safety of technogenic objects near to a coastal line.

As have shown supervision in the open part of the Barents Sea in 2006 - 2007, here stations with the high contents of heavy metals are periodically fixed. So, in the western part of the Barents Sea high concentration have been revealed (mkg/l): cadmium - 29.64, lead - 20.36, zinc-81.55 and copper-28.59. Exceeding of CLP on all parameters is 10-30 times. The increased contents of zinc and copper have been established and at other stations. In area of Shtokman deposit in 2006 very high concentration of lead (153.04 mkg/l) has been established. These abnormal values are not connected in any way with bottom sediments where concentrations of heavy metals usually are at a level of a geochemical background. Probably, a source of abnormal concentration of heavy metals is Nordcup current bringing pollution of the western sources. The accumulation of metals is promoted by the lowered dynamic activity of near-bottom water. The occurrence of similar local anomalies in near-bottom waters of the Murmansk through, in particular arsenic indirectly testifies about it. So, influence of inflow the Atlantic waters is felt even in Kola bay. However, in our opinion, the short duration and localness of similar anomalies is connected and with other natural source - an inflow of fluids from bedrock on systems of tectonic fractures.

The modern seismoacoustic researches executed «Sevmorgeo» by carrying-out of regional seismic profiles have shown, that these fractures penetrate thickness of Holocene deposits through. It demands essential trying to understand at standard interpretation of data of geochemical monitoring the top part of a section of bottom deposits, especially in conditions of development of the enterprises of an oil-and-gas complex. On the one hand, occurrence of high concentration can be not connected in any way with consequences of work of chisel platforms. On the other hand, extraction of oil-and-gas resources in conditions of wide development of disjunctive disturbances can make active outputs of underground fluids and fixing of it by methods of monitoring. The finding of precise criteria of difference of actually technogenic and natural anomalies with use of modern analytical methods is an essential problem which should be solved in the near future.

All told about heavy metals is really to the main pollutants of marine basins directly connected with an oil-and-gas complex - to petrohydrocarbons (HC).

Thus it is known, that in the Pechora Sea many anomalies HC are connected from them infiltration or emissions from bottom sediments. The marine shipping and an infrastructure serving it concern to number of real sources of technogenic pollution. Data of monitoring of 2006-2007 confirm this conclusion. On the overwhelming majority of stations excess of CLP is not fixed, and the contents of mineral oil varies from 0.01 up to 0.04 mg/l. In 2006 The small excess of a control level (0,05 mg/l) has been fixed along line of shipping at island Vaigach. The increased values also have been revealed in area of Shtokman deposit that was interpreted from the point of view of high permeability of quaternary cover. The lowest concentration HC in a near-bottom waters have been fixed along Kola peninsula where outputs of underground fluids practically are not known. But also here it is distinctly shown connection concerning the increased concentration of HC to a mouth of Kola bay. It is possible to tell responsibly, that now practically there is no even a weak pollution of hydrocarbons of bottom sediments. Their contents oscillate from 0.006 up to 0.013 mg/g.

However, long-term influence of a transport infrastructure can be looked after on an example of Kola bay, and also of some little gulfs of northern coast of Kola peninsula where there is a basing navy fleet. Here pollution as water thickness and, especially, bottom deposits is distinctly shown. For example, concentration HC in bottom sediments of port ladles of Murmansk can reach up to 25-30 mg/g, that at 25-30 times more a level of intensive pollution. Thus polluted there are sandy deposits, and the highest concentration HC is fixed at contact of superficial sand and underlying limnoglacial clays.

Concentration of Sr in bottom sediments near the apatite terminal in Murmansk trading port in 17 times exceeds background concentration for the Barents Sea. In the same place concentration of copper and the zinc, connected with transportation and storage of copper-nickel ores are very high. In near-bottom waters conditions are quieter, that is connected with accepted measures on sewage treatment in city and dumps of water weights from vessels. The basic problem is places of basing of the Navy where proceeds not authorized discharge of the polluted waters. The doubtless problem is floating reloading petroterminals which also are the increased object of risk.

Prospects and problems of federal monitoring of the geological environment are connected with inclusion in a complex of supervision the control for endogenic processes. Thus represent importance as actually endogenic and endogenic-caused exogenic processes (landslips, a scrip). The analysis of position of the revealed oil-and-gas deposits shows, that the majority of them is connected with fault structures. The significant part of these faults has the continuation and in the top part of a sedimentary cover, including a tire cover of the quaternary deposits. Presence of modern geodynamic processes in immediate proximity from deposits, certainly, is potentially dangerous, and, accordingly, should enter into a complex of problems of federal monitoring of the geological environment. Thus it is necessary to have in view of, that extracting of NC from underground tanks stimulates a dangerous geological processes to which number it is possible to carry a subsidence of quaternary sediments. So, the quantity and intensity of earthquakes have sharply increased in Northern sea in process of working of heavy metals The similar picture according to the American experts was observed and in Texas ((USA).

Resulted above data show, that the control over modern geodynamic processes should become a necessary element in the geoecological safety of an oil-extracting complex on Barents-Kara shelf. The perspectives federal monitoring are connected with use of the bottom stations allowing simultaneously to track endogenic and exogenic processes and to register the dangerous processes in on-line regime with transfer of the information through the satellite channel in the center of decision-making. In state company «Sevmorgeo» the project of geoecological station with modules has been developed:

• gravitational-seismical for a prediction of earthquakes,
• electrometric for definition of pollution of near-bottom waters,
• sedimentological consisting from sedimentological traps with 12 glasses for maintenance of annual gathering of suspensions,
• the channel of a satellite communication.

The station is constructed on trochlear principle and allows to use it for the various tasks. Installation of such stations should be spent in a zone of crossing of faults, in the center sedimentary basins, and also near to controllable objects. Most part these objects settle down on a sea-bottom, in a zone of the federal property. The information received by helps of these stations should accumulate in the regional center and then be transferred in the Federal center «Geoecology of Russia». Organizational work consists in constant presence of the vessel, ready to leave to the bottom stations, submitted a signal and to provide procedural works on it.

So, the state monitoring of the geological environment on the West-Arctic shelf takes the place, problems{tasks} and objects and is the major part in maintenance of ecological safety of extraction of petrohydrocarbonic raw material, that, in turn, is the major in a number of maintenance of economic safety of Russia. Its development should occur in close connect with local monitoring on license sites and in contact to other subsystems of Federal ecological monitoring, including monitoring of hydrobionts. In this case it is possible to estimate really ecological consequences of development of oil-and-gas branch on the Arctic shelves. And it, in turn, in many respects is determined by structural transformations in Ministry of Natural Recourses of the Russian Federation.

OIL AND GAS OF ARCTIC SHELF 2008

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