Autumn 1994 (2.3)
Hydrobiological Survey of the
Chirag Oilfield Area
by Dr. Liz Ireland
Unique Study Conducted
Although seasonal research surveys have been conducted throughout the Caspian, there have been few attempts to analyze the results in a way that would treat the whole sea as an indivisible ecosystem. Nor did any of these surveys incorporate Chirag oil field where British Petroleum and Statoil Alliance (which now head the Western Oil Consortium) were negotiating exploration rights.
This survey conducted in 1992 was not intended to be a comprehensive Environmental Impact Assessment, but only to provide an initial understanding of the existing environmental conditions.
BP has won various environmental awards including the prestigious WEC (World Environment Centre) Gold Medal for International Corporate Environmental Achievement in 1988 for a project in Wytch Farm, Europe's largest onshore oilfield. In 1992 they were awarded UK's first prize from the Royal Society of Arts Better Environment Award for Industry.
Caspian as Ancient Lake
The Caspian is the largest water basin in the world isolated from the World Oceans. Its average water volume is 80,000 km3 and its maximum depth is 1025 meters.1
The north Caspian is considerably shallower than the mid and southern regions and for this reason it has a considerably different environment. The Caspian basin (the area within which the Sea is located) has been subject to great fluctuations in tectonic movement and inundation of water. During the Pleistocene Era, great amounts of water flooded into the Caspian caused by the melting of the ice cap at the end of each glacial period. At the time of the last flooding, approximately 10,000 years ago, the water level was estimated to be 78m higher than the present day levels. At that time, the Azov Sea and the Black Sea were both connected to the Caspian.2
Marine Life in the Caspian
Prior to this increase in sea level the Caspian benthos (bottom living animals and plants) were mainly comprised of genuine Caspian species. The connection to the Azov Sea enabled the movement of Azov and Black Sea benthos into the Caspian. The Volga-Don Canal (opened in 1952) has also considerably changed the benthos which is currently represented by 724 species and sub-species of bottom-dwelling animals. Of these, 16 species originated from the Azov and Black Seas.3
Types of Pollution
Pollution of the Caspian is a serious issue and one that was raised during the Soviet regime.4 Untreated wastes and pollution from industrial and oil field activities have been reported in a number of journals and reports. In 1985 the Water Conservancy Directorate of the Southern Caspian Republics of Azerbaijan, Dagestan, Turkmenistan and Kazakhstan calculated that industrialists had dumped 10,200 tonnes of oil products and 104,200 tonnes of sewage into the Sea.5 According to the State Committee of Nature Protection in Azerbaijan, the intensification of offshore oil and gas exploration and production in the Azerbaijan sector of the Caspian has resulted in severe contamination of the marine environment, due to non-compliance with ecological regulations.6
Mud Volcanoes in the Caspian
There are also a number of natural seepages of oil occurring on the seabed from mud volcanoes which are major geomorphologic and bathymetric features generated by periodic expulsion of mixtures of water, oil, gas and solids.7 Azerbaijan is believed to be the most active area in the world for mud volcanoes.8 The huge petroleum resources offshore Azerbaijan are intimately associated with mud volcanoes, and although they provide profound insight into the nature of physical and geochemical processes deep within the sediments, they also contribute to the levels of oil found in the seabed and Caspian waters
Hydrobiological Survey of Chirag
An environmental definition of the Chirag oil field area was undertaken on behalf of the BP and Statoil Alliance by two British environmental companies, the Field Studies Council and M-Scan (biological and chemical environmental experts respectively), together with the Azerbaijan State Committee for Hydrometeorology. The project involved marine sampling and sample analysis and was designed to encourage the exchange of technology and environmental experience between British and Azerbaijani scientists. Four scientists from the State Committee of Hydrometeorology laboratories visited Britain for two weeks to exchange information and receive training in techniques commonly used in Britain for marine surveys.
Survey Made at 24 Points
In 1992, we took samples at 20 points identified in a regular grid over the Chirag oil field area (See diagram). An additional four points, reasonably close to known exploration well sites, were also sampled to determine if impact from previous exploration drilling could be detected in the sample analyses.Caspian-More Polluted than Reported
The average concentration of petroleum hydrocarbons (oil products) in the Caspian Sea is reported to be 0.0046 milligrams per liter (mg l-1), which is several times the maximum permissible pollutant limit established by the USSR.9 The mean of the total hydrocarbons in the surface waters sampled over the Chirag oil field analyzed by gas chromatography is 0.06 mg l-1, which is several times higher than the levels previously reported for the Caspian.
The results also suggest that there is a degree of petrogenic (crude oil) and phenol (refined oil product) contamination of the surface waters. It is suggested that pollution from both existing offshore oil field activities and the effluent discharges from chemical works and oil refineries on the Absheron Peninsula are the most obvious sources of the hydrocarbons. However, it is not known to what extent the natural oil seepages contribute to these levels as this was outside the scope of this study.
The mean concentration of chloride and sodium is about four times less than for open ocean water. However, the value obtained for sulfate is greater than that obtained for open ocean water.
Hydrocarbons were detected in the sediments with elevated levels being generally associated with the deeper sampling points. The hydrocarbons appeared to be well biodegraded and weathered which reflects a chronic input, probably of crude oil and it is reasonable to assume that these arise from natural seepages and mud volcanoes that are known to exist within the Chirag oil field area.
There was no detectable disturbance within the sediment composition that could have been attributed to the dumping of drill cuttings from the exploration wells, although there were elevated concentrations of barium at these sites which is probably associated with drilling fluids.
The majority of the bottom dwelling marine fauna were found in the shallower water sampling sites, where the sediments are composed mainly of gravels and shell fragments. In the deeper sampling sites the sediments are composed of muds and fine silts and virtually no benthos were detected.
It is known that there are lower numbers of species in the Caspian compared with the Black Sea although the environmental conditions or ecological niches are much the same. From Karpinsky's work10 it would appear that although there are a limited number of species at depth, this is not necessarily an indication that the environment is contaminated to such an extent that nothing will live in it.
Karpinsky suggests that these niches may simply never have been occupied. Indeed the polycheates Neris succinea, N. diversicolor and the bivalve mollusk Abra ovata were introduced into the Caspian to inhabit the vast areas of available soft substrate in order to provide a food source for sturgeon. The fact that these were introduced successfully without displacing any other organism would seem to suggest that they occupied a hitherto vacant ecological niche.
The data provided by this initial survey has provided valuable insight into the environmental conditions of the Chirag oil field area and also given an opportunity for Azerbaijan and British scientists to exchange methodologies. The information, however, yields only a limited understanding of the overall Caspian ecological system.
For example, no attempts were made to analyze fish movements or the microfauna. A thorough environmental survey to establish a "baseline" of existing environmental conditions would be necessary prior to carrying out any oil field activities offshore Azerbaijan. Such a survey would form the basis of the comprehensive Environmental Impact Assessment which is required under the regulations of the State Committee of the Azerbaijan Republic on Nature Protection.
(For more details about how the study was attempted and for the tables of concentrations of pollutants found in this survey, contact the author at BP Exploration, 4-5 Long Walk, Stockley Park, Uxbridge, Middlesex UB11 1BP, England. Tel: 081-750-6326 Fax: 081-750-0276.)
Liz Ireland is Senior Environmental Scientist, BP and Statoil Alliance in the UK.
1 Jafarov, F.M. ed. 1992. Review of the Environmental Conditions Associated with the Chirag Oilfield. Report to BP and Statoil Alliance.
2 Walter, H. and E.O. Box. 1983. Caspian Lowland Biome in Temperate Deserts and Semi-Deserts, Vol. 5. Ecosystems of the World. N. E. Elsevier West, ed. ISBN 0-444-41931-4.
3 Kasymov, A.G. 1982. The Role of Azov-Black Sea Invaders in the Productivity of the Caspian Sea Benthos. International Revue. ges. Hydrobiology. 67:533-541.
4 Rich, V. 1972. Problems of the Caspian. Marine Pollution Bulletin. 3:84-85.
5 Anon. 1988. The Lingering Death of the Caspian. New Scientist.
6 Jafarov. op cit.
7 Karpinsky, M. G. 1992. Aspects of the Caspian Sea Benthic Ecosystems. Marine Pollution Bulletin. 24:384-389.
8 Hovland, M. and A.G. Judd. 1988. In Seabed Pockmarks, p. 190. Graham and Trotman ISBN 0 86010 948 8.
9 Khoroshko, V. I. et al. 1989. Ecologotoxicologial Situation in the Eastern Part of the North Caspian Sea in Sturgeon Fishery in USSR Water Bodies. Abstracts of papers, Part 1, pp 331-332. Astrakhan (in Russian).
10 Karpinsky. op. cit.
Other Valuable Sources:
Kuliyev, B.B. et. al. 1993. Analysis and Evaluation of Damages of Azerbaijan Offshore Industrial Objects Caused by Extreme Hydrological Processes of the Caspian Sea in Proceedings of the Second Baku International Symposium, Energy, Ecology and Economy. Gunesh: Baku.
Mansurov, A.E. ed. 1993. State Report: Environmental Conditions and Nature Protecting Activities in Azerbaijan Republic. ISBN 5-8240-0031-x.
Rich, V. 1982. Caspian Water Level Drops. Nature. 299: 384.
From Azerbaijan International (2.3) Autumn 1994.
© Azerbaijan International 1994. All rights reserved.