Marine ecosystems of Aniva Bay and offshore area of the north-eastern Sakhalin are characterized by rich biodiversity combined with high ecological sensitivity. These water areas are important for fishing and belong to the highest fishery category. More than 100 species of valuable commercial fish (including salmon, herring, cod, flounder) and invertebrates (several species of crabs, shrimps, gastropods) live here. These waters are also important habitats for rare and protected species of birds and marine mammals.
Human induced impact on these ecosystems can affect the condition of biological resources of the sea. Therefore, ensuring environmental safety, protection and preservation of vulnerable marine environment and biota is a priority for Sakhalin Energy during offshore activities in Sakhalin.
Potential environmental risks are caused by a combination of difficult natural and climatic conditions where offshore fields development takes place, ecological vulnerability of northern ecosystems and presence of valuable commercial and rare species of marine aquatic organisms.
These factors require timely assessment and management of environmental risks in implementation of the Company production activities. To prevent and minimize negative environmental impact, a regular environmental monitoring is carried out in accordance with the environmental legislation of the Russian Federation as well as international and corporate standards which include advanced international practices and technologies.
Environmental monitoring of the water areas within the license areas of oil and gas fields and Prigorodnoye port is carried out by Sakhalin Energy during operation of the offshore production facilities. The monitoring is carried out in order to timely identify potential impact of the Company production activities on environment, to forecast development of processes affecting the quality of sea water, bottom sediments and condition of biological communities as well as for decision-making including development of corrective measures to manage environmental impact.
The industrial environmental monitoring program in the area of potential impact of offshore production facilities is carried out in accordance with the permits of the environmental authorities of the Russian Federation and the Company Environmental Action Plan.
The monitoring covers study of the condition and interannual variability of the parameters of marine environment and biota at the following facilities:
– PA-A, PA-B, LUN-A platforms;
– Underground facilities for disposal of drilling waste at Piltun-Astokhskoye and Lunskoye oil and gas fields;
– Prigorodnoye asset (LNG/OET, TLU), Aniva Bay.
The monitoring program covers study of hydrological indicators, hydrochemical parameters, presence of pollutants in the seawater and physical and chemical composition of bottom sediments as well as monitoring of plankton communities and benthos. These data allow to asses condition of marine environment and anthropogenic impact.
Since 2018, field survey in the location of oil and gas fields has been carried out from the board of a modern supply vessel Gennady Nevelskoy. Monitoring of marine environment in the Prigorodnoye port (Aniva Bay) is carried out from the Company tugs which allowed to ensure reliable operations and to optimize scope of work.
Assessment of the spatial and temporal variability of environmental parameters completed on the basis of the analysis of long-term monitoring data versus the baseline values and established standards allows us to make the following conclusions:
– Hydrochemical indicators and pollutants (petroleum hydrocarbons, heavy metals, phenols, detergents) in the seawater in the area of offshore production facilities comply with the standards established for water bodies of fishery importance (MPC) and are in the range of baseline values for The content of chemical substances (total petroleum hydrocarbons, poly-aromatic and aliphatic hydrocarbons (n-alkanes), phenols, detergents) in bottom sediments is unevenly distributed which is associated with a mosaic distribution of various types of soils and regional geological specifics.
– The content of pollutants in bottom sediments in the location of platforms and offshore facilities of the Prigorodnoye asset is within the baseline values typical for these water areas and below the concentrations that cause primary biological effects at the level of organisms and communities of marine ecosystems.
– Concentrations of total petroleum hydrocarbons in the bottom layer of water and bottom sediments in the location of underground disposal facilities for drilling waste at Astokhskoye, Piltun and Lunskoye areas do not exceed the MPC and are below the baseline values typical for this area.
– Petroleum hydrocarbons and methane are not accumulated near suspended appraisal well heads at the Piltun-Astokhskoye and Lunskoye fields.
– Benthic communities in the location of platforms and within the boundaries of the fields are typical for the north-eastern waters of Sakhalin and are characterized by a rich species diversity with high quantitative indicators comparable to the baseline values. Identified communities are characterized by variability of the species composition depending on the sea depth and types of bottom sediments. The structure of communities in the location of platforms is stable, no tendency towards a decrease in biomass and number of organisms has been revealed.
– The dominance of pollution-sensitive species in benthic communities indicates favourable environmental conditions in the location of platforms. No tendencies for a decrease in the indices of species richness and abundance were revealed in the location of fields. Distribution of pollution indicator species in the area of potential impact of offshore facilities at Prigorodnoye asset also does not reveal any anthropogenic impact from the production activities of the Company.
The results of many years of research indicate the stability of indicators of local marine ecosystems in the location of Sakhalin Energy offshore production facilities during the operation phase. Compliance with the standards and baseline values confirms the lack of impact of the production facilities on the quality of sea water, bottom sediments and condition of marine biota in the waters of Piltun-Astokhskoye and Lunskoye fields of the north-eastern offshore area of Sakhalin and Prigorodnoye asset in Aniva Bay.