Spotlight on Environmental Impact of Energy Development 45
Figure 2: Location of wind turbines and producing oil and gas wells.
(86.30 km) and the electricity substations. Based on average width, we buffered the access roads to 11m and the transmission lines to 6.096 m. Combined, the overall disturbance of the wind project was 488 ha, or 1.23 ha per turbine pad.
Study Area: Orenburg region
Russian Oil and Gas (O&G) key test landscapes are located in Orenburg region and contain three oil fields (figure 5). Development began here in 1994, leading to a considerable bulk of accumulated anthropogenic load which promotes significant transformation of natural complexes. Over 100 areas with oil–producing infrastructure objects are located in this research territory with about 4.75 wells per/100 km². These objects are representative of the various types of O&G steppe landscapes.
Fieldwork in Orenburg region has also been conducted. Many oil and gas production objects (inside wellpads) were visited and we defined key characteristics including: size, shape, amount of land disturbed, variety, as well the spatial distribution of these elements in each wellpad. Initial results show spatial variation according to the type of drilling activity, location and age of operations.
A list of indicators for estimating the geoecological state of oil extraction landscapes was made.
They take into account specific features of natural steppe zone conditions such as: semiarid continental climate, few areas of water; and oil field functioning features such as: the number of infrastructure objects in each wellpad, environmental pollution linked to hydrocarbon production, and the use considerable amounts of fresh water.
At the moment a rating scale is being developed, where each indicator will be assigned a specific point corresponding to its contribution to anthropogenic transformation. Currently we estimate two indicators:
(1) Natural acceptability of landscapes for the location of oil and gas objects (represented as points);
(2) Areas of dense vegetation cover to absorb carbon oxide (carbon sinks).
The Natural acceptability of landscapes for the location of oil and gas objects involves these parameters:
- (1) Slope of relief. Slope affects erosion and ravines, which begin to develop intensively after the slope value is more than 3º;
- (2) Aspect of elevation. Aspect is the one of the basic contributors to erosion: ceteris paribus, the band of soil removed by erosion is considerably wider on the southern, south-western and south-eastern sides than on Northern side;
- (3) The distance between the oil fields objects and water objects. The further away from water sources, such as rivers and streams, is important as the migration of chemical and mechanical components into water bodies through agglomeration of oil field objects is possible. Water sample analysis taken from the river within the oil field at the Russian key test plot showed excess maximum permissible concentration (MPC) amounts of hydrocarbons for water basins at 5.5 times (MPC = 0.3 mg/l). Oil and gas objects located within 500 m of a water basin were found to create a higher risk for water contamination.
The natural suitability of landscapes for oil and gas production was calculated based on a SRTM digital elevation model by combining three parameters above. Also we used layers of oil point objects and water objects for our key test plots. Evaluation of each parameter will be realised by a method of expert
Figure 5: The Russian key plot selected for study is located in the Orenburg region (basemap source: ESRI). Figure 4: The footprint of wind development in the study area. Red indicates turbine pads, while blue represents access roads and transmission lines.
assessment of parameter’s significance as part of total score for general assessment of a landscapes’ geoecological state. The conversion of exposure rasters, slope, remoteness and summing of their scaled values (25, 25 and 50%) were made using ArcGIS 10.2 Spatial Analyst tools. The final image was classified into three categories with equal intervals, and landscape acceptability results were shown (see figure 6).
We then counted the oil and gas objects located inside red, yellow and green zones. Next we assigned scores following
ecological comparisons of different oil and gas landscapes. We used the method of expert estimations and assigned the scores shown in Table 1:
Table 1: Scoring of parameters of natural acceptability of landscapes Density is <
Red zone
Yellow zone Green zone
0.25objects /1 km2 3
1 0
Density is 0.25-0.5 objects
/1 km2 4
2 1
Density is >
0.5objects / 1 km2 5
3 2
Figure 3: Oil and gas disturbance in the study area. The blue lines indicate oil access roads, while red represents wellpad disturbance.
www.envirotech-online.com IET January / February 2016
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