Basin Multi-scale Ecological Impact Of Petroleum Development In Hilly And Gully Loess Regions

Petroleum exploitation is the pillar industry in northern Shaanxi,but petroleum resource exploitation will cause a series of regional ecological and environmental problems,such as land excavation and vegetation destruction.Therefore,it is of great significance to analyze the ecological impact of oil development on regional ecological sustainability.In this paper,the Changwei river basin of the Xingzi river tributary in Yan'an city,Shaanxi province,where oil development is the main industry,is taken as the research area.The oil development activities in this basin are widely distributed and scattered,and it is a typical oil development zone in northern Shaanxi province.Based on the multi-scale analysis of the ecological impact of typical engineering sample plot level,sample plot level and watershed level,this paper gradually discusses the ecological impact of oil development on the research area from the micro to the macro scale.The analysis is as follows:(1)Based on the field vegetation survey,the ecological impact analysis of typical engineering sample size of well site and pipeline shows that different oil development activities have caused different degrees of ecological impact,that is,the ecological impact of well site construction is greater than that of pipeline construction;After well site and pipeline construction,plant species diversity,species richness,community similarity and vegetation coverage of the affected slope around the well site decreased.The plant community structure changed from arbor-shrub-herbaceous or shrubby-herbaceous structure to shrubby-herbaceous and herbaceous structure.The dominant species change,that is,the stable species which is composed of a variety of original local species becomes the pioneer species which is composed of a few species.(2)Based on remote sensing images,the ecological impact analysis on typical sample land scale shows that with the decrease of remote sensing image resolution and the reduction of cartographic scale,the identifiable image resolutions of pipelines,roads and Wells are 1m,10 m and 20 m respectively;The minimum drawing scales of roads and Wells are 1:500 and 1:20,000 respectively;The maximum drawing scale of pipelines,roads and Wells that cannot be made according to the scale is 1:2000,1:20,000 and 1:50,000,respectively.The maximum drawing scale of pipelines,roads and Wells that cannot reflect the ecological impact is 1:10,000,1:50,000 and 1:100,000,respectively.In other words,with the decrease of remote sensing image resolution and the scale-up conversion of cartographic scale,the recognizability and expressibility of the ecological impact of oil development activities gradually decrease.(3)Based on the ecological sensitivity model and ArcGIS 10.2 software,through the analysis of the ecological impact on the watershed scale,it is shown that the research area before oil development is the moderately ecologically sensitive area,which is transformed into the ecologically sensitive area after oil development which is moderately dominated and mildly subpiloted.Can be known from the changes of the vegetation types of the oil development,the study area due to the returning farmland to forest and grass,resulting in a decrease of the area of farmland vegetation,grassland area is increased,so the plant community structure and species diversity in the study area and dominance with the increase of returning farmland to forest and optimization,and also,so the use of remote sensing image of macro Angle in the study area can be identified after the ecological impacts of development for oil is relatively lower before oil development,maintain the ecosystem balance ability,reduced the risk of ecological problems,the overall ecological environment better.(4)Through the analysis of the ecological impacts of oil development on the three scales of sample,sample and watershed,it can be concluded that the ecological impact of oil development and its ecological restoration are most intuitive with small-scale microscopic research;as the scale increases,its ecological impact information loss More and more,the basin scale has been difficult to reflect the ecological impact of oil development,and the current status of petroleum development cannot be reflected in the red line of ecological protection.