Environmental Issue And Information System Construction Of Oil Exploration And Exploitation In The Upper Stream Of Beiluohe River In Northern Shaanxi Province

With large-scale exploitation of oil and gas resources, regional environmental pollution is becoming serious in Northern Shaanxi, one of the most important energy bases of China, where research is relative poor for a long time. So, study on the regional issue caused by energy exploitation is very important. Beiluohe River, Yanhe River and Wudinghe River compose the water system of exploitation area. According to the monitoring data from environmental protection agency of Yan'an City, some water problems, such as deterioration of water quality and water function, water quality-induced water shortage, etc., has been serious since 1980s. Therefore, it is significant to research the regional environmental problems caused by oil exploration and exploitation, which will offer new information for the protection of the water resources of Beiluohe Valley, and improve the regional ecosystem.The study area is located at the upper stream area of Beiluohe River, covering Wuqi County, Zhidan County, and Ganquan County partly or completely. The main work is to investigate the water quality and soil, and construct a database. Water quality was tested by Xi'an Environmental Monitoring Station. Test items include pH, hexavalent chromium, salinity, hardness, and different chemical constituents. Heavy metal content of soil was tested by Xi'an Institute of Geology and Mineral Resources. Combining national standard with the data achieved from testing, the samples of water and soil are analyzed through the method of single factor contaminant index. Then, based on the software platform of Visual Basic 6.0, an information system is constructed using several professional software, such as MapObject, Mapgis, and Arcview, which can be used to achieve various conditions of the study area in the form of data, graph, table.Water quality of Beiluohe River is not good enough even under the natural condition, primarily regarded as "high salinity and high hardness". The main reason is probably that the cretaceous and tertiary strata at groundwater supply district of the upper stream contain more salt, which have strong influence on underground water. Form 1980s to present, water quality of Wuqi and Zhidan has been deteriorated by the oil exploitation. Oil extraction wastewater, ground crude oil, oil sludge and oil contamination are the main pollution source. Due to the fact that the polluted water always contains several times pollutant than normal water, all of which can not be dissolved, the groundwater here is grouped into class-V. Most reaches can not be used to irrigate the crops, which makes the irrigated land change into dry land. Incidence of several diseases caused by pollution becomes higher.According to river bank petroleum contaminated zone and the degree of pollution of the river oil slick, the river valley of Beiluohe River is divided into following four types: 1) Contaminated zone of serious crude oil, 2) Contaminated zone of intermediate crude oil, 3) Contaminated zone of slight crude oil, and 4) no contaminated zone of crude oil. Finally, the opinions and suggestions are put forward to the prevention and cure of oil pollution of this area.