Research On Evaluation And Inlfuencing Factors Of Specific Vulnerability Of Oilfield Groundwater System

The pollution problems of oil component to soil and groundwater exit in severaloil fields in our country, which could be detrimental to the health of human beings,animals and plants and even cause destruction to social economy, ecosystem structureand function. However, the research of evaluation model to vulnerability assessmentof groundwater system in oil field is not too much currently and it is very important toprotect the environment of soil and groundwater in oilfield development. Consideringthe hydrogeologic conditions and main oil pollutant properties in typical oilfields ofChina, a new model named DORKI was proposed for oilfield groundwater specificvulnerability assessment based on the widely used DRASTIC model. The Zhongyuanoilfield vulnerability was evaluated though analysis the regional characteristics of thestudy area. Specific vulnerability to BTEX was also evaluated in typical area of theZhongyuan Oilfield based on the oilfield groundwater specific vulnerabilityassessment model—DORKI. Finally, considering the effect of additive to oilcomponent migration in oil exploitation, the influence of the anion surface activeagent sodium dodecyl benzene sulfonate (SDBS) to toluene adsorption of Zhongyuanoilfield soil was studied by laboratory experiment. The main conclusion was obtainedas follows:1. The application to evaluate the groundwater situation in an oilfield districtshows that the DORKI model can reasonably reflect the effect of the various factorsin evaluation, so that the pollution risk of oil component to groundwater could beevaluated exactly.2. The DRSI model was built based on the regional characteristics of Zhongyuanoilfield. And then the intrinsic vulnerability and concentration variation range ofsulphate and TDS of shallow groundwater was analyzed using ArcView GIS software.In addition, the sulfate and TDS concentration change of Zhongyuan oilfield shallowgroundwater were analyzed through the ArcView GIS space analysis function. In thetotal research area, the southern area exhibited high vulnerability and this areaaccounted for61.66%. The northern area exhibited low vulnerability and this area accounted for22.42%. The area with ordinary vulnerability accounted for15.92%and this area located in Qinghetou-Liutun area of old channel sedimentary of theYellow river. The Huzhuang-Xuzhen area and the north of Wenliu-Huzhuang area hadhigh TDS concentration and formed “bitter water area” with various extent. Thespecific vulnerability to BTEX of shallow groundwater in typical area was highertotally. This research provides countermeasures for the shallow groundwaterprotection of Zhongyuan Oilfield. In addition, the integrated use of "natural" and"special" can be used as a new shallow groundwater vulnerability assessment modelin oilfield area.3. The additives in oil exploitation may influence the adsorption of oil to oilcomponent and cause the mobility change of oil component. The laboratoryexperiment showed that the adsorption of experimental soil to SDBS was notpositively correlated with organic matter content of oil. In the range of experimentalconcentration, SDBS had a solubilization effect to toluene.