Study On Ecological Restoration Technology Of Oil Field Well Site

In view of the analysis and remediation of oil-contaminated soil in Shengli Oilfield(Dongying)of Sinopec,the study on ecological technology of oilfield well site is carried out.Based on the analysis of soil pollution in normal production well pads and decommissioned sealed well pads of Shengli Oilfield,the variation law of petroleum hydrocarbon,organic matter and catalase content in well pad soil with production and decommissioning years and the range of petroleum hydrocarbon content and p H value in well pad are obtained.Through the determination of petroleum hydrocarbons in the soil at different depths of the well site and at different distances from the wellhead,the distribution law of petroleum hydrocarbons in the soil of the well site is found out and the soil quality is evaluated.The concentration range of petroleum hydrocarbons in ecological remediation experiments is determined by the content of petroleum hydrocarbons in well site soil.Among them,the natural degradation experiment of petroleum hydrocarbon is designed as the control experiment of ecological restoration experiment,the single factor experiment of watering amount,adding bulking agent and adding compound fertilizer is designed as the artificial stimulation experiment,and the response surface is used to optimize the single factor artificial stimulation experiment and obtain the best experimental scheme of artificial stimulation.The artificial stimulation-plant combined remediation experiment was designed.Through screening20 kinds of plant seeds suitable for growth in Dongying area,plants with high tolerance to petroleum hydrocarbons were obtained.The best artificial stimulation scheme was combined with plants with high tolerance.The artificial stimulation-plant combined degradation experiment of petroleum hydrocarbons in contaminated soil in well site was designed,and the degradation rate of petroleum hydrocarbons in soil under the optimal ecological remediation scheme was obtained.By measuring the number of bacteria in the soil,the remediation mechanism of the combined remediation system for petroleum contaminated soil was explored.The results show that the petroleum hydrocarbon content and organic matter content in the soil gradually increase and the catalase content in the soil gradually decreases with the increase of production years in the continuous production well pad.For the well pad that is decommissioned and sealed,with the increase of decommissioned and sealed years,the content of petroleum hydrocarbon and organic matter in the soil gradually decreases,and the content of catalase in the soil gradually increases.The range of petroleum hydrocarbon content and p H value in the soil of normal production and decommissioning well sites are 0 mg/kg-613 mg/kg and 6.78-8.39 respectively,while the range of petroleum hydrocarbon content in the soil of accident well sites is 1151 mg/kg-8882 mg/kg.The content of petroleum hydrocarbon in the soil of normal production and decommissioned well sites decreases with the increase of soil depth,and gradually decreases with the increase of distance from wellhead.The degradation rate of petroleum hydrocarbons in the oil-contaminated soil after 70 days of degradation experiment is only 4.8%without C、N and P regulation,while the degradation rate of petroleum hydrocarbons in the oil-contaminated soil after70 days of C、N and P regulation is 9.1%.After 70 d artificial stimulation experiment,the degradation rate of petroleum hydrocarbons in soil under the optimal artificial stimulation condition is 28.6%.Through the screening of 20 plants,peanut has the highest tolerance to petroleum hydrocarbons in soil,and the degradation rate of petroleum hydrocarbons in 70 d soil reaches 31.1%.After 70 days of peanut-artificial stimulation,the degradation rate of petroleum hydrocarbons in soil reached 38.9%.By measuring the number of bacteria in the soil of the combined remediation system,the number of bacteria in the soil at this time is 6×10~9.