盆地异常低压系统处置油田污水可行性

松辽盆地十屋断陷区油气分布复杂,勘探程度高,油田外排污水规模巨大,常规技术处理污水效果不理想。区内4 km以下部分地层呈负压态,若容储介质参数达到相应地质填埋标准,则可在工程实践中尝试应用。结合该区水文及地质资料,建立地下水流及污水污染物迁移数值模拟模型,模拟研究区低压系统入注污水时地下水流动特征及污染物的迁移规律,同时估算了系统空间污水容储量。在预测过程中,分析了断陷区负压形成机制及分布特点,同时结合虚拟粒子示踪及注水过程,对污水的环境影响度进行了预测。研究结果表明,十屋断陷异常低压区是一个天然污水封闭储藏区,系统地层压力梯度仅为0.005~0.008 MPa/m,容储量高达1.241×10⁸ m³,且污染物逃逸概率极小,非常适合油田污水的处置。

Feasibility of Oilfield Wastewater Disposal in the Underpressure System of Basin

The distribution of oil and gas in Shiwu depression of Songliao basin is complex,the prospecting degree is high,and the conventional technology for huge scale oilfield wastewater treatment is not ideal.Four thousand meters below of the strata in the study region is pressure negative,we can apply it for storage of the oilfield wastewater in engineering if the storage medium parameters are suitable in terms of the corresponding geological landfill conditions.Based on the hydrological and geological conditions of Shiwu depression in Songliao basin, the groundwater flow and pollutant transport model are constructed to predict storage ability and describe space distribution features of the underpressure area under the condition of infusing wastewater. The formation mechanism and characteristic of distribution of underpressure are analyzed in calculating process,and the environmental effect of wastewater is predicted based on the simulating virtual particle tracer and injection process. This research shows that the underpressure system of Shiwu depression is a natural closed storage reservoir with capacity up to 1.241 × 108 m3 ,which is suitable for wastewater injection and storage. The system pressure gradient is 0.005 0.008 MPa/m,and the pollutants are less likely to escape.