The Research On Different Porous Media's Impact Of Oil And Water Separation Efficiency

At present, most of the oilfields have entered the middle and late age of oil development, the amount of water, which is injected into the reservoir, needs to be increased year after year, so the reconery water will also be increased. A large number of oily wastewater produced by the oil-water separation, if discharged directly without treatment, will cause environmental pollution, and bring threat to people's lives in a serious situation. Using the coarse-grained method to treat the oil wastewater for the first level, can reduce the oil content significantly, and then the secondary and advanced treatment will make the various indicators of oil reach the requirements of injection water in the low permeability.The key technology of the coarse-grained method that is used to remove oily wastewater is selection of coarse-grained material. The indoor experiments of the oil-water separation are studied in this paper, using five filters: walnut shell, ceramic, polyethylene, sand, oil-sands, and for the material: walnut shell, oil-sands, which are better on the separation, we did lipohhilic-hydrophilic experiments, and for the walnut shell, ceramic, oil-sands, we did the coarse-grained experiments in the field, and we theoretically analyzed the floating rate of the small paricles in the porces of porous meida, concluding the floating rate of wastewater in the porous media and the thickness of the porous meida that effect the oil-water separation, and the function of coarse-grained material for the walnut shell, ceramic, oil-sands, is also included.Laboratory results show that, with the increasing of the water flow rate, the separation efficiency of different porous media's impact of oil-water is lower; with the increase of the thickness of porous media, the separation efficiency is increaseing, when the thickness reaching a certain value, the separation efficiency will be 100%. Walnut shell, oil-sands are lipophilic media, but the hydrophobicity of the oil sands is stronger than walnut shells.The scene coarse-grained experiments show that, the growth in the propotion of the oil- sand, making the oil droplets size of the sewage is the largest, about 3 times; while the coarse -grained role of walnut shell and ceramic is poorer, abuot 2 times; the three filter's impact of the smallest 10% droplets is little, the growth in the propotion is 1.2 times more or less, which means the effect is not obvious.When the porosity of porous media is larger, the small particles will take a long time to up to the wall, which is not conducive to separation. Through adding gas or oil into the oil-sand, we found that the the coarse-grained role of oil-sand that is added into gas is worst, oil drople-ts at the outlet is bigger than the inlet diameter, only 1.3 times in value; oil-sand that is added into oil can make oil droplet size increase by 2.3 times; oil-sand that is added into oil and gas can make oil droplet size increase by 2.8 times.