Research On The Treatment Of Oilfield Produced Water By Integrated Equipment

Considerable oily sewage is produced during oil&gas exploitation and development phase, such as produced water in multipurpose Station, backwater from flushing fluid, and discharge water out of well-drilling so on. In the meanwhile, substantial water is produced from oil wells at later stage of oilfield development, therefore, formation pressure depletes. In view of pressure-up keeping, plenty of water will be injected into wellbore. Water produced out of oil&gas wells is disposed and then is reinjected into production wells. On the one hand, formation pressure will be upkept, production rates is maintained. The other hand, the quality of sewage discharge will decline. There exists the balance between productions and injections. It is of vital industrial and environmental consequence. As for the oilfield produced water disposal and reinjection into oil wells, it is not only of vitally social consequence, but also of gigantically economic consequence.The source, dangerous effects and sort of the oilfield produced water are summarized in this paper. Various traditional approaches to treat oilfield produce water are discussed in detail. On the base of this, "coagulation& precipitation —coalescence—fine filtration" comprehensive processing equipment has been brought forward. At present, coalescers is used in about 50% of apparatus used to remove oil from oilfield produced water. There are many types of coalesecers, but the surfaces of coalescers are homogeneous. It is difficult to achieve the same high efficiency in removing oil from different wastewater. Based on number of tests, some substance which with inhomogeneous surfaces are selected to prepare coalescers, and satisfactory results have been obtained. Filtration treatment relevant technologies on oilfield produced water are investigated in this paper. Filtering procedures mechanism is developed. Filtering procedure of the unit, the thickness of filter medium layer and filter material regeneration process are investigated in-house experiments. These results will provide certain basis for treatment equipment design, simultaneously can provide optimizing configuration between device structure and working parameters.Under the laboratory situation, we obtain the oily wastewater with high densityfrom the Petrochemical business enterprise in Wuhan, and the oil factory in Jianghan oilfield to do experiments. Pilot test shows that the removal efficiency of oil, and suspended solids reached 98.1%, and 95.5%. Moreover, from the experiments, we select the oil-proof ceramics material D2 as coalescent material. By coagulation experiments, the dosage of flocculants and pH value have been optimized. The oil-adhere ceramics material C7 have been selected as filtration material, thickness of filter medium layer and diameter of material have been optimized, which are favorite for the optimal operation.Finally, the benefit of the comprehensive treatment equipment is evaluated. Experiments show that this equipment has high social, economic and environmental values.