The Research And Application Of Wastewater Treatment Technology In Feng Ping Oil-gathering Station

At present, most domestic oilfields are in mid-late stage of production, and the average water percentage of produced fluid was 70～80%, even achieved 90%. Most formation water was produced and brought much waste water the produced fluid was demulsified and deoiled. The oilfield wastewater from Feng Ping oil-gathering station was 1000m3/d, with the characteristic of high oil, suspended solids (SS) concentration, high corrosion rate and numerous bacteria et. al. If the wastewater was discharged without any treatment, it could contaminate the soil and water source; even cause fire accident in oilfields, which would threaten people’s safety and cause economic losses. Conversely, the wastewater could be reinjected to enhance oil recovery if it was treated before discharged, it would not only meet the growing requirements of water injection during oilfield exploitation but also save water source, reduce the environment pollution, maintain and increase the reservoir pressure, it was helpful for the development of the oilfields and getting a stable and high yield for oil production.Water injection is a inportant way to increase oil recovery and efficiency. The treated water about sewage is the key to achieving efficient development of oil fields. A large number of oil-produced sewage is separated by the oil and water. It is a complex system containing suspended substance, oil and dissolved inorganic salts, dissolved gas and dissolved organic matter.then it has the nature of that:harmful to oil reservoir, corrosion to oil-production equipment and pipe line of oil and water transported, scaling in surface pipeline and reservoir.In order to guarantee the oil field produced wasterwater of Feng Ping oil-gathering station reaches the recommended quality standards for reinjection water, and solve the oil content, suspend solids, sulfide, bacterial content, serious corrosion and scale buildup problems of the treated produced wasterwater by former process. A chemical oxidation/flocculating setting treatment process were examined and the optimized produced wasterwater treatment parameters for reinjection were determined, in terms of pH value, sulfur elimination, flocculant, as well as coagulantthe. The experimental results show that:when pH value, dosage of sulfur elimination, PAC and PAM(molar mass:12 million) are 7.5,15 mg/L,80 mg/L and 1.0 mg/L respectively, and agent adding order is PAC before PAM, interval time of agent addition is 20～30s were used as the parameters for processing oilfield produced wasterwater, the suspended solids content, the oil content average corrosion rate, amount of scale buildup, bacterial content of the treated water wese down to 0.5 mg/L,0.54 mg/L 0.036 mm/a,2.6 mg/L, and 10cfu respectively.These parameters indicate that the quality of the treated water could meets the recommended quality standards for reinjection by the process we adopted.