Stabilization Mechanism Of Polymer Flooding Wastewater And Water Purifying Mechanism Of Compound SCL-1

With polymer flooding applied to enhance oil recovery and increase oil production in many oilfields, large amount of wastewater, which is much more difficult to treat than that from water flooding, has been produced. The produced water from polymer flooding contains a quantity of residual hydrolyzed polyacrylamide (HPAM), which seriously impedes the oil-water separation. The present wastewater treatment process in the oilfield fails to treat the wastewater from polymer flooding properly within usual settling time. As a result, the effluent can not reach the reinjection standards of oilfield, and serious environment pollution would also be created if the wastewater was discharged to land surface. The wastewater treatment has become a bottleneck for the application of polymer flooding; therefore it has high application value and environment benefits to develop effective treat and recycle technologies for the wastewater produced in polymer flooding.At present, Shengli oilfield was adopted compound SCL-1 in Gudao, and it showed good effect in oil-water separation and demulsify of wastewater treatment process in polymer injection area. It has no negative influence on the viscosity when using the treated water to confect polyacrylamide solution. But the main agent of SCL-1 should be imported. It is hard to cosmically using because of high cost. On the other hand, the water purifying mechanism is ambiguity, and may be not suit for other polymer injection area or new agent development. Therefore, the research on water purifying mechanism of SCL-1 is very important for the development of wastewater treatment agent of polymer flooding produced fluidsIn this thesis, I made a systematic research on the stabilization mechanism of polymer flooding wastewater and water purifying mechanism of compound SCL-1, which regards wastewater treatment that produced by polymer flooding. It aims to give some effective measures and suggestions to solve wastewater treatment. The details are as follows:1. The simulation of water, oil and emulsion were prepared according to the actual molecular weight distribution of HPAM in wastewater and the formation conditions of oil-water emulsion. Then I made a research on the stability and mechanism of oil-water emulsion that influence by HPAM through analyzing the oil content in water, dehydration ratio in oil, Zeta potential and particle size distribution of oil droplets.The result shows that because HPAM has a long molecular chain and good scalability and flexibility, it is able to strengthen the dilational viscoelasticity of interfacial film when the HPAM was absorbed on it. As a result, it is more difficult to break the interface during the collision of two oil droplets, so that it can reduce the collision efficiency of oil droplets. In addition, HPAM can increase the electrostatic repulsion force among oil droplets, and the collision and coalescence probability will be reduced consequently. In the early stage of oil-water emulsion formation, the coalescence of oil droplet will be influenced by the above two factors. Then the particle size will also be lessening. Finally, low floating velocity may cause separation of oil and water difficultly.2. The discussion on wastewater treatment agent SCL-1 shows that it can solve the inhabitation of polymer and enhance the oil growth in order to get high oil removal ratio. Comparing with the agent that we commonly use, this agent has different water purifying mechanism during flocculation progress. By mixing ROMAX-668 and HF-03, it can increase floc growth speed and its size.