Researchment On Crude Oil Emulsion Efficient Demulsification Technology Related Mechanism And Characteristics

The exploitation of margial oilfield, deepwater oilfield and green oilfield brought about new challenge to oil & gas gathering and transferring process. It was necessary that the corresponding treatment apparatus should be more efficient and compact, In responsed to the above requirements, not only need innovation of related crude oil electric dehydration technology and equipment, the drop micro electrostatic coalescence mechanism during the process of crude oil electric dehydration also needs to be perfected. Based on crude oilemulation, the theory and practice of effective demulsification technology using power frequency and high frequency electric field in both mesoscopic scale and microscopic scale was researched in this thesis.On a mesocopic scale, this paper studied how waveform effect electrostatic coalescence process in the static condition by means of cylindrical electrostatic coalescing device, experimental result showed that under the conditions of consistent emulsion characteristics and remaining field parameters, different waveforms sequence in accordance with demulsification was: AC square wave? AC sine wave? AC triangle wave ? pulsed DC. A set of small crude oil electrostatic coalescing rapid test and evaluate device was built, on the basis of the above work, Liuhua 11-1 oil field aging oil’s dehydration properties under flow conditions was measured, the result showed that high frequency /high voltage electric field dehydration rate reach up to 97.8%, superior than industrial frequency/high voltage electric field which dehydration rate was 4.2%.On a microscopic scale, with the help of combined “near-infrared camera + microscope”, a single water droplet in crude oil emulsion crushing mechanism under different physical and electric parameters is observed. Experimental results show that in industry-frequency electric field the droplet is broken mainly by electric force excessive stretch, and the maximum diameter ratio can reach 2.54 when the drop begins instability. High frequency electric field increases the droplet instability of interfacial film and then the drop distorts, deformation and broken. During this process the maximum diameter ratio less than the industry frequency electric field. Two droplets or droplet colonies are taken as research object, the central distance and travel speed in aggregation process with different field intensities, frequencies and drop diameters. The results show that the field frequency mainly effects the immediate process of droplets aggregation. The field intensity enhances travel speed during aggregation process. However, after a certain degree the high intensity field would scatter and distribute the droplets which situation causes the increasingly stability of emulsion. Similarly, the diameter of droplets have positive correlation to the aggregation efficiency, but droplets with large size tend to be unstable since the boundaries become vulnerable under high frequency or high intensity electrical field.The results of this paper enrich the research content of electrostatic coalescence demulsification of W/O emulsion. The work reveals how the high frequency /high voltage alternating other electric field and it’s advantages from the deep mechanism angle. It provide the technical basis for new technologies as VIEC technology and high voltage/high frequency pulsed AC electric field in crude oil dehydration field, and lay a soild foundation for simplification of oil& gas gathering and transferring process.