【作者】 李广鑫；

【导师】 王武义；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2008， 硕士

【摘要】 在稠油集输过程中,由于管线结蜡严重,导致集输管线输送能力下降,甚至停输,这一现象已成为世界石油工业迫切需要解决的技术难题之一。国内外稠油生产基地集输管线主要以加热加压方式防蜡,每年耗费大量的能源和资金。而磁防蜡降粘技术以其设备安装简单、使用方便、无污染、成本低、能有效提高稠油在集输管道中的流动性的特点越来越广泛地应用于油田。但是,目前对磁防蜡降粘机理认识还不够深入,导致所生产的磁防蜡器通用性不好,致使磁防蜡降粘技术在稠油集输领域没有被广泛应用。针对这一情况,本文找出石蜡沉积的内因,得出主要是由于石蜡结晶后,通过色散力相互作用形成三维网状结构所致;其中,蜡的组成、含量、性质及其在稠油中的形态等是导致稠油流变性质复杂及粘度异常的根本原因。同时,基于核磁共振理论,进行了磁防蜡降粘的机理分析,得出磁防蜡机理是蜡分子按能级规则排列与热运动共同作用的结果。其中分子按能级规则排列,使石蜡分子在结晶过程中间距增大,突破色散力,难以聚集形成三维网状结构,是磁防蜡降粘作用的主要机理。基于磁防蜡降粘机理的分析,研制了具有良好性能的磁防蜡降粘实验系统,其磁感应强度可在0~200mT内调节,并应用有限元仿真软件对其磁感应强度及分布进行仿真分析,磁场强度达到实验要求。采用研制的磁防蜡降粘实验系统对磁防蜡降粘机理进行了实验验证,并分析了蜡含量对稠油粘度的影响规律,及不同含蜡量稠油在磁处理后的降粘规律。结果表明,低温下稠油的粘度受蜡含量影响很大,随着蜡含量的增加,稠油粘度增大迅速;磁处理可以使稠油的粘度降低,各种含蜡量油样经磁处理,其降粘率都随着温度降低不断升高,且低温(粘度值在140~200mP·s范围内)降粘效果比较好,此后降粘率基本稳定;降粘率随磁感应强度增大而升高,在磁感应强度达160~170mT附近时降粘率达到峰值,此后随磁感应强度增大,降粘率基本稳定;磁处理后,稠油冷却过程中析蜡速度加快,释放潜热增多;磁处理使蜡分子规则排列是磁防蜡降粘主要原因。更多还原

【Abstract】 Paraffin-depositing in the pipelines, causing the transportation capacity of the pipelines decline or even shutdown during the transportation of heavy oil, has become one of the most severe problems in the world oil industry. And the oil fields, at home and abroad, guard against paraffin depositing for heavy oil transportation by heating and pressing, have resulted in significant operational costs. Magnetic treatment is now widely applied to guard against paraffin depositing because of its outstanding characteristics, such as the equipments easy to be fixed and operated, non-pollution, low cost, can effectively enhance the fluid of heavy oil in the pipelines. Nevertheless, researchers haven’t understood thoroughly the mechanism of that how magnetism affects paraffin depositing so far, which causes the electromagnetic equipments using for paraffin-controlling aren’t versatile.In view of this situation, this paper finds out that a huge amount of small crystals generated by nucleation stick to each other by the London forces among them and form 3D network is the major internal cause of paraffin deposition. The components, content, and morphology properties of the wax in heavy oil lead to the changes on the rheological properties and viscosity of the heavy oil.The mechanism of paraffin-controlling and viscosity-reducing in heavy oil using magnetic treatment is analyzed, based on the theory of nuclear magnetic resonance, and come to the conclusion the magnetism is attributable to a novel opinion proposed by the authors that the magnetic nucleuses in the paraffin are arranged regularly by the energy level and processing around the direction of magnetic flux density, and the former function, which increases the space among paraffin molecules, reduces the London forces among crystals, and prevents paraffin molecules to form the 3D network during that time of the crystallization, is the main reason for paraffin-controlling and viscosity-reducing.An experimental system with good performances is developed, on the basis of the analysis of the above, whose magnetic flux density can be regulated from 0 to 200mT. And the simulation analysis carried out by the authors to the intensity and distribution of magnetic induction generated by the device using the software of ANSYS, has demonstrated that the performances of which meet the requirements for the experiments.The mechanism of the paraffin-controlling and viscosity-reducing has been proved experimentally using the developed experimental system. Furthermore, the influences of wax content on the viscosity of the heavy oil and the laws of the viscosity-reducing of the heavy oil with different wax content after the magnetic treatment are analyzed by the author. The results show that the viscosity of heavy oil increases with increasing wax content in it, which can be reduced after the magnetic treatment. And the viscosity reduction rates of all kinds of heavy oil with different wax content after magnetic treatment, which are higher when the oil is at the lower temperature (when the viscosity is about 140~200 mP?s ), are rising as the oil’s temperature decreases, and after that temperature they are basically stable with the decreasing temperature; In addition, the higher the magnetic intensity, the more the viscosity decreases, and the viscosity reduction rate reaches the peak value when the magnetic intensity is about 160~170 mT, then it is basic stability or even decreases with increasing intensity of magnetic induction; Besides, the velocity of the crystallization becomes faster after magnetic treatment, which enhances the heat that is released during the time of crystallization. Finally, experiments carried out by the authors have demonstrated that the magnetic nucleuses in the paraffin are arranged regularly by the energy level is the main reason for paraffin-controlling and viscosity-reducing in heavy oil.更多还原