含蜡原油流动性与磁处理条件间机理关系及其量化表征

Recent years, with the wide application of magnetic treatment technology in the oil fields, increasing amounts of problems exist, such as the crude oil viscosity rises or remains the same after magnetic treatment, the main reason is that the influence of magnetic treatment on wax molecule motion and wax crystal aggregation is not clearly ensured, and the relationship between waxy crude oil flow property and magnetic treatment condition is not mastered. Through theory analysis, molecular dynamics simulation and experimental study, this project discusses the mechanism of paraffin controlling and viscosity reducing with magnetic treatment from multi-scale and multi-dimension. Molecular dynamics method is a method for simulating the interactions between waxy molecules in a magnetic field. Static magnetic treatment experiment is adopted for measuring crystal parameters and thermodynamic parameters，with reference to the molecular dynamics simulation results，the mechanism relationship between crude oil flow property and magnetic treatment condition is analyzed. Dynamic magnetic treatment experiment is employed for studying the key factor that influence the magnetic treatment results, considering the waxy oil composition and flow condition, further exploring the mathematical model that describe the quantitative relationship between waxy crude oil flow property and magnetic treatment condition. The project is expected for revealing the mechanism of paraffin controlling and viscosity reducing with magnetic treatment, breaking through the bottleneck that restrict the theoretical development of waxy crude oil with magnetic treatment, laying scientific foundation for further magnetic study.

近些年来，在含蜡原油磁防蜡降黏实施过程中，磁处理失效或者出现负效应的现象时有发生，其根本原因是没有明确磁场对原油中蜡分子运动以及蜡晶颗粒聚集状态的影响效应，也没有掌握含蜡原油流动性随磁场条件变化的规律。本项目拟通过理论分析、分子动力学模拟与磁处理实验研究，从多尺度和多维度探索含蜡原油磁防蜡降黏机理。采用分子动力学方法研究磁场对蜡分子间相互作用的影响，通过静态磁处理实验测试磁处理前后热力学参数和结晶参数的变化，结合分子动力学模拟探索含蜡原油流动性与磁处理条件间的机理关系，通过动态磁处理实验确定影响磁处理效果的关键因素，考虑原油组成和管流条件，建立定量表征含蜡原油流动性与磁处理条件间关系的数学模型。预期该研究将揭示含蜡原油磁处理机理，突破制约含蜡原油磁处理发展的理论瓶颈，为含蜡原油磁处理技术奠定科学基础。

近些年来，在含蜡原油磁防蜡降黏实施过程中，磁处理失效或者出现负效应的现象时有发生，其根本原因是没有明确磁场对原油中蜡分子运动以及蜡晶颗粒聚集状态的影响效应，也没有掌握含蜡原油流动性随磁场条件变化的规律。针对含蜡原油开展磁处理实验研究，发现在磁场作用下沥青质颗粒尺寸减小和蜡晶尺寸增大是降黏的主要原因。采用灰色关联理论，计算了降黏率与磁处理条件、原油组成和测试条件间的灰色一般关联度，确定了影响磁场降黏效果的各个因素的主次顺序。通过正交试验探究了磁处理时间、磁处理温度、磁场强度和流速对降黏率的影响效应，确定了最佳的动态磁处理条件。分子动力学模拟结果进一步证实了磁场对含蜡原油的降黏效果。通过分析蜡的径向分布函数和沥青质的构型，发现磁场促使了蜡分子的聚集和沥青质团簇的分散，该结果与磁处理实验的显微观察结果一致。通过对比磁处理前后正壬烷、环庚烷、甲苯和蜡分子的扩散系数，发现磁场使分子受到的空间位阻作用减小，迁移性增强，扩散系数增大，从而实现降低黏度的效果。预期该研究将揭示含蜡原油磁处理机理，突破制约含蜡原油磁处理发展的理论瓶颈，为含蜡原油磁处理技术奠定科学基础。