超低渗油藏原油胶质的防蜡机理与结构特征

Study on Paraffin Inhibiting Mechanism and Structural Characteristics of Resin in Crude Oil of Ultra-Low Permeability Reservoirs

摘要: 高含蜡原油中天然胶质对蜡的沉积具有明显的抑制作用。通过紫外、红外、¹HNMR等波谱学方法并结合元素分析全面研究了长庆超低渗油藏华庆油区伴随井筒结蜡析出胶质的组成与结构，通过X衍射技术研究了蜡晶晶格畸变即胶质的防蜡机理，旨在探讨胶质防蜡作用的结构基础。结果表明，井筒析出纯蜡为C₂₉左右的长链烷烃，析出蜡胶质为含长链烷基、芳基、羰基、酯基等基团的复杂混合物，其中胶质所含长链烷基是胶质与蜡共晶的必要条件。长链烷基所连芳基、羰基、酯基等其他基团则利于胶质在与蜡共晶时致使蜡晶晶格畸变、晶型改变并由长程有序变为短程有序，最终因结构疏松而难以沉积，原油胶质的防蜡作用比较明显。

Abstract: The natural resin of high paraffin crude oil had apparent inhibition for the paraffin deposition. Based on the combination of spectral methods such as ultraviolet, infrared and ¹HNMR analyses and combined with elemental analysis, the composition and structure of paraffin resin from wellbore of Huaqing Wellblock in Changqing Oilfield were studied comprehensively. In addition, X-ray diffraction technique was used to describe paraffin crystal distortion, namely the paraffin inhibition mechanism for the further study of the structural characteristics of resin. The results show that paraffin precipitation from the wellbore is composed of C₂₉ long-chain alkanes and little resin. The resin is from the complicated mixture of paraffin precipitation contained long-chain alkyl, aryl, carbonyl, ester group and so on, in which the long-chain alkyl is the essential condition for the co-crystallization of resin and paraffin, and the rest groups of long-chain alkyl, aryl, carbonyl, ester are helpful for the crystal distortion of paraffin, the change of crystal form and the transformation from long range order to a short-range one in paraffin crystals. The paraffin precipitation is hard to occur due to the loose structure of paraffin crystals. The natural resin of crude oil has significant performance for paraffin inhibition.