玛北页岩油强乳化作用机制及室内破乳实验

Mechanisms of Strong Emulsification and Laboratory Demulsification Experiments for Mabei Shale Oil

摘要

新疆油田玛北页岩油采出液具有高矿化度、高乳化稳定性等特性, 在热化学沉降与电脱水工艺中存在破乳温度高、脱水效率低、脱水能耗高、电脱水操作不稳定等一系列问题。鉴于此, 以玛北页岩油采出液为研究对象, 基于分子动力学模拟与室内耦合脱水工艺实验, 揭示了其强乳化稳定作用机制及高效破乳方法。分子动力学模拟结果表明, 胶质、沥青质与硅化合物、高矿化度盐类在油水界面通过氢键与极性相互作用形成高机械强度的刚性界面膜, 显著阻碍液滴聚并, 是导致采出液高度稳定的本质原因。在此基础上开展了旋流-电脱耦合工艺的室内验证实验, 该耦合工艺能充分利用旋流场的预破乳效应, 结果表明：70 ℃、破乳剂浓度200 mg/L条件下, 经旋流预处理及电化学脱水后, 采出液含水率降至0.1%以下, 达到深度脱水要求。该研究为玛北页岩油的低耗高效脱水技术提供了理论依据和工艺参考。

Abstract

The produced fluids from the Mabei shale oil reservoir of the Xinjiang oilfield is characterized by high salinity and strong emulsion stability, leading to a series of challenges in thermal-chemical sedimentation and electrical dehydration processes, such as high demulsification temperature, low dehydration efficiency, high energy consumption, and unstable operations of electrical dehydration. Accordingly, this study focuses on the produced fluids from the Mabei shale oil reservoir and performs molecular dynamics simulations and laboratory-scale hydrocyclone-electrostatic coupled dehydration experiments to elucidate the mechanisms underlying their high emulsion stability and to explore effective demulsification methods. Molecular dynamics simulation results indicate that resins, asphaltenes, silicon compounds, and high-salinity salts form a rigid interfacial film at the oil-water interface through hydrogen bonding and polar interactions. This film, exhibiting high mechanical strength and significantly hindering droplet coalescence, is fundamental driver for the high stability of produced fluids. Based on these findings, laboratory experiments integrating hydrocyclone pretreatment with electrochemical dehydration are conducted. This coupling process can fully utilize the pre-demulsification effect of the swirling flow field. The results demonstrate that at 70 ℃ and a demulsifier concentration of 200 mg/L, the water content in the produced fluid is reduced to below 0.1% after hydrocyclone pretreatment and electrochemical dehydration, meeting the requirements for deep dehydration. This study provides a theoretical foundation and technical reference for the development of low-energy-consumption, high-efficiency dehydration technologies for Mabei shale oil.

关键词

页岩油 / 破乳 / 油水分离 / 旋流分离 / 电脱水

Key words

shale oil / demulsification / oil-water separation / cyclone separation / electrostatic dehydration

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基金资助

中国石油天然气股份有限公司新疆油田分公司科研项目“玛北页岩油先导试验区采出液乳化机理研究与高效破乳剂筛选”(XJYT-2025-JS-6161)