Campen Sophie Margaret, Moorhouse Saul J, Wong Janet S S
Department of Mechanical Engineering , Imperial College London , London , U.K. SW7 2AZ.
BP Exploration Operating Company Limited , Chertsey Road , Sunbury-on-Thames , Middlesex , U.K. TW16 7LN.
Langmuir. 2019 Sep 17;35(37):11995-12008. doi: 10.1021/acs.langmuir.9b01792. Epub 2019 Sep 6.
Surface deposition of destabilized colloidal particles of asphaltenes poses a serious and costly problem during petroleum production. Remediation of asphaltene-fouled well bore and surface facilities is often undertaken by flowing aromatic solvent to remove deposited films. However, little is known about the properties of deposited asphaltene films during their removal by solvent rinsing. Here, we carry out quartz crystal microbalance with dissipation monitoring (QCM-D) experiments to investigate surface deposition of destabilized colloidal particles of asphaltenes and their subsequent removal by solvent rinsing. It is shown that the properties of deposited films during solvent removal depend on the history of the deposit. Newly formed deposit films are removed immediately without significant change in their mechanical properties during removal. However, deposits that remain on the surface for an extended time in a poor solvent (a low asphaltene solubility solvent), "aged deposits", are more difficult to remove and exhibit increased dissipation during the removal period, indicating that they swell and are softer. Liquid-cell atomic force microscopy (AFM) confirms that aged deposits swell when the quality of the solvent is subsequently improved by exchanging for a high asphaltene solubility solvent. Deposit swelling is accompanied by a change in film morphology, from particulate to continuous. Stubborn deposits of aged asphaltene films, which remain after solvent rinsing, may be partly removed by flowing dissolved asphaltenes in good solvent. Hence, reinjection of asphaltenes during remediation can aid deposit removal.
在石油生产过程中，沥青质胶体颗粒失稳后的表面沉积会带来严重且成本高昂的问题。通常通过注入芳烃溶剂以去除沉积膜来修复被沥青质污染的井筒和地面设施。然而，对于溶剂冲洗去除沉积沥青质膜过程中的膜性质却知之甚少。在此，我们开展了带耗散监测的石英晶体微天平（QCM-D）实验，以研究失稳的沥青质胶体颗粒的表面沉积及其随后通过溶剂冲洗的去除过程。结果表明，溶剂去除过程中沉积膜的性质取决于沉积物的形成历史。新形成的沉积膜在去除时能立即被去除，且去除过程中其机械性能无显著变化。然而，在不良溶剂（低沥青质溶解度溶剂）中长时间留在表面的沉积物，即“老化沉积物”，更难去除，且在去除过程中耗散增加，这表明它们会膨胀且更软。液池原子力显微镜（AFM）证实，当通过更换为高沥青质溶解度溶剂来改善溶剂质量时，老化沉积物会膨胀。沉积物膨胀伴随着膜形态的变化，从颗粒状变为连续状。溶剂冲洗后残留的顽固老化沥青质膜沉积物，可通过在良溶剂中流动溶解的沥青质来部分去除。因此，修复过程中重新注入沥青质有助于沉积物的去除。
