In well stimulation treatments using hydrochloric acid, undesirable water-in-oil emulsion and acid sludge may produce and then cause operational problems in oil field development. The processes intensify in the presence of Fe(III), which are from the corroded surfaces of field equipment and/or iron-bearing minerals of the oil reservoir. In order to understand the reasons of the stability of acid emulsions, acid emulsions were prepared by mixing crude oil emulsion with 15% hydrochloric acid solutions with and without Fe(III) and then separated into free and upper (water free) and intermediate (with water) layers. It is assumed that the oil phase of the free and upper layers contains the compounds which do not participate in the formation of acid emulsions, and the oil phase of the intermediate layers contains components involved in the formation of oil/acid interface. The composition of the oil phase of each layer of the emulsions was studied. It is found that the asphaltenes with a high content of sulfur, oxygen and metals as well the flocculated material of protonated non-polar oil components are concentrated at the oil/acid interface. In addition to the above, in the presence of Fe(III) the Fe(III)-based complexes with polar groups of asphaltenes are formed at the acid/oil interface, contributing to the formation of armor films which enhance the emulsion stability.

中文翻译：

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酸性油乳液中酸/油界面的组成

在使用盐酸的增产措施中，可能会产生不良的油包水型乳状液和酸性污泥，从而在油田开发中引起运行问题。Fe（III）的存在会加剧该过程，而Fe（III）则来自现场设备腐蚀的表面和/或储油罐中的含铁矿物。为了理解酸性乳化液稳定性的原因，通过将原油乳化液与15％盐酸溶液（含或不含Fe（III））混合，然后将其分离为游离和上层（无水）和中间体（含水）层。假设自由层和上层的油相包含不参与酸性乳液形成的化合物，中间层的油相包含参与油/酸界面形成的成分。研究了乳液的每一层的油相组成。发现具有高硫，氧和金属含量的沥青质以及质子化非极性油组分的絮凝材料都集中在油/酸界面处。除上述以外，在Fe（III）的存在下，在酸/油界面处形成具有沥青质极性基团的基于Fe（III）的配合物，有助于形成增强乳液稳定性的铠装膜。氧和金属以及质子化非极性油组分的絮凝物质都集中在油/酸界面处。除上述以外，在Fe（III）的存在下，在酸/油界面处形成具有沥青质极性基团的基于Fe（III）的配合物，有助于形成增强乳液稳定性的铠装膜。氧和金属以及质子化非极性油组分的絮凝物质都集中在油/酸界面处。除上述以外，在Fe（III）的存在下，在酸/油界面处形成具有沥青质极性基团的基于Fe（III）的配合物，有助于形成增强乳液稳定性的铠装膜。