胶质氧化程度调控对致密油乳状液界面活性的影响规律

Effect of Resin Oxidation Regulation on the Interfacial Activity of Tight Oil Emulsion

致密油采出液乳化稳定性强,导致下一步破乳处理等成本较高。以吉木萨尔致密油为研究对象,通过分析致密油组分组成,探究胶质含量及其氧化程度调控对采出液界面稳定性的影响规律。结果表明,吉木萨尔致密油中的胶质含量为16.83%、沥青质含量仅为0.3%,胶质含量高可能是致密油乳状液稳定的主要原因之一。对胶质进行氧化处理后,胶质中的氧含量增加,并产生部分含有—COOH的物质,使得胶质界面活性升高,不利于破乳的进行。当以0.4%H_(2)O_(2)对胶质的氧化程度进行调控时,可提高胶质芳香度,降低其极性,使得致密油与水的接触角变小,界面张力变大,进而降低致密油乳状液的储能模量和损耗模量,降低界面膜强度,有助于其破乳。在80℃下,先以0.4%H_(2)O_(2)溶液轻度氧化预处理30 min,再用现场用破乳剂破乳,可使致密油乳状液脱水率由65.0%增至82.2%,对现场致密油采出液高效破乳提供了理论支持。

Tight oil has high cost of demulsification due to its strong emulsifying stability.Taking Jimusar tight oil as the research object,the effects of different resin content and oxidation degree on the interface stability of produced liquid were explored by analyzing the composition of tight oil.The results showed that the content of resin in Jimusar tight oil was 16.83%,while that of asphaltene was only 0.3%.The high content of resin might be one main reason for the stability of tight oil emulsion.After the oxidation of resin,the oxygen content in resin increased for the production of partial carboxyl substances,which increased the interface activity of the resin and thus was not conducive to demulsification.When the oxidation of resin was regulated by 0.4% H_(2)O_(2) solution,the aromaticity increased while the polarity decreased.As a result,the contact angle between tight oil and water decreased,while the interfacial tension increased.Furthermore,the storage modulus and loss modulus of tight oil emulsion and the interfacial membrane strength decreased,which was beneficial to the demulsification.At the temperature of 80℃,the demulsification rate of tight oil emulsion was increased from 65.0%to 82.2%by using demulsifier after the oxidation pretreatment 30 min with 0.4% H_(2)O_(2) solution,which provided theoretical support for the efficient demulsification of produced liquid in tight oil on site.