Evaluation of Ultra Low Concentration Surfactant System for Chemical Flooding
Evaluation of Ultra Low Concentration Surfactant System for Chemical Flooding
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DOI：
10.3997/2214-4609.201601837
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发表时间：
2016-08
期刊：
影响因子：
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通讯作者：
I. Sagbana;P. Diaz;M. Centeno
中科院分区：
文献类型：
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作者：
I. Sagbana;P. Diaz;M. Centeno
为了选择一种用于化学驱的表面活性剂配方，必须在油藏条件下对表面活性剂进行评估，以确定其与待注入油藏的相容性。这是为了避免在油藏中形成凝胶和沉淀，因为这可能导致表面活性剂提高采收率的措施不成功。在一些研究中，表面活性剂仅在含有氯化钠盐的盐水中于室温下在实验室进行了测试。然而在油田实际情况中，温度更高，而且油藏盐水含有二价离子。在这项研究中，对在硬盐水和中等原油中含或不含助表面活性剂的极低浓度醇烷氧基硫酸盐进行了评估。在60°C下进行的盐度扫描、相态和岩心驱替实验结果表明，醇烷氧基硫酸盐对二价离子具有耐受性，并且通过添加甲酯磺酸盐和内烯烃磺酸盐作为助表面活性剂可以提高其稳定性。这些助表面活性剂能够降低微乳液相的粘度，通过提高增溶比产生更低的界面张力，并且还能使原油采收率至少提高20%。
In order to select a surfactant formulation for chemical flooding, the surfactant has to be evaluated at reservoir conditions to determine its compatibility with the reservoir to be injected in. This is to avoid formation of gels and precipitation in the reservoir which can make surfactant enhanced oil recovery unsuccessful. In several studies, surfactants have been tested in the laboratory at room temperature using only sodium chloride salt in the brine. While in oilfield scenario, the temperature is higher and the reservoir brine contains divalent ions. In this study, very low concentration alcohol alkoxy sulfate with and without a co-surfactant in hard brine and medium crude oil has been evaluated. The results from the salinity scan, phase behaviour and core flooding experiments at 60°C shows that alcohol alkoxy sulfate is tolerant to divalent ions and its stability can be improved with the addition of methyl ester sulfonate and internal olefin sulfonate as co-surfactants. These co-surfactants were able to reduce the viscosity of microemulsion phase, create a lower interfacial tension by increasing solubilisation ratio and also increase oil recovery by at least 20%.