Surfactant Surfactant System Optimization Study

Oil is an important non renewable strategic resource.Most of the oilfields in China have entered the late stage of oilfield development.The oil produced by waterflooding has the characteristics of high water cut,which greatly reduces the economic benefits of oilfield development.It is an urgent work to strengthen oil recovery economically and efficiently.Chemical flooding has played a great role in improving oil recovery efficiency in the late stage of oilfield development.Surfactant flooding in chemical flooding is the most promising technology in the tertiary oil recovery.The working principle of surfactant is to improve oil recovery by reducing the interfacial tension between oil and water,changing the wettability of rocks rate.There are many researches on the performance of surfactants abroad,and many industries are very mature.However,in China,surfactant flooding started late,but also achieved good results.At the same time,it is also faced with difficulties in the research and development of new surfactants.It is difficult for a single surfactant to achieve the effect of oil field flooding to reduce the interfacial tension between oil and water.Therefore,it is necessary to apply surfactant especially composite performance of surfactants were studied.Based on the basic geological data of tian2 block,this paper analyzes the reservoir characteristics,reservoir fluid properties and field production status of the well,carries out the basic experiments of core porosity,permeability and two-phase seepage curve of the well,obtains the field reservoir geological data of the area,and carries out field experiments with single and multiple compounded surfactants.The results show that the optimum 0.2%HABS-1+0.1%APG+1%Na2CO3 has good stability,high temperature and salt resistance.Under certain conditions,the system can keep the interfacial tension at a very low level for a long time.Even if 0.2%HABSloses 40%and 0.1%APG 25%,the system can still maintain the ultra-low interfacial tension.During the water injection period,the average water injection amount is 0.36pv in the anhydrous period,36.01%in the dry period,1.39pv in the water injection period,45.01%in the water injection period;the amount of cool surfactant has a great impact on the replacement rate.When the injection volume reaches 0.4pv?0.5PV,the improvement of displacement efficiency becomes smaller and smaller,the oil volume is no longer increased,and the oil displacement efficiency of surfactant is maximized.At different injection time,the effect of injecting surfactant to displace bottom hole reservoir is not obvious.However,the method of injecting surfactant first and then water flooding is better than water flooding until the water content is close to 100%,and then the displacement effect of surfactant flooding is betterBased on the basic data of well Tian 2 area,a large number of experiments on surfactant performance have been carried out in this study,and the oil displacement effect of surfactant has been evaluated and analyzed.The results obtained are of certain significance to the improvement of recovery rate of remaining oil in Jingdong oilfield.