Performance Evaluation Of Surfactant For Fracturing

Based on the tight conglomerate reservoirs in Xinjiang,taking Mahu Oilfield as an example,there are disadvantages such as poor physical properties,low permeability,high formation temperature,and high formation water salinity.After investigation,this paper carried out the effects of temperature and concentration on interfacial tension,emulsification,static oil washing,permeability loss,wettability(contact angle),longterm stability of 3 surfactants and 4 nano-oil flooding agents.The evaluation of properties such as property,dynamic oil washing,etc.,and then screen out surfactants with good performance for oil fields.Experiments show that the oil-water interfacial tension value of surfactant L and Nano No.4 is about 0.1mN/m when the concentration is 0.1%.The ability of surfactant K and several other surfactants to reduce the value of oil-water interfacial tension is average,and the performance of surfactant D to reduce oil-water interfacial tension is the worst;in addition to concentration,salinity also has a greater impact on interfacial tension.Under the salinity,the interfacial tension of the seven agents has rebounded,and the stability of the surfactant K in reducing the oil-water interfacial tension is better than that of the other six agents,followed by Nano No.4 and Nano No.1,between 0.1-1 mN/m.The interfacial tensions of the remaining surfactants were all above 1mN/m;in terms of demulsification,with the increase of surfactants,the demulsification speed slowed down,but the demulsification could be completed after 4hours,and the effect of salinity on demulsification was It has a great influence.Under low salinity,surfactant D has the worst emulsification performance,followed by surfactant L.Other agents have demulsification for 12 hours,and the demulsification rate is above 80%.Under high salinity,all agents have demulsification for 4 hours.The demulsification rate reached 100%;in terms of wettability,at 0.1% concentration,the contact angle of L and Nano No.2 was smaller,and at high concentration of 0.5%,surfactant L had the smallest contact angle and better lipophilicity.surfactant and Nano No.1 have larger contact angles so its lipophilicity poor;in terms of long-term stability,the interfacial tension of the seven oil displacement agents increases first and then decreases with the increase of time,but the order of magnitude remains unchanged.The long-term stability of the oil displacement agent is good;the permeability damage of the seven surfactants to the core is very weak,less than 11.1%;the dynamic oil displacement experiment shows that the oil displacement efficiency of Nano No.4 oil displacement agent is the highest,reaching 7% Above;surfactant Khas the highest oil displacement efficiency among the surfactants;among them,Nano.4 has been put into use in Ma131 block.