| ASP flooding is one of the key EOR technologies which are researched andapplied in Daqing oilfield. However, ASP’s commercial popularization has beenconfined due to some problems occurred during the application,such asinjection-production system scaling by injecting high concentration alkali, shortsupply of qulified surfactant in the current market as for large surfactant volume isneed during the application. Therefore, exploring new-type ASP system to reduceusage of surfactant and alkali is one of the effective ways to solve above problems.Byrecognization of biosurfactant classification and applied technologies of currentbiosurfactant used in ASP flooding, and aiming at solving the above problems, thispaper focuses on the following subjects:(1)A ASP formula has been confirmed to achieve the goal of reducing oil-waterinterfacial tension of the target reservoir by screening and obtaining the biosurfactantsample which has synergistic effect with the chemical surfactant.(2)Viscosity, stability of oil-water interfacial tension, influences of waste waterto activity of the ASP system with biosurfactant under the reservoir temperature havebeen analyzed in the lab and the ASP system has been optimized.Through analysis, a quasi ASP composite system with biosurfactant has beendeveloped, comparing with the ASP systen used in the field(NaOH1.0%～1.2%,alkylbenzene surfactants0.15%～0.2%),it can get ultra low interfacial tensionwith the tested crude oil under NaOH0.5%～0.8%, alkylbenzene surfactant0.05%～0.15%. In addition, it can meet the need of field application when the usage of NaOHis reduced by20%and alkylbenzene surfactant by20%as well. Meanwhile, stabilitiesof viscosity and interfacial tension of the biosurfactant ASP system are superior tothose of the chemical ASP system and the oil displacing results are the same.The research result provides the feasible technique and formula for further popularization of ASP composite system in the field and it will accelerate theapplication of the technique. |
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