High Temperature And High Salinity Reservoirs Of Surfactant / Polymer Binary Complex Flooding Study

Alkali/surfactant/polymer flooding, which cooperates with alkali, surfactant and polymer, can enhance oil recovery greatly. But there are some questions during the practical use of ASP. Among them the most severe effect is that alkali can lower formation permeability because it can disperse formation clay and make them traveling, the same time, alkali makes spot technique complicated and forms alkali scale in the well bottom to reduce the production, shortens cycle of checking pump. And there will be alkali scale in the reservoir of high temperature and salinity. So it's very necessary to study of surfactant/polymer flooding without alkaline. Analyzed from theory, the high recovery should have been obtained in Surfactant/polymer flooding because of the capability of the polymer, which can better control the fluid mobility to extend the sweeping volume, and the surfactant, which can reduce the interfacial tension between oil and water to enhance the micro-efficiency of displacement. But there are many problems must be solved if the surfactant/polymer flooding is applied in the high temperature (98℃) and high salinity (ion concentration of Ca~2+, Mg~2+ is higher than 500mg/L) reservoir, including how to select surfactant and polymer, how to realize the function of ASP by using surfactant/polymer system and whether the surfactant/polymer flooding can be used practically.Considering above problems, a series of jobs have been done. First, author analyses the objection of selection standard, and results of driving tests in the condition of high temperature and salinity prove that only if interfacial tension reaches 10~-2mN/m or the least value dynamic interfacial tension reaches 10~-3mN/m, the system can enhance oil recovery. Basis on it, author simply estimates and selects two chemical systems from the compounds of eleven kinds of surfactants and four kinds of polymers, then the interfacial tension, viscidity, salinity requirement diagram, ability of cutting, stabilization and static adsorption of the different surfactant/polymer systems are studied and compared, and finally a chemical system: 0.25%MJ2+1500mg/L hydrophobic association polymer AP-P5 which adapts to zhongyuan hushi'er oilfield is found. Driving tests prove that the system is effective and the result of phase behavior shows why surfactant/polymer system can enhance oil recovery, and then injection plugs are optimized by using numerical simulation technology, and result of forecast proves such system can enhance recovery more 19.6% OOIP than water flood, which has some benefit of economy and society.So it offers a new method of enhanced oil recovery in high temperature and salinity reservoir.