Preparation And Application Of ASP Flooding

More and more chemical oil displacement reagents have been used in the proceeding of oil recovery. ASP compound system is one of the best displacement flood .The research of these reagents begin with 1980's in our country.The alkali can react with acidic component come into being active matter. These matter will adsorb on the interfacial, then decrease the IFT. On the other side ,the absorption of alkali can decrease absorptive capacity of surfactant by 30%.The main function of surfactant is reducing IFT. As the character of surfactant, it can drive the oil remains that can t be divorced from rock by water. The super low interfacial tension can be obtained with a low concentration of the surfactants by selection of a proper combination system of surfactants. So it can increase the washing efficiency. As polymer solution have higher viscidity than water, so it can control mobility ratio. Polymer solution can enhance the volumetric coverage of injected water.Put the advantage of alkali, surfactant, polymer together, ASP complex system can not only increase the washing efficiency but also control the mobility, so can increase the recovery factor about 20%.But there are some problem to be solve. For example , scale deposition cause by alkali; the solvency of polymer ;the losing of absorption of chemical reagent; the mechanism of reciprocity of chemical reagent ,and so on.In this paper, oil driving principle of the alkali-surfactant-polymer is described. Mixing the complex inorganic alkali ,surfactant and polymer which all synthesized in the laboratory ,the suitable compound system is provided. Displacement experiment show us that this system is fit for Daqing oil field. Branched-chain alkyl sulfonate surfactants that have low interfacial tensions are synthesized .Through the research of the relation between the interfacial tension and the concentration of the combination system and considering the economic factors .On the other hand, lots of experiments show that the quantity of surfactant decrease when some agents are added. The experiments prove that the lingo-sulfonate can be used as co-surfactant. The addition of alcohol can make the stability and compatibility of the ASP-system increasing. But the addition and the quantity of the alcohol can affect the interfacial tension of the ASP-system. After our experiments, we come up with the conclusion that the adding quantity of alcohol is too much, the interfacial tension of ASP-system will increase. Otherwise, the adding quantity of alcohol is too little, the compatibility of the system will be decreasing. Finally we use iso-prop as agents. The preparation method of the ASP-system have more effect on the property of system. First we solute the HPAM into water, then we add the surfactant and alkali into solution to keep the viscidity of the system.The suitable concentration of surfactants is 0.3wt%~0.6wt%. Polymer used is HPAM with the super high molecular weight. Which is synthesized in the laboratory when its concentration is 1200mg/L.it can reach the necessary viscidity and have no effect on reducing the interfacial tension of the system. A lot of experiments have been done on selecting alkalis including NaOH, Na2CO3> Na3PO4 etc .The result is the best when the ratio of NaOH to Na2SO3 is 7:1 .Using ID-l(0.3% ~ 0.6%), polymer ZDP(1200 ~ 1500mg/L) and combination alkalis (NaOH : Na2SO3 =7:1) , flowing experiences have been done in the laboratory and got a better ingredient in recovery effect and economy.