A kind of improved betaine surfactant composition system and its application

Abstract

The invention discloses an improved betaine surfactant composition system and an application thereof. The system comprises betaine surfactants and oil well injected water, wherein the betaine surfactants are selected from more than any two types of alkyl dimethyl betaine, alkyl amido propyl dimethyl betaine, alkyl sulpho betaine and alkyl hydroxyl sulpho betaine; and in the system, the total concentration range of all the surfactants in terms of 100% of activity is 0.005-1%. The betaine surfactant composition system provided by the invention has strong capacity of resisting the degree of mineralization, good matching with polymers particular PAM (polyacrylamide) type polymers and high temperature stability, is used for three times of chemical displacement of reservoir oil to ensure that 10-15% more of oil reservoirs can be exploited, and is low in using concentration, so that the cost is greatly reduced; and moreover, the betaine surfactant composition system does not contain alkali, so that the selection of polymers is wider, and the significance for protecting natural resources is also very important.

Description

Technical field [0001] The invention belongs to the field of oilfield development, and relates to a chemical flooding additive for oilfield development. Specifically, it relates to an improved betaine surfactant composition system and its use, which is suitable for low surfactant concentration and no alkali added. Chemical flooding system (ie, chemical flooding system). Background technique [0002] In normal oilfield development, the first method of exploitation is to exploit the energy of the oil layer itself, that is, one-time oil recovery. At this stage, crude oil erupts with the well pipe on its own energy. Usually about 15-20% of oil reservoirs are developed by one-time oil recovery. With the deepening of exploitation, when natural energy cannot meet the demand due to attenuation, water or gas needs to be injected into the oil layer to maintain the production or recovery rate of the oil well. This is the secondary oil recovery stage. Another 15-20% of crude oil reserves ...

AI Technical Summary

Problems solved by technology

[0009]However, the traditional three-component compounding technology is used for tertiary oil recovery in oil field development, the main problems are: 1) The long-term use of alkali will cause formation damage , causing negative effects on oil recovery and the environment; 2) The use of alkali causes instability and decomposition of some surfactants and polymers, limiting the selection of surfactants and polymers

[0019] 1) Even if there are many lipophilic and hydrophilic groups to choose from, often the most ideal lipophilic and hydrophilic groups only exist on paper and cannot be realized in reality;

[0020] 2) Even if the ideal surfactant can be synthesized in the laboratory, due to the limitations of raw materials, process, cost, etc., the experimental results cannot be promoted to industrial products that can be mass-produced

[0021] 3) Since crude oil composition, reinjection water composition, formation temperature, polymer and other conditions vary due to the place of origin and application, the single surfactant system lacks room for formulation improvement;

[0022] 4) Possible limitation of the efficacy of betaine surfactant itself

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