Microemulsion flooding composition for oil field

Abstract

The invention relates to a microemulsion displacement composition for oilfields, which comprises the following components: (1) 20-30 wt% of anionic-nonionic surfactant disclosed as the following formula; (2) 20-30 wt% of one or more of alkyl alcohol polyethenoxy ether, alkylphenol polyoxyethylene, fatty acid polyethenoxy ether, fatty amine polyethenoxy ether, castor oil polyethenoxy ether and sorbitan polyethenoxy ether; (3) 10-20 wt% of one or more of C1-C20 alcohols; and (4) 20-50 wt% of tap water. The preparation method comprises the following step: uniformly mixing the components at normal temperature under normal pressure to prepare the water-soluble liquid. The microemulsion composition integrates the functions of regulation and displacement, is especially suitable for enhancing oil recovery rate under high-temperature high-salt heterogeneous reservoir conditions, and has the characteristics of low consumption, wide application range and the like; the composition can be used for both microemulsion displacement and active water displacement and has low use concentration (only 1%), and the active water displacement concentration is only 0.4%; and the composition is widely used in oil production techniques.

Description

technical field [0001] The invention relates to an emulsion liquid flooding agent for oilfield exploitation, in particular to a microemulsion oil flooding composition for oilfields. Background technique [0002] At present, the oil displacement method of oilfields entering the stage of tertiary oil recovery is usually polymer flooding. The viscosity of the polymer solution is used to improve the mobility ratio of the displacement fluid, increase the displacement efficiency and the swept volume. Mining played a role. The Chinese patent with the publication number CN 103881676 A discloses an oil-external emulsion oil displacement agent, which consists of 0.8 g of polyisobutylene succinate, 60 ml of heavy oil and 140 ml of tap water. But this method has the following disadvantages or deficiencies: ① The oil displacement agent contains 30% of heavy oil, when the injection volume is 0.3PV, it is equivalent to injecting 9% of the formation void volume, which is unimaginable in pr...

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Problems solved by technology

But this method has the following disadvantages or deficiencies: ① The oil displacement agent contains 30% of heavy oil, when the injection volume is 0.3PV, it is equivalent to injecting 9% of the formation void volume, which is unimaginable in practical applications ; 2. The viscosity of the oil-displacing agent is 2000-100000mPa s, and there will be practical problems such as injection difficulties, excessive pressure, and the need for continuous heating of the oil-displacing agent in field application; 3. The oil-displacing agent is only completed under laboratory conditions, and there is no Enter field application; ④ only considering the mobility control, the oil washing efficiency is only the effect of water flooding, and it is powerless for the reservoirs that are difficult to be displaced by water flooding; ⑤ For the formation with serious heterogeneity, subsequent water flooding will break through the plugging It penetrates the strata first, causing the heavy oil in the oil displacement agent to stay in the stratum, causing damage to the first oil layer, and it is difficult to judge the oil displacement effect of the second pair, which may outweigh the gain.

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