A kind of low permeability oil field surfactant oil displacement compound system
Technical field
The invention belongs to used for tertiary oil recovery oil field chemical technical field, relate to a kind of surfactant compound system, is a kind of chemical agent that is applicable to low permeability oil field displacement of reservoir oil volume increase.
Background technology
The conventional waterflood recovery efficiency factor of low permeability pay is lower, and at middle and high pervious course, successfully applies the technology (as polymer flooding etc.) that can increase substantially recovery ratio and also because injection pressure is high, formation water salinity is high, cannot apply at low permeability pay.For this reason, for improving low permeability pay recovery ratio difficulty, one of important method of improving water drive raising oil recovery factor is exactly to utilize various chemical agents, and wherein tensio-active agent is considered to improve by a relatively large margin recovery ratio, the scope of application a kind of chemical agent wider, most with prospects.
For single surfactant system, be difficult to form ultra low interfacial tension with crude oil, compound surfactant system adds alkali conventionally, and to form ultra low interfacial tension, but adding of alkali can produce new infringement again to low permeability pay.Therefore, do not add the research that alkali just can form the surfactant compound system of ultra low interfacial tension with crude oil and there is important value to improving the recovery ratio of low permeability pay.The present invention is re-dubbed surfactant system with anion sulfoacid natrium surfactant and nonionogenic tenside, and this system and stratum dewatered oil reach 10
-3～10
-4mN/m ultra low interfacial tension, and this system has resistance to high salinity, resistant to elevated temperatures advantage.
Summary of the invention
The object of this invention is to provide a kind of surfactant oil displacement compound system, by reducing oil water interfacial tension, improve displacement efficiency, for this type of reservoir waterflooding middle and later periods is realized long term stable production, further improve recovery ratio and explore new technological approaches.
1. the component of surfactant compound system and performance
(1) fatty alcohol-polyoxyethylene ether sodium sulfonate
It is the anion surfactant of high temperature resistant, the resistance to high salinity of a class, the calcium of resistance to high price, magnesium ion.
(2) alkylphenol polyoxyethylene
A nonionic surface active agent, is dissolved in oil and other organic solvent, has good emulsifying performance.
2. each constituent mass proportioning
Fatty alcohol-polyoxyethylene ether sodium sulfonate, the composite mass ratio of alkylphenol polyoxyethylene are 2:1, are 30～40% fatty alcohol-polyoxyethylene ether sodium sulfonate by mass percentage, 15～20% alkylphenol polyoxyethylene, and all the other are water.
This surfactant compound system and stratum dewatered oil, in working concentration is 0.2～0.4% scope, at 55 ℃, can reach 10
-3～10
-4mN/m ultra low interfacial tension; And this system is subject to formation water salinity variable effect less, salt tolerant reaches 100,000, and resistance to calcium ion reaches 1600mg/L; The anti-absorption property of this system is better, and dynamic adsorption loss amount is lower than industry standard 0.5mg/g oil-sand.Be suitable for high salinity, the surfactant flooding of high contents of calcium and magnesium ionic concn low-permeability oil deposit.
Embodiment
Embodiment 1
1. in whipping process, quality 17% alkylphenol polyoxyethylene is added to the water, to dissolving completely.
2. stir on limit, and, to the fatty alcohol-polyoxyethylene ether sodium sulfonate that adds quality 34% in Agitation Tank, stir 50 minutes on limit, can form surfactant soln.
The functional quality concentration of this surfactant compound system and stratum dewatered oil is in 0.3% scope, at 55 ℃, can reach 10
-3～10
-4mN/m ultra low interfacial tension.
Embodiment 2
1. in whipping process, quality 15% alkylphenol polyoxyethylene is added to the water, to dissolving completely.
2. stir on limit, and, to the fatty alcohol-polyoxyethylene ether sodium sulfonate that adds quality 30% in Agitation Tank, stir 30 minutes on limit, can form surfactant soln.
The functional quality concentration of this surfactant compound system and stratum dewatered oil is in 0.4% scope, at 55 ℃, can reach 10
-3～10
-4mN/m ultra low interfacial tension.
Embodiment 3
1. in whipping process, quality 20% alkylphenol polyoxyethylene is added to the water, to dissolving completely.
2. stir on limit, and, to the fatty alcohol-polyoxyethylene ether sodium sulfonate that adds quality 40% in Agitation Tank, stir 60 minutes on limit, can form surfactant soln.
The functional quality concentration of this surfactant compound system and stratum dewatered oil is in 0.2% scope, at 55 ℃, can reach 10
-3～10
-4mN/m ultra low interfacial tension.