Surfactant as well as preparation method and application thereof

Abstract

The invention provides a surfactant as well as a preparation method and an application thereof. The surfactant comprises the following components by mass percent: 45%-65% of aliphatic alcohol polyoxyethylene ether sulfonate, 20%-35% of a cationic surfactant and 10%-20% of a surfactant assistant, wherein a molecular formula of the aliphatic alcohol polyoxyethylene ether sulfonate is CnH[2n+1]-(CH2CH2O)m-SO3Na, n is an any integer ranging from 12 to 15, and m is an any integer ranging from 2 to 5. The invention further provides the preparation method for the surfactant and the application of the surfactant to tertiary oil recovery of a carbonate reservoir. The surfactant is independently used, does not need to be added with alkali, and is free of damage to a stratum and an oil well; an oil washing system prepared from the surfactant can effectively change the wettability of a rock surface and strip off crude oil adsorbed on the surface of a carbonate rock, and the oil washing efficiency reaches more than 60%.

Description

technical field

[0001] The invention belongs to the field of oilfield chemistry, and in particular relates to a surfactant and its preparation method and application. Background technique

[0002] The reserves of carbonate rock reservoirs account for more than half of the world's proven oil and gas reserves, and the production accounts for more than 60%. Its development is very important. my country is rich in carbonate rock oil and gas resources, and carbonate rock oil and gas reservoirs have been found in Sichuan, Tarim, Ordos, Qaidam and other basins. Carbonate reservoirs generally have natural fractures, low porosity and low permeability, and the rock wettability of many carbonate reservoirs is oil-wet / mixed-wet. In addition, unlike sandstone, the surface of carbonate rock is positively charged, and the application effect of conventional anionic surfactants is poor. Foreign countries began to study the tertiary oil recovery of carbonate rocks about 20 years earlier tha...

Examples

Embodiment 1

[0035] This embodiment provides a kind of fatty alcohol polyoxyethylene ether sulfonate, and the specific preparation steps are:

[0036] In a 250mL three-necked flask, add 12.89g (0.03mol) polyoxyethylene lauryl ether and 0.81g sodium metal, add 25mL toluene as a solvent, start stirring, and 2 Under the protection of , the temperature was raised rapidly to 115°C for reflux reaction for 4 hours to obtain sodium alkoxide;

[0037] Add sodium 2-chloroethylsulfonate (the molar ratio of sodium 2-chloroethylsulfonate to polyoxyethylene lauryl ether is 1:1.2), and react at 60°C for 7h;

[0038] Remove toluene by rotary evaporation, add 120mL of absolute ethanol, reflux at 80°C for 30min, filter with suction, cool the filtrate, and crystallize the product sodium dodecyl alcohol polyoxyethylene ether sulfonate (AESO); recrystallize 3 times, dry at 80°C, Weighing, the yield is 80%.

Embodiment 2

[0040] This embodiment provides a surfactant and an oil washing system.

[0041] The preparation steps of this tensio-active agent are:

[0042] The sodium lauryl alcohol polyoxyethylene ether sulfonate, dodecyltrimethylammonium bromide, and hexanol that were synthesized in Example 1 were fully mixed in proportions of 60%, 30%, and 10% by mass fraction to obtain a surface active agent;

[0043] The preparation steps of this washing oil system are:

[0044] Add the above surfactant into an appropriate amount of water, heat and stir for 60 minutes to fully dissolve, then add formation water to prepare a solution with a concentration of 0.15 wt%, and stir for 30 minutes to obtain the oil washing system ①.

Embodiment 3

[0046] This embodiment provides a surfactant and an oil washing system.

[0047] The preparation steps of this tensio-active agent are:

[0048] The sodium dodecyl alcohol polyoxyethylene ether sulfonate, dodecyltrimethylammonium bromide, and hexanol synthesized in Example 1 are fully mixed in proportions of 55%, 30%, and 15% by mass fraction to obtain a surface active agent;

[0049] The preparation steps of this washing oil system are:

[0050] Add the above-mentioned surfactant into an appropriate amount of water, heat and stir for 60 minutes to fully dissolve it, continue to add formation water to prepare a solution with a concentration of 0.15 wt%, and stir for 30 minutes to obtain the oil washing system ②.

technical field

[0001] The invention belongs to the field of oilfield chemistry, and in particular relates to a surfactant and its preparation method and application. Background technique

[0002] The reserves of carbonate rock reservoirs account for more than half of the world's proven oil and gas reserves, and the production accounts for more than 60%. Its development is very important. my country is rich in carbonate rock oil and gas resources, and carbonate rock oil and gas reservoirs have been found in Sichuan, Tarim, Ordos, Qaidam and other basins. Carbonate reservoirs generally have natural fractures, low porosity and low permeability, and the rock wettability of many carbonate reservoirs is oil-wet / mixed-wet. In addition, unlike sandstone, the surface of carbonate rock is positively charged, and the application effect of conventional anionic surfactants is poor. Foreign countries began to study the tertiary oil recovery of carbonate rocks about 20 years earlier tha...

Examples

Embodiment 1

[0035] This embodiment provides a kind of fatty alcohol polyoxyethylene ether sulfonate, and the specific preparation steps are:

[0036] In a 250mL three-necked flask, add 12.89g (0.03mol) polyoxyethylene lauryl ether and 0.81g sodium metal, add 25mL toluene as a solvent, start stirring, and 2 Under the protection of , the temperature was raised rapidly to 115°C for reflux reaction for 4 hours to obtain sodium alkoxide;

[0037] Add sodium 2-chloroethylsulfonate (the molar ratio of sodium 2-chloroethylsulfonate to polyoxyethylene lauryl ether is 1:1.2), and react at 60°C for 7h;

[0038] Remove toluene by rotary evaporation, add 120mL of absolute ethanol, reflux at 80°C for 30min, filter with suction, cool the filtrate, and crystallize the product sodium dodecyl alcohol polyoxyethylene ether sulfonate (AESO); recrystallize 3 times, dry at 80°C, Weighing, the yield is 80%.

Embodiment 2

[0040] This embodiment provides a surfactant and an oil washing system.

[0041] The preparation steps of this tensio-active agent are:

[0042] The sodium lauryl alcohol polyoxyethylene ether sulfonate, dodecyltrimethylammonium bromide, and hexanol that were synthesized in Example 1 were fully mixed in proportions of 60%, 30%, and 10% by mass fraction to obtain a surface active agent;

[0043] The preparation steps of this washing oil system are:

[0044] Add the above surfactant into an appropriate amount of water, heat and stir for 60 minutes to fully dissolve, then add formation water to prepare a solution with a concentration of 0.15 wt%, and stir for 30 minutes to obtain the oil washing system ①.

Embodiment 3

[0046] This embodiment provides a surfactant and an oil washing system.

[0047] The preparation steps of this tensio-active agent are:

[0048] The sodium dodecyl alcohol polyoxyethylene ether sulfonate, dodecyltrimethylammonium bromide, and hexanol synthesized in Example 1 are fully mixed in proportions of 55%, 30%, and 15% by mass fraction to obtain a surface active agent;

[0049] The preparation steps of this washing oil system are:

[0050] Add the above-mentioned surfactant into an appropriate amount of water, heat and stir for 60 minutes to fully dissolve it, continue to add formation water to prepare a solution with a concentration of 0.15 wt%, and stir for 30 minutes to obtain the oil washing system ②.

Images