CN107652963B

CN107652963B - Natural gas foam stabilizer system and preparation method thereof

Info

Publication number: CN107652963B
Application number: CN201710956686.5A
Authority: CN
Inventors: 徐龙; 宫厚健; 刘晨光; 邱喆; 董明哲; 李亚军; 朱腾
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2017-10-13
Filing date: 2017-10-13
Publication date: 2020-03-27
Anticipated expiration: 2037-10-13
Also published as: CN107652963A

Abstract

The invention discloses a natural gas foam stabilizing agent system, which is composed of the following components in mass percentage: nanoparticle dispersion liquid 22.7%-56.8%, surfactant 0.006%-0.01%, ^and mineralized water 5000-100000 mg·L- ¹ . The invention also discloses a preparation method of a natural gas foam foam stabilizer system. The steps include: adding NaCl or CaCl ₂ into water at room temperature and stirring evenly to prepare mineralized water; The fatty alcohol polyoxyethylene ether sodium sulfate is then added to the nano-SiO ₂ particle dispersion, and the mixture is stirred evenly to obtain a natural gas foam system. In the present invention, the surface-modified positively charged nano-SiO ₂ and the anion-nonionic surfactant fatty alcohol polyoxyethylene ether sodium sulfate with an EO number of 3 have significant synergistic effects, which can not only improve the natural gas foaming ability, but also It greatly enhances the stability of natural gas foam and greatly promotes the application of natural gas foam system in tertiary oil recovery in oil and gas field development.

Description

Natural gas foam stabilizer system and preparation method thereof

Technical Field

The invention relates to the field of oilfield chemistry, in particular to a natural gas foam stabilizer system and a preparation method thereof.

Background

At present, in the development process of oil fields in China, gas injection flooding is one of the commonly used technologies for improving the recovery ratio, but because of higher fluidity of gas and heterogeneity of oil reservoirs, the viscous fingering phenomenon is easy to generate, so that the sweep coefficient is lower, and the effect of improving the recovery ratio is limited. Foams tend to exhibit higher apparent viscosities in formations as a gas-liquid two-phase mixed fluid. Moreover, the foam can block a high-permeability layer and improve the sweep coefficient of a low-permeability layer; the oil-water-resistant agent is broken and killed when meeting oil, is stable when meeting water and has the performance of selectively plugging oil and water. Therefore, under the conditions of high water content and increasingly outstanding stratum heterogeneity of the oil field, the foam system has important significance for further improving the oil reservoir recovery efficiency. However, the foam system is a thermodynamically unstable system and is affected by the oil phase, so that the stability under the oil reservoir condition is worse, and the application of the foam flooding is limited.

At present, the development of foaming agents for foam systems mainly focuses on the synthesis or compounding of surfactants, and the obtained foam systems can generate enough foam volume, but have short half-life and poor stability. In order to enhance stability, polymers such as polyacrylamide and the like are often added into a foaming agent, and although the substances can play a role in enhancing foam stability, the foaming volume is low, high salt is easy to reduce viscosity, high temperature is easy to decompose, the use of the substances in high-temperature and high-salt oil reservoirs is not facilitated, and the remaining organic residues can also cause damage to stratums, so that the search for a foam system which has high foaming efficiency and good stability in a high-temperature and high-salt environment is a key task for developing a foam flooding technology. In the prior art, anionic surfactant (SDS) and hydrophobic nano silicon dioxide (SiO)₂) The stability properties of air foams stabilized by particles were investigated experimentally. The result shows that the hydrophobic nano SiO₂The particles can enhance the stability of air foam, and the nano SiO₂The hydrophobic group has hydrophobic interaction with the hydrophobic chain of SDS, and the nano SiO₂Is attracted to a gas-liquid interface to form a skeleton structure, increases the mechanical strength of foam, plays a role in stabilizing the foam, and is used as a material for preparing SDS and SiO₂The foam stability is best when the content is 0.5% and 1.5%, respectively. However, with CaCl₂Addition of SDS/SiO₂The foaming volume and the stability of the system are reduced, and the nano SiO with hydrophobic modification₂The SDS head group and the SDS head group are both negatively charged, and electrostatic repulsion action exists between the SDS head group and the SDS head group, so that partial attraction between the SDS head group and the SDS head group can be counteracted, and the nano SiO is weakened₂Adsorption at the gas-liquid interface further affects the stability of the foam. At present, the foams researched at home and abroad mainly focus on foam systems formed by air, nitrogen, carbon dioxide, flue gas and the like,very few studies have been reported on natural gas foam systems and their stability.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a natural gas foam stabilizer system and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

a natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂2.8-56.8% of particle dispersion liquid, 0.001-0.012% of surfactant and the balance of mineralized water.

The nano SiO₂The particle dispersion is surface modified positively charged nano SiO with particle diameter of 10-15nm₂The particles were uniformly dispersed in water, with an effective solids content of 17.6%.

Preferably, the natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂22.7 to 56.8 percent of particle dispersion liquid, 0.006 to 0.01 percent of surfactant and the balance of mineralized water.

Preferably, the surface modified positively charged nano SiO₂The surface of the particles is made of Al₂O₃Covering, Al₂O₃In the nano SiO₂The solids content in the particle dispersion was 2.3%. The modified nano SiO₂The particle dispersion is commercially available and available from Aladdin reagent (Shanghai) Co., Ltd. Can also be prepared according to the prior art.

Preferably, the surfactant is an anionic-nonionic surfactant sodium fatty alcohol polyoxyethylene ether sulfate.

Preferably, the number of the oxyethylene groups (EO) of the sodium fatty alcohol polyoxyethylene ether sulfate is 3.

Preferably, the mineralized water is made of NaCl or CaCl₂Prepared with mass concentration of 100000mg.L of 5000-^-1。

The invention also discloses a preparation method of the natural gas foam stabilizer system, which comprises the following steps:

NaCl or CaCl is added at normal temperature₂Adding into water, stirring to obtain mineralized water, mixing the above components at a certain ratio, adding into EO number 3 sodium polyoxyethylene fatty alcohol sulfate, and adding into nanometer SiO₂And (4) uniformly stirring the particle dispersion liquid to obtain the natural gas foam stabilizer system. The system improves the foaming property and foam stability of natural gas foam through the synergistic effect of the nano particles/the surfactant, and is suitable for high-temperature and high-salt environments.

According to the invention, the natural gas foam stabilizer system is applied to the gas flooding or foam flooding oil extraction process of oil exploitation.

The invention has the beneficial effects that:

(1) the invention selects the nanometer SiO₂The particles and the fatty alcohol-polyoxyethylene ether sodium sulfate surfactant can generate stronger interaction in aqueous solution. This is mainly due to the selected nano SiO₂The surface-modified positively-charged particles are prepared by using fatty alcohol-polyoxyethylene ether sodium sulfate as an anionic-nonionic surfactant, electrostatic mutual attraction exists between the surface-modified positively-charged particles and the surface-modified positively-charged particles due to opposite charges, and meanwhile, the fatty alcohol-polyoxyethylene ether sodium sulfate contains oxyethylene groups which are in aqueous solution with nano SiO₂The silanol groups on the surface can generate hydrogen bond action, so that the surface has stronger interaction. In addition, the sodium fatty alcohol-polyoxyethylene ether sulfate has the advantages of both anionic surfactants and nonionic surfactants, so that the defect of poor salt tolerance of the anionic surfactants can be overcome, and the defect of poor rock adsorption resistance of the nonionic surfactants can be overcome.

(2) The invention selects the nanometer SiO₂The particles and the fatty alcohol-polyoxyethylene ether sodium sulfate can generate synergistic action, and the composite use of the particles and the fatty alcohol-polyoxyethylene ether sodium sulfate can generate an effect obviously superior to that of a single system, and the effect is shown to have better foamability and foam stability. This is mainly due to the positively charged nano-SiO₂The particles and the sodium fatty alcohol-polyoxyethylene ether sulfate are compounded in the water solution to generate a viscosityWhen the flocculating constituent is mixed with natural gas, because the methane molecules and the EO groups of the fatty alcohol-polyoxyethylene ether sodium sulfate generate interaction, compared with nitrogen and carbon dioxide, the flocculating constituent is easier to adsorb on the flocculating constituent, and the flocculating constituent wraps the natural gas to form viscous bubbles to collect foam with a viscous film. Due to the sealing property of the viscous membrane, the loss of liquid in the foam liquid membrane can be effectively inhibited, the diffusion of natural gas is reduced, and the phenomenon that large bubbles are larger and small bubbles are smaller and smaller until the large bubbles disappear is effectively avoided. Meanwhile, the viscous membrane has certain deformability, and has a certain repairing function on the deformation of bubbles caused by external interference, so that the stability of the natural gas foam can be improved.

(3) Under the condition of high temperature and high salt, the nano SiO₂The natural gas foam produced by the particle/sodium fatty alcohol polyoxyethylene ether sulfate synergy shows excellent foaming property and long-term stability. NaCl and CaCl₂Can improve the surface tension reducing efficiency and capacity of the sodium alcohol ether sulphate, promote the sodium alcohol ether sulphate to form worm-shaped micelle solution, and CaCl₂The effect of (D) is stronger than that of NaCl. The Ca ions are adsorbed on the surface of the fatty alcohol-polyoxyethylene ether sodium sulfate micelle, and a part of Ca ions are inserted near an oxyethylene group (EO) with the characteristic of a nonionic surfactant to perform complexation with the EO group, so that the capability of promoting the growth of the micelle by counter ions is improved. Therefore, NaCl and CaCl₂Can promote the nano SiO₂The interaction between the particles and the sodium fatty alcohol polyoxyethylene ether sulfate further enhances the stability of the natural gas foam.

(4) The EO number in the sodium fatty alcohol polyoxyethylene ether sulfate is 3. Too much or too little EO number can affect the solubility of the sodium fatty alcohol polyoxyethylene ether sulfate in the aqueous solution, and further affect the sodium fatty alcohol polyoxyethylene ether sulfate and the nano SiO₂The interaction of the particles.

(5) The interfacial tension between natural gas and water decreases with increasing pressure and temperature and is lower than that of air and water. Moreover, the natural gas reserves in the oil reservoir are rich, local materials are convenient to obtain, the hydrocarbon components and the water-phase foaming agent are easier to form foams, and the viscosity of the oil phase can be reduced after the natural gas is dissolved in the oil, so that favorable conditions are provided for the development and application of the natural gas foams.

(6) The invention surface-modified positively-charged nano SiO₂The particle dispersion liquid and the anionic-nonionic surfactant fatty alcohol-polyoxyethylene ether sodium sulfate have obvious synergistic effect, so that the foaming capacity of natural gas can be improved, the foam stability of the natural gas can be greatly enhanced, and the application of a natural gas foam system in tertiary oil recovery in oil and gas field development is greatly promoted.

Drawings

FIG. 1 shows mineralized water prepared with NaCl at 100000mg.L^-1At degree of mineralization, 22.7% nano SiO₂A graph of the foam height and the change of the foam height with time of natural gas foam generated by the particle dispersion, the 0.006% fatty alcohol polyoxyethylene ether sodium sulfate with EO number of 3 and the compound system of the two; in the figure, NPS and APES respectively refer to modified nano SiO₂A particle dispersion and sodium fatty alcohol polyoxyethylene ether sulfate with EO number of 3;

FIG. 2 is a view of nano SiO₂Particle dispersion/fatty alcohol-polyoxyethylene ether sodium sulfate composite system with EO number of 3 and nano SiO₂A graph comparing the foam height of natural gas of a particle dispersion/sodium dodecyl benzene sulfate composite system with time; nano SiO₂The mass fraction of the particle dispersion liquid is 22.7 percent, and the mass fractions of the fatty alcohol-polyoxyethylene ether sodium sulfate and the lauryl sodium sulfate with EO number of 3 are both 0.006 percent; SDS in the figure means sodium dodecyl sulfate;

FIG. 3 shows 100000mg.L of NaCl prepared at 50 ℃^-1Under the mineralized water environment, the nano SiO₂Particle dispersion/fatty alcohol-polyoxyethylene ether sodium sulfate composite system with EO number of 3 and nano SiO₂A graph comparing the foam height of natural gas of a particle dispersion/sodium dodecyl benzene sulfate composite system with time; nano SiO₂The mass fraction of the particle dispersion liquid is 22.7 percent, and the mass fractions of the fatty alcohol-polyoxyethylene ether sodium sulfate and the lauryl sodium sulfate with EO number of 3 are both 0.006 percent;

FIG. 4 shows that at 50 ℃ and different NaCl concentrations, 22.7% of nano-SiO₂Particle Dispersion/0.006% fatty alcohol polyoxyethylene Ether Sulfur with EO number 3A graph of the change of the foam height of the natural gas of the sodium salt composite system along with time;

FIG. 5 shows the difference of CaCl at 50 ℃₂At concentration, 22.7% nano SiO₂Graph of foam height of natural gas of particle dispersion/0.006% sodium fatty alcohol polyoxyethylene ether sulfate composite system with EO number of 3 as a function of time.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Nano SiO used in this example₂The particle dispersion is a commercially available product from Aladdin reagent (Shanghai) Co., Ltd, in which the nano SiO is₂The particle dispersion liquid is surface modified nano SiO with positive charge₂The particle dispersion suspension liquid contains water as dispersant, the particle size of the particles is 10-15nm, and the effective solid content is 17.6%. Nano SiO₂The surface of the particles is made of Al₂O₃Covering, Al₂O₃In the nano SiO₂The solid content in the particle dispersion was 2.3%; the surfactant is anionic-nonionic surfactant sodium fatty alcohol polyoxyethylene ether sulfate and contains 3 oxyethylene groups.

Example 1

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂22.7 percent of particle dispersion liquid, 0.006 percent of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 and the balance of mineralized water, wherein the mineralized water is prepared from NaCl and has the total mineralization degree of 100000mg.L^-1。

The preparation method comprises the following steps: adding NaCl into water at normal temperature, stirring uniformly to prepare mineralized water, dissolving 0.1gEO fatty alcohol-polyoxyethylene ether sodium sulfate with the number of 3 in 1665.9g of mineralized water, stirring uniformly to obtain 0.006% EO number 3 fatty alcohol-polyoxyethylene ether sodium sulfate aqueous solution, taking 15.46g of the aqueous solution, and gradually adding 4.54g of nano SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation test of foam Properties, 100000mg. multidot.L in NaCl as shown in FIG. 1^-1Under the mineralized water environment, 22.7 percent of nano SiO is singly used₂The particle dispersion can only generate a very small amount of foam, has poor foaming capability and cannot effectively generate foam; the single sodium alcohol ether sulphate system with 0.006 percent EO number of 3 can generate more foams, has good foaming capacity, but has poor foam stability because the half-life period of the foam is only 3.7 hours; 22.7% nano SiO₂The particle dispersion/fatty alcohol-polyoxyethylene ether sodium sulfate composite system with EO number of 3 of 0.006 percent can generate a large amount of foam, and the half-life period of the foam is 115 hours, which is far better than that of a single system. Nano SiO₂The fatty alcohol-polyoxyethylene ether sodium sulfate composite system with the particle dispersion liquid/EO number of 3 has a remarkable synergistic effect, can generate more foams, has longer foam stabilizing time, namely, the two are used in a composite manner, has better foamability and foam stability, and can generate an effect obviously superior to that of a single system. This is mainly due to the positively charged nano-SiO₂The particles and the fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 can generate stronger interaction in aqueous solution, and not only has electrostatic interaction attraction effect, but also has hydrogen bond effect. The two are used in a combined way to generate a viscous flocculating constituent which can form a viscous membrane with a self-repairing function and has the effect of stabilizing natural gas foam.

Example 2

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂22.7 percent of particle dispersion liquid, 0.006 percent of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 and the balance of mineralized water, wherein the mineralized water is CaCl₂Prepared with the total mineralization degree of 100000mg.L^-1。

The preparation method comprises the following steps: at normal temperature adding CaCl₂Adding into water, stirring to obtain mineralized water, dissolving 0.1gEO fatty alcohol polyoxyethylene ether sodium sulfate (number 3) in 1665.9g of mineralized water, stirring to obtain 0.006% EO number 3 fatty alcohol polyoxyethylene ether sodium sulfate aqueous solution, collecting 15.46g, and gradually adding 4.54g nanometer SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation of foam Properties in CaCl₂100000mg.L of the preparation^-1Under the mineralized water environment, 22.7 percent of nano SiO is singly used₂The particle dispersion has poor foaming ability and cannot effectively generate foam; the single sodium alcohol ether sulphate system with 0.006 percent EO number of 3 can generate more foam, and the half-life period of the foam is 3.9 hours; 22.7% nano SiO₂The particle dispersion/fatty alcohol polyoxyethylene ether sodium sulfate composite system with EO number of 3 of 0.006 percent can generate a large amount of foam, and the half-life period of the foam is 121 hours, which is far better than that of a single system.

Example 3

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂56.8 percent of particle dispersion liquid, 0.012 percent of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3, and the balance of mineralized water, wherein the mineralized water is prepared by NaCl, and the total mineralization is 100000mg.L^-1。

The preparation method comprises the following steps: adding NaCl into water at normal temperature, stirring uniformly to prepare mineralized water, dissolving 0.2gEO fatty alcohol-polyoxyethylene ether sodium sulfate with the number of 3 in 1665.8g of mineralized water, stirring uniformly to obtain 0.012% EO number 3 fatty alcohol-polyoxyethylene ether sodium sulfate aqueous solution, taking 8.64g of the aqueous solution, gradually adding 11.36g of nano SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation test of foam Properties, 100000mg. L in NaCl^-1Under the mineralized water environment, 56.8 percent of nano SiO is singly used₂The particle dispersion has poor foaming ability and cannot effectively generate foam; the single sodium alcohol ether sulphate system with 0.012 percent EO number of 3 can produce more foams, and the half-life period of the foams is 5.4 hours; 56.8% nanometer SiO₂The composite system of particle dispersion liquid/fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 of 0.012 percent can generate a large amount of foam, and the half-life period of the foam is 158 hours, which is far better than that of a single system.

Example 4

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂56.8% of particle dispersion liquid, 0.012% of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 and the balance ofMineralized water made of CaCl₂Prepared with the total mineralization degree of 100000mg.L^-1，

The preparation method comprises the following steps: at normal temperature adding CaCl₂Adding into water, stirring to obtain mineralized water, dissolving 0.2gEO number 3 sodium alcohol ether sulfate in 1665.8g of mineralized water, stirring to obtain 0.012% EO number 3 sodium alcohol ether sulfate aqueous solution, collecting 8.64g, gradually adding 11.36g nanometer SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation of foam Properties in CaCl₂100000mg.L of the preparation^-1Under the mineralized water environment, 56.8 percent of nano SiO is singly used₂The particle dispersion has poor foaming ability and cannot effectively generate foam; the single sodium alcohol ether sulphate system with 0.012 percent EO number of 3 can produce more foams, and the half-life period of the foams is 5.7 hours; 56.8% nanometer SiO₂The composite system of the particle dispersion liquid/the fatty alcohol-polyoxyethylene ether sodium sulfate with 0.012 percent of EO number of 3 can generate a large amount of foam, and the half-life period of the foam is 164 hours, which is far better than that of a single system.

Example 5

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂56.8 percent of particle dispersion liquid, 0.006 percent of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 and the balance of mineralized water, wherein the mineralized water is prepared from NaCl and has the total mineralization degree of 100000mg.L^-1。

The preparation method comprises the following steps: adding NaCl into water at normal temperature, stirring uniformly to prepare mineralized water, dissolving 0.1gEO fatty alcohol-polyoxyethylene ether sodium sulfate with the number of 3 in 1665.9g of mineralized water, stirring uniformly to obtain 0.006% EO number 3 fatty alcohol-polyoxyethylene ether sodium sulfate aqueous solution, taking 8.64g of the aqueous solution, and gradually adding 11.36g of nano SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation experiment of foam Property, 100000mg.L prepared with NaCl at 50 ℃^-1In mineralized water environment, mono56.8 percent of nano SiO₂The particle dispersion has poor foaming ability and cannot effectively generate foam; the sodium fatty alcohol polyoxyethylene ether sulphate system with 0.006% EO number 3 alone produced some foam with a foam half life of 0.4 hours; 56.8% nanometer SiO₂The particle dispersion/fatty alcohol polyoxyethylene ether sodium sulfate composite system with EO number of 3 of 0.006 percent can generate a large amount of foam, and the half-life period of the foam is 79 hours, which is far better than that of a single system.

Example 6

A natural gas foam stabilizer system comprises the following components in percentage by mass: nano SiO₂56.8 percent of particle dispersion liquid, 0.006 percent of fatty alcohol-polyoxyethylene ether sodium sulfate with EO number of 3 and the balance of mineralized water, wherein the mineralized water is CaCl₂Prepared with the total mineralization degree of 100000mg.L^-1，

The preparation method comprises the following steps: at normal temperature adding CaCl₂Adding into water, stirring to obtain mineralized water, dissolving 0.1gEO fatty alcohol polyoxyethylene ether sodium sulfate (number 3) in 1665.9g of mineralized water, stirring to obtain 0.006% EO number 3 fatty alcohol polyoxyethylene ether sodium sulfate aqueous solution, collecting 8.64g, gradually adding 11.36g nanometer SiO₂And uniformly mixing the particle dispersion liquid to obtain the natural gas foam stabilizer system suitable for the high-temperature and high-salinity environment.

Evaluation experiment of foam Properties, CaCl 50 ℃₂100000mg.L of the preparation^-1Under the mineralized water environment, 56.8 percent of nano SiO is singly used₂The particle dispersion has poor foaming ability and cannot effectively generate foam; the sodium fatty alcohol polyoxyethylene ether sulphate system with 0.006% EO number 3 alone produced some foam with a foam half life of 0.5 hours; 56.8% nanometer SiO₂The particle dispersion/fatty alcohol-polyoxyethylene ether sodium sulfate composite system with EO number of 3 of 0.006 percent can generate a large amount of foam, and the half-life period of the foam is 83 hours, which is far better than that of a single system.

As shown in FIG. 2, nano SiO₂The particle dispersion/sodium lauryl sulfate composite system also has a synergistic effect, i.e., the foamability and foam stability of the two composite systems are higher than those of a single system. But with nano SiO₂Particle dispersion/fatCompared with a fatty alcohol polyoxyethylene ether sodium sulfate composite system, the foaming property and the foam stability of the latter are obviously better. This is mainly because the sodium polyoxyethylene fatty alcohol sulfate with EO number of 3 contains EO groups, EO groups and nano SiO which are not contained in sodium lauryl sulfate₂Can form hydrogen bond action to further strengthen the nano SiO₂And sodium fatty alcohol polyoxyethylene ether sulfate.

As shown in FIG. 3, 100000mg.L of NaCl at 50 ℃ was prepared^-1Under the mineralized water environment, the nano SiO₂The half-life period of the natural gas foam of the fatty alcohol-polyoxyethylene ether sodium sulfate composite system with the particle dispersion liquid/EO number of 3 is 115 hours, and the stability is obviously higher than that of the nano SiO under the same condition₂Particle dispersion/sodium lauryl sulfate composite system natural gas foam (half life 38 hours).

As shown in FIG. 4, the NaCl concentration was between 5000 and 100000mg.L at 50 deg.C^-1When the nano SiO is used, the nano SiO can be obviously enhanced₂The stability of the fatty alcohol-polyoxyethylene ether sodium sulfate composite system natural gas foam with the particle dispersion liquid/EO number of 3 shows that the composite system natural gas foam is suitable for a high-temperature and high-salt environment.

As shown in FIG. 5, at 50 ℃ when CaCl is added₂The concentration is 5000-100000 mg.L^-1When the nano SiO is used, the nano SiO can be obviously enhanced₂The stability of the fatty alcohol-polyoxyethylene ether sodium sulfate composite system natural gas foam with the particle dispersion liquid/EO number of 3 shows that the composite system natural gas foam is suitable for a high-temperature and high-salt environment.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. a natural gas foam stabilizer system, is characterized in that, is made up of the following components by mass percentage: nanoparticle dispersion 22.7%-56.8%, surfactant 0.001%-0.012%, and the rest are mineralized water;

The nano-SiO ₂ particle dispersion liquid is composed of surface-modified positively charged nano-SiO ₂ particles with a particle size of 10-15nm uniformly dispersed in water, wherein the effective solid content is 17.6%;

The surfactant is an anionic-nonionic surfactant fatty alcohol polyoxyethylene ether sodium sulfate.

2. A natural gas foam stabilizing agent system as claimed in claim 1, characterized in that, it is composed of the following components by mass percentage: nanoparticle dispersion 22.7%-56.8%, surfactant 0.006%-0.012%, The rest is mineralized water.

3. A kind of natural gas foam stabilizing agent system as claimed in claim 2, is characterized in that, the surface of described surface-modified positively charged nano-SiO ₂ particle surface is covered by Al ₂ O ₃ , and Al ₂ O ₃ is in nano-SiO 3 ₂ The solids content in the particle dispersion was 2.3%.

4. a kind of natural gas foam stabilizer system as claimed in claim 2, is characterized in that, the oxyethylene group quantity of described fatty alcohol polyoxyethylene ether sodium sulfate is 3.

5 . The natural gas foam stabilizer system according to claim 2 , wherein the mineralized water is prepared from NaCl or CaCl ₂ , and the total salinity is 5000-100000 mg·L ⁻¹ . 6 .

6. The use of the natural gas foam foam stabilizer system according to any one of claims 1 to 5 for gas flooding or foam flooding in oil production.

7. the preparation method of a kind of natural gas foam foam stabilizer system as claimed in claim 5, it is characterized in that, step is as follows: under normal temperature, _NaCl or CaCl are added in water and stir to prepare mineralized water, get each group by proportioning First, add aliphatic alcohol polyoxyethylene ether sulfate sodium sulfate with EO number of 3, then add nano-SiO ₂ particle dispersion liquid, and stir evenly to obtain a natural gas foam foam stabilizer system.