WO2019054414A1 - Chemical for crude oil recovery - Google Patents

Abstract

[Problem] To provide a chemical for crude oil recovery, which has high crude oil recovery rate, while having excellent salt tolerance at high temperatures. [Solution] A chemical for crude oil recovery, which has excellent salt tolerance at high temperatures, and which is characterized by containing a silane compound, an aqueous silica sol having an average particle diameter of 3-200 nm, two or more anionic surfactants, and one or more nonionic surfactants.

Description

Chemical recovery for crude oil

The present invention is used in surfactant flooding in an enhanced oil recovery (hereinafter referred to as “Enhanced Oil Recovery”) (hereinafter referred to as “EOR”) flooding method in which crude oil is recovered by injecting it into the oil reservoir of inland or submarine oil field The invention relates to a crude oil recovery chemical solution which is excellent in high temperature salt resistance and high in crude oil recovery rate.

As a method of recovering (collecting) crude oil from the oil reservoir, a three-stage method of primary, secondary and tertiary (or EOR (promotion)) is applied in which different recovery methods are applied to each time series.
Primary recovery methods include self-injection oil extraction methods that use the natural pressure and gravity of oil reservoirs, and artificial oil extraction methods that use artificial oil collection techniques such as pumps, etc. Primary oil recovery crude oil implemented by combining these methods The recovery rate is said to be about 20% at the maximum. The secondary recovery method includes a water flooding method and an oil layer pressure maintenance method in which water and natural gas are injected to reduce the oil layer pressure and increase the oil production amount after production declines in the primary recovery method. Even in the combined primary and secondary recovery, the crude oil recovery rate is about 40%, and most of the crude oil remains in the underground oil reservoir. Therefore, in order to recover additional crude oil from the oil reservoir where crude oil is recovered from more, and already easy to recover, proposed is a method of enhanced recovery of crude oil by tertiary recovery method, that is, EOR flooding. ing.

EOR attacks include heat attack, gas attack, microbial attack and chemical attack. Chemical flooding includes polymer flooding, surfactant flooding, micelle flooding, etc. A chemical solution according to the purpose is injected into the oil layer to enhance the fluidity of crude oil, or act between water and oil. In order to improve the recovery rate of crude oil, the surface tension is reduced or a micellar state is created between the injected gas and the oil.

Surfactant flooding reduces the interfacial tension between crude oil and water by forcing a series of fluids containing a surfactant-based solution into the oil layer, and the crude oil trapped by capillary action It is an attack to pull out and collect. In the present method, for example, alkyl allyl sulfonate is used alone as a surfactant, or used together with alkyl allyl sulfonate and a cosurfactant and / or an adjuvant. Alkyl allyl sulfonates are commonly used because they can not only lower the interfacial tension between oil and water, but also exhibit different phase behavior as described below when used with different salt concentrations There is. That is, at low salt concentrations, alkyl allyl sulfonates tend to remain in the aqueous phase, but at high salt concentrations tend to remain in the oil phase. At mid-point salt concentrations, microemulsions are formed and significant amounts of oil and brine are present in the microemulsion phase, which is known to exhibit high crude oil recovery.
Micellar flooding is a method of making a microemulsion from water and crude oil, injecting a microemulsion called a micellar solution into an underground reservoir, and recovering petroleum, and many surfactants are used to produce a micelle solution. Patent documents 1 to 3 have been disclosed. As surfactants used in the present method, petroleum sulfonate, alkyl allyl sulfonate, alkane sulfonate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyhydric alcohol fatty acid ester, alkyl trimethyl ester Various anionic, non-ionic and cationic surfactants such as ammonium salts are disclosed.
In addition, a micelle solution for petroleum recovery containing an internal olefin sulfonate having 10 to 30 carbon atoms and an α-olefin sulfonate having 10 to 30 carbon atoms is disclosed (see Patent Document 4).

Also, stable crude oil recovery can be obtained with the Micellar Slag (petroleum product sulfonate, auxiliaries, a mixture of salt water and oil) and polymer injection, which is one of the conventional polymer flooding methods, and polymer injection. Also, a crude oil recovery agent comprising a nonionic surfactant comprising a reaction product of a fatty acid and an alkanolamine and an amide compound which is an alkylene oxide adduct thereof and a water-soluble polymer is proposed, and a high crude oil recovery rate is It is disclosed that it can be obtained stably. (See Patent Document 5).
Furthermore, a specific alkylxylene sulfonate has been proposed as a surfactant for EOR with low interfacial tension (see Patent Document 6).
And, as a method of improving the recovery of crude oil, gas and water from a hydrocarbon storage layer or oil well, 1 to 100 nm mixed in a wetting agent consisting of a carrier fluid of water or a hydrocarbon consisting of α-olefin sulfonate Patent Document 7 discloses a method of injecting nanoparticles of (for example, silicon dioxide etc.) into a hydrocarbon storage layer or oil well.

On the other hand, colloidal silica surface-treated with a silane coupling agent is disclosed, for example, as an anodic deposition type electrodeposition coating composition comprising an acrylic polycarboxylic acid resin neutralized with an amine or ammonium and a curing agent. (See Patent Document 8).

U.S. Pat. No. 3,506,070 U.S. Pat. No. 3,613,786 U.S. Pat. No. 3,740,343 Japanese Examined Patent Publication 1-35157 Tokuhei 5-86 989 Patent 5026264 specification US Patent Publication No. 2010/0096139 Patent 4033970 specification

In Patent Document 7, the separation pressure is increased by injecting nanoparticles mixed in a wetting agent composed of a carrier fluid of water or hydrocarbon into a hydrocarbon storage layer or oil well, and the oil adhering to the rock surface A method of efficiently tearing off drops has been disclosed. In order to further develop this effect, it is required that the nanoparticles be stable in the wetting agent, but for that purpose, the heat resistance of the wetting agent containing nanoparticles is required. In addition, in order to be effective in a hydrocarbon storage layer or oil well on the seabed, the salt resistance of the wetting agent containing nanoparticles is also required.

In order to improve the crude oil recovery of crude oil recovery chemicals, the presence of an anionic surfactant that has the effect of removing crude oil adhering to rocks such as sandstone or carbonate in the underground or marine oil reservoir is indispensable. However, the anionic surfactant is poor in high-temperature salt resistance, and when injected into a high-temperature high-salt oil layer, it decomposes in a short time, and the crude oil recovery effect can not be sufficiently exhibited. Colloidal silica is also said to have a crude oil recovery effect, but colloidal silica alone has poor high-temperature salt resistance, and it is also gelled in a short time when injected into a high-temperature, high-salt oil phase, and the crude oil recovery effect is sufficient Can not

For this reason, there is a demand for a crude oil recovery agent that contains an anionic surfactant and colloidal silica to simultaneously realize heat resistance and salt resistance and to realize efficient crude oil recovery.
In particular, crude oil recovery chemicals are often recovered several months after being injected into the underground or submarine oil reservoir. Stable even in unusually harsh environments exposed to seawater or salt water containing high concentrations of sodium ions, calcium ions and chloride ions, etc. under high temperature such as 100 ° C for several months, and crude oil There is a need for a drug that can exert its recovery effect.

The present invention is directed to a chemical solution used in surfactant flooding in EOR flooding in which crude oil is recovered by injecting it into the oil reservoir of inland or submarine oil field, that is, excellent in high temperature salt resistance. It is an object of the present invention to provide a crude oil recovery chemical solution having a high crude oil recovery rate.

As a result of intensive investigations by the present inventors to solve the above problems, in particular, silane compounds, aqueous silica sol having an average particle diameter of 3 to 200 nm, two or more types of anionic surfactants, and one or more types of nonionic surfactants It has been found that a chemical solution obtained by combining the above is used as a crude oil recovery chemical solution which is excellent in heat resistance and salt resistance and excellent in crude oil recovery.
In particular, by adjusting the crude oil recovery chemical solution of the present invention to a pH value of 2 or more and less than 7 and 12 or less, sodium chloride, magnesium chloride, sodium sulfate and calcium chloride are mainly added in addition to high temperature salt resistance to seawater. It has been found that it is a chemical solution for crude oil recovery that is excellent in high temperature salt resistance to artificial seawater as a component and is excellent in crude oil recovery.

That is, the present invention comprises, as a first aspect, a silane compound, an aqueous silica sol having an average particle diameter of 3 to 200 nm, two or more anionic surfactants, and one or more nonionic surfactants. The invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance, characterized by
As a second aspect, the high temperature salt resistance according to the first aspect, wherein the aqueous silica sol comprises silica particles formed by bonding at least a part of the silane compound to the surface of at least a part of the silica particles in the sol. Related to crude oil recovery chemicals.
As a third aspect, a silane having at least one organic functional group selected from the group consisting of vinyl, ether, epoxy, styryl, methacryl, acryl, amino and isocyanurate groups. The present invention relates to a chemical solution for crude oil recovery excellent in high-temperature salt resistance as described in the first aspect or the second aspect, which is at least one compound selected from the group consisting of a coupling agent, alkoxysilane, silazane and siloxane.
As a fourth aspect, the first aspect to the third aspect, wherein the aqueous silica sol is contained in 0.01% by mass to 30% by mass on a basis of the total mass of the crude oil recovery chemical solution in terms of solid content of silica. The present invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance described in any one of the viewpoints.
According to a fifth aspect, the silane compound is contained in a ratio such that the ratio of the mass of the silane compound to the mass of the solid silica component of the aqueous silica sol is 0.1 to 10.0. The present invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance described in any one of the four viewpoints.
As a sixth aspect, the anionic surfactant is sodium salt or potassium salt of fatty acid, alkyl benzene sulfonate, higher alcohol sulfate, polyoxyethylene alkyl ether sulfate, α-sulfo fatty acid ester, α-olefin sulfonic acid Selected from the group consisting of salts, monoalkyl phosphate esters and alkane sulfonates,
The present invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance as described in any one of the first to fifth aspects.
As a seventh aspect, any one of the first aspect to the sixth aspect, wherein the anionic surfactant is contained at 0.001% by mass to 20% by mass based on the total mass of the crude oil recovery chemical solution. The present invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance described in one paragraph.
As an eighth aspect, the anionic surfactant is contained at a ratio of 0.4 or more and less than 5.0 as a mass ratio with respect to the silica solid content of the chemical solution for recovering crude oil, and a chemical solution for recovering crude oil The chemical | medical solution for crude oil collection excellent in the high-temperature salt tolerance as described in any one of 1st viewpoint thru | or 7th viewpoint which has pH of 7 or more and less than 12.
As a ninth aspect, the anionic surfactant is contained at a ratio of 0.001 or more and less than 0.4 as a mass ratio with respect to the silica solid content of the chemical solution for crude oil recovery, and a chemical solution for crude oil recovery The chemical | medical solution for crude oil recovery as described in any one of 1st viewpoint thru | or 7th viewpoints which have pH of 2 or more and less than 7.
As a tenth aspect, the nonionic surfactant has an HLB value of 3.0 or more and 20.0 or less, and
It is selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, alkyl glucoside, polyoxyethylene fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester and fatty acid alkanolamide.
The present invention relates to a crude oil recovery chemical solution excellent in high-temperature salt resistance as described in any one of the first to ninth aspects.
According to an eleventh aspect, in the first to tenth aspects, the nonionic surfactant is contained in an amount of 0.001% by mass to 30% by mass based on the total mass of the crude oil recovery chemical solution. The present invention relates to a crude oil recovery chemical solution excellent in high temperature salt resistance.
According to a twelfth aspect of the present invention, there is provided a method of recovering crude oil from an underground hydrocarbon-containing bed,
(A) A crude oil recovery chemical solution containing a silane compound, an aqueous silica sol having an average particle diameter of 3 to 200 nm, two or more anionic surfactants, and one or more nonionic surfactants Press-in process,
(B) recovering crude oil from a production well by the chemical solution injected into the underground layer;
Related to the method.
As a thirteenth aspect, the crude oil recovery chemical solution is adjusted to a pH of 7 or more and less than 12, and the anionic surfactant is 0.4 or more as a mass ratio to the silica solids of the crude oil recovery chemical solution. The method according to the twelfth aspect, which is contained in an amount of less than 5.0.
As a fourteenth aspect, the crude oil recovery chemical solution is adjusted to a pH of 2 or more and less than 7, and the anionic surfactant is contained in a mass ratio of 0.001 or more to the silica solids of the crude oil recovery chemical solution. The method according to the twelfth aspect, which is contained in an amount of less than 0.4.

The chemical solution for crude oil recovery according to the present invention is excellent in high-temperature salt resistance, and does not cause problems such as gelation even when the chemical solution is diluted with seawater and injected into the oil reservoir of inland or submarine oil field. It is a stable chemical solution. Further, the chemical solution for crude oil recovery of the present invention is expected to improve the effect of removing crude oil from the rock surface not only by the crude oil peeling effect of the anionic surfactant but also by the wedge effect of the nanosilica particles contained in the chemical solution. It is a chemical for crude oil recovery that can recover crude oil with a high recovery rate.

The chemical solution for crude oil recovery of the present invention is characterized by containing a silane compound, an aqueous silica sol having an average particle diameter of 3 to 200 nm, two or more anionic surfactants, and one or more nonionic surfactants. I assume.
Each component will be described in detail below.

<PH of chemical solution>
The chemical | medical solution for crude oil recovery of this invention can select an optimal use by making the pH value into seven or more and less than 12 or making a pH value into two or more and less than 7. Specifically, a crude oil recovery chemical solution having a pH value of 7 or more and less than 12 is excellent under salt water containing chloride ion, sodium ion, calcium ion, magnesium ion and the like (for example, assumed use in inland underground oil reservoir) Show high temperature salt tolerance. Moreover, in addition to the salt solution containing chloride ion, sodium ion, calcium ion, magnesium ion etc., the chemical solution for crude oil recovery whose pH value is 2 or more and less than 7 is in seawater (for example, use in the submarine oil reservoir of submarine oil field is assumed) It also exhibits very good high temperature salt tolerance.
In addition, the chemical solution for crude oil recovery of the present invention may be adjusted to a pH value up to 12 using an aqueous alkali metal solution such as sodium hydroxide or potassium hydroxide, ammonia water, an aqueous solution of basic amine or the like. Excellent high temperature salt resistance can be obtained.
However, if the pH value of the crude oil recovery chemical solution is less than 2, the stability of the aqueous silica sol, the anionic surfactant, and the nonionic surfactant in the chemical solution may be deteriorated, which may cause gelation or decomposition. Not desirable. When the pH value of the chemical solution is more than 12, the magnesium ion in seawater or artificial seawater and the water-soluble strong alkali component in the chemical solution cause a neutralization reaction to generate poorly water-soluble magnesium hydroxide, and for crude oil recovery It is not preferable because it causes aggregation of the drug solution.

<Aqueous silica sol>
An aqueous silica sol refers to a colloidal dispersion system in which an aqueous solvent is used as a dispersion medium and colloidal silica particles are used as a dispersoid, and it can be manufactured by a known method using water glass (sodium silicate aqueous solution) as a raw material. The average particle size of the aqueous silica sol refers to the average particle size of colloidal silica particles which are dispersoids.

In the present invention, the average particle size of the aqueous silica sol (colloidal silica particles) refers to the specific surface area diameter or the particle size of the Sears method obtained by measurement by a nitrogen adsorption method (BET method) unless otherwise specified.
The specific surface area diameter (average particle diameter (specific surface area diameter) D (nm)) obtained by measurement by the nitrogen adsorption method (BET method) is from the specific surface area S (m ² / g) measured by the nitrogen adsorption method. It is given by the equation D (nm) = 2720 / S.
The particle size of the Sears method is as described in the literature: GW. Sears, Anal. Chem. 28 (12) p.1981, 1956 This is an average particle size measured based on a rapid measurement method of colloidal silica particle size. In particular, to determine the specific surface area of the colloidal silica from the amount of 0.1 N-NaOH was required to titrate the colloidal silica corresponding to SiO ₂ of 1.5g from pH4 to pH 9, equivalent size calculated therefrom (ratio Surface area diameter).
In the present invention, the average particle diameter of the aqueous silica sol (colloidal silica particles) according to the nitrogen adsorption method (BET method) or the shears method can be 3 to 200 nm, 3 to 150 nm, 3 to 100 nm, or 3 to 30 nm. .

And, by measuring the average particle size (DLS average particle size) by the dynamic light scattering method, the silica particles in the aqueous silica sol are in the dispersed state or in the aggregated state by measuring the average particle size (DLS average particle size) by the dynamic light scattering method. You can determine if there is.
The DLS average particle size represents the average value of secondary particle sizes (dispersed particle sizes), and the DLS average particle size in the state of being completely dispersed is an average particle size (nitrogen adsorption method (BET method) or Sears). It is said that the specific surface area diameter obtained by measurement according to the method is about twice as large as the average particle size of primary particles. And, it can be judged that the silica particles in the aqueous silica sol are in a state of aggregation as the DLS average particle diameter becomes larger.
For example, as an example of aqueous silica sol, aqueous silica sol manufactured by Nissan Chemical Industries, Ltd .: Snowtex (registered trademark) ST-O has an average particle diameter (BET method) of 10 to 11 nm and a DLS average particle diameter of 15 to It is 20 nm. In the examples to be described later, the high temperature salt resistance evaluation sample of the chemical for recovery of crude oil containing this aqueous silica sol has a DLS average particle diameter of 25 nm or less, and as a result, the silica particles are substantially dispersed in the chemical solution. Is shown.

When the high temperature salt resistance of the chemical solution is good, the DLS average particle size after the high temperature salt tolerance test is almost the same as the DLS average particle size of the chemical solution, for example, DLS average particle size after the high temperature salt tolerance test / DLS average particle of the chemical solution If the ratio of diameters is 1.1 or less, it indicates that the same dispersion state as the chemical solution is maintained even after the high temperature salt resistance test. However, when the high temperature salt resistance of the chemical solution is poor, the DLS particle diameter after the high temperature salt resistance test becomes very large, indicating a state of aggregation.
In the chemical solution for crude oil recovery of the present invention, if the ratio of DLS average particle diameter / average particle diameter of the chemical solution after the high temperature salt resistance test is 1.5 or less (the rate of change of average particle diameter is 50% or less) It can be judged that the ratio is 1.1 or less (the change rate is 10% or less) without deterioration of the silica sol, and it can be judged that the high temperature salt resistance is very good.

In the present invention, the average particle size of the aqueous silica sol is 3 to 200 nm, preferably 3 to 150 nm, more preferably 3 to 100 nm as measured by a nitrogen adsorption method (BET method) or a shears method. If the average particle size is smaller than 3 nm, the chemical solution becomes unstable, which is not preferable. On the other hand, when the average particle size is larger than 200 nm, the pores of sandstone or carbonate rock existing in the underground oil field formation are blocked, so that the oil recovery is unfavorably deteriorated.

The concentration of silica (SiO ₂ ) in the aqueous silica sol to be used is preferably 5 to 55% by mass.

In the present invention, commercially available aqueous silica sol can be used. Further, those having a silica concentration of 5 to 50% by mass in the aqueous silica sol are generally commercially available, and are preferable because they are easily available.
The aqueous silica sol can be used also for alkaline aqueous silica sol and acidic aqueous silica sol, but acidic aqueous silica sol is more preferable.

Commercially available acidic aqueous silica sols include Snowtex (registered trademark) ST-OXS, ST-OS, ST-O, ST-O-40, ST-OL, ST-OYL and ST-OZL. And -35 (all manufactured by Nissan Chemical Industries, Ltd.).

In the present invention, the aqueous silica sol is preferably contained in an amount of 0.01% by mass to 30.0% by mass based on the total mass of the crude oil recovery chemical solution in terms of solid content of silica, more preferably The content is 10.0% by mass to 25.0% by mass, for example, 15.0% by mass to 25.0% by mass.

As described later, in the crude oil recovery chemical solution of the present invention, at least a part of a silane compound described later may be bonded to the surface of a part of the silica particles in the aqueous silica sol.
The particle size of the silica particles in the aqueous silica sol in which the silane compound is bound to the surface can be easily measured by a commercially available apparatus as the aforementioned dynamic light scattering particle size.

<Silane compound>
The chemical solution for crude oil recovery of the present invention is characterized by containing a silane compound. By containing the silane compound, the high temperature salt resistance of the aqueous silica sol is greatly improved, so that the crude oil recovery effect is maintained.
As a silane compound, a silane coupling agent having at least one kind of group selected from the group consisting of vinyl group, ether group, epoxy group, styryl group, methacryl group, acrylic group, amino group and isocyanurate group as an organic functional group And alkoxysilanes, silazanes, siloxanes and the like other than those mentioned above can be mentioned as preferable silane compounds.

As the silane coupling agent having the above vinyl group or styryl group, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silanevinylmethyldimethoxysilane, vinyltriacetoxysilane, allyltrichlorosilane And allyltrimethoxysilane, allyltriethoxysilane, p-styryltrimethoxysilane and the like.
Examples of the silane coupling agent having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldi Ethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) propyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) propyltriethoxysilane, 2- (3,4-) Epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) methyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) methyltri Ethoxysilane [(3-ethyl-3-oxetanyl) methoxy] propyl trimethoxy silane, it includes [(3-ethyl-3-oxetanyl) methoxy] propyl triethoxysilane.
Examples of the silane coupling agent having a methacryl group (methacryloyl group) and an acryl group (acryloyl group) include 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, Examples thereof include 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane and the like.
As a silane coupling agent having the above amino group, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyl Trichlorosilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl) -Butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane and the like.
As the above-mentioned silane coupling agent having an isocyanurate group, tris- (3-trimethoxysilylpropyl) isocyanurate, tris- (3-triethoxysilylpropyl) isocyanurate, etc., and as an isocyanate group-containing silane coupling agent Examples include 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane and the like.

Also, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, ethyltrimethoxysilane, tetraethoxysilane, n-propyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane , Phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, n-propyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltrilesilane Alkoxysilanes such as ethoxysilane and n-decyltrimethoxysilane; silazanes such as hexamethyldisilazane; methyl methoxysiloxane Such a siloxane such as dimethyl phenylmethoxy siloxane may be used.

Among these silane compounds, an amphiphilic silane coupling agent having an ether group, an epoxy group, a methacryl group or an acrylic group is more preferable.
For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-) Epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyl Trimethoxysilane etc. are mentioned.

In the chemical solution for crude oil recovery of the present invention, the above silane compound is a silane compound / aqueous silica sol (silica: SiO ₂ ) = 0.1 to 10 by mass ratio to silica solid content in the aqueous silica sol, ie, silica particles. It is preferable to be added at a ratio of .0. More preferably, it is added at a ratio such that the same mass ratio is 0.1 to 5.0.
If the mass ratio of the silane compound to the silica particles in the aqueous silica sol is less than 0.1, the high temperature salt resistance of the chemical solution may be deteriorated, which is not preferable. Further, even if the same mass ratio is more than 10.0, that is, if a large amount of silane compound is added, no further improvement of the effect can be expected.
In the crude oil recovery chemical solution of the present invention, at least a part of the above-mentioned silane compound may be bonded to the surface of a part of the silica particles in the above-mentioned aqueous silica sol. The silica particles formed by bonding a silane compound to at least a part of the surface include, for example, silica particles whose surface is coated with a silane compound. By using a silica particle in which a silane compound is bonded to at least a part of the surface, for example, a silica particle whose surface is coated with a silane compound, the high temperature salt resistance of a chemical solution for crude oil recovery can be further improved.
Therefore, in a preferred embodiment, the crude oil recovery chemical solution of the present invention comprises silica particles in which the aqueous silica sol comprises at least a portion of the silane compound bonded to the surface of at least a portion of the silica particles in the sol. .

The silica particles (hereinafter also referred to as silica particles surface-treated with a silane compound) in which at least a part of the silane compound is bonded to at least a part of the surface are silica particles (silica solid content) in an aqueous silica sol. The silane compound is added to the aqueous silica sol at a ratio such that the mass ratio of the above-mentioned silane compound is 0.1 to 10.0, and then heat treated, for example, at 50 to 100 ° C. for 1 to 20 hours. You can get it.
At this time, it is preferable that the surface treatment amount with the above-mentioned silane compound, that is, the number of silane compounds bonded to the surface of the silica particle is, for example, about 0.1 to 12 per 1 nm ^{2 of the} silica particle surface.
When the heat treatment temperature is less than 50 ° C., the rate of partial hydrolysis is slowed and the efficiency of surface treatment is deteriorated.
Further, if the heat treatment time is less than 1 hour, the partial hydrolysis reaction of the silane compound is insufficient, and even if it is longer than 20 hours, the partial hydrolysis reaction of the silane compound is almost saturated. It does not have to be long.

<Anionic surfactant>
In the crude oil recovery chemical solution of the present invention, two or more kinds of anionic surfactants are used. For example, 2 to 5 anionic surfactants, or 2 to 4 anionic surfactants, or 2 to 3 anionic surfactants, or 2 anionic surfactants can be combined.
In the present invention, by using a drug solution containing two or more types of anionic surfactants rather than a drug solution containing only one type of anionic surfactant, the surfactants mutually enter each other to form a more compact micelle. By forming (packing effect), a more preferable effect of stabilizing the surfactant itself can be obtained. As a result, the anionic surfactant becomes stable, and the crude oil recovery effect is maintained. The chemical solution of the present invention is intended to stabilize the chemical solution which is expected to be used under high temperature brine such as crude oil recovery by utilizing the packing effect by blending a plurality of surfactants, and such packing under high temperature brine The use of effects is an unprecedented idea.

As an anionic surfactant, sodium salt and potassium salt of fatty acid, alkylbenzene sulfonate, higher alcohol sulfate, polyoxyethylene alkyl ether sulfate, α-sulfo fatty acid ester, α-olefin sulfonate, monoalkyl phosphorus Acid ester salts and alkane sulfonates can be mentioned.

For example, alkyl benzene sulfonates include sodium salts, potassium salts and lithium salts, and there are sodium C10 to C16 alkyl benzene sulfonates, C10 to C16 alkyl benzene sulfonic acids, sodium alkyl naphthalene sulfonates and the like.
Examples of higher alcohol sulfate ester salts include sodium dodecyl sulfate having 12 carbon atoms (sodium lauryl sulfate), triethanolamine lauryl sulfate, triethanolammonium lauryl sulfate and the like.
The polyoxyethylene alkyl ether sulfate is sodium polyoxyethylene styrenated phenyl ether sulfate, polyoxyethylene styrenated phenyl ether ammonium sulfate, polyoxyethylene decyl ether sodium sulfate, polyoxyethylene decyl ether ammonium sulfate, polyoxyethylene lauryl ether sodium sulfate And polyoxyethylene lauryl ether ammonium sulfate, polyoxyethylene tridecyl ether sodium sulfate, and polyoxyethylene oleyl cetyl ether sodium sulfate.
Examples of α-olefin sulfonates include sodium α-olefin sulfonates.
Examples of alkane sulfonates include sodium 2-ethylhexyl sulfate.

Among them, it is preferable to use an α-olefin sulfonate and a higher alcohol sulfate in combination as an anionic surfactant. In this case, the blending ratio of the α-olefin sulfonate and the higher alcohol sulfate is not particularly limited. For example, in molar ratio, α-olefin sulfonate: higher alcohol sulfate = 5: 1 to 1: 5 For example, 3: 1 to 1: 3, 1: 2 to 1: 3, 1: 1 to 1: 2, and the like.
The anionic surfactant is preferably contained in a total amount of 0.001% by mass to 20% by mass, based on the total mass in the crude oil recovery chemical solution. If the amount is less than 0.001% by mass, it is not preferable because the high-temperature salt resistance and the crude oil recovery ability of the chemical solution deteriorate. When the content is more than 20% by mass, emulsification of the recovered oil and surfactant is severe, and separation of the oil and surfactant becomes difficult, which is not preferable.

As described above, the chemical solution for crude oil recovery of the present invention can select an optimum application depending on whether the pH value is 7 or more and less than 12 or the pH value is 2 or more and less than 7. At this time, by adjusting the amount of the anionic surfactant, it is possible to make the chemical solution more excellent in high-temperature salt resistance.
For example, when the chemical solution for crude oil recovery is adjusted to a pH of 7 or more and less than 12, the anionic surfactant may have a mass ratio of 0.4 to less than 5.0 with respect to the silica solid content of the chemical for recovery of crude oil. Preferably, it is contained in an amount of
Further, when the crude oil recovery chemical solution is adjusted to a pH of 2 or more and less than 7, the anionic surfactant may have a mass ratio of 0.001 or more and less than 0.4 with respect to the silica solid content of the crude oil recovery chemical solution. Preferably, it is contained in an amount of

<Nonionic surfactant>
In the chemical solution for crude oil recovery of the present invention, in addition to the above two anionic surfactants, one or more nonionic surfactants are used. For example, 1 to 5 non-ionic surfactants, or 1 to 4 non-ionic surfactants, or 1 to 3 non-ionic surfactants, or a combination of 1 to 2 non-ionic surfactants Or one non-ionic surfactant can be used.

In the present invention, by using a chemical solution containing both an anionic surfactant and a nonionic surfactant, the anionic surfactant and the nonionic surfactant enter each other, and only two or more anionic surfactants are contained. By forming a more compact micelle, the more preferable effect of stabilizing the surfactant itself can be obtained. As a result, the anionic surfactant and the nonionic surfactant become stable, and the crude oil recovery effect is maintained.

In the present invention, nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, alkyl glucoside, polyoxyethylene fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanol It is selected from amides.

For example, as polyoxyethylene alkyl ether, polyoxyethylene dodecyl ether (polyoxyethylene lauryl ether), polyoxyalkylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene myristyl ether, poly Examples thereof include oxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyoxyethylene 2-ethylhexyl ether, and polyoxyethylene isodecyl ether.
Examples of the polyoxyethylene alkylphenol ether include polyoxyethylene styrenated phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene distynylated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.
Examples of alkyl glucosides include decyl glucoside and lauryl glucoside.
Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol diolate, polypropylene glycol diolate and the like.
As sorbitan fatty acid esters, sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan Monosesquiolates and their ethylene oxide adducts.
As polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxy acid There are ethylene sorbitan trioleate, polyoxyethylene sorbitan triisostearate and the like.
Examples of fatty acid alkanolamides include coconut oil fatty acid diethanolamide, beef tallow fatty acid diethanolamide, lauric acid diethanolamide, oleic acid diethanolamide and the like.
Furthermore, polyoxyethylene polyoxypropylene glycol, polyoxyalkyl ether such as polyoxyethylene fatty acid ester or polyoxyalkyl glycol, polyoxyethylene hydrogenated castor oil ether, sorbitan fatty acid ester alkyl ether, alkyl polyglucoside, sorbitan monooleate, Sugar fatty acid esters can also be used.
Among the nonionic surfactants, polyoxyethylene alkyl ether and polyoxyethylene alkyl phenol ether are more preferable because they have good high-temperature salt resistance of the drug solution.

The HLB value of the nonionic surfactant is a numerical value representing the balance between hydrophobicity and hydrophilicity, and a substance having no hydrophilic group is HLB = 0, and a substance having no hydrophobic group and having only a hydrophilic group is HLB = 20. .
In the present invention, as the nonionic surfactant, one having an HLB value of 3.0 or more and 20.0 or less is preferably used. It is more preferable to use a nonionic surfactant having an HLB value of 10.0 or more and 20.0 or less from the viewpoint of the high temperature salt resistance of the chemical solution. Furthermore, from the viewpoint of human safety and environmental safety, there are no harmful effects on the aquatic environment for a long time, so there is no concern about so-called environmental hormones, and nonionic surfactants with an HLB value of 14.0 or more and 20.0 or less are used. It is more preferable to do. In addition, when using two or more kinds of nonionic surfactants having different HLB values, the HLB value of the mixture determined from the weight average of the HLB value and the blending ratio is adjusted to be 10.0 or more and 20.0 or less. It is preferable to do.
When the HLB value is less than 3.0, the hydrophobicity of the non-ionic surfactant is strong, so that the aqueous silica sol and the water-soluble anionic surfactant and the non-ionic surfactant are not mixed in the prepared chemical solution, and the two layers are mixed. Not desirable because of separation.

The nonionic surfactant is preferably contained in an amount of 0.001% by mass to 30% by mass, based on the total mass in the chemical solution for crude oil recovery. If the amount is less than 0.001% by mass, the heat resistance and the salt resistance of the chemical solution deteriorate, which is not preferable. When the content is more than 30% by mass, the viscosity of the chemical solution becomes very high, which is not preferable.
In addition, even if it is a chemical solution containing only one type of nonionic surfactant or a chemical solution containing 2 or more and 5 or less types of nonionic surfactants, excellent high-temperature salt resistance can be obtained, and a good crude oil recovery ability can be obtained.

<Other ingredients>
Water-soluble polymers such as hydroxyethyl cellulose and its salts, hydroxypropyl methylcellulose and its salts, carboxymethyl cellulose and its salts, pectin, guar gum xanthan gum, damarind gum, carrageenan etc. can be further added to increase the viscosity of the drug solution. .

The chemical solution for crude oil recovery according to the present invention is a combination of an aqueous silica sol and a silane compound, in particular, silica obtained by combining at least a part of the silane compound on at least a part of the surface as silica particles in the aqueous silica sol. By including the particles, it is considered that the compatibility between the silica particles in the aqueous silica sol and the surfactant is improved. Furthermore, by combining two or more types of anionic surfactants and one or more types of nonionic surfactants, the surfactants mutually enter each other to form a more compact micelle and stabilize the surfactant itself. Therefore, it is considered that it becomes a chemical solution for crude oil recovery excellent in high temperature salt resistance.

The procedure for recovering crude oil from the underground hydrocarbon-containing layer using the crude oil recovery chemical solution of the present invention includes, for example, (a) injecting the crude oil recovery chemical solution of the present invention into the underground layer; (B) It can be implemented including the process of recovering crude oil from a production well with the above-mentioned chemical liquid injected into the underground layer.
At this time, the chemical solution for crude oil recovery is adjusted to a pH of 7 to less than 12, and the anionic surfactant is 0.4 to 5.0 as a mass ratio to the silica solid content of the chemical solution for crude oil recovery. When the chemical solution for crude oil recovery is adjusted to a pH of 2 or more and less than 7 or less, the anionic surfactant is used relative to the solid content of silica in the chemical solution for crude oil recovery, By containing it in an amount of 0.001 or more and less than 0.4 as a mass ratio, it becomes a chemical solution for crude oil recovery which is more excellent in high-temperature salt resistance, and thus a higher crude oil recovery ability can be expected.

Hereinafter, the present invention will be described in more detail based on Synthesis Examples, Examples, Comparative Examples and Reference Examples, but the present invention is not limited to these Examples.

(measuring device)
Analysis (pH value, electric conductivity, DLS average particle size) of the aqueous silica sol prepared in the synthesis example, and analysis of the chemical solution manufactured in Examples and Comparative Examples (pH value, electric conductivity, viscosity, DLS average particle Diameter), analysis of the sample after the high temperature salt resistance test of the sample prepared using the said chemical | medical solution was performed using the following apparatuses.
-DLS average particle size (dynamic light scattering particle size): A dynamic light scattering particle size measuring apparatus Zeta Sizer Nano (manufactured by Spectris Co., Ltd., Malvern Division) was used.
PH: A pH meter (manufactured by Toho DKK Co., Ltd.) was used.
Electrical conductivity: An electrical conductivity meter (manufactured by Toho DK Co., Ltd.) was used.
Viscosity: A B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.) was used.
Surface tension: A surface tension meter DY-500 (manufactured by Kyowa Interface Chemical Co., Ltd.) was used.

[Evaluation of crude oil recovery chemicals]
(High temperature salt resistance evaluation)
(High temperature salt resistance evaluation-1)
A stirrer is charged into a 200 ml polystyrene bottle, 50 g of each chemical solution prepared in the example or comparative example is charged, and a salt solution having a salt concentration of 6 mass% (sodium chloride concentration 4.8 mass%) while stirring with a magnetic stirrer The solution was charged with 100 g of calcium chloride (1.2 mass%) and stirred for 1 hour. This was taken as a brine test sample (a) for evaluating the heat resistance and salt resistance of the chemical solution under a salt concentration of 4% by mass.
In a 120 ml Teflon (registered trademark) sealable container, put 65 g of brine test sample (a), and after sealing, place the Teflon (registered trademark) container in a dryer at 100 ° C. and maintain it at 100 ° C. for a predetermined time The appearance, pH, electric conductivity, viscosity of the brine test sample (a), and the DLS average particle size of the aqueous silica sol (silica particles) in the sample were evaluated.
The determination of the high-temperature salt resistance was as follows based on the measurement results of the DLS average particle diameter of the aqueous silica sol (silica particles) in the sample and the evaluation of the appearance after holding for a predetermined time under high temperature.
Determination of high temperature salt tolerance
A: The ratio of DLS average particle diameter / DLS average particle diameter of chemical solution after high temperature salt resistance test is 1.1 or less, there is no deterioration of silica sol, and high temperature salt resistance is very good B: after high temperature salt resistance test The ratio of DLS average particle diameter / DLS average particle diameter of chemical solution is 1.2 to 1.5, high temperature salt resistance is good,
C: DLS average particle size after high temperature salt resistance test / DLS average particle size ratio of chemical solution is 1.6 to 8.0, high temperature salt resistance ordinary D: DLS average particle size after high temperature salt resistance test / chemical solution The ratio of DLS average particle diameter is 8.1 to 20.0 and the high temperature salt resistance is poor E: DLS average particle diameter after high temperature salt resistance test / DLS average particle diameter ratio of chemical solution is 20.1 or more Or those that could not be measured for DLS particle size due to gelation of silica sol and formation of white precipitates, high temperature salt resistance very bad

(High temperature salt resistance evaluation -2)
A stirrer is charged into a 200 ml polystyrene bottle, 50 g of each chemical solution prepared in the example or comparative example is charged, and a salt solution having a salt concentration of 15 mass% (sodium chloride concentration 12.0 mass%) while stirring with a magnetic stirrer , 100 mass% of calcium chloride concentration) was added, and stirred for 1 hour. The heat resistance and salt resistance of the chemical solution under a 10% by mass salt concentration consisting of 8% by mass sodium chloride and 2% by mass calcium chloride defined by API standards (a standard for petroleum established by the American Petroleum Institute). It was set as the brine test sample (b) which evaluates sex.
The high temperature salt resistance was judged by the same operation as the above (high temperature salt resistance evaluation-1).

(High temperature salt resistance evaluation -3)
After 2408 g of pure water was placed in a 3 L polyethylene container, 92 g of artificial seawater powder (trade name: Marin Art SF-1 manufactured by Tomita Pharmaceutical Co., Ltd.) was charged to prepare artificial seawater. A stirrer is placed in a 200 ml polystyrene bottle, and each chemical solution, pure water and artificial seawater prepared in the example are added while stirring with a magnetic stirrer to prepare 150 g of a mixed solution with a silica concentration of 1.0 mass%, Stir for 1 hour. This was used as a seawater test sample to evaluate the heat resistance and salt tolerance of the chemical solution in artificial seawater.
The high temperature salt resistance was judged by the same operation as the above (high temperature salt resistance evaluation-1).

(High temperature salt resistance evaluation-4)
After 2408 g of pure water was placed in a 3 L polyethylene container, 92 g of artificial seawater powder (trade name: Marin Art SF-1 manufactured by Tomita Pharmaceutical Co., Ltd.) was charged to prepare artificial seawater. A stirrer is placed in a 200 ml polystyrene bottle, and each chemical solution, pure water and artificial seawater prepared in the example are added while stirring with a magnetic stirrer to prepare 150 g of a mixed solution with a silica concentration of 0.5 mass%, Stir for 1 hour. This was used as a seawater test sample to evaluate the heat resistance and salt tolerance of the chemical solution in artificial seawater.
The high temperature salt resistance was judged by the same operation as the above (high temperature salt resistance evaluation-1).

[Preparation of chemical solution for crude oil recovery: Preparation of aqueous sol]
Synthesis Example 1
In a 500 ml glass-made eggplant flask, aqueous silica sol (Snowtex (registered trademark) ST-O, manufactured by Nissan Chemical Industries, Ltd., silica concentration = 20.5 mass%, BET method average particle diameter 11.0 nm, DLS average particle diameter 17.3. After adding 200 g of a magnetic stirrer and 2 g of a magnetic stirrer, stirring with a magnetic stirrer, 3-glycidoxypropyltrimethoxysilane (a mass ratio of the silane compound to that of silica in the aqueous silica sol is 0.09). 4.0 g of Evonik Dynasylan GLYMO was introduced. Subsequently, a cooling pipe in which tap water was allowed to flow was installed at the top of the eggplant flask, the temperature of the aqueous sol was raised to 60 ° C. while refluxing, and maintained at 60 ° C. for 3 hours. After cooling to room temperature, the aqueous sol was taken out.
Silane having a mass ratio of silane compound to silica in aqueous silica sol of 0.09, silica solid content = 20.2 mass%, pH = 3.1, electric conductivity = 452 μS / cm, DLS average particle diameter = 24.3 nm 204 g of an aqueous sol containing an aqueous silica sol surface-treated with a compound was obtained.

(Composition example 2)
Aqueous silica sol (Snowtex (registered trademark) ST-O, manufactured by Nissan Chemical Industries, Ltd., silica concentration = 20.5 mass%, BET method average particle diameter 11.0 nm, DLS average particle diameter 17.2 nm) The aqueous sol was prepared in the same manner as in Synthesis Example 1 except that 7.9 g of 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO manufactured by Evonik Co., Ltd.) was added such that the mass ratio of the silane compound was 0.20. Obtained.
Silane having a weight ratio of silane compound to silica in aqueous silica sol of 0.2, solid content of silica = 20.6% by mass, pH = 2.9, electric conductivity = 544 μS / cm, DLS average particle diameter = 19.5 nm 208 g of an aqueous sol containing an aqueous silica sol surface-treated with a compound was obtained.

(Composition example 3)
Aqueous silica sol (Snowtex (registered trademark) ST-O, manufactured by Nissan Chemical Industries, Ltd., silica concentration = 20.5 mass%, BET method average particle diameter 11.0 nm, DLS average particle diameter 17.2 nm) The aqueous sol was prepared in the same manner as in Synthesis Example 1 except that 15.8 g of 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO manufactured by Evonik Co., Ltd.) was added such that the mass ratio of the silane compound was 0.40. Obtained.
Silane having a weight ratio of silane compound to silica in aqueous silica sol of 0.4, silica solid content = 20.5 mass%, pH = 2.9, electric conductivity = 474 μS / cm, DLS average particle diameter = 19.7 nm 216 g of an aqueous sol containing an aqueous silica sol surface-treated with the compound was obtained.

(Composition example 4)
Aqueous silica sol (Snowtex (registered trademark) ST-O, manufactured by Nissan Chemical Industries, Ltd., silica concentration = 20.5 mass%, BET method average particle diameter 11.0 nm, DLS average particle diameter 17.2 nm) The aqueous sol was prepared in the same manner as in Synthesis Example 1 except that 31.6 g of 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO manufactured by Evonik Co., Ltd.) was added such that the mass ratio of the silane compound was 0.80. Obtained.
Silane having a weight ratio of silane compound to silica in aqueous silica sol of 0.8, solid content of silica = 10.6% by mass, pH = 2.8, electric conductivity = 413 μS / cm, DLS average particle diameter = 20.8 nm 231 g of an aqueous silica sol surface-treated with the compound was obtained.

(Composition example 5)
Aqueous silica sol (Snowtex (registered trademark) ST-OXS manufactured by Nissan Chemical Industries, Ltd., silica concentration = 10.4% by mass, Sears method average particle diameter 5.0 nm, DLS average particle diameter = 8) .3 nm) 3-glycidoxypropyltrimethoxy so that the mass ratio of the silane compound is 3.4 to the silica in the aqueous silica sol while stirring with a magnet stirrer after 250 g of the magnet stirrer and a magnet stirrer. 88.9 g of silane (Evonik Dynasylan GLYMO) was charged. Subsequently, a cooling pipe in which tap water was allowed to flow was installed at the top of the eggplant flask, the temperature of the aqueous sol was raised to 60 ° C. while refluxing, and maintained at 60 ° C. for 3 hours. After cooling to room temperature, the aqueous sol was taken out.
Silane compound with a mass ratio of silane compound to silica in aqueous silica sol 3.4, silica solid content = 14.3 mass%, pH = 2.9, conductivity = 163 μS / cm, DLS average particle size 8.1 nm 338 g of a surface-treated aqueous silica sol was obtained.

Synthesis Example 6
Aqueous silica sol (Snowtex (registered trademark) ST-OL manufactured by Nissan Chemical Industries, Ltd., silica concentration = 20.0 mass%, BET method average particle diameter 46 nm, DLS average particle diameter = 75.8 nm) After charging 200 g of the magnetic stirrer and then stirring with a magnetic stirrer, 3-glycidoxypropyltrimethoxysilane (the mass ratio of the silane compound is 1.6 with respect to the silica in the aqueous silica sol). An aqueous sol was obtained in the same manner as in Synthesis Example 1 except that 31.9 g of Evonik Dynasylan GLYMO was charged.
Mass ratio of silane compound to silica in aqueous silica sol = 0.8, solid content of silica = 21.2 mass%, pH = 3.1, electric conductivity = 160 μS / cm, DLS average particle diameter = 76.4 nm, 231 g of an aqueous silica sol surface-treated with a silane compound was obtained.

Synthesis Example 7
Aqueous silica sol (Snowtex® ST-OZL-35, manufactured by Nissan Chemical Industries, Ltd., silica concentration = 35.7 mass%, BET method average particle diameter 83 nm, DLS average particle diameter 126 nm) After charging 115 g of pure water and 85 g of pure water with a magnet stirrer, while stirring with a magnet stirrer, 3-glycidoxypropyl tri such that the mass ratio of silane compound to silica in aqueous silica sol is 0.8. An aqueous sol was obtained in the same manner as in Synthesis Example 1 except that 32.8 g of methoxysilane (Dynasylan GLYMO manufactured by Evonik Co., Ltd.) was added.
Mass ratio of silane compound to silica in aqueous silica sol 1,6, solid content of silica = 20.7% by mass, pH = 2.6, electric conductivity = 579 μS / cm, DLS average particle diameter = 119 nm, surface with silane compound 232 g of treated aqueous silica sol are obtained.

[Preparation of chemical solution for crude oil recovery]
Example 1
A stirrer was placed in a 300 ml polystyrene bottle, and 91.0 g of pure water was charged. While stirring with a magnetic stirrer, 2.3 g of the anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was charged, and stirred until completely dissolved. Subsequently, 4.7 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 2 was added, and subsequently, polyoxyethylene nonylphenyl ether of HLB = 13.0 (non-ionic surfactant) (Reagent Tergitol (registered trademark) NP-9 manufactured by Sigma) After charging 30.0 g, the solution was stirred for 1 hour to produce the drug solution of Example 1.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 2)
The input amount of pure water is 106.0 g, and the input amount of polyoxyethylene nonyl phenyl ether with HLB = 13.0 as a nonionic surfactant (reagent for sigma, Tergitol (registered trademark) NP-9) 15.0 g The drug solution of Example 2 was manufactured in the same operation as Example 1 except that
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 3)
The input amount of pure water is 113.5 g, and the input amount of polyoxyethylene nonylphenyl ether with HLB = 13.0 as a non-ionic surfactant (reagent for Tergitol (registered trademark) NP-9 manufactured by Sigma) 7.5 g The drug solution of Example 3 was manufactured in the same operation as Example 1 except that
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 4)
A polyoxyethylene styrenated phenyl ether (Nichigen (registered trademark) EA-137 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) of HLB = 13.0 was adopted as a non-ionic surfactant, and the amount of addition was 15.0 g. The chemical solution of Example 4 was manufactured by the same operation as Example 2 except for the above.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 5)
Pure water input amount is 99.6 g, and polyoxyethylene styrenated phenyl ether (Daigen Kogyo Seiyaku Co., Ltd. Neugen (registered trademark) EA-157) of HLB = 14.3 is used as a non-ionic surfactant A drug solution of Example 5 was produced in the same manner as Example 2, except that 21.4 g of the diluted active ingredient 70% diluted with water was charged.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 6)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.5 g of pure water was charged. While stirring with a magnetic stirrer, 1.8 g of an anionic surfactant sodium α-olefin sulfonate (Neogen (registered trademark) AO-90 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added and stirred until completely dissolved. Subsequently, 5.3 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 2 was added, and subsequently, polyoxyethylene styrenated phenyl ether of HLB = 14.3 (non-ionic surfactant, Neugen (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Neugen (registered 21.4 g of a solution obtained by diluting trade mark EA-157) with pure water to make the active ingredient 70% was charged, and then stirred for 1 hour to produce a drug solution of Example 6.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 7)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 3 was added, and subsequently, polyoxyethylene styrenated phenyl ether of HLB = 14.3 (non-ionic surfactant, Neugen (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Neugen (registered 21.4 g of a solution obtained by diluting EA (trademark) EA-157) with pure water to make the active ingredient 70% was added, and stirred for 1 hour to produce a drug solution of Example 7.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 8)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 3 was added, and subsequently, polyoxyethylene styrenated phenyl ether of HLB = 14.3 (non-ionic surfactant, Neugen (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Neugen (registered 21.4 g of a solution obtained by diluting EA (trademark) EA-157) with pure water to make the active ingredient 70% was added, and stirred for 1 hour to produce a drug solution of Example 8.
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 9)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 was added, and subsequently, polyoxyethylene styrenated phenyl ether with HLB = 14.3 as a nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd. 21.4 g of a product obtained by diluting Neugen (registered trademark) EA-157 manufactured by Co., Ltd. with pure water to make the active ingredient 70% was charged, and then stirred for 1 hour to produce a drug solution of Example 9.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 10)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 22.0 g of an aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 3 was added, and subsequently polyoxyethylene tridecyl ether of HLB = 13.6 as a nonionic surfactant (Daiichi Kogyo Seiyaku Co. After adding 15.2 g of Neugen (registered trademark) TDS-90, manufactured by Co., Ltd., the solution was stirred for 1 hour to produce a drug solution of Example 10.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 30 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 11)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 was added, and subsequently, polyoxyethylene styrenated phenyl ether with HLB = 14.3 as a nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd. 21.4 g of a product obtained by diluting Neugen (registered trademark) EA-157 manufactured by Co., Ltd. with pure water to make the active ingredient 70% was charged, and then stirred for 1 hour to produce a drug solution of Example 11.
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 12)
A stirrer was placed in a 300 ml polystyrene bottle, and 48.8 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 72.8 g of the aqueous silica sol surface-treated with the silane compound prepared in Synthesis Example 4 was charged, and subsequently, polyoxyethylene styrenated phenyl ether with HLB = 14.3 as a nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd. 21.4 g of a product obtained by diluting Neugen (registered trademark) EA-157 manufactured by Co., Ltd. with pure water to make the active ingredient 70% was charged, and then stirred for 1 hour to produce a drug solution of Example 12.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 13)
A stirrer was placed in a 300 ml polystyrene bottle, and 6.4 g of pure water and 131.1 g of an aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 were charged and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 3.5 g of an anionic surfactant sodium α-olefin sulfonate (Lipan Specialty Chemicals KK Lipoan (registered trademark) LB-440 active ingredient 36.3%) Charged and stirred. Subsequently, 1.3 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved. Then, as a nonionic surfactant, HLB = 14.3 polyoxyethylene styrenated phenyl ether (Daigen Kogyo Co., Ltd. Neugen (registered trademark) EA-157) is diluted with pure water and the active ingredient is 70% After charging 7.7 g of the solution, the solution was stirred for 1 hour to produce the drug solution of Example 13.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 14)
A stirrer was placed in a 300 ml styrene bottle, and 14.7 g of pure water and 131.1 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 were charged, and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 1.2 g of an anionic surfactant sodium α-olefin sulfonate (Lion Specialty Chemicals Ltd. Lipoan (registered trademark) LB-440 active ingredient 36.3%) 1.2 g Charged and stirred. Subsequently, 0.45 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved. Then, as a nonionic surfactant, HLB = 14.3 polyoxyethylene styrenated phenyl ether (Daigen Kogyo Co., Ltd. Neugen (registered trademark) EA-157) is diluted with pure water and the active ingredient is 70% The solution was stirred for 1 hour to produce a drug solution of Example 14.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 15)
A stirrer was placed in a 300 ml polystyrene bottle, and 15.5 g of pure water and 131.1 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 were charged, and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 1.2 g of an anionic surfactant sodium α-olefin sulfonate (Lion Specialty Chemicals Ltd. Lipoan (registered trademark) LB-440 active ingredient 36.3%) 1.2 g Charged and stirred. Subsequently, 0.45 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved. Subsequently, 1.8 g of polyoxyethylene styrenated phenyl ether with HLB = 11.7 (Nuygen (registered trademark) EA-127 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a nonionic surfactant was added and then stirred for 1 hour The chemical solution of Example 15 was produced.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 16)
A stirrer was placed in a 300 ml polystyrene bottle, and 14.0 g of pure water and 131.1 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 were charged, and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 1.2 g of an anionic surfactant sodium α-olefin sulfonate (Lion Specialty Chemicals Ltd. Lipoan (registered trademark) LB-440 active ingredient 36.3%) 1.2 g Charged and stirred. Subsequently, 0.45 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved. Subsequently, 3.3 g of polyoxyethylene styrenated phenyl ether having HLB = 18.7 (Nuygen (registered trademark) EA-207D manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., 55% active ingredient) was added as a nonionic surfactant Thereafter, the solution was stirred for 1 hour to produce a drug solution of Example 16.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and held at 100 ° C. for 60 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 17)
A stirrer was placed in a 300 ml polystyrene bottle, and 90.1 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved.
Subsequently, 31.5 g of the aqueous silica sol produced in Synthesis Example 5 was charged, and subsequently, polyoxyethylene styrenated phenyl ether (HLN = 14.3, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Neugen (registered trademark) as a nonionic surfactant). After 21.4 g of (trademark) EA-157) was added, the solution was stirred for 1 hour to produce a drug solution of Example 17.
After preparing a brine test sample (a) according to the high temperature salt resistance evaluation-1 and holding it at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Example 18)
A stirrer was placed in a 300 ml styrene bottle, and 18.4 g of pure water and 127.4 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 6 were charged and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 1.2 g of an anionic surfactant sodium α-olefin sulfonate (Lion Specialty Chemicals Ltd. Lipoan (registered trademark) LB-440 active ingredient 36.3%) 1.2 g Charged and stirred. Subsequently, 0.45 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added and stirred until completely dissolved. Then, as a nonionic surfactant, HLB = 14.3 polyoxyethylene styrenated phenyl ether (Daigen Kogyo Co., Ltd. Neugen (registered trademark) EA-157) is diluted with pure water and the active ingredient is 70% The solution was stirred for 1 hour to produce a drug solution of Example 18.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and kept at 100 ° C. for 30 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

(Example 19)
A stirrer was placed in a 300 ml polystyrene bottle, and 15.3 g of pure water and 130.5 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 7 were charged and stirred with a magnetic stirrer. Subsequently, while stirring with a magnetic stirrer, 1.2 g of an anionic surfactant sodium α-olefin sulfonate (Lion Specialty Chemicals Ltd. Lipoan (registered trademark) LB-440 active ingredient 36.3%) 1.2 g Charged and stirred. Subsequently, 0.4 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Rika Co., Ltd.) was added and stirred until completely dissolved. Then, as a nonionic surfactant, HLB = 14.3 polyoxyethylene styrenated phenyl ether (Daigen Kogyo Co., Ltd. Neugen (registered trademark) EA-157) is diluted with pure water and the active ingredient is 70% The solution was stirred for 1 hour to produce a drug solution of Example 19.
A seawater test sample was prepared according to the high temperature salt resistance evaluation-3 and kept at 100 ° C. for 30 hours, then the sample was taken out and the high temperature salt resistance was evaluated.

Example 20
The drug solution of Example 20 was produced in the same manner as in Example 13.
After preparing a seawater test sample according to the high temperature salt resistance evaluation-4 and holding it at 100 ° C. for 75 days (1800 hours), the sample was taken out and the high temperature salt resistance was evaluated.

(Example 21)
The chemical solution of Example 21 was manufactured in the same manner as in Example 14.
After preparing a seawater test sample according to the high temperature salt resistance evaluation-4 and holding it at 100 ° C. for 75 days (1800 hours), the sample was taken out and the high temperature salt resistance was evaluated.

(Example 1)
The same operation as in Example 1 is carried out in the same manner as in Example 1 except that 22.0 g of aqueous silica sol (Snowtex (registered trademark) ST-O manufactured by Nissan Chemical Industries, Ltd.) is charged instead of the aqueous silica sol produced in Synthesis Example 2. A chemical solution was produced (without containing a silane compound).
A brine test sample (a) was prepared according to High Temperature Salt Tolerance Evaluation-1 and after keeping for 7 days at room temperature, the sample was removed and the salt tolerance was evaluated.

(Example 2)
The drug solution of Example 2 was produced by the same operation as Example 1 except that 22.0 g of the aqueous silica sol produced in Synthesis Example 1 was charged instead of the aqueous silica sol produced in Synthesis Example 2 (mass of silane compound relative to silica Ratio: 0.09).
A brine test sample (a) was prepared according to High Temperature Salt Tolerance Evaluation-1 and after keeping for 7 days at room temperature, the sample was removed and the salt tolerance was evaluated.

(Example 3)
An example was carried out in the same manner as in Example 1, except that the amount of non-ionic surfactant HLB = 13.0 polyoxyethylene nonylphenyl ether (Sigma Tergitol (registered trademark) NP-9) was changed to 0 g. A drug solution of 3 was produced (without containing a nonionic surfactant).
A brine test sample (a) was prepared according to the high temperature salt resistance evaluation-1, but immediately after preparation, it became cloudy and a white gel precipitated.

(Example 4)
A polyoxyethylene styrenated phenyl ether (Nichigen (registered trademark) EA-017 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) of HLB = 2.7 was adopted as a non-ionic surfactant, and the amount of addition was 15.0 g. Example 4 was manufactured in the same operation as Example 4 (except that the HLB value of the nonionic surfactant is low) except for the above.
The prepared drug solution was completely separated into two layers from an aqueous phase consisting of an aqueous silica sol and a water-soluble anionic surfactant and an oil phase consisting of a nonionic surfactant. For this reason, high temperature salt tolerance could not be evaluated.

(Comparative example 1)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 6.8 g of the anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was charged, and stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 3 was added, and subsequently, polyoxyethylene styrenated phenyl ether of HLB = 14.3 (non-ionic surfactant, Neugen (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Neugen (registered (Trademark) EA-157) was diluted with pure water to give 21.4 g of active ingredient 70%, and then stirred for 1 hour to produce a drug solution of Comparative Example 1 (only one type of anionic surfactant) Contained).
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Comparative example 2)
A stirrer was placed in a 300 ml polystyrene bottle, and 99.6 g of pure water was charged. While stirring with a magnetic stirrer, 6.8 g of an anionic surfactant sodium dodecyl sulfate (Shinline Rika Co., Ltd. Shinoline (registered trademark) 90TK-T) was added and stirred until completely dissolved.
Subsequently, 22.0 g of the aqueous silica sol prepared in Synthesis Example 3 was added, and subsequently, polyoxyethylene styrenated phenyl ether of HLB = 14.3 (non-ionic surfactant, Neugen (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Neugen (registered 21.4 g of a 70% active ingredient diluted with pure water (trademark EA-157) was added, and stirred for 1 hour to produce a drug solution of Comparative Example 2 (only one type of anionic surfactant). Contained).
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Comparative example 3)
A stirrer was placed in a 300 ml polystyrene bottle, and 128.0 g of pure water was charged. After adding 22.0 g of the aqueous silica sol surface-treated with the silane compound produced in Synthesis Example 4 while stirring with a magnetic stirrer, the solution of Comparative Example 3 was produced by stirring for 1 hour (containing only silane and silica, No surfactant)).
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

(Comparative example 4)
A stirrer was placed in a 300 ml polystyrene bottle, and 121.6 g of pure water was charged. While stirring with a magnetic stirrer, 3.5 g of an anionic surfactant α-olefin sulfonate sodium (Daigen Kogyo Seiyaku Co., Ltd. Neogen (registered trademark) AO-90) was added and stirred until completely dissolved. Subsequently, 3.5 g of an anionic surfactant sodium dodecyl sulfate (Shinolin (registered trademark) 90TK-T, manufactured by Shin Nippon Chemical Co., Ltd.) was added, and the mixture was stirred until completely dissolved. Then, as a nonionic surfactant, HLB = 14.3 polyoxyethylene styrenated phenyl ether (Daigen Kogyo Co., Ltd. Neugen (registered trademark) EA-157) is diluted with pure water and the active ingredient is 70% After charging 21.4 g of the solution, the solution was stirred for 1 hour to produce a chemical solution of Comparative Example 4 (containing only a surfactant, no addition of silica and silane).
After preparing a brine test sample (b) according to the high temperature salt resistance evaluation-2 and holding at 100 ° C. for 60 hours, the sample was taken out and the high temperature salt resistance was evaluated.

Table 1 shows the results of the high temperature salt resistance test of the example, and Table 2 shows the results of the high temperature salt resistance test of the comparative example.
In addition, the kind (code | symbol) of the anionic surfactant in a table | surface and a nonionic surfactant represents the following.
<Anionic surfactant>
AOS: sodium α-olefin sulfonate "Neogen (registered trademark) AO-90", 98.0% active ingredient, Daiichi Kogyo Seiyaku Co., Ltd.
AOS: sodium α-olefin sulfonate “Lipolan® LB-440”, 36.3% of active ingredient, Lion Specialty Chemicals Co., Ltd.
・ SDS: Sodium dodecyl sulfate "Sinoline (registered trademark) 90TK-T", 96.0% of active ingredient, Shin Nippon Chemical Co., Ltd.
<Nonionic surfactant>
-NP-9: polyoxyethylene nonyl phenyl ether "Tergitol (registered trademark) NP-9", active ingredient 100%, Sigma company-EA-017: polyoxyethylene styrenated phenyl ether "Neugen (registered trademark) EA-017 , 100% active ingredient, Daiichi Kogyo Seiyaku Co., Ltd.
EA-127: Polyoxyethylene styrenated phenyl ether "Nuygen (registered trademark) EA-127", 100% active ingredient, Daiichi Kogyo Seiyaku Co., Ltd.
EA-137: polyoxyethylene styrenated phenyl ether "Nuygen (registered trademark) EA-137", active ingredient 100%, Daiichi Kogyo Seiyaku Co., Ltd.
EA-157: polyoxyethylene styrenated phenyl ether "Nuygen (registered trademark) EA-157", active ingredient 100%, Daiichi Kogyo Seiyaku Co., Ltd.
-EA-207D: polyoxyethylene styrenated phenyl ether "Nuygen (registered trademark) EA-207D", 55% of active ingredient, Daiichi Kogyo Seiyaku Co., Ltd.
TDS-90: polyoxyethylene tridecyl ether "Nuygen (registered trademark) TDS-90", 100% active ingredient, Daiichi Kogyo Seiyaku Co., Ltd.

[Crude oil recovery evaluation-1]
Using the crude oil recovery chemical solutions of Example 8, Example 1, Comparative Example 3 and Comparative Example 4 and using a crude oil substitute (n-decane) and a berea sandstone, a crude oil recovery evaluation was performed on the assumption of the underground oil layer.
In addition, the chemical | medical solution for crude oil recovery of Example 8, Example 1 and Comparative Example 3 was adjusted so that it might become 1.0 mass of silica concentration with 3 mass% sodium chloride aqueous solution, and this was made into the sample for crude oil recovery performance evaluation. Moreover, the chemical | medical solution of the comparative example 4 was used as the sample for crude oil collectability evaluation which mixed 100 g of chemical | medical solutions and 200 g of 3 mass% sodium chloride aqueous solution.
As a crude oil substitute, an oil obtained by dyeing n-decane (manufactured by Nacalai Tesque, Inc.) with a red oil-based pigment (manufactured by Inaguma Dye Co., Ltd., oil scarlet) was used.
As a Berea sandstone sample, a sample having a permeability of about 150 mD, a pore volume of about 5 ml, a length of 1.5 inches and a diameter of 1 inch, dried at 60 ° C. for 1 day was used.

The Berea sandstone sample is saturated with salt water by immersing the Berea sandstone sample in 3% by mass sodium chloride aqueous solution in a vacuum vessel and depressurizing the inside of the vessel using a vacuum pump, then the Berea sandstone sample is taken out and weighed The saltwater saturation was determined by the method.
A brine saturated Berea sandstone sample was set in the core holder of a sweeping oil recovery unit SRP-350 (manufactured by Vinci). After raising the temperature of the core holder to 60 ° C, a crude oil substitute (red-colored n-decane) was injected into the berea sandstone sample while side pressure of 2000 psi was applied to the berea sandstone sample using a hydraulic pump, and then the berea sandstone sample was used It removed from the core holder and the amount of oil saturation was calculated | required by the weight method.
After setting the oil-saturated Berea sandstone sample again in the core holder of the sweeping method oil recovery unit SRP-350, brine of 3% by mass sodium chloride aqueous solution was injected into the Berea sandstone sample at a flow rate of 2 ml / min and discharged n From the volume of decane, the rate of recovery of salted water was determined.
Subsequently, the sample for crude oil recovery performance evaluation of the example or the comparative example prepared as described above is pressed into a berea sandstone sample at a flow rate of 2 ml / min, and the oil recovery swept away by chemical solution from the discharged n-decane volume The rate was determined.

[Crude oil recovery evaluation-2]
Crude oil recovery evaluation assuming a seabed oil layer using crude oil substitutes (paraffin oil) and Berea sandstone using the crude oil recovery chemical solutions of Example 13, Example 14, Example 15, Example 16 and Comparative Example 3 Carried out.
In addition, the chemical | medical solution for crude oil recovery of Example 13, Example 14, Example 15, Example 16, and the comparative example 3 is 1.0 mass of silica concentration with the artificial seawater prepared by <high-temperature salt-resistance evaluation -3>. The crude oil was adjusted to be used as a sample for crude oil recovery performance evaluation.
As a crude oil substitute, an oil obtained by staining a crude oil with a paraffin oil ((Showa Shell Petroleum Co., Ltd. Ondina Oil-15) dyed with a red oily pigment (Ashikuma Dyes Inc. oil scarlet) was used.
As a Berea sandstone sample, a Berea sandstone sample dried at 60 ° C. for 1 day and having a permeability of about 150 mD, a pore volume of about 5 ml, a length of 1.5 inches and a diameter of 1 inch was used.

Immerse artificial seawater prepared by <High temperature salt resistance evaluation -3> as salt water in a vacuum vessel as <salt water> and use a vacuum pump to depressurize the vessel to saturate the berea sandstone sample with salt water (artificial seawater) Then, a sample of Berea sandstone was taken out and the saltwater saturation was determined by weight method.
A Berea sandstone sample saturated with salt water (artificial seawater) was set in the core holder of a sweeping oil recovery apparatus SRP-350 (manufactured by Vinci). After raising the temperature of the core holder to 60 ° C, a crude oil substitute (red-colored paraffin oil) is injected into the berea sandstone sample while applying a lateral pressure of 2000 psi to the berea sandstone sample using a hydraulic pump, and then the berea sandstone sample is removed It removed from the core holder and the amount of oil saturation was calculated | required by the weight method.
After re-setting the oil-saturated Berea sandstone sample in the core holder of the sweeping oil recovery unit SRP-350, artificial seawater prepared in <High-temperature salt resistance evaluation-3> is injected into the berea sandstone sample at a flow rate of 2 ml / min. From the volume of paraffin oil discharged, the recovery rate of salted water was determined.
Subsequently, the sample for crude oil recovery performance evaluation of the example or the comparative example prepared as described above is pressed into a berea sandstone sample at a flow rate of 2 ml / min, and the oil recovery rate swept by chemical solution from the volume of the drained paraffin oil I asked for.

Table 3 (Table 3-1, Table 3-2) shows the results of the oil recovery rates of the examples and comparative examples.

<Surface tension evaluation>
The chemical solution for crude oil recovery of the present invention is a chemical solution suitable for surfactant attack in the EOR attack of crude oil recovery. Since the chemical solution for crude oil recovery of the present invention contains a surfactant, the effect of enhanced recovery of crude oil can be expected by reducing the water-oil interfacial tension in the oil layer and improving the replacement efficiency of oil with water.
When the crude oil is to be enhanced and recovered, it is common to dilute the chemical solution and inject it into the underground or submarine oil reservoir. At this time, inexpensive seawater is often used for dilution.
Therefore, the surface tension of each of the high-temperature salt resistance evaluation samples prepared in Example 5, Example 6, Example 7, Example 11, Example 13, and Example 14 was measured as conditions close to actual use situations. .
In addition, as a comparison, Comparative Example 3 prepared with pure water, <high-temperature salt resistance evaluation -3>, artificial seawater, and salt water having a salt concentration of 4% by mass (sodium chloride concentration 3.2% by mass, calcium chloride concentration 0.8% Surface tension was measured.
Table 4 shows the measurement results of surface tension.

As shown in Table 1 (Table 1-1, Table 1-2), the chemical solutions of Examples 1 to 12 and 17 and having a pH of 7 or more and less than 12; Examples 13 to 16; and Example 18 In the chemical solutions of Example 21 having a pH of 2 or more and less than 7, any layer separation or gelation was not observed even after heating for a long time at 100 ° C. in brine. Further, as to the DLS average particle size of the aqueous silica sol (silica particles) in the sample, the ratio of the DLS average particle size after the high temperature salt resistance test to the DLS average particle size of the chemical solution is 1.3 or less. The chemical solutions of Examples 4 to 14 and Examples 16 to 21 all have the above ratio of 1.1 or less, and it is confirmed that the chemical is stable without causing deterioration of the silica sol and is excellent in high-temperature salt resistance. It was done.
In Example 20 and Example 21, the ratio of the DLS average particle diameter after the high temperature salt resistance test to the DLS average particle diameter of the chemical solution is 1.0 in all after 1800 hours (75 days) at 100 ° C. It was confirmed that the chemical was stable and had a high temperature and high salt resistance without deterioration.

On the other hand, as shown in Table 2, the chemical solution of Example 1 using the aqueous silica sol containing no silane compound already had the DLS average particle size at the stage of preparing the high temperature salt resistance evaluation sample before the high temperature salt resistance evaluation test. Became large and aggregated, and a white gel was formed after 7 days at room temperature (normal temperature), resulting in very poor salt resistance.
Also in the chemical solution of Example 2 using an aqueous silica sol in which the mass ratio of the silane compound to the silica in the aqueous silica sol is less than 0.1, white turbidity occurs after <high-temperature salt resistance evaluation-1> and solid-liquid separation occurs immediately. And after 7 days at room temperature (normal temperature), a large amount of white gel was formed, resulting in very poor salt resistance.
Furthermore, the chemical solution of Example 3, which does not contain a nonionic surfactant, is immediately whitened after preparation of the high temperature salt resistance evaluation sample and a white cloudy gel precipitates (DLS average particle diameter: 2768 nm observed), and high temperature salt resistance evaluation is performed. It could not be done, and the result was that the salt resistance was very bad even at room temperature (normal temperature).
Also, the drug solution of Example 4 using a nonionic surfactant having an HLB value of less than 3 separates two layers of water and oil at the preparation stage of the drug solution, because the hydrophobicity of the nonionic surfactant is strong. It did not lead to preparation of a salt tolerance evaluation sample, and high temperature salt tolerance evaluation was not able to be performed.
And, in the chemical solutions of Comparative Examples 1 and 2 in which only one type of anionic surfactant is contained, a white gel is formed after <salt resistance evaluation-1>, and the result is that the high temperature salt resistance is bad. The In the chemical solutions of the above Examples 1 to 21 according to the present invention, it is considered that the packing effect is improved and stabilization is realized by blending two or more kinds of anionic surfactants.

In addition, as shown in Table 3 (Table 3-1, Table 3-2), with regard to the oil recovery rate of the chemical solution (the oil recovery rate of the chemical solution sweeping), Example 8, Example 13, Example 14, Example 15 And the chemical solution of Example 16 obtained high oil recovery with crude oil substitute n-decane and paraffin oil.
On the other hand, the chemical solution of Comparative Example 3 containing only an aqueous silica sol surface-treated with a silane compound (surfactant-free addition) had good high-temperature salt resistance as shown in Table 2; 1, as shown in Table 3-2), the oil recovery rate is relative to any of Example 8 (n-decane) or Example 13, Example 14, Example 15 and Example 16 (paraffin oil) But it was quite low.
Further, the chemical solution of Comparative Example 4 containing only the surfactant without containing the aqueous silica sol had good high-temperature salt resistance as shown in Table 2, but as shown in Table 3 (Table 3-1) [Crude oil The recovered liquid of Evaluation of Recoverability-1] was highly emulsified, and it was difficult to separate oil and water, resulting in that oil recovery could not be substantially performed.
Furthermore, the chemical solution of Example 1 containing an aqueous silica sol which has not been surface-treated with a silane compound causes the pressure of the hydraulic pump to rise immediately after starting chemical solution sweep in the evaluation of [Crude oil recovery evaluation 1]. The drug solution could not be injected. It is considered that this is because the chemical solution is coagulated and clogging occurs in the Berea sandstone.

From the above results, it was confirmed that the chemical solution for crude oil recovery of the present invention is a high-performance chemical solution for crude oil recovery, which is excellent in high-temperature salt resistance and excellent in oil recovery rate.

Further, as shown in Table 4, Examples 5 to 7, Example 11, Example 13 and Example 14 were all pure water, artificial seawater, and 4 mass% salt concentration due to the addition effect of the surfactant. The surface tension was lower than that of the above-mentioned saline solution (sodium chloride concentration: 3.2 mass%, calcium chloride concentration: 0.8 mass%) and the chemical solution of Comparative Example 3. As a result, the water-oil interfacial tension decreases in the oil reservoir, the efficiency of oil substitution by water improves, and the effect of enhanced recovery of crude oil can be expected.

Claims (14)

1. Excellent in high-temperature salt resistance, characterized by containing a silane compound, an aqueous silica sol having an average particle size of 3 to 200 nm, two or more anionic surfactants, and one or more nonionic surfactants. Chemical recovery for crude oil.
2. The high temperature salt resistant crude oil recovery according to claim 1, wherein the aqueous silica sol comprises silica particles in which at least a portion of the silane compound is bonded to the surface of at least a portion of the silica particles in the sol. Chemical solution.
3. Silane coupling agent having at least one organic functional group selected from the group consisting of vinyl group, ether group, epoxy group, epoxy group, styryl group, methacrylic group, acrylic group, amino group and isocyanurate group, alkoxy group, alkoxy group The chemical | medical solution for crude oil recovery excellent in the high-temperature salt tolerance according to claim 1 or 2, which is at least one compound selected from the group consisting of silane, silazane and siloxane.
4. The aqueous silica sol according to any one of claims 1 to 3, wherein the aqueous silica sol is contained in an amount of 0.01% by mass to 30% by mass based on the total mass of the crude oil recovery chemical solution in terms of solid content of silica. A crude oil recovery chemical solution excellent in high-temperature salt resistance according to one aspect.
5. The method according to any one of claims 1 to 4, wherein the silane compound is contained in a ratio such that the ratio of the mass of the silane compound to the mass of the silica solid content of the aqueous silica sol is 0.1 to 10.0. The chemical | medical solution for crude oil recovery excellent in the high temperature salt tolerance as described in any one of-.
6. The said anionic surfactant is a sodium salt or potassium salt of fatty acid, alkyl benzene sulfonate, higher alcohol sulfate, polyoxyethylene alkyl ether sulfate, α-sulfo fatty acid ester, α-olefin sulfonate, monoalkyl phosphorus Selected from the group consisting of acid ester salts and alkane sulfonates,
   The chemical | medical solution for crude oil recovery excellent in the high temperature salt tolerance as described in any one of Claims 1 thru | or 5.
7. The said anionic surfactant is contained by 0.001 mass%-20 mass% on the basis of the total mass of the chemical | medical solution for crude oil collection | recovery, It is described in any one of Claim 1 thru | or 6 A crude oil recovery chemical with excellent high temperature salt resistance.
8. The anionic surfactant is contained at a ratio of 0.4 or more and less than 5.0 as a mass ratio with respect to the silica solid content of the chemical solution for crude oil recovery, and the chemical solution for crude oil recovery is 7 or more and less than 12 The chemical | medical solution for crude oil recovery excellent in high-temperature salt tolerance in any one of the Claims 1 thru | or 7 which have pH of these.
9. The anionic surfactant is contained at a ratio of 0.001 or more and less than 0.4 as a mass ratio with respect to the silica solid content of the chemical solution for crude oil recovery, and the chemical solution for crude oil recovery is 2 or more and less than 7 The chemical | medical solution for crude oil recovery in any one of Claim 1 thru | or 7 which has pH of these.
10. The nonionic surfactant has an HLB value of 3.0 or more and 20.0 or less, and
    It is selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, alkyl glucoside, polyoxyethylene fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester and fatty acid alkanolamide.
    The chemical | medical solution for crude oil recovery excellent in the high temperature salt tolerance as described in any one of Claims 1 thru | or 9.
11. The high temperature salt resistance according to any one of claims 1 to 10, wherein the nonionic surfactant is contained in an amount of 0.001% by mass to 30% by mass based on the total mass of the crude oil recovery chemical solution. Crude oil recovery chemical solution.
12. A method of recovering crude oil from an underground hydrocarbon-containing bed, comprising
    (A) A crude oil recovery chemical solution containing a silane compound, an aqueous silica sol having an average particle diameter of 3 to 200 nm, two or more anionic surfactants, and one or more nonionic surfactants Press-in process,
    (B) recovering crude oil from the production well together with the chemical solution injected into the underground layer;
    Method including.
13. The crude oil recovery chemical solution is adjusted to a pH of 7 or more and less than 12, and the anionic surfactant is a mass ratio of 0.4 or more and less than 5.0 with respect to the silica solid content of the crude oil recovery chemical solution. The method according to claim 12, wherein the method comprises
14. The crude oil recovery chemical solution is adjusted to a pH of 2 or more and less than 7, and the anionic surfactant is a mass ratio of 0.001 or more and less than 0.4 with respect to the silica solid content of the crude oil recovery chemical solution. The method according to claim 12, wherein the method comprises