JPS63264690A - Chemical for crude oil recovery and crude oil recovery method - Google Patents

Abstract

PURPOSE:To provide the title chemical which is useful for recovering a crude oil stably in high recovery rate and simply and which comprises a particular nonionic surfactant and a water-soluble polymer. CONSTITUTION:The title chemical is prepd. by mixing an anionic or nonionic water-soluble polymer (a) having an intrinsic viscosity (1N-NaNO3 aq. soln., 30 deg.C) of 10-25dl/g (e.g., acrylamidesodium acrylate copolymer) with a nonionic surfactant (b) of the formula (wherein R is 5-24C acyl group residue; A is a 2-4C alkylene; m and n are each 0, 1 or more; m+n=1-30) (e.g., coconut oil fatty acid diethanolamide) in a b to a wt. ratio of 1/10-10. Components (a) and (b), premixed or separately, are press-introduced each in a concn. of 0.01-1% into a medium or light-gravity oil reservoir in sandstone having a salt concn. of oil reservoir water of 0.1-10g/dl TDS, a permeability of 10md or more and a temp. of 70 deg.C or less. Thus, crude oil is recovered.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to crude oil recovery agents and crude oil recovery methods.

[Conventional technology]

Conventional crude oil recovery methods include the Micerer polymer flooding method, which involves injecting both Micerer slag (a mixture of petroleum sulfonates, auxiliary agents, brine, water, and oil) and polymer.

[Problem that the invention seeks to solve]

However, this method has the problem that a stable and high recovery rate cannot be obtained because it is sensitive to the effects of salt and polyvalent metal ions in the oil layer water.

[First Means to Solve the Problems] The present inventors have conducted extensive research into a crude oil recovery agent and recovery method that can stably obtain a high crude oil recovery rate and are easy to operate, and have developed the present invention as a result of this research. One piece.

That is, the present invention is based on the general formula (wherein R is an acyl group residue having 5 to 2.1 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and 0m1n is O or 1
or more, m1n = 1 to 30. ) A crude oil recovery agent (first invention) consisting of a nonionic surfactant represented by the formula (1) and a water-soluble polymer, and a nonionic surfactant and a water-soluble polymer represented by the general formula (1) at 0.0
This is a crude oil recovery method (second invention) characterized by injection of 1 to 1%.

General formula (1) (where R is an acyl group residue having 5 to 24 carbon atoms (preferably 9 to 20 carbon atoms) (100-
(except f), and include aliphatic, alicyclic and aromatic hydrocarbon groups.

Examples of aliphatic hydrocarbon groups include saturated or unsaturated hydrocarbon groups, such as alkyl groups having 5 to 24 carbon atoms (pentyl group, 2-ethylhexyl group, octyl group, nonyl group, undecyl group, tridecyl group, Examples include pentadecyl group, hexadecyl group, heptadecyl group, eicosyl group, etc.), alkenyl group (oleyl group, etc.), lyl group, and lylyl group. An example of an alicyclic hydrocarbon group is a cyclohexyl group, and an example of an aromatic hydrocarbon group is an aryl group (phenyl group, naphthyl group, etc.); an aryl substituent;
Arylalkyl group (benzyl group, funinethyl group, etc.)
and aryl alkenyl groups (such as cinnamyl groups)] substituted aryl groups [alkylaryl groups (aryl groups substituted with an alkyl group having 1 to 24 carbon atoms, such as tolyl groups and nonylphenyl groups)], acyl groups The residue may have a substituent (01-1 group, etc.), for example, an OH group-substituted aliphatic hydrocarbon group (OI-I group substituted alkenyl group t Kotoberi silyl group) and an OH group-substituted aromatic hydrocarbon group. (OH group-substituted aryl group, such as salicyloyl group). Preferred R groups include alkyl groups having 9 to 20 carbon atoms, alkenyl groups, and OH group-substituted alkenyl groups. Particularly preferred groups are undecyl groups, They are a heptadecyl group and an oleyl group.

A is an alkylene group having 2 to 4 carbon atoms, an ethylene group,
Examples include propylene and butylene groups. Among A, preferred is an ethylene group.

m + n is 1 to 30, preferably 1 to 10. Specific examples of the compound represented by the general formula (1) include reaction products of fatty acids having usually 6 to 25 carbon atoms and alkanolamines, and alkylenes thereof. Oxide (Ct ~ 4) adduct: Fatty acids include saturated fatty acids (lauric acid, palmitic acid, stearic acid, etc.), unsaturated fatty acids (oleic acid, linoleic acid, lilunic acid, etc.), mixed fatty acids (coconut oil fatty acids, etc.), and hydroxyl fatty acids (lysylsic acid), preferably lauric acid, stearic acid and coconut oil fatty acids; alkanolamines include ethanolamine (mono-, di-), propatoolamine (n-, iso-
) cyclohexylethanolamine, preferably ethanolamine (especially jetanolamine); the molar ratio of acid to amine is from 1:1 to 3, preferably from 1:1 to 2; specific compounds include lauric acid mono- and di-lauric acid; - ethanolamide (1:1 to 2 types); stearic acid mono- and di-ethanolamide (1:1 to 2 types); coconut oil fatty acid mono- and di-ethanolamide (1:1 to 2 types) and their Mixture; coconut oil fatty acid cyclohexylethanolamide (1:3 type), lyrusic acid jetanolamide (1:2 type), lysirucic acid jetanolamide (2 type) and alkylene oxides of the above compounds (C, ~
C,) adducts, etc.

As the water-soluble polymer used in the invention, known anionic and nonionic polymers can be conveniently used. The anionic polymer has the general formula (in the formula, R1 is a methyl group, and Xo is a counter cation) R1 (in the formula, A is NH, O is O, and B is a divalent organic Group, Y
is the countercation. ) R8 (in the formula, % 1111, R4, R, independently represents H or a methyl group).

Monomers that provide the fi4 component represented by general formula (2) include acrylic acid, methacrylic acid [abbreviated as (meth)acrylic acid], and salts thereof (alkali metal salts,
Ammonium salts, lower amine salts, etc.)
Acrylic acid and its salts are preferred.

Monomers that provide the structural unit represented by the general formula (3) include sulfo group-containing (meth)acrylamide, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and p-(meth)acrylamidomethylbenzene. sulfone m,2-t-meth)acrylamide-2-
Phenylethanesulfonic acid, sulfo M-containing (meth)acrylates, such as 2-(meth)acryloyloxy-2,2-dimethylethanesulfonic acid, and salts thereof (alkali metal salts, ammonium salts, lower amine salts, etc.) can give.

Among these, 2-(meth)acrylamido-2-methylpropanesulfonic acid and its salts are preferred.

Examples of the monomer providing the structural unit represented by the general formula (4) include meth(acrylamide) and N,N-dimethyl(meth)acrylamide, but preferably (
meth)acrylamide, particularly preferably acrylamide.

In addition, in the water-soluble polymer according to the present invention, constituent units from other vinyl monomers can be added to the above three units. Examples of other vinyl monomers that can be copolymerized include unsaturated hydrocarbons (such as ethylene, propylene, butylene, isobutylene, and nonene), aromatic hydrocarbons (such as styrene, α-methylstyrene, and vinyltoluene), (
Meth)acrylic acid derivatives, [methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, dodecyl (meth)acrylate, (meth)acrylate
stearyl acrylate, hydroxypropyl (meth)acrylate, triethylene glycol (meth)acrylate), maleic acid derivatives (diethyl maleate, etc.)
, derivatives of vinyl, allyl, and methallyl alcohol (vinyl acetate, vinyl propionate, etc.), vinyl lactam (N-vinylpyrrolidone), N-substituted 1-meth)acrylamide [N-ethyl (meth)acrylamide, N-hexyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-sea n-propyl (meth)acrylamide, N-methytroxyethyl (meth)acrylamide, etc.], (meth)acrylonitrile, (meth)allyl alcohol , vinyl ether (vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, etc.), (meth)allyl ether [
(meth)allyl ethyl ether, poly(oxyethylene-oxypropylene) glycol mono(meth)allyl ether, etc.], mono- and polycarboxylic acids (crotonic acid, vinylbenzoic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, methylenemalonic acid, etc.) and its salts (alkali metal salts, ammonium salts, lower amine salts, etc.), aromatic vinyl sulfonic acid [(meth)allylsulfonic acid, vinylsulfonic acid, styrenesulfonic acid, vinyltoluenesulfone acids, 2-hydroxy-3-(meth)allyloxypropanesulfonic acid, etc.], sulfo group-containing (meth)acrylic acid derivatives [sulfoethyl (meth)acrylic acid, sulfopropyl (meth)acrylic acid, sulfoethyl (meth)acrylamide, Sulfopropyl (meth)acrylamide, 2-hydroxy-3-(meth)acryloyloxypropylsulfonic acid and salts thereof (alkali metal, metal salts, ammonium salts, lower amine salts, etc.)
] etc. These copolymerization amounts are determined by the general formula (2
) to (4), it is usually 50% or less of the total molar release of the vinyl monomers providing the jnE'F-positions.

This invention: Specific water-soluble polymers (polymer consisting of general formulas (2) and (4), general formula (3)
and (4), and general formulas (2), (
Examples include polymers consisting of 3) and (4).

Among these, preferred ones from the viewpoint of crude oil recovery rate are general formulas (2) and (4) and general formulas (2) and (3).
) and (・1) are polymers containing the [j structural unit.

The amount of structural units in a polymer is determined by the general formula (
The unit of 2) is usually 10 to 30 mol%, preferably 13 to 30 mol%.
28 mol%, the degree of general formula (3) is usually 0 to 10%, preferably 2 to 9%, the unit of general formula (4) is usually 60 to 8
9%, preferably 63-85%.

The intrinsic viscosity of the polymer (measured in a 1N NaNOs aqueous solution at 30° C.) is usually from 10 to 25 dl/9, preferably from 15 to 23 di/9. Regarding such polymers, those described in U.S. Pat.

In addition, nonionic polymers such as acrylamide-vinylpyrrolidone polymers and natural polymers such as xanthan gum can also be used.In the present invention, the nonionic surfactant represented by general formula (1) is It can be used in any proportion, but from the viewpoint of crude oil recovery rate, it is generally used in an amount of 4 to 10 times the weight of the water-soluble polymer, preferably in an amount of 5 to 5 times the weight of the water-soluble polymer.
Particularly preferably, the amount is 2 to 2 times the amount. If the amount of the nonionic surfactant is outside the range of 4 to 10 times the amount, the crude oil recovery rate will be low.

The oil layer to which the present invention is applied is not particularly limited, but is generally an oil layer that has been completed by water flooding. As for the reservoir rock quality, sandstone, carbonate, etc. can be used without particular limitation, but sandstone is more preferable from the viewpoint of crude oil recovery rate.The salinity concentration of oil reservoir water is not particularly limited, but is preferably 0.1 to 1 l. O5+/dl!
TDs. There are no particular limitations on the type of oil, permeability of the oil layer, and temperature of the oil layer, but from the viewpoint of crude oil recovery rate, it is preferable that the oil type is a medium-light oil, the permeability is LOMD or higher, and the temperature is 70° C. or lower.

The nonionic surfactant and water-soluble polymer in the present invention are usually injected into the oil layer in the form of an aqueous solution.

At this time, the respective concentrations are not particularly limited, but are generally in the range of 0.001 to 1%.

The water used to prepare the aqueous solution in the present invention is not particularly limited, and any water quality can be used. Tap water, well water, recovered water, etc. can be used, and if necessary, a mixed aqueous solution containing inorganic salts (NaCl, CaCl=, etc.) can be deoxidized by blowing nitrogen gas or natural gas, etc. Alternatively, additives such as hydroquinone, catechol, guanidine sulfate, and thiourea may be added.

In the present invention, known methods can be used to prepare water containing a nonionic surfactant and polymer, inject it into an oil reservoir, and recover crude oil. For example, the order of preparation and injection of an aqueous solution of the same expropriating agent There are no particular limitations on the method, and the surfactant and water-soluble polymer can be mixed in advance or press-injected separately. In this case, both aqueous solutions may be prepared in advance and mixed, or one aqueous solution may be added to and dissolved in the other. Injection into an oil layer can be carried out, for example, in one injection well. Aqueous solution from underground 411
There is a method of injecting oil into a formation, pushing the crude oil out to a production well located one step away, and recovering the crude oil from the production well. Normal crude oil production equipment is used for injection wells and production wells. For press-fitting, equipment normally used for water flooding, such as plunger pumps and diaphragm pumps, can be used. These press-fitting methods are described in Japanese Unexamined Patent Publication No. 55-65696 and U.S. Patent No. 3,039,529. Can also be applied in combination.

〔Example〕

The invention will be further explained below with reference to examples, but the invention is not limited thereto.

Examples 1 to 4, Ratio Examples 1 to 5 The uninvented drug consisted of coconut oil fatty acid jetanolamide (l:1 type) and acrylamide-sodium acrylate copolymer (intrinsic viscosity 20 d//F) use something 1
child.

A cylindrical core made of Berea sandstone with a diameter of 38-1 and a length of 70 mm is set on a core support device so that the fluid passing through it flows in the axial direction, and then the inside of the core is reduced in pressure and N
saturated with brine containing 11% aC, then API gravity 2
Oil with a temperature of 8° and a viscosity of 26 cps (25°C) was injected into the tank until no salt water came out. After that, a solution of the drug of the present invention having the composition shown in Table 1 and a solution of a comparative example were injected into the tank through the IPV. , as shown in Comparative Example 3 as a comparison of the methods. 1111
After 1% of the total weight of sulfonate, n-propyl alcohol, oil, and salt water was injected through IPV,
A polymer aqueous solution (IPV) and salt water (2PV) were press-injected and compared in one example. The results are shown in Table 1 and Figure 1.

Table 1 In addition, in Example 2 and Comparative Example 3, the concentration of salt water was changed as shown in Table 2, and the same procedure was followed, and the results are shown in Table 2.

Table 2 □□□ - A very high recovery rate of 4 was obtained compared to only one comparative example, Xinghui, indicating a strong synergistic effect between the two.

Almost the same recovery rate was obtained as with the My Cellar polymer attack method shown in Comparative Example 3 (Table 1 and 7. ,.

It shows saltiness (Table 2).

〔Effect of the invention〕

The present invention makes it possible to greatly improve the recovery rate of crude oil from oil reservoirs. Moreover, even if the salt concentration in the oil layer changes, or even if divalent metal ions such as calcium salts come out of the oil layer rock, a stable and high recovery rate can be obtained. Furthermore, it can be applied to oil layers with different salinity concentrations and divalent metal ion concentrations, and there is no need to design an engineering composition for each oil field, as in the micellar polymer attack method.

Even when it reaches the practical stage, compared to the polymer attack method, it does not require any new equipment, so it has a very high practical value.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between spill volume (PV) and oil recovery rate (%).

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R is an acyl group residue having 5 to 24 carbon atoms, and A is an alkylene group having 2 to 4 carbon atoms. m and n are integers of 0 or 1 or more, and m+n = 1 to 30.) A crude oil recovery agent characterized by comprising a nonionic surfactant represented by the following formula and a water-soluble polymer. 2. General formula in the oil layer ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R is an acyl group residue with 5 to 24 carbon atoms, and A is an alkylene group with 2 to 4 carbon atoms. , n is an integer of 0 or 1 or more, m + n = 1 to 30.) and a water-soluble polymer are mixed in advance at a concentration of 0.01 to 1%, or A crude oil recovery method characterized by separate injections.