JPS58156694A - Micelle solution for recovery of petroleum - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a micellar solution used in micellar flooding for oil recovery from underground reservoirs, and more particularly, to a micellar solution capable of forming microemulgenes at high salt concentrations;
The present invention also relates to a micelle solution for oil recovery that has a wide compositional range for forming microemulsions, and thus has a high ability to maintain microemulsions even when the composition changes.

(1) Only a portion of the oil contained in underground oil reservoirs can be recovered using primary recovery methods such as bombing, and most of it remains in the underground reservoirs. In order to recover oil that cannot be recovered by this secondary recovery method,
ed Oil Recovery ) (E, 0.R
, ) have been proposed.

B, 0. A method that has been attracting attention in recent years is to create a transparent microemulsion from water and oil such as petroleum or heavy oil, and to inject this microemulsion, also called a micellar solution, into an underground reservoir. There is a micellar attack method to recover oil.

There are many prior arts related to this micellar attack method, such as U.S. Patent Nos. 3,506,070 and 3,613.
No. 786, No. 3740343, No. 3983940
No. 4017405 and No. 4059154.

Among these prior art, surfactants that can be used in the preparation of micellar solutions include petroleum sulfonates, alkyl sulfonates, dialkyl sulfosuccinates, alkanesulfonates, polyoxyethylene alkyl ether sulfates, (2) polyoxy Various anionic, nonionic, and cationic surfactants are listed, such as ethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyhydric alcohol fatty acid ester, alkyltrimethylammonium salt, and dialkyldimethylammonium salt.

The surfactant used in such a micelle solution is required to be inexpensive and easily available since the amount of the micelle solution used is large, but at the same time it must be one that satisfies the above-mentioned required performance. Moreover, the number of oil fields is very large, and therefore the properties of underground reservoirs are diverse, and the available water ranges from soft water containing almost no inorganic salts to large amounts of inorganic salts and polyvalent metal ions. There are a wide variety of brines. Therefore, the surfactant used in the micellar solution must have good heat resistance, salt resistance, and hard water resistance.Currently, petroleum sulfonates are used as surfactants in the micellar method. It is said to be optimal. However, petroleum sulfonates are unsatisfactory in salt resistance, hard water resistance, etc. (3) and have the problem of being applicable only to special oil fields. Therefore, attempts have been made to improve performance by using petroleum sulfonate in combination with other surfactants, but results that satisfy both performance and cost have not been obtained.

The present inventors previously discovered that α- suggested olefin sulfonates. However, when a micelle solution is prepared using α-olefin sulfonate, the composition range in which microemulsion is formed is not wide, so the microemulsion may be destroyed when the micelle solution is injected underground. It has been found that further improvements are required for practical use. Therefore, the present inventors used α-olefin sulfonate, which has excellent salt resistance and hard water resistance, in combination with other surfactants.
As a result of further research aimed at obtaining a micelle solution with a wide composition range in which microemulsins are formed,
The present invention has now been completed (4).

That is, according to the present invention, in a micellar solution used as an injection fluid for forced petroleum recovery consisting essentially of hydrocarbons, water which may contain unruly salts, a surfactant and a surfactant aid, the surfactant The essential component of the agent is (a) α-olefin sulfonate having 10 to 3 carbon atoms (hereinafter referred to as AO5).
(abbreviated as) and (b) dialkyl sulfosuccinate (abbreviated as
(hereinafter abbreviated as 口＾ss) is (a) / (b) −
A micellar solution containing a weight ratio of 8/2 to 3/7 is provided.

Micellar solutions of the present invention suitable for use as injection fluids for forced oil recovery contain from about 4 to about 90 weight percent hydrocarbons, from about 4 to about 92 weight percent water, from 10 to 30(7) carbon atoms, AO8 and D
Surfactant in a weight ratio of 8/2 to 3/7 with ASS from about 3 to
about 30% by weight and about 0.1 to about 20% by weight of surfactant aids
The water that can be used in the micelle solution of the present invention, which is a transparent microemulsion containing
River water, lake water, groundwater, oil layer water, and seawater (5) can all be used freely.

The micellar solution of the present invention has excellent hard water resistance and resistance to alkali metal salts. Therefore, water or brine having an inorganic salt concentration of θ to about 10% by weight can be used to prepare the micellar solutions of the present invention. Preferably, the inorganic salt concentration is about 0.5 to about 8i! [Quantity%. An example of an alkali metal salt contained in water (brine) containing an inorganic salt is N
Representative examples include aC1, KCI, Na25Q4 and 2SO4. For example, seawater has an inorganic salt concentration of about 3.5%, and divalent metal ions are converted to Mg ions, which is about 1,600 PP.
Although M is contained, such a salt concentration is within the preferred range of the present invention.

The AO3 that the micellar solution of the present invention contains as a surfactant component (component a) is suitably one with a carbon number of 10 to 3 degrees, and the nature of the oil field or geological formation, the water (or brine) used, etc.
and surfactant auxiliaries, etc., and may be selected as appropriate.
Preferably AO3 has 12 to 24 carbon atoms, particularly preferably 50% by weight or more of AO8 has 14 to 22 carbon atoms.
The AO3 used in the present invention is an alkali (
6) Remetal salts, ammonium salts and organic amine salts are suitable. Preferred countercations are Na, K+ NH4 & alkanol ammonium. AOS through the present invention
Examples are 1-dodecene sulfonate, 1-tetradecene sulfonate, 1-hexadecene sulfonate, 1-octadecene sulfonate, 1-eicosene sulfonate, 1-tocosene sulfonate, 1-tetracosene sulfonate, carbon number 10 ~14 AOS, carbon number 14 to 16
AO81 AOS with 14 to 18 carbon atoms, 16 to 1 carbon atoms
8 AOS and 20 to 24 carbon atoms. Na
Salt is cheap and easy to obtain.

Other components of the surfactant contained in the micelle solution of the present invention (
DASS, which is component b), is represented by the general formula. R,R
' are each independently an alkyl group having 4 to 12 carbon atoms, and M
is an alkali metal, ammonium or alkanol ammonium.

DASSs suitable for the present invention include dibutylsulfosuccinate, didecylsulfosuccinate, dioccytylsulfosuccinate (including 2-ethylhexyl), and didecylsulfosuccinate. Na salt is preferred because it is easily available.

In the present invention, the area in which microemulsion is formed varies greatly depending on the ratio of AOS and DASS used. When the weight ratio of AOS:DASS is within the range of 8:2 to 3, the area where microemulsion is formed is wide, so when the micelle solution is injected into the underground reservoir, the oil existing underground can be Alternatively, even if the composition changes due to water, the microemulsion can be maintained. Whether the AOS is more or less than this range, the area where microemulsion is formed is narrow, so the practical value is small.
The preferred range of O3/DASS is 7/3 to 4/6.

The micelle solution of the present invention contains about 3 to 30% by weight of a surfactant, but considering the low oil-water interfacial tension and cost, the surfactant content is about 5 to about 25% by weight! Preferably, the amount is %.

(8) Hydrocarbons used as oil phase components of the present invention include petroleum,
Liquefied petroleum gas, crude gasoline (naphtha), kerosene, diesel oil,
Although any oil such as heavy oil can be used, it is preferable to use recovered petroleum because it is cheap, easily available, and has a similar composition to petroleum in underground reservoirs.

The proportion of hydrocarbons in the micellar solution of the present invention is about, to about 90
Since it is economically disadvantageous to use a large amount of hydrocarbons, oil-in-water (0/W) type emulsions are preferred, and therefore the proportion of hydrocarbons is preferably about 5 to about 40% by weight.

In the micellar solution of the present invention, the surfactant is an essential component that cooperates with the surfactant to form a microemulsion.The surfactant used in the present invention has an alcoholic hydroxyl group. a compound, preferably
General formula % formula %) (wherein, n is a number from θ to about 4, R is an alkyl group or alkenyl group having 2 to 8 carbon atoms when n = 0, and n is not O In some cases, it is an alkyl group, alkenyl group, or alkylphenyl group having 6 (9) to 18 carbon atoms, and the aliphatic group may be straight or branched. Specific examples of such alcohols include ethanol, propatools, butanols, pentanols, hexanols, 2-ethylhexanol, other octatools, polyoxyethylene hexyl ether (rt-1), polyoxy Ethylene decyl ether (n=2), polyoxyethylene tridecyl ether (n=4), polyoxyethylene butylphenyl ether (n=2), polyoxyethylene nonylphenyl ether (π=3)1. j (IJ, t-xyethindodecyl phenyl ether (n-4), etc.).

The surfactant used in the present invention is about 0% in the micellar solution.
．． It is used in an amount of 1 to about 20% by weight, but from the viewpoint of the stability of the microemulsion and the ability to lower the oil-water interfacial tension,
About lO! Preferably, 1% by weight is used.

The micellar solution of the present invention uses AO3 as one component (lO) of the surfactant, so it has excellent hard water resistance and salt resistance. Because we were able to widen the compositional range in which microemulsions are formed than in the case of microemulsions, when miser emulsion is injected into underground reservoirs, it is possible to prevent microemulsions from changing in composition over a wide range due to mixing with oil or groundwater. Able to maintain emulsion. This feature of the micellar solution of the present invention is a particularly important advantage in micellar attack, since maintaining the microemulsion in underground reservoirs has a significant impact on oil recovery.

In order to increase the viscosity of the micellar solution of the present invention, known thickeners can be used, such as heteropolysaccharides produced by microorganisms, naphthalene sulfonic acid formalin condensates, polyacrylamides, polyacrylates, hydroxy Examples include water-soluble polymers such as ethyl cellulose and carboxymethyl cellulose.

The micelle solution of the present invention can be easily produced by a known emulsion production method, and the order of addition of each component, stirring and mixing method, temperature, pressure, etc. can be arbitrarily selected.

The method for recovering oil from underground reservoirs using the micellar solution of the present invention is similar to the known micellar attack method, in which the micellar solution is injected from at least one injection well toward an oil-producing well; A seed driving fluid can be introduced to recover the oil. The amount of micelle solution injected at this time is suitably 5 to 15% by volume of the porosity of the underground reservoir.

Next, the present invention will be explained in more detail with reference to examples, but it goes without saying that the present invention is not limited to these examples.The proportions of components in each sample used in the experiment are expressed by weight unless otherwise specified. %.

K1 Takumi 1 7% of AOS sodium salt having 14 to 18 carbon atoms (hereinafter abbreviated as C14 to Cl8AO3-Na) as a surfactant, 7% of an anionic surfactant listed in Table 1, and n-amyl as a surfactant. A sample was prepared by mixing 6% alcohol, 40% A heavy oil (ASTM, No. 2 oil) as a hydrocarbon, and 40% B-line (NaCl concentration 2%),
The formation of a microemulsion was determined by its appearance, and the interfacial tension of the microemulsion was measured.

The results are shown in Table 1 along with the type of anionic surfactant.

The appearance was evaluated as "○" if a microemulsion was formed and became uniformly transparent, and "x" if it was suspended or separated into two phases.

Below is a blank space (13) Example 2 C14~Cl8AO3-Na and bis- as surfactants
Sodium 2-ethylhexylsulfosuccinate (C
8DASS-Na), or petroleum sulfonate sodium salt (TR3-10, manufactured by Liteco, USA), isopropyl alcohol or n-amyl alcohol as a surfactant, heavy oil A and brine (N
aCI concentration 2%) was weighed out and mixed to prepare a sample, the production of microemulzidine was determined by appearance, and the interfacial tension of the microemulzidine produced was measured.

The results are shown in Table 2 together with the blending ratio of each component.

Table 2 shows that when petroleum sulfonate is used, the region where microemulsine is produced is narrow, and when AO8 and DASS are used, the region where microemulsine is produced is wide.

Margin below (15) Example 3 C14C18A OS-Na and C8DASS-Na
Mixtures with different proportions of 14% or 12%, n-amyl alcohol 6% or isopropyl alcohol 3%, A heavy oil 40% or kerosene 30% and prine (NaC 12%)
Samples were prepared by mixing 40% or 55%, and the formation of a microemulsion was determined by appearance, and the interfacial tension of the formed microemulsion was measured.

The results are shown in Table 3 along with the proportion of surfactant.

Margin below (17) Example 4 Microemulsions were prepared using various combinations of AO3 and DASS as surfactants, and the formation of microemulsions was determined by appearance and interfacial tension was measured.

The results are shown in Table 4 along with the composition.

Margin below (19) 573-

Claims (1)

[Scope of Claims] 1. In a micelle solution for petroleum recovery consisting essentially of a hydrocarbon, water which may contain an inorganic salt, a surfactant, and a surfactant auxiliary, as a surfactant (a) carbon number; 10-3
0 α-olefin sulfonate and (b) dialkyl sulfosuccinate, (a)/
<b) - A micelle solution for oil recovery characterized by containing in a weight ratio of 8/2 to 3/70.