JPS59184280A - Micelle solution for use in petroleum recovery - Google Patents

Abstract

PURPOSE:To provide the titled soln. which has good resistance to salt and hard water and low interfacial tension and can form a stable emulsion, by incorporating an internal olefin sulfonate and an ethoxylate as surfactants in water. CONSTITUTION:A mixture of a 10-26C internal olefin sulfonate (a) (pref. one having a hydroxyalkane-sulfonate content of at least 40wt% and a disulfonate content of 0.1-15wt%) and a polyethylene alkyl ether of formula I (wherein R<1> is a 10-18C alkyl, alkenyl; m is 3-15) and/or a polyoxyethylene alkylphenyl ether of formula II (wherein R<2> is a 8-15C alkyl; n is 3-15) (b) in a mixing ratio of 19/1-3/7, is used as a surfactant. 4-95wt% water (which may contain oil and an inorg. salt), 1-30wt% said surfactant and 0.1-20wt% surfactant aid are mixed together.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to micellar solutions used in micellar flooding for oil recovery from underground reservoirs, and more particularly to micellar solutions that are capable of forming microemulsions at high salt concentrations;
This invention relates to a micellar solution for oil recovery that can achieve a high oil recovery chamber.

Conventional technology A type of forced oil recovery (E.O.R.) involves creating a transparent microemulsion from water and oil using a surfactant.
There is a micellar attack method in which this microemulsion, called a micellar solution, is injected into an underground reservoir to recover oil.

A lot of research has been done on the process and drugs for micellar attack, for example, US Patent No. 35060
No. 70, No. 3613786, No. 3740343, No. 3983940, No. 3990515, No. 4017405, and No. 4059154.

Among these prior art, petroleum sulfonates, alkylaryl sulfonates, dialkyl sulfosuccinates, alkanesulfonates, polyoxyethylene alkyl ether sulfates, α-olefin sulfonates, and polyoxyethylene alginate are known as surface-lifting activators that can be used in the production of micellar solutions. Various types of surfactants are listed, such as polyether, polyoxyethylene alkylphenyl ether, polyhydric alcohol ester, alkyltrimethylammonium salt, and dialkyldimethylammonium salt.

There are a large number of oil fields currently being extracted, and the properties of underground reservoirs are also rich in diversity. Therefore, the oil fields that are subject to EOR also have various different properties.For example, there are many types of oil reservoir water that exists in underground reservoirs, ranging from those with very little inorganic salts to those with extremely high salt concentrations. The concentration of valent metal ions also varies. Furthermore, the water used in the production of microemulsions is often brine with a relatively high salt concentration. Therefore, the surfactant used in the micelle solution is required to have salt resistance and hard water resistance. In addition, the micellar solution is required to have salt resistance and heat resistance, and the interfacial tensions between water and the microemulsion and between the oil and the microemulsion are both sufficiently low, and are slightly higher than that of the underground oil stored in Fuchu. The viscosity must be easily adjustable (mobility control possible) and the microemulsion must remain stable until an oil bank is formed during sweeping of the oil layer.

Object and Structure of the Invention The object of the present invention is to provide a micellar solution that has good salt resistance and hard water resistance, has a sufficiently low interfacial tension, has good microemulsion stability, and can easily adjust its viscosity.

That is, the present invention provides a micellar solution for use as an injection fluid during forced oil recovery consisting essentially of oil, water which may contain inorganic salts, a surfactant and a surfactant auxiliary, as an essential component of the surfactant. (a) Internal olefin sulfonate having 10 to 26 carbon atoms (hereinafter referred to as IOS); (b) polyoxyethylene alkyl ether (hereinafter referred to as HAE) and polyoxyethylene alkylphenyl ether (hereinafter referred to as APE) at least one ethoxylate selected from the group of (a)/(
b) = 19/1 to 3/7 weight ratio.

Summary of the invention and description of effects The micellar solution of the present invention contains about 2 to about 90% by weight of oil and about 4 to about 4% of water.
The microemulsion is a clear microemulsion containing about 95% by weight, about 1 to about 30% by weight surfactant, and about 0.1 to about 20% by weight surfactant.

The oil used in the present invention can be petroleum, liquefied petroleum gas, crude gasoline (naphtha), kerosene, light oil, heavy oil, etc.; Given the similarities, it is preferred to use recovered petroleum. The proportion of oil in the micelle solution of the present invention is about 2 to about 90% by weight, but since it is economically disadvantageous to use a large amount of oil,
About 3 to about 40% by weight is preferred.

Since the water used in the present invention has good salt resistance and hard water resistance as a surfactant, water or brine having an inorganic salt concentration of 0 to about 10% by weight can be used, and preferably the inorganic salt concentration is about 0.1% by weight.
~8% by weight. Water that can be used in the present invention includes soft water, brine, oil layer water, etc., and for example, rainwater, river water, lake water, groundwater, oil layer water, and seawater can all be used. Examples of alkali metal salts included in brine are NaC
1, KCl, Na2SO4 and K2SO4 are representative.

Further, examples of divalent metal ions are Mg ions and Ca ions, and up to about 4,000 PPM of Mg ions can be tolerated.

In the micelle solution of the present invention, the IOS used as component A of the surfactant has the general formula % (where R and R' are linear or branched saturated carbonized carbon atoms each having 1 or more carbon atoms). hydrogen group, and the sum of the carbon numbers of R and R' is 8 to 24) The essential component is a vinylene type monoolefin having 10 to 26 carbon atoms, preferably 12 to 24 carbon atoms, and optionally about 33 It is produced by sulfonating an internal olefin containing not more than 1/3 of the trisubstituted monoolefin by weight, neutralizing it with an appropriate base, and optionally hydrolyzing it. The IOS thus produced typically contains about 10-60% by weight of alkenyl sulfonates having double bonds and about 90-40% by weight of hydroxyalkanesulfonates, while about 80% or more by weight of monosulfonates. , and up to about 20% by weight of disulfonates. Of course, by selecting the sulfonation conditions and hydrolysis conditions, it is also possible to produce IOS with a different component ratio from the above-mentioned component ratios. Generally, as the number of carbon atoms in the internal olefin increases, the proportion of alkenyl sulfonate tends to increase, and as the molar ratio of the sulfonating agent during sulfonation increases, the proportion of disulfonate tends to increase.

The IOS suitable for the present invention contains about 40% by weight or more of hydroxyalkanesulfonate, preferably about 45-90% by weight.
or more, and about 20% by weight or less of disulfonate,
The content is preferably about 0.1 to 15% by weight or less. When IOS that satisfies these conditions is used, a microemulsion having a sufficiently low interfacial tension can be produced, and as a result, the oil recovery rate is also improved.

The IOS used in the present invention is selected from alkali metal salts, ammonium salts and organic amide salts.

Preferred countercations are Na, K, NH4 and alkanol ammonium. Examples of IOS suitable for the present invention include carbon atoms 12, 13, 14, 15, 16, 18, and 20.
, 22, 24, 12-16, 13-14, 14-16,
Mention may be made of IOSs of 14-18, 15-17, 16-18, 17-20 and 20-24, as well as mixtures thereof.

The ethoxylate used as the B component of the surfactant in the micelle solution of the present invention has the following general formula [I] or [I
I] % formula % (In both formulas, R1 is an alkyl group or alkenyl group having 10 to 18 carbon atoms, R2 is an alkyl group having 6 to 15 carbon atoms, and both R1 and R2 are linear or branched. It may be branched. m and n are average values, m is about 3 to about 10,
n is a number from about 3 to about 15). General formula [I
] Typical specific examples of HAE shown are polyoxyethylene decyl ether (m = 3), polyoxyethylene dodecyl ether (m = 4), polyoxyethylene tetradecyl ether (m = 4), polyoxyethylene Hexadecyl ether (m=8) and polyoxyethylene octadecyl ether (m=6). Also, general formula [
Typical specific examples of APE shown in
=6), polyoxyethylene decyl phenyl ether (
n=7), polyoxyethylene tetodidecyl phenyl ether (n=10), and polyoxyethylene pentadecyl phenyl ether (n=10).

In the present invention, when IOS (A) and ethoxylate (B) are used as surfactants in a weight ratio of A/B = 19/1 to 3/7, the interfacial tension is sufficiently low and the sweeping A microemulsion with good stability against changes in the salt concentration of the oil layer water and mobility controlled can be obtained, and as a result, a high oil recovery rate can be achieved. If the amount of component A is more than this, there is no effect of using component B together, and the mobility of the microemulsion cannot be controlled. On the other hand, if the amount of component A is less than this, a microemulsion with sufficiently low interfacial tension cannot be obtained. The preferred ratio of IOS to ethoxylate is A/
B=9/1 to 4/6.

The micellar solution of the present invention contains about 1 to 30% by weight of a surfactant, but considering the low oil-water interfacial tension and cost, it is preferable that the amount of the surfactant auxiliary is about 3 to about 25% by weight. .

In the micellar solution of the present invention, the surfactant auxiliary is an essential component that works together with the surfactant to form a microemulsion. The surfactant used in the present invention is an alcohol having 4 to 8 carbon atoms, an ethylene glycol monoether of an alcohol having 4 to 8 carbon atoms, and an alcohol having 4 to 8 carbon atoms.
It is an alcohol selected from the group consisting of diethylene glycol monoether of No. 8 alcohol. Specific examples of alcohols suitable for the present invention are butanols, pentanols, hexanols, 2-ethylhexanols, other octanols, butoxyethanol, octoxyethanol and diethylene glycol monobutyl ether.

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 microemulsion stability and ability to reduce oil-water interfacial tension,
Preferably, about 10% by weight is used.

Since the micellar solution of the present invention uses IOS and ethoxylate as surfactants, it can be obtained as microemulsions with various viscosities ranging from low to relatively high viscosity, but it is possible to use a known thickener as an auxiliary. Examples of water-soluble polymers include heteropolysaccharide produced by microorganisms, naphthalene sulfonic acid formalin condensate, polyacrylamide, polyacrylate, hydroxyethyl 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 appropriate amount of micelle solution to be injected at this time is 5 to 25% by volume of the pore chamber of the underground reservoir.

Since the micelle solution of the present invention uses IOS and ethoxylate as surfactants in a specific ratio, it has excellent salt resistance and hard water resistance, and the interfacial tension is sufficiently low, resulting in changes in salt concentration of oil layer water during sweeping. It exhibits the effect of keeping the microemulsion stable.

EXAMPLES 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 component proportions in each sample used in the experiment are weight % unless otherwise indicated.

Example 1 7% of C15-C17 IOS-Na and 7% of the nonionic surfactants listed in Table 1 were used as surfactants, 6% of n-amyl alcohol was used as surfactant auxiliary agent, and A heavy oil (AS) was used as surfactant.
TM, No. 2 oil) 40% and 40% of 2% sodium chloride dissolved in deionized water as brine were weighed into a beaker and stirred at 100 rpm for 30 minutes at 71°C to prepare a microemulsion. The ability of the sample to form a microemulsion was judged from its appearance. If a microemulsion was formed and became uniformly transparent, it was rated "○", and if it was suspended or separated into two phases, it was rated "x".

The interfacial tension was measured using a spinning drop type interfacial tension meter.
The measurement was carried out using an appropriately diluted system at 1°C.

The viscosity was measured at 25°C using a Brookfield viscometer.

The results are shown in Table 1.

Example 2 Mixtures of C15-C17 IOS-Na and polyoxyethylene lauryl ether (m=3 or m=5) in different proportions as surfactants 14% or 12%, n-amyl alcohol 6% or isopropyl alcohol 3% , 40% or 60% of kerosene as oil, and 40% or 55% of 6% sodium chloride dissolved in deionized water as brine were weighed in a beaker and heated at 71°C at 100 rpm3.
A microemulsion was prepared by stirring for 0 minutes. Evaluation of the microemulsion forming ability of the sample and measurement of interfacial tension and viscosity were performed in the same manner as in Example 1. The results obtained are shown in Table 2 together with the proportion of surfactant.

Table 2 shows that mobility control becomes easier when IOS is used in combination with ethoxylate.

Example 3 C15-C17IOS-Na8.3% as surfactant
and polyoxyethylene lauryl ether (m=3)5.
7%, n-amyl alcohol 6% as surfactant aid,
Weigh out 62% of A heavy oil as oil and 40% of an aqueous solution of a predetermined amount of sodium chloride dissolved in deionized water or 40% of an aqueous solution of magnesium chloride or calcium chloride in a sodium chloride aqueous solution as brine, at a temperature of 71°C. A microemulsion was prepared by stirring at 100 rpm for 30 minutes. Evaluation of the microemulsion forming ability of the sample and measurement of interfacial tension were performed in the same manner as in Example 1.

The oil recovery test used a Berea sandstone core 28 cm long and 3.8 cm in diameter with a permeability of 500 mD and a porosity of approximately 20%. The test method was to load a core sufficiently saturated with brine into a core holder, and pressurize A heavy oil at a rate of 6 cc/min until the brine no longer flows out. Subsequently, brine was injected at the same speed and water flooding was performed to recover A heavy oil. Water flooding was continued until the amount of heavy oil A contained in the spilled liquid was below 0.1%.

The micellar attack method was carried out by placing the microemulsion to be press-fitted and the core holder in a constant temperature bath and maintaining the temperature at 71°C.

First, the microemulsion was mixed with 10% pore volume, followed by the polymer solution (Kirintan gum 1000 ppm) with 10% pore volume.
0% pore volume, and finally brine was injected to 100% pore volume to recover heavy oil A.

Note that the press-fitting speed was 2 feet/day. The recovered oil was evaluated by recovering the moisture in the core after the test using an azeotropic method using toluene, determining the core moisture content, and converting it into the amount of oil recovered.

The results obtained are shown in Table 3.

Example 4 C13-C14IOS-NH4,C1 as surfactant
8-C20IOS-K, polyoxyethylene lauryl ether (m = 3) and polyoxyethylene nonylphenyl ether (m = 10), isopropyl alcohol or n-amyl alcohol as a surfactant, kerosene or A heavy oil as oil, and an aqueous solution in which sodium chloride is dissolved in deionized water as a brine, or an aqueous solution in which magnesium chloride or calcium chloride is further dissolved in an aqueous sodium chloride solution to a predetermined divalent metal ion concentration,
Measure the specified amount listed in Table 4 into a beaker, and
A microemulsion was prepared by stirring at 100 rpm for 30 minutes at 1°C.

Evaluation of the microemulsion forming ability of the sample and measurement of interfacial tension and viscosity were performed in the same manner as in Example 1.

The results obtained are shown in Table 4.

Claims (1)

[Claims] 1. In a micellar solution for oil recovery consisting essentially of oil, water that may contain an inorganic salt, a surfactant, and a surfactant, as a surfactant: (a) carbon number; 10 to 26 internal olefin sulfonates, and (b) at least one ethoxylate selected from the group of polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers (a)/(b)
A micellar solution for petroleum recovery characterized by containing the following in a weight ratio of =19/1 to 3/7. 2. Polyoxyethylene alkyl ether has the formula (in the formula,
2. The micelle solution according to claim 1, wherein R is an alkyl group or alkenyl group having 10 to 18 carbon atoms, and 1m is a number of about 3 to about 15 on average. 2. Ethoxy polyoxyethylene alkylphenyl ether represented by the formula (wherein R1 is an alkyl group having 6 to 15 carbon atoms or an alkenyl group, and m is a number from about 3 to about 15 on average) Claim 1 which is a rate
Micellar solution as described in section. 3. Polyoxyethylene alkyl phenyl ether has the formula [II] (wherein, R2 is an alkyl group having 6 to 15 carbon atoms, and n
The micellar solution of claim 1 is an ethoxylate having the average value of from about 3 to about 15.