NO860166L - ETERAMINE OXIDES, THE PROCEDURE FOR THEIR PREPARATION AND THEIR USE AS TENSIDES FOR THE TERTIARY OIL EXTRACTION. - Google Patents

Description

When extracting oil from underground formations, it usually only succeeds in conveying 20-30% of the oil originally present by means of the primary extraction process. In this way, the oil comes to the surface of the earth with the help of natural formation pressure. During secondary extraction, water is forced into the geological formation and the oil is transported through several production wells. This water flooding as a secondary precaution is relatively cheap and is therefore often used, however, in many cases it only leads to a slight further erosion of the formations.

After completion of the secondary crude oil transport precautions, it is not possible to achieve further economical crude oil extraction by supplying mechanical energy alone. In the heterogeneous pore space, the lower viscous water passes the higher viscous oil, so that only water and not oil is conveyed. Has the degree of watering at approx. 98% exceeded the profitability limit, then only methods of tertiary petroleum extraction come into question. This is understood as methods where either the viscosity of the oil is lowered and/or the interfacial tension between water and oil is lowered.

Most methods can be classified as thermal oil extraction methods, solution or mixture flotation, surfactant or polymer flotation or as a combination of several of the methods mentioned.

The surfactant swimming process depends on a strong lowering of the interfacial tension between oil and swimming water. According to surfactant concentrations, surfactant swimming (Low tension flooding), micellar swimming and emulsion swimming are separated.

In the monograph by D.O. Shah and R.S. Schechter: "Improved Oil Recovery by Surfactant and Polymerflooding", Academic Press Inc., as well as numerous patent documents list a majority of surfactants that can be used in the surfactant flooding process. As surfactants, sulfonates are mentioned above all, e.g. synthetic and natural petrol sulphonates, alkyl sulphonates, e.g. ^ 2_ 3~(~' 20 sec"alkanesulfonate-Na MG 328/350, α-olefinsulfonate-Na, alkylarylsulfonates e.g. dodecylbenzenesulfonate-Na, alkyltoluenesulfonates or alkylxylenesulfonates.

However, these sulphonates only have a very low tolerance limit for the salt content of the formation water. Thus, e.g. the petrol sulphonate is only soluble in water with a salt content of 1.5% NaCl. Above all, the sulphonates are also very sensitive to the alkaline earths contained in the formation water. At higher salt concentrations, when these surfactants are used, precipitation products form which can lead to clogging of the porous space of the formation.

In the patent documents DE 3025 383 and DE 3014 510, the use of amine oxides, e.g. alkyl dimethyl amine oxide or naphthyl phenol amide propylene dimethyl amine oxide. These compounds are distinguished by their compatibility with high-salt water, but the oil-mobilizing effect is not sufficient.

Surprisingly, it was found that alkyl and alkyl aryl ether amine oxides are superior to the above mentioned compounds when used as surfactants for petroleum transport.

The subject matter of the invention is alkyl and alkylaryl alkoxy amine oxides with the formula:

where R means C 8 -C 4 -alkyl, C 8 -C 4 -alkenyl or C 4 - C 4 -alkylaryl, R 4 and R - are the same or different and means C 1 -C 4 -alkyl, x means a number from 2 to 12 and R^ means a group of formula -C2H4~ and/or -C^Hg-,

As R., ethylene is preferred. As alkylaryl groups, alkyl-phenyl groups are preferred, for example octylphenyl, dinonylphenyl, dodecylphenyl or tributylphenyl. As alkyl residues, it is advantageous to have C8-1"18' which can be derived from natural or synthetic alcohols as well (sec. alcohols, oxalcohols). The term alkylaryl includes mono-, di- and trialkyl groups, as each alkyl group can have 4- 18, preferably 4-9 C atoms.

For the production of the amine oxides according to the invention,

the corresponding oxethylated alcohols resp. phenols of the general formula

in which R, R^ and x have the above meaning, halogenated "end-placed, e.g. with thionyl chloride, or PBr^ or sulfated, e.g. with SO^ or Cl-SO^H. These intermediates are then reacted in autoclave under pressure at temperatures of approximately 120-200° C, preferably at 170° C with a dialkyl amine of the formula HNR^R 2. The etheramines thus formed are then oxidized with a suitable oxidizing agent, for example with hydrogen peroxide at temperatures of approximately 65 -80°C to the amine oxides according to the invention.

i The etheramine oxides with the aforementioned formula are surfactants, which are distinguished by their resistance to Ca ions in a wide temperature range. They are particularly suitable for tertiary crude oil transport, for probe stimulation and Frac treatment of crude oil formations. The application of the fdor compound

in accordance with the invention reduces the pressing-in pressure (injection pressure) of the flotation medium and increases the oil yield in these methods. In all cases, the surfactant is added to the bathing water usually in amounts of 0.01-10%, preferably 0.05-3%.

The etheramine oxides can also be used in combination with anionic surfactants, such as e.g. alkanesulfonates, α-olefinsulfonates, petrolsulfonates, alkylarylsulfonates, alkylsylenesulfonates and other, non-ionic surfactants, such as alkyl-resp. alkylphenol polyglycol ethers. Mixtures of the amine oxides according to the invention and the alkanesulfonates in mixing ratios from 1:1 to 1:4 are therefore of particular interest. Additional additives include alcohols and glycol ethers. The viscosity of the make-up water can also be increased by polymers, such as hydroxyethyl cellulose, polyacrylamines, copolymers based on acrylamide or polysaccharides.

Example_l

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a) 464 g (0.82 mol) lauryldioxyethyl sulfate-Na (68%), 139.4 g (1.24 mol) dimethylamine solution (40%), 40 g

(1.0 mol) NaOH is heated with stirring together with 700 ml of distilled water for 10 hours at 175°C in an autoclave. After distilling off residual water and excess dimethylamine from the organic phase, . man 245 g (252 g theoretical) of the tertiary amine (total base N: 4.2% / tert. N: 4.2%).

b) 100 g (0.31 mol) of the amine is emulsified in 210 ml of water and heated to 70°C. Without additional heating

37.1 g (0.33 mol) f^C^(30%) are added drop by drop and then stirred for 4 hours at 70°C. Thereby, lauryl di-oxetyldimethylamine oxide is produced in approximately quantitative yield.

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E£§5}§£iiiiD9_§Y_t£i^utYlf §D2i2?Sta2lS§§tYl^im§tylaminoxYd_ Corresponding to the procedure mentioned in example 1, tributylphenyloctaoxyethyl sulfate is reacted with dimethylamine to the amine (tert. N: 1.8% / total base N: 1.8%) and oxidized with ^ 2°2 amine°oxyd.

Example_3

?£§ros ti Iling _av_kokosalky^]oen^ Analogous to the procedure indicated in example 1, cocoalkylpentaoxyethyl chloride is reacted with dimethylamine to tertiary amine (tert. N: 2.6% / total base N: 2.6%) and with-i-H^O ^ tdl dimethylamine oxide.

To determine the effect of the compound according to the invention, the micro-capillary deoiling method described in US patent 4,008,165 is used, determination of the interfacial tension according to the Spinning-drop-Tensiometer method and the phase relationship according to Winsor.

In the case of microcapillary deoiling, glass microcapillaries from the company Drummond Scientific Co.., USA, which have a length of 30 mm and a diameter of 0.45 mm at a volume of 5 ul, are used as a model for the pore space of the formation. The microcapillaries are melted at one end, evacuated in a desiccator and filled with crude oil. The capillaries are introduced vertically into surfactant solutions (reagent tubes), which are tempered in a water bath with the opening upwards vertically and the displacement of the oil is recorded visually as a function of time.

The experiments are repeated 10 times, and the mean value is taken.

in

With the help of the following evaluation form, the effect of the surfactant can be determined depending on its concentration, salt concentration, pH value, temperature and oil composition.

IN

Value

9 empty (30 mm) after.10 minutes

8 empty after 1 hour

7■ empty after 3 hours

6 empty after 20 hours

5 16-25 mm emptying after. 20 hours

4 9-15 mm emptying after 20 hours

3 4-8 mm emptying after 20 hours

2 1-3 mm emptying after 20 hours

1 track emptying after 20 hours

0 unchanged after 2 0 hours

This method offers the advantage that at the small diameter

of the microcapillaries, viscosity and density of the oil do not have a major impact on the deoiling effect and it is possible to work with formation oil and formation water.

According to Taber J. Petr. Technology 3 (1969), pp. 3-12, surfactants are suitable for tertiary petroleum extraction only when the interfacial tension at the oil/saltwater phase boundary is lowered to

-2 -1

values less than 10 mNm. For this determination of the interfacial tension at the oil/water phase boundary, the Spinning-drop-Inter-facial-Tensiometer developed by Wade and Burkowsky is used. (M. Burkowsky and C. Marx: Uber den Mechanismus des Tensidflutens i hochsalinaren Systemen, Erdol-Erdgas-Zeitschrift 95 (1979), pp. 17-25.

The method is based on the fact that an oil drop brought into a capillary rotating around the horizontal axis, which contains a liquid (salt water and surfactant) with a high density, is deformed. The drop is stretched until it reaches an equilibrium between deforming forces and interfacial tension.

The interfacial tension is calculated according to Vonnegu (B. Vonnegut, Rev, Sei. Instruments 13 (1942), pp. 6-9) and Princen (H. M. Princen, J.Y.Z. ZIA and S.G. Mason, J. Coll. Int. Sei 23 (1967) 99 -107).

From the measured oil droplet diameter R, the rotation speed W and the density difference Ad according to the following formula:

The values measured with these methods are listed in the following tables. In all cases, 1% aqueous solutions of the surfactants were respectively used. According to the state of the art, coconut dimethylamine oxide was used as a comparison product.

According to the current state of elucidation of the mechanism of de-oiling during surfactant flotation, the formation of a 3rd phase (middle phase) of a microemulsion is the prerequisite for an optimal surfactant flotation result.

/Rieckmann, M. Tertiare Erdolgewinning, Erdol und Kohle-Erdgas-petrochemie 36 (1983) 281-282) Healy, R.N. and

Reed, R.L. Soc. Petr. Meadow. J. 10 (1979) 492-501), Obah,

B. and Neumann, H,J. uber die Bildung von Mikroemulsion Tenside Detergents 20 (1983) 145-151/

This sought-after third phase occurs in the system, when the interfacial tension at the oil/saltwater phase boundary is greatly lowered.

When determining the middle phase, 5 ml of surfactant solution (with salt water) and 5 ml of oil are placed in a test tube, the test tube is fused together, shaken vigorously and stored in a drying cabinet at a constant selected temperature.

After an hour's storage time, shake vigorously again and the test tubes are then stored without further thorough mixing. After a storage time of 1 day and 7 days, the formation of a middle phase is confirmed.

The experimental results (Tables I - XI) show that the ether amine oxides and their mixtures with sec-alkanesulfonates (C,-.-C,0, MG 328)

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at different salt contents (50-200 g/l), temperatures (20-80°C) and also at high contents of Ca ions, the already known alkyldimethylamine oxides are superior as surfactants for tertiary petroleum extraction.

Claims (4)

1. Etheramine oxides with formula where R means C 8 -C 4 -alkyl, C 8 -C 4 -alkenyl or C 4 -C 18 ~ alkylaryl, R 1 and R 2 are the same or different and mean C 1 -C 4 -alkyl, x means a number from 2-12, and R^ means a group of the formulas -C2 H4 - and/or -C^ Hg-. 2. Process for the production of ether amine oxides according to claim 1, characterized in that a compound of formula is oxidized, where R^ -R^ has the above meaning.. 3. Use of the compounds according to claim 1 as an aid in crude oil transport. 4. Use of the compounds according to claim 3 together with alkanesulfonates, α-olefinsulfonates, dodecylbenzenesulfonates, petrolsulfonates, alkyl or alkylphenyl polyglycol ethers, alkylarylsulfonates or alkyltoluenesulfonates.