DD207726A5 - PROCESS FOR PREPARING A WATER-SOLUBLE COPOLYMERISATE - Google Patents

Abstract

The invention relates to a method for producing a water-soluble copolymer which is added during the stimulation of natural gas and oil drilled holes by means of pressure control with a sulfuric solution to the acids used as friction inhibitors. THE INVENTION COPOLYMERISATE INCLUDES AT LEAST 5% BY WEIGHT OF UNITS WHICH HAVE A FORMYLAMINOGRUPPE OF FORMULA A), WHICH IS HIGH 1 HYDROGEN, METHYL OR HYDROXYLMETHYL, AND AT LEAST 10% BY WEIGHT OF UNITS WHICH ARE AN AMINOCARBONYL GROUP OF THE FORMULA B). THE COPOLYMERISATE IS SITUATED IN A STATIC DISTRIBUTION OF 5 TO 50% BY WEIGHT OF UNITS OF FORMULA I, 10 TO 95% BY WEIGHT OF UNITS OF FORMULA II AND 0 TO 85% BY WEIGHT OF UNITS OF FORMULA III TOGETHER. R HIGH 1 = HYDROGEN, METHYL OR HYDROXYMETHYL; R HIGH 2 = HYDROGEN OR METHYL; X = CYAN, CARBOXYL U.A. FORMULAS A), B), I, II, AND III. DD # AP

Description

Copolymer .... ______ '·>' '

Field of application of the invention

The invention relates to a process for the preparation of a water-soluble copolymer, which is added in the stimulation of natural gas and oil wells by acidification with an acid solution and the acids used as a friction reducer. " ~ '\

Characteristic of the known technical solutions

A well-known stimulation technique for oil and gas wells used for the purpose of increasing the production rate and the overall yield from subterranean carbonate formations is so-called pressurized acidification. Carbonate formations in this sense are, for example, dolomite, limestone or other storage rocks containing calcareous material The pressurized acidification is generally carried out in such a way that an aqueous acid, which may optionally also contain so-called proppants, is pumped into the bore to be stimulated, under a pressure which exceeds the formation pressure. new cracks and channels, so-called fractures, are broken up into the formation. In the pressurized acid technique, the pressed-in acid additionally etches the surfaces of the rock formations and, if the acid additionally contains a proppant, this proppant becomes open fractures hineint Both the irregular etching of the heterogeneous fracture surface and the deposition of the support material cause fractures to

62 111/11

load can not close completely anymore. In any case, creates a better-permeable channel, which makes it the. Petroleum or natural gas allows to flow to the production well after pressure relief.

In the case of the acidification process, it is necessary to pump the acid, the so-called fluid, into the well at high speed in order to be able to build up the required explosive pressure for the rock. It turns out that a considerable proportion of the injection pressure is lost by frictional forces which occur between the fluid flowing in turbulent flow and the conduit walls. Since this pressure loss, the so-called friction pressure, increases with the rate of injection, an increasingly lower pressure component than the treatment pressure is transferred hydraulically to the formation as the injection rate increases. By adding low concentrations of polymers to the treatment fluid, the flow of the pumped fluid is now laminarized, so that even at high injection rates, the friction pressure is significantly reduced and thus a much larger proportion of the head pressure is transferred to the storage rock. -

Common friction reducers that are used in the implementation of pressure acidification are polysaccharides, such as. As hydroxyethylcellulose, xanthan gum (metabolite of Zanthomonas campestris) hydroxypropylated guar gum (from the seeds of Cyanaposis tetragonolibus) or synthetic polymers based on polyacrylamide.

When .. Use of polysaccharides as friction reducers resulting problems that these compounds are not very stable in highly concentrated acids, usually

62 111/11

/. ft Q .Rn 1 -3-

Polysaccharides are hydrolyzed or degraded in strong acids, whereby the friction-reducing effect is lost. The use of synthetic polyacrylamides as friction reducers has disadvantages: '

In the presence of strong acids, polyacrylamides are rapidly hydrolyzed to insoluble degradation products. These precipitate out of the treatment fluids and can lead to blockage of the fraction, to a hindrance of the oil or gas flow and thus to severe damage to the deposit.

Object of the invention .

The object of the invention is to provide novel friction reducers which are acid stable and do not provide insoluble degradation products, thus allowing an increase in the flow rate. ,

Explanation of the essence of the invention; '-

The invention has for its object to find new compounds with the desired properties, which are suitable as a friction reducer in intended for the pressure acidification acids.

According to the invention, a copolymer is provided which, in statistical distribution in its macromolecule

 .. · '. /

containing at least 5 wt .-% of units which have a formylamino group (A) and at least 10 wt .-% of Ein¬ units, which contain an Aminocarboay! group (B).

0 ..0. , ,

H .,

62 111/11

ti

The copolymer of the invention can be used as an improved friction reducer for the pressure acidification of subterranean, calcareous formations. The polymer according to the invention is acid-soluble, and its degradation products are both acid-soluble and stable.

Preferably, the new copolymers according to the invention are composed of 5 to 50% by weight of units of the formula I ^; , ·.

-CH ₀ -CH- <- t

HC R ¹

10 to 95 wt .-% of units of the formula II

₀ -CH-

² ''. - (H)

CO-IIH ₂ 'and 0 to 85 wt .-% of units of the formula III

R ²

t .-.

-CH ² -C- ""... CIII).

wherein R is hydrogen, methyl and or hydrosymethyl and

ρ R is hydrogen or methyl and Σ is cyano, carboxyl, or its alkali or ammonium salts, alkoxycarbonyl having 1 to 6, preferably 1 to 3 carbon atoms, hydroxyalkoxy "'carbonyl having 1 to 3 carbon atoms; U-MethyIölamidocarbonyl

62 111/11

248 960 1 \ -5-

of the formula HOCHgHH-CO-, whose methylol group may also be etherified with alkanols having 1 to 4 carbon atoms; Alkanoylamino having 1 to 4 carbon atoms which may optionally be substituted by methylol or alkyl having 1 to 4 carbon atoms! Pyrrolidonyl (1); phenyl; pyridinium; the sulfonic acid group; Sulfoalkylamidocarbonyl of 1 to 4 carbon atoms; the phosphonic acid group, wherein sulfonic acid and phosphonic acid groups may also be present as alkali metal or ammonium salts ; a remainder of the Pormel IV

· '. o; . ''. ·· ·

It

-COOCH ₀ CH ₀ ^ OPR ³ . (IY),

wherein R ^ and R are the same or different and are alkyl

with 1 to 4, preferably 1 or 2, carbon atoms, a residue of Pormei V.

R \

wherein R and R have the meanings given above and ρ is a number of. 1. to 4 stands; or a remainder of the Pormel

COHH-C Hp -H ^ ^; (VI)

wherein R and R are the same or different and are alkyl, having 1 to 4, preferably ί or 2, carbon atoms

⁺ . 62 111/11

248 9 60 V.- ⁶ -. ^: ...

and ρ is a number from Ϊ to 4; and the formulas Y and YI corresponding, for example, by dimethyl sulfate or methyl chloride quaternized groups means.

The. Inventive copolymers are random, i. that is, the distribution of units I to III in the macromolecule is statistical.

Of course, the novel copolymers can contain several different units of the formulas I and III, for. B. different units of the formula III, which differ from each other by different meaning of the radicals X or R. As a rule, in a single macromolecule X no more than 3, preferably no more than two, have different meanings. Copolymers of this type are prepared by adding several different comonomers, usually not more than three, preferably not more than two, characterized by different meanings of the radical

2 '

X and / or R differ from each other, used in the copolymerization. As a rule, the copolymers of this invention have K values (see Fikentscher, "Cellulose Chemistry" Bd 13 , page 58 (1932) between 25 and 250, which corresponds to molecular weights between 20,000 and 15 × 10. Preferred as friction reducers are copolymers according to the invention that have K values between 50 and 200, corresponding to molecular weights between 100,000 and 4 χ 10.

Preferred copolymers of the invention consist of 5

to 30% by weight of units of the formula I, 50 to 80% by weight

of units of formula II and 1 to 60 wt .-% of units of formula III.

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248 9 60 I - ⁷ -

In addition, preference is given to those copolymers in which R is hydrogen or methyl, or those in which X is carboxyl, the sulphonic acid group, 3-sulpho-2-methylpropyl- (2)

amidocarbonyl of the formula

CH,. , '.

1 J '..,'

CH ₃ *. , ·

Alkanoylamino having 1 to 4 carbon atoms, which may optionally be U-substituted with methylol or alkyl having 1 to 4 carbon atoms, pyrrolidonyl-d) or a radical .der formulas given above and defined. Y or 71, wherein each acid group may also be present as an "E" atrium potassium or ammonium salt.

Particularly preferred for use as a friction reducer in the stimulation of natural gas or oil wells are such copolymers of the invention, in which the units of formula I by concomitant use of Ii-7inylformamide and the units of formula III by the concomitant use of ST-vinyl-N-methyl acetamide, ÜT-Yinylpyrrodilon or 2-acrylamido-2-> methyl-propane-sulfonic acid or mixtures thereof were introduced in the copolymerization. . ' '

The copolymers of the invention are readily soluble in water or aqueous acids and therefore can be handled easily. When used in pressure-acidification processes, the polymers can be added to the acid in the form of aqueous 0.5 to 6% strength by weight solutions (polymer solutions having a concentration of more than 6% by weight are too viscous and therefore difficult to handle), in the form of hydrocarbon

62 111/11

24 8 9 6 0 1 - ⁸ -

Dispersions containing emulsifiers and 20 to 50 wt .-% of the polymer, or in the form of Ql-in-water or water-in-oil emulsions containing emulsifiers and 20 to 50 wt .-% of the polymer · Preference the copolymers according to the invention in the form of a water-in-oil emulsion having the highest possible polymer content, usually 20 to 75 wt .-%, used. Oils, which are suitable for the preparation of these water-in-oil emulsions are, for example, branched or unbranched paraffinic hydrocarbon-material fractions having a boiling range of 150 to 250 ⁰ C, depending on the monomer Zusammensetzung'und the resulting properties act copolymers of the invention in concentrations of 0.06 to 0.12 wt .-%, at temperatures of normal tree temperature up to temperatures above 80 ⁰ C as a highly effective friction modifiers, wobei.die duration of action for a long time, for example more than 10 days stops, Even upon the occurrence of hydrolytic degradation of side chains of the copolymers, the degradation products remain acid-soluble and do not precipitate out of the solution. Preferably, the copolymers according to the invention are combined with acids which are liquid under hormonal conditions and in particular with inorganic or strong lower organic acids. Examples of acids which can be used together with the copolymer according to the invention are. Hydrofluoric acid, hydrochloric acid, formic acid ,,, acetic acid, monochloroacetic acid, di chloroacetic acid or trichloroacetic acid. The most common is the use of hydrochloric acid used in concentrations of 3 to 28% by weight, depending on the conditions required for handling and the properties of the deposit.

The copolymers according to the invention are prepared by copolymerization of from 5 to 50% by weight of a given

2489 60 1 _ - ₉ . ^{62111 /} "

if N-substituted vinyl ammonds of the formula Ia

R ¹ "'''' CH ₉ = CH-UC 1 '(Ia),

10 to 95% by weight of acrylamide and 0 to 23% by weight of an ethylenically unsaturated monomer of the formula IIIa. - _s

'R ² ' -. ''.-

t -.

CH ₂ = CX. (IIIa)

12

where R., R and Σ.the. have the meanings given above;

Preferably 5 wt .-% bis 30 of vinylformamide of the formula (Ia), comprising 50 to SO -.% Of acrylamide and 1 to 60 wt .-% copolymerized of the monomer of formula IIIa. A particularly preferred composition is -10 to 20 wt .-% N-vinylformamide, ^'V 50 to 70 parts by yä acrylamide and 10 to 40 wt -.% Of a monomer of formula IIIa. ,

If copolymers are to be prepared which are several different

2 '

Have radicals Σ and / or R in the component-III, so are used for the copolymerization several different, usually 3, or preferably 2, different comonomers of the formula IHa. _: ,

The copolymerization can be carried out by all known polymerization processes, in the range of pH 4 to 12, preferably 6 to 9).

To adjust the pH, alkaline salts of alkali metals, eg. B. Alkalicarbo-

0 62 111/11

  1 - ίο -

      «.

nate, alkali hydrogen carbonates, alkali metal borates, di- or tri-alkali metal phosphates, alkali metal hydroxides, ammonia or organic

Amines of the formula NRA used, wherein R 'is hydrogen, alkyl having 1 to 4 carbon atoms or hydroxyethyl and wherein

7 at least one of the radicals R is different from hydrogen.

Preferred bases for adjusting the pH are the abovementioned alkali compounds, in particular sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ¹ potassium carbonate and potassium bicarbonate, and sodium or potassium borates. Another preferred base is NEW.

The polymerization reaction can be initiated by high-energy electromagnetic or corpuscular radiation or by substances that form radicals. Accordingly, suitable as polymerization initiators are organic per compounds, such as. B. benzoyl peroxide ,. Alky! Hydroperoxide, such as. B .. Butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, diacyl peroxides, such as 2. B. di-, tert-butyl peroxide or inorganic per-compounds, such as. B, potassium or ammonium persulfate and hydrogen peroxide, further azo compounds, such as. Azo-bis-isobutyronitrile, 2,2'-azo-bis (2- a- midinopropane) hydrochloride or azo-bis-isobutyramide. It is advantageous to use the organic or inorganic per compounds in combination with reducing substances. Examples of suitable reducing substances are sodium pyrosulfite, sodium hydrogensulfite or condensation products of. Formaldehyde with sulfoxylates. The polymerization can be carried out particularly advantageously with the use of Mannich adducts of sulfinic acids, aldehydes and amino compounds, as described, for example, in German Patent 1,301,516.

62 111/11.

2E8950 I - "-

It is also known to add to the polymerization batches small amounts of so-called moderators, which harmonize the course of the reaction by flattening the reaction rate-time diagram. They lead to an improvement in the reproducibility of the reaction and thus make it possible to produce uniform products with extremely low quality deviations. Examples of suitable moderators of this type are Hitrilo-tris-propionylamide or hydrohalides of monoalkylamines, dialkylamines or trialkylamines, such as. B. dibutylamine hydrochloride. Also in the preparation of the copolymers according to the invention such moderators can be used with advantage.

Furthermore, so-called regulators can be added to the polymerization batches; these are those compounds which influence the molecular weight of the polymers produced. Useful known regulators are z. As alcohols, such as methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, and amyl alcohols, alkyl mercaptans, such as. B .... 'Dodecalmercaptan and tert-dodecalmercaptan, isooctylthioglycolate and some halogen compounds, such . B, carbon tetrachloride, chloroform and methylene chloride.

The polymerization is usually carried out in a protective gas atmosphere, preferably under nitrogen.

, The reaction may be in solution, in emulsion or under the loading. conditions of precipitation polymerization at temperatures of from '20 to 120 · ⁰ C, preferably from 40 to 100 ⁰ C, are carried out. When water is used as a solvent for the polymerization reaction, it proceeds in solution, and an aqueous viscous solution of the copolymer is obtained. ":

62 111/11

2489 6 0, 1-12-

The reaction product can be isolated either by distilling off the water from the solution or by. Mixing the aqueous solution with organic solvents which are completely miscible with water, but in which the copolymer is insoluble. Upon addition of such organic solvents to the aqueous polymer solution, the resulting polymer or copolymer precipitates and can be separated from the liquid phase, e.g. B. by filtration, are separated. Preferably, however, the resulting aqueous solution of the polymer or "copolymer is used directly for the further use, if appropriate after adjustment to a certain desired concentration. '

When the copolymerization is carried out in an organic solvent such as, for example, in a lower alkanol, e.g. B. in tert-butanol, is carried out, it proceeds under the conditions of the precipitation polymerization. In this case, the resulting polymer or copolymer precipitates in the course of the reaction in solid form and can leipht in a conventional manner, such as. by suction and subsequent drying. Of course, it is also possible * and in some cases preferred to distill the solvent out of the reaction mixture.

Monomers which introduce into the copolymers units of formula I are U-Vinalformamid., N-vinyl-U-methylformamide and! I-Vinj ^ l-N-hydrozymetiiylformamid, the first two are preferred. The concomitant use of acrylamide in the copolymerization units of the formula II are introduced into the copolymer. Units of the formula III. are introduced into the copolymer of the invention by the concomitant use of one or more, preferably 2 mono-. mers of the formula

9 60 111/11

-'Λ3 -

CH ₂ - C

i-

 j ''

wherein R and X have the following meanings:

2 j - ^H -CH ₃ -H ! -oh3 ι -H I-H '. X I. '-CK COOH ^ ' M-COOH ^ ¹ ^ L 3H _3- M-CHO I - · -

-CH

-H

! CH. f -H

CH.

R ₂ j

-COOCE-,. -COOC ₉ H, -j ^: -COOC ₀ H _ς ·] -COOC.Hq j -COOC, H

-H

-H

-CH, -H

₇₁ -COOC ₉ H, OH

4 ά ο?

rOH o j-

R ₂ j

-H

-H J -CH.

-COKHCH ₂ OH - COMCH ₂ OH -COKHCH ₂ OCH

₂ OH ₂ OCH ₃

.COKHCH ₂ OCH ₃

•-H'

-CH ₃ Γ -Η

X -COKHCH ₂ OC ₂ H ₅

J-COMCH ₂ OC ₂ H ₅ .

\ -COKHCH ₂ OC ₄ H ₉

-H

CH.

, -MCOCH

3 I

-MCOC ₀ H ₁ -2

-MCOC ₃ H ₇ -K-CHO

CH ₂ OH

R ₂ j

-H-

-H -H

-K-COCHo -K-COC ₀ H ₁ --K-COCoE ₇

CH ₂ OH

CH ₀ OH

CH ₂ OH K-CHO t

-K-CHO t

CH ₃ - .._ CH ₂ OH

248 9 60 V

62 111/11

- 14 -

R ²  -Η -H -H X -N-COOCH., CH, -IT-COC, Η * CH ₃ -N-COC ₂ H ₅ ^G 2 ^H 5

* 2 I

-H

-H

CH.

-H

-H

R ₂ f -

--Ε

-H,

r __tr

-H

 -Η

Σ ', -. ',' · 2 ( 1) ('ΛΟι "] \ ΤΈΓ /" * ΧΧ CJ / Λ TJ * * Γ ^ / Λ1 \ Τυ / ** ΧΤ ί ^ ΧΤ i ^ TJ "Cf / Λ XJ ^ - LrUlMJl-On ₀ bU _o xlv · - UUiMIiOJI ₀ OiI ₀ UJ ^ AoUoJl. · \ C. J) ^λ ί ' ά ά ά J)' -H '-H'. '' ·. Σ. , ' -OUJnO ₂ U ₄ -UU ₃ H. -COHHCH-CH ₀ -SOoH ^ '^;

• CO-HH-CH ₂ CH ₂ CH ₂ CH ₂ -SO ₃ Η ^C1

- CO-HH-CH-CH ₂ CH ₂ -SO

r (1)

₂ CH ₂

CH-

-H

CO-HH-C-CH ₂ -SO ₃ H

(D

3 60 1

111/11

- 15 -

R ² '- ^CH 3 -CH ₃ X -COM-C ₂ H ₄ SO ₃ H ^ ¹ ^ GH. ^ CO-ITH-C-CH ₂ SO ₃ ^HCl)

-H

-CH-,

.GOO-CH ₂ CH ₂ -N

CH.

CH-

CH-

-COO-CH ₂ GH ₂ -I

CH

R ² -H -CH ₃ X -COO-CH ₂ CH ₂ -N ^ ^^ rt ττ ^C 2 ^H 5 - ^: '"' Jp ₃ ^ r -COO-CT ₂ CH ₂ -N ^ ^ CH _3.

R ²   -H -H ' . '' · X -COO-GH ₂ GH ₂ -N ^ -. ^G 4 ^H 9 -COO-CH ₀ GH ₀ -N ^ 2 2 \> CH ₃

R * Γ - H

CH.

-COO-CH ₂ CH ₂ CH ₂ -N

.COO-GH ₂ GH ₂ CH ₂ -N

CH.

-H

CH.

-COO-CH-CH ₀ -N

CH ₃ /

-COO-CH-CH ₀ -N. CHV

CH-

CH ₃

248960 1 ·. - ^1δ -

62 111/11

-H

CH.

Σ -CONH-CH ₂ CH ₂ -N

CH.

CH.

CH.

CH.

-H

CH.

.CONH-CH ₂ CH ₂ -N

-H

³ 3 ^Η 7

CH.

.CONH-CH ₂ CH ₂ -N

^R I -Ξ -, ..; .. -H .- χ ^G 4 ^H 9. -COM-CEpCHp-N ^ CH ₃ CH, -COIiH-CH ₂ CH ₂ CH ₂ -N ^ CH ₃

-CH

 3

.CONH-CH ₂₁ CH ₂ CH ₂ -N

CH.

CH.

• CONH-CH-CHp-N 3

, R ² I -CH,

1 - 17

-H

62 111 / IfI

.CH,

-CH ₃ -'CH ₃

? ^H 3 ·

COWH-C-CH ₀ -IT

CH ₃

•H

CH

-Ν®

-COO-CH ₂ -CH ₂ -N

(1) Since N-yinyl amide is not stable under acidic conditions.

are approaches that contain acidic substances, before,. the polymerization are neutralized, for example · with the above-mentioned inorganic or organic

Bases or basic comonomers. ,

Examples of preferred monomers which introduce units of the formula III into the novel copolymers are:

2T-vinylformamide,.

N-vinyl-N-methylformamide, ','. ...

N-Yinyl-1,2-diethyl-acetamide,

U-vinylpyrrolidone, '

Acrylic acid, alkali or ammonium salts of acrylic acid,

CH ₀ -CH-COOH-C-CH ₀ -SOOH or their alkali or ammonium

ιττ

salts

62 111/11

4 b y u w ι - is -

.CH ₃

CH ₂ = CH-CHCl-CH ₂ -CH ₂ -NY. , or

CH ₂ = CH-COO-CH ₂ CH ₂ -H *

\ CH ₃

To the best of our knowledge, the novel copolymers described above are novel with the exception of those in which a sulfo group or a sulfoalkylamidocarbonyl group or a salt is one of these groups (cf. US Pat. No. 4,048,077).

The novel copolymers described above can also be used for thickening or for gelling acid solutions, for. As in the process of Drucksäuerung as described in our co-filed patent application entitled "Water-soluble crosslinkable Polymerzusammen- \ translation, their preparation and their use" and in the same priority US patent application entitled "Water ¹ soluble Crbsslinkable Polymer Compositions Containing A Metal Compound, Their Preparation and Use, by Jeffery C. Dawson, Robert R. Mc-Daniels, and Lawrence Sedillo.

Ausführuhgsbeispiel

The following exemplary embodiments illustrate the preparation of the novel copolymers _o .

The abbreviations used in the examples and tables have the following meanings:

9 8 O

62 111/11

- 19 -

VIMA- '

JiIAS:

VSSNa:

  NMVA-:

VIItIPA:

MVIPA:

'Acrylamide' N-vinyl-N-methylacetamide

2-acrylamido-2-metiiylpropan-sulfonic acid,

where the exponent. ⁽

1. the ammonium salt,

2. the salt with dimethyl-β-hydroxyethylamine,

3. the potassium salt and /,

4. the sodium salt means acrylic acid 'methacrylic acid>

li-methylolacrylamide

Example of Vinyl Sulfonic Acid 'N-Metylol-vinylacetamide

Vinylacetamide ^x '

vinylformamide

Vinyl-methyl-formamide '' . , "H-vinylformamide Methy.lol-, H-methyl oil-vinylacetamide ^l vinylphosphonic acid.., Ammonium peroxydisulfate

A 'combination' of ammonium peroxydisulfate + dibutylammonium hydrochloride +

SG ₂ -Ch-NH-COOCH ₃

COOH azo-isobutyronitrile.

Example 1 . ';

In a 2 liter flask equipped with a water bath, stirrer, reflux condenser, dropping funnel and gas inlet are added 400 ml of deionized water and 17.7 ml of a 25% by weight aqueous solution

62 111/11 - 20 -

Submitted ammonia solution. With the introduction of a weak stream of nitrogen, 9.3 g of acrylamido-methylpropanesulfonic acid and, as soon as a clear solution is present, 60 g of acrylamide, 18.6 g of if-vinylpyrrolidone and 14.7 g of N-vinylformamide are added. The pH of the solution is 6.5. The batch is heated to 50 ^° C. and the polymerization is initiated by adding 5 ml of a 20% strength by weight aqueous solution of ammonium peroxodisulfate. After an induction period of about 10 minutes, the reaction, the temperature, starts up to 65 ^° C. and the mixture becomes viscous. The batch is then at 80 ⁰ G. warmed and held at this temperature for 2 hours. After cooling to room temperature, a highly viscous solution of the copolymer is obtained.

BeisDiel 2

500 ml of tert-butanol are placed in a 2-1 flask equipped with a water bath, stirrer, reflux condenser, dropping funnel and gas inlet tube, and 20 g of AMPS are suspended therein with stirring.

Then 2.2 l of ammonia gas are introduced and 65 g of acrylamide and 15 g of N-vinylformamide are added. While introducing a gentle stream of nitrogen, the mixture is warmed to 50 ⁰ C, and 1 g of azo-iso-butyronitrile added. After an induction period of a few minutes, the polymerization reaction starts. The temperature rises to 81 ⁰ G, un'd the polymer precipitates. The reaction mixture is kept for a further 2 hours at 80 ⁰ C, whereby a viscous suspension is formed. The polymer can be isolated by suction and dried at 50 ⁰ G in vacuo. However, it is also possible to isolate the polymer by distilling off the solvent under reduced pressure. The

62 111/11 - 21 -

The resulting polymer is a white, light powder which is readily soluble in water. The K-value according to Fikentscher is 148.

According to the above embodiments, it is also possible to prepare the copolymers of the following Tables Λ and 2:

Table I

Concentration of the monomer (% by weight) Reale Conc.

Ex. AM AS AMPS VIFA VIMI ¹ A VIMA VIA MAMMVIA MVIFA far. Cutsi's weighting no. Zus. Value medium %

_H Katy start £ ⁿ . lysa tempera ^weri; gate tur C

3 65 20 4 65 5 65 20 6 65. 7 65 20 8th 65 9 65 20 10 65 11 90.6 12 81.1 13 81.1 14 65 15 65 20 16 65 17 65 20

20 20 20

9.4 20

20

15 15

9.4

18.9

9.4

15 15

15 15

15

15 ·

15 15

155 What- 18

50

he 18 8.4 A 50 ι " a 129 ti 18 4.8 A 50 fV) IV) C 193 I! 18 8th A 50 I 149 ti 18 4.8 A 50  bam · 169 It 18 8.3 A 50 124 Il 18 4.9 A 50 154 It 18 8.0 B 50 122 It 21 10 B 20 he \ r \ 3 130 Il 21 9.8 B 20 1.11 ti 21 7.8 A 20 140 Il 18 8.3 A 40 208 .5 " 18 4.9 A 40 188 ti 18 8.2 A 40 199 Il 18 4.9 40 216 .5 "

Example no.

AS

Table 1 (Port setting)

Concentration of the monomer (wt .-%) -

Reak Conc ·

VIPA VIMPA VIMA. VIA MAM MVIA ¹ MVIi ¹ A wide. K- "ts ons- weight - add. Value medium %

Kata start lysa tempera value door G

• I C Ci C C

18 50

19 20 21 22 23 24 25 26

20

65 20

65 20

65 20

65 65 65

27 90.6

28 81.2 -

29 65 20

30 65 20

31 71.7

32 71.7 9.4

20 20

9.4

9.4

50

80

100

15

15

15 15

; 15

Λ 5;

18.9 18.9

15

9.4 9.4

borax

Il

60.5 Was- 25

51 25 203 201 223 223 182 187 130

These are Il Il Il Il Il Il Il Il

Il

, Il Il Il

25 25 18 18 18 18 18 18 21

21 10

21 2.1

4.2

7 7 10.1

7.9

8.0 8.3

A A A A A A B

B A A B B

23

23 23 40 40 40 40 40 40 35

ΓΟ-

35

40 w

40 ϊ

35 <

35 - *

Table 1 (continued)

Concentration of the monomer (wt .-%) Beispc AM AS

  Reak Conc. Kata- initial

AMPP VIPA VIMPA VIMA VIA MAM MVIA MVIPA far. Cationic- pH-pH lysa-tempera-

Zuso value medium % value gate door C

33 65 1 5 2 9.4 20 34 61 i 4 20 25 35 56.8 1 Third 20 30 36 65 1 5 2 20; '. 37 61 1 4 2 9.4 25 38 56.8 1 Third 4 20 3D ' 39 56.8 1 Third 20 40 71> 7 9th 41 71.7 42 65 43 65 15 44 ~ 80 20 45 70.5 20 _o 1 46 60 15 47 60 15

30 18.9

18.9

15

188 water 18 8th A 40 I 174 It 18 8.2 A 40 171 Il 18 8th A 40 144 It 10 8th A 40 cr> IV) 139 Il 10 8th A 40 _Λ 131 Il 10 8th A 40 \\ 139.5 Il <\ 10 8.1 A 40 Bo 188 ti 21.6 8.4 B 35 rax Il 149 Il 21.6 7.9 B. 35 151 Il 10 7.3 A. 40 143 H 10 7 A 40 Bo 92 ti 21.6 7.5 B 35 rax It 131 Il 21.6 7.5 B 35 186 It 17 4.8 A 40 172.7 ti 17 4.8 A 40

Table 1 (continued)

Ex. AT THE Au .2 48 60 20 .2 49 60 20 .2 50 60 51 51.8 13 52 51.8 vj 53 51.8 13

Concentration of the monomer (wt .-%).; .. Reak Conc

AMPF .VIPA VIMPA VIMA VIA MAM MVIA MVIFA far. K. tipns-

Zua. Value medium %

Kata- Startph Iysa- tempera-value door ° C

20

210.9 Water 17 17 4.8 A 40 198 Il 17 4.8 A 40 VJlV 164 Il 10 4.7 A 40 132.8 Il 10 4.8 A 40 I 131.5 It 10 4.8 A 40 5 117.4 Il 4.8 A 40

IV) VJl

Table II

Concentration of monomers (% by weight)

Ex. AT THE AS AMPS VIFA VIMFA - VIM 54 65 20 , VJL 15 55 65 20 15 - 15 56 65 20 15 57 65 20 15 58 65 20 59 65 20 60 65 20 61 60 20 15 62 60 20 15 63 6o 20 VJI 64 60 20 15 65 60 20 15 66 60 20 VJL

_Reak _ _{Konz # Kata} _

far. Cationic, pH-lysa-tempera-Zus. Value medium % value gate door C

15

5 5

5 5

5 5

148 178 tert-butanol Il 20 20 9.1 9.1 C O 142 Il 20 9.0 G 176 Il 20 9.1 G 131.5 Il 20 9.2 G 157 Il 20 8.8 G 141 Il 20 8.9 G 144.-5 Il 17.5 9.0 G 179.5 Il 17.5 9.6 C 177 Il 17.5 9.3 G 181.5 Il 17.5 8.9 G 146.2 It 17.5 8.6 G 182.7 Il 17.5 8.9 G

50 I C O O O in tn in ro σ% I C C C 50 50 cn ro 50 -1 50 50 - * 50 50 50 50

248 960 1 .. "'. ^62111/11

Example 67 -.

In a 500 ml flask equipped with a water bath, stirrer, reflux condenser, dropping funnel and gas inlet, a solution of 0.23 g of sorbitan monolaurate, 1.09 sorbitan monostearate, 0.14 g of sorbitan monooleate and 3.61 g polyoxyethylene sorbitan monostearate in 56.4 g of a straight-chain paraffinic hydrocarbon fraction (Norpar 13 from Exxon) submitted. While introducing nitrogen, the solution is heated to 6O ⁰ C. , -.- '.

In a separate vessel, dissolve by 33.6 g. Acrylamide 5.4 g AMPS, 6.6 g N-methyl-N-vinylacetamide, 6.6 g ⁽ N-vinylformamide and 7.8 g vinylpyrrolidone) in a mixture ¹ of 78.8 g of deionized water and 2.6 ml of 10% strength by weight sodium hydroxide solution: a monomer solution prepared, the pH of this solution being 7.4. The monomer solution is mixed with 23 mg of 2,2- ^F -A2O-bis- (2-amidinopropaQ hydrochloric acid and then added dropwise with vigorous stirring to the initially introduced organic emulsifier solution to give a milky white emulsion. As soon as the temperature of the mixture has risen again to 60 G, the stirring speed is increased to about 60 revolutions per minute. the emulsion 97 is reduced. After an induction time of 10 min., a temperature rise begins * at about 80 ⁰ C is transparent, and the stirring speed is increased. Die.Temperatur continues to rise up to max. G. After the mixture cooled down to 80 C is stirred at this temperature for 2 hours obtains a stable emulsion containing 30% by weight of active polymer,

248 9 60 v. 28-

Example 68

In a 1-1 polymerization vessel, 6? g of a deodorised Kerosinfraktion with a boiling range 'from 190 to 240 ⁰ G (Exsol D, sales product of Esso Chemie, Germany) heated to a temperature of βθ ⁰ C. With slight stirring, 0.27 g of sorbitan monolaurate, 1.3 g of sorbitan monostearate, 0.17 g of sorbitan monooleate and 4.3 g of polyoxyethylene sorbitan monostearate are successively dissolved. With further gentle stirring and introduction of a nitrogen stream, the solution is then heated to 60 ⁰ C. In a second vessel are dissolved in 94 ml of water, 6.4 g of AMPS, 44.8 g of acrylamide, 9.2 g of vinylpyrrolidone and 10.6 g of N-vinyl-formamide with stirring. The solution thus obtained is adjusted to a pH of 8 to 10 by the dropwise addition of 10% strength by weight aqueous sodium hydroxide solution and treated with 0.1 × of ammonium persulfate. The aqueous monomer solution thus obtained is added dropwise with rapid stirring through a dropping funnel into the organic emulsifier solution initially introduced and emulsified. The polymerization reaction starts after about 30 minutes with an increase in the temperature. In the course of 15 min. "The temperature rises to 80 to 90 ⁰ C. Subject decay of the polymerization wird.die solution stirred for a further 2 hours at 80 ⁰ C · A stable emulsion having a polymer content of 30 wt .-%. The molecular weight of the polymer is 95,000.

'Example 69

1 »85 g of sorbitan monostearate are dissolved in a technical isomeric hydrocarbon mixture having a boiling range of 200 to 240. ⁰ G. This solution is dissolved in a 2-1 reaction

248 9 60 ι: ₂₉ - ^62111/1 ; ¹

tion piston, loaded with stirrer, thermometer and gas, inlet tube, submitted. \

In a separate vessel, a monomer solution is then prepared by dissolving .25 g of acrylamide, 3.7 g of acrylic acid and 9.2 g of N-vinylformamide in 40 ml of deionized water, and the pH of this solution by addition of an aqueous 20 wt With vigorous stirring, the aqueous monomer solution is slowly run into the organic sorbitan monostearate solution and then the air in the reaction vessel is displaced by nitrogen. · '

After addition of 0.07 g of 2,2'-azo-bis-isobutyronitrile, dissolved in acetone, the emulsion is slowly added with stirring to 60 ^Q G. After heating for 2.5 hours, the polymerization is complete and a stable emulsion of the copolymer is obtained.

Example 70 '-'

67 g of a technical isomeric hydrocarbon fraction having a boiling range of 200 bis.240 ⁰ C are introduced into a polymerization vessel, and 1-1-auf'60 ⁰ G heated. While stirring, 0.27 g of sorbitan monolaurate, 1.3 g of sorbitan monostearate, 0.17 g of sorbitan monooleate and 4.3 g of polyosethylene sorbitan monostearate are dissolved in succession.

In a separate vessel, 12.8 g of YIMA, 39.8 g of acrylamide, 12.0 g of vinylpyrrolidone and '6.6 g of IJ-YinyIformamid are dissolved with stirring in 94 ml of water. The pH of this solution is adjusted dropwise by addition of 10% by weight aqueous Itfatriumhydroxylösung to 8 to 10, and then

248 9 60 1. -30-, ^{δ2111 / 11}

0.1 g of ammonium persulphate are added. This monomer solution is then added dropwise with vigorous stirring through a dropping funnel into the initially introduced organic emulsifier solution and emulsified therein. The polymerization reaction starts after about 30 min., Over the course of 15 min., The reaction temperature rises to 80 to 90 ⁰ C. After the reaction has subsided, the solution is stirred at 80 ^° C. for a further 2 hours. This gives a stable emulsion having a polymer content of 30 'wt -.% · The molecular weight of the polymer is 95,000. ,

According to the embodiments 68 and 70, the products of the following Table III can also be prepared, which can also be used as valuable friction reducers for aqueous acids. -.

AS AMPS. VP , table ill K value, AT THE 20 15 ^ / Z-el. 148 ' 65 20 15   -. 6.59 165.8 65 20 15 10.05 163 65 20 9.36 186 65 20 15 5 HMA 17.27 172.7 60 2 NC '15 5 IIMA 11.97 169.4 60 .20 15 5 SMVP 11.0 1 51, 2 60 20 15 5 IMVP 164 60   20 15 5 HMVP 9.47 210.9 60 20 15 5 HMA / * 35.0 193 60 .8 13,2 - 30 HMVP 24.43 132.8 51 .8 13,2 30; 5 HMA 4.66 131.5 51 .8 13,2 30 5 MüVA / 4.53 117.4 "" 51 HMVP 3.41

24 8th 9.6 0 1 5 , - 31 62 -, · 111/11 K value 32 AS AMPS VF 5 H / rel. 173 16 AT THE 13.2 30 5 BMA. 12.16 162 4, 51 * 8 13.2 30 5 nmva 9.1 163, o '·' 51.8 13.2 30 '5 UMVP 9.3 · 207 51.8 20 15 20 NMA 31.44 , 119, 60 13.2 30 NMVP '3.57. 204 51.8 10 > '. 5 VIP   29.3 65

All quantities in Table III are parts by weight.

Example 71

, 'ι.

In order to demonstrate the friction-reducing property of the copolymers according to the invention, flow tests were carried out with 7.5% strength by weight hydrochloric acid once without and once with an addition of the copolymer according to the invention prepared according to Example 1.

To carry out the experiment, a tube loop was used in which the fluid is pumped through a series of tubes of known length and known diameter at a certain flow rate. In this case, the hydromechanical pressures are measured at both ends of a given, defined RohrabSchnitt. Since one knows the flow rate and the pressure differences at the relevant pipe section, it is thus possible to plot the friction pressure of various fluids as a function of the flow rate of the fluid in the pipe.

62 111/11

248960 j - ³² -

The first experiment was carried out with 208 l of 7.5% by weight hydrochloric acid containing 760 ml of a commercial corrosion inhibitor, pumping speeds of 38 to 57 l / min using a 0.925 cm internal diameter pipe, 19 to 170 1 / min using a tube having an inner diameter of 1.25 cm and 19 to 454 l / min using a 2.66 cm inner diameter tube. According to this test series, 224 g of the copolymer prepared in Example 1 were added to the 7.5% strength by weight hydrochloric acid, corresponding to a copolymer concentration of 0.1% by weight in the acid. The flow experiment was repeated with this polymer-containing acid.

Example 72

In order to demonstrate the acid solubility of copolymers according to the invention, they were subjected to the following experiment in comparison with commercial friction reducers:

200 ml of 15% strength by weight hydrochloric acid were introduced into each of the three 225 ml tubes. The acid in vessel 1 was then made 2.0 g of the polymer of the invention of Example 2, in vessel 2 was added 2.9 g of a commercial friction reducer emulsion LPR-1 and in vessel 3_ was added 3.2 g of a commercial friction reducer emulsion LPR-1. 2 added. The commercial products LPR-I and LPR-2 are copolymers of acrylamide and acrylic acid with molecular weights of 500,000 to 2,000,000. The polymer contents of the emulsions LPR-1 and LPR-2 are unknown, but it can be assumed that there are differences between the two products with respect to the amount of the active copolymer, the comonomer ratio of the polymers

248 9 60 1 .33- ^6Z

and the type of emulsifier. The samples in the three vessels was 24 hrs. At 60 ⁰ G erwärmt. tray this time, the solution in the vessel 1 which contains Cppolymerisat the invention, after, still completely clear, the copolymer thus completely soluble. In contrast, vessels 2 and 3 each had white precipitate pots formed. The excreted plague were sucked off and with. Was-, .ser and then washed with methanol. Thereafter, the Pilter residues were dried in vacuo at 40 ⁰ C over Hacht. The amounts obtained are shown in the following table, IY. ., '.

Table IY

ρ. , "he." initial weight of the % insoluble weight, insoluble deposit

deposition

Inventions according to the copolymer 2 , 0 g ⁺ 0 for 5 G 0 6 G LPR-1 - Emu1si on 2 »90 1 , 82 G 39, 6 G LPR-2 emulsion 3 20 0  25-,

⁺ The stated weight, in these cases refers to emulsion, not to pure polymer.

Example 73 ''. ,

Pure acid is selected for natural gas drilling in West Texas. The hole has a production interval between a depth of 1100 to 1120 meters. The sole temperature

248 9 50 1

62 111/11

- 34 -

in this interval "is 43 ⁰ C, the permeability of the formation averages 0.15 md (millidarcy), the pipe diameter is 6.0 cm, and the spontaneous productivity of the well" before treatment is about 168 m of gas per day.

The pressure acidification fluid to be used is prepared by first mixing 3785 l of 28% strength by weight hydrochloric acid with 35960 l of fresh water and then adding the resulting dilute acid 79.5 l (0.2% by weight) of the polymers prepared according to Example 3. Emulsion adds. The resulting fluid is injected into the well at a rate of 1589.8 l / min under a pressure of 310.5 bar. After 25 minutes, the pumping is complete and the well is sealed to remove the acid Opportunity to react with the rock.

After 00 minutes, the pressure at the head of the bore is relieved and the delivery rate ντ / reverts. A measurement of the delivery rate results in a significant increase in the productivity of the well,.

Claims (5)

Erfindungsansprueh. ' ~. '( 1 '2 ' 'wherein R, R and X have the meanings given above, copolymerized in the range of pH 4 to 12 under initiation by radical generator or high-energy radiation. 1, A process for the preparation of a water-soluble.Copolymerisate, which is composed in random distribution to 5 to 50 wt .-% of units of the formula i -GH ₀ -GH-, ', - From 10 to 95% by weight of units of formula II -CH ₀ -GH- ' , "GÖ-m ₂ .-,. ' ^: ." (1I) and 0 to 85 wt -.% Of units of formula III. -CH ₂ -C- •. (III), ' '/ · Ι .- .- · ·. .- .. '. '. ' wherein R is hydrogen, methyl and hydroxymethyl and R is hydrogen or methyl and X is cyano, carboxyl or its alkali or ammonium salts, alkoxycarbonyl having 1 to 6 carbon atoms, hydroxyalkoxycarbonyl having 1 '' to y carbon atoms; IT-methyl oil amido-carbonyl of the formula HOCHpEH-GO-, whose methylol group may optionally be etherified with alkanols having 1 to 4 carbon atoms; Alkanoylamino of 1 to 4 carbon atoms which may optionally be H-substituted by methylol or alkyl of 1 to 4 carbon atoms; Pyrrolidonyl (1): 248 9 60 1 ._36 - "- ' ^{6iM11 / 11} phenyl; pyridinium; the phosphonic acid group or its alkali or ammonium salts; a radical of formula IV -COOCH ₂ CH ₂ -OPR ³ (IY), wherein R and R are the same or different and are alkyl having 1 "to 4 carbon atoms; a radical of the formula V. R ³ wherein R · and R have the meanings given above, and ρ is a number from 1 to 4; or a radical of the formula VI R ⁶ R ⁶ (VI) wherein R and R are the same or different and are alkyl of 1 to 4 carbon atoms and ρ is a number from 1 to 4; and the corresponding quaternized groups corresponding to the formulas V and VI, characterized in that 5 to 50 wt. % of an optionally N-substituted vinylformamide of the formula Ia CH ₂ = CH-NC 1 (Ia), 10 to 95 wt .-% of acrylamide and 0 to 85 wt .-% of an ethyleniseil unsaturated monomer of the formula. IIIa. 248 9 60 1 - * - ^6a - ^{1l1 / 11} ' R ^2: · _ - ^ ^; , ι CH ₂ = CZ, (Ilia), Method according to item 1, characterized in that 5 to 30% by weight of the vinylformamide of the formula Ia, 50 to 80% by weight of acrylamide and 1 to 60% by weight of the monomer of the formula IIIa copolymerized. , · 3. The method according to any one of the items 1 or 2, characterized in that one comprises an ethylenically unsaturated monomer , the Pormel HIa, wherein the Σ is carboxyl, alkanoylamino having 1 to 4 carbon atoms, which may optionally ¹ with H-substituted by / methylol or alkyl having T-4 carbon atoms, γrrolidonyl- (1) or a radical of the above and defines formulas V and VI wherein the carboxyl group may also be present as sodium, potassium or ammonium salt. , , 4. Method according to one of the items "1 to 3, characterized in that the resulting copolymer or the resulting aqueous solution of the copolymer is added so much water that a 0.5 to 6 wt .-% solution is obtained" < 5. The method according to one of the items 1 to 3, characterized. in that the polymerization in the aqueous phase a water-in-oil emulsion is performed.