JPH0196279A - Acidified crashing fluid containing high molecular weight poly(vinyl amine) for tertiary oil collection - Google Patents

Abstract

PURPOSE: To provide the fluid which has excellent high temp. viscosity stability and is prepd. by incorporating a poly(vinylamine) which has an extremely high mol.wt. and of which more than half is hydrolyzed at a specific ratio into an aq. hydrochloric acid soln.

CONSTITUTION: This objective fluid is prepd. by incorporating the poly(vinylamine) which has an average mol.wt. ≥10⁶ and of which ≥50% is hydrolyzed at the ratio of 0.2 to 2 wt.% into the aq. 5 to 28% hydrochloric acid soln. and has viscosity of FANN35 of 10 to 100 cPs at 300 rpm and 510 sec^-1 and with an R₁B₁ sensor. The poly(vinylamine) is obtd. by dispersing, for example, an aq. soln. of a water-soluble N-vinylamide monomer into a hydrocarbon liquid by the effect of a surfactant and subjecting the dispersion to polymn. by an antiphase emulsification polymn. method to obtain an emulsion of the poly(N-vinylamide), then separating the N-vinylamide and further hydrolyzing the same.

COPYRIGHT: (C)1989,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to tertiary oil extraction (
The present invention relates to use as a composition for enhanced oil recovery.

Water-soluble polymers such as poly(N-vinylamide) often require high molecular weights to provide acceptable high performance for their applications. Low to medium molecular weight poly(N-vinylformamide) and poly(N-vinylacetamide) have been prepared by conventional solution polymerization in water and alcohol using oil- and water-soluble initiators. However, high molecular weight poly(N-vinylamide) is difficult to produce by conventional solution polymerization because the polymerization product obtained under practical conditions is a gel that is difficult to handle. In addition, problems with high solution viscosity and poor heat transfer preclude synthesis on a commercial scale.

However, poly(vinylamide) and poly(vinylamine) have very high molecular weight (>106)
It was thought that this could be improved by producing and using a homopolymer of

U.S. Pat. No. 4,500,437 describes N-vinylformamide and N-vinylformamide prepared by reverse-phase emulsion polymerization.
- Acrylamide copolymers and terpolymers containing vinylacetamide are disclosed in Examples 67-70, of which those shown in Examples 68 and 70 have a molecular weight of less than 100.000 i.e. <10" Example 20 discloses the production of poly(vinylformamide) by solution polymerization.

U.S. Pat. No. 4,421,602 states that 90-1
0 mol% copolymerized vinylamine units and 10-90 mol%
A linear basic polymer containing copolymerized N-vinylformamide units is disclosed. This patent teaches that the polymer is made by solution polymerization in water, a water-soluble solvent, or a mixture of water and a water-soluble solvent;
The examples disclose such solution polymerizations. It is suggested there that the polymerization is carried out in water-in-oil emulsion polymerization even in water-immiscible solvents, but no such examples are given.

U.S. Pat. No. 4,018,826 discloses that vinyl acetamide' is polymerized using a furinyl radical polymerization catalyst, and that the poly(vinylacetamide) is hydrolyzed by contacting the poly(vinylacetamide) with an aqueous solution of mineral acid. The preparation of poly(vinylamine) salts of the corresponding mineral acids by converting them into the desired amine salts is disclosed.

It is believed to be a poly(vinylamine) product with a molecular weight of about 3.000 to about 700,000 (4.000 to 1,000,000 for the salt product).

U.S. Pat. No. 3,558,581 discloses that N-vinyl-N-
Corresponding polymers of methylamine are disclosed.

U.S. Pat. No. 3,597,314 discloses that 60 to 100 formic acid radicals are separated from the polymer by acid hydrolysis.
% of N-vinyl-N-methylformamide is disclosed. There is no description regarding reverse phase emulsion polymerization.

British Patent No. 2.152.929 describes the thermal decomposition of N-(alpha alkoxyethyl) formamide in the gas phase.
The purpose is to produce N-substituted formamide for the production of N-vinylformamide. N-vinylformamide is
Bulk polymerization, solution polymerization using aqueous or organic solutions, or emulsification in the presence of an azo compound polymerization initiator alone or together with monomers conventionally used for the production of water-soluble polymers suitable for the production of flocculants. This suggests that it can be polymerized. The poly(vinylformamide) thus obtained is hydrolyzed under acidic or basic conditions to form a cationic polymer of poly(vinylamide).

Po1y (viny
lamine hydr-roch for 1de),
5ynthesis and utilization
for the Preparation of Wa
ter-Soluble Polymeric Dyes
r J, Am, Cham Soc, J, 98
: 19.5996 (1976) discloses the preparation of N-vinylacetamide and its solution polymerization followed by acid hydrolysis to form poly(N-vinylamine hydrochloride).

Representative of many prior art related to water-in-oil emulsion polymerization of water-soluble monomers is U.S. Pat.
．． No. 749, No. 3.278.506, No. 3.28
No. 4.393, No. 3.957,739, No. 3.9
75. :341, 4.078.133 and 4,312.969.

rSynth by R.H. Summerville et al.
esis of N-vinyl Acetamide
and Preparation of SomeP
Polymers and Copolymers, Pol
ym, Repprints, 24°12 (1983)
attempted inverse emulsion polymerization of N-vinylacetamide with a sodium persulfate initiator in water and cyclohexane using Igepal surfactant, but this proved unsuccessful. ing.

U.S. Pat. No. 4,217,214 states that approximately 5×1
Polyvinylamine hydrochloride with a molecular weight of 0.06 or higher is described as being particularly effective as a flocculant in wastewater systems. The examples show the use of poly(vinylamine) hydrochloride having a molecular weight of 2XLO', and the poly(vinylamine) hydrochloride used is described in U.S. Pat. No. 4,018,826. It has been revealed that it was prepared in a similar manner.

U.S. Pat. A linear basic polymer powder having units of the formula -CHz-CH(NHx)- and having a Fitzkencher's value of lO to 200 is disclosed, which is produced by eliminating formyl groups. ing.

JP-A-61-141712 discloses a process in which an aqueous solution of N-vinylcarboxylic acid amide is dispersed in a hydrocarbon type dispersion medium using an oil-soluble polymer dispersion stabilizer, and then radical polymerization is performed. A method for making N-vinylcarboxylic acid amide polymers is described.

According to the present invention, extremely high molecular weight poly(N-vinylamide) can be produced by reverse phase emulsion polymerization.

The present invention relates to an aqueous solution containing 10 to 90% by weight of a homopolymer of N-vinylamide having the following formula % (wherein R and R1 are hydrogen or CI""' C4 alkyl group) ~70% by weight is C6~cr,
The homopolymer consists essentially of an emulsion colloidally dispersed in a hydrocarbon liquid consisting of an alkane and also a xylene compound (toluene and xylene in the case of R-alkyls) and has an average molecular weight of at least 108. and the emulsion was 15% solids, 50 rpm Brookfield (7,9 sec-'
) and a reverse phase homopolymer emulsion having a viscosity of 1 ocps under conditions of 20°C.

The method for producing reverse phase or water-in-oil emulsions is
Water-soluble N-vinylamide 10 to 90 represented by the above formula
% by weight of the aqueous solution containing the hydrocarbon liquid using a surfactant with an HLB value of 4 to 9, preferably at a monomer-containing aqueous solution to hydrocarbon liquid weight ratio in the range of 1:2 to 2:1. It consists of dispersing colloidally in a hydrogen liquid and polymerizing the monomer using an azo type free radical initiator.

The resulting extremely high molecular weight polymer emulsion is
15% solids, 60 rpm Brookfield and 2
It has a low viscosity in the range of less than 2 to 10 cps under 0°C conditions, which solves the problem of increased solution viscosity that occurs when polymers are produced by solution polymerization.

Moreover, low viscosity homopolymer emulsions are easy to handle and can be used directly.

One such use for vinylamide homopolymer emulsions involves hydrolyzing the homopolymer, preferably as an emulsion, with an acid or base catalyst to at least l
One example is to produce a vinylamine homopolymer having an average molecular weight of O6. When mineral acids are used in the hydrolysis step or in the acidification of basic hydrolysis products, poly(vinylamines) are obtained as salts of such acids.

Extremely high molecular weight water-soluble poly(N-vinylamide)
and derived poly(vinylamine) for water treatment, tertiary oil extraction,
and has applications in the paper manufacturing field. For example, derived poly(vinylamine) can be used as an important component in oil field chemical compositions such as drilling mud compositions, drill hole cements, finishing fluids, and acidified fracturing fluids.

Low concentration salt solution e.g. 0.5-1% in 2% KCQ solution
Solution rheology of poly(vinylamine) at concentrations (1 to 1
Thickening efficiency and viscosity response to shear rates in the range of 0,000 sec-' are important for many oilfield chemical composition applications. Very high molecular weight polymers have better thickening properties and rheology.

When the poly(vinylamine) of the present invention is used in tertiary oil extraction (EOR), compositions with improved viscosity stability at 90'C and improved viscosity retention in seawater are obtained. Most commercially available polymers do not perform well under either of these conditions.

Hydrolyzed polyacrylamide does not work in seawater solutions at elevated temperatures because the presence of calcium ions in seawater causes precipitation of the polymer. Xanthan polymers are not sensitive to calcium ions. However, at high temperatures the polymer chains unravel and lose their viscosity.

Generally, such EOR compositions have an EOR of about 1000 to 2
000 ppm of poly(vinylamine), 7.9 sec-' (60 rpm) and 90
It has a Brookfield viscosity of 10-20 cps at °C. The very high molecular weight vinylamine polymers of the present invention can be used at elevated temperatures and calcium salts (i.e., a set of conditions when used for EOR thickening at elevated temperatures).
It appears to show improved stability.

When used in acidified fracturing fluids, the poly(vinylamine) of the present invention exhibits improved viscosity stability in concentrated hydrochloric acid solutions below 70°C. Most commercially available cellulosic polymers currently used in this field cannot be used under these conditions due to cleavage of the polymer backbone. Such fluids contain about 0.2-2% poly(vinylamine) and 5-28%
% hydrochloric acid aqueous solution, and 300 rpm.

510 sec-' and 10 by R+B+ sensor
It has a FANN35 viscosity of ~100 cps.

The present invention also provides a method for activating an oil well by acid fracturing using an aqueous acid solution, in which the acidic solution is injected into the oil well under pressure sufficient to fracture the formation and brought into contact with the formation. The acidic solution contains a vinylamine homopolymer having a molecular weight of 106 or more as a thickening agent.

Still other embodiments of the invention include drilling mud compositions that exhibit good rheology. Such drilling mud compositions consist of 0.1-1% by weight poly(vinylamine), 0-10% by weight salt, and 0.5-5% by weight clay dispersed in water.

In accordance with the present invention, a finishing fluid is provided that exhibits not only high temperature viscosity stability but also high viscosity in saturated brine solutions. A typical finishing fluid consists of a saturated salt solution containing 0.2-2% by weight poly(vinylamine).

The present invention also provides that retention, drainage rate, and cohesiveness can be increased by adding the poly(vinylamine) of the present invention to the pulp material in a papermaking process in which the pulp material is deposited to form a nonwoven sheet. .

A poly(N-vinylamide) having a molecular weight of at least 106, preferably from 3x106 to 15x106, is prepared using an inverse emulsion polymerization process by reacting the following compositions under an inert atmosphere: Ru.

1. A water-soluble N-vinylamide monomer, 2. Water, 3. A hydrocarbon liquid, 4. A wood-in-oil emulsifier, and 5. An N-containing free radical initiator. (In the formula, R, R' are hydrogen or 1 to 4, preferably 1
10 to 90% by weight of a water-soluble N-vinyl amide having ~2 carbon atoms (representing an alkyl group, especially a methyl group);
Preferably the content is 50 to 70% by weight.

The weight ratio of monomer-containing aqueous solution to hydrocarbon liquid can vary widely depending on the monomers used, but is preferably about 1=
2-2:l.

Hydrocarbon liquids suitable for use in the present invention are those that are water immiscible and do not significantly dissolve the monomers in the presence of water. Examples of such hydrocarbon liquids include acyclic and cyclic Cs~C+o alkanes such as hexane, octane, decane and decahydronaphthalene (decalin), as well as certain compounds for N-vinylacetamide. Examples include aromatic hydrocarbons and the aromatic hydrocarbons toluene and xylene. Ethylbenzene and tetrahydronaphthalene (tetralin) are contemplated as functional equivalents to toluene and xylene when R in the monomer formula is an alkyl group. Preferred hydrocarbon liquids are C6-C8° acyclic alkanes.

The stabilizing system consists of suitable emulsifiers or surfactants having a lignophilic-lipophilic balance (HLB) value of 4 to 9, preferably 4 to 7.5, including sorbitan fatty acid esters such as sorbitan monostearate, oleate, etc. , laurate or palmitate; polyoxyethylene sorbitan fatty acid esters, i.e. reaction products of 4 to 40 moles of ethylene oxide and 1 mole of the above-mentioned sorbitan fatty acid esters; polyoxyethylene sorbitol esters of fatty acids; and mixtures thereof. . A suitable amount of surfactant is 5-20% by weight based on the aqueous monomer-containing solution. - The free radical initiator should be one of the azo compounds well known in the polymerization art, such as 2,2'-azobis(imbutyronitrile);
2,2'-azobis(2-amidinopropane) hydrochloride;
Examples include 4.4'-azobis (4'-cyanopentanonic acid). It has been found that persulfates and hydrogen peroxide are not suitable for practicing the invention.

Redox catalyst systems can also be used with azo initiators using reducing agents typically used in the art. The amount of free radical initiator may vary widely depending on the reaction temperature, polymerization rate and degree of polymerization desired, but is preferably between 0.001 and 0.5 of the monomers used.
The range is mole %.

Polymerization is usually carried out under an inert atmosphere, preferably nitrogen. The reaction temperature is preferably in the range of 40-60°C. High temperatures, ie >60° C., can lead to adverse side reactions for the polymer, such as crosslinking or chain transfer. Lower temperatures are not practical because the reaction time will be longer.

The homopolymer product is isolated from the emulsion by adding a flocculant and filtering. The precipitated product is then washed and dried.

Generally, polar organic solvents such as acetone, which are good solvents for surfactants but not good solvents for polymers, are used to flocculate the polymers. The precipitated polymer is filtered and washed to remove surfactant. The very high molecular weight, dry and purified polymer is finely powdered and water soluble.

The vinylamide homopolymer product is hydrolyzed in the presence of an acid or base to a vinylamine homopolymer having an average molecular weight of at least lo6. More preferably, 1
．． A vinylamine homopolymer having a molecular weight of 8xlO' to 9x101 or more is obtained. Vinylamine polymers suitable for use in acidified fracturing compositions include about 50
% or more, preferably about 90% or more, about 99+%.

Suitable acids for use in hydrolysis include mineral acids such as hydrobromic acid, sulfuric acid, phosphoric acid and perchloric acid; and organic acids such as trifluoroacetic acid and methanesulfonic acid.

Bases that can be used include alkali and alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide: and quaternary ammonium hydroxides such as tetramethylammonium hydroxide. The amount of acid or base required can vary widely depending on the desired freshness of the hydrolysis and reaction conditions. Approximately 1 to 3 equivalents of acid or base per equivalent of polymer are suitable to effect substantially complete hydrolysis.

Hydrolysis can be carried out in a variety of solvents such as water; liquid ammonia; alcohols such as methanol, ethanol, impropatol and L-butanol; amines such as methylamine, dimethylamine, ethylamine, etc.; and hydroxyamines such as ethanolamine. . However, it is preferred to simply add the aqueous acid or base solution to the water-in-oil emulsion.

The temperature of hydrolysis may range from 20 DEG to 200 DEG C. depending on the polymer employed and the type of hydrolysis. In general, hydrolysis is more important than poly(N-vinylacetamide).
-vinylformamide).

Therefore, the hydrolysis of poly(N-vinylformamide) can be carried out under milder conditions, ie, at lower temperatures and shorter reaction times, than the hydrolysis of poly(N-vinylacetamide).

The preferred temperature range for base hydrolysis is 70-100°C, which is lower than the acid or base hydrolysis of N-vinylacetamide, which ranges from 110-200°C.

The hydrolyzed polymer product thus obtained consists of repeating units containing free amino groups having the formula % in the case of basic hydrolysis; and the formula % in the case of acid hydrolysis. It consists of an amino group-containing unit having the formula % (wherein X- represents an anion corresponding to the acid used in the hydrolysis).

The poly(vinylamine) is preferably isolated in salt form to prevent atmospheric carbon dioxide adsorption. The polymer salt is isolated by acidifying the hydrolysis mixture to precipitate the polymer. The precipitated polymer, usually a gum, is redissolved and then reprecipitated from methanol to yield a fibrous material.

The product of the invention is a high molecular weight poly(N-vinylamide)
, especially poly(N-
vinylformamide) and poly(N-vinylacetamide) with a molecular weight of 1.3 to 5 x 10@, and derived poly(vinylamine) and poly(vinylamine) salts.

These polymeric materials (which may also contain up to 25% by weight of copolymerizable monomers such as acrylamide and N-vinylpyrrolidone) can be used in water treatment as long as they retain sufficient water solubility. It is particularly useful as a flocculant, retention agent, and thickener in the tertiary oil extraction and papermaking fields. These polymers are also used as corrosion inhibitors, photographic agents, surfactants, protein hardeners, and ion exchange resins.
It is also used as a compounding agent in the production of medicines, food dyes, herbicides, and agricultural chemicals.

For acidified fracturing fluids in oil well activation reservoirs, such compositions contain 0.2 to 2%, preferably about 0.5%, of the present invention as a thickener in a 5 to 28% aqueous hydrochloric acid solution. The molecule consists of poly(vinylamine) and optionally 0.5-1% crosslinking agent based on the weight of the poly(vinylamine).

Suitable crosslinking agents include, for example, organic titanate complexes, shrimp chlorohydrin, hexamethylene diincyanate,
Examples include glyoxal, butylene diol diacrylate, terephthalaldehyde and glutaraldehyde, of which the latter two are particularly preferred when the pH is low. This fracturing fluid composition is 300 rpm, 510
lO~100cp for sec-' and R+B+ sensors
It should have a viscosity of FANN35 of s.

These acidified fracturing fluids are injected under pressure into the well and into contact with the formation. The pressure at this time must be sufficient to fracture the formation.

Example 1 This example demonstrates the production of very high molecular weight poly(N-vinylformamide) by reverse phase emulsion polymerization.

Sorubitan monolaurate (SPAN60 surfactant, HLB4.7.2.5g), 909
) and the resulting solution was transferred to a reaction kettle.

The reactor was purged with nitrogen and maintained at a nitrogen atmosphere throughout the polymerization. A solution of N-vinylformamide (15 g in 30 g) was degassed and heated to 2.5 m with vigorous stirring.
It was added to the reactor at a rate of Q1 minutes.

(N-vinylformamide was purified by vacuum distillation at 70° C. and 1 torr before use).

While heating the reaction mixture to 50°C, 0.059% of the 2,2'-azobis(2,4-dimethyl-pentanitrile) initiator
) was prepared. After 3 hours at 50° C. under stirring, a stable polymerized emulsion was formed with a viscosity of 3 cps. The solid polymer product was recovered by adding acetone to break the emulsion. The isolated N-vinylformamide homopolymer had a molecular weight of 6.7×10 6 as determined by light scattering and a viscosity of 21,000 cps as a 5% aqueous solution.

Example 2 Vinylformamide homopolymer of Example 1 (10 g)
was dissolved in water (990 g) and then mixed with 50% aqueous sodium hydroxide (11.39 g). The resulting mixture was heated at 80°C for 8 hours under nitrogen atmosphere.

Concentrated hydrochloric acid was added to the reaction mixture until the polymer precipitated.

The acid solution was decanted. The precipitated polymer was redissolved in water and reprecipitated with methanol. Vinylamine homopolymer hydrochloride had a viscosity of 400 cps as a 1% aqueous solution.

Example 3 This example demonstrates the production of very high molecular weight poly(N-vinylacetamide) by reverse phase emulsion polymerization.

N-vinylacetamide is described in US Pat. No. 4,018,826. Manufactured in accordance with the law. N-vinylacetamide was purified as follows: crude N-vinylacetamide (l
J29) was distilled at 70-74° C. and 1 torr for 7 lacs. 2/3 of the material is distilled to a ratio of 70:30 N-
A vinylacetamide/acetamide mixture was obtained.

This mixture (100 g) and toluene (6009) were placed in a 1000 m (2 m) beaker and the resulting mixture was stirred well. The toluene solutions were combined and washed with 25 g of brine. The yellow nophrine solution was discarded. The toluene solution was then extracted four times with 130 iff of water. The aqueous solution was washed with 25 g of brine.
Re-extracted with 5 mQ of methylene chloride. The methylene chloride solution was discarded. The aqueous solution was saturated with sodium chloride and extracted four times with 330 m4 of methylene chloride. After removing methylene chloride under reduced pressure, 429 pure N-vinylacetamide (60% recovery) was obtained.

N-vinylacetamide (15 g), water (459), xylene (909) and SPAN60 surfactant ( 4 g) was polymerized in analogy to the method described in Example 1. The N-vinylacetamide homopolymer was precipitated by adding acetone. This polymer has a concentration of 1.5XlO as determined by gel permeation chromatography.
It had a molecular weight of '.

Example 4 N-vinylacetamide homopolymer of Example 3 (10
9) was dissolved in water and mixed with concentrated hydrochloric acid (2 molar equivalents). The resulting mixture was heated to reflux for 48 hours (approximately 1
10'C! ). Concentrated hydrochloric acid was added to the reaction mixture until the polymer precipitated. The acid solution was decanted. The precipitated polymer was redissolved in water and reprecipitated using methanol to yield 8.8 g of product having a viscosity of 324 cps as a 1% aqueous solution.

Examples 5-9 N-vinylformamide (NVF) was polymerized in the same manner as described in Example 1. Data regarding the polymerization recipe and the resulting emulsion are shown in Tables 1 and 2 below, respectively.

1st Table 5 15 30 Octane 55 2.5 0
．． 05 -6 15 30 Octane 5
5 2.5 0.05 0.25 Pinol 125
7 15 10 Octane 75 2.5 0
．． 05 -8 15 30 Hexane 9
0 2.5 0.05 -9 15 3
0 Hexane 90 2.5 0.05 0.
25 Poly(vinylamine) Table 2! 4111 Emulsion viscosity (cps) Homopolymer molecular weight 5 4 7
xlO@6 4
7XlO'7 4
6xlO'8 4 6
×1069 4 6X
106 Example 10 In this example, the reverse phase emulsion polymerization of N-vinylformamide according to Example 1 was attempted using toluene, xylene and kerosene separately as the hydrocarbon liquid phase. Although high molecular weight N-vinylformamide polymers were obtained in both cases, the emulsions were unstable and broke.

Example 11 This example demonstrates the need for an azo type initiator. Repeating the procedure of Example 1 using sodium persulfate or ammonium as the initiator failed, as no polymer was obtained. This failure is thought to be due to a redox reaction that may have occurred between the monomer and the persulfate.

Example 12 In this example, poly(N-vinylformamide) was prepared according to the solution polymerization procedure of Example 12 of U.S. Pat. No. 4,421,602. The isolated polymer is
1.4× by aqueous gas phase chromatography (GPC)
It was determined to have a molecular weight of 106.

Example 13 A poly(N-vinylformamide) emulsion was prepared according to the procedure of Example 69 of U.S. Pat. No. 4,500,437. The resulting polymer emulsion was pasty and unstable.

Isolated poly(N-vinylformamide) is aqueous GP
It had a molecular weight of 5.1 x 106 as measured at C.

Example 14 N-vinylformamide was polymerized according to the procedure of Example 20 of U.S. Pat. No. 4,500,437.

The product was a viscous liquid with a molecular weight less than 5X106.

Example 15 The effectiveness of poly(vinylamine), poly(vinylamine hydrochloride) and poly(N-vinylacetamide) of the present invention when used in a flocculant for kaolinite clay was tested and
Comparisons were made to commercially available polymers, specifically polyacrylamide, polyacrylic acid and guar gum.

0.01% polymer solution (12,5+++Q) was added to 25
was added to an equal volume of raw kaolinite clay slurry (200 m (5.5 g in 2% Kc12 aqueous solution) in a stoppered graduated cylinder of mff. The cylinder was inverted 5 times. The concentration of clay was 3.6. Measurements were taken at 9.15.30.45 and 60 minutes later.The results are shown in Figure 1.

It has been found that high molecular weight poly(vinylamine) has excellent aggregation ability. In view of the sedimentation rate and compactness of the aggregates, it may be of interest for water treatment.

Example 16 This example demonstrates the application of poly(vinylamine) according to the present invention to tertiary oil extraction. Two vinylamine homopolymers and two commercially available polymers, specifically xanthan and hydrolyzed polyacrylamide, were evaluated at 1500 ppm in artificial seawater using a low shear Brookfield viscosity of 7.9 sec-'. did.

Table 3 Vinylamine (7MM) 1500
16 13 vinylamine (0,6MM)
1500 62 Xanthan XC (2M
M) 1500 50 4
Hydrolyzed polyacrylamide (2MM) 1500
15 3a seawater-3%NaCl2+0
．． 3% CaCQ2; pH=6b Model LVF, 7
．． 9 sec" Table 3 shows that vinylamine homopolymer with a molecular weight of about 7XlO' outperforms commercially available polymers as well as lower molecular weight poly(vinylamine). Vinylamine homopolymer showed improved viscosity stability at high temperatures compared to other polymers.

Example 17 In this example, very high molecular weight vinylamine (V
Am ) homopolymers and low molecular weight versions were compared to guar for use as fracture acidifying compositions.

The polymer concentration was 0.5% and the viscosity was FANN35.
It was measured at 5LOsec-' using a viscometer, R, B, and sensor.

Table 4 10 10 22 26 3 12.5 j15
6 6.511 2 9 Vinylamine homopolymers with a molecular weight of 27 million have higher viscosity behavior than homopolymers with lower molecular weights and also perform better at high temperatures than their commercial counterparts, namely guar. Ta.

Example 18 This example demonstrates that the drilling mud containing the vinylamine homopolymer of the present invention functions with enhanced performance.

A typical drilling mud formulation is prepared as follows.

Clay dispersion A: Aquagel Gold Seal bentonite clay 11.19 Potassium chloride 8g water
Hydrate 400g clay;
Disperse day and night.

Polymer solution B: Polymer 29 was dissolved in 400 g of water, mixed for 2 to 4 hours,
Then, the pH was adjusted to 6.

Dispersion A (200g) to polymer solution B (2009)
and mixed for 4 hours. Rheology measurements were performed using a FANN-35 viscometer at 300 and 600 rpm using standard API procedures.

Table 5 VAm (80M) 3.7 2.5 0 2.5
VAm (0,61 Jl) 6.0
4.5 0 3.0
VAm (7MM) 14.0 11.0 3/4
6.0 xanthan (2MM) 8.8 5.5
3/4 6.5 Table 5 shows that very high molecular weight vinylamine homopolymers have the best behavior at room temperature.

Example 19 A high molecular weight vinylamine homopolymer exhibited surprisingly high viscosity in saturated brine solution. This property is important in completion fluids used in oil wells.

Polymer 19 was mixed with 100 g of a saturated salt solution, and the viscosity was measured to prepare a saturated salt solution.

Table 6 VAm (0,6MM) 3 1100
VA (71i1M) 11.5 30
0 Example 20 This example demonstrates the use of vinylamine homopolymer as a dry strength agent in paper making.

A size of paper chromatography grade material was soaked in water, passed through a squeeze roll while being measured, and weighed. The amount of water absorption was calculated and determined to be constant between sheets. The required polymer weight per unit volume of water (dry/dry) was determined to give a polymer absorption of 0.5% to the sheet weight.

A low molecular weight f[(80M) vinylamine homopolymer and polyvinyl alcohol were used at 0.75%. 3
A high molecular weight (IJM) vinylamine homopolymer with a very high viscosity of 200 cps is 0.188
% solids and its impregnation level was estimated to be 0.125% compared to the others. The pH of the polymer was adjusted to 4.5 before sheet saturation.

Table 7 blank 11.5 0.6 71
VAm (80M) 13.5 2.5 7
7VAm (7MM)” 14-5 3.1
89VINOL 107 PVOHb (60M) 1
2.5 2.0 80a Impregnated amount of 0.125% with respect to other 0.5% b Polyvinyl alcohol manufactured by Air Products and Chemicals Very high molecular weight vinyl amine homopolymer becomes low molecular weight vinyl amine homopolymer In comparison, 1/4 of the amount was found to be an effective dry strength enhancer in papermaking.

Example 21 This example demonstrates the retention of vinylamine homopolymer in paper making.

Immediately prior to manufacturing the handsheets, softwood and one piece of bleached kraft pulp were each suspended at a 1.5% consistency in deionized water. The pulp was then mixed in a weight ratio of 1:1 and used in equal amounts of 30 g (open dry basis) for each set of handsheets. Addition of 10% anatase TiO2 based on fiber weight followed by stirring for 5 minutes. (
T10□ was predispersed at 10% solids in deionized water). Enough pulp to form a 2.5 g handsheet was removed and treated with the polymer, followed by gentle stirring for 30 seconds. The treated fiber suspension was then added to nople and wood sheet molds containing sufficient deionized water to give a consistency of 0.04%. A handmade sheet formed from a fiber suspension is passed between blotting paper materials at 50 ps.
ig for 5 minutes and then drum dried for 7 hours at 200°F in contact with one side of the blotting paper.

According to this procedure, 0.0.01゜0
．． The polymer was added to the fiber suspension at a consistency of 0.5% at loadings of 0.05.0.1.0.2 and 1%. Maintain pH at 5. A handmade sheet made by the method described was adjusted to 50% RH and 73°F, and TAPPI
Filler retention capacity was tested using standard methods.

Table 8 Polymer TiO2 retention (%
) VAm (7MM)
93.1VAm (80M)
It was found that poly(vinylamine) with a molecular weight of 83.3 PAM-Polyacrylamide 7 MM exhibits excellent TiO2 retention ability when added in an amount of 0.1 to 0.2 relative to the wood bulb.

The present invention provides very high molecular weight poly(N-vinylamides) and derivatized poly(vinylamines) with applications in the fields of water treatment, tertiary oil extraction and paper production by inverse emulsion polymerization.

[Brief explanation of the drawing]

The accompanying drawings illustrate the high molecular weight poly(vinylamine) and poly(N-
Figure 2 is a graphical representation of the effects of vinyl acetamide (vinyl acetamide) and other prior art polymers. Patent applicant: 2 people other than Air Products & Chemicals, Inc.

Claims (1)

[Claims] 1) have an average molecular weight of at least 10^6, and 5
consisting essentially of a 5-28% aqueous hydrochloric acid solution containing 0.2-2% by weight of poly(vinylamine) of which 0% or more is hydrolyzed, and at 300 rpm) 510 sec^-^1 and R_1B_
Acidified fracturing fluid with a FANN35 viscosity of 10-100 cps per sensor. 2) The poly(vinylamine) is 1.8 to 9×10^6
The acidified fracturing fluid of claim 1 having an average molecular weight of . 3) The acidified fracturing fluid of claim 1, wherein the poly(vinylamine) is about 90% or more hydrolyzed. 4) The acidified fracturing fluid of claim 1 which also contains 0.5-1% crosslinking agent based on the weight of the poly(vinylamine). 5) The acidified fracturing fluid of claim 1 containing 0.5% by weight of poly(vinylamine) having an average molecular weight of 7x10^6. 6) an aqueous hydrochloric acid solution and a thickener containing as thickener 0.2 to 2% by weight of poly(vinylamine) having an average molecular weight of at least 10^6 and about 90% or more hydrolyzed; An acidified fracturing fluid consisting of: 7) The acidified fracturing fluid of claim 6, wherein the poly(vinylamine) has an average molecular weight of 1.8 to 9 x 10^6. 8) The acidified fracturing fluid of claim 7 which also contains 0.5-1% crosslinking agent based on the weight of the poly(vinylamine). 9) The acidified fracturing fluid of claim 8 containing about 0.5% by weight poly(vinylamine) having an average molecular weight of 7x10^6. 10) The fluid of claim 7, wherein the poly(vinylamine) is about 99+% hydrolyzed.