HU187343B - Hydroxy-aluminium-type compositions without solide materials for deep drilling - Google Patents

Abstract

FIELD OF THE INVENTION The present invention relates to solids-free liquid compositions suitable for deep drilling which comprise hydroxyaluminum aluminum polycations of from 1.5 to 5.5, preferably 2.5 to 4.0, of aluminum salt and alkaline hydrolysing alkali metal compound, and optionally, up to 500 parts by weight of Al3 + ions contain known water soluble electrolyte. Compositions of the present invention are characterized in that, in addition to the components listed above, one or more water-soluble nonionic polysaccharides in the amount of from 1 to 15 parts by weight of Al3 + ions are preferably starch, dextran, hydroxyethylcellulose and / or carboxymethylhydroxyethylcellulose and the like. in any case, up to 10 parts by weight of Al3 + ions contain one or more water-soluble hydrophilic groups or anionic vinyl, acrylic, dicarboxylic and / or cellulose polymers or copolymers. Theological features, filtration characteristics, and rock stabilizing effects of compositions of the above composition are in all respects the requirements of modem technologies. -1-

Description

The present invention relates to hydroxyaluminium-based, non-solids compositions having improved properties, which may be used primarily for deep drilling purposes.

Drilling fluids used in hydrocarbon exploration are subject to increasing and often conflicting requirements. In addition to traditional functions, such as drill removal, hole balance, sludge formation, drill cooling and lubrication, drilling fluids must allow for increased drilling speeds, stability of the hole wall, and especially at high temperature operations. - have adequate heat resistance. However, the protection of productive (hydrocarbon storage) layers and the preservation of the original storage conditions must be given increasing importance.

The rinse aid components (filtrates, solids, etc.) entering the storage layers during drilling impair the original permeability of the storage rock. This deleterious effect can be particularly severe when the storage layer contains a water-sensitive material which may swell, disperse, and thereby block flow channels and pores as a result of a rinse aid filter.

In order to prevent damage to the storage layers, a chemical medium must be provided in drilling fluids (eg flushing, hole finishing, fracturing) that allows the materials to be stabilized. Electrolytes are widely used for this purpose. One of the simplest and cheapest known solutions is the use of sodium chloride. Experience has shown that potassium salts, including potassium chloride, can be used with better results than their corresponding sodium salts, since K ⁺ ions are specifically adsorbed in clay minerals and have a very high inhibitory effect on the swelling or dispersion of clay minerals (Mondshine, TC 197 22)

Very good results can also be obtained with electrolytes containing trivalent and tetravalent cations (such as aluminum, chromium, zirconium, etc.) (Velcy, C.D., Journal of Petroleum Technology, September 11, 1969, pp. 1111-1118).

Subsequent experience has shown that the stabilizing effect of aluminum compounds can be greatly enhanced by the addition of an appropriate amount of an alkali metal hydroxide, preferably sodium hydroxide, to the aluminum salt solution to form ring-shaped hydroxyaluminum polycations (Reed, MG: 1972, J.G. 860-864). Of the known drilling fluids, systems containing hydroxyaluminum polycations provide the most favorable results in terms of material stabilization. A disadvantage, however, is that the drilling fluids containing hydroxyaluminum polycations do not meet the theological and filtration characteristics as they do not contain an anti-filtration agent and have virtually the same viscosity as water.

Drilling fluids containing hydroxyaluminum polycations can improve their theological and filtration properties by mixing water-insoluble solid components with the fluids, but this necessarily entails a reduction in drilling speed and drilling performance. Thus, in order to improve theological and filtration properties, materials which are perfectly soluble in the drilling fluid used, but which do not degrade or even enhance the stabilizing effect of hydroxyaluminium polycations, should be employed.

In our experiments, it has been found that the addition of a defined amount of water-insoluble non-ionic polysaccharide to solids-free drilling fluids containing hydroxyaluminum polycations and water-soluble electrolytes known per se, but not water-soluble, can significantly improve We can adjust the water holding capacity of the system according to the requirements. It has also been found that adding a certain amount of auxiliary polymer to the drilling fluid, namely one or more water-soluble, hydrophilic or anionic vinyl, acrylic, dicarboxylic and / or cellulose polymers or copolymers, can significantly increase and, at the same time, the auxiliary polymers have a positive influence on theological properties and water retention.

Accordingly, the present invention relates to solid-free liquid compositions for deep-drilling purposes comprising hydroxyaluminum polycations of from 1.5 to 5.5, preferably from 2.5 to 4.0, in the form of an aluminum salt and an alkaline hydrolyzing alkali metal compound, optionally Containing up to 500 parts by weight of known water-soluble electrolyte, based on the weight of Al ³⁺ ions. The compositions of the invention are characterized in that, in addition to the components listed above, one to more than one part by weight of Al ³⁺ ions of one or more water-soluble non-ionic polysaccharides, preferably starch, dextran, hydroxyethylcellulose and / or carboxymethylhydroxyethylcellulose and optionally containing up to 10 parts by weight, based on the weight of Al ³⁺ ions, of one or more water-soluble polymers or copolymers containing hydrophilic groups or anionic vinyl, acrylic, dicarboxylic and / or cellulose.

As used herein and in the specification, the term "solids-free" means that the drilling fluid does not contain any insoluble solids when diluted to the Al ³⁺ ion concentration (typically 0.5-10 kg / m ³ ) commonly used in deep drilling operations. For ease of storage and transport, drilling fluids may also be marketed in the form of concentrates which are diluted with water to the desired final concentration immediately before use. Although these concentrates may occasionally contain undissolved solids, these concentrates also include these concentrates because, when diluted before use,

187 3α3 any solid components that may be present will be dissolved completely.

The compositions of the invention may conveniently contain starch, dextran, hydroxyethylcellulose and / or carboxymethylhydroxyethylcellulose as water-soluble non-ionic polysaccharides. Of the non-ionic polysaccharides, starch and hydroxyethylcellulose have been particularly preferred. The compositions may conveniently contain from 2.5 to 10 parts by weight of the nonionic polysaccharide (s), based on the weight of Al ³⁺ ions.

In addition to the non-ionic polysaccharides, the compositions containing no auxiliary polymer may contain ca. At temperatures up to 400 K, they can be used very well for deep drilling. However, in the case where the compositions are to be used in operations at elevated temperatures, auxiliary polymer (s) are added to the drilling fluid to increase heat resistance. The additional benefit of using auxiliary polymers, in addition to a significant increase in heat resistance, is that theological properties of the system and water retention are further improved.

As mentioned above, water-soluble, hydrophilic or anionic polymers or copolymers of vinyl, acrylic, dicarboxylic and / or cellulose, such as, for example, sodium polyacrylate, sodium polymethacrylate, pyrrolidone, partially hydrolyzed polyacrylamide, acrylamide / maleic anhydride copolymers, sulfonated polystyrene, sulfonated styrene / maleic anhydride copolymers, carboxymethyl cellulose. The compositions of the invention may contain up to 10 parts by weight of Al ³⁺ ions, preferably 0.5 to 5 parts by weight of auxiliary polymer.

If desired, electrolytes known in the art such as sodium chloride, potassium chloride, calcium chloride and the like are known to enhance the anti-dispersion effect of the compositions. we can give. If necessary, the density of the compositions may be increased by the incorporation of weighting agents (e.g., barite, limestone, etc.) in the oil industry.

By using the compositions of the invention, the drilling speed can be increased. The compositions, like well-known drilling fluids containing hydroxyaluminum polycation and optionally electrolyte, stabilize the puncture wall and maintain the productivity of the clay-contaminated storage layers. The compositions have the particular advantage that they have good theological properties and water retention properties, and that compositions containing the auxiliary polymer have a high heat resistance. These compositions retain their advantageous properties even after heat treatment at 423-473 K.

The composition, preparation and application characteristics of the compositions of the invention are described in detail in the following examples without limiting the scope of the invention.

Example 1

Dissolve 30 g of aluminum sulphate octadecahydrate (Al ₂ (SO ₄ ) ₃ · 18 H ₂ O) in 400 ml of water and add 12.5 g of sodium hydroxide in 100 ml of water while stirring. Further, 5 g of polyvinyl alcohol and 15 g of starch are dissolved in the resulting solution with vigorous stirring.

The application characteristics of the resulting liquid (before and after heat treatment) are summarized in Table 1.

f. spreadsheet

, .... Plastic Temperature,. . "Viscosity, mPa s flow border, Pa Water discharge, cm ³ pH 298 28 14.3 12.5 11 423 21 10.7 12.0 8

Example 2

Dissolve 30 g of aluminum chloride hexahydrate (AlCl 3 · 6H ₂ O) in 400 ml of water and add 15 g of sodium hydroxide in 100 ml of water with stirring. Then 7.5 g of starch and 7.5 g of polyvinyl alcohol are dissolved in the solution.

Measured before and after heat treatment For the technical characteristics of the fluids in Table 2. stone ³⁰ zöljük.

Table 2

u-_ · ι. Plastic Homersesdet,. . j, viscosity, mPa - s flow border, Pa Water discharge, cm ³ PH 298 25 10.2 20 8 423 21 8.2 15 5.5

Example 3

10 g of starch, 5 g of polyvinyl alcohol and 4.5 g of sodium hydroxide are dissolved in 400 ml of water, and 10 g of aluminum sulphate octadecahydrate dissolved in 100 ml of water are added with vigorous stirring.

The application characteristics of the resulting liquid measured before and after heat treatment are shown in Table 3.

Table 3

Temperature,

K

Plastic viscosity, mPa · s

Flow limit,

Pa

Water Drop,

P ^H

55 298 21 9.2 8.0 11 423 14 4.1 17.0 8.5

Example 4

Dissolve 10 g of starch, 0.5 g of sodium polyacrylate and 4.5 g of sodium hydroxide in 400 ml of water and stir in 100 ml of water with stirring.

10 g of aluminum sulfate octadecahydrate are added.

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The application characteristics of the resulting liquid measured before and after heat treatment are shown in Table 4.

Table 4

Temperature. BOW »mPa s flow border, Pa Water Drop, cm ' PH 298 19 6.1 12 11 453 17 9.7 14 10

Example 5

Dissolve 10 g of aluminum sulfate octadecahydrate in 500 ml of water and add 4.5 g of sodium hydroxide. Then, 1 g of partially hydrolyzed polyacrylamide and 10 g of starch were mixed into the solution.

The application characteristics of the resulting liquid, measured before and after heat treatment, are shown in Table 5.

Table 5

u- ii.i. Plastic Temperature, mPa · s flow border, Pa Water Drop, cm ' pH 298. 13 4.4 15 10.5 423 9 3.7 18 10

Example 6

10 g of starch, 5 g of carboxymethylcellulose and 4.5 g of sodium hydroxide are dissolved in 400 ml of water and 10 g of aluminum sulphate octadecahydrate dissolved in 100 ml of water are added. The application characteristics of the resulting liquid at 298 K are shown in Table 6.

Table 6

Plastic viscosity, mPa -s flow border, Pa water-loss, cm ' PH 27 ' 13.7 17 11

Example 7

Dissolve 10 g of aluminum sulphate octadecahydrate in 400 ml of water and dissolve in 100 ml of water.

4.5 g of sodium hydroxide are added, followed by the dissolution of 5 g of polyvinyl alcohol. As a polysaccharide to the resulting mixture

a) iOg starch,

(b) 10 gdex perry,

(c) 5 g of carboxymethylhydroxyethylcellulose; or

d) 5 g of hydroxyethyl cellulose are added. The specific application characteristics of the thus prepared solution samples at 298 ° C are shown in Table 7.

Table 7

Pattern sign Plastic viscosity, mPa - s flow border, Pa water-loss, cm ' PH the) 21 9.2 8 11 b) 13 7.2 13 10 c) 45 22.7 16 11 d) 27 12.7 17 11

Example 8

Dissolve 10 g of starch, 1 g of sodium polyacrylate and 4.5 g of sodium hydroxide in 400 ml of water. To the solution was added 10 g of aluminum sulfate octadecahydrate dissolved in 100 ml of water followed by 25 g of potassium chloride.

The application characteristics of the resulting liquid before and after heat treatment are shown in Table 8.

Table 8 .... . Plastic Temperature, mPa - s flow border, Pa water-loss, cm ' pH 298 17 11.7 11.0 11 453 14 7.1 12.0 10

Example 9

12.5 g of starch, 5 g of polyvinyl alcohol and 12.5 g of sodium hydroxide are dissolved in 400 ml of water and 30 g of aluminum sulphate octadecahydrate dissolved in 100 ml of water are added. The resulting density is adjusted to 1190 kg / m ³ by addition of 150 g of sodium chloride.

The application characteristics of the liquid before and after heat treatment are listed in Table 9.

Table 9

Temperature, K Plastic viscosity, mPas flow border, Pa Water Drop, cm ' PH 298 21 13.3 12 11 ⁴²³ 17 8.7 12 6.5

Example 10

Dissolve 0.75 g of sodium polyacrylate, 10 g of starch and 4.5 g of sodium hydroxide in 400 ml of water and add 10 g of aluminum sulphate octadecahydrate in 100 ml of water. Subsequently, the liquid was brought to a density of 1520 kg / m ^{3 by} addition of 300 g of barite.

The application characteristics of the resulting liquid before and after heat treatment are listed in Table 10.

187,343

Table 10 λ il. Plastic Temperature, mPa s flow border, Pa V flushing, cm ³ pH 298 62 24.0 7 10 423 20 7.5 8 9

Example 11

As described in the previous examples, drilling fluids are prepared from the following components:

(a) Sample:

kg / m ¹ starch

1.5 kg / m ³ sodium polyacrylate dissolved in kg / m ³ aluminum sulphate octadecahydrate and kg / m ³ sodium hydroxide dissolved in tap water

(b) sample:

kg / m ¹ starch

1.5 kg / m ^{3 of} sodium polyacrylate kg / m ^{1 of} aluminum sulphate octadecahydrate and kg / m ^{1 of} sodium hydroxide dissolved in kg / m ^{1 of} potassium chloride in tap water

(c) sample:

kg / m ¹ starch

1.5 kg / m ^{3 of} sodium polyacrylate kg / m ^{3 of} aluminum sulphate octadecahydrate and kg / m ^{3 of} sodium hydroxide dissolved in kg / m ^{3 of} sodium chloride tap water

(d) sample: 20 kg / m ³ starch 10 kg / m ³ PVA 20 kg / m ³ aluminum sulphate oktadekahid- 5 kg / m ³ and formed from sodium hydroxide hydroxyaluminum sulfate dissolved in tap water (e) sample: 20 kg / m ³ starch 10 kg / m ³ PVA 20 kg / m ³ aluminum sulphate oktadekahid- 5 kg / m ³ and formed from sodium hydroxide 25 kg / m ³ hidroxialumínium sulfate NaCI

dissolved in tap water

A dispersion test was conducted to evaluate the effectiveness of the above-mentioned drilling fluids in terms of hole wall stability. During the tests, the sample liquid 2 · 10 - mixed "" 4 10 "'m with water-sensitive kőzetszemcsékkel and utoklávban kőzetszemcséket rotating 433 ° K to disperse the liquid ²⁵ dékinintákban 5 hours. Fluids having the smallest dispersion of the particles are most advantageous in terms of perforation.

The observed results are all. in Table. All. Table 4 shows that all drilling fluids meet the requirements and, in particular, compositions containing the electrolyte additive have an excellent stabilizing effect.

The exemplified drilling folyadékkompo ³⁵ zíciók properties meet the requirements of the most modern technology requirements, and the values of the parameters - can be varied within wide limits - according to actual needs.

Table 11

Features (a) sample (b) sample (c) sample (d) sample (e) sample Tap water Density, kg / m ³ 1050 1050 1190 1050 1190 1000 Particle size distribution,% particle size 10 ⁴ (m): 20 56.0 75.5 91.3 55.1 94.3 3.1 12.5 12.1 9.3 2.0 11.8 2.5 3.7 2.5 11.3 6.0 1.3 10.0 1.8 62.6 0.56 1.6 1.3 1.9 1.6 0.9 24.0 > 0.56 19.0 7.9 3.5 21.5 0.5 6.6

Finally, we conducted comparative experimental parameters (Table 12) and also that our product is two that clearly demonstrates its inventive heat resistance far beyond the extremely good properties of the known materials in our drilling fluid (Table 13).

Claims (3)

A solids-free composition, preferably for deep drilling purposes, containing up to 500 parts by weight of known water-soluble electrolyte, based on the weight of Al ⁴ ions of aluminum salt and alkaline hydrolyzing alkali metal compound, optionally , between 5, OH / A1 molar ratio between aluminum hydroxy-polycation preferably from 2.5 to 4.0 in an amount of 1-15 parts by weight of one or more water soluble non-ionic polysaccharide, preferably starch, dextran, hydroxyethyl cellulose, and Al ions ³⁴ weight / or carboxymethylhydroxyethylcellulose and optionally up to 10 parts by weight based on the weight of Al ³⁴ ions, of one or more water-soluble hydrophilic or anionic vinyl, acrylic, dicarboxylic and / or cellulose polymers or contains copolymer. Composition according to claim 1, characterized in that the nonionic polysaccharide comprises starch and / or hydroxyethyl cellulose. Composition according to claim 1 or 2, characterized in that it comprises sodium polyacrylate, polyvinyl alcohol, partially hydrolyzed polyacrylamide, acrylamide / maleic anhydride copolymer, sulfonated styrene / maleic anhydride copolymer and / or carboxymethyl cell as auxiliary polymer.