RU2715543C1 - Water-swellable elastomeric composition for manufacturing of sealing elements of packer equipment - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to water-swellable elastomeric materials and can be used in production of rubber swellable packing elements of packer equipment used in oil and gas industry. Water-swellable elastomeric composition for making sealing elements of packer equipment based on butadiene-nitrile rubber, comprising a vulcanizing agent – sulfur, mercaptan series vulcanization accelerators – altaks and captax, vulcanization activators – zinc oxide and stearin, dispersant – glycerin, filler – colloidal silicic acid BS-120 and water-swellable reagents – sodium-carboxymethyl cellulose and acrylamide-based polymer, additionally contains filler of technical carbon TU P234, and as polymer based on acrylamide – copolymer of acrylamide with potassium acrylate.

EFFECT: increased degree of swelling of elastomer material in fresh water, in 22 % aqueous solution of sodium salt and aqueous solutions of sodium salt of intermediate mineralization.

1 cl, 2 tbl

Description

The invention relates to water-swellable elastomeric materials and can be used in the manufacture of rubber swellable sealing elements of packer equipment used in the oil and gas industry.

Known water-swelling elastomeric composition based on nitrile butadiene rubber, modified by a combination of an acrylic copolymer with carboxymethyl cellulose (Pat. WO No. 2010039131, IPC A61L15 / 30, A61L15 / 60, C08L1 / 00, C08L 33/00, C08L9 / 02, E21B 33/00, C08L9 / 02, E21B 33/00, C08L9 / 02, E21B published on 04/08/2010).

The disadvantage of such rubbers is that they are characterized by a relatively high swelling efficiency only in aqueous solutions of salts of low mineralization (3.5-6.0%).

Known used in the manufacture of packers water-swelling elastomeric mixture based on nitrile butadiene rubber containing 7.0-10.0 mass. including vulcanizing group, 250.0-451.0 mass. including a copolymer of acrylamide and sodium acrylate with a degree of crosslinking in the range of m = 0.01-0.05%, 35.0 wt. including filler, 15.0-36.0 mass. including mineral fiber and 15.0 mass. including plasticizer (Pat. RU No. 2580564, IPC E21B 33/12, F16J 15/02, publ. 04/10/2016).

The disadvantages of this invention is the low level of elastic strength properties of the elastomeric material after contact with water, as well as the complex technology of its use in the manufacture of the packer.

Known water-swelling rubber mixture for packer equipment based on nitrile butadiene rubber, containing a sulfur vulcanizing agent, Altax vulcanization accelerator, vulcanization activators zinc oxide and stearin, carbon black filler, asbestos fibers and water-swelling reagents crosslinked polyacrylamide POLYSWELL30 and NO.2 carboxylicum. , IPC C08L 9/02, C08L 33/26, C08K 3/04, C08K 3/06, C08K 3/22, C08K 5/47, E21B 33/12, publ. 05/04/2018).

The disadvantage of the rubber mixture is the low degree of swelling of the elastomeric material of the packer in 22% saline.

Closest to the proposed technical solution is a water-swellable elastomeric composition for swellable sealing elements of packer equipment based on butadiene-nitrile rubber, containing a sulfur vulcanizing agent, mercaptan vulcanization accelerators, vulcanization activators zinc oxide and stearin, a filler colloidal silica bis-120 acidifying agent, BS-120 glyceric acid agent and water-swelling reagents sodium carboxymethyl cellulose and a cationic anionic polymer resin based on acrylamide Ultrares DS (Pat. RU No. 2683462, IPC C08L 9/02, C08L 33/26, C08K 3/04, C08K 3/06, E21B 33/12, published March 28, 2019). The composition has a good degree of swelling in fresh water.

The disadvantage of the elastomeric composition is the low degree of swelling of the elastomeric material of the packer in saline solutions of various concentrations.

The task of the invention is the creation of an elastomeric material with increased ability to volumetric swelling in fresh water and aqueous solutions of sodium salt of various mineralization.

The technical result of the invention is to increase the degree of swelling of the elastomeric material in fresh water, in a 22% aqueous solution of sodium salt, and aqueous solutions of sodium salt of intermediate mineralization.

The technical result is achieved due to the fact that the water-swelling elastomeric composition for the manufacture of sealing elements for packer equipment based on nitrile butadiene rubber, including a sulfur vulcanizing agent, mercaptan vulcanization accelerators - altax and captax, vulcanization activators, zinc oxide and stearin, a dispersing agent glycerin, - colloidal silicic acid BS-120 and water-swelling reagents sodium carboxymethyl cellulose and a polymer based on acrylamide, with additional rzhit as filler carbon black TU P234, and the polymer based on acrylamide - acrylate copolymer of acrylamide with potassium in the following ratio, wt. h: BNKS-28 rubber - 100.0; BS-120 - 10.0; TU P234 - 30.0; zinc oxide - 5.0; stearin - 1.0; glycerin - 2.0; sulfur - 2.0; altax - 1.0; captax - 1.0; a copolymer of acrylamide with potassium acrylate - 50.0-100.0; sodium carboxymethyl cellulose - 50.0-100.0.

According to the claimed invention, a polarized butadiene-nitrile rubber of the BNKS-28 AMN grade (TU 38.30313-2006) with an average content of acrylic acid nitrile units of 28% is used as the basis for the water-swelling elastomeric composition.

The vulcanizing group includes: sulfur (GOST 127-76); vulcanization accelerators - altax (dibenzothiazoldisulfide) (TU 6-14-851-86), captax (2-mercaptobenzthiazole) (TU 739-74). The activating system is based on a combination of zinc oxide (GOST 202-84) and stearin (GOST 6484-96). As a dispersing agent, glycerin (GOST 6259-75) is used.

The role of reinforcing filler in the formulation is performed by BS-120 colloidal silicic acid (GOST 18307-78) and carbon black TU P234 (GOST 7885-86).

Sodium carboxymethyl cellulose (TU 2231-001-53535770-01) and a copolymer of acrylamide with potassium acrylate (apparent density 85-90%; pH 8.1; cation exchange capacity 4.6 meq / g; maximum absorption in deionized water) are used as water-swelling reagents. 400 g / g; water retention at pF1 980 ml / l), for example, the AQUASORB 3005 trade arch.

Samples of the finished elastomeric material were exposed in fresh water and aqueous solutions of sodium salt of various salinity at a temperature of 23 ± 2 ° C.

The essence of the invention lies in the fact that the claimed combination of sodium carboxymethyl cellulose with a copolymer of acrylamide with potassium acrylate is used as water-swelling reagents in the formulation of a polar rubber-based rubber composition. The combination of these reagents of natural and synthetic nature in the elastomeric composition provides a high degree of swelling of the elastomeric material in fresh water and aqueous solutions of salts of various salinity (up to 22% inclusive).

When the obtained from the claimed water-swelling elastomeric composition of the elastomeric material in contact with these environments due to the specifics of diffusion processes and polyelectrolyte interactions, a synergistic effect is achieved, consisting in a higher degree of volumetric swelling compared to the prototype.

The formulation of the compositions (examples 1-2) according to the claimed invention and the formulation of the prototype are shown in table 1.

Table 1

Mixture ingredients The content of ingredients, mass. h 1 2 prototype Butadiene-nitrile rubber BNKS-28 100 100 100 BS-120 10 10 40 TU P234 thirty thirty - Zinc oxide 5 5 5 Stearin 1 1 1 Glycerol 2 2 2 Sulfur 2 2 2 Altax 1 1 1 Captax 1 1 1

Acrylamide copolymer with potassium acrylate fifty 100 - Sodium Carboxymethyl Cellulose fifty 100 25 Cationic-anionic acrylamide-based polymer Ultreres DS - - 25

The manufacture of a water-swellable elastomeric composition is carried out using a high-speed mixer of the Brabender type and laboratory rollers according to technology generally accepted in the rubber industry.

Water-swelling elastomeric materials were made by vulcanization of the obtained compositions in a hydraulic press according to the optimal temperature-time regime previously identified using a Monsanto 3000 Professional rheometer. The physicomechanical properties of the standard samples were determined on a Zwick 5.0 kN tensile testing machine in accordance with GOST 270-75. Volumetric swelling of elastomers in fresh water and aqueous solutions of sodium salt of various mineralization was carried out in accordance with GOST 9.030-74 (method A). The physicomechanical properties of the samples after swelling were determined on a Zwick 5.0 kN tensile testing machine in accordance with GOST 9.030-74 (method B).

The obtained values of the elastic strength properties, as well as comparative data on the degree of volumetric swelling with the prototype during the exposure time of 200 hours, are presented in table 2. This exposure time is due to the regulatory requirements for well servicing.

Analysis of the numerical values of table 2 indicates that, compared with the prototype obtained from the claimed water-swelling elastomeric composition, elastomeric materials are characterized by a higher degree of volumetric swelling. Foreign ratios of the minimum and maximum contents of the combination of water-swelling reagents do not provide the desired technical result and are therefore not illustrated by examples. The inventive water-swelling elastomers are capable of large volumetric swelling in aqueous solutions of sodium salt of various mineralization while maintaining an acceptable level of physico-mechanical properties.

table 2

Sample Code
Indicator Examples 1 2 prototype The degree of volumetric swelling in fresh water after exposure to 200 h,% 181 629 206 The degree of volumetric swelling in a 3.5% aqueous solution of sodium salt after exposure to 200 h,% 81 248 81 The degree of volumetric swelling in a 6% aqueous solution of sodium salt after exposure to 200 h,% 69 205 57 The degree of volumetric swelling in a 10% aqueous solution of sodium salt after exposure to 200 h,% 60 185 36 The degree of volumetric swelling in a 22% aqueous solution of sodium salt after an exposure of 200 hours,% fifty 164 23 Conditional tensile strength *, MPa 6.2 / 2.3 3.1 / 2.1 7.5 / 5.1 Elongation at break *,% 214/143 135/126 417/278

Notes: * - in the numerator, the values before contact with fresh water, in the denominator - after exposure in fresh water for 200 hours.

Thus, elastomeric materials obtained from a water-swelling elastomeric composition based on butadiene-nitrile rubber, including a sulfur vulcanizing agent, mercaptan vulcanization accelerators, vulcanization activators zinc oxide and stearin, a dispersing agent glycerin, and technical agent BC-120 BC-4 colloidal silicic acid filler ТС-120 and water-swelling reagents sodium carboxymethyl cellulose and a copolymer of acrylamide with potassium acrylate at the stated proportions, have a high degree of swelling in fresh water and aqueous solutions of sodium salt of various salinity.

Claims (12)

Water-swellable elastomeric composition for the manufacture of sealing elements for packer equipment based on nitrile butadiene rubber, including a sulfurizing agent — sulfur, mercaptan vulcanization accelerators — Altax and Kaptax, vulcanization activators — zinc oxide and stearin, a dispersant — glycerol, and a non-colloidal cream filler 120 and water-swellable reagents - sodium carboxymethyl cellulose and acrylamide-based polymer, characterized in that the composition further comprises as filling carbon black of Tell TU P234, and the polymer based on acrylamide - acrylate copolymer of acrylamide with potassium in the following ratio, mass parts .: Rubber BNKS-28 - 100.0 BS-120 - 10.0 TU P234 - 30.0 Zinc Oxide - 5.0 Stearin - 1.0 Glycerin - 2.0 Sulfur - 2.0 Altax - 1.0 Kaptax - 1.0 A copolymer of acrylamide with potassium acrylate - 50.0-100.0 Sodium carboxymethyl cellulose - 50.0-100.0.