RU2792390C1 - Composition based on a crosslink polymer system for limiting water inflow in production wells and leveling the injectivity profile in injection wells - Google Patents

Abstract

FIELD: oil production.

SUBSTANCE: compositions used in carrying out measures to limit water inflow in production wells and to equalize the conformance control in injectors. The composition contains 3-10 wt.% of a cross linker in the form of potassium dichromate or sodium dichromate, 0.01-10 wt.% of the pour point time regulator, 0.01-5 wt.% of the rheological properties regulator, 0.01-15 wt.% bridging agent and water. At the same time, the rheological properties regulator includes a modified wood processing product based on cellulose ethers, or a product based on modified xanthan gum, or polyacrylamide. A surfactant based on aminoalcohol derivatives with a content of ethoxylated amines of at least 2 vol.% is used as a pour point time regulator. Polypropylene fibers or calcium carbonate are used as bridging agents. Moreover, the composition additionally contains 3-40 wt.% of the polymer in the form of a sulfite-modified phenylpropane polymer with a molecular weight of more than 35,000 amu. In addition, the composition additionally contains 0.01-5 wt.% of the crosslink activator, which is used as etidronic acid or an acid reagent containing citric and oxalic acids in a ratio of 1:1-3, respectively.

EFFECT: increase in penetration due to the possibility of regulating pour point time of the proposed composition in a wide temperature range (up to 300°C) while maintaining the strength and stability of the formed gel, as well as ensuring the versatility of the composition due to the possibility of using it in terrigenous (porous) and carbonate (fractured) formations.

1 cl, 2 tbl

Description

The invention relates to the oil industry, in particular to compositions used in carrying out measures to limit water inflow in production wells and to equalize the injectivity profile in injection wells.

A number of compositions based on polymeric reagents are known to reduce the permeability of formations with the achievement of a water-blocking effect due to clogging of rock pores with the resulting polymer gel (cross-linked polymer system). Such compositions include compositions based on polymeric reagents, in particular polyacrylamides and/or water-soluble derivatives of polymers of plant origin, with the addition of crosslinkers - reagents of an organic nature or salts of polyvalent metals.

A composition is known for isolating water inflow into a well (RF patent No. 2099520) containing hydrolyzed polyacrylamide, formaldehyde, liquid glass, inorganic acid and polyvalent metal salt. The disadvantages of this composition is the presence in the formulation of substances of II-III hazard classes (formaldehyde, inorganic acid). These substances can harm the environment and human health and require enhanced safety measures when using them. In addition, since the composition does not contain a corrosion inhibitor, inorganic acid will cause corrosion of the casing string, downhole equipment. Another disadvantage of the known composition is the uncontrolled flow time (0.5-6 h).

Known gel-forming composition for blocking formations (AS USSR No. 1 680 950), containing liquid sodium glass, water-soluble derivatives of cellulose, sulfonic acid, bichromate or chromate and filler (inert particulate material). The disadvantages of this composition are uncontrolled fluidity loss time (less than 5 hours at a temperature of 25 ^° C), the impossibility of using the composition at temperatures above 25 ^° C, and the presence in the formulation of substances that lead to corrosion of the casing string and downhole equipment. The mandatory presence of an insoluble filler in a known composition limits its use in low-permeability formations.

The closest in technical essence to the proposed invention is the composition (RF patent No. 2634467), used to limit water inflow into wells, isolate various sources of watering in production wells, eliminate behind-the-casing flows, shut off formations and interlayers, to align injection wells injectivity profiles, representing a gel-forming composition containing in wt.%:

Polyacrylamide (PAA) 20-40 Crosslinker: Potassium or sodium bichromate 2.0 - 4.0 Reducing agent: sodium thiosulfate 4.0 - 8.0 Microfiber Reagent rest.

In this case, the specified microfiber reagent consists of the following components, wt.%:

wood flour 20 - 60 stabilizing additive: xanthan gum or xanthan gum or guar gum or a mixture thereof or polyacrylamide 3 - 10 clay powder up to 100%.

The disadvantages of this composition are:

- the complexity of preparation, due to the need for preliminary preparation of a microfibrous reagent, followed by mixing with the rest of the components and suspending in a mixing liquid;

- low penetrating power due to short fluid loss time (less than 6 hours) at temperatures above 25 °C and high content of microfiber reagent;

- destruction of the polymer component at temperatures above 80 ⁰ C, especially rapid destruction at temperatures above 100 ⁰ C.

The technical result of the invention is to increase the penetrating ability due to the possibility of controlling the time of loss of fluidity of the proposed composition in a wide temperature range (up to 300 ⁰ C) while maintaining the strength and stability of the formed gel.

An additional technical result is to ensure the versatility of the composition due to the possibility of using it in terrigenous (porous) and carbonate (fractured) reservoirs.

The specified technical result is achieved by using a composition based on a cross-linked polymer system for limiting water inflow in production wells and leveling the injectivity profile in injection wells, containing a crosslinker in the form of potassium bichromate or sodium bichromate, a flow loss time regulator, a rheological properties regulator, including a modified wood processing product on based on cellulose ethers, or a product based on modified xanthan gum, or polyacrylamide, a bridging agent and water, while the novelty is that the composition contains a surface-active substance (surfactant) based on derivatives of amino alcohols containing ethoxylated amines not less than 2% by volume, polypropylene fibers or calcium carbonate are used as a bridging additive, while the composition additionally contains a polymer - a sulfite-modified polymer of phenylpropane with a molecular weight of more than 35,000 a.m.u., and also additionally contains a crosslinking activator, which is used as etidronic acid or an acidic reagent containing citric and oxalic acids in a ratio of 1:1-3, respectively, in the following ratio, wt. %:

- crosslinker potassium bichromate or sodium bichromate - 3-10

- flow loss time regulator - 0.01-10

- regulator of rheological properties - 0.01-5

- clogging additive - 0.01-15

- polymer - 3-40

- crosslink activator - 0.01-5

- water - the rest.

The achievement of the specified technical result is provided by the following.

The use of a sulfite-modified polymer - phenylpropane with a molecular weight of more than 35,000 amu, due to the structural features of the molecules, in particular, a large number of active groups, as well as the possibility of partial oxidation of the polymer by the proposed crosslink activator (etidronic acid or an acid reagent containing citric and oxalic acid in a ratio of 1:1-3, respectively), provides gels (cross-linked systems) with a large number of cross-links, due to which high hardness, strength and stability of the resulting gels are achieved.

The features described above allow the proposed composition to be used both in terrigenous (porous) and carbonate (fractured) reservoirs.

To control the flow time, the composition contains the specified polymer and the specified crosslink activator. The introduction of the polymer into the composition of the polymer provides an increase in the time of loss of fluidity (slowdown of gelation) when using the proposed composition in a wide temperature range, especially at temperatures above 80 ⁰ C, which is especially important for hot wells, and the introduction of a crosslinking activator into the composition ensures the control of the time of loss of fluidity, especially at lower temperatures.

The formation of the gel from the proposed composition proceeds in 2 stages, while at the first stage, during the interaction of the specified polymer with the specified crosslink activator, the sulfite-modified phenylpropane polymer with a molecular weight of more than 35,000 a.m.u. is partially oxidized, as a result of which part of the transition metal ions VI- the crosslink activator group passes from the highest oxidation state to an intermediate state and can act as crosslinking ions. Also, during partial oxidation of the specified polymer, as mentioned above, part of the active groups are oxidized to carboxyl groups, which can subsequently react with the resulting crosslink activator ions in the intermediate state.

At the second stage of gelation, the interaction between the obtained ions of the crosslinking activator in an intermediate oxidation state with the molecules of the specified polymer, including the resulting carboxyl groups, occurs.

Due to the introduction into the composition of the flow loss time regulator, namely, surfactants based on derivatives of amino alcohols (ethoxylated amines) with a content of ethoxylated amines of at least 2% by volume, at the first stage of crosslinking, the interaction of the specified polymer (sulfite-modified phenylpropane polymer with a molecular weight of 35000 a.m.u.) with a crosslinking activator, which leads to an increase in the time of loss of fluidity (more than 6 hours) and makes it possible to use the composition at high temperatures. Due to the introduction of acids as a crosslinking activator, their interaction with the polymer at the first stage of crosslinking proceeds more intensively, which leads to a decrease in the fluidity loss time.

Thus, it is possible to use the claimed composition, both at high and at low temperatures, by controlling the time of loss of fluidity, and it is also ensured that gels with high hardness and strength are obtained, while maintaining a low viscosity of the initial composition.

The regulation of the flow loss time, including the possibility of obtaining a composition with a flow loss time of more than 48 hours, allows the claimed composition to be used in technologies for leveling the injectivity profile of injection wells, as well as in technologies for redistributing flows in reservoirs (at a distance from injection wells). And the high hardness, strength and stability of the resulting gels, including at temperatures up to 300 ⁰ C, allow the claimed composition to be used in wells with a steam-cyclic mode of operation, as well as in the treatment of steam injection wells with steam-thermal impact on the formation.

For the treatment of highly permeable, including fractured, reservoirs in the formulation of the claimed composition, it is proposed to use a rheological properties regulator (a modified wood processing product based on cellulose ethers, or a product based on modified xanthan gum, or polyacrylamide) and a bridging additive (polypropylene fibers or calcium carbonate) .

As a clogging additive, insoluble mineral particles (calcium carbonate) or insoluble fibrous materials - polypropylene fibers are used. As a result of the joint use of the proposed regulator of rheological properties and the specified bridging additive, a controlled decrease in the penetrating ability of the composition is achieved, which ensures the elimination of absorptions of the composition and the treatment of exclusively the bottomhole zone of highly permeable (carbonate and terrigenous) formations.

To obtain the claimed composition based on a cross-linked polymer system, the following reagents were used:

No. Reagent name GOST, OST, MRTU, TU, MU, etc. for manufacturing Polymer :
sulfite-modified polymer of phenylpropane with a molecular weight of more than 35,000 a.m.u. Inlig m. VI TU 20.14.71-084-38892610-2017 stapler Sodium bichromate GOST 2651-78 Potassium bichromate GOST 2652-78 Pour Time Controller
Surfactants based on derivatives of amino alcohols with a content of ethoxylated amines of at least 2% by volume INRET TU 20.14.42-097-38892610-2018 Crosslink activator VIKACID (an acidic reagent containing citric and oxalic acids in a ratio of 1:1-3, respectively) TU 2431-057-38892610-2014 Etidronic acid TU 2458-002-50643754-2003 Rheological properties regulator CELSTRACT grade B (modified wood processing product based on cellulose ethers) TU 2231-008-38892610-2012 BURIZAN (product based on modified xanthan gum) TU 9189-018-38892610-2012 Praestol 2530 (polyacrylamide) TU 2216-001-40910172-98 Colmatizing additive Bival 3.5 ( calcium carbonate) TU 5716-077-38892610-2016 Incline ( polypropylene fibers) TU 2272-035-38892610-2013 Water

The proposed compositions based on a cross-linked polymer system with different quantitative ratios of components and using different brands of reagents are presented in Table 1.

The following parameters were used as indicators of the properties of the proposed composition: the effective viscosity of the initial composition at a shear rate of 5 s ^-1 , the time of loss of fluidity when exposed to reservoir temperature, the hardness of the resulting gel, the adhesion force of the resulting gel, the efficiency of isolation of the pore space of the rock.

The viscosity of the initial composition and the flow loss time were determined on an OFITE model 1100 viscometer (USA). The pour point time was defined as the time after which the effective viscosity of the composition at a shear rate of 5 s ^-1 .

The hardness, fracture onset strength, and adhesion force of the bulk precipitate were measured using a Brookfield Texture Analyzer CT3 device (USA).

The effectiveness of isolation of the pore space of the rock after injection of the composition into it was determined using a laboratory unit for determining the filtration and blocking characteristics of process fluids and PIK-OFP/EP compositions manufactured by GeoLogika JSC (Russia). Formation water (density ρ=1.18 g/cm ³ , mineralization 273000 mg/dm ³ , total hardness 1200 meq/dm ³ , pH=3) and oil (density 0.83 g/cm ³ , viscosity 5 mPa∙s), and the water and oil permeability was determined before and after injection of the composition. Based on the results obtained, the residual water resistance factor was calculated as the ratio of the water permeability of the model before injection of the composition to the permeability after injection and structuring of the composition in the model. Also on the presented equipment, the penetrating ability of the composition was determined by determining the maximum injection pressure.

Table 2 shows the properties of the composition based on the cross-linked polymer system.

Based on the comparative experiments (Table 2), it can be concluded that the use of the proposed composition, compared with the known one, makes it possible to reduce the permeability of water-saturated pore channels of the formation to a greater extent due to the higher hardness and adhesion of the resulting gel, to expand the range of fluid loss time at formation temperature due to the introduction of a flow loss time regulator and increase the penetrating ability of the resulting composition by reducing the rheological properties.

Table 1

Composition based on a cross-linked polymer system No. of composition (experiment) Polymer
(Inlig m.VI), wt. % Rheological properties regulator, wt. % Colmatizing additive, wt. % Crosslink activator, wt. % Stapler, wt. % Pour time regulator (INRET), wt. % Water, wt. % 1 40 0.01 0.01 5 10 0.01 44.97 2 40 0.01 0.01 5 6.25 0.01 48.72 3 35 0.01 0.01 5 6.25 0.01 53.72 4 25 0.01 0.01 2.5 8 0.01 64.47 5 10 0.01 0.01 1 3 0.01 85.97 6 25 0.01 0.01 0.5 6.25 1 67.23 7 20 0.01 0.01 0.5 5 0.1 74.38 8 20 0.1 0.01 0.1 5 0.01 74.78 9 8 0.5 0.01 0.01 5 0.1 86.38 10 25 1 0.01 0.01 6.25 2 65.73 eleven 15 1 5 0.01 6.25 2 70.74 12 5 3 5 0.01 5 1 80.99 13 5 3 5 0.01 3 3 80.99 14 15 5 15 0.01 3 10 51.99 15 15 5 15 0.01 3 10 51.99 16 15 5 15 0.01 3 10 51.99 Prototype No. of composition (experiment) Polymer reagent, wt. % Stapler, wt. % Reducing agent, wt. % Microfiber Reagent Wood flour wt. % Stabilizing additive, wt. % Clay powder, wt. % 17 0.4 0.04 0.08 2.10 1.78 0.03 0.29 18 0.4 0.10 0.10 2.10 1.78 0.03 0.29 19 1.6 0.16 0.32 3.40 1.00 0.10 2.30 20 1.6 0.16 0.20 1.60 0.50 0.10 1.00 21 1.6 0.16 0.15 1.99 0.19 0.30 1.50 22 1.6 0.16 0.10 1.99 0.19 0.30 1.50 Notes:
1. Compositions 17-22 - Prototype.
2. As a regulator of rheological properties, it is used in compositions 1-3, 6, 8, 10, 12 - CELSTRACT m. B - a modified wood processing product based on cellulose ethers; in compositions 4-5, 7, 13-14 - BURIZAN - a product based on modified xanthan gum; in compositions 9, 11, 15-16 - Praestol 2530 - polyacrylamide ..
3. As a bridging additive, it is used in compositions 1-11, 15-16 - Inclin - polypropylene fibers; in compositions 12-14 - Bival 3.5 - calcium carbonate.
4. As a crosslinking activator, it is used in compositions 1-7 - etidronic acid; in compositions 8-16 - Vikatsid - an acidic reagent containing citric and oxalic acids in a ratio of 1: 1-3, respectively.
5. Used as a crosslinker in compositions 1-4, 6, 10-14, 16 - sodium bichromate; in compositions 5, 7-9, 15 - potassium dichromate.

table 2

No. p / p Initial viscosity, mPa⋅s Time of loss of fluidity when exposed to reservoir temperature, h Gel hardness, g-force Strength of the beginning of destruction, g-force Gel adhesion force, g-force Reservoir fluid permeability coefficient Terrigenous rock carbonate rock <100 mD ˃100 mD <100 mD ˃100 mD Composition injection pressure, MPa Residual resistance factor for the water phase, d.u. Composition injection pressure, MPa Residual resistance factor for the water phase, d.u. Composition injection pressure, MPa Residual resistance factor for the water phase, d.u. Composition injection pressure, MPa Residual resistance factor for the water phase, d.u. Temperature 20 ^o C 1 5.4 6 2876 2017 27 3.29 ˃1000 2.38 ˃1000 3.41 ˃1000 1.87 ˃1000 2 5.2 12 1243 963 18 0.75 403 0.53 526 1.2 246.1 0.79 318 3 5.1 8 941 845 17 0.64 378 0.47 306 0.95 60.5 0.65 115 4 5.2 14 892 803 17 0.72 350 0.38 234 0.92 41.15 0.63 38.2 5 4.0 74 512 479 7 0.5 33 0.1 14 0.74 24.15 0.48 27.3 6 256 8 213 167 10 6.7 12 4.3 eleven 5.4 11.1 3.8 9.8 Temperature 60 ^o C 7 5.0 16 1149 947 15 0.67 364 0.53 526 0.93 ˃1000 0.77 ˃1000 8 4.7 17 976 893 15 0.63 355 0.47 306 0.67 680 0.42 304.5 9 4.8 12 947 901 16 0.65 358 0.38 234 0.49 468 0.4 232 10 20.3 76 489 358 7 0.55 20.9 0.21 25.7 0.37 30.89 0.38 67 eleven 248 4 312 155 7 7.5 223 3.9 73.1 7.2 136 1.36 62 Temperature 80 ^o C 12 31.4 6 483 391 13 0.69 368 1.23 210 0.53 ˃1000 0.33 ˃1000 13 29.8 18 376 284 eleven 0.62 327 0.95 150 0.45 ˃1000 0.30 754 14 54.1 38 351 277 9 0.54 310 0.92 142 0.36 835 0.21 526 15 52.0 72 316 259 5 0.52 90.2 0.8 52 0.27 142 0.15 59 16 482 2 206 80 2 10.3 202 9.7 81 10.1 99 9.6 47 Temperature 150 ^o C 17 76.9 6 253 203 9 0.27 ˃1000 0.14 ˃1000 0.53 ˃1000 0.33 ˃1000 18 473 1 91 45 1 9.4 44.6 7.8 75 9.3 140 7.2 128 Temperature 200 ^o C 19 77.5 4 214 173 7 only for carbonate reservoir 0.53 ˃1000 0.33 ˃1000 20 614 1 78 2 0.7 9.1 131 8.9 121 Temperature 300 ^o C 21 76.4 4 205 171 6 only for carbonate reservoir 0.53 ˃1000 0.33 ˃1000 22 621 1 65 1 0.2 9.2 112 8.8 97

Claims (2)

Composition based on a cross-linked polymer system for restricting water inflow in production wells and leveling the injectivity profile in injection wells, containing a crosslinker in the form of potassium bichromate or sodium bichromate, a flow loss time regulator, a rheological properties regulator, including a modified wood processing product based on cellulose ethers, or a product based on modified xanthan gum, or polyacrylamide, a clogging agent and water, characterized in that a surfactant based on amino alcohol derivatives with a content of ethoxylated amines of at least 2 vol.% is used as a regulator of the fluid loss time, as clogging additives use polypropylene fibers or calcium carbonate, while the composition additionally contains a polymer - a sulfite-modified polymer of phenylpropane with a molecular weight of more than 35,000 amu, and also additionally contains a crosslink activator, which is used Use etidronic acid or an acidic reagent containing citric and oxalic acids in a ratio of 1:1-3, respectively, in the following ratio, wt.%: crosslinker potassium bichromate or sodium bichromate 3-10 pour point regulator 0.01-10 rheology regulator 0.01-5 clogging additive 0.01-15 polymer 3-40 crosslink activator 0.01-5 water rest