RU2349731C2 - Method of shut-off and restraint of water production in wells - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method can be implemented at shut-off of drill string casing and casing string borehole annulus, at sealing casing strings, at sealing threaded connections and shutting-off watered interlayers in oil and gas wells. According to the method the shut-off and restraint of water production in wells consists in pumping into a well an insulating material containing formaldehyde resin, an initiator of polymerisation and water, also in forcing this material through and in holding it for solidifying and hardening; the insulating material as formaldehyde resin contains urea-formaldehyde or acetone- formaldehyde resin and additionally - oxy-ethylated isononylphenols, oxy-ethylated monoalkylphenols or their mixture, natural or synthetic rubber or their mixture at the following combination of components, wt %: urea-formaldehyde or acetone- formaldehyde resin 20.0-70.0, oxy-ethylated isononylphenols, oxy-ethylated monoalkylphenols or their mixture 0.5-4.0, natural or synthetic rubber or their mixture 0.05-50.0, polymerisation initiator 0.5-3.0, water - the rest.

EFFECT: upgraded quality of water producing zones shut-off in producing and pressure wells under various geological, physical and thermo-baric conditions.

5 cl, 4 tbl, 8 ex

Description

The invention relates to the oil industry, in particular to methods based on polymer compositions that are cured in reservoir conditions to isolate and limit water inflow and can be used to isolate annular and annular spaces, seal casing strings, seal threaded joints and isolate waterlogged layers in oil and gas wells.

Known methods of isolation and limitation of water inflows based on synthetic resins that are cured in reservoir conditions (see Blazhevich V.A., Umrikhina V.A. Grouting materials for RIR in wells, Ufa, 1992, pp. 44-50).

The disadvantages of the known method is the temperature restrictions on their use in connection with the fast unregulated timing of their curing.

A known method of isolation and limitation of water inflow into wells, including the injection into the repaired area of a polyurethane prepolymer, selling it and holding it for the period of curing and curing. (RF patent No. 2231625, IPC 6E21B 33/138, publ. 02.10.2004).

The disadvantage of this method is the lack of efficiency and complexity of carrying out in the field conditions of the technological operation, which affects the effectiveness of the method.

The closest in technical essence to the invention is a method of isolating the formation, which includes injecting into the injection or production well cured in the reservoir conditions of the insulating material containing synthetic resin, hardeners and water, where as a synthetic resin take urea-formaldehyde resin, oxyl - SM, hardener - salt aluminum in the form of crystalline hydrate and water. (RF patent No. 2272892, IPC 7E21B 33/138, publ. 03/27/2006).

The disadvantage of using the proposed method is that when applying this insulation material, the facies and physicochemical features of the host rocks are not taken into account and, as a result, the selectivity of the materials used in the method with respect to water-saturated intervals of facies-heterogeneous formations is not taken into account. Another disadvantage of this method is the lack of effectiveness of the ongoing technological operation, namely the low penetrating ability of high molecular weight polymer composition in the amount of violation, therefore, it is not possible to process the entire necessary interval and to qualitatively block the water-developing zones.

The basis of the proposed invention is the creation of a method of isolation and limitation of water inflows in both producing and injection wells, which allows it to be used in various geological and geophysical, thermobaric conditions and mineralization of formation water.

The problem is solved in such a way that in the method of isolating and restricting water inflows into wells, including injecting into the well an insulating material based on a cured polymer under formation conditions, selling it and holding it for the time of curing and curing, a composition based on synthetic resin is used as an insulating material the following composition, wt.%:

Urea-formaldehyde resin 20.0-70.0 Surfactants and / or mixtures thereof 0.5-4.0 Natural or synthetic rubber and / or 0.05-50.0 their mixture Polymerization initiator 0.5-10.0 Water rest

Or

Acetone-formaldehyde resin 20.0-70.0 Surfactants and / or mixtures thereof 0.5-4.0 Natural or synthetic rubber and / or 0.05-50.0 their mixture Polymerization initiator 0.5-10.0 Water rest

In variants of the method:

- the method according to claim 1, additives are added to the composition;

- the method according to claim 1, the filler is introduced into the composition;

- the method according to claim 1, additives and a filler are added to the composition;

- the method according to claim 1 or 2 or 3 or 4, the composition is pumped cyclically, and the squeezing liquid is pumped after each cycle;

The urea-formaldehyde resin is taken from the KFMH brand, which is a polycondensation product of urea, formaldehyde and diethylene glycol and is produced according to TU 6-06-59-89 in the form of a uniform, viscous liquid.

The acetone-formaldehyde resin is taken from the ACP brand, which is a polycondensation product of acetone with formaldehyde and is produced according to TU 228-006-90685-2002 or GOST 25820-83 in the form of a uniform, viscous liquid.

As surfactants, ethoxylated isononylphenols are used, for example, OP-10 is the product of processing a mixture of mono- and dialkylphenols with ethylene oxide according to GOST 8433-81; neonols AF-9-6,8,9,10,12 - ethoxylated monoalkylphenols based on propylene trimmers are taken according to TU 38.507-63-300-93; sulfonol according to TU 07510508; Neftenol ML according to TU 2481-056-17197705-00 or their mixtures.

As natural or synthetic rubbers or their mixtures, for example, latex is used according to TU 38,303-05-45-94, brand SKS-65GPSBS, SKD-L250 according to TU 3810-3-696-89, rev. 2 dated 01.03.94, SKD-PS according to TU 3810-3-248-84 rev. 5 from 01.07.96, BS-65A according to TU 38.103550-84, BM-5 according to TU 38.40373-01, RSS-1 (Indonesia), SVR 3L (Vietnam), DVHB-Sh according to TU 2294-049-05766764-02, VDVHMK according to TU 2294-049-05766764-02, SKN-40IHM according to TU 38.10354-76, which is an aqueous dispersion of rubbery polymers (pH = 10-11) of a milky color.

As a polymerization initiator for a urea-formaldehyde resin, for example, carboxylic acids and their salts can be used - alkaline stockpile of caprolactam production (SHSPPK) in accordance with TU 113-03-488-84 from ext. No. 1, 2 and / or aluminum-containing waste from the production of benzene alkylation with olefins according to TU 38.302163-89.

As a polymerization initiator for an acetone-formaldehyde resin, for example, carboxylic acids and their salts can be used - alkaline stockpile of caprolactam production (SHSPPK) according to TU 113-03-488-84 from ext. No. 1, 2 and / or sodium hydroxide (liquid caustic) RD according to GOST 2263-796.

The fillers used are, for example, mineral powders according to GOST 52129-2003, atactic propylene according to GOST 23001-88, chalk, clay powder according to TU 5751-002-58156178-2002, Portland cement according to GOST 1581-96, wood flour according to GOST 16361-87 , carbon black according to GOST 7885-86, epoxy according to GOST 10587-93, crumb rubber according to TU 38-105590-84, sulfur according to GOST 127.1-93, etc.

As additives, for example, powdered polyacrylamide (PAA) according to TU 6-16-2532-810, polyacrylamide DP9 81-77, polyethylene oxide, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (OEC), lignosulfonate (TU 61-04-225-79 ), isopropanol (GOST 9805-76), ethyl alcohol and a reagent based on methyl alcohol (SNPCH-IPG-11 according to TU 39-05765670-OP-179-93), bottoms from the production of butyl alcohols according to TU 38.1021167-85.

As the squeezing liquid, for example, anhydrous oil, produced water, technological well fluid, for example, saline water solution, etc. can be used.

We give an example of the preparation of polymer compositions.

Example 1. To 693 grams of urea-formaldehyde resin at room temperature add 214 grams of rubber - SKS-65-GPBS, Neonol AF9-12 - 2 grams, water - 2 grams, ShchSPK - 5 grams, then 84 grams of aluminum hydrochloride are added with stirring with a batcher. Stirred for 30 minutes until a homogeneous mass is formed, after which the composition is left until completely cured. Other compositions are prepared in a similar way, the contents of the components of which are shown in table 1.

Example 6 (from table 2). To 68.3 grams of acetone-formaldehyde resin at room temperature add 22.4 grams of rubber - SKS-65-GPBS, Neonol AF9-12 - 0.3 grams, water - 0.1 grams, then 8.4 grams of SCHSPK are added with stirring with a dispenser and 0.5 grams of caustic. Stirred for 30 minutes until a homogeneous mass is formed, after which the composition is left until completely cured. Other compositions are prepared in a similar way, the contents of the components of which are shown in table 2.

To confirm the effectiveness of the isolation method, the laboratory studies the time of the insulating and structural-mechanical properties of the polymer stone formed as a result of the reaction.

The polymerization time of the composition is determined from the moment all components are mixed until the complete polymerization and loss of fluidity.

The criterion for evaluating the insulating effectiveness of the composition is the residual resistance factor (η), which is determined by the following formula:

η = (K ₀ -K ₁ ) 100 / K ₀ ,

where K ₀ - coefficient of permeability to blockage of the reservoir model, μm ² ;

K ₁ - permeability coefficient after plugging the reservoir model, μm ² .

Studies are carried out on layer-by-layer heterogeneous reservoir models with a cross section of 60 mm and a length of 1000 mm, consisting of highly permeable (800-1200 mD) and low permeability (50-140 mD) zones separated by an impermeable membrane and connected to the same pressure vessel. The required permeability values were achieved by the degree of grinding of the disintegrated core of real deposits.

Structural and mechanical properties of polymerized stone are determined according to GOST 310.4-84 and GOST 26798.2-85.

The adhesive properties of a polymerized stone with a metal surface (σ _m ), rock (σ _p ) and cement stone (σ _k ) are determined by shearing coaxially arranged cylinders with a diameter of 25 and 50 mm and a length of 50 mm, in the annular space of which the composition was polymerized.

The test results are shown in table 3.

The method is as follows. In the isolation interval of the producing or injection wells by means of a pumping unit, the inventive composition is pumped into the formation. The maximum concentration of fillers and additives is determined by the retention capacity of the dispersion medium. Produce the squeezing of the composition into the reservoir with squeezing fluid. The well is left for technological exposure for 12-48 hours.

In an embodiment of the method, the composition is pumped cyclically, and after each cycle, squeezing liquid is pumped.

The processing end time is controlled by any known method.

After technological exposure, the underground equipment is lowered into the well and put into operation.

The treatment of producing and injection wells is carried out both separately and simultaneously. It is possible to re-treat production and injection wells.

To prove the compliance of the claimed invention with the criterion of "industrial applicability", we give specific examples to determine the effectiveness of the isolation method and restrict water inflows into wells.

Example 1. Process an oil well. Technological tubing pipes (tubing) are lowered into the well with packer equipment and a funnel installation opposite the upper holes of the perforation interval. When the annular valve is closed by technological tubing, the calculated volume of reagent No. 1 from table 1 is pumped through the pumping unit from table 1 to 3.5 m ³ . Then push it into the reservoir 3.5 m ^{3 of} mineralized water (density γ = 1.15 g / cm). Close the well and conduct technological exposure for 48 hours. After the reaction time has elapsed, the well is washed to the bottom, the underground equipment is lowered and the well is put into operation. If necessary, carry out reperforation.

Examples 2-8. Perform technological operations as in example 1. Additionally, additives or a filler or additives and a filler are added to the reagent. The volume of the composition, the amount, concentration of additives and fillers is determined based on the specific geological and geophysical conditions of the well being processed: injectivity, temperature, open formation thickness, results of geophysical studies, the degree of depletion of the site’s reserves.

The data in examples 1-8 are summarized in table 4.

Using the proposed method allows to widely regulate the nature of the impact on the reservoir, providing a blocking of water-saturated zones of the reservoir. The formation of polymer stone during the interaction of all components of the composition occurs in the pore space of both terrigenous and carbonate reservoirs. As a result, a high-strength polymer stone is formed that is resistant to aggressive formation media and acid-base solutions.

Table 4 No. Well Category Repair purpose The number of cycles Formulation Success insulation composition squeezing liquid The inventive method one mining elimination of annular circulation one Composition 1 ^(1-5) min water + 2 mining plantar water flow restriction 2 Composition 2 ^(1-4) + PAA (polyacrylamide) pres. water ++ 3 mining sealing e / columns one Composition 3 ^(1-4) + Clay powder oil + four discharge increased coverage four Composition 4 ^(1-4) + CMC + Wood flour pres. water ++ 5 mining elimination of annular circulation one Composition 6 ^(1-4) + Portland cement min water ++ 6 mining selective restriction of water inflow 2 Composition 7 ^(1-5) oil ++ 7 mining sealing e / columns one Composition 8 ^(1-5) + crumb rubber + Portland cement pres. water + 8 discharge increased coverage 6 Composition 9 ^(1-5) + CMC + PAA + DM min water ++ Note: The composition number with the degree designation, the degree is the composition number from tables 1 and 2.

Claims (5)

1. A method of isolating and restricting water inflow into wells, including injecting into the well an insulating material containing formaldehyde resin, a polymerization initiator and water, selling it and holding it for the time of curing and curing, characterized in that the insulating material contains urea-formaldehyde or acetone-formaldehyde resin and additionally ethoxylated isononyl phenols, ethoxylated monoalkyl phenols or a mixture thereof, natural or synthetic rubber, or a mixture thereof in the following ratio of components, wt.%:
urea-formaldehyde or acetone formaldehyde resin 20.0-70.0 ethoxylated isononylphenols, ethoxylated monoalkylphenols or a mixture thereof 0.5-4.0 natural or synthetic rubber or a mixture thereof 0.05-50.0 polymerization initiator 0.5-3.0 water rest 2. The method according to claim 1, characterized in that the material is additionally introduced polyacrylamide, or polyethylene oxide, or carboxymethyl cellulose, or hydroxyethyl cellulose, or ethyl alcohol, or a reagent based on methyl alcohol, or bottoms from the production of butyl alcohol. 3. The method according to claim 1, characterized in that the filler is additionally introduced into said material. 4. The method according to claim 2, characterized in that the filler is additionally introduced into said material. 5. The method according to any one of claims 1 to 4, characterized in that the download and sale of the specified material is carried out cyclically.