RU2520190C1 - Isolation method of water influxes to well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: isolation method of water influxes to a well includes determination of the well intake under the maximum pressure, injection of a gel-forming compound to the formation with further addition of a compound non-filterable to the formation. The above compounds are pumped down at simultaneous pressure control at the well head. The process holding of the well is made under pressure. Excess of the compound non-filterable to the formation is flushed from the annular space by counter-pressure back-flushing. The gel-forming compound is used with the following ratio of ingredients, wt %: xanthane biopolymer 0.4-0.6, triethanolamine titanate-1 0.5-0.8, water - the remaining part in volume of V_gf calculated as per the specified mathematic expression. Injection is made with the permanent flow rate under pressure at least equal to 0.7 of the formation intake. The gel-forming compound is used with addition of precipitated chalk stone as the compound non-filterable to the formation with the following ratio of ingredients, wt %: xanthane biopolymer 0.4-0.6, triethanolamine titanate-1 0.5-0.8, precipitated chalk stone 5-10, water - the remaining part.

EFFECT: improvement of processability and efficiency in isolation of water influxes to the well due to creation of a stronger water shutoff screen.

1 ex, 3 tbl

Description

The invention relates to the oil and gas industry, can be used to isolate water inflows into the well.

Analysis of the current level of technology showed the following:

- a method of isolating water inflows into a well is known, which consists in injecting a resin-based polymer composition into the processed interval of the well. For the geological and technical characteristics of a particular well, the optimal percentage ratio of the components of each portion of the water-soluble polymer composition containing epoxyphenylene resin, hardener, water is determined. Prepare the first portion of the water-soluble polymer composition with a viscosity of 29.575-512.881 mPa · s and the second portion of the water-soluble polymer composition with a viscosity of 512.881-878.37 MPa · s. The first portion of the water-soluble polymer composition is sequentially introduced into the treated interval of the well, then the second portion, the portions of the water-soluble polymer composition are sold with the process fluid, then the composition is polymerized and the well is washed (see RF patent No. 2462585 dated 02.14.2011, class E21B 33 / 138, C09K 8/42, publ. 09/27/2012).

The disadvantage of this method is the lack of manufacturability and efficiency of isolation of water inflows into the well, a short waterless period of operation of the well, the possibility of an emergency. This is due to the following reasons. As a result of the interaction of the ingredients of the water-soluble polymer composition, the cured epoxyphenylene resin has a globular-type microheterogeneous structure, and the formation of the structure is already observed in the liquid phase at the initial stages of curing. The size of the globular particles (of the order of 10 ³ A) depends both on the ingredient composition and on the curing conditions (the particle size decreases with increasing temperature). As the size of the globules decreases, the electric strength of the polymer increases, and its density decreases. Due to the presence of water in the water-soluble polymer composition that does not contain reactive groups, the epoxyphenylene resin and hardener do not participate in the formation of a network, but accumulate at the boundaries of globular formations, which leads to a sharp decrease in the strength of this composition, therefore, it will not provide the necessary durable waterproofing screen. In addition, when crosslinking an aqueous solution of epoxyphenylene resin, a syneresis will be observed, which also reduces the strength of the resulting insulating screen.

When using a water-soluble polymer composition with the stated viscosity and above, an emergency may occur due to the curing of the composition used in tubing tubing. Resins are very sensitive to changes in concentrations (hardener / resin) that are difficult to maintain in the well. The use of a hardening polymer composition can lead to failure of cementing units or a pumping unit, there is a possibility of complications associated with loss of tubing mobility in the well, which, in turn, does not allow for the processability of this method of isolating water inflows into the well. According to the text of the description of the invention, the polymerization time of the used polymer composition is from two to six hours. A longer polymerization time (6 hours) can lead to dilution of the composition with produced water and blurring of the insulating screen, which reduces the efficiency of the work being done.

In addition, the use of this method in the field will lead to unproductive costs and the cost of ongoing work to isolate water inflows into the well. The use of a ring knife to remove the remnants of the composition requires additional tripping;

- as a prototype, a method of isolating water inflows into a well was taken, including the injection of a grouting composition into the formation with the washing out of its excess from the column space by backwash with backpressure. Gel-forming compositions that are filtered into the formation are subsequently pumped into the formation, followed by fixing with a hardening composition that is filtered or unfiltered into the formation — synthetic resin or cement mortar, and the back pressure when removing excess grouting composition when it is absorbed by the formation is set from 0.6 to 0.9 of the final selling pressure cement composition into the formation, and when not absorbed by the formation - from 0.9 to 1.0 of the final pressure to push the cement composition into the formation, while the pressure on the curing time of the tampon important composition in the isolation zone set from 0.1 to 0.5 of the final pressure of selling cement slurry into the reservoir (see RF patent No. 2273723 from 06/07/2004 according to CL E21B 33/13, publ. 10.04.2006) .

The disadvantage of this method is the lack of manufacturability and efficiency of isolation of water inflows into the well, a short waterless period of operation of the well, the possibility of an emergency. This is due to the following reasons. During the sequential injection of compositions of different structure - filtered and then consolidated by hardening, a mixing zone will necessarily form, as a result of which breakthrough channels for produced water can form in the near-well zone of the well. In addition, premature thickening of the mixing zone of these compounds in the well is possible, which will impair the ability to force them into the formation. For these reasons, it is impossible to form a high-quality high-strength screen in an isolated interval, which accordingly reduces both manufacturability and the effectiveness of this method of isolating water inflows into a well.

The lack of exposure to the time of the water-insulating gel-forming composition before washing the well can lead to the washing out of a significant part of it from the pore space of the bottom-hole zone of the productive formation and to dilution with squeezing liquid, which will not provide the necessary efficiency of the work to isolate water inflows into the well.

The washing out of excess cement composition from the column space by backwashing is carried out when it is absorbed by the formation with a back pressure equal to 0.6-0.9 of the final pressure of the grouting composition into the formation. Absorption may occur in heavily drained areas, resulting in the need for repeated insulation work, which, in turn, will increase the material and technical costs and time of the insulation work.

In view of this, this method cannot be used with high manufacturability and efficiency to isolate water inflows into the well.

The technical result that can be obtained by implementing the present invention is to increase the manufacturability and efficiency of isolation of water inflows into the well by creating a more durable waterproofing screen by using compositions with high insulating ability, resistance of the biopolymer base to microbiological destruction; necessary properties that exclude an emergency situation, as well as in increasing the anhydrous period of operation of the well, which leads to additional production of hydrocarbons, expanding the range of biocides.

The technical result is achieved using the known method of isolating water inflows into the well, including determining the injectivity of the well at maximum pressure, injecting a gel-forming composition into the formation, followed by attaching the non-filtering composition into the formation, selling these compositions with simultaneous monitoring of pressure at the wellhead, technological shutter speed of the well under pressure, washing out the excess of non-filtering composition into the formation from the column space by backwash with back pressure. In which the composition is used as a gelling agent in the following ratio of ingredients, wt.%:

Xanthan Biopolymer 0.4-0.6 Triethanolamine titanate-1 0.5-0.8 Water rest,

in the volume of V _th , calculated by the formula

$$V_{g\mathrm{about}}=0.785\cdot \left[\left(D^2-d{}_n{}^2\right)-\left(D_{\mathrm{one}}^2-d{}_{\mathrm{at}}{}^2\right)\right]\cdot h\cdot m\cdot K\cdot K_{\mathrm{one}},$$

where V is the volume of the gelling composition, m ³ ;

D is the diameter of the insulation zone by the gel-forming composition, m;

d _n - the outer diameter of the production casing, m;

D ₁ - the diameter of the insulation zone unfiltered in the reservoir composition, m;

d _in - the inner diameter of the production casing, m;

h is the thickness of the isolated interval, m;

m is the average relative porosity of the reservoir of the isolated interval;

K is the fill factor of the pore space of the isolated interval (0.40-0.45);

K ₁ - coefficient characterizing the degree of drainage of the flooded bottomhole formation zone, (1.05-1.40),

injection is carried out at a constant flow rate at a pressure of P _Zak not less than 0.7 injectivity pressure of the formation R _reception , and as a composition that does not filter out into the formation, a gel-forming composition is used, into which a filler is added - chemically precipitated chalk, in the following ratio of ingredients, wt.%:

Xanthan Biopolymer 0.4-0.6 Triethanolamine titanate - TEAT-1 0.5-0.8 Chemically precipitated chalk 5-10 Water rest,

in the amount necessary to fill the pore space of the bottomhole formation zone to the depth of the perforation holes, after which the well is subjected to technological exposure under pressure for at least 2/3 of the gelation time of the injected compositions, then the excess of the unfiltered composition from the column space is washed backwash while the backpressure is set equal to 0.2-0.5 of the final pressure squeeze unfiltered into the reservoir composition.

The inventive method of isolating water inflows into the well corresponds to the condition of "novelty."

Xanthan biopolymer is available under various trademarks, for example, MS Bioxan, Rio San, Seanec TU, and have the same physicochemical and technological properties, TEAT-1 according to TU 6-09-11-2119-93, chemically precipitated chalk according to GOST 8253-79.

The combined use of xanthan gum and TEAT-1 in the biopolymer compositions in the claimed intervals leads to the formation of a gel - a system with a set of properties that increase the manufacturability and efficiency of isolation of water inflows into the well.

The structure of the resulting gel is as follows

In the process of polycondensation of a xanthan biopolymer with TEAT-1, a spatial mesh frame is formed, the cells of which are filled with immobilized water, which leads to high strength characteristics of the gel. High strength characteristics make it possible to achieve complete blockage of the pores of the insulated formation; the efficiency of isolation of water inflows into the well is increased.

The polycondensation reaction of the xanthan gum biopolymer and TEAT-1 proceeds slowly, since the hydrolysis of triethanolamine titanate proceeds simultaneously. In this case, mixed hydroxo-aqua complexes are formed, which then react with various hydrophilic groups of the biopolymer. The gelation process does not occur instantly, but at a low speed, depending on the concentration of the biopolymer and the concentration of TEAT-1. This leads to the fact that the gelation process proceeds in the entire volume of the compositions used, while the syneresis of the obtained gel is excluded.

As biopolymers of the xanthan gum in the proposed composition, MC Bioxan, Rio San, Seanec TU are used. It is known that any organic substance is easily oxidized in the presence of gaseous oxygen. The presence of the enzyme accelerates the decomposition process. Xanthan biopolymers are water-soluble high molecular weight polysaccharides produced by the microbiological action of various bacteria. That is, it is an extracellular microbial polysaccharide that forms as a coating on each bacterium. Microbial polysaccharides (biopolymers) as an organic material in their physicochemical structure are prone to microbiological destruction - the destruction of the intramolecular bonds of the macromolecules of organic polymers under the influence of moisture, light, oxygen, biological factor or the combined action of these factors, resulting in the release of volatile products ( СО ₂ ), which leads to a change in the physicochemical characteristics of the biopolymer and a decrease in rheological parameters. The loss of technological and structural-rheological properties of biopolymer-based compositions occurs as a result of the latter's low resistance to microbiological degradation, which, in turn, necessitates the use of biocides. The main structural element of the microbial polysaccharide is a bacterial cell. The contents of the body of a bacterial cell, or its cytoplasm, is a jelly-like viscous solution in which various organic and inorganic compounds are dissolved, surrounded by a thin cytoplasmic membrane forming a protoplast. Its main component is complex substances consisting of proteins and fats (lipoproteins). Active transport of nutrients from the environment to the cell through the cytoplasmic membrane is carried out using special enzymes - permeases, which are part of the membrane. The membrane also contains enzymes involved in respiration, in the metabolism of carbohydrates, in the formation of the membrane itself and other important cell functions. The bacterial protoplast is surrounded by a cell wall, ensuring the constancy of the shape of the bacterium. The main component of the wall is a complex compound, the molecules of which are connected to each other using protein bridges and form a polymer structure. The first barrier to the interaction of the biopolymer with biocides is the cell wall and the cytoplasmic membrane. TEAT-1 is involved in the formation of not only chemical bonds, but also has a preserving effect on the biodegradation process, resulting in increased resistance of the biopolymer base to microbiological destruction, which also increases the effectiveness of the proposed method. Due to the complexity of the structure and the multifunctionality of the membrane apparatus of microorganisms, specific mechanisms for the interaction of these substances with bacterial cells of biopolymers are not well understood. Presumably, TEAT-1 molecules interfere with the permeability of the cytoplasmic membrane of the microbial cells of the xanthan biopolymer, inhibiting membrane-bound enzymes. This is due to the ability to interact with the functional groups of TEAT-1 with polysaccharides (amino acids) of the cytoplasmic membrane, which leads to the formation of insoluble complex compounds at the nitrogen atom and the carboxyl group of TEAT-1 with polysaccharides of the cell wall of microbial cells, thereby violating the permeability of the cytoplasmic membrane. The weakening of the integrity of the cell wall leads to the penetration of water from the environment into the cell, cell swelling, and then to rupture of the cytoplasmic membrane and leakage of the contents - the cytoplasm, which is a jelly-like viscous solution, into the external environment, i.e. lysis of the bacterial cell occurs. The destabilization of even one enzyme involved in an important metabolic process stops the entire process of cell activity, thereby increasing the stability of the biopolymer base of the proposed gel-forming composition on a biopolymer basis to microbiological destruction. The use of TEAT-1 reagent as a biocide expands the assortment of the latter. High-quality performance of works on isolation of water inflows into a well depends on an accurate calculation of the volume of injected formulations. The volume of the gel-forming composition is calculated according to the proposed formula, which takes into account the pore and geometric characteristics of the isolation zone as much as possible. In the formula for determining the volume of the used gelling composition, coefficients are introduced that take into account the degree of drainage of the flooded zone of the bottomhole formation zone and the filling of the pore space of the isolated interval. Based on field experience and experimental studies, the fill factor of the pore space of the isolated interval and the coefficient characterizing the degree of drainage of the flooded bottomhole zone of the formation are taken to be 0.40 and 1.05, respectively, with injectivity of the formation of less than 200 thousand m ³ / day, and 0.45 and 1.40 - with an injectivity of more than 450 thousand m ³ / day. The injection is carried out at a constant flow rate at an injection pressure of at least 0.7 formation injectivity pressure. The result is a uniform filling of the annular space with an insulating composition.

The content of xanthan series biopolymer in the compositions used is less than 0.4 wt.%, TEAT-1 less than 0.5 wt.% Is impractical, since it does not provide gel formation.

The content of xanthan series biopolymer in the compositions used is more than 0.6 wt.%, TEAT-1 more than 0.8 wt.% Is impractical, since it leads to accelerated crosslinking, as a result of which complications may arise during the use of the composition.

The content of chemically precipitated less than 5 wt.% In the unfiltered chalk composition does not provide the necessary clogging effect, and more than 10 wt.% Is inappropriate, since there is no improvement in the composition's properties and complications may arise during its use.

Subsequent fixation with a non-filterable composition in the formation is carried out by a gel-forming composition, into which an additional filler is added — chemically precipitated chalk, which acts as a co-filler in the perforation zone. Carrying out this operation ensures the attachment of the bottom-hole zone, prevents the previously pumped gel-forming composition from escaping from the pore space, which eliminates the downhole flow. The composition is pumped in the amount necessary to fill the pore space of the bottomhole formation zone to the depth of the perforations. In the presented formulation of a non-filterable composition with a filler, the optimal quantitative content of the ingredients was selected and in general also contributes to the achievement of the claimed technical result.

The joint use of the above compositions in the method ensures the creation of a high-strength impermeable insulating screen, which improves the efficiency of the proposed method.

After punching the specified compositions carry out technological exposure of the well under pressure for at least 2/3 of the gelation time of the injected compositions. Technological exposure of the well in time is carried out before washing out the surplus of the unfiltered composition into the formation from the column space, which eliminates the removal of the unfiltered composition from the formation when washing the well. Due to the occurrence of the gelation reaction, reliable fixation of the composition is ensured, as a result of which a strong gel-like structure of the insulating screen is formed in a given volume of the isolated interval of the well. It was experimentally established that this time should be at least 2/3 of the gelation time.

The surplus of the unfiltered composition into the formation from the column space is washed out by backwash, while the back pressure is set equal to 0.2-0.5 of the final pressure of the unfiltered composition into the formation. The creation of back pressure at the wellhead from 0.2 to 0.5 of the final pressure to push the composition that does not filter into the formation during the period after the technological exposure of the well under pressure, as indicated above in time, prevents it from being washed out of the bottom-hole formation zone and ensures the formation of a high-strength insulating screen with increased insulating ability. A back pressure value of less than 0.2 of the final selling pressure will not ensure the washing out of its excess, and more than 0.5 may not be practical, as it can lead to a breakthrough of the insulating screen.

The proposed set of operations of the proposed method using the above compositions, accurate determination of the volume provides an increase in manufacturability and efficiency of isolation of water inflows into the well, as well as an increase in the anhydrous period of operation of the well, which leads to additional production of hydrocarbons.

Thus, according to the above, the achievement of the technical result.

Not identified by available sources of fame, technical solutions having features that match the distinctive features of the invention according to the claimed technical result.

The inventive method meets the condition of "inventive step".

In more detail, the essence of the claimed invention is described by the following example.

It is necessary to isolate water inflows into the well. There is no packer behind the tubing.

Example 1

Initial data

The outer diameter of the production casing, d _n , m 0.168 The inner diameter of the production casing, d _in , m 0.154 The outer diameter of the tubing, d _tubing , m 0,073 HKT inner diameter, d _vnct , m 0,062 Reservoir pressure, MPa 5.5 Artificial Slaughter, m 1260 Current slaughter, m 1226 Perforation interval, m 1189-1225 Gas-water contact level, m 1218 The thickness of the isolated interval, h, m 1225-1218 The diameter of the insulation zone gel-forming composition, D, m 1,5 The diameter of the insulation zone with a non-filtering composition D ₁ m (with a depth of perforations of 0.4 m) 0.968 The average relative porosity of the reservoir interval, m 0.26 Pore fill factor spaces of an isolated interval, K 0.42 The coefficient characterizing the degree of drainage flooded zone of the bottomhole formation zone, K ₁ 1,2

1. Determine the injectivity of the well at a maximum pressure of 8 MPa by injecting gas condensate into the reservoir. The injectivity of the reservoir is 400 thousand m ³ / day.

2. Calculate the volume of the gelling composition according to the formula

$$V_{g\mathrm{about}}=0.785\cdot \left[\left(D^2-d{}_n{}^2\right)-\left(D_{\mathrm{one}}^2-d{}_{\mathrm{at}}{}^2\right)\right]\cdot h\cdot m\cdot K\cdot K_{\mathrm{one}},$$

V ₁ = 0.785 · [(1.5 ² -0.168 ² ) - (0.968 ² -0.154 ² )] · 7 · 0.26 · 0.42 · 1.2 = 0.94 m ³ .

Prepare 0.94 m ³ gelling composition in the following ratio of ingredients, wt.%:

Rio San Biopolymer 0.6 TEAT-1 0.8 Water 98.6

919.3 liters (97.8 wt.%) Of water are poured into a container with a volume of 1.5 m ³ , 5.64 kg (0.6 wt.%) Of Rio San biopolymer are added, thoroughly mixed until completely dissolved, circulating with a CA pumping unit -320. In a separate container TEAT-1 in an amount of 7.5 kg (0.8 wt.%) Is dissolved in 7.5 l (0.8 wt.%) Of water, heated to a temperature of 40 ° C. Both solutions are combined and thoroughly mixed.

Calculate the volume of unfiltered into the reservoir composition according to the formula

$$V_2=0.785\cdot \left[\left(D_{\mathrm{one}}^2-d{}_{\mathrm{at}}{}^2\right)\right]\cdot h\cdot m\cdot K\cdot K_{\mathrm{one}},$$

V ₂ = 0.785 · (0.968 ² -0.154 ² ) · 7.0 · 0.26 · 0.42 · 1.2≈0.7 m ³ .

Prepare 0.7 m ³ unfiltered in the reservoir composition. To do this, use a gel-forming composition, in which an additional filler is introduced - chemically precipitated chalk (see Tables 1 and 2), in the following ratio of ingredients, wt.%:

Xanthan Biopolymer 0.5 TEAT-1 0.6 Chemically precipitated chalk 10 Water 88.9

0.62 m ³ (88.3 wt.%) Of water is poured into a 1 m ³ container, 4.2 kg (0.6 wt.%) Of Rio San biopolymer are added, mix thoroughly until completely dissolved, circulating with the CA- pumping unit 320. In a separate container TEAT-1 in an amount of 4.2 kg (0.6 wt.%) Is dissolved in 4.2 l (0.6 wt.%) Of water, heated to a temperature of 40 ° C. Both solutions are combined, 70 kg of chemically precipitated chalk (10 wt%) is added and mixed thoroughly.

3. The gel-forming composition is injected through the tubing in the calculated volume with a constant flow rate at a pressure of P _zak = 5.6 MPa, which corresponds to a value of 0.7 of the maximum pressure of the formation injectivity.

4. Fasten by injection through the tubing of the non-filtering composition into the formation.

5. Sell the above compositions with simultaneous control at the wellhead.

6. Carry out technological exposure of the well under pressure for 80 minutes (2/3 of gelation time).

7. Wash the excess of non-filtering composition into the formation from the column space by backwashing with technical water in a volume of 1.0 cycle with a back pressure at the mouth equal to 2.8 MPa, which corresponds to a value of 0.5 of the final push pressure of the composition that does not filter into the formation.

8. Raise the tubing-73 mm to the surface with control measurement and topping up the wellbore.

9. Lower the tubing string NKT-114 mm.

10. Dismantle the processing equipment, mount the fountain fittings, and pressurize it.

11. Produce gas-dynamic studies of the well.

Thus, the method of isolating water inflows into the well meets the condition of "novelty, inventive step and industrial applicability", therefore, meets the condition of patentability ".

Test report

Table 1 No. p / p Ingredient composition, wt.% Technological properties of the composition Xanthan Biopolymer TEA T-1 Water Gelation time, τ _g , min The strength of the gel, P, MPa Resistance to formation water after 7 days S,% Insulation coefficient, K,% MS Bioxan Rio san Seanec TU one 2 3 four 5 6 7 8 9 10 one 0.4 - - 0.5 99.1 120 0.005 98.0 95.3 2 0.6 - - 0.8 98.6 90 0.008 99.0 99.8 3 0.5 - - 0.75 98.75 one hundred 0.006 98.3 98.5 four 0.3 - - 0.4 99.3 no gelation occurs 5 0.7 - - 0.9 98.4 25 0.008 99.0 99.8 6 - 0.4 - 0.5 99.1 150 0.017 98.5 98.9 7 - 0.6 - 0.8 98.6 120 0,057 99.3 one hundred 8 - 0.5 - 0.75 98.75 135 0,036 99.0 99.1 9 - 0.3 - 0.4 99.3 no gelation occurs 10 - 0.7 - 0.9 98.4 thirty 0,057 99.3 one hundred eleven - - 0.4 0.5 99.1 110 0.015 97.8 96.1 12 - - 0.6 0.8 98.6 80 0,042 98.9 one hundred 13 - - 0.5 0.75 98.75 one hundred 0,027 98.1 98.7 fourteen - - 0.3 0.4 99.3 no gelation occurs fifteen - - 0.7 0.9 98.4 twenty 0,042 98.9 one hundred

table 2 No. p / p Ingredient composition, wt.% Technological properties of the composition Xanthan Biopolymer TEAT -1 a piece of chalk Water Gelation time, τ _g , min The strength of the gel, P, MPa Permeability to water, microns ² Clogging effect, K,% MS Bio xan Rio san Seanec TU before processing after processing one 2 3 four 5 6 7 8 9 10 eleven 12 one 0.4 - - 0.5 10 89.1 120 0.01 3.9 0.183 95.3 2 0.6 - - 0.8 5 93.6 90 0.013 3.4 0.010 99.7 3 0.5 - - 0.75 7.5 91.25 one hundred 0.011 4.2 0,063 98.5 four 0.3 - - 0.4 eleven 88.3 no gelation occurs 5 0.7 - - 0.9 four 94.4 25 0.013 4.1 0.016 99.6 6 - 0.4 - 0.5 10 89.1 150 0,022 4.0 0,044 98.9 7 - 0.6 - 0.8 5 93.6 120 0,063 3.9 0 one hundred 8 - 0.5 - 0.75 7.5 91.25 135 0,041 3.8 0,034 99.1 9 - 0.3 - 0.4 eleven 88.3 no gelation occurs 10 - 0.7 - 0.9 four 94.4 thirty 0,062 4.1 0 one hundred eleven - - 0.4 0.5 10 89.1 110 0,020 4.6 0.18 96.1 12 - - 0.6 0.8 5 93.6 80 0,047 5.3 0,047 99.1 13 - - 0.5 0.75 7.5 91.25 one hundred 0,032 4.7 0.13 97.2 fourteen - - 0.3 0.4 eleven 88.3 no gelation occurs fifteen - - 0.7 0.9 four 94.4 twenty 0,047 4.6 0.44 one hundred

Table 3 p / p Name of culture Number K.O.E. in 1 ml (g) of substrate MS Bioxan Rio san Seanec TU 0.6% aqueous solution with the addition of 0.5% TEAT-1 0.6% aqueous solution with the addition of 0.5% TEAT-1 0.6% aqueous solution with the addition of 0.5% TEAT-1 one Enterobacteriaceae 33 · 10 ⁶ 8 · 10 ³ 3710 ⁶ 9 · 10 ³ 42 · 10 ⁶ 11 · 10 ³ 2 Cytophaga 7210 ⁶ 14 · 10 ³ 5310 ⁶ 12 · 10 ³ 6710 ⁶ 13 · 10 ³ 3 Bacillus mycoides 87 · 10 ⁶ 16 · 10 ³ 4610 ⁶ 7 · 10 ³ 7210 ⁶ 15 · 10 ³

Note:

1. The gelation time is determined by the moment the composition loses its flow properties (stitched into an inseparable solid mass).

2. The plastic strength is determined by a conical plastometer according to the method of P. A. Rebinder, advanced MS Vinarsky (see the Reference Guide to cementing materials / B.C. Danyushevsky, P.M. Aliev, I.F. Tolstykh. - M .: Nedra, 1987. - 373 p.).

3. To determine the resistance to formation water, use the gravimetric method. For this, a previously weighed portion of the gel is placed in a vessel with produced chloride-calcium type water (according to V.N.Sulin) with a total salinity of 73.8 g / l. After 7 days, the sample is weighed and the stability S is determined by the difference in mass according to the formula:

S = (m ₁ -m ₂ ) / m ₁ · 100,

where m ₁ is the mass of the gel sample before interacting with formation water;

m ₂ is the mass of the gel sample after interaction with formation water.

4. The water-insulating ability - the clogging effect is determined by comparing the water permeability indices through a model water-saturated sand core before it is saturated with the studied composition and after saturation. The linear model of the formation is filled with quartz sand, the diameter of the fraction was 0.05-0.36 mm. The initial permeability of the reservoir model was 3.8-5.3 μm ² . Next, the model is saturated with formation water, the mineralization of which was 73.8 g / l, after which the composition that does not filter into the formation is pumped. Studies are carried out at 20 ° C, keeping the samples at a given temperature for 12 hours. For the evaluation criterion of the proposed method, a clogging effect or degree of isolation is taken, which is determined on the basis of the data obtained during the tests, calculated by the formula.

The insulation coefficient is determined by the formula

K = (K ₁ -K ₂ ) / K ₁ · 100,

where K ₁ is the permeability of the reservoir model to the injection of the proposed composition, μm ² ;

K ₂ - the permeability of the reservoir model after injection of the proposed composition, μm ² .

5. The biocidal effect of TEAT-1 on the microbiological destruction of the gel-forming composition is determined by studying the microflora of 0.6% biopolymer solutions of MS Bioxan, Rio San, Seanec TU with the addition of a minimum amount of a crosslinking agent in an amount of 0.5 wt.%.

The biocidal effect of TEAT-1 on solutions of biopolymers is evaluated by identifying and determining the number of microorganisms by seeding serial dilutions of samples on solid nutrient media according to GOST 26670-91. Colony counting is carried out after four weeks of cultivation at room temperature. The number of microorganisms in 1.0 g (cm ³ ) of product M is calculated by the formula

$$M=\frac{N}{m}\cdot C,$$

where N is the degree of dilution of the sample;

m is the amount of inoculum added to the Petri dish, cm ³ ;

C is the rounded arithmetic mean of the number of colonies.

The quantitative and qualitative composition of the isolated microorganisms in 0.6% aqueous solutions of biopolymers is presented in Table 3.

Claims (1)

A method of isolating water inflows into a well, including determining the injectivity of the well at maximum pressure, injecting a gelling composition into the formation, followed by attaching a composition that does not filter out into the formation, selling said compositions with simultaneous monitoring of pressure at the wellhead, technological exposure of the well to pressure, washing out excess composition that does not filter out into the formation from the column space backwash with backpressure, characterized in that as a gelling agent use the composition in the wake the ratio of ingredients, wt.%:
Xanthan Biopolymer 0.4-0.6 Triethanolamine titanate-1 0.5-0.8 Water rest,
in the volume of V _th , calculated by the formula:
$$V_{g\mathrm{about}}=0.785\cdot \left[\left(D^2-d{}_n{}^2\right)-\left(D_{\mathrm{one}}^2-d{}_{\mathrm{at}}{}^2\right)\right]\cdot h\cdot m\cdot K\cdot K_{\mathrm{one}},$$

where V is the volume of the gelling composition, m ³ ;
D is the diameter of the insulation zone by the gel-forming composition, m;
d _n - the outer diameter of the production casing, m;
D ₁ - the diameter of the insulation zone unfiltered in the reservoir composition, m;
d _in - the inner diameter of the production casing, m;
h is the thickness of the isolated interval, m;
m is the average relative porosity of the reservoir of the isolated interval;
K is the fill factor of the pore space of the isolated interval (0.40-0.45);
K ₁ - coefficient characterizing the degree of drainage of the flooded zone of the bottomhole formation zone, (1.05-1.40),
download lead at a constant rate during the injection pressure P is not less than 0.7 _Coll reservoir injectivity pressure P _intake, and as a non-filtering layer are used in the composition of the gelling composition, which additionally administered filler - precipitated chalk, with the following ratio of ingredients, wt%. :
Xanthan Biopolymer 0.4-0.6 Triethanolamine titanate-1 0.5-0.8 Chemically precipitated chalk 5-10 Water rest,
in the amount necessary to fill the pore space of the bottomhole formation zone to the depth of the perforation holes, after which the well is subjected to technological exposure under pressure for at least 2/3 of the gelation time of the injected compositions, then the excess of the unfiltered composition from the column space is washed backwash while the backpressure is set equal to 0.2-0.5 of the final pressure squeeze unfiltered into the reservoir composition.