RU2345114C1 - Well killing liquid - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas producing industry, specifically to well killing liquids and can be used in repairs of holes of formation pressure equal or lower that hydrostatic one. Well killing liquid contains, wt %: SEANEC-TU or MC Bioxan - 0.4-1.0; diethylene glycol - 15-25; calcium chloride - 5-10; Morpen - 0.5-1.0; water - the rest.

EFFECT: higher efficiency of well killing due to liquid with improved structure-rheological properties, and hence, with low fluid losses thus proving reservoir retention and reducing well development time with higher frost resistance, higher microbiological destruction stability of biopolymer base, bactericide diversification.

3 tbl, 5 ex

Description

The invention relates to the oil and gas industry, in particular to fluids for killing wells, and can be used for repairs in wells with reservoir pressure equal to or lower than hydrostatic.

Analysis of the current level of technology showed the following:

- well-known fluid for killing a well, the formulation of which has the following ratio of components, wt.%:

Carboxymethyl cellulose (CMC) 58.7-69 Surface-active substance 0.3-0.7 Technical glycerin 30-40 Monoethanolamide 0.3-1.0

(USSR AS No. 796394 dated March 26, 1979, class E21B 43/12, published in Bul. No. 2, 1981).

The disadvantage of this fluid is the lack of efficiency killing wells. This is due to the following reasons: this fluid, due to the high content of CMC polymer in it, has high viscosity values. The latter creates certain difficulties when pumping fluid, which is unacceptable when killing wells, since in the field it leads to technological difficulties when using the specified fluid. Using this fluid does not preserve the natural permeability of the reservoir after release, because CMC has a colding effect on the reservoir. The latter does not contribute to the conservation of reservoir properties of the reservoir, which leads to an increase in the time of well development. During well development, the fluid is extracted with an aqueous surfactant solution, which is filtered into the reservoir and clogs it. Winter use is difficult due to even higher viscosity values.

Known liquid for killing wells, the formulation of which has the following ratio of ingredients, wt.%:

Starch  1.0-2.0 Caustic soda  0.04-0.16 Surfactant  0.05-0.1 Sodium metasilicate  0.2-1.2 Urea Perhydrate  0.07-0.1 Potassium chloride  3.0 Water Rest

(see RF patent No. 2203919 dated December 29, 2000, class C09K 7/02, E21 B 43/12, published in Bull. No. 13, 2003).

The disadvantage of this fluid is the lack of efficiency killing wells. This is due to the following reasons: low values of conditional, plastic viscosity and dynamic shear stress (see Table 1, patent description) give the composition the ability to penetrate deep into the formation and even be absorbed by the formation, and the structural and mechanical properties do not provide the possibility of creating repression on the formation. The surfactant, which is part of the fluid in the specified amount, is not enough for the process of air entrainment (decrease in density), this limits the scope of this fluid in wells with abnormally low reservoir pressures and productive formations of low permeability. Unsatisfactory structural and rheological properties of this fluid and, as a result, relatively high filtration values do not ensure the conservation of reservoir properties of the reservoir. The filtrate penetrates into the reservoir. Well development time is increasing. This jamming liquid also cannot be used in the winter, as it does not have frost-resistant additives;

As a prototype of the selected fluid for killing wells, the formulation of which has the following ratio of components, wt.%:

Xanthan Biopolymer 1,0 Polyalkylene glycol component 2.0 Filtration Reducer 0.3 Clay Swelling Inhibitor 1,0 PH Regulator - KOH 0.05 Water rest

(see RF patent No. 2168531 dated November 9, 1999, class C09K 7/00, published in Bull. No. 16, 2001).

The disadvantage of this fluid is the lack of efficiency of killing wells and the low resistance of the biopolymer base to microbiological destruction. This is due to the following reasons: the liquid is characterized by unsatisfactory structural and rheological properties and, as a result, relatively high filtration values. The joint use of reagents in a liquid does not create a sufficiently coupled system that would reduce filtration. The reagent used to regulate the filtration of PACs and starch together with the biopolymer only form a weak filter cake in the porous reservoir medium, through which a sufficiently large volume of the filtrate easily penetrates, which adversely affects the natural permeability of the reservoir. The interaction of the formation rock with the minimum components of the liquid phase (filtrate) leads to a change in the structure of the formation due to the possible formation of hardly soluble reaction products. A decrease in the capacitance-filtration properties of the reservoir as a result of changes in its structure during development leads to a slight decrease in the recovery coefficient of the formation permeability. The above does not ensure the conservation of reservoir properties of the reservoir and helps to increase the timing of well development. The use of the liquid of the specified formulation in winter is ineffective, since it does not contain frost-resistant additives.

As a result of laboratory studies on the resistance of the polymer base of the liquid to microbiological destruction, the following was revealed: on day 9, the structural and rheological properties of the liquid deteriorate. This is probably explained by the following: if there are three polymers in the liquid (xanthan biopolymer, PAC and CMC), the amount of bactericide in the formulation is not enough to prevent their destruction, the low ability of this bactericide to exert an effect - block certain types of enzymes of cellular microorganisms.

The technical result that can be obtained by implementing the invention is reduced to the following:

- increasing the efficiency of killing wells by using fluids with improved structural and rheological properties and, as a result, with low values of the filtration rate, which ensures the conservation of reservoir properties of the reservoir and helps to reduce the development time of wells while increasing frost resistance;

- increases the stability of the biopolymer base to microbiological destruction;

- the range of bactericides is expanding.

The technical result is achieved using a well-known well killing liquid, consisting of a xanthan biopolymer, a glycol-containing component, a filter reducing agent, a bactericide and water, which contains SEANEC-TU or Bioxan as a xanthan biopolymer, and diethylene glycol as a glycol-containing component. filtration reducer - calcium chloride, and as a bactericide - Morpen in the following ratio of ingredients, wt.%:

SEANEC-TU or MC Bioxan 0.4-1.0 Diethylene glycol 15-25 Calcium chloride 5-10 Morpen 0.5-1.0 Water rest.

The inventive liquid meets the condition of "novelty."

To prepare the kill fluid, xanthan biopolymers of the kind SEANEC-TU or MC Bioxan, diethylene glycol according to GOST 6221-90, calcium chloride according to GOST 450-77, Morpen according to TU 2481-008-22299560-02 are used.

In the process of killing gas, gas condensate and oil wells with a reservoir pressure equal to or lower than hydrostatic, there is an intensive violation of the reservoir properties of the productive formation, a decrease in well productivity. The main requirements for killing fluids include the following:

- maximum conservation of reservoir properties of the reservoir;

- the technological properties of the fluids used must be adjustable over a wide range of mining and geological conditions for operating wells;

- the density of the fluid for killing wells should be sufficient to provide the necessary back pressure on the reservoir;

- ensuring explosion and fire safety.

If used in winter, well killing fluid must be frost-resistant.

Xanthan biopolymers are water-soluble polysaccharides obtained by the microbiological action of bacteria in a hydrocarbonate medium with the addition of protein and inorganic nitrogen. That is, it is an extracellular microbial polysaccharide that forms as a coating on each bacterium. At the final stage, precipitation in isopropyl alcohol is carried out, separation, drying and grinding to a powder state. A feature of the biopolymers used is the presence in their composition of a large number of functional chemically active groups: hydroxyl (OH), carboxyl (COOH), amine (NH ₂ ), carbonyl (C = O), etc. This opens up the possibility of their chemical modification by vaccination, complexation etc. The molecules of these biopolymers include both hydrophilic (functional) and hydrophobic (carbohydrate) groups in their chain, and their hydration proceeds similarly to diphilic molecules only partially, depending on the solvent. Thus, biopolymer molecules are not completely hydrated in water, but only in certain areas. The number of water molecules that make up the hydration shell is usually small, but the volume of hydrated ions compared with unhydrated ions increases sharply. Despite the fact that the volume of hydrated ions increases and it is ten times larger than the volume of unhydrated ions, some volume of unhydrated ions remains. This is due to the uneven packing density of water molecules in the volume of the hydration shell. The high density of the first layers gradually diffusion decreases to the periphery (such layers are called diffuse). The water of hydration shells (layers) is otherwise called bound. During the interaction of the ingredients included in the liquid killing formula, redistribution of water ions (formation of hydration shells) between the functional groups of the ingredients (depending on the size and size of the charges) occurs. This leads to a decrease in the volume of free (unbound) water.

The presence of a large number of active functional groups in the ingredients used together in the formulation of the proposed liquid in the claimed ranges, especially in SEANEC-TU or Bioxan xanthan biopolymers, promotes the formation of a large number of different types of bonds, which leads to the formation of a complex high-molecular compound of a three-dimensional structure. An increase in the volume of bound water in the molecules of the indicated liquid ingredients leads to an improvement in its structural and rheological properties, namely, plastic viscosity, dynamic shear stress, and also static shear stress and, as a result, to low values of the filtration index. As a result, the reservoir properties of the reservoir are preserved, which helps to reduce the time required for well development. However, in their physicochemical structure, microbial polysaccharides (biopolymers) are prone to microbiological degradation - the destruction of macromolecules under the influence of moisture, light, oxygen, a biological factor or the combined action of these factors, resulting in the release of volatile products, a change in the physicochemical characteristics of the biopolymer and a decrease in rheological performance. The loss of technological and structural-rheological properties of biopolymer-based fluids occurs as a result of the latter's low resistance to microbiological degradation, which, in turn, necessitates the use of bactericides.

The main structural element of the microbial polysaccharide is a bacterial cell. The body contents 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 - permease, 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 that ensures the uniformity of the bacterial form. 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 bactericides is the cell wall and the cytoplasmic membrane. The presence of the proposed Morpene liquid, along with diethylene glycol, has an inhibitory effect on the biodegradation process and, as a result, increases the resistance of the biopolymer base to microbiological destruction. Their combined effect as antioxidants (antioxidants) to prevent the destruction process is called - synerism. The use of Morpen as a bactericide in combination with other ingredients allows us to conclude that there is a synergistic effect manifested in improving the properties of the liquid (see test report).

In the chemical literature, 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. Obviously, Morphen molecules carrying negatively charged ions interact with the reactive groups of the peptidoglycone, the main component of the bacterial cell membrane protein (for Morpene, the target groups are protein ketone groups and teichoic acid phosphate groups), thereby disrupting 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 cytoplasmic membrane and leakage of the contents - the cytoplasm, which is a jelly-like viscous solution, into the external environment, i.e., lysis occurs bacterial cells. Therefore, in the proposed composition within 6-15 days there is a maximum increase in viscosity. Diethylene glycol molecules (HOSN ₂ —CH ₂ —O — CH ₂ —CH ₂ OH) penetrate the bacterial cell and interact with various functional groups of enzymes involved in the metabolic processes of the bacterial cell. Inhibition of even one enzyme involved in an important metabolic process suspends the entire process of cell activity, thereby increasing the resistance of the polymer base of the proposed fluid to microbiological destruction. The use of Morpen as a bactericide expands the assortment of the latter. In addition, the liquid has high frost resistance.

The liquid content of SEANEC-TU or MC Bioxan in an amount of less than 0.4 wt.%, Diethylene glycol less than 15 wt.%, Calcium chloride less than 5 wt.%, And Morpen less than 0.5 wt.% Negatively affects the structural and rheological properties , there is a decrease in plastic viscosity, dynamic and static shear stress, increased filtration, reduced resistance of the biopolymer base to microbiological degradation.

The content in the liquid SEANEC-TU or MC Bioxan in an amount of more than 1.0 wt.%, Diethylene glycol more than 25 wt.%, Calcium chloride more than 10 wt.%, And Morpen more than 1.0 wt.% Is impractical since it does not lead to improvement structural and rheological properties and stability of the biopolymer base to microbiological destruction.

Thus, according to the above, the proposed combination of essential features ensures the achievement of the claimed technical result.

According to available sources of fame, technical solutions have not been identified that have features that match the distinctive features of the invention according to the claimed technical result.

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

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

An example of the use of kill fluid in field conditions at a well whose reservoir is represented by Cenomanian deposits.

Initial data

1. Depth of the well, m - 1205

2. Depth of descent of the production casing, m - 1183.5

3. The outer diameter of the production casing, mm - 168

4. The inner diameter of the production casing, D _VEC , mm - 153.4

5. The outer diameter of the tubing, tubing, D _tubing , - 127

6. The inner diameter of the tubing, D _VCT , mm - 115

7. The depth of descent of the tubing (shoe HKT), L, m - 1120

8. Artificial slaughter, m - 1182

9. The current face, m - 1188

10. Interval of perforation, m - 1170.4-1128

11. Aperture equipped: KG (wellhead) - "Breda" 14 _^3/4 × l0 _{a ^1/4} × 8 _^5/8 FA (Christmas tree) - "Breda" 150 × 100-140HL

12. The reservoir pressure P _PL = 2.67 MPa.

Expect:

1. The volume of blocking fluid V _BJ

V _bzh = k · h · π · D ² _sec / 4,

where k is the safety factor for the Cenomanian deposit;

k = 5-6, determined from experience in the field;

h is the distance from the upper perforations to the current face, m

h = 1188-1128 = 60 m.

V _bzh = 5 · 60 · 3,14 · 0,1534 ² / 4≈5,5 m ³ .

2. The volume of the first pack of jamming fluid V _1zhgl

V _1ggl = L · π · (D ² _sec- D ² _nct ) / 4,

V _1zhgl = 1120 · 3.14 · (0.1534 ² -0.127 ² ) / 4≈6.5 m ³ .

3. The volume of the second pack of jamming fluid V _2zhgl

V _2zhgl = (L · π · D ² _int / 4) + (h ₁ · π · D ² _vec / 4),

where h ₁ is the distance from the upper perforations to the tubing shoe, m

h ₁ = 1128-1120 = 8.0 m.

_2zhgl V = (1120 · 3.14 · 0.115 ^2/4) + (8.0 · 3.14 · 0.1534 ^2/4) ≈11,8 ^m3.

To kill the well, 5.5 m ^{3 of} blocking fluid and 18.3 m ^{3 of} kill fluid are prepared.

The jamming fluid is prepared in two portions: 10 m ³ and 8.3 m ³ .

To prepare 10 m ^{3 of} silencing liquid, water with a volume of 7.04 m ³ or 7040 l (which is 70.4 wt.%) Is poured into a 10 m ³ container (80 kg of SEANEC-TU biopolymer (which is 0.8 wt. %), 800 kg of CaCl ₂ (which is 8 wt.%), 2 m ^{3 of} diethylene glycol or 2000 l (which is 20 wt.%) And 0.08 m ³ or 80 l of Morpene (which is 0.8 wt. %). Mixing is carried out by circulation with a cementing unit CA 320. After preparation of 10 m ^{3 of the} kill fluid, it is drained into a storage tank. According to the above diagram, 9.8 m ^{3 of} kill fluid is also prepared in the following ratio of ingredients:

Diethylene glycol 1.66 m ³ or 1660 l (20 wt.%),

SEANEC-TU Biopolymer 66.4 kg (0.8 wt.%),

CaCl ₂ 664 kg (8 wt.%),

Morpen 0.0664 m ³ or 66.4 l (0.8 wt.%),

Water 5.8432 m ³ or 5843.2 l (70.4 wt.%).

The prepared solution is poured into a storage container.

1. With a closed annular space into the pipe space of the well pumped the first pack of jamming fluid with a volume of 6.5 m ³ .

2. 5.5 m ^{3 of} blocking composition is pumped into the borehole space, while the annulus is opened onto a flare line equipped with a nozzle of 8-10 mm. As a blocking composition, a composition is used consisting of 1.1 m ^{3 of} gas condensate, 1.1 m ^{3 of a} 25% aqueous solution of condensed alcohol bard sulphite, 3.3 m ^{3 of an} aqueous solution of calcium chloride with a density of 1.20 kg / m ³ and 550 kg of Policell CF filler.

3. Inject a second pack of jamming fluid with a volume of 11.8 m ³ until its first pack appears on the flare line.

4. Close the annulus and pump the remaining amount of kill fluid.

5. The well is closed for technological sludge for 12 hours and wellhead pressure is monitored.

After killing the well, repair work is carried out. Then the reservoir is released and the well is developed by two-phase foam, gradually reducing the back pressure on the reservoir until a gas influx is obtained.

As a result of the use of the well killing fluid during the repair work, the absorption of this fluid does not occur, the well’s time for pre-repair operation is reduced from 7 to 3 days.

Example 1 (laboratory).

To prepare 1000 g of muffling liquid, 791 ml (which is 79.1 wt.%) Of water, 4 g of SEANEC-TU (which is 0.4 wt.%), 145.6 ml of diethylene glycol (which is 15 wt.%) Are mixed. ) with a density of 1030 kg / m ³ , 50 g of calcium chloride (which is 5 wt.%), 4.7 ml of Morpen (which is 0.5 wt.%) with a density of 1060 kg / m ³ . Mixing is carried out until the ingredients are completely dissolved, after which the properties of the liquid are determined:

T = -15 ° C, ρ = 1005 kg / m ^3, η = 20 mPa · sec, τ = 186 dPa, θ _1/10 = 20/26 dPa, F = 1.5 cm ^3/30 minutes, β = 99.6%;

- after 3 days τ = 190 dPa, θ = ₁₀ 29 dPa, F = 1.3 cm ^3/30 minutes;

- after 6 days τ = 190 dPa, θ = ₁₀ 29 dPa, F = 1.3 cm ^3/30 minutes;

- after 9 days of τ = 187 dPa, θ = ₁₀ 26 dPa, F = 1.6 cm ^3/30 minutes;

- after 12 days τ = 185 dPa, θ = ₁₀ 24 dPa, F = 1.6 cm ^3/30 minutes;

- after 15 days τ = 185 dPa, θ = ₁₀ 24 dPa, F = 1.6 cm ^3/30 minutes;

- after 18 days τ = 184 dPa, θ = ₁₀ 24 dPa, F = 1.6 cm ^3/30 minutes;

- after 21 days τ = 183 dPa, θ = ₁₀ 24 dPa, F = 1.6 cm ^3/30 minutes.

Example 2. Prepare 1000 g of fluid for killing wells, g / wt.%:

Mc bioxan 10 / 1,0 Diethylene glycol 250/25 (use 242.7 ml
ρ = 1030 kg / m ³ ) Calcium chloride 100/10 Morpen 10/1 (use 9.4 ml
ρ = 1060 kg / m ³ ) Water 630/63

All operations are carried out as described in example 1.

Properties of killing fluids:

- on the day of preparation:

T = -30 ° C, ρ = 1020 kg / m ^3, η = 38 mPa · sec, τ = 383 dPa, θ _1/10 = 33/48 dPa, F = 0.5 cm ^3/30 minutes, β = 95.8%;

- after 3 days τ = 392 dPa, θ = ₁₀ 50 dPa, F = 0.3 cm ^3/30 minutes;

- after 6 days τ = 396 dPa, θ = ₁₀ 53 dPa, F = 0.3 cm ^3/30 minutes;

- after 9 days of τ = 391 dPa, θ = ₁₀ 50 dPa, F = 0.5 cm ^3/30 minutes;

- after 12 days τ = 389 dPa, θ = ₁₀ 50 dPa, F = 0.5 cm ^3/30 minutes;

- after 15 days τ = 385 dPa, θ = ₁₀ 48 dPa, F = 0.5 cm ^3/30 minutes;

- after 18 days τ = 385 dPa, θ = ₁₀ 48 dPa, F = 0.5 cm ^3/30 minutes;

- after 21 days τ = 382 dPa, θ = ₁₀ 48 dPa, F = 0.5 cm ^3/30 minutes.

Example 3. Prepare 1000 g of fluid for killing wells, g / wt.%:

SEANEC-TU 8 / 0.8 Diethylene glycol 200/20 (use 194.2 ml
ρ = 1030 kg / m ³ ) Calcium chloride 80/8 Morpen 8 / 0.8 (use 7.6 ml
ρ = 1060 kg / m ³ ) Water 704 / 70.4

All operations are carried out as described in example 1.

Properties of killing fluids:

- on the day of preparation:

T = -25 ° C, ρ = 1015 kg / m ^3, η = 34 mPa · sec, τ = 348 dPa, θ _1/10 = 28/37 dPa, F = 0.8 cm ^3/30 minutes, β = 97.8%;

- after 3 days τ = 360 dPa, θ = ₁₀ 42 dPa, F = 0.6 cm ^3/30 minutes;

- after 6 days τ = 361 dPa, θ = ₁₀ 42 dPa, F = 0.6 cm ^3/30 minutes;

- after 9 days of τ = 357 dPa, θ = ₁₀ 40 dPa, F = 0.7 cm ^3/30 minutes;

- after 12 days τ = 354 dPa, θ = ₁₀ 39 dPa, F = 0.7 cm ^3/30 minutes;

- after 15 days τ = 354 dPa, θ = ₁₀ 39 dPa, F = 0.7 cm ^3/30 minutes;

- after 18 days τ = 349 dPa, θ = ₁₀ 39 dPa, F = 0.7 cm ^3/30 minutes;

- after 21 days τ = 345 dPa, θ = ₁₀ 36 dPa, F = 0.8 cm ^3/30 minutes.

Example 4. Prepare 1000 g of fluid for killing wells, g / wt.%:

Mc bioxan 10 / 1,0 Diethylene glycol 250/25 (use 242.7 ml
ρ = 1030 kg / m ³ ) Calcium chloride 50/5 Morpen 10/1 (use 9.4 ml
ρ = 1060 kg / m ³ ) Water 680/68

All operations are carried out as described in example 1.

Properties of killing fluids:

- on the day of preparation:

T = -28 ° C, ρ = 1010 kg / m ^3, η = 36 mPa · sec, τ = 359 dPa, θ _1/10 = 31/43 dPa, F = 0.7 cm ^3/30 minutes;

- after 3 days τ = 372 dPa, θ = ₁₀ 45 dPa, F = 0.5 cm ^3/30 minutes;

- after 6 days τ = 375 dPa, θ = ₁₀ 46 dPa, F = 0.4 cm ^3/30 minutes;

- after 9 days of τ = 370 dPa, θ = ₁₀ 45.5 dPa, F = 0.5 cm ^3/30 minutes;

- after 12 days τ = 370 dPa, θ = ₁₀ 45 dPa, F = 0.6 cm ^3/30 minutes;

- after 15 days τ = 365 dPa, θ = ₁₀ 44.5 dPa, F = 0.6 cm ^3/30 minutes;

- after 18 days τ = 364 dPa, θ = ₁₀ 44 dPa, F = 0.6 cm ^3/30 minutes;

- after 21 days τ = 360 dPa, θ = ₁₀ 43 dPa, F = 0.7 cm ^3/30 minutes.

Example 5. Prepare 1000 g of fluid for killing wells, g / wt.%:

SEANEC-TU 7 / 0.7 Diethylene glycol 200/20 (use 194.2 ml
ρ = 1030 kg / m ³ ) Calcium chloride 70/7 Morpen 7 / 0.7 (use 6.6 ml
ρ = 1060 kg / m ³ ) Water 716 / 71.6

All operations are carried out as described in example 1.

Properties of killing fluids:

- on the day of preparation:

T = -25 ° C, ρ = 1015 kg / m ^3, η = 30 mPa · sec, τ = 312 dPa, θ _1/10 = 26/34 dPa, F = 1.0 cm ^3/30 minutes;

- after 3 days τ = 325 dPa, θ = ₁₀ 37 dPa, F = 0.8 cm ^3/30 minutes;

- after 6 days τ = 319 dPa, θ = ₁₀ 36 dPa, F = 0.8 cm ^3/30 minutes;

- after 9 days of τ = 316 dPa, θ = ₁₀ 37 dPa F = 0.9 cm ^3/30 minutes;

- after 12 days τ = 316 dPa, θ = ₁₀ 36.5 dPa, F = 0.9 cm ^3/30 minutes;

- after 15 days τ = 315 dPa, θ = ₁₀ 36 dPa, F = 1.0 cm ^3/30 minutes;

- after 18 days τ = 314 dPa, θ = ₁₀ 35 dPa, F = 1.0 cm ^3/30 minutes;

- after 21 days τ = 313 dPa, θ = ₁₀ 33.5 dPa, F = 1.0 cm ^3/30 minutes.

Thus, the claimed technical solution meets the condition of "novelty, inventive step of industrial applicability", that is, is patentable.

Table 1
ACT
laboratory tests of the claimed and known fluids for killing wells.
Tested in January 2007 Component composition, wt.% No. Xanthan Biopolymer Diethylene glycol Calcium chloride Morpen Water The freezing temperature of the composition, T, ° C one 2 3 four 5 6 7 one SEANEC-TU 0.4 15.0 5,0 0.5 79.1 - fifteen 2 MS Biomax 1,0 25.0 10.0 1,0 63.0 - thirty 3 SEANEC-TU 0.8 20,0 8.0 0.8 70,4 - 25 four MS Biomax 1,0 25 5,0 1,0 68.0 - 28 5 SEANEC-TU 0.7 twenty 7.0 0.7 71.6 - 25 6 MS Biomax 0.3 14.0 4.0 0.4 81.3 - 10 7 SEANEC-TU 1,1 26.0 11.0 1,1 60.8 - thirty 8 MS Biomax 1,0 25.0 10.0 - 64.0 - thirty 9 prototype Biopolymer Polyglycol Filtration Reducer Swelling inhibitor PH regulator Bactericide Water 0.4 1,0 1,0 1,0 0.05 0.02 Ost.

table 2 No. Properties on the day of preparation The frequency of the study, days The properties Density ρ, 3 kg / m ³ Plastic viscosity η, MPa · s Dynamic shear stress τ, dPa Static motor voltage θ, dPa after 1 min / 10 min Filter F, cm ^3/30 minutes Dynamic shear stress τ, dPa Static shear stress θ, dPa, after 10 min Filter F, cm ^3/30 minutes one 8 9 10 eleven 12 13 fourteen fifteen 16 one 1005 twenty 186 20/26 1,5 3 190 29th 1.3 6 190 29th 1.3 9 187 26 1,6 12 185 24 1,6 fifteen 185 24 1,6 eighteen 184 24 1,6 21 183 24 1,6 2 1020 38 383 33/48 0.5 3 392 fifty 0.3 6 396 53 0.3 9 391 fifty 0.5 12 389 fifty 0.5 fifteen 385 48 0.5 eighteen 385 48 0.5 21 382 48 0.5 3 1015 34 348 28/37 0.8 3 360 42 0.6 6 361 42 0.6 9 357 40 0.7 12 354 39 0.7 fifteen 354 39 0.7 eighteen 349 39 0.7 21 345 36 0.8 four 1010 36 359 31/43 0.7 3 372 45 0.5 6 375 46 0.4 9 370 45.5 0.5 12 370 45 0.6 fifteen 365 44.5 0.6 eighteen 364 44 0.6 21 360 43 0.7 5 1015 thirty 312 26/34 1,0 3 325 37 0.8 6 319 36 0.8 9 316 37 0.9 12 316 36.5 0.9 fifteen 315 36 1,0 eighteen 314 35 1,0 21 313 33.5 1,0 6 1005 12 96 9/10 6.0 3 95 10 6.0 6 93 10 6.0 9 78 8 8.0 12 75 7.5 8.0 fifteen 70 6.8 10.0 eighteen 52 5.5 12.0 21 41 4.0 16.5 7 1020 38 384 34/48 0.5 3 389.5 50.6 0.3 6 390 50,2 0.3 9 389.4 fifty 0.3 12 389 fifty 0.3 fifteen 387 49 0.3 eighteen 385 48 0.5 21 385 48 0.5 8 1020 37 381 31/45 0.5 3 350 39 0.8 6 321 35 1,5 9 272 thirty 2.0 12 250 28 2,3 fifteen 220 26 2.5 eighteen 195 25 2.5 21 168 23 2,8 9 1000 fourteen 7.6 18/21 11.6 3 9.5 27 9 6 9.0 25.5 10 9 7.5 23 11.5 12 7.5 23 11.5 fifteen 7.0 22.5 12 eighteen 6.5 22 fourteen 21 6.0 twenty fourteen

Table 3 No. Permeability, μm ² 10 ^-3 Permeability recovery coefficient, β% TO K ₁ one 17 eighteen 19 one 2,51 2.5 99.6 2 2.89 2.77 95.8 3 2.71 2.65 97.8 four 2.60 2,57 98.8 5 2,58 2,52 97.7 6 3.00 2.98 99.3 7 2.65 2,51 94.7 8 2.98 2.79 93.6 9 5.8 5.78 99.6 9 ¹ 3.14 2.79 88.8 Note: 1. Filtration, static shear stress, dynamic shear stress, and plastic viscosity were measured using a Baroid model Fann 35SA viscometer filter press. 2. Permeability recovery coefficient (defined as the ratio of core permeability after release to its permeability before pumping out the kill fluid on artificial cores with a permeability of 2.5-3.0 μm ² , simulating a reservoir of Cenomanian deposits. 3. The freezing temperature was determined in the freezer GFL-6341. 4. The action of SEANEC-TU and Bioxan biopolymers in a liquid is equivalent. 5. Microbiological destruction was determined by the change in structural and rheological properties within 21 days.

Claims (1)

Killing liquid, consisting of a xanthan biopolymer, a glycol-containing component, a filtration inhibitor, a bactericide and water, characterized in that it contains SEANEC-TU or Bioxan MS as a xanthan biopolymer, and diethylene glycol as a glycol-containing component, as a filtration reducer - calcium chloride, and as a bactericide - Morpen in the following ratio of ingredients, wt.%:
SEANEC-TU or MC Bioxan 0.4-1.0 Diethylene glycol 15-25 Calcium chloride 5-10 Morpen 0.5-1.0 Water Rest