RU2483091C1 - Drilling fluid for flushing of long-distance steeply inclined wells under conditions of permafrost and highly colloidal clay rocks, and its application method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: drilling fluid for flushing of long-distance steeply inclined wells under conditions of permafrost and highly colloidal clay rocks contains the following, wt %: clay powder 0.80-2.00; biopolymer KK Robus 0.08- 0.35; polyanionic cellulose PATS V 0.12-0.55; water-repellent fluid Sofeksil 40 0.10-0.70; lubricant KSD 1.50-10.00; water 87.79-96.20; barite weighting material 4.50-144.00 above 100. Application method of the above drilling fluid consists in the fact that the above drilling fluid with density of 1360-1420 kg/m³ is prepared for a drilling operation. It is injected into the well by being used during the drilling operation for the direction; after that, four-stage mechanical cleaning from the drilled-out rock of waste drilling mud from under the direction is performed. It is diluted with mineralised water by 2.5 times till the density is 1136-1155 kg/m³. Technological parameters of the obtained solution are measured and brought to design values by additional treatment with a number of reagents and till the ratios of the first above solution. Then, the obtained solution is injected into the well by being used during the drilling operation for the conductor; after that, four-stage mechanical cleaning from the drilled-out rock of waste drilling mud from under the conductor is performed. It is diluted with mineralised water by 1.7 times till the density is 1070 kg/m³, technological parameters of the obtained solution are measured and brought to design values by additional treatment with a number of reagents and till the ratios of the first above solution. It is used for drilling under an intermediate and production string. Then, four-stage mechanical cleaning from the drilled-out rock of waste drilling fluid is performed again. It is treated with barite weighting material till the density is 1800 kg/m³, its technological parameters are measured and brought to design values by additional treatment with a number of reagents and till the ratios of the first above solution. That solution is used for drilling under the shank.

EFFECT: creation of polymer-clay solution with pseudoplastic properties and controlled density to maintain stability of the well walls under conditions of permafrost formations complicated with gas-hydrate accumulations, enlarging the area of its application for drilling of intrapermafrost intervals composed of highly colloidal clay deposits due to additional provision of high inhibiting, lubricating properties; reduction of water consumption volumes, drilling wastes and consumption of reagents.

2 cl, 4 tbl, 2 dwg

Description

The invention relates to the drilling of oil and gas wells, in particular to the compositions of polymer clay solutions used in permafrost (MMP) and highly colloidal clay rocks and washing methods with their use.

The practice of drilling wells under conditions of permafrost and clayey rocks shows that under these conditions, polymer clay solutions with a low solids content are most widely used, as the most economical and quite effective, and their improvement is relevant.

Known pseudoplastic solution (patent RU 2254353) for drilling MMP, salt-resistant and resistant to mechanical degradation, reducing the meltability of MMP at a positive temperature during drilling, including bentonite clay powder, water-soluble polymer Praestol brand 2530, high viscosity polyanionic cellulose, with the following ratio of high viscosity components. %:

Bentonite Clay Powder 2,000-4,000 Praestol brand 2530 0,020-0,060 PAC B 0.250-0.400 Water 95,730-97,540

However, this solution does not have good inhibitory, with respect to clay deposits, as well as lubricating properties, which interferes with its effective use for drilling long-length steeply directed wells in conditions of highly colloidal clay deposits.

Closest to the claimed solution is a polymer clay solution (patent RU 2274651) for drilling in MMP, consisting of clay, a stabilizer in the form of a mixture of a polysaccharide reagent and structurant, hydrocarbon antifreeze and water, it contains Acinetobacter Sp. Biopolymer as a polysaccharide reagent, and in the quality of the builder - condensed sulfite-alcohol vinasse KSSB in the following ratio of ingredients, wt.%:

Clay 6,000-8,000 KSSB 4,000-6,000 Acinetobacter Sp. Biopolymer 2,000-4,000 Hydrocarbon Antifreeze (Urea or Glycerin) 7,000-19,000 Water Rest

Moreover, the ratio of parts by weight Biopolymer Acinetobacter Sp. and KSSP is 1: 1-3, respectively.

Although this solution has improved pseudoplastic properties, low filtration, and a low melting rate of MMP, its maximum density is 1090 kg / m (examples 3, 6), and high rheological parameters of the solution do not allow its further increase. It is known that the geological and technical conditions of the deposits of the Yamal Peninsula (Bovanenkovo, Kharasavey) in the MMP interval are complicated by gas hydrate deposits, which create an anomaly coefficient of 1.35 / VL Bondarev et al. Gas chemical characteristics of the supranomanian deposits of the Yamal Peninsula (as an example Bovanenkovo oil and gas condensate field) / Geology, Geophysics and Development of Oil and Gas Fields, 2008, No. 5, - p.22-33 /. For the prevention of gas occurrences under these conditions, it is necessary that the drilling fluid has an increased density (up to 1420 kg / m ³ ).

A significant disadvantage of the known solution is that the biopolymer used in its composition is a liquid, which makes it difficult to transport it to the inaccessible northern areas of drilling operations, which are characterized by the presence of permafrost. To reduce the freezing temperature, hydrocarbon antifreeze is introduced into the reagent in an amount of 7 to 19 wt.%, Which significantly increases the cost of the solution, and its freezing temperature is reduced to a maximum of -12 ° C (examples 1-10 of the patent RU 2274651), which is clearly not enough for the conditions of the Far North.

Known compositions of the fluids are intended only for permafrost in the interval 0-550 m (conductor), then drilling to the design depth is carried out with the replacement of the drilling fluid (page 6 of the patent specification RU 2274651).

The closest solution to the claimed one for conditions of collapsing rocks and opening of reservoirs is a drilling fluid (patent RU 2242492) containing clay, a stabilizing reagent, polyglycol, an inhibitory additive and water. As an inhibitory additive, it contains the KOLPAN potassium-polyacrylate reagent and optionally the Sonbur-1101 lubricant additive, a condensation product of monoethanolamine and crude tall oils mixed with kerosene, monoethanolamine and oxal and a surfactant of the PKD-515 brand in the following ratio of ingredients, wt .%:

Clay 2.00-5.00 Polyglycol 1.00-3.00 Reagent stabilizer 0.50-1.00 Lubricant additive Sonbur-1101 0.50-1.00 Surfactant brand PKD-515 0.50-1.00 Potassium Polyacrylate Reagent KOLPAN 3.00-5.00 Water Rest

The drilling fluid may further comprise an acid-soluble carbonate weighting agent in an amount of from 45.00 to 50.00 wt.%.

The positive qualities of the well-known solution (high lubricating and anti-seizing properties, inhibitory ability, high heat resistance, high coefficient of restoration of the initial permeability), which are proved in the description of the patent, will contribute to its high efficiency for use in drilling vertical wells in the presence of clay deposits and opening layer. However, the low rheological parameters of this solution do not allow sludge to be removed from steeply directed long-drawn shafts and will not contribute to a decrease in the thawability of the permafrost.

There is also a known method of using drilling fluids for drilling wells in the waters of the Tazovskaya and Ob gulfs, which consists in using a newly prepared drilling fluid (new composition) for each drilling interval, depending on the design of the well: direction and conductor - polymer clay (Direction: PBMA 2, 00; KK “Globus” 0.25; P PAC N 0.50; “Silange” 0.50; “SMEG-3” 1.00; Pentax 0.20; micromarble 5.00; “Remacid” 0.10; caustic soda 0.10; water - the rest. Conductor: clay powder PBMA 2.00; KK “Globus” 0.25; P PAC N 0.35; FHLS 2.00; GKZH-10 BSP 0.30; "Silange" 0.50; "SMEG-3" 1.00; Pentax 0.20; micromarble 5.00; "Remacid" 0.10; caustic soda 0.10; rest water); the intermediate column is slightly silicate (PBMA 0.2 clay powder; KK Globus 0.2; P PAC N 0.3; Monasil 3.5; Pentax 0.2; Silange 0.8; SMEG-3 1, 5; KSD 0.5; FHLS 2.0; GKZH - 10 BSP 0.3; “Remacid” 0.1; water - the rest); production casing and liner - clay-free clay mineralized (SC “Globus” 0.35; P PAC N 0.40; “Monasil” 3.50; Pentax 0.20; “Silange” 0.80; “SMEG-3” 1.50 ; KSD 0.50; FHLS 2.00; GKZh - 10 BSP 0.30; “Remacid” 0.10; marble chips 5.00; water - the rest) / R Gazprom 2-3.2-269-2008. Compositions of drilling fluids and circulation modes for drilling wells in the waters of the Taz and Ob gulfs. - M.: Gazprom Expo, 2009 .-- 33 p. /. These compositions of the solutions are able to ensure trouble-free drilling of long wells from the coastal zone in the fields in the Tazovskaya and Ob Bay, however, the method of their application leads to large volumes of water consumption, the formation of a significant amount of drilling waste, which depend on the design of the well and can be up to 1858 m and large reagent consumption.

The objective of the invention is to maintain the stability of the walls of the borehole during drilling of MMP complicated by gas hydrate deposits, as well as rocks piled with highly colloidal clay deposits, and to reduce the amount of water consumption and drilling waste when drilling long-length steeply directed wells.

The technical result provided by this invention is the creation of a polymer clay solution with pseudoplastic properties and adjustable density to maintain the stability of the borehole walls in the conditions of permafrost conditions complicated by gas hydrate deposits, expanding its field of application for drilling sub-permafrost intervals composed of highly colloidal clay deposits, due to the additional provision of high inhibitory lubricating properties, the method of application of which provides a reduction in water consumption, thodov drilling reagent consumption.

The task and technical result are achieved in that the drilling fluid for flushing long-length steeply directed wells in the conditions of permafrost and highly colloidal clay rocks consists of clay powder, water and additives in the following ratio of components, wt.%:

Clay powder 0.80-2.00 Biopolymer "KK Globus" 0.08-0.35 PAC B polyanionic cellulose 0.12-0.55 Water-repellent fluid "Sofexil 40" 0.10-0.70 KSD lubricant additive 1,50-10,00 Water 87.79-96.20 Barite weighting agent 4.50-144.00 in excess of 100

and the method of using the drilling fluid for flushing long-length steeply directed wells in the conditions of permafrost and highly colloidal clay rocks is that for drilling the drilling fluid according to claim 1 with a density of 1360-1420 kg / m ³ is prepared, injected into the well, using when drilling under the direction after which a 4-stage mechanical cleaning of the cuttings spent from the direction of the drilling fluid is carried out, diluted with mineralized water 2.5 times to a density of 1136-1155 kg / m ³ , the technologist is measured physical indicators of the resulting solution and bring them to design values by further processing the assortment of reagents and to the ratios of the solution according to claim 1, then inject the resulting solution into the well, using it to drill under the conductor, then carry out a 4-stage mechanical cleaning of cuttings from - under the mud conductor, dilute it with mineralized water 1.7 times to a density of 1070 kg / m ³ , measure the technological parameters of the resulting solution and bring them to design values by adding working with an assortment of reagents up to the ratio of the mortar according to claim 1 and using it for drilling under the intermediate and production casing, again carry out a 4-step mechanical cleaning of the drilled rock of the spent drilling fluid, treat with a barite weighting agent to a density of 1800 kg / m, measure its technological parameters and bring them to design values by further processing the assortment of reagents and to the ratio of the solution according to claim 1, this solution is used for drilling under the shank.

Laboratory experiments to develop the inventive drilling fluid composition were performed using the following materials and reagents: Bentocon-based clay powder with a yield of 18.7 m ³ / t according to TU 5751-006-70896713-2005 Bentoprom LLC (Stary Oskol) , powdered biopolymer KK Globus according to TU 2458-011-35944370-2007 ZAO NPO Promservice (Chuvashia), polyanionic cellulose Polycell PAC according to TU 2231-015-32957739-80 ZAO Polytsell (Vladimir), hydrophobizing liquid Sofexil 40 according to TU 2229-008-42942526-00 CJSC NPK SOFEX (Moscow), CJSC NPK SOFEX (Moscow), powder comp eksnoy lubricating additives RACs TU 2458-013-35944370-2008 Company "NPO Promservice" (debugging) and barite weighting agent in accordance with GOST 4682-84 ZAO "barite" (Khakassia).

For experimental verification of the inventive drilling fluid in laboratory conditions, five formulations were prepared (see table 1). The technology of their preparation is as follows. 800 ml of water is poured into a glass of the Voronezh mixing plant and the calculated amount of clay powder is introduced into it. The solution is left for 24 hours at room temperature to hydrate and swell the clay particles, then mix for one hour at a speed of 3000 rpm. The resulting clay suspension is treated with a calculated amount of polymers with additives and mixed on a mixer at the same speed for 30 minutes, after which it is processed with a weighting agent and its technological parameters are measured on standard instruments at 20 ° C. The parameters of the solutions of the prototypes are taken from the descriptions of the inventions. An analysis of the results shows that, with an optimal ratio of components in the solution (solutions 1, 2, 3 of the claimed composition), it has the necessary density from 1070 to 1800 kg / m ³ , high rheological parameters (η = 19.5-90.0 mPa · s, τ ₀ = 100-175 dPa), low non-linearity index (0.49-0.57), low clayey stickiness coefficient (according to the FSK-4 device 0.09-0.25), low filtration (2.0 -3.0 cm ^3/30 min) that allows the use of this solution for drilling MMPs, including complicated gas hydrates and clayey sediments under dlinnopro heavy directional wells.

Table 2 illustrates the method of application of the inventive drilling fluid composition at drilling intervals, which was carried out in laboratory conditions.

The main factors determining the requirements for substantiating technological parameters of drilling fluids are lithological and mineralogical characteristics of rocks, thermobaric drilling conditions, well designs and wellbore profiles from technical and technological solutions for well construction from the coastal zone under the Kara Sea.

The main complications when drilling under the direction (the first section) are the thawing of high-icy permafrost, collapses of walls in the quicksand zone, gas manifestations when opening gas hydrate deposits, collapses of sludge from caverns, polymineral aggression of cryopegs, water manifestations and absorption of the drilling fluid. As a result of the use of large diameter bits (490 mm) for drilling IMF, the effect of the arch effect decreases and the stability of the walls of the well decreases. To prevent these complications, you must:

- reduce heat erosion destruction of the walls of the borehole by optimizing the rheological properties and temperature of the drilling fluid;

- to increase the weighing (transporting) ability of the drilling fluid by optimizing its viscosity and structural-mechanical properties;

- provide backpressure (repression) on the walls of the borehole by optimizing the density of the solution to prevent formation fluids from the IMF (gas, brines, water) and compensate for the reduction of the arch effect.

In order to prevent thermal erosion destruction of the walls of the well, to ensure the transportation of cuttings along the wellbore, to prevent gas formation as a result of hydration, to reduce the aggression of salt-saturated formation fluids, the cooled drilling fluid must have the following basic structural, mechanical, rheological and filtration properties when drilling in the direction:

- density from 1360 to 1420 kg / m ³ ;

- static shear stress for 1 min at least 60 dPa;

- dynamic shear stress up to 230 dPa;

- plastic viscosity up to 35 MPa · s;

- static filtration rate of 6.5 cm ^3/30 min.

The main complications when drilling an oblique directional bore under the conductor (second section) are the formation of troughs during thawing of frozen clay and waterlogging of the borehole walls, gland formation during dispersion of highly active montmorillonite rocks, gas manifestations when opening gas hydrate lenses, the formation of "slurry" cushions on the dune tilt angle of more than 45 °. To prevent possible complications when drilling under the conductor, you must:

- to ensure the transport of sludge along an inclined directional shaft by optimizing the rheological and structural-mechanical properties of the drilling fluid through the use of high molecular weight reagents of multifunctional action;

- improve the lubricating properties of the drilling fluid for the prevention of sticking of the drilling tool and the transmission of axial load on the bit due to the use of lubricating additives with an inhibitory effect;

- to limit the impact of the dispersion medium of the drilling fluid on clay rocks and cuttings cuttings by reducing the filtration rate and the use of inhibitory polymer additives in the composition of the drilling fluid.

To ensure the transport of sludge and the cleaning of an inclined directional shaft, to prevent sticking of a drilling tool, to reduce the hydration of clay rocks during drilling of deposits of the Tibeysalinsky, Gankinsky, Berezovsky suites, the drilling fluid must have the following indicators of the main technological properties:

- density from 1136 to 1155 kg / m ³ ;

- static shear stress for 1 min at least 35 dPa;

- static shear stress for 10 min at least 50 dPa;

- plastic viscosity up to 22 MPa · s;

- dynamic shear stress up to 190 dPa;

- static filtration rate not more than 4 cm ^3/30 min;

- the stickiness coefficient of the filter cake is not more than 0.15.

The third section is confined to the interval for drilling under the intermediate string in the sediments of the Marreselinsky and Yarong Formations and to the interval for drilling for the production string in the deposits of the Tanopcha Formation. The maximum length of the “open” bore when drilling under an intermediate string reaches 2900 m, while drilling for production - 1100 m (wells on formations TP _1-5 with a deviation coefficient of 2.92). The main complications during the drilling of this area are sludge accumulation, step- and groove formation, landing, tightening, sticking of a drilling tool, and absorption of drilling fluid at the boundary of lithologically heterogeneous rocks. The large length of the “open” bore with an angle of inclination of 50.2 ° to 86.7 °, as well as the high contact forces of the tooling elements of the drill and casing strings on the inner walls of the cased and uncased parts of the barrel make it difficult to transfer axial load to the bit and increase the risk of “under-clearance” »Casing to the design depth. For the prevention of possible complications when drilling under an intermediate string (formations TP _1-5 , TP ₁₀ , TP ₁₁ , TP ₂₆ , BY ₁ , BY ₂ ) and when drilling under a production string (formations PK ₁ , TP _1-5 , TP ₁₀ , TP ₁₁ , TP ₂₆ , BY ₁ , BY ₂ ) is necessary:

- to ensure the formation of a quality trunk and long-term stability of the walls of the well by protecting rocks from hydration (swelling) through the use of special components of drilling fluids with a high inhibitory effect;

- to ensure the transport of cuttings along a long trunk to prevent its accumulation on the bottom wall of the trunk by increasing the weighing ability of the drilling fluid through the use of reagents with pseudoplastic and structure-forming action;

- reduce the stickiness of the filter cake and the coefficient of friction at the metal-metal contact to the minimum possible values that ensure the transmission of the axial load on the bit and the prevention of sticking of the drilling tool and the descent of the casing to the design depth;

- to optimize the composition of the drilling fluid to control its properties in conditions of prolonged circulation by using reagents that are resistant to mechanical degradation.

When drilling the third section for safe opening of formations, the density of the solution should be: formation PK ₁ from 1150 kg / m ³ , formations of the Tanopchinsky suite (except TP ₂₆ ) from 1070 kg / m ³ . Additional requirements for the technological properties of the drilling fluid (in comparison with the conductor), aimed at preventing complications during drilling of the third section, are as follows:

- figure static filtering is not more than 3 cm ^3/30 min;

- coefficient of friction "metal - metal" not more than 0.1;

- the stickiness coefficient of the filter cake from 0.1 to 0.2.

The remaining indicators (static shear stress, dynamic shear stress, plastic viscosity) of the drilling fluid during drilling of the third section remain within the limits indicated for drilling under the conductor. The range of components used in the drilling fluid also does not change. The main components are multifunctional reagents - PAC polysaccharide cellulose and KSD lubricant additive.

The opening of productive formations TP ₂₆ , BY ₁ , BY ₂ (the fourth section) is carried out by an inclined horizontal shaft with an anti-aircraft angle of up to 84.2 °, with the descent of the filter shank. The length of the trunk in productive formations is from 640 m (TP ₂₆ ) to 1600 m (BY ₁ , BY ₂ ). The temperature of the rocks in the reservoir is 90 ° C to 95 ° C. The reservoir pressure anomaly coefficient varies from 1.71 (TP ₂₆ reservoir) to 1.83 (BY ₂ reservoir). With this in mind, the density of the drilling fluid should have values up to 1800 kg / m ³ (reservoir TP ₂₆ ). Weighted drilling fluid should have the following structural-mechanical and rheological properties:

- static filtration rate not more than 3 cm ^3/30 min;

- static shear stress (CHC _1/10 ) not more than 60/90 dPa;

- plastic viscosity up to 90 MPa · s;

- dynamic shear stress up to 190 dPa.

For drilling a well, a composition solution is prepared, wt.%: Clay powder 2.00; biopolymer KK Globus 0.12-0.15; PAC polyanionic cellulose B 0.12-0.15; KSD lubricant additive 1.5; "Sofexil 40"0.10; water 96.16-96.10; barite weighting agent 50.00-62.00 (over 100) with a density of 1360-1420 kg / m ³ with the technological parameters indicated in table 2 (solutions 1, 2).

A solution for drilling under a conductor in order to reduce drilling waste and water consumption was obtained by diluting 2.5 times the solutions (compositions 1, 2) with mineralized (3% NaCl) water (to prove the possibility of using sea water) to a density of 1115-1136 kg / m ³ . The technological indicators of this solution were measured, which showed their inconsistency with the designed ones: ρ = 1115-1136 kg / m ³ ; F = 14 cm ^3/30 min; CHC _1/10 = 0/0; η = 2.5 MPa · s; τ ₀ = 16.8 dPa, after which the solution is further processed to the required technological parameters: ρ = 1115-1136 kg / m ³ ; F = not more than 4 cm ^3/30 min; SNA _1/10 = not less than 35/50; η = up to 22 MPa · s; τ ₀ = up to 190 dPa. Or, in quantitative terms, the solution is additionally treated with reagents, wt.%: Kobus biopolymer 0.26-0.29; PAN polyanionic cellulose H 0.45-0.49; KSD lubricant additive 1.24-1.50; hydrophobizing liquid "Sofexil 40" 0.20. Repeated measurement of technological indicators (compositions 3, 4) showed that they are within the design limits. When washing a production tubing and the intermediate solution from the conductor (formulations 3, 4) is subjected to 1,7-fold dilution to ρ = 1070 kg / m ^3, its technological parameters are measured: F = 10 cm ^3/30 min; φ _ck = 0.3; φ _Tr = 0.5; SNA _1/10 = 0/0 dPa; η = 2.0 MPa · s; τ ₀ = 15 dPa. The measurement results show their mismatch with the required, the solution is further processed with reagents, wt.%: Clay powder 0.5; KSD lubricant additive 8.8-9.0; "Sofexil 40" 0.4 to the technologically required indicators: ρ = 1070-1150 kg / m ³ ; F = 2.3 cm ^3/30 min; SNA _1/10 = 24 / 60-23 / 37 dPa; η = 22.5-28 MPa · s; τ ₀ = 125-172 dPa; φ _ck = 0.19-0.2; φ _Tr = 0.02-0.025 (compositions 5, 6), which are within the limits of the designed.

To open the reservoirs with AVPD (TP ₂₆ , BY ₁ , BY ₂ ), the drilling fluid from under the production string is weighted with barite to a density of 1800 kg / m (composition 7). Measurement of its technological indicators after weighting shows compliance with the design: ρ = 1800 kg / m ³ ; F = 2.4 cm ^3/30 min; SNA _1/10 = 34/67 dPa; η = 85 MPa · s; τ ₀ = 172 dPa.

It is assumed that the technology for cleaning drilling fluids and the completeness of equipment during well construction complies with STO Gazprom 2-3.2-198-2008 / Guidelines for the technology for cleaning drilling fluids during well construction in the fields of the Tyumen Region. - M.: IRC Gazprom, 2008 /.

A four-stage drilling fluid cleaning system with additional cleaning agents is recommended, including:

- vibrating sieves;

- sand separator;

- desilter;

- a centrifuge to separate the solid phase;

- additional cleaning agents: sieve-hydrocyclone separator; conveyor separator.

The required mesh sizes of vibrating sieve screens, the diameters of the sand nozzles of the sand separator and desilter, as well as the centrifuge operating mode to ensure high-quality cleaning of drilling fluids and maintain their design parameters, are presented in table 3.

The inhibitory ability of a drilling fluid intended for conductor drilling was evaluated using OFITE dynamic swelling dynamic tester at a temperature of 25 ° C relative to a clay sample with a yield of 2.4 m ³ / t, according to the mineralogical composition close to the cuttings of the northern deposits. The test results are presented graphically (figure 1). It was found that the swelling (K) of the clay material in the developed solution (curve 2) in comparison with the swelling in distilled water (curve 1) is reduced by 3 times, which confirms the fact that the solution has good inhibitory properties.

The inhibitory ability of drilling fluids for intermediate and production casing was assessed using the OFITE tester in dynamic mode at t = 80 ° C (temperature as close as possible to reservoir conditions). There is a decrease in swelling in the developed solutions with a density of 1.07 (curve 4), a density of 1.15 (curve 3), a density of 1.80 (curve 1) compared with swelling in distilled water up to 4-5 times (figure 2).

Comparison of the proposed method of applying the drilling fluid with the well-known / R Gazprom 2-3.2-269-2008. Compositions of drilling fluids and circulation modes for drilling wells in the waters of the Taz and Ob gulfs. - M: Gazprom expo, 2009. - 33 pp. / By calculating the required volume of drilling fluid for drilling wells in the reservoirs of formations BY ₁ and BY ₂ with a deviation coefficient of 3.89 and a trunk length of 9806 m for the structures shown in table 4, according to the methodology for calculating the volume of drilling fluids for well construction in the fields of the Tyumen region / R Gazprom 2-3.2-198-2008. Guidance on the technology for cleaning drilling fluids during well construction in the fields of the Tyumen region. - M .: IRC Gazprom, 2008 / showed that the proposed method of using the inventive drilling fluid can reduce its volume by 44%, and consequently, the volume of water consumption and generated drilling waste, as well as save chemicals.

Thus, the claimed composition and method of using a drilling fluid with highly rheological properties based on the same dispersion medium with the same assortment of components provides the ability to control the technological parameters of the drilling fluid for conducting long sections of the wellbore with a large angle of inclination and lowering the casing strings to design marks, significantly reducing water consumption and drilling waste, as well as chemicals.

Table 3 Sieve sizes of mesh panels, diameters of sand nozzles and centrifuge operating mode Drilling interval, m The mesh size of the sieve panels, mm Diameter of sand nozzles, mm Centrifuge Mode conveyor separator SVL GHS sand divider septic tank solid separation rpm m ³ / h 0-140 (20) direction 140 (200) -665 (720) conductor 0.9 × 0.9 0.5 × 0.5 0.071 × 0.071 22-25 8-10 1700-2200 15-18 665 (720) -1360 prom. column - 0.4 × 0.4 0.071 × 0.071 16-18 8-10 1700-2200 15-18 1360-2900 (4250) expl. column - 0.25 × 0.25 0.071 × 0.071 16-18 8-10 1700-2200 15-18

Table 4 Well Designs for a Formation Bed BB ₁ and BB ₂ Name of casing Casing Characteristics The interval of descent of the casing strings along the bore (vertical), m, with a deviation coefficient of 3.89 Diameter mm Wall thickness mm Direction 426 10.00 0-140 Conductor 324 9.50 0-1312 (0-720) Intermediate 245 10.03 0-797 (0-619) 8.94 0-4573 (0-1360) Operational 178 11.50 0-250 11.50 250-797 (250-619) 9.19 797-8343 (619-2100) Shank Filter 127 FB-127 9.19 7808-9806 (1995-2385) 9.19 9806-9956 (2385-2400) Lift 89 7.34 0-797 (0-619) 6.45 797-7808 (619-1995) 6.45 7808-9806 (1995-2385)

Claims (2)

1. Drilling fluid for flushing long-length steep wells in permafrost and highly colloidal clay rocks, consisting of clay powder, water and additives in the following ratio of components, wt.%:
clay powder 0.80-2.00; KK Globus biopolymer 0.08-0.35; PAN B polyanionic cellulose 0.12-0.55; water-repellent fluid "Sofexil 40" 0.10-0.70; KSD lubricant additive 1.50-10.00; water 87.79-96.20; barite weighting agent 4.50-144.00 in excess of 100 2. The method of application of the drilling fluid for washing long-length steeply directed wells in the conditions of permafrost and highly colloidal clay rocks, which consists in the fact that for drilling the drilling fluid according to claim 1 with a density of 1360-1420 kg / m ³ is prepared, injected into the well, using while drilling under the direction, after which a 4-step mechanical cleaning of the cuttings spent from the direction of the drilling fluid is carried out, diluted with mineralized water 2.5 times to a density of 1136-1155 kg / m ³ , the tech the biological parameters of the resulting solution and bring them to design values by further processing the assortment of reagents and to the ratios of the solution according to claim 1, then inject the resulting solution into the well, using it to drill under the conductor, then carry out a 4-stage mechanical cleaning of the cuttings from under the mud conductor, dilute it with mineralized water 1.7 times to a density of 1070 kg / m ³ , measure the technological parameters of the resulting solution and bring them to the design values m of additional processing with the assortment of reagents and to the ratio of the mortar according to claim 1 and using it for drilling under the intermediate and production casing, again carry out a 4-step mechanical cleaning of the cuttings of the spent drilling fluid, treated with barite weighting agent to a density of 1800 kg / m ³ , measure its technological parameters and bring them to design values by further processing the range of reagents and to the ratio of the solution according to claim 1, this solution is used for drilling under the shank.

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