RU2274651C1 - Polymer-clay fluid for drilling well in permafrost rock - Google Patents

Abstract

FIELD: petroleum and gaseous industry.

SUBSTANCE: invention relates to drilling oil and gaseous wells, in particular, to polymer-clay fluids for drilling used under conditions of permafrost rocks. Proposed polymer-clay fluid shows the improved pseudoplastic properties providing enhancing retaining and transporting capacity and treatment degree of the well walls, diminished filtration due to high rate in formation of low-penetrable filtration crust preventing the well pollution and promoting to retention of its collector properties, reduced rate of warming up of permafrost rocks that prevents formation of caverns and destruction of the well walls and as result provides prolonged retention of the well trunk in the stable state. Polymer-clay fluid for wells drilling in permafrost rocks doesn't freeze at negative temperatures and comprises clay, stabilizing agent as a mixture of polysaccharide reagent and structure-forming agent, hydrocarbon antifreeze and water. As a polysaccharide reagent the polymer-clay fluid comprises Acinetobacter sp. biopolymer, and as a structure-forming agent it comprises condensed sulfite-alcohol distillery grains in the following ratio of components, wt.-%: clay, 6-8; condensed sulfite-alcohol distillery grains, 4-6; Acinetobacter sp. biopolymer, 2-4; hydrocarbon antifreeze, 7-19, and water, the balance, wherein the ratio of Acinetobacter sp. biopolymer and condensed sulfite-alcohol distillery grain = 1:(1-3) mas. p., respectively. As hydrocarbon antifreeze, polymer-clay fluid comprises carbamide or glycerol. Invention provides enhancing effectiveness in drilling of wells in permafrost rocks.

EFFECT: improved properties of polymer-clay fluid.

2 cl, 15 ex

Description

The invention relates to the drilling of oil and gas wells, in particular to polymer clay solutions (PGR) for drilling, used in permafrost.

Analysis of the current level of technology showed the following:

known drilling mud for drilling wells in the North, containing the following components, wt.%:

Clay bentonite 5-6 Carboxymethycellulose-600 1-1,2 Sodium Acetate 16-17 Water Rest

(see USSR AS No. 812823 dated 04/09/1979, class C 09 K 7/02, published in OB No. 10, 1981). Sodium acetate is an antifreeze.

The disadvantage of this drilling fluid is the low efficiency of drilling wells in permafrost. This is due to the following reasons: the drilling fluid is characterized by worsened pseudoplastic properties, which lead to reduced holding and transporting abilities, the degree of cleaning and removal of cuttings from the well. This is due to the low structural and rheological properties (static and dynamic shear stress). The drilling fluid is characterized by increased filtration as a result of the delayed formation of a filter cake, which is also highly permeable. This is due to the insufficient content of carboxymethyl cellulose-600 in solution at a high content of sodium acetate. The penetration of the liquid phase and solid particles of the drilling fluid into the formation and, as a result, pollution and a decrease in its reservoir properties. The increased rate of thawing of permafrost in the near-stem zone is due to the component composition, in particular, the presence of a higher content of antifreeze - sodium acetate, which sufficiently reduces the freezing point of the solution and interacts with ice with the destruction of the latter, as well as a low content of carboxymethyl cellulose-600, which can lead to the formation of caverns and violation of the integrity of the walls of the well. In turn, the latter does not provide long-term preservation of the wellbore in a stable state;

A drilling fluid is known containing the following components, wt.%:

Clay 28-49 Reagent stabilizer 0.3-2.0 Glycerol production waste at the final stage 0.25-3.00 Water Rest

(see USSR AS No. 1640137 dated 06/01/1988, class C 09 K 7/02, published in OB No. 13, 1991). Use a reagent - stabilizer in the form of a mixture of condensed sulfite - alcohol stillage KSSB-2 and carboxymethyl cellulose.

The disadvantage of this drilling fluid is the low efficiency of drilling wells in permafrost. This is due to the following reasons: the disadvantages of the drilling fluid include its increased filtration (up to 20 cm ³ ) and the high rate of thawing of permafrost. Despite the high rheological parameters (conditional viscosity and static shear stress), sufficient pseudoplastic properties, which determine the holding and transporting abilities, its use is inappropriate for drilling wells in permafrost. High filtration values are associated with a low rate of formation of the filter cake and lead to the loss of a certain volume of the solution due to filtration into the formation, which, in addition to contaminating the latter and reducing its reservoir properties, thickens the drilling fluid and causes difficulties in pumping it. With a high initial density of the solution (up to 1450 kg / m ³ ) due to the loss of the liquid phase due to filtration, its density increases even more, contributing to the growth of dynamic resistance during pumping and difficulties in the operation of the equipment. The high density of the solution activates the process of penetration of the filtrate into the pore space of permafrost, increases the area and depth of its physico-chemical effect on ice, thereby contributing to the softening of the rock, loss of stability and destruction of the walls of the well. The high rate of thawing of permafrost is also due to the insufficient amount of stabilizer in the composition of the drilling fluid, which reduces the heat transfer coefficient. In addition, the low content of glycerin production antifreeze waste in the drilling fluid composition does not provide the necessary freezing temperature. The latter leads to cavern formation and destruction of the walls of the well and, as a result, does not provide long-term preservation of the wellbore in a stable state, which indicates the problematic use of this drilling fluid for drilling wells in permafrost;

There is a method of drilling wells in permafrost using a drilling fluid containing the following ingredients, wt.%:

Clay bentonite 5.5 Dispersant Reagent (ethylene glycol) 5,6 Xanthomonas campestris biopolymer, crosslinked with chrome aluminum agent 0.5 Water Rest

(see US patent No. 3633689 dated 05/27/1970, class E 21 B 21/04, publ. 11/01/1972 g).

The disadvantage of this drilling fluid is the low efficiency of drilling wells in permafrost. This is due to the following reasons: despite the low freezing temperature, the drilling fluid has low pseudoplastic properties. The insufficiently high pseudoplastic properties of the solution are due to the low content of clay and biopolymer in the composition, which does not make it possible to provide the necessary rheological parameters for realizing the holding and transporting abilities of the drilling fluid and the high degree of purification of the well from drill cuttings due to the alignment of the profile of fluid flow rates in the annulus. Increased filtration of the drilling fluid is associated with a low rate of formation of the filter cake, which is highly permeable both because of the insufficient content of the biopolymer and because of its use in the crosslinked chromium-aluminum cations form, which complicates the diffusion of this component and its adsorption on the well walls. The increased thawing rate of permafrost is due to the physicochemical interaction of the ethylene glycol used with ice, which causes the destruction of the latter even at low temperatures. In this case, as a result of thawing of the ice composing the borehole walls, they are destroyed with the formation of caverns, which does not ensure the preservation of the borehole in a stable state. In addition, the disadvantages of this drilling fluid include the high cost and enzymatic instability of the Xanthomonas campestris biopolymer, which requires the addition of bactericides, which leads to an increase in the cost of preparing the mud.

This PGR is not indicated as the closest analogue - the prototype due to the fact that the patent does not provide indicators of the static shear stress and filtration of the PGR, the rate of destruction of ice when exposed to the ingredients of the PGR. Testing the formulation of this analogue in the laboratory of the applicant for comparison with the claimed technical solution without knowledge of information such as "know-how" is not possible. In this regard, the following evaluation of the technological properties of the analogue under consideration was carried out according to the data available in the patent description and the proposed indicators, theoretically justified from the information about the PGR presented in the description.

PGR used as a prototype for drilling in permafrost rocks, containing clay powder, a stabilizer in the form of a mixture of a polysaccharide reagent - carboxymethyl cellulose KMTs-600 and a structuring agent - sodium carbonate, hydrocarbon antifreeze and water in the following ratio of ingredients, wt.%:

Clay powder 3.0 Carboxymethycellulose-600 0.2-0.5 Sodium carbonate 0.2 Urea 5.0-26.4 Water Rest

(see Flushing media for drilling holes in frozen rocks and ice. / V.K. Chistyakov, P. G. Talalay, A. A. Yakovlev, AM Yakovlev. - Review. Inform. Ser. Technique, technology and organization of exploration . - M.: ZAO "Geoinformmark", 1999. - Issue 2. - S.28-29).

The disadvantage of this PGR is the low efficiency of drilling wells in permafrost. This is due to the following reasons: despite the low freezing temperature, the solution has reduced pseudoplastic properties. Low pseudoplastic properties are due to its rheological characteristics: low values of plastic viscosity, as well as dynamic and static shear stress, which does not ensure the holding and transporting abilities of the specified solution, cleaning wells from cuttings. Quantitative composition and proportion of ingredients allow to obtain a solution does not freeze at low temperatures the system, which nevertheless has high filtration (10 cm ^3/30 min). The formation of a permeable filter cake formed from particles of the dispersed phase occurs rather slowly due to the low content of clay powder and stabilizer, especially the polysaccharide reagent - carboxymethyl cellulose-600, which prevents the filtrate from penetrating frozen ground and erosion of thawed particles during hydrodynamic effects of the circulation flow on the walls of the well. As a result, the formation is contaminated with the filtrate and solid particles of the dispersed phase — a decrease in its reservoir properties and well productivity. The high rate of thawing of permafrost during the circulation of PGR is due to the combination of ingredients used: carbamide and sodium carbonate, each of which is antifreeze. The intensity of ice destruction, which determines the rate of thawing of permafrost, increases significantly in the presence of sodium carbonate, which leads to softening of polydisperse permafrost, the loss of their stability and cohesion. The phenomenon of subsidence, suffusion, leading to the formation of caverns, the destruction of the walls of the well, which does not ensure the preservation of the wellbore in a stable state. In addition, tool and casing seizures occur, and the output and quality of the core are reduced.

The technical result that can be obtained by implementing the present invention is to increase the efficiency of drilling wells in permafrost due to the use of non-freezing at negative temperatures PGR, having:

- improved pseudoplastic properties, providing an increase in the holding and transporting abilities and the degree of cleaning of the walls of the well;

- reduced filtration as a result of the high speed of formation of a low permeable filter cake, preventing formation contamination and contributing to the conservation of its reservoir properties;

- reduced rate of thawing of permafrost, which prevents cavern formation and destruction of the walls of the well and, as a result, ensures long-term preservation of the wellbore in a stable state.

The technical result is achieved using a well-known polymer clay solution for drilling in permafrost, consisting of clay, a stabilizer in the form of a mixture of a polysaccharide reagent and a structurant, hydrocarbon antifreeze and water, which contains Acinetobacter Sp. Biopolymer as a polysaccharide reagent, and KSS in the following ratio of ingredients, wt.%:

Clay 6-8 KSSB 4-6 Acinetobacter Sp. Biopolymer 2-4 Hydrocarbon antifreeze 7-19 Water Rest

and the ratio of parts by weight Acinetobacter Sp. and KSSP is 1: 1-3, respectively. As a hydrocarbon antifreeze, it contains urea or glycerin.

The inventive composition meets the condition of "novelty."

Clay is used in the first or second grade with a flow rate of 57-97 kg / m ³ and a solution output of 17.5-10.8 m ³ / t, KSSB - according to TU 39-094-75, urea - according to GOST 2081-92, glycerin - according to GOST 6259-75.

The biopolymer Acinetobacter Sp. in the form of a culture fluid of the microorganism Acinetobacter Sp. under the name "Simusan" according to TU 64-13-127-88, under the name "Ritizan" according to TU 9291-001-58114197-2003. Their action in the PGR is equivalent.

Acinetobacter Sp. Biopolymer it is a viscous gel-like dispersed system of light cream color with a weak specific odor and pH in the range of 5-7, contains on average 1% (but not less than 0.5%) of exogenous high molecular weight (5-8 million units) polysaccharide, about 0.25% of biomass (producer's cellular substance), as well as monosugar, fatty acids, grape acid salt (pyruvate), the remainder of the salts, autolysate, formalin and water. The mass of dry residue is 2%.

The combined use of the ingredients used contributes to the production of PGR, which has a set of physicochemical and technological properties that increase the efficiency of drilling wells in permafrost. This is due to the following processes.

The rheological characteristics of most drilling fluids are significantly different from Bingham fluids, especially in the lower range of relative shear rates. To characterize the operation of the drilling fluid, the constants of the power law of the flow are most suitable, for example, the non-linearity index (pseudoplasticity) n, which characterizes the degree of deviation of the rheological properties of the fluid under consideration from Newtonian fluid. For Newtonian fluids, such as water, oil, glycerin, etc., n = 1. For pseudoplastic fluids, 0 <n <1, and the smaller n, the more fluid exhibits pseudoplastic properties. This means that the viscosity of such a fluid decreases with increasing relative shear rates and, conversely, the viscosity increases with decreasing relative shear rates. A decrease in the constant n allows one to improve the rock removal and well cleaning due to the leveling (flattening) of the fluid velocity profile in the annulus.

The parabolic distribution of velocities in the flow, characteristic of Newtonian fluids (n = 1), contributes to the formation of a swirling effect of suspended particles of drill cuttings and pushes them in the region with lower velocities. The result of this is the recycling of solid particles along the entire fluid stream and, as a consequence, low efficiency of well cleaning. A pseudoplastic fluid with a value of 0 <n <1 has a flatter velocity profile, which reduces the twisting effect, and hence the recirculation of the solid phase, and displaces it evenly up the wellbore. Lower values of n provide a flatter velocity profile and contribute to laminar flow and stability of the well.

The n values are calculated based on any two viscometer readings for two different rotor speeds according to the formula

where R ₁ - viscometer readings at N ₁ rpm;

R ₂ - viscometer readings at N ₂ rpm

(see Gray J.R., Darley G.S.G. Composition and properties of drilling agents (flushing fluids): transl. from English. - M .: Nedra, 1985. - P.190-193).

The component composition of the proposed PGR has low values of the nonlinearity index n (0 <n≤0.5), which, taking into account the above, indicates its high pseudoplastic properties. The pseudo-plasticity of PGR is due to the stabilizer used in the drilling fluid in the form of a mixture of Acinetobacter Sp. and KSSB.

Microorganisms Acinetobacter Sp. able to accumulate a polysaccharide in the culture fluid, which has significant advantages over the known biopolymers (xanthan, scleroglucan, etc.). Acinetobacter Sp. is a glucose-ethanol medium, which, unlike the carbohydrate raw materials of plant origin used in the production of xanthan, is characterized by a stable composition, lack of impurities, aseptic, low cost, simplicity and ease of transportation, storage and dosage. The biopolymer synthesized by Acinetobacter Sp. Combines the structural elements, chemical and rheological properties of xanthan and emulsan. On the one hand, it is a branched acid polysaccharide having the main chain as that of xanthan gum, on the other hand, it contains, like emulsan, residues of higher fatty acids, as a result of esterification of which it has a noticeable surface activity. This helps to improve the structural and rheological properties of the claimed PGR, the dispersed phase of which contains hydrated particles of clay minerals with a developed surface.

The presence of a large number of chemically active functional groups (hydroxyl, carboxyl, acetal, etc.) makes it possible to obtain various modifications of the biopolymer and form compositions based on it with other chemical compounds.

In this regard, the combined use of Acinetobacter Sp. with KSSB as a stabilizer is the main factor determining the increase in structural and rheological parameters of FGP (plastic viscosity, dynamic shear stress), which has a positive effect on its pseudoplastic properties, which contribute to the increase of holding and transporting abilities and the degree of cleaning of the well walls.

The manifestation of these properties is associated with the formation of complex macromolecular compounds - polymers of a three-dimensional structure from polysaccharides, biomass of the culture fluid and low molecular weight lignosulfonate fractions through the condensing action of polyvalent ions of the mineral background of the remainder of the nutrient medium containing CaCl ₂ , KH ₂ PO ₄ , MgSO ₄ , Fe ₂ (SO ₄ ) ₃ . At rest, the long chains of the resulting high molecular weight compounds are randomly oriented (entangled), since the electrostatic forces repulsively act between the molecules. When mixing the PGR, the chains tend to line up parallel to the direction of the flow, and this tendency increases with an increase in shear rate, which determines the laminar flow pattern of the circulation flow and stable well operation.

The formation of branched-chain macromolecular compounds from Acinetobacter Sp. and KSSB contributes to a better retention of water in a suspension of PGR and to a decrease in its filtration both by increasing the viscosity of the liquid phase as a result of the appearance of gel-like reaction products and by increasing the rate of formation of a low-permeability filter cake from PGR with the participation of urea or glycerol. For example, the formaldehyde contained in KSSB is capable of reacting with a urea to form a urea resin, and glycerol, as a triatomic alcohol, as a result of the esterification with lignosulfonic acids, KSSB forms polyesters of complex structure. At the same time, the free water content in the PGR decreases and its filtration ability is significantly reduced, which, in turn, prevents formation contamination and contributes to the conservation of its reservoir properties.

When drilling permafrost rocks, in which at least part of the moisture is in a solid state, measures should be taken to prevent thawing, since thawing of ice contained in the rock as separate inclusions can lead to a violation of the stability of the wellbore in the form of erosions and landslides with the formation of caverns . In order to prevent cavern formation and destruction of well walls during well drilling and to reduce the rate of thawing of permafrost, PGR contains ingredients that are hydrocarbon antifreezes - antifreeze additives, but which differ in physical and chemical effects on ice and frozen rock in general.

The rate of thawing of permafrost, characterized by the rate of ice destruction, decreases as a result of hydrophobization of its surface with Acinetobacter Sp. and KSSB, in which there is a decrease in the intensity of the surface interaction of ice and hydrocarbon antifreeze - urea or glycerin, which causes the destruction of ice even at low temperatures. In addition, a decrease in the rate of destruction of ice contributes to a higher clay content in the PGR. In this case, there is a decrease in the intensity of heat exchange processes, and, consequently, in the rate of ice melting.

When drilling and flushing a well with high structural and rheological properties (increased values of static shear stress), the flow occupies only a part of the annular section, forming a sedentary zone at the well walls. This zone protects frozen rocks from mechanical abrasive destruction and prevents the development of erosion (destruction) of ice and thawing of permafrost.

The achievement of the technical result from the application of the proposed PGR for drilling in permafrost rocks is due to the complex of its physicochemical, structural and rheological characteristics, realized due to the ingredient composition and their quantitative ratio, providing high pseudoplastic properties of the PGR, reduced filtration and the rate of thawing of permafrost, which the aggregate contributes to improving the efficiency of drilling wells in permafrost.

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

The content of clay in the amount of less than 6 wt.%, KSSB - less than 4 wt.%, Biopolymer Acinetobacter Sp. - less than 2 wt.%, and hydrocarbon antifreeze - less than 7 wt.% worsens the pseudoplastic properties (the pseudoplasticity index n increases), increases the filtration of the PGR and the rate of thawing, which does not ensure effective drilling of wells in permafrost.

The content of clay in the amount of more than 8 wt.%, KSSB - more than 6 wt.%, Biopolymer Acinetobacter Sp. - more than 4 wt.%, and hydrocarbon antifreeze - more than 19 wt.% is impractical, since there is no significant increase in the technological properties of PGR.

The content in the PGR of the stabilizer in the form of a mixture of Acinetobacter Sp. and KSSB with a ratio, parts by weight: Acinetobacter Sp. and KSSB less than 1: 1, respectively, increases the filtration and reduces the pseudo-plastic properties of the PGR (the pseudoplasticity index n increases), which leads to formation contamination, deterioration of the outflow ability of the PGR and well cleaning from cuttings.

The content in the PGR of the stabilizer in the form of a mixture of Acinetobacter Sp. and KSSB with a ratio of wt.h. Acinetobacter Sp. and KSSB more than 1: 3, respectively, is impractical, since there is no significant increase in the technological properties of PGR.

An analysis of the inventive step showed the following:

it is known that the powdered biopolymer product “Ritizan” is a thickener for flushing liquids (see Biostability of biopolymer solutions in the presence of bactericides / O. M. Scherbaeva, Yu. N. Moisa, E. Yu. Kambulov, V. A. Shavetov // Productivity recovery oil and gas wells: Sb.nauch.tr - Issue 10. - Krasnodar, NPO "Drilling", p.72);

Acinetobacter Sp. - "Simusan":

in the composition to increase oil recovery in order to increase the efficiency of the composition while simplifying preparation and reducing toxicity (see RF patent No. 2055982 of 08.20.1990, class E 21 B 43/22, published in OB No. 7, 1996 );

in the composition for oil recovery in order to increase the efficiency of oil recovery from waterlogged formations that are at a late stage of development (see RF patent No. 2122631 of 03.10.1996, class E 21 B 43/22, published in OB 33, 1998);

in the method of developing an oil field in order to increase the efficiency of the method by reducing the water permeability of the washed zones of the formation, improving the washing properties and increasing oil recovery (see RF patent No. 2136869 from 07/21/1998, class E 21 B 43/22, C 12 N 1 / 26, published in OB No. 25, 1999);

in the composition for waterflooding an oil reservoir in order to increase the efficiency of the composition for oil displacement by improving its viscosity properties (see RF patent No. 2140530 dated 05/05/1998, class E 21 B 43/22, C 12 P 19/04, publ. . in OB No. 30, 1999);

in the method of developing an oil field in order to increase the efficiency of the method by improving the rheological properties of the polymer in mineralized water and the formation of a microemulsion at the oil-solution interface (see RF patent No. 2132941 of 02.09.1997, class E 21 B 43/22, published in OB No. 19.1999);

in a method of displacing residual oil from a watered oil formation in order to increase the efficiency of a method of developing an oil field in conditions of heterogeneous permeability of formations at a late stage of their development by redistributing filtration flows, optimizing the gelation process, improving the water flooding process by using microbial synthesis products (see patent RF No. 2156354 dated 02.03.2000, class E 21 B 43/22, C 12 P 19/04, published in OB 26, 2000);

in a method for developing a water-oil deposit with the aim of increasing the efficiency of oil recovery, reducing water cut and lowering the cost of oil production by saving energy costs and reducing the metal consumption of equipment for oil production (see RF patent No. 2190092 of 03/27/2001, class E 21 B 43 / 22, published in OB No. 27, 2002);

in the method of isolating the influx of formation water in order to increase the efficiency of the method by increasing the size of the insulating screen (see AS SSSS No. 1726732 of 08.08.1989, class E 21 B 33/138, published in OB No. 14, 1992).

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 PGR meets the condition of "inventive step".

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

Example (fishing).

The vertical well of the Yamburgskoye oil and gas condensate field is being constructed to exploit the Cenomanian deposits. A Uralmash 3D-76 drilling rig is used with a typical drilling mud cleaning system.

Initial data

Conductor 324 mm Conductor descent depth 550 m Production tower 219 mm Depth of production casing 1400 m Cement Lift Height behind the conductor and production casing To the mouth

For drilling a Yamburgskoye oil and gas condensate field well under a conductor with a diameter of 324 mm, lowered to a depth of 550 m in the conditions of permafrost, the proposed surface drilling in the amount of 100 m ³ (65 m ³ +35 m ³ ), determined by the formula

V _PGR = V _SLE + V _cs ,

where V _well - the volume of the well minus the volume of the metal of the drill pipe, m ³ ;

V _cs - the volume of the circulation system, m ³ , is prepared at 10 m per cycle and pumped into the pump-tank unit.

For the preparation of 10 m ³ PGR in the following ratio of ingredients, wt.%:

Clay powder 6 KSSB four Acinetobacter Sp. Biopolymer 2 Antifreeze carbamide fifteen Water 73

with the ratio of parts by weight Acinetobacter Sp. and KSSB 1: 2, respectively, into the G2-10 clay mixer, filled with water in a volume of 7.87 m (73 wt.%), the calculated amounts of Acinetobacter Sp. (204 l of “Ritizan” with a density of 1060 kg / m ³ (2 wt.%) And 431 kg of KSSB (4 wt.%), Stirred for 1 h for the interaction of the ingredients and the formation of a homogeneous solution. Then add 647 kg of clay (6 wt. %), is stirred for 2 hours and left to swell for 1 day.After this time, 1617 kg of hydrocarbon antifreeze - urea (15 wt.%) are introduced and the suspension is stirred until homogeneous. The PGR, ready for use, is pumped into a pump -capacitive block.Thus, the entire volume of PGR is prepared for drilling a well under a conductor.

PGR has the following technological properties: ρ = 1078 kg / m ³ , Ф ₃₀ = 5 cm ³ , η = 14.22 mPa · s, τ ₀ = 111.9 dPa, θ _1/10 = 22/41 dPa, n = 0.39, _s.r.l. = 5.12 g / h, T _s = -9 ° C.

Conductor drilling in the IMF zone is carried out by the rotary method using the bottom of the drill string assembly: a bit with a diameter of 393.7 mm + UBT-203 50 m long + drill pipes TBPK-127x9 - the rest. Drilling is carried out at a mechanical speed of 18 m / h with a productivity of the UNB-600 mud pump equal to 0.045 m ³ / s, which, given the structural and rheological parameters of the PGR, provides a laminar flow regime in the annular space of the well.

In the process of drilling should be ensured that PGR cleaned from cuttings. For these purposes, it is advisable to use vibrating screens rather than hydrocyclones (sand and sludge separators), in which the structure of the Navy formed during the interaction of the biopolymer and KSSB can be destroyed, which will inevitably lead to a decrease in the pseudoplastic properties of the SGR (increase in the values of and), and therefore, to its deterioration holding and transporting abilities, as well as increased filtration. During drilling, PGR parameters are maintained at the level regulated by the introduction of additional amounts of biopolymer and KSSB culture fluid as necessary.

At the end of drilling the interval of 0-550 m under the conductor using conduction test, conduct operations to cement the conductor.

Further, drilling under the production casing to the design depth is carried out on the drilling fluid with the formulation prescribed by the project for well construction.

The use of PGR when drilling wells under conditions of permafrost with stable structural-rheological, pseudoplastic and filtration properties prevents the occurrence of complications associated with impaired wellbore stability.

Example 1 (laboratory)

To prepare 1000 g in 660 ml (66 wt.%) Water, 38 ml of Acinetobacter Sp. brand Ritizan (ρ = 1060 kg / m ³ ), which is (4 wt.%) and 40 g (4 wt.%) KSSB. The ratio of parts by weight Acinetobacter Sp. Ritizan and KSSB brands 1: 1 respectively. After stirring for 0.5 h, add 70 g (7 wt.%) Clay, mix for another 0.5 h and leave for 1 day to swell the clay. After 1 day, 190 g (19 wt.%) Of urea are introduced and stirred on a stirrer until it is completely dissolved and a homogeneous composition of PGR is obtained.

When drilling frozen rocks with high ice content, PGR, cooled to the required negative temperature, is used. In this case, the rate of ice destruction is minimal, because an almost complete cessation of thawing is observed.

When drilling non-icy frozen rocks at a positive temperature regime of the circulation of PGR (for example, at a temperature of 3-6 ° C), physico-mechanical and thermal erosion of frozen rocks occurs, accompanied by melting of the ice at a certain speed.

With this in mind, the positive temperature regime for exposure to PGR with an average temperature of 4 ° C, at which the main technological properties of the PGR was determined, was taken as the most severe for ice destruction.

The determination of the rheological parameters of the PGR is carried out on a Fann reoviscimeter. The rate of ice destruction in the PGR was determined by the loss of its mass per unit time.

PGR has the following properties: density ρ = 1112 kg / m ³ , filtration in 30 min Ф ₃₀ = 6.0 cm ³ , plastic viscosity η = 18.96 mPa · s, dynamic shear stress τ ₀ = 126.3 dPa, static shear stress for 1 and 10 min θ _1/10 = 22/35 dPa, pseudoplasticity index n = 0.19, ice destruction rate C _r.s. = 5.67 g / h, freezing temperature T _s = -12 ° C.

Example 2

Prepare 1000 g of PGR, g / wt.%:

Clay 60/6 Acinetobacter Sp.- Biopolymer 20/2 (use 19 ml, Ritizan ρ = 1060 kg / m ³ ) KSSB 40/4 Urea 150/15 Water 730/73

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1078 kg / m ³ , Ф ₃₀ = 5.0 cm ³ , η = 14.22 mPa · s, τ ₀ = 111.9 dPa, θ _1/10 = 22/41 dPa, n = 0.39, _{C. p.} = 5.12 g / h, T _s = -9 ° C.

Example 3

Prepare 1000 g of PGR, g / wt.%:

Clay
Acinetobacter Sp.- Biopolymer 80/8 Simusan 30/3 (use 28 ml, ρ = 1080 kg / m ³ ) KSSB 60/6 Urea 70/7 Water 760/76

and the ratio of wt. including biopolymer Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1090 kg / m, Ф ₃₀ = 3.5 cm, η = 22.38 mPa · s, τ ₀ = 86.1 dPa, θ _1/10 = 16/25 dPa, n = 0 , 46, S _R.L. = 4.27 g / h, T _s = - 5 ° C.

Example 4

Prepare 1000 g of PGR, g / wt.%:

Clay 60/6 Acinetobacter Sp.- Biopolymer Simusan 25 / 2.5 (use 23 ml, p = 1080 kg / m ³⁾ KSSB 50/5 Urea 100/10 Water 765 / 76.5

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1072 kg / m, Ф ₃₀ = 4.5 cm ³ , η = 14.22 mPa · s, τ ₀ = 94.7 dPa, θ _1/10 = 28/41 dPa, n = 0.36, _{C. p.} = 4.83 g / h, T _s = -7 ° C.

Example 5

Prepare 1000 g of PGR, g / wt.%:

Clay
Acinetobacter Sp.- Biopolymer 70/7 Ritizan 20/2 (use 19 ml, ρ = 1060 kg / m ³ KSSB 60/6 Urea 120/12 Water 730/73,

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 3, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1084 kg / m ³ , Ф ₃₀ = 6.0 cm ³ , η = 15.80 mPa · s, τ ₀ = 77.5 dPa, θ _1/10 = 22/32 dPa, n = 0.41, _{C. p.} = 4.87 g / h, T _s = -9 ° C.

Example 6

Prepare 1000 g of PGR, wt.%:

Clay 70/7 Acinetobacter Sp.- Biopolymer Ritizan 40/4 (use 38 ml, ρ = 1060 kg / m ³ ) KSSB 40/4 Glycerol 190/19 (use 148 ml, ρ = 1280 kg / m ³ ) Water 660/66

and the ratio of wt. including biopolymer Acinetobacter Sp. and KSSB is 1: 1, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1090 kg / m ³ , Ф ₃₀ = 3.5 cm ³ , η = 14.70 mPa · s, τ ₀ = 43.1 dPa, θ _1/10 = 44/54 dPa, n = 0.46, s _R.L. = 6.64 g / h, T _s = -7 ° C.

Example 7

Prepare 1000 g of PGR, g / wt.%:

Clay 60/6 Acinetobacter Sp .- "Ritizan" Biopolymer 20/2 (use 19 ml ρ = 1060 kg / m ³ ) KSSB 40/4 Glycerol 150/15 (use 117 ml ρ = 1280 kg / m ³ ) Water 730/73

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1084 kg / m ³ , Ф ₃₀ = 5.5 cm ³ , η = 14.22 mPa · s, τ ₀ = 66.0 dPa, θ _1/10 = 28/44 dPa, n = 0.36, _{C. p.} = 6.02 g / h, T _s = 5 ° C.

Example 8

Prepare 1000 g of PGR, g / wt.%: Clay 80/8 Acinetobacter Sp.- Biopolymer Simusan 30/3 (use 28 ml, ρ = 1080 kg / m ³ ) KSSB 60/6 Glycerol 70/7 (use 55 ml, ρ = 1280 kg / m ³ ) Water 760/76

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1066 kg / m ³ , Ф ₃₀ = 4.5 cm ³ , η = 12.64 mPa · s, τ ₀ = 31.6 dPa, θ _1/10 = 19/28 dPa, n = 0.38, _{C. p.} = 3.98 g / h, T _s = -3 ° C.

Example 9

Prepare 1000 g of PGR, g / wt.%:

Clay 60/6 Acinetobacter Sp.- Biopolymer 25 / 2.5 (use 23 ml, Simusan ρ = 1080 kg / m ³ ) KSSB 50/5 Glycerol 100/10 (use 78 ml, ρ = 1280 kg / m ³ ) Water 765 / 76.5 ,

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 2, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1076 kg / m, Ф ₃₀ = 3.5 cm ³ , η = 14.22 mPa · s, τ ₀ = 57.4 dPa, θ _1/10 = 35/57 dPa, n = 0.47, _s.r.l. = 5.11 g / h, T _s = -4 ° C.

Example 10

Prepared in 1000 g of PGR, g / wt.%:

Clay 70/7 Acinetobacter Sp.- Biopolymer Ritizan 20/2 (use 19 ml, ρ = 1060 kg / m ³ ) KSSB 60/6 Glycerol 120/12 (use 94 ml, ρ = 1280 kg / m ³ ) Water 730/73

and the ratio of parts by weight Acinetobacter Sp. and KSSB is 1: 3, respectively. Perform all operations, as in example 1.

PGR has the following properties: ρ = 1078 kg / m ³ , Ф ₃₀ = 4.5 cm ³ , η = 12.64 mPa · s, τ ₀ = 54.3 dPa, θ _1/10 = 32/47 dPa, n = 0.37, _{C. p.} = 5.37 g / h, T _s = -5 ° C.

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

Claims (2)

1. Polymer clay solution for drilling in permafrost rocks, consisting of clay, a stabilizer in the form of a mixture of a polysaccharide reagent and a structurant, hydrocarbon antifreeze and water, characterized in that it contains an Acinetobacter Sp. Biopolymer as a polysaccharide reagent and a structured biopolymer sulfite-alcohol barda KSSB in the following ratio of ingredients, wt.%: Clay 6-8 KSSB 4-6 Acinetobacter Sp. Biopolymer 2-4 Hydrocarbon antifreeze 7-19 Water Rest and the ratio of parts by weight Acinetobacter Sp. and KSSP is 1: 1-3, respectively. 2. The polymer clay solution according to claim 1, characterized in that it contains urea or glycerin as a hydrocarbon antifreeze.