RU2386787C2 - Construction method of deep well, plugging solution for its implementation and structure of deep well - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: there is implemented mudding of pit-bottom zone of well in the range of bedding of all permeable beds and interlayers up to producing formation before downlifting of casing string. Additionally mudding is implemented with usage of molecular fine-particle plugging solution. Fixation of casing pipes is implemented by plugging solution density of stone of which is equal to 1.0-1.1 of average density of formations, opened by well. In structure of deep well the letter technical and production strings are equipped by fragments-insertions of specified length, allowing enough strength characteristics for operation of well, but easily destroyed by known methods. Proposed technology provides increasing of quality of fixation of casing strings and to prevent interstratal overflows.

EFFECT: increased range of application of plugging solution and increased operation time of plugging stone, included into structure of the well fragments of insertion provide ability of direct contact of plugging material with rock.

5 cl, 2 dwg

Description

The invention relates to the oil and gas industry, in particular to the construction of structural exploration, exploration, production and injection wells. It is recommended for use in the construction of water and other wells.

There is a method of reducing the permeability of formations during the construction of a well structure by treating the walls of the well during drilling with mud (Kurochkin BM et al. "Intensification of the process of colmatization of fine-porous permeable rocks by mechanical means." Oil industry, 1973, No. 6, p. 11 -fourteen).

The disadvantages of this method are:

- the need for multiple removal of the clay crust to ensure effective reservoir formation;

- a small depth of penetration of clay particles into the reservoir;

- the lack of effect with depression on the reservoir, the asymmetric position of the tool, the presence of caverns and in the absence of clay cake on the walls of the well;

- short duration of the mudding effect due to erosion of the clay crust by the formation water and its destruction by formation fluids with a decrease in pressure in the wellbore below the formation.

Known colmatation when attaching a wellbore according to patent RU No. 2208129, including drilling an interval of attachment with the supply of jet jets of drilling fluid with hardening material, for example cement, onto the walls of the well, lowering and cementing the casing, in which cement is introduced into the drilling fluid before opening the permeable formations in this case, in the near-barrel zone and on the walls of the borehole, a mud layer with a concentration of the solid phase of cement particles up to 75-90% for their hardening and image of cement waterproofing screen with a thickness of 15-30 mm.

The main disadvantage of this method is the absence of the effect of colmatation of the borehole zone due to poor filterability of cement in permeable formations up to its absence, especially in finely porous and finely fractured formations. This is due to the particle size of clinker known cements, the bulk of which exceeds the pore size of permeable rocks.

A known method of constructing a construction of a deep well (EM Solovyov “Pumping a well.” - M .: Nedra, 1979, pp. 90-101), including drilling rocks, lowering casing and production strings and filling the annulus with grouting, in which the telescopic design of the well consists of steel pipes of various diameters and annular and annular spaces, sealed with a cement-based binder (prototype).

This method has the following disadvantages:

- in the near-borehole zone of the well already in the process of construction (drilling, cementing) there are inter-reservoir flows (MPF) of deep fluids (gases, liquid hydrocarbons, formation water and brines), which cause intercolumn pressures (MKD), disturbance of the underground balance, loss of the industrial part of the natural minerals, the formation of man-made deposits, griffins and other negative impacts on the subsoil and the environment, the elimination of which requires a lot of time and money;

- the inability to use cementing columns and sealing the annular space of cement slurries whose stone density is equal to or greater than the average density of rocks, open holes, associated with their absorption in the intervals of permeable rocks due to the difference between the pressure created by the cement slurry and reservoir-pore pressures. Grouting mortars with a density of ≤1.0-1.9 g / cm ^{3 are} usually used, although the density of most rocks composing the sedimentary cover of oil and gas fields varies from 1.86 g / cm ³ to 2.6 or more and on average is about 2.35 g / cm ³ . This does not allow the creation of the necessary counterpressure, similar to mountain pressure, to the fluid developing formations, especially with an abnormally high reservoir pressure (AAP), which is disturbed during drilling, which leads to the formation of deep fluid filtration paths in the cement ring (casing - rock) already at the stage formation of cement stone. In the future, in the process of inevitable aging and destruction of cement stone, MPP can take on alarming proportions.

- the complexity of the drilling process, associated with an increased likelihood of a collapse of the wellbore and sticking the drill string with the tool;

- low quality of fastening of casing strings and sealing annular space, due to the possibility of hydraulic fracturing, absorption of the technological solution by permeable rocks and incomplete replacement of the drilling fluid by grouting during the process of selling;

- high costs for well overhaul (KRS) and its liquidation.

The technical result in terms of the method of constructing a deep well is to restore the tightness of the lining of the well, to prevent inter-reservoir flows during the construction, operation and after liquidation of the well.

The technical result is achieved by the fact that in the method of constructing a deep well, including drilling rocks, lowering casing and production strings, filling the annulus with cement slurry, prior to lowering the casing stems, the borehole is clogged in the intervals of reservoir layers that lie open in the open section to the productive layer. When opening homogeneous reservoir rocks with a thickness of more than 30-50 m in the section of the well, as well as with different permeability and pore pressure of the formations or occurrence of reservoirs from each other at a considerable distance, more than 10-20 m, mudding is carried out intervalically under pressure by known methods.

A well-known design of a deep well by the method of constructing a design of a deep well (E.M. Soloviev. Well injection. - M .: Nedra, 1979, pp. 90-101). The design of a deep well comprises casing and production casing and a packer in the production casing.

This design has several disadvantages. The presence of a fixed packer, which is part of the layout of underground equipment, which must then be drilled during the overhaul of wells, especially exploiting deposits containing aggressive components of H ₂ S and CO ₂ . During well abandonment, this is due to the need over the reservoir and the obvious sources of MPP (secondary deposits, rape lenses with AVPD, etc.) to create technological (10-30 m or more) windows in the production and casing strings in the interval of occurrence of rocks - tires with the complete destruction of their bodies to ensure direct contact of the grouting material with the rock, while restoring the fluid-resistant properties of the natural tightness of the rock, broken during drilling. Costs increase when using casing strings made from alloy steel of increased strength N-80, HS-90 ÷ 95, NT-90SS and higher.

The technical result in terms of design is to enable direct contact of the grouting material with the rock and the use of quick-release packer.

This technical result is achieved by the fact that in the design of a deep well, including casing and production strings, the last technical and production strings include fragments - inserts, for example, cylindrical, 20-50 m long of easily destroyed material by known methods in at least one two intervals, opposite the fluid-resistant rocks-tires, lying above and in the immediate vicinity of the working reservoir and / or the overlying saturated reservoir-source MPP, while m production casing includes a saddle under the quick-release packer.

Known cement mixture according to ed. USSR No. 692982 for isolation of absorbing formations, containing a binder, an aqueous solution of calcium chloride and a polymer additive, in which, in order to obtain a tamping mixture having high curing strength in conditions of intense water overflow, it contains gypsum-clay cement as a binder, and as polymer additives - waterproofing polyacrylonitrile (gipan) in the following ratio of components, wt.%:

Gypsum-alumina cement - 41-51

Gipan - 38-23

Calcium Chloride Aqueous Solution

(density 1.06-1.10 g / cm ³ ).

This mixture has the following disadvantages:

- limited scope, since the resulting cement stone can exist only in aqueous media (formation water), where the content of ions of polyvalent materials Ca ⁺⁺ , Mg ⁺⁺ , Al ⁺⁺⁺ , Fe ⁺⁺⁺ , etc. not less than 8-9 g / l, which is extremely rare in natural conditions;

- the short life of the cement stone (from 3 to 12 months) in fresh, weakly mineralized waters and sodium chloride brines, since, firstly, the polymer coagulate is rapidly dissolved, and secondly, the cement binder is destroyed due to salt aggression ;

- poor filterability (penetration) up to the absence of finely porous and finely fractured formations (<10-15 microns) due to coarse grinding of cement clinter, the size of most of which exceeds 15-30 microns.

Known grouting according to ed. USSR No. 1559115 for insulation of absorbing formations, including calcium chloride and water, in which to increase the quality of insulation by increasing the stability of cement stone to erosion by washing liquids, it additionally contains water-soluble metal sulfate in the following ratio, wt.%:

Calcium Chloride - 52.4-61.5

Water-soluble metal sulfate - 0.2-4.4

Water is the rest.

This grouting mortar has the following disadvantages:

- limited scope, since at temperatures above 10 ° C, which is typical for the vast majority of reservoir layers, the formed crystalline hydrates dissolve;

- short life of crystalline hydrates even at a temperature of 8-9 ° C, since during the mixing of calcium chloride with metal sulfates, a small amount of up to 4.0% poorly soluble calcium sulfate and well soluble metal chlorides are formed. Upon contact with fresh and weakly mineralized waters, the formed crystalline hydrates rapidly dissolve.

Closest to the claimed invention for grouting compositions is RU Patent No. 2299230, in which grouting mortar for isolating a productive formation covered by casing strings includes Microdur-261R-X and water and additionally contains calcium chloride, aluminum sulfate, nitrilotrimethylene phosphonic acid - NTP at the following ratio of components, wt.%:

Microdur 261R-X-10-30

Calcium Chloride - 20-50

Aluminum sulfate - 0.5-3.0

NTF - 0.0-0.2

Water is the rest.

The disadvantage of this grouting mortar is the short lifespan of its stone in fresh and weakly mineralized formation waters, due to the large (up to 50 wt.%) Content in its composition of the readily soluble salt of calcium chloride (CaCl ₂ ).

The technical result of the invention in terms of grouting compositions for mudding the borehole zone of the well is to prevent inter-reservoir flows during the construction, operation and after liquidation of the well, achieving equilibrium of the annular space-rock system and the long-term mudding effect. This technical result is achieved in that the radius of the collatable borehole zone is taken to be 1.1-1.5 (radius) of the distance from the wellbore at which macro and microcracks can form in the rock, the borehole colmatation in the intervals of reservoir layers is carried out molecularly fine-dispersed curing grouting mortar of the following composition, wt.%:

Calcium Chloride (CaCl) - 10-20

Sodium sulfate (Na ₂ SO ₃ ) - 11.46-22.92

Plasticizer (C-3) - 0.2-0.5

Fine binder with particle sizes less than 6 microns - 15.0-30.0

Water is the rest.

In this case, annular space is filled with grouting mortar, the density of the stone of which is equal to 1.0-1.1 of the average density of rocks exposed by the well.

The essence of the invention lies in the fact that the colmatization of the borehole zone is carried out in the intervals of all permeable formations and interlayers to the producing formation before the casing strings are lowered. If there are homogeneous rocks in the open interval - reservoirs with a thickness of more than 30-50 m, at different permeability and pore pressure of the reservoirs or reservoirs occurring at a considerable distance, more than 10-20 m, interval-like colmatation by known methods using known hydrodynamic, wave , acoustic, electrophysical and other devices and packers. Selling cement slurry into the formation is carried out at a pressure of not more than 0.8 of the hydraulic fracturing. Colmatization in the occurrence intervals of all permeable formations and interlayers of the borehole zone is carried out using a molecularly-fine grouting mortar, in which the particle size of the binder is less than 6 microns. Fastening of casing strings is carried out with cement slurry, the density of the stone of which is equal to 1.0-1.1 of the average density of rocks exposed by the well. In the construction of a deep well, fixed by the proposed method during its construction, the last casing technical and production casing is equipped with fragments of inserts, for example cylindrical, of a given length, having sufficient strength characteristics for well operation, but easily destroyed by known methods. The casing layout includes a saddle for a quick-release packer.

Figure 1 shows the design of a deep well of the prototype.

Figure 2 presents the design of a deep well according to the invention.

The design of a deep well includes: casing strings (direction, conductor, technical) 1; production casing 2; Possibly percolated zones of permeable formations 3; plugged annular spaces 4, including intervals opposite the reservoir 5, the apparent sources of the MPP 6 and 8 and the rocks-tires 7; insert fragments 9, for example, cylindrical, and a saddle under the quick-release packer 10.

A method of constructing a deep well structure according to the invention is carried out as follows (see figure 1, 2).

Known methods, rotary or using turbodrills or downhole motors, conduct rock drilling according to the project for the construction of wells. Before the descent of each casing string 1, 2, a well-known complex of geophysical well surveys (GIS) is carried out, on the basis of which all potentially permeable formations and interlayers in the rock are identified. Then, using a molecularly-fine grouting mortar of the proposed composition, in the occurrence intervals of all permeable formations and interlayers, the borehole zone 3 is clogged by known methods, including injection into the formation under pressure. Selling cement slurry into the formation is carried out at a pressure of not more than 0.8 of the hydraulic fracturing. The volume of grouting mortar is taken from the need to overlap the zone of development of macro- and microcracks that arise due to vibromechanical stresses during drilling at a distance of up to 3-5 well radii, which then serve as filtration paths for reservoir fluids (gas, oil, water).

The required volume of mudding cement slurry is determined by the well-known formula:

where V _tr - the volume of mudding cement slurry, m ³ ;

π = 3.14;

R is the radius of the borehole zone of the well to be muddled, m;

r is the radius of the wellbore;

N _eff - effective collector power in the interval of work, m;

k _p - coefficient of open porosity of the reservoir.

In this case, the radius of the collimated borehole zone is taken to be 1.1-1.5 (radius) of the distance from the wellbore, at which macro- and microcracks can form in the rock. With a value of less than 1.1, incomplete overlapping of the movement paths of formation fluids is possible, and with more than 1.5, the flow of grouting mortar and production costs unnecessarily increase.

In the section of the sedimentary cover of most hydrocarbon deposits, reservoirs (saturated with reservoir fluids) are found - reservoirs that have different gradients of pore reservoir pressure, from abnormally low (ANPD) to abnormally high (AVP).

Simultaneous colmatation of different formations is possible provided that their pore pressure gradients are equal or if their differences are insignificant. The joint formation of seams with different gradients can lead to the fact that the MTDR is completely squeezed into the formations with less pressure and does not fall into the near-bore zone of the formations with increased pressure. An increase in the wellhead pressure of the well for collapse of a formation with a higher pressure can lead to hydraulic fracturing of formations with a lower pressure.

Therefore, when opening homogeneous rocks in the section, reservoirs with a thickness of more than 30-50 m, as well as with different permeability and pore pressure of the reservoirs or occurrence of reservoirs from each other at a considerable distance, more than 10-20 m, interval permeation of permeable rocks is carried out using known hydrodynamic , wave, acoustic, electrophysical and other devices and packers.

For colmatization of the borehole zone of the well, a molecular-fine grouting slurry (MTDTR) of the following composition is proposed, wt.%:

1. Calcium chloride (CaCl ₂ ) - 10-20

2. Sodium sulfite (Na ₂ SO ₃ ) - 11.46-22.92

3. Plasticizer (C-3) - 0.2-0.5

4. Fine binder with particle sizes <6 microns - 15.0-30.0

5. Water - the rest.

The ratio of Na ₂ SO ₃ to CaCl _{2 is} taken to be 1.146 according to stoichiometry. The resulting solutions have a rheology close to water, with a nominal viscosity of 16-18 seconds, good permeability in core samples of low permeability rocks and mechanical properties sufficient for colmatant. The stones of these solutions have high fluid-resistant characteristics, see table 1.

When mixing the components later in the reaction: CaCl ₂ + Na ₂ SO ₃ = CaSO ₃ ↓ + 2NaCl

a sediment insoluble in fresh and weakly mineralized formation waters is formed - calcium sulfite, which, unlike the prototype, increases the life of cement stone in reservoir conditions for a long period of time, including construction, operation and liquidation of the well. The presence of sodium chloride (NaCl) in the composition of the stone during the reaction allows the proposed MTDTR to be used to clog aquifers with high salinity and rape-bearing chlorosodium sulfate-terrigenous interlayers. When the content of calcium chloride in the solution is less than 10% and sodium sulfite is less than 11.46%, the solution becomes unsaturated with sodium chloride, which leads to a decrease in stone resistance in highly mineralized formation waters. With an increase of more than 20% and 22.92%, respectively, its strength characteristics sharply decrease. The content of plasticizer C-3 is less than 0.2 wt.% Leads to an increase in the viscosity of the solution and a reduction in the time of thickening and setting, with more than 0.5%, the resistance of the stone in various environments decreases.

In the cement slurry, as a finely dispersed binder, for example, Microdur 261R-X can be used.

The specified "Microdur 261R-X" is a particularly finely dispersed mineral binder with a guaranteed smooth change in particle size distribution. "Microdur 261R-X" is produced by air separation of dust when grinding cement clinker. The manufacturing technology of the OTDV “Mikrodur 261R-X” was developed and mastered by the specialists of the INTRA-BAVGmbH company together with the specialists of the Dyckerhoff concern (Wiesbaden, Germany) and is protected by a European patent.

The diameter of the grains "Microdur 261R-X" is 6-10 times smaller than the particles of the cement clinker itself. Due to the small size (grain diameter <6 μm) of the particles and the smoothly selected particle size distribution, the Microdur 261R-X suspension has a fluidity comparable to that of water, even with a minimum W / C. The expiration time (conditional viscosity) of a suspension under the age of 1 hour ranges from 16 to 17 seconds and provides high penetration into loess soils, dense concrete and rock. Mikrodur 261R-X is a powder with a specially selected mineral and particle size distribution. This provides a high water holding capacity (W / C up to 6.0) and rheological characteristics commensurate with the rheology of ordinary water. "Microdur 261R-X" is resistant to chemical influences, including the effects of sulfates, hydrogen sulfide and chlorine. Thus, it can be considered as an alternative to liquid glass and polymer compositions (epoxy, carbide, phenol formaldehyde, etc.) with the following advantages: durability, simple and convenient technology for preparing a suspension and injection, environmental cleanliness, uniformity with conventional cements in composition, compatibility with cement and rock, the ability to perform work in conditions of flooded and water-saturated structures and formations.

When the content of a finely dispersed binder in the grouting composition, for example, Mikrodura 261R-X, is less than 15 wt.%, The strength characteristics of the stone decrease, with an increase of more than 30% the solution becomes highly viscous (non-pumpable).

After the colmatation of the borehole zone of the open borehole design interval, the casing is run. Then, it is fastened and sealed (annular) of the space between the column and rock with grouting compositions 4, the density of the stone of which is equal to 1.0-1.1 of the average density of rocks opened by the borehole in the interval of lowering the casing string. When the density of the cement slurry is less than 1.0 of the average density of the rocks, backpressure on the reservoirs, similar to the rock pressure, is not achieved, and with a density of more than 1.1, hydraulic fracturing of the layers can occur during the squeezing operations. The use of cement slurries with a density of 1.0-1.1 average rock density is necessary to restore equilibrium in the annular space - rock system, which is disturbed during drilling, which, unlike the prototype, impedes the movement of reservoir fluids through annular space. The density of most rocks composing the sedimentary cover of oil and gas deposits varies from 1.86 g / cm ³ to 2.6 or more and averages about 2.35 g / cm ³ .

Table 1.
Sample Test Results No. p / p The recipe, wt.% The solution parameters γ - g / cm ³
D - cm
B - viscosity, s
KPR - permeability, 10 ^-15 m ² when Ro-764 mm Hg Rysl.-3.0 tech. t = 25 ° C Thickening, h-min The beginning hr, end of hr., h-min Compressive strength, kg / cm t = 75 ° C, P = atm. Exposure 5 days., T = 75 ° C, P = atm. Months Exposure at t = 22 ° C, P = atm. 1 month 3 months 6 months 12 months in fresh water in NaCl brine formation water + H ₂ S one. CaCl ₂ - 17.17 2-00 3-40 23.1 1 month 22.27 20.15 18.97 Na ₂ SO ₃ - 19.6 γ = 1.46 S-3 - 0.23 D> 25 4-30 3 months 27.32 24.85 18.55 Microdur - 18.0 B = 17.5 6 months 21.55 21.55 19.90 Water - 45.0 CRP≤0.001 12 months 22.00 21.80 19.00 2. CaCl ₂ - 13.61 2-25 2-45 26.3 1 month 19.80 21.45 24.75 Na ₂ SO ₃ - 15.37 γ = 1,495 S-3 - 0.24 D> 25 3-15 3 months 19.80 28.05 22.28 Microdur - 23.59 B = 16.1 6 months 19.50 20.62 23.15 Water-47.19 CRP≤0.001 12 months 19.50 23.00 22.50 3. CaCl ₂ - 12.49 2-15 2-35 36.1 1 month 30.52 39.60 38.77 Na ₂ SO ₃ - 14.23 γ = 1.44 S-3 - 0.28 D> 25 2-50 3 months 30.50 37.95 37.95 Microdur - 26.2 B = 17.5 6 months 30.22 33.82 38.00 Water - 46.8 CRP≤0.001 12 months 30.51 38.30 38,20

Thus, the present invention provides for the colmatation of all formations - reservoirs, lying in the open section of the well to the production reservoir.

Colmatization of the peri-bore zone in all permeable formations and interlayers lying above the production reservoir allows:

- prevent inter-reservoir flows of deep fluids (gases, liquid hydrocarbons, formation water and brines) in the near-hole zone for a long period of time, including the construction, operation and liquidation of the well; this, in turn, minimizes the negative impact on the underground balance and the environment;

- strengthen the rock framework and thereby the wellbore; at the same time, the probability of collapse of the barrel, sticking of the drill string and tool is sharply reduced, the likelihood of hydraulic fracturing is reduced;

- prevent the absorption of drilling and grouting mortars during the fastening and sealing of the well structure; flushing and replacement of the drilling fluid with grouting occurs more fully, cement adhesion to casing metal and rock improves, cementing quality improves;

- use cement slurries for cementing columns and sealing annular space, the density of the stone of which is equal to or greater than the average density of rocks exposed by the well.

This provides the necessary counterpressure, similar to that of the mountain, to the fluid-developing strata, especially with high pressure flow disturbance, which is disturbed during drilling, and the equilibrium of the annular space-rock system is achieved.

According to the invention, the well’s design provides for a productive horizon 5 and / or explicit sources of MPP 6.8 in the interval of occurrence of cover rocks 7, include fragment inserts 9, for example, cylindrical, of a given length in the layout of the last technical and production columns (20-50 m) from pipes with sufficient strength characteristics for well operation, but easily destructible by known methods (mechanical, chemical, electrochemical, etc.). As a material for fragments - inserts, you can use, for example, known aluminum alloys or fiberglass. So, aluminum alloys dissolve quite easily in acids and during electrochemical exposure, and fiberglass without major difficulties can be removed mechanically.

When the length of the inserts 9 is less than 20 m, they may not coincide in depth due to the lack of access of one of the columns, and it is impractical to use inserts longer than 50 m, since the height of a reliable fluid-resistant coating depending on the reservoir pressure of the MPP source is determined within 10-30 m .

The inclusion in the layout of the last technical 1 and production casing 2 fragments-inserts 9, for example cylindrical, during the liquidation of a well that has fulfilled its purpose, it is possible to reliably isolate the productive horizon, the relevance of which increases when aggressive components CO ₂ and H ₂ S are present in it, and prevent flow of reservoir fluids from it to overlying horizons. In this case, sharply compared with the prototype, the time and money spent on creating technological windows in production and technical columns with the complete destruction of their bodies to ensure direct contact of the grouting material with the rock while creating a fluid-resistant screen to restore the natural integrity of the rock-cover, broken in the process drilling.

According to the invention, in contrast to the prototype, a landing saddle 10 under a quick-release packer is included in the layout of the production casing.

The inclusion in the layout of the production casing of the landing saddle 10 can drastically reduce the cost of well repair (KRS) for drilling and removing fixed packers, which are necessarily part of the underground equipment in fields with high pressure and containing aggressive components CO ₂ and H ₂ S.

Example:

Design design of a production well:

Elongated direction D = 630 mm - 50 m - the shoe is located in clay deposits.

Conductor D = 426 mm - 298 m - the shoe is located in the clays of the Akchagyl tier.

I intermediate technical column D = 324 mm - 1646 m - the shoe is located in the roof of the salts of the Kungur tier.

II technical column D = 244.5 mm - 3850 m - the shoe is located in dense fluid-resistant Sakmar-Artinsky deposits, represented by clay limestones and anhydrites.

Production casing D = 177.8 mm - 4150 m - the lower part of which (3900-4150 m) is located in the productive horizon of the Bashkir layer.

An open section of sedimentary rocks is represented by deposits of Permian, Triassic, Jurassic, Cretaceous, Neogene and Quaternary.

After drilling the wellbore for an elongated direction, before its launch, permeable sand with an open porosity of 25% and a total effective power of 21 m of the proposed MTDTR with a nominal viscosity of 17 seconds and a specific gravity of 1.45 g / cm ^{3 were} obtained according to well log data.

Calculation of the MTDTR volume was carried out on the condition that the radius (R) of the clogged borehole zone was 1.5 times greater than 3 radii of the open wellbore equal to 690 mm, which amounted to 30.25 m ³ . Selling of the solution was carried out through drill pipes in a known manner at an excess pressure at the pump unit of 0.15 MPa. After washing, the well was left in the OZZ for 24 hours. After 24 hours, the tightness of the insulation of permeable formations was determined by reducing the level to the bottom, by blowing technical nitrogen. The influx of reservoir fluid (water) is not marked. The average radius of the zone of mudding of permeable sands was 1.55 m.

After the descent of the elongated direction, its cementing was carried out with a cement composition with a density of 1.89 g / cm ³ equal to the average rock density in the range 0-50 m.

Drilling under the conductor D = 426 mm in the interval of 50-300 m was carried out by the rotary method on the drilling fluid, the average radius of the open hole in this case was 0.235 m. According to well log data, 6 reservoirs with a total thickness of 87 m, represented by sandstones with average porosity of 22%. The required volume of the MTDTR, calculated on the condition that the radius of the zone of mudding is 1.4 times greater than the 3 radii of the open trunk, was 43.50 m ³ .

Alternate colmatation of the selected reservoirs was carried out from the bottom up using 2 hydraulic packers with the sale of cement slurry at an overpressure of 1.5 ÷ 2.0 MPa, which is less than 0.8 of the hydraulic fracturing. After the squeezing and flushing operations, the well was left in the OZC at a pressure of 1.0 MPa. After 24 hours, we worked with a chisel to the wellbore, replaced the drilling fluid with water, and determined the effectiveness of the mud work by lowering the water level by 250 m from the mouth. That is, they created a depression on the strata along the wellbore from 0.6 MPa in the upper reservoirs to 2.2 MPa in the lower ones. We conducted a water level monitoring for 8 hours - there is no inflow, the dumped areas are tight. The average depth of bedding was 0.99 m.

The conductor was cemented in a known manner, with a cement slurry of 2.1 g / cm ³ , which amounted to 1.05 average rock density in the range of 50-300 m

Drilling for the first technical string D = 324 mm, in the interval 300-1650 m, was carried out by the rotary method on a drilling fluid with a density of 1.15-1.20 g / cm ³ , while the average radius of the open hole was 0.190 m. In the open interval, 35 reservoir layers are represented, represented by sandstones, siltstones and limestones with porosities from 13 to 18% with a total effective capacity of 280 m. The volume of the MTDTR was calculated objectively, for 2-3 layers with similar FES values and located close to each other, provided that the radius of the colma zone It is 1.3 times more than 4 well radii and is equal to 0.99 m. The total required volume of MTDTR was 97.5 m ³ . Colmatization of the borehole zone in the identified reservoir formations was carried out objectively with the sale of a curable grouting mortar under an excess pressure of 3.0 to 12.0 MPa, which is less than 0.8 fracturing pressure. After the OZZ, the study of the trunk and the tightness test, 324 mm of the technical string were lowered to a depth of 1646 m. Then, using the known direct cementing method, they were fastened and sealed in the annular space (the column is rock) and the annular (between 324 mm and 426 mm casing) spaces with cement slurry with a density of 2.25 g / cm ³ , with an average rock density of 2.25 g / cm ³ .

Drilling under the second technical string in the range of 1650-3855 m was carried out using bits TSh-295 mm using the rotary method. Two 10-meter rape-bearing sulfate-terrigenous strata with a coefficient of AHP = 1.9 were discovered in the saline sediments of the Kungurian stage, and a Philippov horizon with a AHP = 1.7, represented by sulfate-carbonate rocks, with an effective thickness of 5 m, was discovered below.

The colmatation of open collectors was carried out separately. Considering the AVPD in the collectors, the radius of the mud zone was assumed to be 1.5 of the 5 radii of the open trunk, which was 0.4 m for the rape intervals, and 0.12 m for the Filipov intervals. The calculated radius of the mud zone was 3.0 m and 1 , 13 m respectively. The required volume for raponiferous strata was 46.5 m ³ , for the Filipov reservoir - 1.04 m ³ . After completion of the colmatation works and leak testing with depression on the strata to 10.0 MPa, a 244.5 mm technical column was lowered to a depth of 3850 m and cemented with grouting composition with a density equal to the average rock density of 2.35 g / cm ³ .

Before launching 2 technical columns, two fragments-inserts of 30 m length from special aluminum alloys were included in its composition. One is higher than 100 m in the Philippine horizon in the interval 3700-3670 m, the second is 100 m higher than the upper rape-bearing layer in the interval 3340-3310 m

Drilling subsalt deposits at 177.8 mm production casing to a depth of 4155 m was carried out with bits TSh-215.9 mm. It also included two insert fragments 30 m long with a calculation of their location after descent in the intervals of 3700-3670 m and 3340-3310 m. In addition, at a depth of 3830 m, the production casing was equipped with a special landing seat for a quick-release packer. After its descent, it was cemented in a known manner in two stages, with a cement composition of a specific gravity of 2.35 g / cm ³ .

About 218 m ³ MTDTR were required for the colmatization of the perineal zone in all the permeable formations and interlayers of the open borehole, which lie above the operational productive layer of the Bashkir layer.

After testing the tightness of the entire structure of the well in a known manner, a highly sensitive complex of acoustic logging (GAB) was carried out, which showed the absence of casing MPPs, while there was no MCD at the wellhead.

Using the invention provides the following advantages:

- allows you to prevent inter-reservoir flows of deep fluids (gases, liquid hydrocarbons, formation water and brines) in the near-hole zone for a long period of time, including the construction, operation and liquidation of the well;

This in turn minimizes the negative impact on the underground balance and the environment.

- the rock framework is strengthened and thus the wellbore;

At the same time, the likelihood of a collapse of the barrel, sticking of the drill string and tool is sharply reduced, and the likelihood of hydraulic fracturing is reduced.

- allows you to prevent the absorption of drilling and grouting mortars in the process of fixing and sealing the structure of the well;

The most complete flushing and replacement of the drilling fluid with grouting, cement adhesion to casing metal and rock is improved, and the quality of grouting is improved.

- allows you to use cement slabs for fixing columns and sealing annular space, the density of the stone of which is equal to or greater than the average density of rocks uncovered borehole;

This provides the necessary counterpressure similar to that of the mountain on the fluid-developing strata, especially with high pressure flow disturbance, which is disturbed during the drilling process, and equilibrium of the annular space-rock system is achieved, which prevents the formation fluids from moving through annular space.

- reduced the time and cost of cattle and its elimination.

The expected economic effect of using the proposed invention, depending on the depth of the well, will be from 10 to 20 million rubles.

Claims (5)

1. A method of constructing a deep well structure, including drilling rocks, lowering casing and production strings, filling the annulus with grouting cement, characterized in that prior to lowering the casing stems, the borehole is milled in all intervals of the reservoirs, which are in open section up to productive formation, while filling the annular space is carried out with cement slurry, the density of the stone of which is equal to 1.0-1.1 of the average density of rocks, sun rytyh borehole. 2. The method according to claim 1, characterized in that the radius of the collimated borehole zone is taken to be 1.1-1.5 (radius) of the distance from the trunk, at which macro and micro cracks can form in the rock. 3. The method according to claim 1 or 2, characterized in that when opening homogeneous rocks - reservoirs with a thickness of more than 30-50 m, at different permeability and pore pressure of the formations, or when the reservoirs occur at a considerable distance of more than 10-20 m colmatization is performed intervally under pressure by known methods. 4. Grouting mortar for implementing the method according to any one of claims 1 to 3, containing a finely dispersed binder, calcium chloride and water, characterized in that sodium sulfate, a plasticizer (C-3) are introduced into the composition in the following ratio, wt.%:
calcium chloride (CaCl ₂ ) 10-20 sodium sulfate (Na ₂ SO ₃ ) 11.46-22.92 plasticizer (C-3) 0.2-0.5
fine binder with dimensions
particles less than 6 microns 15.0-30.0 water rest 5. The design of a deep well for implementing the method according to any one of claims 1 to 3, containing casing and production strings, characterized in that the last casing technical and production strings are equipped with fragments - inserts 20-50 m long, with sufficient strength characteristics for well operation , but easily destructible by known methods, in at least one, two intervals opposite fluid-resistant rocks - tires lying above and in the immediate vicinity of the working reservoir and / or the overlying fluid-saturated formation - an obvious source of MPP (inter-reservoir flows), while the production casing includes a landing seat for a removable packer.

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