RU2149973C1 - Method of drilling the directional and horizontal prospecting or producing well from oil and gas - Google Patents

Abstract

FIELD: drilling of directional and horizontal wells. SUBSTANCE: essence of invention consists in that on sections of trajectory of formation and stage casing of directional and horizontal wellbores, created and maintained in wellbore are conditions of partial or full weightlessness of pipe string by regulation of reduced density of pipe string components and holding drill hydrosphere circulating in well. EFFECT: higher efficiency of drilling of directional and horizontal branches from main wellbore. 2 cl, 7 dwg

Description

The invention relates to the drilling of directional and horizontal wells with large waste of trunks from the vertical for the development of oil and gas reserves in environmental areas and water areas, as well as many “small” ones (with reserves of categories A + B + C _{1 of} less than 10 million tons ) satellite fields, the development and construction of which, when using traditional technical means of drilling and well completion, in many cases are unprofitable.

 A known method of drilling directional and horizontal circular mine workings (wells) in the context of the earth's crust for a comprehensive study of the geological structure of the depths, exploration and production of solid, liquid and gaseous minerals, mainly hydrocarbons - oil, condensate and natural gas, carried out with the help of a drilling tool, including (from bottom to top) rock-breaking agent - a chisel, calibrators, section of heavy drill pipes (UBT), turbine, screw or electric electric downhole motor, block of the system for telecontrol of orientation and stabilization of the borehole, horizontal section of drill pipes (BT), vertical section of drill collars and vertical section of BT [1]. At the same time, with the help of a pumping group of ground-based drilling equipment, drilling fluid is circulated in the well to ensure timely removal of drill cuttings from the bottomhole zone and the entire annular space between the drill string and the borehole wall. In the process of formation of the design of the borehole at certain stages of the advancement of the bottom hole in a given direction, subsequent one-dimensional sections of the open hole are fixed with casing strings with cementing the annular space between them and the borehole wall. At the same time, the ultimate capabilities of the traditional drilling method used (in particular, according to the criteria of the maximum allowable depth and length of the well being constructed of an oblique directional and horizontal well) are determined by the allowable intensity of the created stress state of the applied pipes and other components when building the length of the wellbore, descent and tool lifting cycles and operations performed to eliminate the consequences of possible accidents (breaks in drill pipes) and geological and technological operations ozhneny.

In the process of sinking the horizontal part of the barrel at the transition point from the previous curvilinear interval to the corresponding rectilinear part, due to the weight of the drill collars placed higher in the vertical barrel, the tangential force P _{t is} created and maintained at the optimum level, the vector of which corresponds to the direction of supply of the horizontal part of the tool towards the face moreover, this effort is changed (increased) depending on the incremental length of the horizontal section of the well, corresponding to an increase in the length of the drilling tool and the growth of resistance forces to axial displacement and its rotation in the wellbore.

The traditional method outlined for drilling directional and horizontal exploratory and production wells for oil and gas has limitations on the maximum permissible length of the horizontal part of the well moving away from the vertical. So, for example, when using steel drill pipes TB VK 140x12 in the horizontal part of the tool (the specific gravity of pipe assemblies with locks is 78.5 kN / m ³ ) in the process of drilling a horizontal well under the influence of a tangential force of 250 kN (with flushing the well mud specific gravity of 12.0 kN / m ³⁾ of the horizontal portion of the length limit of the boring tool will be only 1,736 m, and it seems clear that this major limiting component largely depends on the weight per unit length races atrivaemoy drill string section.

In particular, when using a drilling tool assembled from titanium and aluminum pipes (with an average specific gravity of pipe assemblies with locks of 45.40 and 32.93 kN / m ³ , respectively), made in the same dimensions of 168x11, and maintaining other conditions of the previous example the maximum permissible lengths of horizontal sections of the drilling tool are determined respectively at 3460 and 5516 m. However, these indicators far from satisfy the modern requirements for the geological and technical characteristics of inclined and horizontal ny wells. Currently, highly effective technical means and technologies are required for drilling directional and horizontal wells with real shaft waste from a vertical length of up to 10,000-12,000 m.

 The solution to this problem based on the modification of traditional technical means and technologies is associated with the faster growth of the required resource consumption of the processes of drilling and securing shafts, opening, development and operation of productive facilities, which, on the one hand, necessitates the use of more powerful drilling equipment (according to the criteria for lifting capacity winch complex, hydraulic power, capacity (displacement) and working pressure of the pumping group, power, load capacity and maximum cr damping torque of the rotor or top drive to rotate the entire drilling tool, etc.), and on the other hand, it inevitably increases the risk of a prohibitive increase in man-made loads on rocks and fluids exposed by an extra-long well, which in most cases leads to unauthorized hydraulic fracturing and contamination of the near-stem formation zone , including productive reservoirs of developed oil and gas objects.

 In light of the foregoing, there was a need to develop based on resource-saving control of the properties of the used pipe (drill, casing, other purposes) columns and the hydraulic medium containing these columns, that is, alternative to traditional new technical means and technologies for drilling and completion of directional and horizontal wells with demanded transcendent ( in comparison with the currently achieved) geological and technical parameters and the waste of the trunks from the vertical.

 The aim of the invention is to increase the deviation of the wellbore of an inclined directional and horizontal well from the vertical above the maximum permissible values (according to the criteria of modern practice for building wells of this purpose) to achieve and open a fishing facility prohibitively distant from the wellhead, to implement directional drilling of the wellbore inside its oil and gas reservoir, providing its intensive drainage and the effectiveness of geological and geophysical research, we optimize ation test modes formation, product selection (oil, condensate, gas, etc.) injection of special fluids, and reagents for improving the performance properties of the reservoir and the adjustment reservoir pressure.

 To achieve this goal, in sections of the trajectory of formation and phased attachment of an inclined directional and horizontal wellbore, in particular, on the approaches and within the reservoir of a productive object, in the wellbore, conditions for partial or complete weightlessness of the pipe (drill, casing, other purpose) string are created by adjusting the given specific gravities of the components of its corresponding pipe products and the enclosing drilling fluid circulating in the well.

 Given these basic canonical methods for regulating the specific gravity indicators of pipe (drill, casing, other purposes) columns, “worked out” as part of a drilling tool, or run to create permanent support in an inclined or horizontal section of the trunk of a super-extended well being constructed, on the one hand , and the drilling fluid containing these columns, on the other hand, provides the opportunity due to the technological necessity to choose the gravity mode of mining of a tubing string (of a whole section or part of a section to be opened) of a pipe string: when the ratios of the specific gravities of pipe products and flushing fluids are characteristic of traditional classical technologies of drilling processes, or when artificially created and maintained in the (obliquely directed, horizontal) wellbore, partial or the complete zero gravity of the drilling tool, the descent casing and pipe strings of other purposes.

буровой гидросреде варьируют и фиксируют на расчетном уровне в диапазоне:

где l_т - длина части трубной колонны, используемой в наклонно направленном и/или горизонтальном участке ствола скважины, м;
К_пф - текущий регулируемый коэффициент потери веса трубной колонны;
γ_p - удельный вес буровой гидросреды, кН/м³;
γ_пт - средний приведенный удельный вес трубных изделий - комплектующих части трубной колонны, используемой в наклонно направленном и/или горизонтальном участке ствола скважины, кН/м³;
К_пфб - базовый коэффициент потери веса трубной колонны, определяемый на исходной позиции - до создания расчетного состояния невесомости рассматриваемой части трубной колонны длиной l_т в буровой гидросреде.Partial weightlessness is achieved and maintained if the current adjustable weight loss coefficient of the tubing string

the hydraulic fluid environment is varied and fixed at a design level in the range of:

where l _t is the length of the portion of the tubing string used in an oblique and / or horizontal section of the wellbore, m;
To _pf - the current adjustable weight loss coefficient of the pipe string;
γ _p - the specific gravity of the drilling fluid, kN / m ³ ;
γ _pt - average reduced specific gravity of pipe products - component parts of a pipe string used in an inclined and / or horizontal section of a wellbore, kN / m ³ ;
To _PFB - the basic coefficient of weight loss of the pipe string, determined at the starting position - until the creation of the calculated state of zero gravity of the considered part of the pipe string with a length of l _t in the drilling fluid.

Тогда Lim l_т→ ∞;
если: 1. γ_пт→ γ_p;
2. γ_p→ γ_пт.
В этих условиях длина предельно допустимой части трубной колонны, используемой в наклонно направленном и/или горизонтальном участке ствола скважины, стремится к бесконечности. Вследствие этого исчезают все зависящие от веса нагрузки на элементы конструкции самой колонны, на стенку ствола скважины, исчезают также зависящие от весовых нагрузок составляющие сил трения (при осевых перемещениях колонны и вращении) труб о стенку скважины. Тем временем конструкционная прочность материала трубной, в частности, бурильной колонны "расходуется", в основном, на передачу осевой нагрузки по вектору действия тангенциального усилия P_т в сторону забойного двигателя и долота, что позволяет поддерживать заданную оптимальную осевую нагрузку последнего на забой.Zero gravity is achieved and maintained if the current adjustable weight loss coefficient of the pipe string is zero, i.e.

Then Lim l _t → ∞;
if: 1. γ _pt → γ _p ;
2. γ _p → γ _pt .
Under these conditions, the length of the maximum permissible part of the pipe string used in an inclined direction and / or horizontal section of the wellbore tends to infinity. As a result of this, all load-dependent loads on the structural elements of the string itself, on the wall of the wellbore disappear, and the friction force-dependent components (with axial movements of the string and rotation) of the pipes against the well wall also disappear. Meanwhile, the structural strength of the material of the pipe, in particular, the drill string is "consumed", mainly, for transmitting the axial load along the action vector of the tangential force P _t towards the downhole motor and bit, which allows you to maintain the specified optimal axial load of the latter on the bottom.

In a state of complete weightlessness on the path of action P _t, this force will be "spent" to a minimum degree to overcome the resistance forces that are not dependent on the weight of the components of an inclined or horizontal part of the drilling tool.

The coefficients K _pfb and K _{pf of} various pipe products used in the drilling fluid medium of a given specific gravity, for example, equal to 12 kN / m ³ , are determined by calculation. The accuracy of these calculations is verified experimentally by weighing the pipe editions immersed in the drilling fluid before and after lining with plug-in float elements.

Steel, titanium and light-alloy drill pipe products made in dimensions 168x11x9400, equipped with the ability to install and remove sealed annular float elements (specific weight 5.967 kN / m ³ ), have the same passage channel with a diameter of 95 mm.

A more than a multiple decrease in the specific gravity of the tubular products lined with these buoyancy when mining them with a specific gravity of 12.0 kN / m ³ leads to a significant change in the coefficients K _pf compared with the corresponding initial baseline K _pfb .

This is evidenced by the following examples of the dependence of K _pf on the rate of change in the specific gravities of the lined drill pipes:
- steel from 78.5 to 33.6 kN / m ³ (2.34 times) K _pf decreased from the base 0.8471 to 0.6429 (1.32 times);
- titanium from 45.4 to 21.0 kN / m ³ (2.16 times) K _pf decreased from the baseline 0.7357 to 0.4286 (1.72 times);
- light-alloy aluminum from 32.93 to 16.27 kN / m ³ (2.02 times) K _pf decreased from the base 0.6356 to 0.2624 (2.42 times);
- aluminum alloy 164x9 in size - from 34.07 to 15.596 kN / m ³ (2.18 times) K _pf decreased from the base 0.6478 to 0.2306 (2.81 times).

With a tangential force of 250 kN pushing the boring tool toward the bottom of the well in a portion of a conventionally straight horizontal bore, the calculated lengths of the drill string equipped with these lined tubular products increase, all other things being equal (compared to the basic version of the use of non-lined steel pipes), respectively, in the order mentions:
- 1.17 times (from 1732 to 2030 m);
- 2.81 times (up to 4870 m);
- 5.95 times (up to 10310 m);
- 7.67 times (up to 13291 m).

Thus, the creation and maintenance for a specified time of the estimated states of partial or complete zero gravity of pipe (drill, casing, other purposes) columns worked out or lowered to create permanent support in an inclined or horizontal (or in both) borehole, provide resource-saving technical and technological conditions for the multiple increase of horizontal well waste from the vertical. Thanks to this, it is possible to develop, with the help of such super-long wells, oil and gas reserves, preserved in vast conservation areas and water areas, as well as hydrocarbon reserves from many hundreds of “small” so far unclaimed (with reserves of cat. A + B + C ₁ less than 10 million r) remote satellite fields, the development and development of which using traditional technical means and technologies for drilling, completion and operation of wells are so far considered unprofitable.

 The above indicates that, in a combination of practical scientific and technical solutions, the claimed method of drilling an oil well and gas of a directional and horizontal well acquired a new effect-forming function of system resource saving, expanding its technical and technological capabilities, and a significant increase on this basis of technically achievable waste from the constructed wells from the vertical. Moreover, the distinguishing features of novelty and industrial utility of the proposed method are significant.

The invention is illustrated by diagrams and drawings:
In FIG. 1 shows a diagram of a drilling tool used for sinking a horizontal wellbore; in FIG. 2 - a drill pipe lined with inserted poplar elements; in FIG. 3 - a device for fastening wells (general view - Fig. 3, a) and a scheme for removing lightweight coating (Fig. 3, b) from the inner surface of the casing after the formation of a cement sheath in the annulus of the well.

 In FIG. 4 shows a casing string for deep wells equipped with removable inventory long float elements; in FIG. 5 is a diagram of the opening of super-extended horizontal wells of oil and water-saturated parts of the reservoir.

 In FIG. 6 shows a layout of envelope shafts of horizontal production and injection wells intensively draining oil and water-saturated parts of the reservoir of the reservoir; in FIG. 7 is a diagram of the opening of an over-extended horizontal well of a production facility lying far beyond the infrastructure facilities, which are directly protected from the risks of hydrocarbon pollution.

 The drilling method is implemented as follows.

 Let us suppose that the drilling of a horizontal well is carried out in accordance with a detailed design providing for the formation of a wellbore along the profile shown in FIG. 1, using a drilling tool, including a bit 1, a calibrator 2, a section of heavy drill pipe (UBT) 3, a downhole motor 4, a block of the telecontrol system for orientation and stabilization of the barrel 5, a horizontal section of drill pipes 6, a vertical section of a drill pipe 7 and a vertical section of drill pipes 8.

Upon completion of the drilling of the curved part of the well AB at point B, the horizontal hole is started to be drilled, and the used drilling tool system, including the vertical section of drill collar 7, allows creating a tangential force P _t equal to 250 kN at this point. Flushing wells with a diameter of 269.9 mm is carried out by a drilling fluid with a specific gravity of 12.0 kN / m ³ . The layout of the bottom of the drill string (BHA) with a length of 12 m weighs 20 kN in air. Conditionally accepted the same - 0.35 average coefficients of friction between the main groups of components of the drilling tool (pipes, BHA elements) and rocks exposed by the well.

The block of the control system for orientation and stabilization of the wellbore 5 ensures accurate removal of the horizontal well to the production site for endogenous opening of the reservoir, and thanks to the use of centering devices, longitudinal bending of the horizontal section of the drill string with a length of l _bt worked out in the section BC of the wellbore is eliminated. In accordance with the assignment of the customer, it is required to drill this well with a horizontal well offset 12,000 m from the vertical. Under the aforementioned limiting technical and technological conditions and the use of assorted steel drill pipes, it is possible to ensure the horizontal part of the well is drilled only to the level of 1732 m from the vertical. Nevertheless, the task is feasible if, to complete the drilling tool that is being worked out during the entire horizontal part of the well, instead of steel pipes, alloy pipes lined with buoyancy ABT 168x11 in size will be used (Fig. 2), each of which includes a pipe case 1, lock clutch 2 and nipple 3, inventory plug-in annular float elements 4, intra-coupling 5 and intra-nipple 6, float linings, as well as o-rings 7.

As a result of equipping the LBT 168x11 alloy drill pipe with buoyancy, the reduced specific gravity of this product is reduced from 32.93 to 16.27 kN / m ³ . Thus, the weight loss coefficient is reduced from the original base K _pfb = 0.6356 (pipes are not lined) to the current K _pf = 0.2624 (pipes are lined with the aforementioned buoyancy). As a result of this, the maximum permissible length of the drill tool section l _{bt is} increased from 5504 to 10310 m (1.87 times more than the initial indicator).

Indicator l _bt can also be increased due to the increase in the specific gravity of the drilling fluid circulating in the well during its penetration. As a result of increasing this parameter from 12.0 to 14.0 kN / m ³ , ceteris paribus, l _bt will increase from 5504 to 6088 m (only 10%).

The greatest technological effect is achieved while controlling the specific gravity of the drill pipe and the hydraulic medium enclosing them. In this case, the task is reduced to assessing the result of a simultaneous decrease in the specific gravity of LBT 168x11 from 32.93 to 16.27 kN / m ³ and an increase in the specific gravity of the drilling fluid from 12.0 to 14.0 kN / m ³ . In this case, the basic indicator K _pfb = 0.6356 is reduced to the current adjustable weight loss coefficient of the horizontal part of the drilling tool K _pf = 0.1395. Under such circumstances, the maximum permissible length of the horizontal section lined with buoyancy drill pipes l _bt , worked out along the entire horizontal bore BC (Fig. 1), increases from 5504 to 19406 m (3.53 times more than the original indicator).

 In light of the above, based on the use of ABT 168x11 floating alloy drill pipes lined with buoyancy and adjusting the specific gravity of the drilling fluid, it is possible to drill a horizontal well with a 12,000-meter vertical offset using standard ground-based drilling equipment.

Highly critical stages of the entire drilling and completion cycle of a horizontal well are technologically interrupting the process of drilling the hole, the operations of fastening and cementing successive one-dimensional intervals of the open hole at the stages of formation of the well design. To reduce the loads on the pipes, on the hook of the derrick and on the walls of the well, due to the weight of the part of the casing string of length l _from , lowered and pushed in the horizontal shaft under the influence of the tangential force P _t , a device for fastening wells is used, including (see Fig. 3 a) sections 5 of the casing with an element 4 fixed on their inner surface from a specific gravity material less than the specific gravity of the drilling fluid 2 filling the well 1. In the process of connecting the sections 5, rings are installed between their ends a gasket 3 made of the same material as element 4.

 After cementing the casing and forming a cement ring 6 in the annulus (see Fig. 3, b), the lightening element 4 is removed if necessary from the inner surface of the sections 5, for example, using a drill bit 7 or in any other way that does not cause wear of the metal of the casing .

 As an alternative to the described device for securing wells, an even more technologically advanced method has been developed for temporarily increasing the buoyancy of a casing string lowered into a horizontal shaft, including casing sections 1 with a sleeve 2 and a shoe 3 (Fig. 4). To increase the buoyancy of the casing string, long float elements 4 are installed in its cavity, each of which is equipped with centralizer ribs 5, a connection unit 6 equipped with a drive shaft 7 with a nipple 8. Long elements are connected to an assembly on a thread made on metal reinforcing tips - a nipple 9 and clutch 10, mounted on long elements.

 At the end of the complex of the mentioned works related to fixing the next interval of the open hole, long float elements are remotely disconnected from the casing wall and raised to the surface for reuse at another drilling facility.

 Creating conditions for partial or complete weightlessness of the pipe (drill, casing, other purpose) string in a drilled directional or horizontal well with a large deviation from the vertical from the vertical opens up favorable opportunities for opening, researching, testing the formation and selecting products under technological conditions that ensure enhanced oil and gas recovery of the developed field facility.

 For example, it is required to carry out the development of a remote oil reservoir using ultra-long horizontal production and injection wells (Fig. 5). Productive formation 1 contains oil 2 and water 3, naturally separated along the plane of the oil-water contact (WOC) 4. The productive formation lies between the cover formations 5 and 6, composed of impermeable rocks, and the underlying formations 7 and 8. The production wells 9 and 10 are opened, respectively lower and upper parts of the oil reservoir. A water-saturated part of the reservoir (below the bottom hole) was opened by the injection well to carry out overflow water flooding in order to compensate for the drop in reservoir pressure and intensify oil recovery.

 Under the weightless state of the pipe string created and maintained during the formation and fastening of the trunk inside the oil and gas and water parts of the productive manifold, when all the loads, depending on the weight of the component parts of the pipe, practically disappear, ideal conditions are established to increase the drainage of the remote oil and gas reservoir by horizontal production and injection wells.

 Due to the maintenance of the partial or complete zero-gravity state of the corresponding section of the drilling tool during the opening of the collector, equipped with a modern system for controlling the orientation and stabilization of the mine working, drainage of the oil and gas and water pressure parts of the collector is carried out along a curvilinear envelope (for example, along the perimeter of the oil-water contact), spiral-screw or any other special curved path connecting local isolated highly permeable from, low permeability oil and gas bearing volume zones of a genetically heterogeneous reservoir.

 Examples of placement of envelope shafts of horizontal boreholes intensively draining the reservoir along its entire edge inside the perimeter of the reservoir 1 in its oil-saturated 2 and water-saturated 3 parts, separated by the oil-water contact plane 4, are shown in FIG. 6. The reservoir lies on the underlying formations 5 and 6. The lower and upper parts of the oil reservoir are opened at two levels by production wells 7 and 8. The water-saturated part of the reservoir was opened by injection well 9.

 In this regard, it should be noted that such predetermined curvilinear penetrating the entire volume of the reservoir, covering the production and injection wells, essentially form systems of intensive drainage of the reservoir, which contribute to the intensification of oil flow from its oil-bearing stratum to production wells, and increase the injectivity of the porous medium of the water-pressure part formation when injecting fluid through injection wells to compensate for the drop in reservoir pressure.

 Another positive consequence of the application of this technology is the possibility of a significant reduction in the level of created depression on the formation during production selection, on the one hand, and a decrease in the working pressure of fluid injection into the water-pressure part of the formation, on the other. Both are beneficial from a technological and economic point of view, especially if we consider these opportunities in light of the growing urgency of the problem of energy conservation during the drilling and operation of superlong horizontal wells.

 An example of a possible implementation of a horizontal well drilling method for developing an oil field deployed in the bowels of the sea at a distance of about 12,000 from the wellhead is shown in FIG. 7. A horizontal well 1 drilled from a bush 3 with a trunk offset of 12,000 m from a vertical passed a mountain range 4, megalopolis 5, a conservation area (relict forest) 6, a recreation area (beach) 7 and opened an oil reservoir 2 at a depth of 3000 m in the bowels of the conservation zone - the coastal waters of the offshore 8. Therefore, all environmental protection objects, including the coastal waters, were out of danger of hydrocarbon pollution.

 The above examples and calculations confirm the technical feasibility and economic feasibility of introducing the inventive method of drilling directional and horizontal exploration or production wells for oil and gas using modern structural materials and drilling equipment.

Sources used in the description of the invention:
1. Kalinin A. G., Nikitin B. A. Increasing gas and oil recovery of a productive formation while drilling horizontal and branched-horizontal wells. // M .; VNIIOENG, 1995 .-- 76 p.

 2. A. p. 1229301 USSR, cl. E 21 B 17/00. Device for fastening wells / L. N. Shadrin (USSR). - N 1354244/03 // BI. N 17.- 1986.

 3. Patent 2015293 of the Russian Federation, cl. 5 E 21 B 17/00. Drill pipe / L.N. Shadrin (RF). - N 5000183/03 // BI. N 12 - 1994.

 4. Patent 2017928 of the Russian Federation, cl. 5 E 21 B 17/00. Casing string for deep wells / L.N. Shadrin (RF). - 4798269/03 // BI. N 15 -1994.

 5. Patent 2074946 of the Russian Federation, cl. 6 E 21 B 17/00. Drill pipe with external lightweight coating / L. N. Shadrin (RF). - N 5060739/03 // BI. N 7-1995.

Claims (2)

1. The method of drilling a directional and horizontal exploratory or production well for oil and gas, including sinking with flushing of the hydraulic fluid of the face and the entire space of the mine working - a given profile of the round cross-section with a rock cutting tool mounted on the shaft of a turbine, screw or electric downhole motor connected with a drill pipe string, fixing each consecutive one-dimensional section of the open hole with casing pipes, as well as opening, testing and stimulating the increase in oil and gas recovery of a productive object, characterized in that, in sections of the formation path and phased attachment of an inclined directional and horizontal trunk, in particular, on the approaches and within the reservoir of a productive object, in a wellbore of a well being drilled selectively create and maintain conditions for partial or complete weightlessness of the pipe columns by adjusting the specific gravities of the components of its tubular products, equipped with lightweight coatings and other means temporarily to increase the buoyancy that accompanies these products of the hydraulic fluid, or both, the calculated indicators of the state of zero gravity of the part of the tubing string of length l _t used in an inclined and / or horizontal section of the wellbore are characterized by the following conditions: partial zero gravity; partial zero-gravity state is achieved and maintained if the current adjustable weight loss coefficient of the pipe string

in the hydraulic fluid environment vary and fix at a design level in the range

where l _t is the length of the portion of the tubing string used in an oblique and / or horizontal section of the wellbore, m;
To _pf - the current adjustable weight loss coefficient of the pipe string;
γ _p - the specific gravity of the drilling fluid, kN / m ³ ;
γ _pt — average reduced specific gravity of pipe products — component parts of a pipe string used in an obliquely directed and / or horizontal section of a wellbore, well, kN / m ² ;
To _PFB - the basic coefficient of weight loss of the pipe string, determined at the starting position - until the creation of the calculated state of zero gravity of the considered part of the pipe string with a length of l _t in the drilling fluid;
total weightlessness; the state of complete weightlessness is reached and maintained if

then liml _m → ∞; if,
1. γ _pt → γ _p ;
2. γ _p → γ _pt .  2. The drilling method according to claim 1, characterized in that to increase oil and gas recovery revealed by horizontal wells of a remote productive object by eliminating the negative effects of natural heterogeneity of gas, oil and water saturation of the reservoir, while maintaining the regime of partial or complete zero gravity the tubing string, the shafts of production and injection wells are guided along a curved envelope, spiral-helical, other special trajectory connecting local isolated volumetric zones to the collector in the corresponding gas, oil and water saturated parts of the developed reservoir.

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