RU2605104C2 - Methods and apparatus for increasing the reach of coiled tubing - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: group of inventions relates to methods and apparatus moving a rod or pipe through a cylinder. Method of delaying the onset of buckling in an elongated structure, traversing a tubular path, comprises the following steps: adapting at least one of the outer surface of the elongated structure and the inner surface of the tubular path to increase a coefficient of friction between the outer surface of the elongated structure and the inner surface of the tubular path in a first direction while maintaining or decreasing a coefficient of friction between the outer surface of the elongated structure and the inner surface of the tubular path in a second direction; and inserting said elongated structure into the tubular path. Apparatus wound about a reel, and for use in a tubular path.

EFFECT: increased reach of coiled tubing by delaying the onset of buckling.

24 cl, 13 dwg

Description

FIELD OF TECHNOLOGY

The present invention generally relates to methods and apparatus for moving a rod or pipe inside a cylinder. Some examples of the invention relate to flexible pipes and the use of flexible pipes in wells in hydrocarbon fields. In addition, the present invention relates, inter alia, to a method for increasing the travel distance of flexible pipes by delaying the occurrence of twisting.

BACKGROUND

Flexible pipes are metal pipes supplied on large diameter drums that are used to perform work in oil and gas wells, and in some cases, function as production pipelines in gas wells of depleted fields. The implementation of downhole operations using flexible pipes usually involves the use of at least three main components. Flexible pipes are delivered on drums and, therefore, in the process of performing work, they are wound on and reeled off from the drum. A flexible pipe extends from the drum to the injector. The injector provides pipe feed into the well and extraction from the well. A guide device or elbow is provided between the injector and the drum. The guide elbow is usually mounted or secured to the injector, and performs the function of determining the direction and support of the flexible pipe supplied from the drum to the injector. Typically, the guide device is attached to the injector at the point of introduction of the pipe into the injector. As the flexible pipe is wound onto the drum and unwound from the drum, the pipe moves from one side of the drum to the other (between the sides of the drum).

In each string of continuous flexible pipes, residual bending is maintained. During storage and transportation, plastic deformation (bending) of the string of flexible pipes wound around the drum occurs. In the process of downhole operations, the flexible pipe is unwound (bending occurs) from the drum and is bent in the guide bend before entering the injector and the well. Residual bending is one of the technical problems of performing work using flexible pipes, which is due to the winding of the flexible pipe on the drum. Although the drums are made of the largest possible diameter in order to reduce the residual bending of the flexible pipe, due to restrictions due to storage and transportation requirements, the maximum diameter of a large number of drums is limited to a few meters.

In the process of using the flexible pipe, a condition called spiral twisting may occur, which leads to blocking of the pipe in the well. The presence of residual bending of the flexible pipe increases the likelihood of spiral twisting and blocking. When a flexible pipe is fed through the wellhead injector, the pipe also passes through the guide device, however, a certain deformation due to residual bending is retained. This deformation leads to a spiral bending of the pipe located in the well and axial twisting along the wall of the well with the formation of a shape similar to a long stretched spring. Ultimately, after a considerable length of flexible pipe is lowered into the well, forces due to friction between the wall of the well and the flexible pipe lead to bending and blocking of the pipe, as a result of which the pipe stops moving inside the well. Blocking prevents further movement of the flexible pipe by applying force to the surface (Lubinski, A., Althouse, W. S., and Logan, J. L., Helical Buckling of Tubing Sealed in Packers, SPE 178, 1962). This blocking restricts the use of coiled tubing as a means of delivering logging tools in wells that have a significant slope, horizontal wells, or uphole sections.

There are a significant number of ways to increase the distance of movement of flexible pipes. Some methods include the use of traction devices, columns of flexible pipes with a variable wall thickness, combined materials, for example, flexible pipes made of composite materials, vibrators, guiding devices, friction reducers and filling the flexible pipe with liquid having a low density.

SUMMARY OF THE INVENTION

This brief description of the invention is presented with the aim of considering a number of concepts, which are further indicated below in the detailed description. This description does not provide a definition of the main or essential features of the claimed invention and does not limit the scope of the invention.

Some embodiments of the invention relate to a method for delaying the occurrence of twisting of an elongated structure comprising an outer surface that moves along a tubular channel having an inner surface. The specified method includes the step of modifying at least one surface from among the outer surface of the elongated structure and the inner surface of the tubular channel in order to increase the friction coefficient between the outer surface of the elongated structure and the inner surface of the tubular channel in the first direction while maintaining or decreasing the friction coefficient between the outer surface the elongated structure and the inner surface of the tubular channel in the second direction and the step of introducing the specified elongated structure urs the tubular channel.

Some embodiments of the invention relate to a device wound on a drum and intended for use in a tubular channel. Said device comprises a hollow pipe wound on a drum, which is a flexible pipe having a length of at least 1000 feet in the state that is wound from the drum and an outer diameter ranging from 0.75 inches to 5.0 inches and modified to obtaining at least one of the following characteristics: (i) anisotropic bending resistance; and (ii) an outer surface providing an increase in the coefficient of friction between the outer surface and the inner surface of the tubular channel in the first direction while maintaining or decreasing the coefficient of friction between the outer surface and the inner surface of the tubular channel in the second direction.

Additional features and advantages of the present invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a detailed description of the present invention with reference to these figures illustrating embodiments of the present invention, which are not restrictive.

Figure 1 shows a graph of the axial load of a flexible pipe as a function of the measured depth of the well.

Figure 2 shows a graph of the axial load of a flexible pipe as a function of the measured well depth as it approaches the blocking state.

Figure 3 shows a flexible pipe with a raised surface.

Figure 4 presents the modified inner surface of the casing.

5A and 5B show a cross section of a flexible pipe having anisotropic characteristics in cross section.

Figure 6 presents the configuration that provides anisotropic stiffness characteristics of the flexible pipe.

7 shows another example of a configuration providing anisotropic stiffness characteristics of a flexible pipe.

FIGS. 8A and 8B show stripes having different cross-sectional sizes from which a flexible pipe with anisotropic bending resistance characteristics can be made.

8C and 8D show a strip that is bent and welded to form a pipe.

FIG. 8E is a partial cutaway view of a pipe obtained by bending and welding the strip indicated in FIGS. 8C and 8D.

DETAILED DESCRIPTION OF THE INVENTION

The features of the present invention described herein are provided by way of example and illustration only when discussing embodiments of the invention. The examples are considered in order to present the most effective characteristics, as well as simplify the understanding of the principles and conceptual features of the invention. In this regard, the details of the design are presented only to the extent that is required for a full understanding of the invention, and the description is carried out using the drawings, providing specialists in this field of technology the ability to determine methods for the practical implementation of various variants of the invention.

In known systems designed to perform downhole work, pipes are presented in the form of a continuous pipe wound on a drum. Depending on the diameter of the pipe (usually the outer diameter is in the range of 0.75 inches to 5 inches) and the size of the drum, the length of the flexible pipe can be in the range of at least one thousand feet to 15,000 feet and even more. The pipeline or pipe is straightened before being introduced into the borehole or borehole (in this document, the two terms are used interchangeably) and is moved by gravity or by means of an injector that feeds the pipe from the surface. Regardless of the method of feeding to the end of the flexible pipe, which is fed into the well, the load is not applied. Due to friction between the flexible pipe and the wall of the horizontal well, the axial compression load of the flexible pipe increases as the distance of movement increases.

A typical example of a change in the axial load of a pipe as a function of the measured well depth is shown in FIG. A well containing a pipe under the load indicated in FIG. 1 consists of a vertical section of 4000 feet long, a transition section (bend) of 600 feet that deviates from the vertical (at a speed of about 15 ° to 100 feet), and horizontal section extending to the end of the well. As indicated in FIG. 1, the pipe is approximately 7600 feet deep into the well, with the first 3200 feet working in tension (load greater than zero) and the rest of the pipe working in compression (load less than zero).

If the horizontal section of the well has a significant length, then the axial compression force reaches a value sufficient to twist the pipe. The first twisting mode is called “sinusoidal twisting”. In this mode, the flexible pipe zigzags along the bottom of the well with alternating bends. This twisting mode is not considered particularly unfavorable, since neither internal stresses nor stresses due to friction increase significantly. As the axial load of compression increases, the flexible pipe goes into the second twisting mode, which is called “spiral twisting”. In this mode, the flexible pipe takes the form of a spiral or moves, clinging to the wall (of the well). For a typical cylindrical pipe, the specified mode of spiral twisting occurs when the predicted axial load and the "wavelength" of the bend. When the pipe begins to twist in a spiral, the normal directed force of the impact of the borehole wall on the flexible pipe increases very quickly and such twisting can have quite serious consequences. In particular, spiral twisting causes a proportional increase in the frictional load, which, in turn, leads to an increase in the axial compression load. After the beginning of spiral twisting, the axial compression load increases very quickly to a level that prevents further movement of the flexible pipe in the well. This condition is called "blocking."

Figure 2 shows a graph of the dependence of the axial load on the measured depth of the well, for example, a flexible pipe placed in the well described earlier in Figure 1 (a vertical section of 4000 feet, then a transition section of 600 feet and a horizontal section), which is approaching locked state or almost in this state. According to the graph shown in FIG. 2, the pipe extends more than 9,000 feet into the well, and from the slope of the curve, it can be determined that the pipe twisted on the pipeline in the transition zone, starting at 600 feet from the transition section to the horizontal section of the well. As indicated in FIG. 2, the pipe runs in compression over almost its entire length.

In some embodiments, the occurrence of pipe twisting can be delayed by the formation of certain friction characteristics of the pipe. On the one hand, it is desirable to reduce friction in the axial direction to simplify the movement of the flexible pipe in the well. On the other hand, it is desirable to increase the friction in the transverse direction in order to prevent lateral deformation, which is associated with twisting of the flexible pipe. Thus, embodiments of the invention provide for the formation of a modified surface (s) of the flexible pipe and / or casing of the well, which provides an increase in the friction coefficient between the flexible pipe and the casing in the transverse direction while maintaining a low coefficient of friction in the axial direction.

In particular, in order to reduce the rate of increase in the axial compression load in a horizontal section of an extended length well, it is desirable to maintain a low value of the friction coefficient in the axial direction. In an example embodiment of the invention, the surface of the flexible pipe is modified with respect to a standard smooth cylindrical surface providing isotropic friction resistance in order to increase the friction resistance to displacement in the transverse direction while maintaining low friction resistance to displacement in the axial direction. Figure 3 shows one way to obtain such an anisotropic friction resistance. In this case, the pipe 10 has an outer surface 12, which in the axial direction includes "protrusions" 14 extending along the pipe. The protrusions indicated in FIG. 3 have a triangular cross section and are macroscopic elements (height of the order of a millimeter). However, as examples of non-limiting nature, protrusions of a much smaller size of the order of micrometers or nanometers may also be provided. In addition, protrusions having various cross-sectional shapes may be used. These protrusions 14 provide a decrease in resistance to movement of the pipe 10 in the axial direction and increase resistance to movement in the transverse direction. The increased resistance to movement in the transverse direction provides a delay in the occurrence of twisting. Obviously, in one embodiment, the protrusions 14 may be discontinuous in the longitudinal direction.

In an exemplary embodiment of the present invention, the protrusions 14 provided on the outer surface 12 of the pipe 10 are integral with the pipe 10. In another exemplary embodiment, the protrusions 14 are placed on a thin sleeve, worn on the pipe and fixed to the outer surface 12 of the pipe 10. A thin sleeve can completely cover the outer surface 12 or be a partial relief coating attached to the outer surface 12. In another embodiment, the protrusions 14, made separately, are attached I to the outer surface 12 of the tube. In these examples of the invention, the protrusions 14 provide a decrease in resistance to movement of the pipe 10 in the axial direction and increased resistance to movement in the transverse direction.

In other embodiments of the invention, in order to increase the friction resistance in the transverse direction, the surface of the casing of the well is modified. As indicated in FIG. 4, the well casing 50 has an inner surface 52 including, in the axial direction, “protrusions” 54 extending along the well casing. The protrusions 54 allow the movement of a standard smooth cylindrical pipe (not shown) in the axial direction with low friction resistance and increased transverse friction resistance. Similarly to the pipe surface configuration shown in FIG. 3, protrusions having a triangular cross section and representing macroscopic elements are indicated, however, protrusions of a significantly smaller size can also be provided. In addition, protrusions having various cross-sectional shapes can be used.

In one embodiment, the protrusions 54 on the inner surface 52 of the casing 50 are integral with the casing 50. In another embodiment, the protrusions 54 are placed on a thin sleeve worn on the pipe and secured to the inner surface 52 of the casing 50. A thin sleeve may completely cover the inner surface 52 or be a partial relief coating attached to the inner surface 52. In yet another example embodiment of the invention, the protrusions 54, made separately, attached to the inner surface 52 of the casing. In these embodiments, the protrusions 54 provide a decrease in resistance to movement of the flexible pipe in the casing 50 in the axial direction and increased resistance to movement in the transverse direction.

In additional embodiments of the invention, the flexible pipe 10 and the surface of the casing 50 can be modified so that as a result of interaction with each other provide an additional increase in resistance to movement in the transverse direction. In an exemplary embodiment of the invention, which is not restrictive, the pipe 10 shown in FIG. 3 is placed inside the casing 50 shown in FIG. 4, and the resulting combination provides a high transverse resistance to movement.

In accordance with other embodiments of the invention, the delay in the occurrence of spiral twisting is achieved by modifying the characteristics of the bending resistance of the pipe cross section. More specifically, twisting delay is achieved by using a flexible pipe having anisotropic bending resistance characteristics. Anisotropic characteristics of bending resistance can be obtained by using an appropriate cross-sectional shape of the pipe. As an example, one can imagine an asymmetric (i.e., anisotropic) cross-sectional shape that provides a decrease in pipe bending resistance along one axis in comparison with the other axis.

Spiral twisting of an isotropic pipe or cylindrical unit occurs when the predicted level of axial compression and the value of the wavelength or "own wavelength". With a change in the spatial anisotropy of the characteristics of resistance to bending and the wavelength that does not coincide with the intrinsic wavelength of spiral twisting, a delay in the occurrence of spiral twisting is introduced, which allows to increase the distance of movement of a cylindrical node such as a string of flexible pipes.

Embodiments of the invention encompass methods of forming a string of flexible pipes that delay the occurrence of spiral twisting. In one embodiment of the invention, as indicated in FIG. 5A, the pipe 110 at a certain position has a cross section 110a with anisotropic characteristics. A cross section with anisotropic characteristics provides different bending resistance in different directions. For example, a pipe 110a having a cross section 110, which is shown in FIG. 5A, has less bending resistance in the direction of the axis 2-2 than in the direction of the axis 1-1. In cross section, pipe 110 has a circular outer configuration 112 and an oval inner configuration 114.

In other embodiments, the orientation of the anisotropic characteristics may vary along the length of the pipe. FIG. 5B shows a cross section 110b having a different orientation in a different position of the pipe 110 shown in FIG. 5A. The orientation shown in FIG. 5B is rotated 90 ° with respect to the orientation indicated in FIG. 5A. The implementation of the spatial structure can be represented by various non-restrictive examples that encompass a smooth change corresponding to a specific wavelength, arbitrary change or “jumps” in the orientation of the anisotropic characteristics. You can use any combination or all combinations of these spatial structures that introduce a delay in the occurrence of spiral twisting. The spatial variation of the characteristics can be coordinated with a specific range of diameters of the flexible pipe and the well in order to delay the occurrence of spiral twisting as efficiently as possible.

The formation of anisotropic stiffness characteristics can also be carried out using a significant number of other configurations. FIG. 6 shows a cross section of a pipe 120 having an outer wall surface 122 that is not coaxial with the inner wall surface 124, whereby the pipe 120 has anisotropic characteristics in cross section. 7 shows a cross section of a pipe 130, the inner wall 134 of which in the cross section has a circular configuration, and the outer wall 132 in the cross section has an oval configuration, with the result that the pipe 130 in the cross section has anisotropic characteristics.

In some situations, for example, when drilling wells using a string of flexible continuous pipes, torque is applied to the string. This leads to spiral twisting of the pipe in one direction. In this case, the spatial distribution of the anisotropic characteristics, contributing to spiral twisting in the opposite direction, can prevent the occurrence of spiral twisting.

It is obvious that the manufacturing process of flexible pipes, in General, involves performing longitudinal welding of uniform flat strips. Homogeneous flat strips are welded together by the oblique welding method to obtain a continuous flat strip. Next, rolling a continuous flat strip and welding along the longitudinal axis is carried out to obtain a pipe having a constant outer and inner diameter, with the exception of transitional sections of oblique welding, which may correspond to the transition from one constant inner diameter to another constant inner diameter.

In an example embodiment of the invention, a method of manufacturing a flexible pipe with anisotropic bending resistance characteristics includes the steps of rolling a strip having an inhomogeneous thickness (for example, such as the strip shown in Fig. 8A) to form a pipe with a constant outer diameter and to weld a longitudinal seam. In another embodiment, a method of manufacturing a flexible pipe with anisotropic bending resistance characteristics comprises the steps of rolling a strip having an inhomogeneous thickness (for example, such as the strip shown in FIG. 8A) to form a pipe with a constant inner diameter and to weld a longitudinal seam. In both cases, the resulting pipe has anisotropic characteristics of bending resistance.

In another example embodiment of the invention, a method of manufacturing a flexible pipe with anisotropic characteristics of bending resistance comprises the step of rolling a strip of material, the cross section of which varies in the longitudinal direction, and performing welding of the longitudinal seam. Thus, although the strip whose cross section is indicated in FIG. 8A has a maximum thickness in the center and a minimum thickness at the ends, in a cross section placed, for example, at a distance of one foot, the configuration of the strip can change to obtain the maximum thickness at the ends and minimum thickness in the center, as indicated in FIG. In fact, when viewed in the longitudinal direction, the thickness of the strip has a spiral configuration.

In another embodiment of the invention, a method of manufacturing a flexible pipe with anisotropic bending resistance characteristics includes the step of cutting the strip at an angle indicated in FIG. 8C and welding the strips as shown in FIG. 8D to form a spiral with adjacent ends of the strips on the pipe, depicted in Fig.8E. The resulting pipe can be rolled into a bay in accordance with the need. The anisotropic characteristics of the pipe may be due to the configuration of the weld or the varying thickness of the strip from which the pipe is made.

In some embodiments, the outer diameter of the pipe wound around the drum (as indicated in FIG. 8D) is in the range of 0.75 inches to 5 inches, and the length of the unwound pipe is at least one thousand feet. The pipe has anisotropic characteristics of bending resistance or the outer surface, providing an increase in the coefficient of friction between the outer surface of the pipe and the inner surface of the tubular channel into which the pipe is introduced, in the first direction while maintaining or decreasing the coefficient of friction between the outer surface of the pipe and the inner surface of the tubular channel in the second direction .

The device and methods described herein can likewise be applied in other areas of the oil and gas industry, as well as other industries. Non-limiting examples of the use of the invention are fiber optic cables, wireline cables, and ropes that can be inserted into various cylindrical nodes, non-limiting examples of which are flexible pipes or wells. The use of the present invention in other industries encompasses medicine, and stenting devices and other medical devices are examples of non-limiting use.

Several examples of the invention have been described in detail above, however, it will be apparent to those skilled in the art that various modifications of these embodiments are possible within the spirit of the invention. Although in a non-restrictive example, a cased hole is used as the tubular channel, the tubular channel may be an open hole (wellbore). In addition, in the non-limiting example, a hollow structure (pipe) was used, unwound from the drum and inserted into the tubular channel, however, any elongated structure (usually having a length of at least 1000, can be unwound and inserted into the tubular channel exceeding width), including an elongated continuous structure (bar). Accordingly, such changes are within the scope of the invention defined by the appended claims. Claims describing the means and corresponding functions, if any, encompass the structures described herein and performing the indicated functions, as well as similar elements and equivalent structures. Thus, although a nail and a screw are not equivalent elements, since in the case of a nail, a cylindrical surface is used to fasten wooden parts, and in the case of a screw, a spiral surface, in the area of fastening of wooden components, the nail and screw can be equivalent structures. Applicant does not intend to apply the restrictions arising from the provisions of Section 35 § 112, paragraph 6 of the Code of the United States Law, with respect to any claims referred to in this document, with the exception of paragraphs that use the expression “means for” indicating the appropriate function.

Claims (24)

1. A method for delaying the occurrence of twisting of an elongated structure having an outer surface that extends through a tubular channel having an inner surface, comprising the steps of:
modification of at least one surface from the outer surface of the elongated structure and the inner surface of the tubular channel in order to increase the friction coefficient between the outer surface of the elongated structure and the inner surface of the tubular channel in the first direction while maintaining or reducing the coefficient of friction between the outer surface of the elongated structure and the inner surface of the tubular channel in the second direction; and
introducing said elongated structure into the tubular channel. 2. The method according to p. 1, characterized in that:
said first direction is a transverse direction, and said second direction is an axial direction. 3. The method according to p. 1, characterized in that:
the specified stage of the modification includes the formation of many longitudinal protrusions on the specified outer surface of the elongated structure. 4. The method according to p. 3, characterized in that:
at least one of the plurality of longitudinal protrusions has a generally triangular cross section. 5. The method according to p. 1, characterized in that:
the specified stage of the modification includes the formation of many longitudinal protrusions on the specified inner surface of the tubular channel. 6. The method according to p. 5, characterized in that:
at least one of the plurality of longitudinal protrusions has a generally triangular cross section. 7. The method according to p. 1, characterized in that:
said modification step includes forming a plurality of longitudinal protrusions on said outer surface of the elongated structure and said inner surface of the tubular channel. 8. The method according to p. 1, characterized in that:
the specified many longitudinal protrusions made in one piece with the outer surface of the tubular structure. 9. The method according to p. 1, characterized in that:
the specified set of longitudinal protrusions is made integrally with the inner surface of the tubular channel. 10. The method according to p. 1, characterized in that:
the specified tubular channel is a casing of the well. 11. The method according to p. 1, characterized in that:
the specified elongated structure is formed of a flexible pipe. 12. The method according to p. 10, characterized in that:
said elongated structure is a pipe formed from a flexible pipe. 13. A method for delaying the occurrence of twisting of an elongated structure having an outer surface that extends through a tubular channel having an inner surface, comprising the steps of:
modification of the elongated structure in order to obtain anisotropic characteristics of resistance to bending, and the specified elongated structure includes a spiral weld, and
introducing said elongated structure into the tubular channel. 14. The method according to p. 13, characterized in that:
in the first position, said elongated structure has in cross section a circular configuration of the outer surface and an oval configuration of the inner surface. 15. The method according to p. 13, characterized in that:
in the first position, said elongated structure has in cross section an oval configuration of the outer surface and a circular configuration of the inner surface. 16. The method according to p. 13, characterized in that:
in a first position, said elongated structure has in cross section a first circular configuration of the outer surface and a second circular configuration of the inner surface, wherein said first circular configuration is not coaxial with the second circular configuration. 17. The method according to p. 1, characterized in that:
said elongated structure includes a longitudinal weld. 18. The method according to p. 14, characterized in that:
the orientation of the anisotropic characteristics of the bending resistance of the specified elongated structure varies along the length of the elongated structure. 19. The method according to p. 13, characterized in that:
the specified tubular channel is a casing of the well. 20. The method according to p. 19, characterized in that:
said elongated structure is a special pipe formed from a flexible pipe. 21. The method according to p. 13, characterized in that:
said elongated structure is a special pipe formed from a flexible pipe. 22. A device wound on a drum intended for use in a tubular channel and containing:
a hollow pipe wound around a drum to form a flexible pipe, said pipe after being unwound from the drum, has a length of at least 1000 feet, an outer diameter between 0.75 inches and 5.0 inches, and modified to obtain at least one of the following characteristics: (i) anisotropic bending resistance; and (ii) the outer surface of the hollow pipe, providing an increase in the coefficient of friction between the outer surface of the hollow pipe and the inner surface of the tubular channel in the first direction while maintaining or reducing the coefficient of friction between the outer surface of the hollow pipe and the inner surface of the tubular channel in the second direction. 23. The device according to p. 22, characterized in that:
the specified hollow pipe has anisotropic characteristics of resistance to bending, the orientation of which varies along the length of the pipe. 24. The device according to p. 22, characterized in that:
the specified hollow pipe has an outer surface containing many longitudinal protrusions.

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