TW202244416A - Glider devices and methods therefor - Google Patents

Abstract

Contemplated gliders are configured, coupled to, and placed on a tubular pipe that is surrounded by an outer casing such as to minimize hydraulic resistance of a working fluid passing through an annular space formed between the tubular pipe and casing. Moreover, contemplated gliders not only maintain a desired distance between the pipe and casing, but also facilitate installation and advancement of the pipe into the casing via a low-friction surface, and differential movement between the casing and pipe.

Description

Slider device and method thereof

This application claims priority to co-pending Provisional Patent Application US 63/179088, filed April 23, 2021, which is incorporated herein by reference.

The invention belongs to the field of fluid pipelines, in particular to various nested pipe assemblies used for transporting working fluids in geothermal power generation.

The description of the background art includes information that may be useful in understanding the present invention. It is not an admission that any information provided herein is prior art or related to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

All publications and patent applications herein are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. To the extent that a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference will not apply.

Fixed spacing elements for maintaining the position and distance of the inner tube within the outer tube are well known, exemplary fixed spacing elements are disclosed in patents US4607665 and US5803127. In another known arrangement, the patent US 3306378 discloses a drill collar in which a single spacer fin stabilizes the drill bit during operation. In still further known arrangements, a plurality of radially arranged shims are used to allow sliding movement, such as polymer rod guides for sucker rods, as described in patent US9010418. Other spacers for fuel pipes of coaxial jackets are disclosed in patents WO 2005/106306 and GB 722689, and patent JP 2016-138644 discloses minimum contact spacers.

Patent US 5803127 discloses a pipe-in-pipe system in which hazardous gases are transported in an inner pipe assembly surrounded by an outer pipe assembly in which the purge gas can move. The inner and outer catheter assemblies in such systems are held apart at a fixed distance using symmetrical spacing elements, which advantageously allows the coaxial tubing to bend without crimping and may reduce stress fractures caused by vibration. While such devices and others are required in selected use situations, currently known spacing elements are generally unsuitable for relatively long nested tube assemblies where the inner tube assembly must be advanced through the outer tube assembly for placement and manipulation. Furthermore, presently known spacer elements present significant resistance to fluid flow in the annulus, particularly where such nested pipe assemblies are of considerable length (eg, in excess of 1,000 metres). Such resistance is particularly undesirable when the fluid is a working fluid used to generate electricity, since the efficiency of electricity generation will decrease significantly as the flow resistance of the working fluid increases.

Thus, while various isolation systems and methods for nested pipe assemblies are known in the art, all or nearly all of them suffer from several disadvantages. Therefore, there remains a need for compositions and methods for improving spacer elements in nested tube assemblies.

The subject matter of the present invention relates to various devices, systems and methods for slides in pipe-in-pipe assemblies for transporting working fluids over long distances. Advantageously, the various slides contemplated will not only facilitate advancement of the inner tubular tube assembly through the outer tubular housing, but also minimize inefficiencies and stabilize the positioning of the tubular conduit within the tubular housing.

In one aspect of the inventive subject matter, the inventors contemplate a tube assembly comprising a tubular conduit having an inner surface and an outer surface, and a plurality of slides coupled to the outer surface. Most typically, at least a first slide and a second slide are longitudinally and radially offset relative to each other relative to an imaginary central axis extending along the length of the tubular conduit, and each slide comprises a first material and A second material, wherein the first material is coupled to the outer surface of the tubular conduit, and wherein the second material forms the outer surface of the slide. In a further preferred embodiment, the tube assembly further comprises a third slide having a longitudinal offset and a diameter relative to the first slide and the second slide and to an imaginary central axis extending along the length of the tubular conduit. offset.

Additionally, contemplated tubular conduits may include insulating material disposed between the inner and outer surfaces. Typically, but not necessarily, a plurality of slides are welded to the outer surface of the tubular conduit. In some embodiments, the longitudinal offset between the first slide and the second slide is at least 30 inches, and/or the radial offset between the first slide and the second slide is at least 45 inches. Spend. In other suitable options, the first material of the plurality of slides may comprise steel, and the second material of the plurality of slides may comprise an alloy having a hardness less than that of the first material. Viewed in a different aspect, the second material of the plurality of sliders generally has a lubricity greater than that of the first material. Although not limiting the subject matter of the invention, the first material of the plurality of slides is preferably clad with the second material.

In a further exemplary embodiment, the first slide and the second slide may have an elongated profile extending along an imaginary central axis and also have rounded end portions. Furthermore, it is contemplated that the first slide and the second slide may have a thickness sufficient to force the tubular conduit to be off-center with respect to an imaginary central axis of the tubular housing surrounding the tubular conduit. In still further contemplated embodiments, the tubular conduit has sufficient strength to convey fluid at a pressure of at least 2,000 psi and a temperature of at least 250°F, and/or the tubular conduit has a length of at least 2,000 meters.

In another aspect of the inventive subject matter, the inventor contemplates a duct assembly comprising a plurality of tube assemblies as set forth herein, wherein a tubular housing surrounds the tubular duct, and wherein a plurality of slides can hold the tubular duct The distance between the outer surface and the inner surface of the tubular shell.

For example, the distance between the outer surface of the tubular conduit and the inner surface of the tubular housing can be between 0.25 inches and 1.50 inches or greater. It is further contemplated that the tubular housing and the tubular conduit may be coupled to each other to form a closed loop for circulation of the working fluid, and that the closed loop may also include a heat exchanger and/or a generator. Accordingly, the inventors also contemplate geothermal power and/or thermal power plants comprising the various duct assemblies proposed herein.

In yet another aspect of the inventive subject matter, the inventor contemplates a slide for a tube-in-tube assembly consisting of a first material and a second material coupled to each other and arranged so that, upon installation When entering the space between two tubes in the tube assembly, the first material contacts the outer surface of the inner tube and the second material contacts the inner surface of the outer tube. Most typically, the plurality of sliders have an elongated profile with at least one rounded end portion, eg, an aspect ratio of at least 5:1 and/or an aspect ratio of at least 1:1.

Preferably, but not necessarily, the first material and the second material are coupled to each other by a cladding. For example, the first material may include steel and the second material may include copper and/or aluminum alloys. In further examples, it is contemplated that the elongated profile has a length between 8 and 16 inches, a width between 1 and 2 inches, and/or a thickness between 0.5 and 1.0 inches. If desired, the elongated profile may have side portions parallel to each other, and/or may have rounded end portions of spherical or parabolic profile.

In yet another aspect of the inventive subject matter, the inventors contemplate a method of moving a tubular conduit within a tubular housing, the method comprising advancing the tubular conduit through the tubular housing while maintaining a distance between the tubular conduit and the tubular housing A step of. Most typically, this distance may be maintained by a plurality of slides having longitudinal and radial offsets relative to each other relative to an imaginary central axis extending along the length of the tubular conduit, and the tubular At least 90% of the total friction between the pipe and the tubular housing is borne by the plurality of slides.

In further contemplated embodiments, at least some of the propulsion is in a vertical direction, and/or the coefficient of kinetic friction of the plurality of slides relative to the tubular housing is equal to or less than 0.5. It is further contemplated that the plurality of slides may have a thickness sufficient to force the tubular conduit to be off-center with respect to an imaginary central axis of the tubular housing surrounding the tubular conduit. Generally, the tubular conduit may include an insulating material disposed between the inner and outer surfaces of the tubular conduit. For a suitable plurality of slides, the same considerations above apply.

Therefore, and viewed from a different aspect, the inventors have also conceived a method of reducing power losses in a geothermal installation, the method comprising the step of moving a working fluid in an annular space formed by a tubular duct disposed within a tubular casing, Wherein the annular space is maintained by a plurality of slides between the tubular tube and the tubular housing. wherein the annular space is maintained by a plurality of slides between the tubular duct and the tubular housing. Most typically, each of the plurality of slides has an elongated profile with at least one rounded end portion, and at least a first slide and a second slide are relative to an imaginary central axis extending along the length of the tubular conduit have a longitudinal offset and a radial offset relative to each other.

While many working fluids are considered suitable as heat-carrying working fluids, preferably, the tubular casing and tubular conduit are coupled to each other to form a closed loop for circulation of the working fluid, and/or the tubular conduit and tubular casing have a distance of at least 2,000 meters length.

Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of the preferred embodiment and from the drawings in which like numerals represent like elements.

The inventors have developed a slide that can be advantageously used to accommodate sliding movement between a tubular pipe and a tubular casing, for example in closed loop geothermal applications. Notably, the multiple slides proposed in this paper will not only bear the weight of the tubular pipe, but also provide support to center the tubular pipe and as the pipe slides along the housing during installation and due to thermal variations in axial length Provides lubricity. In addition, the plurality of sliders presented herein have a streamlined profile that prevents or reduces flow resistance of the working fluid in the annular gap between the tubular conduit and the casing surrounding the tubular conduit. In the most typical application, multiple slides are installed along the pipe in an offset orientation to allow the pipe to bend in a deviated well and to accommodate any machining irregularities encountered as the pipe slides along the shell surface, such as the ellipticity. In still further embodiments, at least some of the slides will be somewhat oversized such that slight deflection of the tubular conduit creates compression between the slide and the housing to prevent movement of the conduit when subjected to the forces of fluid flow.

In one exemplary configuration, as shown in the axial view of FIG. 1 , tubular conduit 100 has an inner wall 112 and an outer wall 114 , which may or may not be encapsulated with insulating material 116 . Coupled to the outer wall 114 are three slides 120A, 120B, and 120C, which have equidistant radial and longitudinal offsets. In the example of Figure 1, the radial offsets are equidistant at an angle of 120 degrees. Figure 2 depicts a cross-sectional view at the location with the slide and outer tubular housing. Here, a tubular conduit having an inner wall 212 , an outer wall 214 and insulating material 216 therebetween is located within a tubular housing 230 . The slide is welded to the outer surface 214 of the tubular conduit by a weld 226 . It should be particularly understood that the slider in this example is made of two different materials, a first backing material 224 welded to the outer surface 214 of the tubular conduit and a second cladding material 222 that contacts the inner surface of the tubular housing 230 . It will be appreciated that this choice of different materials is particularly beneficial in at least two respects: the first backing material can be chosen to facilitate welding to the outer surface of the tubular pipe, and the second cladding material can be chosen to reduce slippage friction between the outer surface of the part and the inner surface of the tubular shell (and provides lubricity). Viewed from a different aspect, the first material is preferably similar to the material of the outer wall of the inner tube, thereby allowing direct welding of the first material to the outer wall of the inner tube. On the other hand, the second material may preferably be chosen so as to obtain a lower coefficient of friction between the second material and the inner wall of the tubular housing, as will be described below. Fig. 3 depicts the tubular duct of Fig. 1 in side view to improve the clarity of the longitudinal and radial offsets of the plurality of slides. As shown in this example, each spacer element has a radial offset and a longitudinal offset such that at any given point along the longitudinal axis of the tubular conduit there is only a single slide.

With regard to the tubular conduit and tubular housing, it should be understood that specific sizes and dimensions do not limit the subject matter of the present invention. Accordingly, suitable tubular conduits may or may not have insulating material, and may have the same or different diameters throughout their length. Likewise, the exact inside and outside diameters may vary widely. However, it is generally preferred that the inner diameter be at least 1.0 inches, or at least 1.5 inches, or at least 2.0 inches, or at least 2.5 inches, or at least 3.0 inches, or at least 3.5 inches, or at least 4.0 inches, or at least 4.5 inches, or at least 5.0 inches, or at least 6.0 inches, or at least 7.0 inches, or at least 8.0 inches, or at least 9.0 inches, or at least 10 inches, or even larger. Accordingly, the outer diameter of the tubular conduit may have an outer diameter of at least 3.0 inches, or at least 3.5 inches, or at least 4.0 inches, or at least 4.5 inches, or at least 5.0 inches, or at least 5.5 inches, or at least 6.0 inches, Or at least 7.0 inches, or at least 8.0 inches, or at least 10.0 inches, or at least 12.0 inches, or at least 15.0 inches, or at least 20.0 inches, or even larger diameters.

Most typically, the material of the tubular conduit may vary considerably, and the appropriate choice of material, having regard to the intended purpose, will be apparent to those skilled in the art. Accordingly, suitable materials include various metals and metal alloys, polymers, and all reasonable combinations thereof. However, particularly in the case of conveying a working fluid in a liquid and/or gaseous phase in a tubular conduit, it is preferred that the material of the tubular conduit comprises iron, especially steel (eg mild steel). Among other parameters, materials will be selected so that the working fluid in the tubular piping can have a pressure of at least 500 psig, or at least 1,000 psig, or at least 1,500 psig, or at least 2,000 psig, or at least 2,500 psig, or at least 3,000 psig, or at least 4,000 psig psig, or at least 5,000 psig, and even higher. Similarly, materials will be selected such that the working fluid in the tubular conduit may have a temperature of at least 30°C, or at least 50°C, or at least 80°C, or at least 100°C, or at least 150°C, or at least 200°C , or at least 250°C, or at least 300°C, or at least 350°C, or at least 400°C, and even higher temperatures. Most typically, especially when tubular piping is used in geothermal applications, the length of the piping is at least 500 meters, or at least 1,000 meters, or at least 2,000 meters, or at least 3,000 meters, or at least 4,000 meters, or at least 5,000 meters, or at least 6,000 meters, or even longer.

Accordingly, the tubular housing will be of various materials, sizes and dimensions matching the various parameters of the tubular conduit. Thus, particularly in the case of tubular housings conveying working fluids in liquid and/or gaseous phase, it is preferred that the tubular housing material comprises iron, especially steel (eg mild steel). Among other various parameters, the material will be selected so that the working fluid in the tubular housing can have at least 500 psig, or at least 1,000 psig, or at least 1,500 psig, or at least 2,000 psig, or at least 2,500 psig, or at least 3,000 psig, Or at least 4,000 psig, or at least 5,000 psig, and even higher pressures. Similarly, materials will be selected such that the working fluid in the tubular housing can have a temperature of at least 30°C, or at least 50°C, or at least 80°C, or at least 100°C, or at least 150°C, or at least 200°C C, or at least 250°C, or at least 300°C, or at least 350°C, or at least 400°C, or even higher temperatures. Most typically, particularly when tubular shells are used in geothermal applications, the shell has a length of at least 500 metres, or at least 1,000 metres, or at least 2,000 metres, or at least 3,000 metres, or at least 4,000 metres, Or at least 5,000 meters, or at least 6,000 meters, or even longer.

With regard to the various configurations of sliders contemplated and the arrangement of the plurality of sliders on the outer surface of the tubular conduit, it should be understood that many configurations and configurations are considered suitable so long as the configuration provides at least two The radial offset and longitudinal offset of the slider are sufficient. In at least some embodiments, the slider preferably has a streamlined profile to minimize flow resistance through the annulus. The streamlined shape also allows the sliding part to have enough contact area to bear the load of the insulating tube. Furthermore, it is generally preferred that the slide be contoured on the leading and trailing edges to accommodate smooth fluid flow across the surface. As will be appreciated, the wear surface of the slide must also be durable enough to withstand continued wear over its design life. In terms of further consideration, it should be noted that the thickness of the slides, as well as the spacing between the slides, can support the insulation pipe to prevent sagging, which can create resistance between the insulation pipe and the casing and prevent the return pipe from being nearly concentric within the casing installation.

Thus, in at least some embodiments, the plurality of slides contemplated are spaced apart (longitudinal offset) in the longitudinal direction, and most typically, the longitudinal distance between at least two slides will be 1/4 of the slide length. At least double, or at least triple, or even more. For example, when the slides are between 10 and 15 inches in length, the distance between two (also usually radially offset) slides will be at least 20 inches, or at least 30 inches, or at least 40 inches, or at least 50 inches, or even more. Thus, particularly where the slides also have a radial offset, it is to be understood that there are no more than two slides at any given position, and most typically only one slide, as exemplarily shown in FIG. 3 . Where there are two slides at the same location, the two slides are generally not located on opposite sides of the insulating pipe to avoid compression of the housing which is not perfectly circular.

A particularly preferred method of mounting the plurality of slides to the outer wall of the tubular duct is welding. In this case, it should be noted that instead of welding dissimilar metals directly to the pipe, the slide can consist of two materials: a base plate made of steel that closely matches that of the outer pipe surface, and a The softer plate is fixed to the slide steel plate by various techniques such as cladding. The sliding surface reduces static and kinematic friction, thereby increasing the axial stress on the return pipe when sliding.

For example, with respect to contemplated profiles, it should be understood that preferred profiles for sliders would be elongated and include at least one rounded end portion, thereby reducing resistance and/or turbulence of fluid passing through the annular space. Accordingly, the various slider shapes contemplated may have rounded (eg, spherical) or pointed (eg, parabolic) tips, as exemplarily shown in the three slider examples in FIG. 4 . Here, it should be noted that the specific dimensions provided are exemplary only and should not be construed as limiting the subject matter of the present invention. In fact, it should be noted that multiple slide sizes depend at least in part on the particular dimensions of the duct and casing, but it is generally believed that the width of the slide will not exceed 20%, or 18%, or 16% of the circumference of the outer surface of the tubular duct , or 14%, or 12%, or 10%, or 8%, or 6%, or 4%. With regard to the length of the slide, it is generally envisaged that the length will be at least 4 times, or at least 6 times, or at least 8 times, or at least 10 times, or at least 12 times the width of the slide. With respect to the thickness of the slide, it is understood that the thickness will be such that the slide occupies at least 80%, or at least 85%, of the distance between the outer surface of the pipe and the inner surface of the tubular casing when the pipe and casing are in a concentric position relative to each other, or At least 90%, or at least 95%, or at least 100%, or at least 105%, or at least 110%, or at least 115%, or at least 120%, or at least 125%, or at least 130%. Especially in the case of slides with a thickness of more than 100%, it will be understood that this thickness will assist in elastically deflecting and thus pretensioning the inner tube, which advantageously reduces movement (and possibly also vibrations) of the inner tube, The inner tube is subjected to the flow force of the fluid in the annular space. Thus, viewed from various aspects, the slider may have an elongated shape with an aspect ratio of at least 5:1 and/or an aspect ratio of at least 1:1. Additionally, the plurality of sliders may have parallel side portions or curved side portions, as shown in FIG. 4 .

For example, suitable skid dimensions for geothermal applications would include skids having at least 4 inches, or at least 6 inches, or at least 8 inches, or at least 10 inches, or at least 12 inches, or at least 14 inches, or Those dimensions of at least 16 inches, or at least 18 inches, or even longer, and having a length of at least 0.5 inches, or at least 1.0 inches, or at least 1.5 inches, or at least 2.0 inches, or at least 2.5 inches , or those dimensions of at least 3.0 inches, or even wider widths. Likewise, suitable thicknesses include at least 0.2 inches, at least 0.4 inches, at least 0.6 inches, at least 0.8 inches, at least 1.0 inches, at least 1.2 inches, at least 1.4 inches, at least 1.6 inches, at least 1.8 inches inches, or even thicker.

Regardless of the specific size and geometry, and as noted above, it should be understood that the slider can be composed of at least two different materials to suit various needs. For example, a first contemplated material is suitable for easily coupling the slide to the outer surface of the tubular conduit. Among other suitable modes of coupling, welding is a particularly preferred means, so the choice of the first material will be determined at least in part by the similarity of the materials (eg both the first material and the outer surface are mild steel). In another aspect, the second material will be selected to reduce the friction of the second material against the inner surface of the tubular casing (e.g., to achieve 0.60 or less, or 0.55 or less, or 0.50 or less, or 0.50 or less 0.45, or a kinetic coefficient of friction equal to or less than 0.4). For example, suitable second materials include lubricating metals and metal-free materials such as aluminum and copper based alloys, nickel coatings, boron nitride nickel coatings, fluoropolymer coatings, and the like. It will be readily appreciated that the two materials can be joined in a variety of ways, the exact choice will depend on the particular material chosen. For example, suitable joining methods include cladding, bonding, explosion welding, friction stir welding, and the like. In less preferred aspects it will be appreciated that alternative means of connection such as threaded connections, bolted connections etc. are also considered suitable.

Therefore, the inventors have also conceived a method of moving the tubular duct within the tubular housing, wherein the tubular duct is advanced through the tubular housing while maintaining the distance between the tubular duct and the tubular housing. As mentioned above, this distance is maintained by a plurality of slides having longitudinal and radial offsets relative to each other relative to an imaginary central axis extending along the length of the tubular pipe, the tubular material in this advancing step At least 80%, or at least 85%, or at least 90%, or at least 95% of the total friction with the housing is carried by the plurality of slides. It will be readily appreciated that the position of the tubular conduit and housing may be strictly vertical, or in an angled or curved orientation, or in a horizontal orientation with respect to the normal. Furthermore, preferably, the coefficient of kinetic friction of the plurality of sliders relative to the tubular housing is equal to or lower than 0.6, equal to or lower than 0.5, equal to or lower than 0.4, equal to or lower than 0.3, or even lower. Such low friction is particularly advantageous where the plurality of slides has a thickness sufficient to force the tubular conduit to be off-center with respect to an imaginary central axis of the tubular casing surrounding the tubular conduit.

With regard to multiple slide arrangements, it is generally preferred that multiple slides are coupled to the tubular conduit such that there are no more than two, more typically no more than one slide at any given cross-section of the tubular conduit. From various perspectives, it is conceivable that at least two (more typically most or all) of the slides have a diameter of at least 1 inch, or at least 5 inches, or at least 10 inches, or at least 20 inches, Or at least 30 inches, or at least 40 inches, or at least 50 inches, or at least 60 inches, or more longitudinal offset. Similarly, with respect to radial offset, it is conceivable that at least two (and more typically most or all) slides have a radial offset of at least 15 degrees, or at least 30 degrees, or at least 45 degrees. degrees, or at least 60 degrees, or at least 90 degrees, or at least 120 degrees, or at least 180 degrees. Figure 5 shows an exemplary configuration of radial offset and longitudinal offset, while Figure 6 depicts an end view of the tubular duct of Figure 5 in a tubular housing.

Since the slider provides a narrow contact point between the insulating return tube and the housing, the slider can also have a radius profile on the leading and/or trailing edge to slide over the smaller gaps encountered. Surface imperfections (ie, the thickness of the end portion of the slide is less than the thickness of the center portion of the slide). Such a profile can advantageously be used to protect the insulating return pipe from damage due to rapid stress increases of forces transmitted from/to the slide.

It will be readily appreciated that where this arrangement is used in a geothermal plant, the tubular shell will be subject to heat transfer from the geological formation to the working fluid. In this context, it should be noted that the term "geothermal" as used herein refers to thermal resources found in high-temperature rocks, often deep beneath the Earth's surface, that can be used for industrial power and heat production. Most typically, a thermal resource is a "dry" resource from which thermal energy can be extracted without simultaneously extracting fluids from the geological formation (such as brine from the formation or treated injection water). For example, the tubular conduit and housing may be part of a closed loop system in which a working fluid circulates. Most typically, such a closed loop system will further include heat exchangers and turbines and generators to generate electrical energy, as schematically depicted in Figure 7 and described in patent US 8020382, which is incorporated herein by reference in its entirety.

In this context, it should be understood that closed-loop geothermal technology can harvest (harvest) thermal energy from hot rock into a working fluid that circulates in a completely closed environment. Most typically, closed-loop wells consist of a larger casing tube that is thermally connected to the rock by thermally conductive grout, and an inner insulating tube that returns the heated fluid to the surface. The working fluid flows down through the annular space between the casing and the insulated return pipe, absorbs thermal energy from the rock through the casing wall, and flows up the insulated return pipe to provide energy for a variety of purposes including power generation. Most preferably, the geological formation has a temperature sufficient to convert a liquid working fluid (eg, water) into a gaseous fluid (eg, steam) that is transported to the top and expanded and cooled in an expansion turbine, or sent into A heat exchanger that heats the secondary working fluid of the generator. Examples of closed loop geothermal systems are described in patents US 8201409 and US 2018/0274524, which are incorporated herein by reference in their entirety.

It should also be noted that for many of the methods of geothermal collection contemplated herein, the gap between the housing wall and the insulated return pipe is relatively small (e.g., between 0.2 and 0.4 inches, or 0.4 to 0.6 inches, or 0.6 to 0.8 inches. inches, or between 0.8 and 1.0 inches, or between 1.0 and 2.0 inches). Therefore, without the use of slides, contact between the two parts would be unavoidable during installation of the return pipe. 8 is a photograph showing an exemplary tubular housing enclosing a tubular conduit with partially exposed insulation between the inner and outer surfaces of the tubular conduit. Sliders (not shown in FIG. 8 ) as shown herein provide lubricated surfaces to reduce the possibility of wear between the components. Additionally, the multiple slides minimize possible damage to the housing surface finish, which is preferably smooth after installation to minimize disturbance to fluid flow during long-term operation of the well.

It should be further understood that the contemplated multiple slides also accommodate sliding movement due to thermal expansion and contraction during well operations. Closed loop geothermal wells are typically subject to large temperature fluctuations, and the contemplated multiple slides would allow differential motion between the casing and return pipe caused by temperature changes over at least some of the system's lifetime. Additionally, for operational optimization or maintenance reasons, flow in a closed loop system may be temporarily stopped, causing temperature transients and causing differential motion between the case and the return line. In these cases, multiple slides will help prevent excessive axial stress in the return line.

Finally, it should be noted that, unlike prior arrangements, the slides are not mounted symmetrically in a radial direction around the pipe at a given position. Instead, multiple slides are mounted at offsets along the length of the pipe. Since the slide has only one point of contact along the partial length of the pipe, the pipe can flex to avoid any irregularities encountered on the housing surface. This may enable the slider to accommodate bends, irregularities in machining tolerances and imperfections on the housing surface.

It should also be understood that while the adaptive installation and periodic sliding motion in closed-loop geothermal wells is somewhat similar to the action of centralizers used in rotary drilling, there are a number of unique differences.

First, the loads experienced by the multiple slides proposed in this paper are expected to be modest compared to those observed in rotary drilling. In practice, both return tube installation and cyclical thermal sliding will occur at low speeds, primarily axial (forward and backward) rather than rotational motion. Therefore, multiple slides mounted radially symmetrically at multiple points around the insulating tube would not only be overly redundant, but would also create the potential for high stress build-up in the oval or otherwise deformed profile of the housing. Additionally, the use of fewer components would advantageously reduce the cost and weight of the drill pipe assembly.

Second, unlike conventional rotary drilling equipment, the insulated return line will remain in place for extended periods of time. The insulated return pipe and its supporting components, such as the multiple slides, are not expected to be withdrawn for maintenance or replacement. Therefore, it is necessary to minimize pipe and shell damage during pipe installation and operation to ensure the service life of components. Compared to typical industrial centralizer systems that allow return pipes, current systems and methods provide a small additional cost to create engineered, custom or fit-for-purpose contact points to increase the envisioned life of the insulated return pipe.

Third, minimizing the flow resistance within the annular gap is an important design goal due to the need to maximize the power extracted. Unlike conventional drilling operations, which rationalize the use of large amounts of electricity in the pursuit of high-density hydrocarbons, energy losses in power generation should be minimized. Therefore, optimizing the slide for minimum flow resistance is an important feature for energy efficiency.

Finally, similar to the function of traditional centralizers, the slide allows the insulating return pipe to be positioned almost concentrically with the casing. Although perfect concentricity is not a requirement for the proper functioning of the insulated return pipe, the use of slides to create a separation distance between the insulated return pipe and the casing allows flow around the entire circumference of the casing, thus allowing the flow of water from the rock in all directions. Dissipate heat energy. In addition, the concentricity of the tubes and the relatively small flow disturbances caused by the multiple sliders help to ensure smooth flow of the heat transfer fluid, thereby preventing cavitation, vortex and/or wake erosion of the tubes.

In some embodiments, numbers indicate amounts of ingredients contained, and properties such as concentrations, reaction conditions, etc. used to describe and claim certain embodiments of the invention are to be understood in some instances by the term "about" grooming. Accordingly, in some embodiments, the various numerical parameters set forth in the written description and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by a particular embodiment. Recitation of multiple ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (eg, "such as") provided with respect to certain embodiments herein, may merely better illuminate the invention and do not pose a limitation on the scope of an otherwise claimed invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

As used in the description herein and the claims that follow, the meaning of "a" and "the" includes plural reference unless the context clearly dictates otherwise. Furthermore, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. As used herein, unless the context dictates otherwise, the term "coupled to" may include direct coupling (where two elements coupled to each other contact each other) and indirect coupling (where at least one additional element is located between the two elements) . Accordingly, the terms "coupled to" and "coupled with" may be used synonymously.

It will be apparent to those skilled in the art that many more modifications than those already described are possible without departing from the inventive concepts herein. Accordingly, the subject matter of the present invention is not to be restricted except within the scope of the appended claims. Furthermore, when interpreting the specification and claims, all terms should be interpreted in the broadest manner consistent with the context. In particular, the term "comprising" should be interpreted as indicating elements, components or steps in a non-exclusive manner, indicating that various elements, components or steps cited may exist, or be utilized, or be combined with other various elements, components or steps not explicitly cited. Combination of steps. When the specification or claim refers to at least one item selected from a combination consisting of A, B, C... and N, the text shall be interpreted as requiring only one element of that combination, not A plus N or B plus N Wait.

100: tubular pipe 112: inner wall 114: outer wall 116: insulating material 120A: Slider 120B: Slider 120C: Slider 212: inner wall 214: outer wall 216: insulating material 222: the second cladding material 224: The first backing material 226: Weld 230: tubular shell

Fig. 1 is an exemplary longitudinal schematic view along the central axis of a return pipe with a plurality of slides according to the subject matter of the present invention.

FIG. 2 is an exemplary cross-sectional schematic view of the return pipe shown in FIG. 1 .

FIG. 3 is a schematic side view of an exemplary return pipe shown in FIG. 1 .

Figure 4 depicts various configurations of exemplary sliders according to the inventive subject matter.

FIG. 5 is an exemplary perspective view of the return tube shown in FIG. 1 .

FIG. 6 is an exemplary longitudinal schematic view along the central axis of the return pipe shown in FIG. 1 in a tubular housing.

Fig. 7 is an exemplary schematic diagram of a plurality of return pipes shown in Fig. 6, which are arranged in a dry geothermal facility.

Figure 8 is a photograph showing an exemplary tubular casing for insulating material between the inner and outer surfaces of the tubular conduit to enclose the tubular conduit.

100: tubular pipe

112: inner wall

114: outer wall

116: insulating material

120A: Slider

120B: Slider

120C: Slider

Claims (29)

A tube assembly comprising: a tubular conduit having an inner surface and an outer surface, and a plurality of slides connected to the outer surface; wherein a first slide and a second slide have a longitudinal offset and a radial offset relative to each other relative to an imaginary central axis extending along a length of the tubular conduit; and Wherein, each of the sliders includes a first material and a second material, wherein the first material is connected to the outer surface of the tubular conduit, and wherein the second material forms an outer surface of the slider. The pipe assembly of claim 1, further comprising a third slide having an imaginary center relative to the first slide and the second slide and about extending along a length of the tubular conduit A longitudinal offset and a radial offset of the shaft. The pipe assembly of claim 1, wherein the tubular conduit includes an insulating material disposed between the inner surface and the outer surface. The pipe assembly of claim 1, wherein the plurality of slides are welded or otherwise permanently bonded to the outer surface of the tubular pipe. The tube assembly of claim 1, wherein the longitudinal offset between the first slide and the second slide is at least 30 inches. The tube assembly of claim 1, wherein the radial offset between the first slide and the second slide is at least 45 degrees. The tube assembly of claim 1, wherein the first material of the plurality of slides comprises steel. The tube assembly of claim 1, wherein the second material of the plurality of sliders comprises an alloy having a hardness less than the hardness of the first material. The tube assembly of claim 1, wherein the second material of the plurality of sliders has a lubricity greater than the lubricity of the first material. The tube assembly of claim 1, wherein the first material of the plurality of sliders is coated with the second material. The tube assembly as claimed in claim 1, wherein the first slider and the second slider have an elongated shape extending along an imaginary central axis and further have rounded end portions. The tube assembly of claim 1, wherein the first slide and the second slide have a thickness sufficient to force the tubular conduit to be off-center with respect to an imaginary central axis of a tubular housing surrounding the tubular conduit . 2. The pipe assembly of claim 1, wherein the tubular conduit has a strength sufficient to transport fluid at a pressure of at least 2,000 psi and a temperature of at least 250°F. The pipe assembly of claim 1, wherein the tubular pipe has a length of at least 2,000 meters. A pipe assembly comprising the pipe assembly of any one of claims 1 to 14, wherein a tubular housing surrounds the tubular pipe, and wherein the plurality of slides retain the outer surface of the tubular pipe and the A distance between an inner surface of a tubular shell. 15. The ducting assembly of claim 15, wherein the distance between the outer surface of the tubular duct and the inner surface of the tubular housing is between 0.25 inches and 1.50 inches. The ducting assembly of claim 15, wherein the tubular casing has an outer surface surrounded by grout. The pipe assembly as claimed in claim 15, wherein the tubular housing and the tubular pipe are connected to form a closed circuit for circulation of a working fluid. The pipeline assembly as claimed in claim 18, wherein the closed circuit further includes a heat exchanger and/or a generator. A geothermal device, comprising the pipeline assembly according to any one of claims 15-19. A slide for a tube-in-tube duct assembly comprising: a first material and a second material interconnected and arranged such that when installed in a space between two pipes in the pipe assembly, the first material contacts an outer surface of an inner pipe and the the second material contacts an inner surface of an outer pipe; Wherein, the slider has an elongated shape and has at least one rounded end portion; and Wherein, the elongated shape has an aspect ratio of at least 5:1. The slider of claim 21, wherein the slider has an aspect ratio of at least 1:1. The slider as claimed in claim 21, wherein the first material and the second material are coupled to each other through cladding. The slider of claim 21, wherein the first material comprises steel, and wherein the second material comprises copper and/or aluminum alloy. The slider of claim 21, wherein the elongated shape is between 8 and 16 inches in length. 21. The slider of claim 21, wherein the elongated profile has a width of between 1 and 2 inches. 21. The slider of claim 21, wherein the thickness of the elongated profile is between 0.5 and 1.0 inches. The slider as claimed in claim 21, wherein the elongated shape has side portions parallel to each other. The slider as claimed in claim 21, wherein the rounded end portion has a spherical or parabolic shape.

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