EP3828378B1 - Device and method for protecting deep boreholes against pressure - Google Patents

Description

The present invention relates to a device and a method for pressure protection of deep wells, in particular geothermal, oil, gas and/or cavern wells.

In the case of deep drilling, closed spaces can occur along the deep drilling. Such a space can be created, for example, in the form of an annular space between an inner and an outer casing of the deep well. In this case, media with a thermal expansion coefficient other than zero are present in these closed spaces. This includes fluids such as water. If the temperature in the closed space now changes, an increased pressure difference can arise between the closed space and its surroundings, since the closed space allows no or only a very small amount of outflow and also no or only a very small amount of expansion of the enclosed medium. This phenomenon is known in the art as "annular pressure build up" (APB) or as "trapped annular pressure" (TAP). The change in the temperature of the enclosed medium occurs, for example, when the temperature of the pumped medium in the deep well is high. The high temperature of the medium conveyed in the deep well is at least partially transferred to the closed space. The resulting change in the pressure difference can be so great that damage to the deep drilling occurs as a result.

Due to the structure of the deep drilling, the necessary casings and the necessary cementing processes, such closed spaces in deep drilling cannot be avoided or can only be avoided to a very limited extent. An example of such a deep hole can be found in document WO2012106028 being found.

In order to prevent such critical pressure differences and the damage associated therewith, it is known from the prior art to make the casing of the deep well more stable. This can be done by increasing the steel grade or by increasing the wall thickness of the casing so that the casing can withstand a higher pressure difference in the deep drilling. However, as a result of these measures, the available inner diameter of the deep well can be reduced, which can, for example, result in negative effects on a conveying rate of the conveyed medium of the deep well. In addition, a more stable design with higher manufacturing costs, the transport and installation of the piping. Furthermore, the theoretically necessary wall thicknesses may not be available or may be difficult to implement in practice.

Furthermore, in order to prevent impermissible pressure differences, it is known that the piping conveying a medium at an elevated temperature is thermally insulated in order to reduce a temperature increase in the adjacent closed spaces and thus to minimize the pressure increase. However, these solutions also lead to increased costs, longer installation times and are not practical for some types of deep drilling. Furthermore, the space available for deep drilling is usually limited, so that insulation cannot be provided or can only be provided to a very limited extent.

Another attempt to prevent an unacceptable pressure difference is made by creating a connection between the enclosed spaces and the environment. However, this weakens the casing and intentionally destroys the barrier provided by the casing. Furthermore, it is known to create a connection between the closed spaces and the surface of the earth or a seabed. However, this is only possible with tubing or tubing sections that are routed to the surface of the earth or to the seabed.

It is also known to introduce pressure-compensating materials such as foams in a targeted manner in order to equalize the pressure in the closed spaces in the areas in which closed spaces can arise. These then enable a targeted expansion of the media expanding in the closed rooms. However, such methods are very cost-intensive and require precise calculations and investigations beforehand for the design. In addition, the installation is very time-consuming and expensive.

In addition, it is well known in the art to provide mechanical components in areas where confined spaces may arise. These mechanical components can open and allow the enclosed medium to expand in a targeted manner by escaping into other areas. However, previously known solutions are very complex, expensive and also require precise calculation beforehand for the design of the mechanical components.

There is consequently a need for solutions that address the problem of confined spaces along deep wells. It is therefore the object of the present invention to solve at least some of the problems known from the prior art described above and to provide an improved solution for dealing with media located in closed rooms and the risks associated therewith.

The object according to the invention is achieved by a device for pressure protection of deep bores according to patent claim 1. Furthermore, the object according to the invention is achieved by a method for pressure protection of deep wells according to patent claim 19. Advantageous developments of the invention are described in the dependent patent claims.

The above-mentioned object is achieved according to claim 1 by a device for pressure protection of deep wells, in particular geothermal, oil, gas and/or cavern wells. The device comprises at least one receiving body which is designed to receive a compressible medium in an interior space. The receiving body has at least one opening, which forms a transition between the interior and an area surrounding the receiving body. The at least one opening can be closed with at least one closure element and is arranged in the opening assigned to it. The closure element is also designed to assume an open and a closed state depending on a predetermined pressure difference between the interior and the environment. The receiving body is formed at least in sections by a coiled tubular element, with the coiled tubular element being embodied in a helical shape.

Advantageously, the device according to the invention makes it possible to prevent impermissible pressure differences. Furthermore, the device according to the invention provides a simple receiving body for pressure protection. The receiving body can be configured as required. Tubular elements are available on the market with different properties such as diameters, material and strength and can therefore be selected in a wide variety of designs for the intended use. Such tubular elements can be standardized according to DIN, ISO or ASME. Standardized tubes can be used as tube elements. If necessary, these can be adjusted later and, for example, brought into the required twisted shape or length.

The wide availability of pipe elements on the market also leads to comparatively low procurement costs. In addition, pressure vessels with a round shape, such as pipe elements, are particularly robust with regard to pressure differences between the interior of a pipe and the environment. Furthermore, the length of the tube elements used can be adjusted depending on the required size of the receiving body. The size of the receiving body is therefore very variable. The scope of the pressure protection can thus be adjusted.

The coiled shape of the tubular elements allows the at least one receiving body to be adapted to existing geometries. Thus, the convoluted shape can take into account an existing shape of the deep hole, for example a tube of the deep hole. For example, the coiled tubing member may at least partially wrap a tube of the downhole around its circumference. Furthermore, it can be guided along an existing pipe of the deep bore in the longitudinal direction. In addition, the convoluted shape enables a narrow design of the device according to the invention, which is based on the spatial conditions available.

The absorbable compressible medium, for example air or an inert gas, makes it possible to be compressed when the pressure rises, which occurs, for example, when another medium flows into the absorbing body according to the invention. The compressible medium serves as a kind of buffer that at least partially compensates for an increase in pressure with additional volume. Furthermore, the compressible medium can be specifically selected in advance depending on its properties and the existing requirement.

The closure element makes it possible to secure the pressure in the deep well as a function of a predetermined pressure difference. The predetermined pressure difference at which the closure element assumes the closed or the open state can thus be adjusted as required. This can prevent the pressure from being secured even if the pressure difference is too low, i. h the locking element opens too early. Furthermore, it can be achieved that the compressible medium does not escape from the at least one receiving body in advance, for example during installation of the device according to the invention at its place of use, and is replaced by a less compressible or even incompressible medium that would limit or prevent the pressure protection. If the closure element assumes the open state, a pressurized medium can flow from the surroundings of the receiving body into the receiving body expand. The pressure in the receiving body can increase and the compressible medium can be compressed. However, the pressure in the vicinity of the accommodating body can also be reduced. This can prevent impermissibly high pressures from occurring during deep drilling. Furthermore, the closure element makes it possible to adjust the device according to the invention directly at the place of use, for example on a surface of the deep bore before assembly. Provision can be made for the closure element to be connected to the receiving body via a thread, for example, so that different closure elements can be optionally screwed in.

The device according to the invention also allows it to be manufactured and assembled remotely from its place of use and then to be adapted and installed on site. For example, spatial restrictions at the place of use can be circumvented.

The small number of individual components of the device according to the invention enables a low susceptibility to errors. Furthermore, the assembly effort in the factory and on site can be reduced.

According to a development of the invention, it can be provided that the at least one receiving body is made of metal, in particular steel. The receiving body can also be made of a plastic or a composite material. Furthermore, it can be provided that the at least one closure element is made of metal, in particular steel, plastic, ceramic, glass, a composite material or a combination of materials. In addition, different areas of the closure element can be made of a different material suitable for the application. The materials of the receiving body and of the closure element can thus advantageously be selected for the intended use.

According to the invention, it is provided that the coiled tubular element is embodied in a helical shape.

This geometric shape makes it possible to adapt the tubular element to existing geometries of a deep hole. Furthermore, a receiving body can be formed which is continuous extends. The length can be adjusted as required. Existing rooms can be used efficiently.

If the coiled tubular element is helical, it can, for example, wind around another element. Furthermore, the gradient of the helix course is freely adjustable. In other words, the number of turns of the coiled tube element is freely adjustable in relation to a length extension of the helical shape. A helical shape is understood to be a shape similar to a helix, a cylindrical spiral or a helix.

A development of the invention provides that two or more receiving bodies are arranged adjacent to one another, in particular in a radial direction of the depth bore. It can be provided that a coiled tubular element of an outer receiving body encompasses a coiled tubular element of an inner receiving body. It is thus possible to increase the number of receiving bodies in a deep borehole. In addition, available space in a deep drilling can be used efficiently. Overall, the ability to pressure secure the deep well is improved.

According to one aspect of the invention it can be provided that the tubular element is wound in such a way that adjacent windings are arranged at a distance from one another or abut one another. If adjacent windings are arranged adjacent to one another, the available space can be used efficiently. If adjacent windings are arranged at a distance from one another, space can be provided in a targeted manner that can be used, for example, for other purposes. For example, access to a wound element may be provided by the objected arrangement. The tube element itself can possibly consist of a flexibly expandable material, at least in sections.

A further development of the invention provides that the receiving body is designed to wind around an inner casing arranged in the depth bore and/or to be received in an outer casing. If the receiving body winds around an inner tubing, the device for pressure protection can protect the pressure outside of this inner tubing. Accordingly, the pressure-protection device can protect the pressure inside an external piping when it is accommodated therein.

According to an aspect of the invention, the receiving body is adapted to be arranged in a space between the inner casing and the outer casing. In this way, the pressure in the intermediate space can be safeguarded with the device according to the invention. The coiled tube element can be adapted to the existing geometry of the gap.

In addition, it can be provided that the at least one closure element has a predetermined breaking point. The predetermined breaking point can be designed in such a way that it breaks in a predetermined manner. The predetermined breaking point of the closure element can thus advantageously break at a predetermined pressure difference. The predetermined pressure difference can be a value below a critical pressure difference. Thus, the pressure equalization can advantageously already take place before a critical pressure arises and the deep drilling, in particular one of the casings, would be damaged. Furthermore, such refractive elements can be inexpensive to manufacture and simple to install and replace in the field.

A development of the invention provides that the at least one closure element is a valve, a pressure-adjustable pressure valve, a bursting disk or a bursting plug. The valve makes it possible to fill the receiving body with a compressible medium in advance and thus a certain amount of the compressible Provide medium in the receiving body. Furthermore, the valve makes it possible to apply a specific pressure to the compressible medium in the receiving body beforehand. The pressure-adjustable pressure valve makes it possible to variably set the pressure at which the valve opens and closes. For this purpose, the pressure-adjustable pressure valve can have a spring whose spring force can be adjusted. The bursting disc and the bursting plug irreversibly change state in contrast to the valve and the pressure-adjustable pressure valve. So if the bursting disc or bursting plug breaks, the closure element is permanently open.

According to one aspect of the invention, it can be provided that the compressible medium comprises a fluid. In a preferred aspect, the compressible medium is a compressible gas, a compressible liquid, or a combination thereof. For example, the fluid may include air, nitrogen, other compressible media, or a mixture thereof. Fluids have the advantage that they adapt to existing geometries and at least partially fill them. They can also be supplied via hose systems. A gas usually has the advantage of being more compressible than a solid or liquid, while at the same time having a lower density.

According to a development of the invention, it can be provided that the thermal expansion coefficient of the compressible medium in the interior is lower than the thermal expansion coefficient of a medium surrounding the device according to the invention. For example, if the device according to the invention with the compressible medium contained therein and the medium surrounding the device according to the invention heat up, it can be ensured that the pressure of the compressible medium in the interior increases less than the pressure of the surrounding medium.

Furthermore, it can be provided that the receiving body can be fixed in the deep bore with at least one fixing arrangement. It is thus advantageously possible to arrange the receiving body at a predetermined position in the deep bore. Furthermore, it is possible to arrange several receiving bodies at different points of the deep bore. In this way, receiving bodies can be arranged in a targeted manner and as required at different distances from the depth bore. Furthermore, the fixing arrangement can have a protective effect on the receiving body, so that damage to the receiving body can be prevented.

According to a further development, it can be provided that the at least one fixing arrangement can be fixed relative to the inner piping and/or the outer piping. The device according to the invention can thus be arranged flexibly.

In addition, it can be provided that the at least one fixing arrangement prevents an axial movement of the receiving body along the inner casing and/or outer casing.

According to one embodiment of the invention, it can be provided that a receiving body is fixed in the deep bore with two fixing arrangements. The two fixing arrangements can thus be arranged on different sides of the receiving body. A fixing arrangement can be arranged on an underside of the receiving body, while the other fixing arrangement is arranged on an upper side of the receiving body. The fixing arrangement on the underside of the receiving body can prevent the receiving body from slipping further into the deep bore. The fixing arrangement on the upper side of the receiving body can also prevent the receiving body from slipping out of the deep bore, for example due to buoyancy forces.

According to one aspect it can be provided that the fixing arrangement is clamped in relation to the inner piping and/or outer piping. Jamming has the advantage of preventing damage to the inner tubing and/or outer tubing. At the same time, reliable fixation is made possible. In this way, sensitive piping can be protected and weak points in the internal piping and/or external piping can be prevented.

Furthermore, according to a further development it can be provided that the fixing arrangement comprises at least one screw. This can be bolted against the inner tubing and/or outer tubing. Screws provide a flexible means to releasably secure the fixture assembly. Furthermore, a large number of screws can be provided in order to fix the fixing arrangement. A force distribution and a force introduction into the inner tubing and/or outer tubing can thus be distributed over the multiplicity of screws. Furthermore, the effect of an incorrect fastening of a single screw on the fixation of the fixation arrangement is also reduced.

According to one aspect it can be provided that the at least one screw is designed as a stud screw. This can be bolted against the inner tubing and/or outer tubing.

Provision can furthermore be made for the fixing arrangement to have a fixing ring which is thicker in the radial direction than the receiving body. This can bring about a protective effect against the receiving body. If the receiving body is arranged at a specific position in the deep borehole, the fixing ring first collides with surrounding elements such as the inner casing and/or outer casing. As a result, damage to the receiving body during on-site installation or assembly can be at least reduced or prevented.

According to a development, the fixing ring can be designed in such a way that it at least partially fills an annular space between the inner tubing and the outer tubing. This is particularly advantageous when a fixation relative to the inner or outer piping is provided.

According to one aspect, the fixing ring can be designed in such a way that it does not completely fill the annular gap between the inner casing and the outer casing in the radial direction at least in sections along its circumference. This allows for increased circulation of media in the space. For example, this can be advantageous for cementation processes or a more homogeneous distribution of a medium in the intermediate space.

According to one aspect of the invention, it can be provided that the fixing ring is designed with a variable wall thickness in the radial direction. This is particularly advantageous when increased circulation is desired in the space between the inner casing and the outer casing. For example, this can be advantageous for cementation processes or a more homogeneous distribution of a medium in the intermediate space.

Furthermore, it can be provided that the fixing ring has ribs with clearances arranged between them, with the ribs being formed larger in the radial direction than the clearances. The ribs can be arranged on the outside of the fixing ring. The at least one screw of the fixing arrangement can be arranged in one of the clearances. It can extend in the radial direction for fixation.

According to one embodiment, it can be provided that the fixing ring is made of metal, in particular steel. Furthermore, the fixing ring can be formed from a plastic such as a synthetic resin or from a cement-based material or a composite material. The fixation ring can be a cast part, a turned part, a milled part, a 3D printed part or a combination.

A further development of the invention provides that the receiving body comprises a number of different closure elements. This enables a flexible configuration of the device according to the invention. For example, a valve can be provided to apply a predetermined pressure to the receiving body. This can already take place during installation or assembly. A pressure-adjustable pressure relief valve, bursting disc, or bursting plug may be provided to assume the open and closed states for pressure relief at a later time. Furthermore, multiple closure elements increase the reliability of pressure protection.

Furthermore, it can be provided that the different closure elements assume the open and closed state when there is a different pressure difference between the interior space and the environment. This can allow for staggered pressure hedging.

According to a further development, the receiving body comprises a number of sections which are separated from one another by closure elements. This can allow for staggered pressure hedging. The device according to the invention can be flexibly adapted to circumstances.

According to one aspect of the present invention, the plurality of closure elements can be configured to assume the open and closed states when there is a different pressure difference between the adjacent sections. This can allow for staggered pressure hedging.

According to one configuration, the device comprises a plurality of receiving bodies. In this way, the scope of the pressure protection can be adapted to the existing conditions. Furthermore, the reliability can be increased. The multiple receiving bodies can have different closure elements. This enables a flexible configuration of the device according to the invention.

If the device comprises a plurality of receptacle bodies, it can be provided that the plurality of receptacle bodies assume the open and closed state when there is a different pressure difference between the respective interior space and the environment. In this way it can be achieved that the receiving bodies provide pressure protection in the event of a different pressure difference. Furthermore, this can enable a staggered pressure protection.

Furthermore, the object on which the invention is based, which was described at the outset, is achieved by a method for pressure protection of deep wells, in particular geothermal, oil, gas and/or cavern wells. The method is preferably carried out using a device of the type described above. At least one receiving body is designed to receive a compressible medium in an interior space. In addition, at least one closure element is designed to assume an open and a closed state depending on a predetermined pressure difference between the interior of the receiving body and an environment. The method comprises the step of subjecting the receiving body to a predetermined pressure, the step of arranging the receiving body in the deep borehole and the step of equalizing a pressure difference between the interior and the surroundings of the receiving body, with the closure element at least temporarily assuming an open state.

The method according to the invention enables a simple solution for pressure protection in deep drilling. Furthermore, the method according to the invention can be flexibly adapted and is therefore advantageous for different types of deep drilling.

The loading of the receiving body with a predetermined pressure makes it possible to adapt the receiving body for its intended use and to modify it according to the requirements. It can be provided that a compressible medium is filled into the receiving body.

The step of arranging the accommodating body in the deep bore makes it clear that the accommodating body can first be manufactured and modified remotely from its place of use and finally installed and arranged at the place of use. In this way, for example, spatial restrictions at the place of use can be circumvented, which would not allow or only to a limited extent to modify the receiving body, such as for example subjecting the receiving body to a predetermined pressure.

The pressure equalization described above ensures that the deep drilling is protected against pressure. It enables critically high pressures in the vicinity of the device according to the invention to be reduced and/or prevented. In this way, damage to the deep borehole, in particular to the pipes used, can be avoided as a result of critically high pressure, in particular in the vicinity of a pipe, such as in an intermediate space or an annular space. In addition to the immediate vicinity of the device according to the invention, the pressure equalization can also have a positive effect on areas of the deep well that are further away, since the pressure can also drop there depending on the structure of the surroundings. The effective range can therefore be larger than the direct surroundings of the device according to the invention.

The method according to the invention is easy to carry out. It also offers the possibility of being adapted to the prevailing conditions. Furthermore, the receiving body and/or the closure element used in the method can be adapted to the circumstances.

A development of the method according to the invention provides that a medium flows into the receiving body during the pressure equalization. In this way, an additional expansion volume can be generated. The pressure of the inflowing medium can be reduced as a result.

According to one aspect of the method according to the invention, it can be provided that a compressible medium in the interior of the receiving body changes its volume during the pressure equalization. The change in volume can bring about a reduced pressure in the area surrounding the device according to the invention. In this way, an impermissibly high pressure in the area can be prevented.

According to a development of the method according to the invention, it can be provided that the at least one closure element assumes a permanently open state during pressure equalization. It can be an irreversibly actuatable closure element.

One embodiment of the method according to the invention provides that the closure element assumes an open state above the predetermined differential pressure and a closed state below the predetermined differential pressure. It can be a reversibly operable closure element.

It is clear to the person skilled in the art that features, properties and advantages of the invention which have been explained in connection with the device according to the invention also apply to the method according to the invention. The reverse of this is also clear to a person skilled in the art.

Fig. 1

eine schematische Schnittansicht einer Tiefenbohrung, die die erfindungsgemäße Vorrichtung umfasst;

Fig. 2

eine schematische Detailansicht einer Ausführungsvariante der erfindungsgemäßen Vorrichtung in der Tiefenbohrung;

Fig. 3

eine schematische Detailansicht einer Ausführungsvariante einer erfindungsgemäßen Fixieranordnung, angeordnet in der Tiefenbohrung;

Fig. 4

eine schematische Seitenansicht eines erfindungsgemäßen Aufnahmekörpers;

Fig. 5

eine schematische dreidimensionale Seitenansicht des erfindungsgemäßen Aufnahmekörpers;

Fig. 6

eine schematische Explosionszeichnung einer erfindungsgemäßen Fixieranordnung;

Fig. 7

eine schematische Detailansicht einer erfindungsgemäßen Fixieranordnung angeordnet in einer Tiefenbohrung;

Fig. 8

eine schematische Detailansicht einer erfindungsgemäßen Fixieranordnung mit Stiftschrauben;

Fig. 9

eine schematische Detailansicht einer Öffnung des Aufnahmekörpers mit Verschlusselement;

Fig. 10

eine schematische Schnittansicht durch ein Verschlusselement an dem Aufnahmekörper der erfindungsgemäßen Vorrichtung;

Fig. 11

eine schematische Ansicht einer erfindungsgemäßen Vorrichtung mit mäanderförmig gewundenem Rohrelement; und

Fig. 12

eine schematische Ansicht einer erfindungsgemäßen Vorrichtung mit spiralförmig gewundenem Rohrelement.

The invention is explained below by way of example with reference to the accompanying figures. They represent:

1

a schematic sectional view of a deep well comprising the device according to the invention;

2

a schematic detailed view of an embodiment of the device according to the invention in the deep well;

3

a schematic detailed view of an embodiment of a fixing arrangement according to the invention, arranged in the depth bore;

4

a schematic side view of a receiving body according to the invention;

figure 5

a schematic three-dimensional side view of the receiving body according to the invention;

6

a schematic exploded view of a fixing arrangement according to the invention;

7

a schematic detailed view of a fixing arrangement according to the invention arranged in a deep bore;

8

a schematic detailed view of a fixing arrangement according to the invention with studs;

9

a schematic detailed view of an opening of the receiving body with closure element;

10

a schematic sectional view through a closure element on the receiving body of the device according to the invention;

11

a schematic view of a device according to the invention with a meandering coiled tubular element; and

12

a schematic view of a device according to the invention with a spirally wound tubular element.

figure 1 shows a schematic sectional view of a deep well 10, which includes a multiplicity of devices 12 according to the invention for pressure protection. The deep borehole 10 runs to the ground surface 14 and extends into the ground 16 in several sections, the diameter of the deep borehole 10 being smaller the further the deep borehole 10 extends into the ground 16 . The deep borehole 10 is designed to be essentially axisymmetric to a borehole axis A. At the surface 14 is a borehole wall 18. The borehole wall 18 may include cementing 20. Within the borehole wall 18, ie with a smaller diameter, a standpipe 22 is arranged in the length of the depth extent of the borehole wall 18. Inside the standpipe 22 there is a casing, referred to below as the casing 24 , with a smaller diameter compared to the location 22 . The casing 24 has a greater depth extension than the standpipe 22. The standpipe 22 and the casing 24 can be made of steel. A cementing 20 is also arranged in a space between the standpipe 22 and the casing 24 , lining the space and extending over the entire length of the casing 24 . With a smaller diameter than the casing 24 , an anchorage referred to as a tieback 26 is formed within the casing 24 . The tieback 26 borders on the production hole 28 of the deep well 10 . A first fluid 30 and a device 12 according to the invention are located between the casing 24 and the tieback 26.

A lower area of the tieback 26 adjoins a first production liner 32 . Outside of the first production liner 32 , cementing 20 is also formed in a lower area, which forms a transition to the ground 16 . In the radial direction on the inside, the first production liner 32 forms a transition to the borehole 28. No cementation is formed in an upper area of the first production liner 32, but rather in a transition area 33, in which the length of the first production liner 32 and the casing 24 overlap. a second fluid 34 and one of the devices 12 according to the invention are arranged. The second fluid 34 may be free water after a cementation process.

Above the second fluid 34 in the transition region 33 between the tieback 26 and the first production liner 32 in the radial extension to the casing 24 is a first Separating element 36 is arranged, which separates the first fluid 30 from the second fluid 34 . The first separator 36 may be what is known in the art as a top liner hanger packer.

A second production liner 38 is arranged further inside the borehole 28 opposite the first production liner 32 with a smaller diameter and at a distance from it. A second separating element 40 and a third separating element 42 are arranged in an intermediate space 39 between the first production liner 32 and the second production liner 38 . The second separating element 40 closes off the intermediate space 39 between the first production liner 32 and the second production liner 38 at the top, ie oriented in the direction of the earth's surface 14, towards the borehole. The third separating element 42 is also arranged below the second separating element 40 in the intermediate space 39 between the first production liner 32 and the second production liner 38 and divides a non-cemented area into two sub-areas, in each of which a device 12 according to the invention is arranged. Each of the sub-regions is at least partially filled with the second fluid 34 . In a region of the second production liner 38 arranged further down in the deep well 10 , cementing 20 is also formed on the outside of the second production liner 38 , which extends to a lower end of the second production liner. The top of the cementation 20 is substantially coincident with the bottom of the first production liner 32 .

In the deepest area of the deep well 10, a perforated tubular element 44 adjoins an inner area of the second production liner 38, which is perforated opposite the conveyor hole 28 and extends deeper into the borehole 28 than the second production liner 38.

figure 2 shows a schematic detailed view of an embodiment variant of the device 12 according to the invention in the deep borehole 10. The schematic detailed view according to FIG figure 2 is a partial section through the deep hole 10 according to figure 1 at the level of the M mark.

figure 2 shows the device 12 according to the invention with a receiving body 46. The receiving body 46 is formed by a coiled, helical tubular element 48. FIG. The coiled tubing member 48 includes a plurality of coils which abut one another and surround an inner tubing 50 . Outboard of the coiled tubing member 48 is outer tubing 52 .

Regarding figure 1 the inner casing 50 corresponds to the second production liner 38 and the outer casing 42 to the first production liner 32. Outside the outer casing 52 a cementation 20 is formed. The wall thickness of the cementation 20 is pronounced to different extents in the longitudinal extent of the deep borehole 10 . The soil 16 adjoins the cementing 20 .

The coiled tube element 48 is hollow inside. A first opening 54 is formed at one end of the coiled tubing member 48 and a second opening 56 is formed at the other end of the coiled tubing member 48 . A first closure element 58 is arranged in the first opening 54 and a second closure element 60 is arranged in the second opening 56 .

A first fixing arrangement 62 is arranged at one end of the receiving body 46 and a second fixing arrangement 64 is arranged at the other end of the receiving body 46 . The two fixing arrangements 62, 64 each have a fixing ring 63, 65. The fixing rings 63, 65 enclose the inner casing 50 and are surrounded by the outer casing 52. The fixing rings 63, 65 are of essentially the same design, but one fixing ring 63 is rotated by 180 degrees relative to the other fixing ring 65, so that the same sides are arranged relative to the receiving body 46.

The configuration of the fixing arrangements 62, 64 in relation to the second fixing arrangement 64 is briefly presented below. The second fixing ring 65 includes a plurality of ribs 66. The ribs 66 are evenly distributed in the circumferential direction of the second fixing ring 65 and extend outward in the radial direction of the fixing ring 65. The ribs 66 extend in the longitudinal direction of the fixing ring 65 and thus also in the longitudinal direction of the deep bore 10 and the receiving body 46. A respective clearance 68 is formed between two ribs 66. The ribs 66 are designed to be larger in the radial direction than the clearances 68. A plurality of screws 70, which are designed as stud bolts, are arranged in each of the respective clearances 68. The clearances 68 are never in contact with the outer casing 52 due to their smaller lateral extent. If the ribs 66 are in contact with the outer casing and the fixing ring 65 encloses the inner casing 50, free space still remains through the clearances 68, which can enable a simple cementing process. Furthermore, media surrounding the fixing ring 65 can circulate freely.

figure 3 shows a schematic detailed view of an embodiment variant of the device 12 according to the invention, arranged in the deep bore 10, in a section along the marking M of FIG figure 1 . The device 12 according to the invention is arranged in the intermediate space 39 between the inner casing 50 and the outer casing 52 . In the representation according to figure 3 only a portion of the receptacle body 46 with a portion of the coiled tubing member 48 is shown. The first closure element 58 is arranged at the first opening 54 .

The first fixing arrangement 62 is likewise arranged in the intermediate space 39 above the receiving body 46 . The fixing ring 63 of the first fixing arrangement 62 extends in the radial direction over the entire intermediate space 39 and touches the inner piping 50 . The fixing ring 63 is fixed to the inner piping 50 . The representation according to figure 3 is not true to scale, in fact the fixing ring 63 is spaced from the outer casing 52. It is also possible that the fixing ring 63 touches the outer piping 52 . This is the case in particular when the fixing ring 63 is fixed to the outer casing 52 . The second fluid 32 is located in the remaining space 39 shown.

Outside of the outer casing 52 the cementation 20 is formed, which forms a transition to the ground 16 . As already in connection with figure 2 explained, the wall thickness of the cementation 20 in the longitudinal direction of the deep borehole 10 is designed to have different strengths.

A compressible medium 72 is located in the coiled tube element 48. The compressible medium 72 is not shown in detail, but includes, for example, air, nitrogen, other compressible media or a mixture thereof.

figure 4 12 is a schematic side view of the containment body 46 formed by the coiled tubing member 48 in accordance with the present invention. It can be seen that the turns of the tubular member 48 abut one another. Tubular member 48 is helically wound about borehole axis A at a constant radius. The first opening 54 of the coiled tubing member 48 is in figure 4 not visible. In the illustration shown, the first opening 54 is formed on the rear side of the receiving body 46 . The second opening 56 of the coiled tubing 48 is formed on another side of the coiled tubing 48, which is the lower side as viewed. The second closure element 60 is arranged in the second opening 56 .

figure 5 12 is a schematic three-dimensional side view of the receiving body 46 according to the invention. The second closure element 60 is designed as a bursting plug. The first opening 54 is shown in FIG figure 5 not visible because it is formed on the back of the receiving body 46 in the illustration shown.

It can also be seen in this illustration that the tubular element 48 is wound helically around the borehole axis A with a constant radius. Further, the turns of the coiled tubing member 48 abut one another.

figure 6 is a schematic exploded drawing of a fixing arrangement 62, 64 according to the invention. The fixing ring 63, 65 comprises the plurality of ribs 66 which are distributed evenly in the circumferential direction of the fixing ring 63, 65 and extend outwards in the radial direction. The clearances 68 are formed between the ribs 66 . A multiplicity of threads 74 are formed in the clearances 68 and extend in the radial direction of the fixing ring. The screws 70 shown floating in the exploded drawing are designed in such a way that they can be screwed into the threads 74 in the clearances 68 of the fixing ring 63, 65. The screws 70 are designed as studs.

A circumferential surface 76 of the fixing ring 63, 65 that is on the inside in the radial direction is essentially flat. The inner peripheral surface 76 is at each point to the longitudinal axis of the fixing ring 63, 65 equally spaced. An outer peripheral surface 78 of the fixing ring 63, 65 is not flat, as explained, but includes the ribs 66 and the clearances 68.

In the illustration shown, the fixing ring 63 , 65 has a chamfer 80 which extends in the circumferential direction and is arranged between a front side of the fixing ring 63 , 65 and the outer circumferential surface 78 . Such a chamfer 80 can also be formed on the rear side of the fixing ring 63, 65. In the illustration shown, however, no such chamfer 80 is formed on the rear side of the fixing ring 63, 65.

figure 7 is a schematic detailed view of a fixing arrangement 62, 64 according to the invention arranged in a deep well 10. The fixing arrangement 62, 64 is arranged between the inner casing 50 and the outer casing 52. The inner casing 50 is substantially opposite the borehole axis A centered. Accordingly, the fixture assembly 62, 64 and outer casing 52 is also substantially centered about the borehole axis A. The ribs 66 of the fixing ring 63, 65 rest against the outer tubing 52. The inner peripheral surface of the fixing ring 63, 65 rests against the inner tubing 50. FIG. As can be seen from the illustration, the clearances 68 form a free passage between the fixing ring 63, 65 and the outer casing 52. The respective transitions between the clearances 68 and the ribs 66 are not designed with sharp edges, but radii form a smooth transition .

figure 8 is a schematic detailed view of a fixing arrangement 62, 64 according to the invention with screws 70 in section. The fixture assembly 62, 64 is positioned within the downhole well 10 and disposed between the outer casing 52 and inner casing 50. As shown in FIG. The section through the fixing arrangement 62, 64 is shown in FIG figure 7 along line BB. Accordingly, one of the clearances 68 is cut through the cut.

As shown in the illustration, the fixing ring 63, 65 is fixed relative to the inner tubing 50. This is brought about by the screws 70 of the fixing ring 63 , 65 being screwed into the fixing ring 63 , 65 in the direction of the inner casing 50 and a front face of the screws 70 being pressed against the inner casing 50 . This creates a clamping force that prevents the fixing ring 63 , 65 from slipping or twisting relative to the inner tubing 50 .

The number of screws 70 can be selected almost arbitrarily, but a minimum clamping force is required so that no slipping or twisting takes place. A higher number of bolts 70 results in a better distribution of the forces applied by the bolts 70 to the inner casing 50 since a single bolt 70 then has to apply a lower clamping force and at the same time the individual clamping forces are distributed over a larger area of the inner casing 50 .

figure 9 shows a schematic detailed view of an opening 54, 56 of the receiving body 46 with closure element 58, 60. More precisely, in FIG figure 9 a detail out figure 4 shown in a front view, namely the second opening 56 with the second closure element 60. It can be seen that the second closure element 60 is arranged inside the coiled tube element 48 and the second opening 56 closes.

figure 10 shows a schematic sectional view through the closure element 60 on the receiving body 46 of the device 12 according to the invention figure 9 shown in section along line CC. The closure element 60 is arranged at the opening 56 of the receiving body 46 . In the illustration shown, the closure element 60 is designed as a bursting plug which comprises an end cap 82 , a pipe socket 84 and a bursting plug element 86 . The end cap 82 is attached to an end face of the opening 56 of the receiving body 46 . The pipe socket 84 is arranged on an inside of the end cap 82 . The outside of the pipe socket 84 bears against the inner circumference of the end cap 82 and its end face partially touches the end face of the opening 56. The rupture plug element 86 is arranged inside the pipe socket 84. It is connected to the pipe socket 84.

A rupturable element 88 is arranged in the bursting plug element 86, which ruptures above a permissible differential pressure between the inner area of the receiving body 46 and the other side of the rupturable element 88 on an outer side of the receiving body. For this purpose, the rupturable element 88 can be designed with a predetermined breaking point. The rupturable element 88 can be made of ceramic or a metal, for example.

The coiled tubing member 48, end cap 82, tube stub 84 and rupture plug member 86 may be formed of a weldable metallic material and welded together. Furthermore, they can be connected to one another by other suitable types of connection such as gluing or by means of threads.

In the illustration shown, the pipe socket 84 is welded to the end cap 82 . A thread is formed on the inside of the pipe socket 84, which thread can be attached subsequently, into which the rupture plug element 86 is screwed. End cap 82 is shown welded to coiled tubing 48 .

The closure element 60 off figure 10 and its location relative to the coiled tubing member 48 is for exemplary purposes only. The closure element 60 can also be designed differently and thus, for example, be arranged completely within the opening 56 of the receiving body 46 .

figure 11 shows a schematic view of a device 12 according to the invention with a meanderingly wound tubular element 148. The shown wound tubular element 148 of the receiving body 146 comprises essentially straight sections and/or slightly curved sections which are connected to one another with curved sections. The compressible medium 72 is located inside the meanderingly wound tubular element 148 . The device 12 shown comprises two closure elements 58 , 60 which are arranged in respective openings 54 , 56 .

The length of the coiled tubular element 148, the number of curved sections and the spacing of the straight sections can be adapted to the requirements of a deep well 10 in almost any way. Thus, the coiled tube element can be formed similar to a mat. If required by the geometry of the place of use, provision can be made for the coiled tubular element 148 to be bent further, for example about an axis which lies in the plane of the drawing.

figure 12 shows a schematic view of a device 12 according to the invention with a receiving body 246 with a spirally wound tubular element 248. The spirally wound tubular element 248 is not shown in section in the illustration shown. The device 12 comprises two closure elements 58, 60 which are arranged in respective openings 54, 56 which are not shown in detail.

For the use of a device 12 according to the invention for pressure protection of a deep well, the desired shape of the one or more receiving bodies 46, 146, 246 can be selected in a first step.

Furthermore, the at least one receiving body 46, 146, 246 is formed from corresponding coiled tubular elements 48, 148, 248. The individual components of the receiving body 46, 146, 246 can be connected to one another using suitable connecting means.

In addition, the appropriate at least one closure element 58, 60 is selected for use and arranged in the receiving body 46, 146, 246.

The receiving body 46, 146, 246 is also filled with a compressible medium 72. In addition, the receiving body 46, 146, 246 can now be subjected to a predetermined pressure.

In a further step, the receiving body 46 , 146 , 246 is now arranged in the deep bore 10 . For this purpose, the receiving body 46, 146, 246 can be fixed in the deep bore 10 with the at least one fixing arrangement 62, 64. The fixing can be easily performed by tightening the screws 70, for example.

If the pressure outside of the receiving body 46, 146, 246 according to the invention now increases and exceeds a predetermined pressure of the at least one closure element 58, 60, the closure element 58, 60 opens and the medium surrounding the receiving body 46, 146, 246 according to the invention can flow into the receiving body 46, 146, 246 flow in. In doing so, it displaces and compresses the compressible medium 72 in the receiving body 46, 146, 246. The pressure in the vicinity of the receiving body 46, 146, 246 can be reduced, particularly in the vicinity of the opened closure element 58, 60.

This process can be reversible, i. H. it can be repeated or it occurs once. The receiving body can also be designed in such a way that it can be used several times or only once.

Claims (14)

1. A device (12) for protecting deep wells (10) from pressure, in particular geothermal, oil, gas and/or cavern wells, the device (12) comprising at least one receiving body (46, 146, 246) configured to receive a compressible medium (72) in an interior space, the receiving body (46, 146, 246) having:

   at least one opening (54, 56) forming a transition between the interior space and an environment of the receiving body (46, 146, 246),

   wherein the at least one opening (54, 56) is closable by means of at least one closure member (58, 60) disposed in the opening (54, 56) assigned thereto and configured to assume an open and a closed state as a function of a predetermined pressure difference between the interior space and the environment,

   characterized in that

   the receiving body (46, 146, 246) is formed, at least in sections, by a coiled tubular member (48, 148, 248), the coiled tubular member (48, 148, 248) having a helical shape.
2. The device (12) of claim 1, characterized in that the tubular member (48, 148, 248) is coiled such that adjacent coils are spaced apart or abut one another.
3. The device (12) of any one of the preceding claims, characterized in that the receiving body (46, 146, 246) is configured to wrap around an inner casing (50) arranged in the deep well (10) and/or to be received in an outer casing (52), preferably to be arranged in a space (39) between the inner casing (50) and the outer casing (52).
4. The device (12) of any one of the preceding claims, characterized in that the at least one closure member (58, 60) has a predetermined breaking point.
5. The device (12) of any one of the preceding claims, characterized in that the at least one closure member (58, 60) is a valve, a pressure-adjustable pressure valve, a bursting disk or a bursting plug.
6. The device (12) of any one of the preceding claims, characterized in that the compressible medium (72) comprises a fluid, preferably a compressible gas, a compressible liquid or a combination thereof.
7. The device (12) of claim 3, characterized in that the receiving body (46, 146, 246) is fixable in the deep well (10) by means of at least one fixing arrangement (62, 64), preferably fixable relative to the inner casing (50) and/or outer casing (52), wherein in particular an axial movement of the receiving body (46, 146, 246) along the inner casing (50) and/or outer casing (52) is prevented,
   wherein, as an optional feature, the fixing arrangement (62, 64) is clamped relative to the inner casing (50) and/or the outer casing (52).
8. The device (12) of claim 7, characterized in that the fixing arrangement (62, 64) comprises at least one screw (70), preferably at least one stud screw which is preferably screwed against the inner casing (50) and/or the outer casing (52).
9. The device (12) of any one of claims 7 or 8, characterized in that the fixing arrangement (62, 64) comprises a fixing ring (63, 65) having a greater thickness extension in the radial direction than the receiving body (46, 146, 246) and preferably at least partially filling an annular space between the inner casing (50) and the outer casing (52),
   wherein, as an optional feature, the fixing ring (63, 65) has a variable wall thickness in the radial direction.
10. The device (12) of claim 9, characterized in that the fixing ring (63, 65) preferably has ribs (66) on its outer side with a respective clearance (68) therebetween, the ribs (66) being larger in the radial direction than any clearance (68).
11. The device (12) of any one of the preceding claims, characterized in that the receiving body (46, 146, 246) comprises a plurality of different closure members (58, 60),
    wherein, as an optional feature, the different closure members (58, 60) assume the open and the closed state in the case of a different pressure difference between the interior space and the environment.
12. The device (12) of any one of the preceding claims, characterized in that the receiving body (46, 146, 246) comprises a plurality of portions separated from each other by closure members (58, 60), the closure members (58, 60) preferably being configured to assume the open and the closed state in the case of a different pressure difference between the adjacent portions.
13. The device (12) of any one of the preceding claims, characterized in that the device (12) comprises a plurality of receiving bodies (46, 146, 246) preferably having different closure members (58, 60), wherein, as an optional feature, the plurality of receiving bodies (46, 146, 246) assume the open and the closed state in the case of a different pressure difference between the respective interior space and the environment.
14. A method for protecting deep wells (10) from pressure, in particular geothermal, oil, gas and/or cavern wells, by means of a device (12) of any one of claims 1 to 13, wherein at least one receiving body (46, 146, 246) is configured to receive a compressible medium (72) in an interior space and wherein at least one closure member (58, 60) is configured to assume an open and a closed state as a function of a predetermined pressure difference between the interior space of the receiving body (46, 146, 246) and an environment, the method comprising the steps of:

    pressurizing the receiving body (46, 146, 246) with a predetermined pressure;

    placing the receiving body (46, 146, 246) in the deep well (10);

    equalizing the pressure of a pressure difference between the interior space and the environment of the receiving body (46, 146, 246), wherein the closure member (58, 60) assumes an open state at least temporarily.

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