GEOTHERMAL WELL WITH COMMUNICATING VESSELS

Abstract

A geothermal well with communicating vessels includes: an internal piping transferring an inflow up to the level of the depth of the well; an inlet pump regulating the pressure of the fluid; an external piping, coaxial to the internal piping, with diameter allowing ascent of the fluid, from the distal end of the well upwards up to heat user device; a flange on the internal piping engaging a collar connected to the external piping through spacers; detection sensors transferring to a software the information on the oscillations of the pipings; an automatic safety valve to avoid overpressures; a driven regulation valve transferring to a software the information on the fluid pressure; and a dedicated software monitoring fluid circulation within the well, adapted to operate on the inlet pump, on the regulation valve and on a plurality of actuators, damping the oscillations and preventing microseisms.

Claims

1. Geothermal well with communicating vessels, adapted to transfer the endogenous heat of the deepest rock layers of the Earth's subsoil to a fluid specifically introduced inside a piping that is vertically extended below ground level; said piping also being adapted for extracting said fluid when it reaches the desired temperature and said fluid being adapted to be conveyed towards suitable heat exchangers and/or vapour generators, adapted to exploit said heat as energy source; said geothermal well comprising: A) an internal piping (20) adapted to transfer an inflow (41) of said fluid, from an inlet pump (40) up to a level determined by the depth of the well; B) at least one inlet pump (40), arranged at the inlet of said internal piping (20), adapted to regulate the fluid circulation pressure; C) an external piping (10), coaxial with said internal piping (20), with diameter suitable for allowing the ascent of the outflow (51) of said fluid, from the distal end of said well upward until it is conveyed into any one heat user device; the distal end of the well being the place where the heat exchange occurs between said fluid and the endogenous heat of the rock layers surrounding the walls of said external piping (10); D) at least one flange (24), arranged at the external surface of the internal piping (20); adapted to be engaged above at least one circular metal collar (15); said collar (15) being connected to the internal surface of said external piping (10) by means of a plurality of spacers (14) which, from the internal surface of said external piping (10), converge by following a linear path on said collar (15); said spacers (14) being constituted by common bars or plates made of any one metal or metal alloy; the engagement of said flange (24) with said collar (15) being adapted to provide structural support to the well, to ensure the centring between said external piping (10) and said internal piping (20) and adapted to prevent excessive oscillations between said internal piping (20) and said external piping (10) E) at least one automatic safety valve (70), arranged at the proximal end of said external piping (10) adapted to be activated, reversibly and automatically, so as to prevent overpressures of the circulating fluid; F) a plurality of detection sensors (60) adapted to transfer to a dedicated software, the information relative to the oscillations of said external piping (10) and of said internal piping (20) deriving from the pressure of the circulating fluid; G) at least one driven regulation valve (71), adapted to reversibly activated upon command of a common dedicated software, for the purpose of damping the excessive oscillations detected by said detection sensors (60); H) at least one common dedicated software adapted to ensure the safety of the plant by monitoring the fluid circulation inside the well and by receiving the input data coming from said detection sensors (60) and, possibly, by operating on said inlet pump (40) and on said driven regulation valve (71) in order to bring the parameters relative to the oscillations of said internal piping (20) and of said external piping (10) back within predetermined threshold values; said common dedicated software also being adapted to reversibly actuate a plurality of actuators, constituted by common motors and/or synchronous motors and/or flow regulation valves, adapted to dampen the oscillations and prevent the possibility of microseisms.

2. Geothermal well with communicating vessels, according to claim 1, wherein said external piping (10) is constituted by a plurality of modular elements (11), each of which constituted by a common cylindrical and hollow Mannesmann pipe, provided with a pair of threaded sections (12-12) arranged at the upper and lower ends of said modular element (11), said threaded sections (12-12) being adapted to allow the stable and reversible screwing and fixing of each modular element (11) with the subsequent modular element (11), until the desired depth is obtained for said external piping (10); said external piping (10) having a terminal element, adapted to represent the distal end of said piping and be installed at the maximum depth attained by the well after the last modular element (11), said terminal element being constituted by a cylinder provided with a threaded section (12) at the upper end and with a closure cap (13) at the lower distal end; said closure cap (13) being adapted to prevent the outflow of the fluid from said external piping (10) and its consequent dispersion in the ground.

3. Geothermal well with communicating vessels, according to claim 1, wherein said internal piping (20) is constituted by a plurality of modular elements (21), each of which constituted by a common cylindrical and hollow Mannesmann pipe, provided with a pair of threaded sections (22-22) arranged at the upper and lower end of said modular element (21), said threaded sections (22-22) being adapted to allow the stable but reversible screwing and fixing of each modular element (21) with the subsequent modular element (21), until the desired depth is obtained for said internal piping (20); said internal piping (20) having a terminal element, adapted to be installed after the deepest-arranged modular element (21), said terminal element being constituted by a cylinder provided with a threaded section (22) at the upper end and with a free end (23) at the lower end; said free end (23) being adapted to allow the outflow of said fluid from said internal piping (20) to said external piping (10).

4. Geothermal well with communicating vessels, according to claim 1, wherein the joining between two consecutive modular elements (11, 21), whether of said external piping (10) or of said internal piping (20), is sealed by means of a pair of Teflon layers, one arranged outside and one arranged inside said external piping (10) or said internal piping (20) at said joining.

5. Geothermal well with communicating vessels, according to claim 3, further comprising with a collar (15) provided with relative spacers (14) for each modular element (11) constituting the external piping (10); said geothermal well also comprising a flange (24) for each modular element (21) constituting the internal piping (20).

6. Geothermal well with communicating vessels, according to claim 1, wherein said spacers (14) are convergent in each collar (15), vertically aligned with the spacers (14) convergent in the subsequent collar (15).

7. Geothermal well with communicating vessels, according to claim 1, wherein said collar (15) is suitably sized for allowing the portion of internal piping (20) on which it abuts to make the necessary thermal expansions in linear direction and in cubic direction.

8. Geothermal well with communicating vessels, according to claim 1, comprising a closed circuit in which the heat of the fluid that constitutes said outlet flow (51), after having been exploited as energy source by a suitable user, is reintroduced into the circuit as cooled return fluid, constituting the new inflow (41).

9. Geothermal well with communicating vessels, according to claim 1, wherein said heat user is constituted by at least one common heat exchanger and/or by at least one common vapour generator.

10. Geothermal well with communicating vessels, according to claim 1, further comprising at least one detection sensor (60) arranged at said external piping (10) and at least one detection sensor (60) arranged at said internal piping (20); said detection sensors (60) being adapted to transmit to said common dedicated software at least the information relative to the oscillations of said external piping (10) and of said internal piping (20), said detection sensors (60) possibly also being adapted to transmit to said dedicated software the information relative to the chemical-physical characteristics of the circulating fluid and to the internal pressure of the well.

11. The geothermal well of claim 1, having exactly three of the spacers.

12. The geothermal well of claim 6, having exactly three of the spacers for each said collar.

13. Geothermal well with communicating vessels, according to claim 2, wherein said internal piping is constituted by a plurality of modular elements, each of which constituted by a common cylindrical and hollow Mannesmann pipe, provided with a pair of threaded sections arranged at the upper and lower end of said modular element, said threaded sections being adapted to allow the stable but reversible screwing and fixing of each modular element with the subsequent modular element, until the desired depth is obtained for said internal piping; said internal piping having a terminal element, adapted to be installed after the deepest-arranged modular element, said terminal element being constituted by a cylinder provided with a threaded section at the upper end and with a free end at the lower end; said free end being adapted to allow the outflow of said fluid from said internal piping to said external piping.

14. Geothermal well with communicating vessels, according to claim 2, wherein the joining between two consecutive modular elements, whether of said external piping or of said internal piping, is sealed by means of a pair of Teflon layers, one arranged outside and one arranged inside said external piping or said internal piping at said joining.

15. Geothermal well with communicating vessels, according to claim 3, wherein the joining between two consecutive modular elements, whether of said external piping or of said internal piping, is sealed by means of a pair of Teflon layers, one arranged outside and one arranged inside said external piping or said internal piping at said joining.

16. Geothermal well with communicating vessels, according to claim 2, wherein said spacers are convergent in each collar, vertically aligned with the spacers convergent in the subsequent collar.

17. Geothermal well with communicating vessels, according to claim 3, wherein said spacers are convergent in each collar, vertically aligned with the spacers convergent in the subsequent collar.

18. Geothermal well with communicating vessels, according to claim 4, wherein said spacers are convergent in each collar, vertically aligned with the spacers convergent in the subsequent collar.

19. Geothermal well with communicating vessels, according to claim 5, wherein said spacers are convergent in each collar, vertically aligned with the spacers convergent in the subsequent collar.

20. Geothermal well with communicating vessels, according to claim 2, wherein said collar is suitably sized for allowing the portion of internal piping on which it abuts to make the necessary thermal expansions in linear direction and in cubic direction.

Description

DESCRIPTION OF THE FIGURES

[0034] The invention will be described hereinafter in at least one preferred embodiment, provided by way of non-limiting example, with reference to the attached figures, wherein:

[0035] FIG. 1 shows an overall operating diagram of the geothermal well of the present invention which shows the external piping 10 and the internal piping 20 arranged in a concentric fashion. On the left of the drawing, the flow of the inflowing water 41 is illustrated which, passing through the inlet pump 40, is conveyed under high pressure in the internal pipings 20. As the water descends deeper, it gets hotter and hotter, thanks to the heat gradient present in the depth of the Earth. Upon reaching the bottom of the internal piping, the water flow, which is represented by increasingly darker arrows representing the temperature increase, ascends upwards into the space found between the external surface of the internal piping 20 and the internal surface of the external piping 10. The outflow 51, represented by the black arrow, is conveyed towards the heat exchanger and the vapour generators or any other instrument for utilising the plant. In addition, two detection sensors 60, the automatic safety valve 70 and the driven regulation valve 71, which monitor the safety and efficiency of the well through a dedicated software, are shown.

[0036] FIG. 2A shows a front view of a modular element 21 of the internal piping 20 and a modular element 11 of the external piping 10. In particular, the threaded sections 12 and 12 are shown at the two ends of the modular element 11 of the external piping 10, while other two threaded sections 22 and 22 are shown at the two ends of the modular element 21 of the internal piping 20. Such sections are designated for the stable engagement with the previous and subsequent modular element 11, 21, so as to form the pipings that descend deep into the ground.

[0037] FIG. 2B illustrates the same front view of the preceding figure but, in this case, regarding the terminal modular elements 11, 21 of the internal piping 20 and the external piping 10. The corresponding threaded section 22, 12 which enables connection with the overlying modular element 11, 21 is shown at the upper end of each modular element 11, 21. The lower end of the modular element 11 of the external piping 10 is provided with a closure cap 13. The lower end of the modular element 21 of the internal piping 20 is a free end 23 instead.

[0038] FIG. 2C shows a top view of the well, in which the external circumference representing the profile of the external piping 10, the internal circumference representing the profile of the internal piping 20 with the collar 15 on the external and three spokes present in the circular crown comprised between said internal piping 20 and said external piping 10, are shown. The three spokes represent the spacers 14, better visible and understandable with the help of the subsequent figure.

[0039] FIG. 3, as previously mentioned, shows a three-dimensional view of the deep structure of the well in which, besides the external piping 10 and the internal piping 20, there are the shown spacers 14 which, starting from the external piping 10, converge on the collar 15. It should be observed that the image is represented with a bottom to top view, i.e. from the bottom of the well towards the surface. As a matter of fact, at the top part of the collar 15, the engagement of the flange 24 is seen relative to the modular element 21 of the internal piping 20.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Now, the present invention will be illustrated purely by way of non-limiting example, with reference to the figures illustrating some embodiments regarding the present inventive concept.

[0041] With reference to FIG. 1, an operating diagram of the geothermal well of the present invention is shown. For a better understanding of the deeply innovative aspect of the present invention, it should be observed that wells used up to date require two drillings and a piping arranged deep horizontally connecting the water inflow piping to the outflow piping. Thanks to the present invention, the outflow piping contains the piping for the inflow of water, the fluid more generally. Thus, the external piping 10 and the internal piping 20 are coaxial and the internal piping 20 is sufficiently large to guarantee a slower ascent of the outflow 51 which occurs in the circular crown comprised between the external surface of the internal piping 20 and the internal surface of the external piping 10. This so as to enable a longer period in which the fluid is at contact with the external wall of the well and thus absorbs the thermal energy thereof.

[0042] Thus, when creating the well, only one drilling will be required instead of two.

[0043] For the understanding of the invention, we would like to emphasise on the great difference that a vertical circuit has with respect to a well of the type used up to date, i.e. having a fluid path in the horizontal direction between the well, in inflow and outflow. Given that the thermal gradient increases proportionally to the increase of depth, a vertically extending system enables regulating the flow rate to the thermal power demand.

[0044] Still with reference to FIG. 1, the arrows show the fluid path. The first white arrow on the left shows the inflow 41 whichthrough the inlet pump 40is conveyed into the internal piping 20 at the desired pressure. Descending deeper, the fluid absorbs the endogenous heat transmitted by the deepest rock layers. We would like to point out that the depth of the well depends on the type of rocks encountered through core sampling carried out during the preliminary study of the site. The depth thereof will be established at the planning stage as a function of the temperature detected deep down.

[0045] Increasingly hotter, the fluid reaches the distal end of the well and, given that the internal piping 20 is open, said fluid is made to flow into the external piping 10. The ascent, represented by the black arrows which constitute the outflow 51, begins from here. The latter is conveyed towards at least one special heat user device which may be both a common heat exchanger and a common vapour generator. At this point, the fluid has been cooled and it is reintroduced into circulation as a cooled return fluid, constituting a new inflow 41.

[0046] The reintroduction of the circulating fluid, eliminates the possibility of occurrence of the subsidence phenomenon, i.e. the sinking of the soil due to the extraction of the aquifer.

[0047] With the aim of also eliminating the microseisms that currently occur in common geothermal wells, the plant of the present invention is provided with numerous precautions for damping the oscillations generated in the internal piping 20. More precisely, the configuration of concentric flows of the well, already guarantees a given level of damping of the oscillations in that, flowing in the opposite direction, the vibrations generated by the inflow 41 at least partly nullify the vibrations generated by the ascending flow. Furthermore, a circular flange 24 is arranged outside said internal piping 20 so as to support such damping of the oscillations, ensure the maintenance of coaxiality between the two pipings and simultaneously enable the inevitable thermal expansions. Said flange 24 is adapted to be engagedat the upper partwith a circular collar 15belonging to the external piping 10 and connectedat the internal surface thereofthrough a plurality (preferably three) of spacers 14, constituted by common bars or plates made of any metal or metal alloy, adapted to provide structural support, between the two pipings.

[0048] FIG. 3 exhaustively shows the mutual engagement between the components described above. It should be observed that the fluid is introduced into the internal piping 20 at a very high pressure, amounting to about 200 bars, thus the oscillations may be rather considerable. More in detail, said collar 15 will be suitably dimensioned to enable possible thermal expansions, both in linear and cubic direction, due to the high operating temperatures. Even more in detail, said collars 15 with the relative spacers 14, are arranged at regular intervals, in particular, in case of pipings constituted by modular elements 1, 21, there will be a collar 15 with spacers 14 for each modular element 11 of the external piping 10 and a flange 24 for each modular element 21 of the internal piping 20.

[0049] The stiffening mechanical systems, are supported by an electronic control system through a dedicated software adapted to prevent the aforementioned microseisms.

[0050] In particular, the well is provided with at least one detection sensor 60 at the external piping 10 and a detection sensor at the internal piping 20. The latter are adapted to transfer to said dedicated software, the information regarding the oscillations of the pipings 10, 20 deriving from the pressure of the circulating fluid. Possibly and preferably, said detection sensors 60 may also be adapted to communicate to said software the information regarding the chemical-physical composition of the circulating fluid and regarding the circulating pressure thereof.

[0051] Upon collecting this information, said dedicated software is capable of damping oscillations should the return flow vibrations not be sufficient to bring them back within the pre-set threshold. In particular, said software operates through the following means: a driven regulation valve 71, the inlet pump 40 and a plurality of actuators, constituted by common motors and/or synchronous motors and/or flow regulation valves, suitable to dampen the oscillations and prevent potential microseisms.

[0052] Said well is also provided with an automatic safety valve 70, adapted to automatically operate in case of detection of an overpressure of the circulating fluid.

[0053] Also the construction characteristics of the well of the present invention reveal innovative advantages. Both the external piping 10 and the internal piping 20, are constituted by a plurality of modular elements 11, 21 mutually coupled one after the other, up to reaching the project depth. Said modular elements 11, 21, are constituted by common cylindrical and hollow Mannesmann pipes (i.e. without welding), provided with a pair of threaded sections 12-12, 22-22 arranged at the upper and lower end of said modular element 11, 21. Said threaded sections 12-12, 22-22 are adapted to enable the stable but reversible screwing and fixing of each modular element 11, 21 with the subsequent one, up to obtaining the desired depth. Each joining between one modular element 11, 21 and the other is sealed by means of a Teflon layer arranged inside and outside the joining.

[0054] The only elements representing an exception with respect to the above, are the terminal elements of both pipings 10, 20, as exhaustively represented in FIG. 2B. In particular, the terminal element of the external piping 10, which represents the distal end thereof, is represented by a cylindrical and hollow body, provided with a threaded section 12, like the one described previously, which enable the screwing thereof with respect to the overlying modular element 11. The opposite end is instead provided with a closure cap 13 adapted to prevent the outflow of the fluid from said external piping 10 and the ensuing dispersion thereof into the ground.

[0055] The terminal element of the internal piping 20, is instead constituted by a cylindrical and hollow element provided with a threaded section 22 at the upper end, for screwing thereof to the overlying modular element 21, and with a free end 23 at the lower end. This to enable outflow of the fluid from the internal piping 20 to the external piping 10.

[0056] Lastly, it is clear that the invention described up to now may be subjected to modifications, additions or variants obvious to a man skilled in the art, without departing from the scope of protection outlined by the attached claims.