ITRM20120211A1 - EXCAVATION SYSTEM FOR THE EXCAVATION OF A WELL AND / OR FOR THE REALIZATION IN THE UNDERLYING OF ONE OR MORE SLOTS TO BE USED AS RADIANT SURFACES FOR THE EXPLOITATION OF GEOTHERMAL ENERGY. - Google Patents

Description

EXCAVATION SYSTEM FOR THE EXCAVATION OF A WELL AND / OR FOR THE CREATION OF ONE OR MORE CRACKS IN THE UNDERGROUND TO BE USED AS RADIANT SURFACES FOR THE EXPLOITATION OF GEOTHERMAL ENERGY

The present invention relates to the renewable energy sector, such as that of geothermal energy, and refers to an excavation system for digging a well and / or for the creation of one or more cracks in the subsoil to be used as radiant surfaces for the exploitation of geothermal energy.

In particular, the invention relates to an excavation system which makes it possible to make a crack in the subsoil below the bottom of a well. This well can be a pre-existing well already dug into the ground or it can be dug into the ground by means of the excavation system itself. The depth of the well is chosen according to the temperature and / or mechanical resistance of the rock layer in the subsoil.

To date, the exploitation of geothermal energy can be divided into two categories:

1. the exploitation of the average temperature (from 14 ° to about 18 °) of layers located a few meters below the surface, which temperature remains almost constant throughout the year; And

2. the exploitation of the high temperature (higher than 100 °) of layers located in depth.

In the first case, relating to the exploitation of average temperatures, the layers below the earth's surface are used as a heat exchanger for the heat pumps present in air conditioning systems.

Known type of air conditioning systems heat or cool an environment, for example a house, at the request of the user according to the current season.

Said air conditioning systems can take as reference temperature the temperature of the external air or that of the ground on which said house is located.

In the latter case, the air conditioning system must work on a lower temperature difference than that between the house and the outside air. This determines a lower energy consumption by said conditioning system.

To obtain a sufficient amount of energy for an average house (about 60sqm), an investment is required which can be modest, if the installation of a heat exchanger in the ground is done during the construction phase of the building, for example on the bottom of the building. excavation done to perform the foundations or significant, if the house has already been built and a heat exchanger of adequate size must be installed.

More and more companies are offering solutions on the market based on heat pump technology.

In the second case, relating to the exploitation of high temperatures, it is possible to exploit the heat to produce steam and drive turbines that can produce electricity.

Currently, for the exploitation of geothermal energy, sites that have permeable layers in the subsoil are used almost exclusively.

Since the costs of digging a well can be significant, mainly due to the fact that it takes a few months to reach certain depths, it is necessary to carry out preventive research. Such preventive searches can be carried out on the surface with special machinery, to identify at certain depths the presence of sufficiently large layers consisting not of compact rock, but of pebbles or in any case rock formations that are easily permeable to water.

This is because a well dug only in compact rock has the disadvantage that the thermal conductivity of said rock is not very high (for example, granite has a conductivity equal to 3.5 Kcal / m h ° C) and the surface of the walls of the well, although the well is deep (for example 5 km) it is in total of about 2000sqm. From this, it is clear, by means of simple calculations of a known type, that the energy that can be obtained from such a well is sufficient only for about fifteen houses.

On the contrary, if one or more permeable layers are present at the bottom of the well, the radiant surface can be considered in correspondence with said layers which is considerably higher.

If the permeable layer is sufficiently extended, a plurality of wells can be made so that water can be introduced into one or more of said wells and that steam can be extracted from wells other than those into which the water.

In fact, in correspondence with wells on the bottom of which there is a permeable layer, power stations have been built for the exploitation of thermal energy and / or steam.

However, the geographical sites where to dig for a permeable layer are very limited.

Currently, much faster and cheaper excavation techniques are being developed, even in compact rock, which could make it economical to exploit sites with different rock formations.

To date, a technique for increasing the radiant surface consists in making a well, digging into the ground to a desired depth, filling said well with water, and exerting a pressure on said water by means of a known type so that on the bottom of the well one or more fractures are created.

However, fractures with this technique may not be communicating with each other. In this case, it is necessary to dig further wells, in an intermediate position to those created or planned, and create further fractures that are communicating with the previous fractures.

Another technique is to use explosives that are blasted at the bottom of a well to increase the radiant surface.

This entails the disadvantage of necessarily drilling further wells with the consequent high costs.

The object of the present invention is to overcome said disadvantages by providing an excavation system for the excavation of a well and / or for the creation of one or more cracks in the subsoil to be used as radiant surfaces for the exploitation of geothermal energy.

Therefore, the specific object of the present invention is an excavation system for the excavation of a well and / or for the creation of one or more cracks in the subsoil to be used as radiant surfaces for the exploitation of geothermal energy, where said excavation system includes:

- at least one drilling arm for drilling the ground along the axial direction of said drilling arm, said drilling arm having a first end and a second end, opposite to said first end,

- at least one excavation probe having a first end coupled to said first end of said at least one drilling arm, and a second end, opposite to said first end,

- actuation means for operating said excavation probe;

- mobile cutting means for cutting rock layers in such a way as to create a crack in the subsoil e

- actuation means for actuating said movable cutting means.

In a first configuration, said excavation system can comprise a first drilling arm and a second drilling arm, a first excavation probe and a second excavation probe, each of which is coupled to the first end of a respective drilling arm. In particular, said actuation means can be connected to the second end of each drilling arm and can also be direction means for directing each excavation probe. The mobile cutting means can comprise a diamond cable slidingly coupled with said first excavation probe and with said second excavation, and said diamond cable can extend along said drilling arms and between said drilling arms. Furthermore, said excavation system can comprise a pulley arranged on the surface, around which said diamond cable runs, and said pulley can be movable with respect to the entrance to the well between an initial position, in which it is external to the well, at a first distance from the predetermined well inlet, to a final position, in which it is either external to the well, at a second distance from the well inlet, where said second distance is less than said first predetermined distance, or inside the well itself. In this first embodiment, the drilling arms and the cutting means cooperate with each other to crush rock layers in such a way as to create said crack in the subsoil.

According to the invention, each excavation probe can be equipped with a respective pulley for said diamond cable, and said actuation means for said cutting means can comprise at least one of said pulleys, where said at least one pulley is a driving pulley. It is preferable that said excavation system preferably comprises two return pulleys, each of which is arranged on a respective drilling arm.

Still according to the invention, respective drilling means can be coupled on the second end of each excavation probe, and said drilling means can be provided with one or more respective holes or openings to allow a quantity of water to escape from them and drag the crushed rock debris to the surface. Each drilling arm can have the second end connected to a water pump, where said water pump pumps water into said drilling arms, and each excavation probe can comprise a hydraulic motor to drive said drilling means.

It is preferable that said perforation means are provided with one or more reliefs, and even more preferable that at least one relief comprises a piezoelectric or sonodoto transducer.

Advantageously, said drilling means can be removably coupled to the second end of the respective excavation probe.

Still advantageously, each excavation probe can comprise a respective first part and a respective second part, as well as a respective joint which connects said two parts.

Furthermore, each excavation probe can comprise a respective guide element for maintaining the excavation probe itself in a correct position when the excavation system is in use, and preferably respective detection means for determining the position of the excavation probe itself.

In particular, said diamond cable can comprise one or more inserts arranged on said diamond cable in such a way as to be spaced from each other, and at least one insert can preferably comprise a piezoelectric or sonodoto transducer.

In a further configuration, said movable cutting means for cutting rocky layers can comprise a first diamond cable and a second diamond cable, and said actuation means for operating said movable cutting means can comprise an articulated quadrilateral which comprises:

- a first pulley system for said diamond cables, each of which can be rolled up / unwound on a first block, said first pulley system comprising a first pulley and a second pulley, arranged along a first axis, each of which rotates on a second axis orthogonal to said first axis,

- a guide element arranged centrally between said first pulley and said second pulley, - a first pair of arms for said first pulley and a second pair of arms for said second pulley, where the arms of each pair have a first end pivoted on a respective pulley and the second end pivoted slidingly on said guide element in such a way that said two pulleys pass from an initial position, in which the arms of each pair are aligned along a first direction and each arm of the first pair is substantially in contact with a respective arm of the second pair, to a final position, in which each arm of the first pair is aligned with a respective arm of the second pair along a second direction, orthogonal to said first direction, and the arms of each pair are substantially in contact between They. It is also preferable that said excavation system comprises a respective return pulley for each diamond cable.

According to the invention, in this further configuration, said excavation probe can comprise:

- a second pulley system and a third pulley system to allow the sliding of a third diamond cable and a fourth diamond cable respectively,

where said second pulley system comprises a first pulley and a second pulley, each of which rotates respectively on a first rotation axis and on a second rotation axis, said two rotation axes being parallel, and said third pulley system comprises a first pulley, a second pulley and a third pulley; the first pulley and the third pulley of said third pulley system rotating on said first axis of rotation in the opposite direction to the direction of rotation of the first pulley of the second pulley system; said first pulley and said third pulley of the third pulley system being positioned laterally to said first pulley of the second pulley system; the second pulley of the third pulley system rotating on a third axis of rotation, parallel to said first axis of rotation and to said second axis of rotation;

- a first pair of blocks on which said third diamond cable at least partially can be rolled up / unwound, comprising a first block and a second block;

- a second pair of blocks on which said fourth diamond cable can be rolled up / unwound at least partially, comprising a first block and a second block,

where the first block of each pair is movable between an initial position, in which it is inside the well, at a first distance from the well entrance, to a final position, in which it is or inside the well, at a second distance from the well entrance, where said second distance is less than said first distance, or on the surface, at a third distance from the well entrance, and said second block of each pair is on the surface, at a predetermined distance from entrance to the well.

Furthermore, said actuation means can comprise a hydraulic motor to actuate said third diamond cable and said fourth diamond cable, and said first pulley of the second pulley system is preferably provided with a central circumferential projection which divides it into a first part and a second part. starts, in such a way that the third diamond cable winds in an orderly manner on said first pulley.

In particular, the excavation probe can comprise a first toothed wheel, a second toothed wheel on which the second pulley of the third pulley system is coupled, said second toothed wheel being meshed with said first toothed wheel, and a third toothed wheel on which the second pulley of the second pulley system is coupled, said third toothed wheel being meshed with said second toothed wheel, and said hydraulic motor can transmit motion to said first toothed wheel in such a way that the second toothed wheel rotates in the opposite direction to that of said first toothed wheel, and that the third toothed wheel rotates in the opposite direction to that of said second toothed wheel.

According to the invention, both in the first configuration and in the further configuration mentioned above, said at least one excavation probe can further comprise at least one controlled hydrodynamic cavitation device for generating cavitation bubbles, in particular pico-bubbles, nano-bubbles and micro-bubbles. bubbles.

With reference to the first configuration, each excavation probe can comprise a respective first controlled hydrodynamic cavitation device and a second respective controlled hydrodynamic cavitation device, where each first controlled hydrodynamic cavitation device is positioned between the first end of the respective excavation probe and a point of said excavation probe at which a respective pulley for the diamond cable is coupled, and each second controlled hydrodynamic cavitation device is positioned between said point and the second end of the respective excavation probe. Furthermore, a pipeline equipped with nozzles can connect the first controlled hydrodynamic cavitation device of the first excavation probe to the first controlled hydrodynamic cavitation device of the second excavation probe such that, when said first controlled hydrodynamic cavitation devices are in use, these nozzles inject the cavitation bubbles on the diamond cable and on the rocky layers. In particular, said pipe can comprise at least two rigid pipes connected to each other by means of a first connecting element and be connected to each first device for controlled hydrodynamic cavitation of the excavation probes by means of a respective second connecting element. Each second connecting element has one end connected to a respective outlet of a first controlled hydrodynamic cavitation device and the other end connected to said pipe. Said first connecting element and said second connecting elements allow the pipe to pass from a first position, in which said two rigid pipes are substantially vertical and in contact with each other, to a second position, in which said two rigid pipes are substantially aligned horizontally .

Advantageously, the excavation system can comprise one or more blocks arranged on the surface, and said pipe can be connected to said one or more blocks by means of one or more cables, each of which can be rolled up / unwound at least partially on said blocks.

According to the invention, each first controlled hydrodynamic cavitation device and each second controlled hydrodynamic cavitation device can comprise a hydrodynamic motor, rotating around its axis of rotation, a rotor, a stator inside which said rotor is positioned.

In particular, said second controlled hydrodynamic cavitation device can further comprise a rotating head, integral with the rotor, equipped with a plurality of injectors to inject cavitation bubbles outside through the holes or openings of the perforation means.

Furthermore, according to the invention, the hydrodynamic motor can be inside a casing and one or more magnetic shock absorber bearings can be positioned on said casing to dampen the vibrations to which said hydrodynamic motor is subject when the excavation system is in use.

The present invention will now be described, for illustrative but not limitative purposes, according to its embodiments, with particular reference to the attached figures, in which:

Figure 1 schematically shows the excavation system for the realization of radiant surfaces in the subsoil, object of the invention inserted in a well already excavated in the ground;

figure 2 shows a detail relating to an excavation probe of a drilling arm of the excavation system of fig. 1;

figure 3 schematically shows a substantially triangular-shaped crack dug in the subsoil by means of the excavation system of fig. 1;

figure 4 schematically shows the slot of fig. 3 in which pipes have been inserted for the transport and injection of water in this slot in order to generate steam, and a further duct for collecting and transporting this steam to the surface, inserted at least partially in the well;

Figures 5-6 schematically show the probes for excavating the drilling arms respectively in a first position, where they diverge, and in a second position, where they converge;

figure 7 schematically shows a substantially rhombic-shaped crack dug in the subsoil by means of the excavation system of fig. 1;

figure 8 schematically shows the slot of fig. 7 in which pipes have been inserted to transport and inject water into this slot for the generation of steam, and a further duct to collect such steam, inserted at least partially in the well;

Figure 9 partially shows a second embodiment of the excavation system, where each excavation probe is equipped with a first and a second controlled hydrodynamic cavitation device for generating cavitation bubbles;

figure 10 is a perspective view of a diamond cable portion of the excavation system of fig. 9, which diamond cable is equipped with inserts; figure 11 shows the cavitation bubbles between the inserts of the diamond cable and the rock layer;

figure 12 shows the evolution of a cavitation bubble from its generation to its implosion;

Figures 13-14 respectively show small rock debris attracted by cavitation bubbles, and larger rock debris attracting cavitation bubbles;

figure 15 shows a variant of the diamond cable of fig. 10, where the inserts of the diamond cable are equipped with a piezoelectric or sonodoto transducer;

Figure 16 schematically shows the first controlled hydrodynamic cavitation device present in the excavation probe;

Figure 17 schematically shows the second controlled hydrodynamic cavitation device present in the excavation probe;

Figure 18 is a bottom view of the excavation means provided on the excavation probe;

figure 19 shows a third embodiment of the excavation system comprising a drilling arm;

figure 20-22 show a pulley system for two diamond cables of the excavation system of fig. 19, through which a crack is created in the subsoil, in an initial, intermediate, and final position respectively;

figure 23 schematically shows how the two diamond cables slide with respect to the pulley system of fig. 22;

figure 24 shows a detail of the third embodiment of fig. 19, relating to the excavation probe comprising two systems of pulleys for a respective diamond cable through which the ground is drilled;

figure 25 shows the same detail of fig. 24 where the pulleys rotating on the same rotation axis are spaced apart for a better understanding of the operation of the two pulley systems;

figure 26 further shows the detail of the excavation probe comprising the two pulley systems;

figure 27 schematically shows how the hydraulic motor transmits motion to the third diamond cable and to the fourth diamond cable of the excavation system of fig.

19;

Figure 28 schematically shows, in correspondence with an excavation plant, a substantially triangular-shaped crack dug in the subsoil having;

Figures 29-30 schematically show in correspondence with an excavation plant, respectively, a substantially rhombic-shaped slot dug in the subsoil, and a plurality of substantially rhombic-shaped slits dug in the subsoil.

With particular reference to figure 1, an excavation system is provided for the realization of a radiant surface in the subsoil, below the bottom of a well.

In the first embodiment that is described, the excavation system is inserted in a pre-existing pit. However, said pit can be excavated by the excavation system itself.

This excavation system includes:

- a first drilling arm 1 and a second drilling arm 1 for drilling the ground along the axial direction of each arm, each of which has a first end equipped with a respective excavation probe 10, 10 ', and a second end, opposite said first end,

- cutting means 2 for cutting the rocky layer between said two drilling arms.

In particular, said cutting means 2 comprise a diamond cable 20 which extends along said drilling arms 1, 1 and between said drilling arms, from one excavation probe to the other, so that said drilling arms 1, 1 ' are connected to each other by means of said diamond cable.

The excavation system also comprises means for actuating and directing the excavation probes 25 to actuate the excavation probes 10, 10 'and direct them underground, connected to the second ends of said drilling arms 1,1', and actuation means 12 to actuate said cutting means 2. In the example being described, said means of actuation and direction 25 of the excavation probes 10,10 'are means of the electric type, and comprise an electric motor which is connected to each probe of excavation 10, 10 'by means of a respective electric cable (not shown). However, said actuation and direction means 25 can be of the hydraulic type, and comprise a hydraulic motor, without thereby departing from the scope of the invention.

The drilling arms 1, 1 'and the cutting means 2 cooperate to drill the ground in such a way as to dig a crack F in the subsoil.

In particular, each excavation probe 10, 10 'has a first end connected to a drilling arm and a second end on which respective drilling means 11,11' are provided. Said drilling means 11, 11 'can be coupled / uncoupled to the excavation probes. This allows to easily remove said drilling means for their replacement. Furthermore, the fact that said drilling means 11,11 'can be removed from the respective excavation probes 10,10' allows said excavation probes not to necessarily foresee the presence of said drilling means, for example when the cavities have already been excavated by a drill arm.

Each excavation probe 10,10 'comprises a respective first part ΙΟA, ΙΟ'A and a respective second part 10B, 10B', as well as a respective joint 15,15 'which connects said two parts.

At the end of each first part 10A of the excavation probes 10,10 'the drilling means 11,11' are provided. The latter are equipped with one or more respective holes or openings H A, 11Ά to allow a quantity of water to escape from them and drag the rocky debris of the crushed rock layers towards the surface as the drilling arms 1, 1 '( fig. 2). The water is pumped inside the drilling arms 1,1 'by means of a pump 30 external to the excavation system, and connected to them.

As can be seen from Figure 2, each excavation probe 10, 10 'comprises a respective guiding element 16,16' for keeping the excavation probe in a correct position when the slot F is excavated. Said guiding element is a ' wing protruding from the respective excavation probe in such a way that, when the slot F is excavated, the free end of said wing is inside said slot.

Each excavation probe 10, 10 'further comprises respective detection means 14, 14' for determining the position of the excavation probe itself. Said detection means can be sonar or radio wave type sensors.

Each excavation probe 10, 10 'comprises a hydraulic motor (not shown) for driving said drilling means 11, 11', which can be a turbine or lobe type. Said hydraulic motor is driven by the same water which is pumped inside the drilling arms 1,1 'by means of the pump 30.

The movement of one drill arm is independent of the movement of the other arm. In the example described, the drilling arms are lowered into the well side by side, and at the bottom of the well they are made to diverge in such a way that an angle is formed between them to create a slot. However, the drill arms can also be inserted into the well already diverging, when the dimensions of the well allow it.

Each excavation probe 10, 10 'comprises an electronic control unit which in connection with a data processing unit (not shown) on the surface allows an operator to monitor and control the excavation parameters, such as position, temperature, pressure, humidity. , digging speed, acceleration. In this way, the operator can monitor the movements of the excavation probes 10, 10 'with respect to a longitudinal axis passing through the center of the well, so as to constantly check their position and that of the diamond cable 20. A constant voltage of the diamond wire maximizes the cutting effect of the rock material.

Alternatively, it is possible to control the movements of the excavation probes 10,10 'by analyzing the excavation speed of the excavation probes and the sliding speed of the diamond cable 20 by means of geometric calculations.

The means for driving the diamond cable 20 comprise two driving pulleys 120, 120 ', each provided on the second part 10B, 10'B of the respective excavation probe 10, 10'. However, to operate the cutting means 2 it is sufficient for one of said pulleys to be a driving pulley, without thereby departing from the scope of the invention.

Said driving pulleys 120, 120 'are driven by the same hydraulic motor which drives the drilling means 11 of the same excavation probe 10 and is equipped with means for controlling the tension of the diamond cable 20 (not shown in the figure) to control the tension of the diamond cable 20 at any time, which progressively lengthen or reduce the portion of diamond cable 20 between the two pulleys. For example, said tension control means can comprise a lever having one end integral with an excavation probe and one end in contact with the diamond cable 20.

The excavation system comprises further pulleys: a further pulley 32 on the surface to allow the diamond cable 20 to remain taut, and two further pulleys 13,13 ', each arranged underground at the bottom of the well. Said further pulley 32 is movable with respect to the well inlet between an initial position, in which it is external to the well, at a first predetermined distance from the well inlet, to a final position, in which it is either external to the well, to a second distance from the well inlet, which second distance is less than said first predetermined distance, or inside the well itself. In other words, said further pulley approaches or moves away from the entrance to the well, depending on the depth reached by the excavation probes 10, 10 ', that is, depending on whether the diamond cable 20 is respectively made to descend into the subsoil or to rise. In its initial position, said further pulley 32 is held by support means (not shown), such as for example a winch.

In Figure 1, the drilling arms 1,1 'have been spread apart in such a way as to form a certain angle between them so that a slot of substantially triangular section is formed in the subsoil, where the inclined sides of said triangular section correspond to the hollowed cavities by the drilling arms 1, 1 'and the base of said section corresponds to the cavity hollowed out by the cutting means 2.

Figure 3 schematically shows the slot with a substantially triangular section excavated in the subsoil by means of the excavation system.

In particular, once the crack in the subsoil has been created, the excavation system is removed and pipes 23 are inserted, having a length equal to the length of the cavity dug by the drilling arms 1,1 'into which they are inserted, to transport and inject water. in this crack so that, from the contact of the water with the rocky layer of the crack, steam is generated which is collected on the surface. To this end, an insulated steam collection duct 18 is inserted at least partially into the well (Fig. 4) to allow the steam to be channeled towards the surface. In particular, the pipes 23 for the transport and injection of water have a first end or upper end connected to a water pump and a second end or lower end to which a plurality of pipes 233 are fixed by means of a corresponding connecting element. fitting 234, each of which is equipped with nozzles 233A to inject the water into the slot F. In the example described, the pipes 23 are also equipped with nozzles 23A to inject water into the slot F.

With reference to Figures 5 and 6, the excavation probes 10,10 'of each drilling arm 1,1' are shown, which respectively begin to converge, and which converge towards a common point.

When the two drilling arms 1,1 'converge towards a common point, the diamond cable 20 has passed from a first triangular configuration, where the lateral portions of the cable extend along the drilling arms, to a second triangular configuration, where the lateral portions extend in the area between the two drilling arms.

When the drilling arms are made to converge, the slot F passes from a substantially triangular shape to a substantially rhombic shape (fig. 7).

Once this crack has been created in the subsoil, the excavation system is removed and pipes 23 are inserted to transport water and inject it into this crack by means of nozzles 23A (fig. 8), so that the steam, generated by the contact of the injected water with the rocky layer of the crack, is collected on the surface, by means of a collection duct.

In a second embodiment of the excavation system shown in Figure 9, each excavation probe 10,10 'comprises inside a respective first controlled hydrodynamic cavitation device 29A, 29A' and a respective second controlled hydrodynamic cavitation device 29B, 29B 'to generate cavitation bubbles, in particular micro-, nano- and pico-bubbles. By this embodiment, the rock material is crushed by the combined action of the diamond cable 20 and the cavitation bubbles.

With reference to the excavation probes 10,10 ', the first hydrodynamic cavitation device 29A, 29A' is positioned between the first end of the respective excavation probe 10,10 'and a point of the same excavation probe at which it is fixed the driving pulley 120, 120 'for the diamond cable 20, and the second hydrodynamic cavitation device 29B, 29B' is positioned between said point and the second end of the respective excavation probe.

The first hydrodynamic cavitation device 29A of the excavation probe 10 of the first drilling arm 1 is connected to the first hydrodynamic cavitation device 29A 'of the excavation probe 10' of the second drilling arm 1 ', by means of a pipe 28 equipped with nozzles 28A to inject said cavitation bubbles into the slot. This pipe 28 comprises at least two rigid pipes connected to each other by means of a first connecting element 27, and is connected to each first controlled hydrodynamic cavitation device 29A, 29A 'of the excavation probes 10, 10' by means of a respective second connecting element 277,277 having one end connected to the outlet of each first controlled hydrodynamic cavitation device 29A, 29A 'and the other end connected to said pipe 28. Said first connecting element 27 and said second connecting elements 277,277' allow said pipe 28 to pass from a first position, in which said two rigid pipes are substantially vertical and in contact with each other, to a second position, in which said two rigid pipes are substantially aligned horizontally.

Furthermore, said pipe 28 is connected to one or more blocks 40 on the surface by means of one or more cables 41, which can be rolled up / unwound on said blocks, so as to avoid any contact between said pipe 28 and said diamond cable 20.

The cutting means 2 comprise, in addition to the diamond cable 20, a plurality of inserts 20A arranged on the diamond cable itself spaced apart (fig.

10). Said inserts 20A exert a pressure on the cavitation bubbles until they cause said bubbles to implode (fig. 11).

Figure 12 schematically shows the evolution of a cavitation bubble from its formation to its implosion. Implosion causes localized energy to be released in the form of shock waves. The collapse of these cavitation bubbles produces intense local heating, high pressures, as well as cavitating supersonic jets. The latter exploit the possibility of creating cavitation phenomena by generating vapor bubbles in the liquid which imploding generate very high pressure pulses. The rocky debris which is formed as a result of the action of the drilling arms 1,1 'and of the diamond cable 20 can have different dimensions. Regardless of their size, such rock debris is dragged to the surface by the cavitation bubbles that arrange themselves around the rock debris and drag it upwards.

In particular, in figure 13 small rocky debris are shown, of the order of magnitude of the nanometer and picometer, which are attracted by the cavitation bubbles and dragged towards the surface, and in figure 14 the rocky debris of larger dimensions are shown. large, in the order of magnitude of the micrometer and nanometer, which attract the cavitation bubbles and are dragged towards the surface.

In a variant shown in Figure 15, each insert 20A of the diamond cable 20 comprises a piezoelectric or sonodoto transducer 43 for generating ultrasonic vibrations which are transmitted to said diamond cable 20 through the excavation probe. This allows the diamond cable 20 to function both as a mechanical means for eroding and dragging the rocky material and as a lithotripter means for the rocky material, i.e. as a source of high intensity mechanical waves.

Each controlled hydrodynamic cavitation device comprises a hydrodynamic motor 35 driven by the water pumped by the pump 30 inside the respective excavation probe, rotating around its axis of rotation 35A, a rotor 36, a stator 37 inside which said rotor.

In particular, each first controlled hydrodynamic cavitation device 29A, 29A 'generates cavitation bubbles which are sent inside the pipe 28 and injected by means of the nozzles 28A on the portion of diamond cable 20 between the two drilling arms 1, 1 '(fig.

16).

Each second controlled hydrodynamic cavitation device 29B, 29B 'further comprises a rotating head 38, integral with the rotor 36, equipped with a plurality of injectors 39 to inject cavitation bubbles outside through the openings HA provided on the perforation means 11 (fig . 17).

In particular, the hydrodynamic motor 35 is inside a casing 34 and magnetic shock-absorbing bearings 38 are provided on said casing to dampen the vibrations to which the motor 35 is subjected due to the crushing of the rocky material during excavation.

In the second embodiment that is described, the perforation means 11, 11 'have a plurality of reliefs 11B shaped in such a way as to form four petals (Fig. 18).

Said reliefs 11B are made with materials suitable for abrasive and hard conditions, such as for example tungsten carbide and / or with a sintered matrix covered with polycrystalline synthetic diamond or diamond, and this allows for faster advancement and longer life even in crushing of the most difficult and abrasive layers.

In particular, each relief 11B comprises a plurality of piezoelectric transducers or sonodrots 433, so that the rock layers are subjected to the action of the excavation means equipped with reliefs incorporating said piezoelectric translators and to the action of the cutting means, optimized by the generation of the cavitation bubbles.

The second embodiment has the advantage that the excavation system object of the invention can be used to dig oil wells, or to transform existing oil wells with residual crude or unconventional crude oil, by gasifying it through micro-bubbles, nano-bubbles, and pico-bubbles generated by the hydrodynamic cavitation devices present in the excavation probes.

Advantageously, the nozzles provided for the injection of these cavitation bubbles are able to increase the flow speed so that a greater production of cavitation bubbles is obtained and the excavation phase is speeded up.

In the event that the excavation system is used for the excavation of oil wells, even a possible phase of conversion of hydrocarbons until exhaustion can be speeded up.

With reference to Figures 19-26, in the third embodiment that is described, an excavation system is provided which comprises a drilling arm 100 for drilling the ground.

With particular reference to figures 19-22, for the creation of the crack in the subsoil, the excavation system includes an articulated quadrilateral to allow the sliding of a first diamond cable CI and a second diamond cable C2, each of which can be rolled up / unwound. on a first block 139.

Said articulated quadrilateral comprises a first pulley system, which comprises a first pulley 130 and a second pulley 131, arranged along a first axis X, each of which rotates on a second axis orthogonal to said first axis.

Said articulated quadrilateral further includes:

a guide element 136 arranged centrally between said first pulley 130 and said second pulley 131, a first pair of arms 132,133 for said first pulley 130 and a second pair of arms 134,135 for said second pulley 131, where the arms of each pair have a first end pivoted on a respective pulley and the second end pivoted slidingly on said guide element 136 in such a way that said two pulleys 130, 131 pass from an initial position, in which the arms of each pair are aligned along a first direction and each arm of the first pair is substantially in contact with a respective arm of the second pair (fig. 20), at a final position, in which each arm of the first pair is aligned with a respective arm of the second pair along a second direction, orthogonal to said first direction, and the arms of each pair are substantially in contact with each other (fig. 22).

In an intermediate position between the initial position and the final position, the arms of each pair are inclined with respect to said guide element 136, forming an angle with it (fig. 21)

For each diamond cable Cl, C2, a respective transmission pulley 137, 138 is provided, visible in figure 23 which shows how each diamond cable Cl and C2 slides with respect to said pulley system.

The first diamond cable Cl, which descends from the first block 139, first runs along the return pulley 137, then the first pulley 130, partially winds on a second block 139 'and finally goes up towards the first block 139.

Similarly, the second diamond cable C2, which descends from the block 139, first runs along the return pulley 138, then the second pulley 131, partially winds on the second block 139 'and finally goes up towards the first block 139.

According to said third embodiment, with reference to Figures 24-26, the excavation system comprises a second system of pulleys and a third system of pulleys, included in the excavation probe 110, to allow the sliding of a third diamond cable C3 and of a fourth diamond cable C4, each of which can be rolled up / unwound respectively on a first pair of blocks RC3, RC3 ', and on a second pair of blocks RC4, RC4', and is driven by a hydraulic motor 140.

Each pair of blocks comprises a first block RC3, RC4 and a second block RC3 ', RC4', where the first block of each pair RC3, RC4 is movable, depending on the depth reached by the excavation probe 110, between an initial position, in which it is inside the well, at a first distance from the well entrance, at a final position, in which it is or inside the well, at a second distance from the well entrance, less than said first distance, or on the surface, at a third distance from the entrance to the well. On the other hand, the second block RC3 ', RC4' of each pair is on the surface, at a predetermined distance from the entrance to the well.

The second pulley system comprises a first pulley 121 and a second pulley 122, each of which rotates respectively on a first rotation axis A1 and on a second rotation axis A2, where said two rotation axes are parallel (fig. 24) .

When rotated by the hydraulic motor 140, the third diamond cable C3, which descends from the first pair of blocks RC3 and RC3 ', partially winds on said first pulley 121, goes up towards the second pulley 122, partially winds said second pulley, it descends further on said first pulley 121, partially winds on said first pulley, and finally rises towards said first pair of blocks RC3, RC3 '(fig. 25).

In particular, the first pulley 121 is divided into a first part and a second part by a central circumferential projection 121A so that, when the third diamond cable C3 partially winds on said first pulley 121 for the first time and for the second time, is in contact with the first part and the second part respectively.

The third pulley system comprises a first pulley 123, a second pulley 124 and a third pulley 125 (Figs. 24-26).

The first pulley 123 and the third pulley 125 of the third pulley system rotate on the first axis of rotation A1, in the opposite direction to the direction of rotation of the first pulley 121 of the second pulley system, and are positioned at the sides of the latter. The second pulley 124 rotates on a third axis of rotation A3, which is parallel to the first axis of rotation A1 and to the second axis of rotation A2.

When rotated by the hydraulic motor 140, the fourth diamond cable C4, which descends from the second pair of blocks RC4 and RC4 ', partially winds on said first pulley 123, goes up towards the second pulley 124, partially winds on said second pulley , descends on said third pulley 125, partially winds said third pulley, and finally rises towards the second pair of blocks RC4, RC4 '(fig. 25).

The first pulley 121 and the second pulley 122 of the second pulley system and the second pulley 124 of the third pulley system are positioned between two parallel plates Pi and P2 and fixed below the casing of the hydraulic motor 140 (fig. 26).

With reference to the transmission of motion from the hydraulic motor 140 to the second pulley system and to the third pulley system, said hydraulic motor 140 can transmit the motion to a first toothed wheel Ri which meshes with a second toothed wheel R2, on which it is provided the second pulley 124 of the third pulley system, and in turn the second toothed wheel R2 meshes with a third toothed wheel R3 on which the second pulley 122 of the second pulley system is provided (Fig. 27). The motor transmits motion to the first toothed wheel R1 in such a way that the second toothed wheel R2 rotates in the opposite direction to that of said first toothed wheel RI and that the third toothed wheel R3 rotates in the opposite direction to that of the second toothed wheel R2, i.e. in the same direction as the first toothed wheel RI.

Furthermore, the excavation probe 110 comprises a controlled hydrodynamic cavitation device 141 for generating cavitation bubbles in such a way as to facilitate excavation.

An advantage is given by the fact that in the event of a scheduled replacement or breakage of a diamond cable, its replacement saves time, since no excavation battery has to be removed.

Advantageously, by means of this excavation system, it is possible to monitor the state of each diamond cable.

Finally, figures 28, 29, 30 schematically show one or more slots dug in the subsoil in correspondence with an excavation plant.

Figures 28 and 29 show a slot excavated in the subsoil having a substantially triangular and substantially rhombic shape respectively, while Figure 30 shows a plurality of slots excavated in the subsoil of substantially rhombic shape.

Advantageously, as already mentioned, regardless of the embodiment, with the system of the present invention it is possible to obtain a radiant surface in the subsoil at the end of a well for the exploitation of geothermal energy by creating one or more cracks in the subsoil

Finally, advantageously, any limestone formations inside the crack dug in the subsoil can be easily removed, first by extracting the water delivery and steam return pipes, introduced after digging the crack and removing the excavation system, and then use the excavation system again to restore the transmittance of the crack walls.

The present invention has been described by way of illustration, but not of limitation, according to its preferred embodiments, but it is to be understood that variations and / or modifications may be made by those skilled in the art without thereby departing from the relative scope of protection, as defined from the attached claims.

Claims (18)

CLAIMS 1. Excavation system for the excavation of a well and / or for the creation of one or more cracks (F) in the subsoil to be used as radiant surfaces for the exploitation of geothermal energy, called excavation system comprising: - at least one drilling arm (1, 1 '; 100) for drilling the ground along the axial direction of said drilling arm, said drilling arm having a first end and a second end, opposite to said first end, - at least one excavation probe (10, 10 '; 110) having a first end coupled to said first end of said at least one drilling arm (1, 1'; 100), and a second end, opposite to said first end, - actuation means (25; 140) to actuate said excavation probe; - mobile cutting means (2; Cl, C2) for cutting rock layers in such a way as to create a gap (F) in the subsoil, and - actuation means (12; 130, 131, 132, 133, 134, 135, 136) to actuate said movable cutting means (2; Cl, C2). 2. Excavation system according to the preceding claim, characterized in that it comprises a first drilling arm (1) and a second drilling arm (1 '), a first excavation probe (10) and a second excavation probe (10 '), each of which is coupled to the first end of a respective drilling arm (1, 1'), in that said drive means (25) are connected to the second end of each drilling arm (1, 1 ') , said actuation means (25) also being directing means for directing each excavation probe (10, 10 '), in that said mobile cutting means (2) comprise a diamond cable (20) slidingly coupled with said first excavation probe excavation (10) and with said second excavation (10 '); said diamond cable (20) extending along said drilling arms (1, 1 ') and between said drilling arms, and by the fact that said excavation system comprises a pulley (32) arranged on the surface, around which said diamond cable ( 20) flows; said pulley (32) being movable with respect to the well inlet between an initial position, in which it is external to the well, at a first predetermined distance from the well inlet, to a final position, in which it is either external to the well, to a second distance from the well inlet, where said second distance is less than said first predetermined distance, or inside the well itself; where said drilling arms (1,1 ') and said cutting means (2) cooperate with each other to crush rock layers in such a way as to create said crack (F) in the subsoil. Excavation system according to the preceding claim, characterized in that each excavation probe (10, 10 ') is equipped with a respective pulley (120, 120') for said diamond cable (20), and in that said means drive (12) for said cutting means (2) comprise at least one of said pulleys (120, 120 '), where said at least one pulley (120, 120') is a driving pulley; said excavation system preferably comprising two return pulleys (13, 13 '), each of which is arranged on a respective drilling arm (1, 1'). 4. Excavation system according to claim 2 or 3, characterized in that respective drilling means (11, 11 ') are coupled on the second end of each excavation probe (10, 10'), in that said drilling means (11, 11 ') are equipped with one or more respective holes or openings (HA, 11Ά) to allow a quantity of water to escape from them and drag the crushed rock debris towards the surface; each drilling arm (1, 1 ') having the second end connected to a water pump (30), said water pump (30) pumping water into said drilling arms (1, 1'), by the fact that each excavation probe (10, 10 ') comprises a hydraulic motor for driving said drilling means (11, 11'). 5. Excavation system according to claim 4, characterized in that said drilling means (11,11 ') are equipped with one or more projections (11B); at least one relief (11B) preferably comprising a piezoelectric or sonodoto transducer (433). 6. Excavation system according to claim 4 or 5 characterized in that said drilling means (11, 11 ') are removably coupled to the second end of the respective excavation probe (10, 10'). Excavation system according to any one of claims 2-6, characterized in that each excavation probe (10, 10 ') comprises a respective first part (10A, 10'A) and a respective second part (10B, 10B' ), as well as a respective joint (15,15 ') which connects said two parts. Excavation system according to any one of claims 2-7, characterized in that each excavation probe (10, 10 ') comprises a respective guiding element (16, 16') to maintain the excavation probe itself in a correct location when the excavation system is in use; each excavation probe (10, 10 ') preferably comprising respective detection means (14, 14') for determining the position of the excavation probe itself. Excavation system according to any one of claims 2-8, characterized in that said diamond cable (20) comprises one or more inserts (20A) arranged on said diamond cable in such a way as to be spaced from each other; at least one insert (20A) preferably comprising a piezoelectric or sonodoto transducer (43). 10. Excavation system according to claim 1, characterized in that said mobile cutting means (2, Cl, C2) for cutting rocky layers comprise a first diamond cable (Cl) and a second diamond cable (C2), in that said actuation means (12, 130, 131, 132, 133, 134, 135, 136) to actuate said movable cutting means (Cl, C2) comprise an articulated quadrilateral (130, 131, 132, 133, 134, 135, 136) which includes: - a first pulley system (130, 131) for said diamond cables (Cl, C2), each of which can be rolled up / unwound on a first block (139), said first pulley system (130, 131) comprising a first pulley (130) and a second pulley (131), arranged along a first axis (X), each of which rotates on a second axis orthogonal to said first axis (X), - a guide element (136) arranged centrally between said first pulley (130) and said second pulley (131), - a first pair of arms (132, 133) for said first pulley (130) and a second pair of arms (134, 135) for said second pulley (131), where the arms of each pair have a first end hinged on a respective pulley and the second end pivoted slidingly on said guide element (136) in such a way that said two pulleys (130, 131) pass from an initial position, in which the arms of each pair are aligned along a first direction and each arm of the first pair is substantially in contact with a respective arm of the second pair, at a final position, in which each arm of the first pair is aligned with a respective arm of the second pair along a second direction, orthogonal to said first direction, and the arms of each pair are substantially in contact with each other; said excavation system preferably comprising a respective return pulley (137, 138) for each diamond cable (Cl, C2). 11. Excavation system according to the preceding claim, characterized in that said excavation probe (110) comprises: - a second pulley system (121, 122) and a third pulley system (123, 124, 125) to allow the sliding of a third diamond cable (C3) and a fourth diamond cable (C4) respectively, where said second pulley system (121, 122) comprises a first pulley (121) and a second pulley (122), each of which rotates respectively on a first axis of rotation (A1) and on a second axis of rotation (A2), called two axes of rotation being parallel, e said third pulley system (123, 124, 125) comprises a first pulley (123), a second pulley (124) and a third pulley (125); the first pulley (123) and the third pulley (125) of said third pulley system (123, 124, 125) rotating on said first axis of rotation (A1) in the opposite direction to the direction of rotation of the first pulley (121) of the second pulley system (121, 122); said first pulley (123) and said third pulley (125) of the third pulley system (123, 124, 125) being positioned laterally to said first pulley (121) of the second pulley system (121, 122); the second pulley (124) of the third pulley system (123, 124, 125) rotating on a third axis of rotation (A3), parallel to said first axis of rotation (A1) and to said second axis of rotation (A2); - a first pair of blocks (RC3, RC3 ') on which said third diamond cable (C3) can be rolled up / unwound at least partially, comprising a first block (RC3) and a second block (RC3'); - a second pair of blocks (RC4, RC4 ') on which said fourth diamond cable (C4) can be rolled up / unwound at least partially, comprising a first block (RC4) and a second block (RC4'), where the first block (RC3, RC4) of each pair (RC3, RC3 '; RC4, RC4') is mobile between an initial position, in which it is inside the well, at a first distance from the well entrance, to a final position, in which it is either inside the well, at a second distance from the well entrance, where said second distance is less than said first distance, or on the surface, at a third distance from the well entrance, and said second block (RC3 ', RC4') of each pair (RC3, RC3 '; RC4, RC4') is on the surface, at a predetermined distance from the well entrance; and by the fact that said actuation means (25, 140) comprise a hydraulic motor (140) to actuate said third diamond cable (C3) and said fourth diamond cable (C4); said first pulley (121) of the second pulley system (121, 122) preferably being equipped with a central circumferential projection (121A) which divides it into a first part and a second part, so that the third diamond cable (C3) is wound in an orderly manner on said first pulley (121). Excavation system according to the previous claim, characterized in that said excavation probe (110) comprises a first toothed wheel (RI), a second toothed wheel (R2) on which the second pulley (124) of the third system is coupled of pulleys (123, 124, 125), said second toothed wheel (R2) being engaged with said first toothed wheel (RI), and a third toothed wheel (R3) on which the second pulley (122) of the second pulleys (121, 122), said third toothed wheel (R3) being engaged with said second toothed wheel (R2), and by the fact that said hydraulic motor (140) transmits motion to said first toothed wheel (RI) in such a way that the second toothed wheel (R2) rotates in the opposite direction to that of said first toothed wheel (RI), and that the third toothed wheel (R3) rotates in the opposite direction to that of said second toothed wheel (R2). Excavation system according to any one of the preceding claims, characterized in that said at least one excavation probe (10, 10 '; 110) further comprises at least one controlled hydrodynamic cavitation device (29A, 29A', 29B, 29B '; 141) to generate cavitation bubbles, in particular pico-bubbles, nano-bubbles and micro-bubbles. Excavation system according to any one of claims 3-9, characterized in that each excavation probe (10, 10 ') comprises a respective first controlled hydrodynamic cavitation device (29A, 29A') and a second respective cavitation device controlled hydrodynamic (29B, 29B '), by the fact that each first controlled hydrodynamic cavitation device (29A, 29A') is positioned between the first end of the respective excavation probe (10, 10 ') and a point of said excavation probe (10, 10 ') in correspondence with which a respective pulley (120, 120') for the diamond cable (20) is coupled, and each second controlled hydrodynamic cavitation device (29B, 29B ') is positioned between said point and the second end of the respective excavation probe (10, 10 '), and by the fact that a pipe (28) equipped with nozzles (28A) connects the first controlled hydrodynamic cavitation device (29A) of the first excavation probe (10) to the first arranged controlled hydrodynamic cavitation (29A ') of the second excavation probe (10') so that, when said first controlled hydrodynamic cavitation devices (29A, 29A ') are in use, said nozzles (28A) inject the cavitation on the diamond cable (20) and on the rock layers; said pipe (28) comprising at least two rigid pipes connected to each other by means of a first connecting element (27) and being connected to each first controlled hydrodynamic cavitation device (29A, 29A ') of the excavation probes (10, 10') by means of a respective second connecting element (277, 277 '); each second connecting element (277, 277 ') having one end connected to a respective outlet of a first controlled hydrodynamic cavitation device (29A, 29A') and the other end connected to said pipe (28); said first connecting element (27) and said second connecting elements (277, 277 ') allowing the pipe (28) to pass from a first position, in which said two rigid pipes are substantially vertical and in contact with each other, to a second position, in which said two rigid pipes are substantially aligned horizontally. 15. Excavation system according to the preceding claim, characterized in that it comprises one or more blocks (40) arranged on the surface, and in that said pipe (28) is connected to said one or more blocks (40) by means of one or more cables (41), each of which can be rolled up / unwound at least partially on said blocks (40). 16. Excavation system according to claim 14 or 15, characterized in that each first controlled hydrodynamic cavitation device (29A, 29A ') and each second controlled hydrodynamic cavitation device (29B, 29B') comprises a hydrodynamic motor (35) , rotating around its axis of rotation (35A), a rotor (36), a stator (37) inside which said rotor is positioned. 17. Excavation system according to claim 16 (when dependent on claim 5), characterized in that said second controlled hydrodynamic cavitation device (29B, 29B ') further comprises a rotating head (38), integral with the rotor (36), wherein said rotating head (38) is equipped with a plurality of injectors (39) to inject cavitation bubbles outside through the holes or openings (H A, 11A ') of the perforation means (11, 11'). 18. Excavation system according to any one of claims 16-17, characterized in that the hydrodynamic motor (35) is inside a casing (34), and in that one or more magnetic shock absorber bearings (38) are positioned on said casing (34) to cushion the vibrations to which said hydrodynamic motor (35) is subject when the excavation system is in use.