ITRM20100318A1 - PROCEDURE FOR IMPLEMENTATION IN THE SUBSUBLE OF LAYERABLE ARTIFICIAL PERMEABLES FOR THE EXPLOITATION OF GEOTHERMAL ENERGY. - Google Patents

Description

PROCEDURE FOR THE CREATION OF ARTIFICIAL PERMEABLE LAYERS IN THE SUBSOIL FOR THE EXPLOITATION OF GEOTHERMAL ENERGY

The present invention relates to the renewable energy sector, such as that of geothermal energy, and refers to a process for the construction in the subsoil of crushed areas or artificial permeable layers for the exploitation of geothermal energy.

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 air conditioning systems heat or cool an environment, for example a house, at the request of the user depending on the current season.

These air conditioning systems can take the temperature of the external air or that of the ground on which the dwelling is located as a reference temperature.

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 air 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 excavation made to execute 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 about 2000 square meters. 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 it is introduced. 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, the only technique to increase the radiant surface consists in making a well, digging to the desired depth, and filling it with water, on which pressure is exerted by means of 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.

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

The purpose of the present invention is to overcome said disadvantages, providing a process for making a permeable layer in the subsoil comprising a crushed zone or a plurality of crushed zones communicating with each other, through one or more fractures, in such a way as to increase the surface radiant for the exploitation of geothermal energy, where each broken zone is an artificial permeable layer.

Therefore, the specific object of the present invention is a process for the realization of an artificial permeable layer for the exploitation of thermal energy, which process comprises the following steps:

A) digging a well up to a certain depth with respect to the surface by means of excavation means, with simultaneous jacketing of the wall of the well by means of a jacket tube, said jacket tube comprising a plurality of elements which can be coupled together in a removable way;

B) remove the excavation means;

C) removing at least one element of said jacket tube of the well leaving a space between the lower end of said jacket tube and the bottom of the well;

D) inserting in said jacket tube at least one projectile containing at least one explosive charge;

E) triggering said at least one explosive charge of said at least one projectile;

F) to detonate, in the space between the lower end of said jacket tube and the bottom of the well, said at least one explosive charge of said at least one projectile with consequent creation of a crushed zone in the subsoil which creates said artificial permeable layer.

According to the invention, steps D) to F) can be repeated at least once.

Still according to the invention, the step of inserting the projectile into the jacket tube can be carried out by leaving said projectile in free fall or by imparting a thrust to it.

Still according to the invention, the projectile can comprise a plurality of explosive charges and said explosive charges can be detonated simultaneously or at different times.

According to another aspect of the invention, after phase F), it is possible to foresee the following phases:

G) establish on the basis of the dimensions of the crushed zone created in the subsoil in phase F) the lateral distance at which to create a further crushed zone so that said further crushed zone is communicating with the previous crushed zone created;

H) repeat steps A) to F) to create a further crushed area at the distance established in step G), where said further crushed area is communicating with the previously created crushed area.

According to the invention, steps G) and H) can be repeated until a desired number of broken zones communicating with each other is obtained.

According to another aspect of the invention, after the creation of a further crushed zone communicating with a previously created crushed zone (phase H)), each crushed zone being provided in proximity to the bottom of a first well and a second well respectively, the following phases may be envisaged:

I) connecting said first and second wells to a pump by means of a respective conduit;

L) inserting into the jacket tube of said first well a projectile having a diameter approximately equal to that of said jacket tube;

M) suck by means of said pump the air underneath said projectile that comes out of said second well, said air passing from said first well to said second well through one or more fractures which make the two crushed areas communicating, and introduce by means of said pump the air sucked in above said projectile so that said projectile undergoes an increase in acceleration.

Still according to the invention it is that after the creation of a plurality of crushed zones communicating with each other, each crushed zone being foreseen near the bottom of a respective well, the following phases can be envisaged:

I) connecting said wells to a pump by means of a respective conduit;

L) inserting into the jacket tube of a well a projectile having a diameter approximately equal to that of said jacket tube;

M) suck the air under said projectile through said pump that comes out of the other wells, passing from the well in which said projectile is inserted to the other wells, through one or more fractures that make the crushed areas communicating, and enter through said pumps the sucked air above said projectile so that said projectile undergoes an increase in acceleration.

Always according to the invention, between the removal phase of an element of the jacket tube (phase C)) and the phase of inserting a bullet into the jacket tube (phase D)), or after the phase of creating a crushed area (phase F)), it is possible to foresee a phase for the insertion of a target or impact element into the jacket tube to allow the projectile to explode at a point between the lower end of the jacket tube and the bottom of the water well.

A further object of the invention is a projectile which, in a first embodiment, can have an elongated shape, and include one or more explosive charges, an electronic control unit that controls the timing of the explosions of said explosive charges, and at least one detonator for said explosive charges connected to said electronic control unit.

Said projectile further comprises a rigid protection and an insulating layer, underneath said rigid protection, which can be a layer of glass foam or glass wool or rock wool or ceramic or other insulating material for high temperatures.

In said first embodiment, the projectile has on its external surface a plurality of fins arranged radially, each having a length such as to come into contact with the internal surface of the jacket tube of a well into which it is inserted.

According to the invention, said plurality of fins can be arranged in groups, each of which is located at a different height on the outer surface of the bullet.

Still according to the invention, a respective detonator can be provided for each explosive charge of the projectile, each of which is connected to said electronic control unit.

Further according to the invention, said projectile can further comprise a pin, having a free end that protrudes from the projectile and the other end that is in contact with the detonator of an explosive charge.

Still according to the invention, the projectile can comprise a disposable propeller, for example a compressed air or solid propellant propeller.

A further object of the invention is a projectile which, in a second embodiment, can have an elongated shape and include one or more explosive charges, an electronic control unit that controls the timing of the explosions of said explosive charges and at least one detonator for said charges explosives connected to said electronic control unit.

Said projectile further comprises a rigid protection and an insulating layer, underneath said rigid protection, which can be a layer of glass foam or glass wool or rock wool or ceramic or other insulating material for high temperatures.

In said second embodiment, the projectile has a diameter approximately equal to that of a jacket tube of a well into which it is inserted.

According to the invention, a respective detonator is provided for each explosive charge of said projectile.

Still according to the invention, said projectile can include a pin having a free end that protrudes from the projectile and the other end that is in contact with the detonator of an explosive charge.

Further according to the invention, said projectile can comprise a disposable thruster, for example a compressed air or solid propellant thruster.

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

Figure 1 schematically shows the step of excavating a well by means of excavation means with simultaneous jacketing of the well by means of a jacket tube comprising a plurality of elements which can be coupled together in a removable way;

figure 2 schematically shows the well dug up to a predetermined depth;

figure 3 schematically shows the well covered by the jacket tube where the excavation means have been removed;

figure 4 shows the dug well of fig. 3 where an element has been removed from the jacket tube in order to leave a space between the lower end of said jacket tube and the bottom of the well;

figure 5 schematically shows the insertion of a projectile into the jacket tube of the well;

figure 6 schematically shows the explosion of the projectile at the bottom of the dug well;

figure 7 schematically shows a shattered zone created on the bottom of the well following the explosion of the bullet;

figure 8 shows, in addition to the crushed area of fig. 7, two further shattered zones created following the explosion of bullets, each inserted in a respective pit, where said shattered zones are communicating with each other;

figure 9 schematically shows the operation of a plant for using the steam extracted from a well other than the one into which water was introduced;

figure 10 shows a longitudinal section of a first embodiment of the projectile of fig. 5;

figure 11 is a cross section of the projectile of fig. 10 inserted in the jacket tube of the well;

Figures 12a and 12b schematically show a target or impact element, respectively in rest and working conditions, which must be inserted into the jacket tube to position itself in the well and detonate the projectile at a different height with respect to the bottom of the well itself;

figure 13 shows a longitudinal section of a variant of the first embodiment of the projectile;

figure 14 is a cross section of a well in which a jacket tube is inserted inside which a tube is inserted to introduce water with a smaller diameter than the jacket tube to allow the steam to escape from the space between the surface external of said water inlet pipe and the internal surface of the jacket pipe; figure 15 shows a longitudinal section of a second embodiment of the projectile;

figure 16 is a cross section of the projectile of fig. 15 inserted in the jacket tube of the well;

figure 17 shows two broken zones communicating with each other, each of which was created on the bottom of a respective well following the explosion of a projectile of fig. 10 inserted in each well, where said wells are connected together so that the air below the projectile of fig. 15 inserted in a first well comes out of the second well to be pumped into the first well in order to generate an air pressure on said projectile.

With reference to figures 1-7, a procedure is envisaged for the realization of artificial permeable layers for the exploitation of thermal energy, which procedure comprises the following phases:

A) digging a well 2 up to a determined depth 6 with respect to the surface 3 by means of excavation means 1, with simultaneous jacketing of the well wall by means of a jacket tube 4, said jacket tube comprising a plurality of elements which can be coupled together in a removable way;

B) remove the excavation means 1;

C) removing at least one element of said jacket tube 4 of well 2 leaving a space between the lower end of said jacket tube 4 and the bottom of well 2;

D) inserting in said jacket tube 4 at least one projectile P containing at least one explosive charge 23;

E) triggering said at least one explosive charge 23 of said at least one projectile P;

F) detonate, in the space between the lower end of said jacket tube 4 and the bottom of well 2, said at least one explosive charge 23 of said at least one projectile P with consequent creation of a crushed area 11 in the subsoil which creates said artificial permeable layer.

As regards the excavation phase of a well (phase A)), the depth 6 of the well 2 with respect to the surface 3 is chosen according to the temperature of the rocky layer useful for exploiting the thermal energy and / or the layer in the subsoil which has a certain mechanical resistance, for example a layer with a lower mechanical resistance, such as that formed by limestone or sandstone.

Still as regards the step of excavating a well (step A)), the excavation means 1 comprise a drill.

In the example described, well 2 is dug in correspondence with an excavation plant 5.

As regards the step of inserting the projectile P into the jacket tube 4 (step D)), said projectile P is left in free fall.

It is evident that to insert the projectile P into the jacket tube 4 of the well 2, said projectile P must have a smaller diameter than the diameter of the jacket tube 4. The fact that the diameter of the projectile P is smaller than that of the jacket tube 4 allows the The air below to flow upwards, towards the surface 3, thus avoiding that the same air is compressed.

In its first embodiment, the projectile P provides on its external surface a plurality of fins 22 arranged radially having a length such as to come into contact with the internal surface of the jacket tube 4, so that the projectile P is coaxial to the jacket tube 4 in which it is inserted.

Thus configured, the bullet reaches the bottom of shaft 2 in a few seconds.

The P bullet shown in figure 11 has three groups of fins 22, and each group is positioned at a different height on the outer surface of the P bullet.

It is evident that the greater the diameter of the shaft 2, the greater the diameter of the jacket tube 4 and the greater the diameter of the projectile P. Consequently, said projectile P can contain a greater explosive charge and this allows to obtain an area crushed 11 wider and therefore a greater radiant surface to be used for the exploitation of geothermal energy.

As regards the firing phase of the at least one explosive charge 23 of the projectile (phase E)), said firing is controlled by an electronic control unit 33 provided in the projectile.

The electronic control unit 33 controls the explosions of the explosive charges 23 according to a predetermined timing.

For this purpose, for each explosive charge 23 there is a detonator connected to the electronic control unit 33.

In the example described, the projectile P has an elongated shape and comprises two explosive charges, a first explosive charge 23 and a second explosive charge 23, each of which is activated by a respective detonator, a first impact detonator 29 for the first explosive charge 23 and a second detonator 29 for the second explosive charge 23 (fig.

10).

Therefore, the electronic control unit 33 can command the explosion of the second charge 23 in a different time from the explosion of the first charge 23.

In particular, the P bullet can be divided into three parts: a head 30, a body 31, and a tail 32.

In the head 30 of the projectile P there is a pin 28 having a free end which protrudes from said head 30 and an end which is in contact with the first detonator 29 so that when the free end of said pin 28 impacts against the bottom of shaft 2, the other end activates the first detonator.

As already mentioned, although not illustrated in the figures, the number of explosive charges inside the P projectile can be any, even greater than two. For example, it is possible to foresee that the projectile P comprises three charges: a first charge, a second charge and a third charge between said first and second charge. In this case, if the first charge and the second charge explode at the same time, slightly before the third charge, it is possible to obtain a greater exploding force in correspondence with said third charge, thus generating a larger shattered area at a ™ specific height. This can be useful when you want to work on a rock layer at a specific depth which is different from the depth 6 at which the bottom of well 2 is located.

Furthermore, the projectile is equipped with a rigid protection 24 which acts as a jacket for the projectile itself and with an insulating layer 21, underneath said rigid protection 24 (fig. 11).

The rigid protection 24, together with the fins 22, guarantees a rectilinear movement of the projectile P during the fall inside the jacket tube 4, so as to improve the aerodynamic characteristics and to avoid the explosion of the explosive charges 23 as a result of sudden movements and / or impacts against the jacket tube 4

The insulating layer 21 can be a layer of glass foam, glass wool, rock wool, ceramic or other insulating material for high temperatures to prevent the explosive charges 23 from accidentally exploding as a result of high temperatures that can be found in depth.

In a variant shown in fig. 13, the projectile is equipped with a disposable thruster 31, for example a compressed air thruster or a solid propellant thruster. In this variant, a tank 35 connected to said thruster 31 is provided in the projectile.

Therefore, as regards the step of inserting the projectile into the jacket tube 4 (step D)), said projectile is pushed by said thruster 31 to lose, as well as by the effect of gravity.

According to the invention, after phase F), it is possible to foresee the following phases:

G) establishing on the basis of the dimensions of the crushed zone 11 created in the subsoil the lateral distance at which to realize a further crushed zone 11 so that said further crushed zone 11 communicates with the previously created crushed zone 11;

H) repeating steps A) to F) for the creation of a further crushed zone 11 at the distance established in step G) so that said further crushed zone 11 communicates with the previously created crushed zone 11.

These phases G) and H) can be repeated until a desired number of crushed zones 11 communicating with each other are obtained.

In the example described, three broken zones 11 communicating with each other are shown (fig. 8).

Once said crushed zones 11 have been made, it is possible to introduce water or other fluid into one or more of said wells 2 so that said water or said fluid escapes vaporized and under pressure from wells different from those in which said water or said fluid has been entered.

Advantageously, in this way, it is possible to use water or vaporized and pressurized fluid to obtain mechanical and / or electrical and / or thermal energy.

Figure 9 shows a plant that uses the steam that comes out of two wells placed on the side of the well into which water is introduced.

This plant comprises a condensation tower 15 and an apparatus 17 for the transformation of thermal energy into electrical energy which is supplied to the users by means of an electrical distribution line 18.

Even with a single well 2 it is possible to use water or vaporized and pressurized fluid to obtain mechanical and / or electrical and / or thermal energy.

For this purpose, it is sufficient to insert in this well 2, a pipe 26 for the introduction of water in such a way that the water or fluid vaporized and under pressure to obtain mechanical and / or electrical energy and / or thermal exit from the space between said pipe 26 for the introduction of water and the jacket pipe 4 of well 2 (fig. 14).

In this specific case, both the water inlet pipe 26 and the jacket pipe 4 are coated with an insulating layer, respectively a layer 27 and a layer 47.

According to the invention that is described, between the step of removing an element of the jacket tube 4 (phase C)) and the step of inserting a bullet into the jacket tube 4 (phase D)), it is possible to foresee a phase for the insertion in the jacket tube 4 of a target or impact element 12 to allow the projectile P to explode at a point between the lower end of the jacket tube 4 and the bottom of the shaft 2 (figs. 12a, 12b ).

In particular, said impact element 12 can be inserted in the jacket tube 4 after the explosion of the first projectile P so that the second projectile P can explode in a different point from the explosion of the first projectile P, as the shattered area 11, formed following the explosion of the first projectile P, may have an impact surface that is not adequate for the explosion of the second projectile P. In fact, the space between the lower end of the jacket tube 4 and the bottom of the well 2 can be obstructed by the rocks shattered by the explosion of the first bullet P. In this case, one or more further elements of the jacket tube 4 are removed, so as to leave a space between the lower end of said jacket tube 4 and said crushed rocks, before the second projectile P is inserted into the jacket tube 4.

In a second embodiment, a projectile Pâ € ™ is provided which is devoid of fins 22 and has a diameter approximately equal to that of the jacket tube 4 into which it is inserted (figs. 15, 16).

Therefore, said projectile Pâ € ™, having a diameter approximately equal to that of the jacket tube 4, is capable of containing a greater quantity of explosives than that contained in the first embodiment of the projectile and in its variant, previously described, and of consequently it allows to realize crushed zones 11 of greater amplitude.

The use of said Pâ € ™ projectile is reserved for the case in which the crushed zones 11, communicating with each other, have already been created near the bottom of respective wells 2 through the explosion of a P projectile of the type described in the first embodiment or in the variant of said first embodiment.

In the example illustrated in fig. 17, two broken zones 11 are shown communicating with each other, by means of one or more fractures, each created on the bottom of a respective well 2.

The two wells are connected on the surface by means of a respective duct to a pump 36 in such a way that the air below the projectile Pâ € ™, inserted in a first well 2, passes into the second well 2 through said one or more fractures, and channel into the conduit that connects said second well to said pump 36.

The pump 36 sucks in said air and introduces it into the first well 2, generating an air pressure on the projectile Pâ € ™ itself.

In this way, the acceleration of the Pâ € ™ projectile, already in free fall in the first shaft 2, is increased, without the need to provide a propeller inside said projectile.

In other words, after the creation of a second crushed zone 11, communicating with a first crushed zone (phase H)), each crushed zone being foreseen near the bottom of a first and a second well respectively, the following phases are foreseen :

I) connecting said first and second wells 2 to a pump 36 by means of a respective conduit;

L) inserting into the jacket tube 4 of said first well 2 a projectile Pâ € ™ having a diameter approximately equal to that of said jacket tube 4;

M) suck by means of said pump 36 the air below said projectile Pâ € ™ that comes out of said second well 2, passing from the first well to the second well 2 through one or more fractures which make the two crushed areas 11 communicating, and enter by means of said pump 36 the air sucked above said projectile Pâ € ™ so that said projectile undergoes an acceleration.

Advantageously, as already mentioned, with the process of the present invention it is possible to obtain a radiant surface for the exploitation of geothermal energy by creating a crushed zone or a plurality of crushed zones communicating with each other.

A second advantage is given by the possibility of creating crushed areas and non-fractures by means of this procedure as in the case of the prior art, consequently increasing the radiant surface for the exploitation of geothermal energy.

The present invention has been described by way of illustration, but not of limitation, according to a preferred embodiment thereof, 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 by the appended claims.

Claims (17)

CLAIMS 1. Process for the construction of an artificial permeable layer in the subsoil for the exploitation of geothermal energy, which process includes the following phases: A) digging a well (2) by means of excavation means (1), with simultaneous jacketing of the wall of said well by means of a jacket tube (4), said jacket tube (4) comprising a plurality of elements which can be coupled together in a removable way; B) remove the excavation means (1); C) removing at least one element of said jacket tube (4) of the well (2) leaving a space between the lower end of said jacket tube (4) and the bottom of the well (2); D) inserting in said jacket tube (4) a projectile (P) comprising at least one explosive charge (23); E) igniting said at least one explosive charge (23) of said at least one projectile (P); F) detonate, in the space between the lower end of said jacket tube (4) and the bottom of the well (2), said at least one explosive charge (23) of said projectile (P) with consequent creation of a crushed area (11) which creates said artificial permeable layer. 2. Process according to claim 1, characterized in that steps D) to F) are repeated at least once. 3. Process according to one of the preceding claims, characterized in that as regards the step of inserting the projectile (P) into the jacket tube (4) (phase D)), it is carried out leaving said projectile (P) in free fall, or giving the bullet (P) a push. 4. Process according to one of the preceding claims, characterized in that said projectile (P) comprises a plurality of explosive charges (23), said explosive charges (23) being able to be detonated simultaneously or at different times. 5. Process according to one of the preceding claims, characterized in that after step F), the following steps are envisaged: ( 11) previous created; H) repeating steps A) to F) for the creation of a further crushed zone (11) at the distance established in step G), said further crushed zone (11) being communicating with the previously created crushed zone (11); said phases G) and H) being able to be repeated until a desired number of crushed zones (11) communicating with each other are obtained. 6. Process according to claim 5, characterized in that after the creation of a further crushed zone (11) communicating with a previously created crushed zone (phase H)), each crushed zone (11) being provided in proximity to the bottom respectively of a first well (2) and a second well (2), the following phases are foreseen: I) connecting said first and second wells (2) to a pump (36) by means of a respective conduit; L) inserting into the jacket tube (4) of said first well (2) a projectile (Pâ € ™) having a diameter approximately equal to that of said jacket tube (4); M) sucking through said pump (36) the air below said projectile (Pâ € ™) that comes out of said second well (2), said air passing from said first well to said second well through one or more fractures that make communicating the two broken zones (11), and introducing through said pump (36) the air sucked above said projectile (Pâ € ™) so that said projectile (Pâ € ™) undergoes an increase in acceleration. 7. Process according to claim 6, characterized in that after the creation of a plurality of crushed zones (11) communicating with each other, each crushed zone (11) being provided in proximity to the bottom of a respective well (2), are provided the following steps: I) connecting said wells (2) to a pump (36) by means of a respective conduit; L) inserting into the jacket tube (4) of a well (2) a projectile (Pâ € ™) having a diameter approximately equal to that of said jacket tube (4); M) suck by means of said pump (36) the air below said projectile (Pâ € ™) that comes out of the other wells (2), passing from the well in which said projectile is inserted to the other wells, through one or more fractures which make the shattered zones (11) communicating, and through said pump (36) to introduce the air sucked above said projectile (Pâ € ™) so that said projectile (Pâ € ™) undergoes an increase in acceleration. 8. Process according to one of the preceding claims, characterized in that, between the step of removing an element of the jacket tube (4) (step C)) and the step of inserting a projectile (P) into the jacket tube (4) (phase D)), or after the phase of creating a crushed area (11) (phase F)), there is a phase for the insertion of a target or impact element into the liner tube (4) (12) to allow the projectile (P) to explode in a point between the lower end of the jacket tube (4) and the bottom of the well (2). 9. Projectile (P) to carry out the process according to one of the preceding claims 1-8, characterized in that it has an elongated shape and comprises one or more explosive charges (23), an electronic control unit (33) which controls the timing of the explosions of said explosive charges (23) and at least one detonator (29) for said explosive charges (23) connected to said electronic control unit (33); on the external surface of said projectile (P) there is provided a plurality of fins (22) arranged radially, each having a length such as to contact the internal surface of a jacket tube (4) of a well (2) in which à ̈ inserted; said projectile (P) further comprising a rigid protection (24) and an insulating layer (21), underlying said rigid protection (24); said insulating layer (21) being a layer of glass foam or glass wool or rock wool or ceramic or other insulating material for high temperatures. Projectile (P) according to claim 9, characterized in that said plurality of fins (22) is arranged in groups, each of which is located at a different height on the external surface of the projectile (P). Projectile (P) according to one of claims 9 or 10, characterized in that a detonator (29) is provided for each explosive charge (23). 12. Projectile (P) according to one of claims 9-11, characterized in that it comprises a pin (28), having a free end that protrudes from the projectile (P) and the other end that is in contact with the detonator (29) of an explosive charge (23). Projectile (P) according to one of claims 9-12, characterized in that it comprises a disposable thruster (31), for example a compressed air or solid propellant thruster. 14. Projectile (Pâ € ™) to carry out the process according to one of claims 6-8 (when dependent on claims 6 or 7), characterized in that it has an elongated shape and comprises one or more explosive charges (23), a control unit electronics (33) which controls the timing of the explosions of said explosive charges (23) and at least one detonator (29) for said explosive charges (23) connected to said electronic control unit (33); said projectile (Pâ € ™) having a diameter approximately equal to that of a jacket tube (4) of a well (2) in which it is inserted; said projectile (Pâ € ™) further comprising a rigid protection (24) and an insulating layer (21), underlying said rigid protection (24); said insulating layer (21) being a layer of glass foam or glass wool or rock wool or ceramic or other insulating material for high temperatures. 15. Projectile (Pâ € ™) according to claim 14, characterized in that a detonator (29) is provided for each explosive charge (23). 16. Projectile (P ') according to one of claims 14-15, characterized in that it comprises a pin (28) having a free end that protrudes from the projectile (Pâ € ™) and an end that is in contact with the detonator ( 29) of an explosive charge (23). Projectile (Pâ € ™) according to one of claims 14-16, characterized in that it comprises a disposable thruster (31), for example a compressed air or solid propellant thruster.