Downhole seismic exploration device and apparatus.

DESCRIPTION

The present invention relates to an apparatus and geophysical exploration devices and particularly, although not exclusively, to downhole seismic tools to be lowered by a drilling well that extends into the earth and temporarily secured in the well in a location. desired to receive waves that travel through the underground formations to analyze the underground structure.

Downhole seismic exploration tools for geophysical exploration are well known in the art. Such tools are generally elongated in shape and typically include a seismic detector, often referred to as a geophonic, and a mechanical insurer to temporarily secure the tool to the well wall in desired locations to collect seismic waves or disturbances that travel the earth.

When a geophysical exploration with said seismic exploration tool must be carried out down the hole, the tool is first descended into a drillhole using a cable and temporarily fixed to the wall of the well at a desired depth. Seismic waves or disturbances are created, for example, by means of a pneumatic pistol, and are collected after traveling on the ground by the seismic detector provided inside the tool that is temporarily secured to the wall of the borehole. . Then, the tool is released from its fixation, sent to another depth and again temporarily secured to the wall of the well for another measurement. In this way, the tool is vertically slid along the well, taking measurements at different depths while the tool is temporarily secured to the wall of the drill hole.

A typical seismic exploration tool, well down from the prior art, is of an extremely large size, particularly in length that can be up to 6 meters and weigh as much as 17 kilograms. The main reason for this size is that the prior art tool uses a mechanical fixing device.

As noted above, the tool must be temporarily secured to the well wall and for this purpose the tool must be provided with a fixing device.

In the prior art tool, a mechanical fixing device having pivotally movable arms is normally used. The use of such a mechanical fixing device necessarily entails a high size and weight of the tool.

It is therefore a main object of the present invention to alleviate the disadvantages of the prior art described above and to provide an improved downhole sessic apparatus and device.

Another object of the present invention is to provide a seismic scanning device of significantly smaller size and lighter weight compared to the typical prior art apparatus.

Another object of the present invention is to provide a well-bottomed sessic scanning device suitable for use in an apparatus in the form of an ordered assembly, having a plurality of such devices arranged in series along a cable and by means of which the assembly of Devices can be temporarily secured to the wall of the well, while allowing simultaneous measurement in multiple locations.

A further object of the present invention is to provide a two-sided seismic scanning device comprising a sensor package that includes a seismic detector and a carrier connected to a cable that carries the sensor package acoustically decoupled from the carrier and substantially located therein, thus allowing an increase in the signal-to-noise ratio of the detected signal.

Another main object of the present invention is to provide a seismic exploration device well down easy to handle and reliable operation.

In accordance with one aspect of the present invention, a two-sided downhole sessic scanning device is provided, which generally comprises a sensor package containing at least one semesic or geophone detector and a carrier connected to a cable carrying the sensor package substantially inside and acoustically decoupled from it.

In the preferred embodiment, the sensor package is generally cylindrical in shape and the carrier is generally catamaran-shaped, so that the sensor package can be carried by the carrier between the two pieces.

In the preferred embodiment, closed rings are provided between the carrier and the sensor package to decouple them acoustically between each other. With this structure, the effects of the so-called tube and cable waves, which run along the well longitudinally, can be almost completely eliminated, because only the carrier is subjected to said tube and cable waves.

Although a main cable can be loosened after fixing an orderly set of seismic scanning devices in its position, a cable wave could be produced that would be transmitted through the assembly; however, the acoustically decoupled structure of the present invention avoids the effect of said cable wave on the sensor.

In accordance with another aspect of the present invention, a seismic scanning device is provided downstream that includes a magnetic insurer that can be activated ("ON") and deactivated ("OFF") to thereby secure and release the tubing device from the well.

Preferably, said magnetic insurer is provided inside the sensor package that is part of the seismic scanning device downstream of two parts. In the activated condition (“ON”), the magnetic flux is radiated out of the sensor package thus allowing the formation of a closed magnetic circle through the well tubing. On the other hand, in the deactivated condition (“OFF”) the magnetic flux is short-circuited, thus preventing the magnetic flux from radiating out of the sen2 packet.

000 730 Sr.

In addition, the sensor package preferably contains an electronic module to control the operation of the magnetic insurer and at least partially process the signals received by the seismic detector.

A bimorph piezo stirrer element is advantageously included in the sensor package to vibrate the sensor package and verify its fixation before acquiring semic data.

In accordance with a third aspect of the present invention, an orderly set of downhole seismic scanning devices is provided, secured and spaced along a cable and having a provision to be temporarily fixed to the wall of a drilling well and arranged to be coupled in parallel to a measurement control unit.

Additional objects and novelties of the present invention would be more apparent when considering the following detailed description of the invention, with reference to the accompanying drawings. Figure 1

It is a schematic illustration showing an offshore geophosic exploration system, in which the present invention is advantageously applied.

Figure 2

It is a schematic illustration of a geophosic ground exploration system advantageously applying the present invention.

Figure 3

It is a front view illustrating the three pulley guide assembly (13) provided in the system of Figure 2.

Figure 4

It is a side elevation view of the guide assembly (13) illustrated in Figure 3.

Figures 5a, 5b and 5c

They are useful schematic illustrations to explain the operation of the guide assembly 13. Figure 6

It is a schematic illustration showing the basal structure of a two-part downhole septic exploration device incorporating the present invention.

Figure 7

It is a schematic view illustrating the front view of the structure illustrated in Figure 6. Figure 8

It is a schematic view taken in cross-section along line II of Figure 6. Figures 9a and 9b

They are schematic cross-sectional views taken along the line II-II indicated in Figure 6, useful for explaining the operation of a fixing section of the device.

Figure 10

It is a schematic illustration showing a specific realization of a two-part downhole septic exploration device according to the present invention.

Figure 11

It is a schematic view in side elevation partially illustrating in cross-section the structure of Figure 10.

Figure 12

It is a schematic cross-sectional view taken along line III-III indicated in Figure 11.

Figure 13

It is a schematic cross-sectional view taken of the long-length IV-IV indicated in Figure 11.

Figure 14

It is a rear end view of the structure illustrated in Figure 11.

Figure 15

It is a schematic perspective view illustrating the downhole seismic scanning device, armed and connected to the cable (64).

Figure 16

It is a schematic perspective view illustrating the cylindrical envelope (49) of the sensor package (44).

Figure 17

It is a schematic perspective view illustrating the components to be placed inside the envelope (49).

Figure 18

It is a schematic illustration showing the connection between the fixing section (56) and the driving section (57).

Figure 19

It is an enlarged schematic view illustrating the detailed structure of the test engine switch section (55).

Figure 20

It is a schematic illustration showing the mechanism of automated closure for the driving section (57).

Figures 21a and 21b

They are useful schematic illustrations to explain the operation of a switch.

Figure 22

It is an enlarged and fragmentary schematic view illustrating particularly the connection between the cable (64) and the carrier (39).

Figures 23 and 24

They are schematic views that illustrate two exemplary combinations of various geophosic scanning devices.

Figure 25

It is a schematic perspective view of the downhole semic scanning device illustrating the provision to protect the cable (64).

Referring now to FIG. 1, a geophoscopic exploration system, of the offshore type in which an ordered set of seismic exploration devices is used downstream according to the present invention, is schematically illustrated.

As illustrated, the scanning system includes a maritime exploration platform (1) that supports a measurement control unit (1a), including a data acquisition device or the like. A well (2) is drilled in the ground below the maritime exploration platform (1), and a tubing (3) is placed in the perforation (2) to define the wall of the drilling well (2).

As is well known to those skilled in the art, the tubing (3) comprises a plurality of cylindrical tubes connected in series end to end. In the illustrated example, it is important that the tubing (3) comprises a ma3

000 730 magnetic terial. The perforation (2) extends through several underground formations, of which only one, the formation 5, is illustrated in Figure 1.

A downhole cable (4) extends downward from the marine exploration platform (1) and into the borehole (2), and the cable (4) has one end connected to the measurement control unit (1a) and the other end connected to a weight (6) that facilitates the downward movement of the cable (4) through the perforation (2).

A plurality of downhole semic scanning devices (7) (five in the illustrated example) is fixed to the cable (4) spaced apart between each device. Also attached to the cable (4), above the plurality of devices for semic scanning (7), a carriage (8) for the acquisition and telemetry of the signals.

Downhole seismic scanning devices can be temporarily secured to the tubing (3) to collect semic waves that have been propagated through the formations. In the illustrated example, some of the devices (7) are secured to the right side wall and others to the left side wall, as shown in the figure. It should be noted that the devices (7) define a generally vertical set and, therefore, data originating from the same semic source can be collected at a plurality of depths at the same time.

An exploratory exploration (10) located far from the maritime exploration platform (1) has a semic source (10a), topically an air gun, which generates semic waves or disturbances. When the semic source (10a) is excited, semic waves are generated that propagate through the underground formations. Some of the semic waves arrive at the ordered set of devices (7) directly after passing through the formations and some of the semic waves reach the set of devices after they have been reflected in the interface between the two formations where there is a change in the aquatic impedance.

In operation, after moving the septic devices down the hole (7) down through the perforation (2) to the desired locations, the devices (7) are temporarily secured to the tubing (3). Then, the semic source (10a) located far from the maritime exploration platform (1) is excited to generate semic waves. Thus, the devices (7) receive the semic waves that propagate through the formations, with or without reflection, and transmit the collected data to the measurement control unit (1a) through the cable (4).

After releasing the devices (7) from the tubing (3), the ordered set of devices (7) is moved vertically to place it at a different depth, and then the devices (7) are again fixed to the tubing (3), followed by the steps of excitation of the semic source (10a) and collection of semic waves by the set of devices (7). In this way, the set of devices (7) is displaced in a vertical position along the perforation (2) while being fixed and released with respect to the tubing (3) to collect semic information at different depths. This is particularly advantageous on the devices of the prior art that used only a device of seismic exploitation, since the set of devices (7) can collect semic information originated from the same semic source (10a), providing greater reliability in the acquired data and a significant reduction in the time required to take measurements at different depths.

It should be noted that the semic source (10a) can be located at different horizontal distances from the maritime exploration platform (1), then indicates arrow A, and that if desired, the vertical path of the set of devices (7) can be carried out respectively for each horizontal distance A.

Figure 2 illustrates a geophosic exploration system of the terrestrial type in which a set of seismic downhole devices is used incorporating the present invention. As illustrated, in this case the perforation (2) extends into the earth from a ground surface (G) and the tubing (3) is placed in the perforation (2) to define its cylindrical wall.

An exploration vehicle (11), which carries a measurement control unit (not shown), is parked on the ground surface (G) near the mouth of the perforation (2).

A winch (12) is adjacent to the vehicle (11) and the winch (12) has a relatively large diameter drum (12a). Around the drum (12a) the cable (4) is wound to which a plurality of semic devices (7) are spaced apart. The winch drum (12a) is rotatably held in the winch (12) and, by rotating the drum (12a) counterclockwise, the cable (4) unwinds from the drum (12a) and descends in the perforation (2) by way of a three pulley guide assembly (13) that is suspended in its position by means of a chain (14). It should be noted that this three pulley guide assembly (13) can also be used in the maritime type system mentioned above.

The detailed structure of the three pulley guide assembly (13) is illustrated in Figures 3 and

Four. As illustrated, the guide assembly (13) includes a U-shaped inverted support (13a) to which a hook (13b) is attached. The support (13a) rotatably supports a pair of triangular plates (13c) between which three pulleys (13d) are rotatably provided. The operation of this guide assembly can be illustrated more fully by referring to Figures 5a-5c. Following is illustrated in Figure 5a, when the cable (4) of the guinche drum (12a) is unwound, the cable (4) advances in the direction indicated by the arrows due to the traction force applied to it by the weight (6 ), and in this way one of the seismic exploration devices (7) is mounted on the two pulleys (13d). Then, when the cable (4) continues to advance, the pair of triangular plates (13c) rotates clockwise as indicated by the arrow in Figure 5 while keeping the device (7) mounted on the two

000 730 adjacent pulleys (13d). Figure 5b illustrates the condition in which the pair of triangular plates (13c) have rotated through 60R Then, as the cable (4) advances further, the device (7) moves away from the pulleys (13d) and the Pair of triangular plates (13c) adopt the position illustrated in Figure 5c and remain stationary until the arrival of the next device (7). In this way, the pair of triangular plates (13c) rotates 120 ^ each time one of the devices (7) passes through the glutton assembly (13).

The structure of the downhole semic scanning device (7) used in the scanning system illustrated in Figures 1 and 2, will be described in detail below, referring to Figures 6 to 8. It should be noted that Figures 6 to 8 They are all of a schematic nature to assist in the understanding of important aspects of the semic scanning device (7) of the present invention. As illustrated in Figure 6, the downhole septic exploration device (7) has a two-part structure:

1) a carrier (19) including a pair of end blocks (22a and 22b) and a pair of side blocks (23a and 23b), and

2) a sensor package (25).

When armed, the carrier (19) defines an interior space within the end and side blocks (22a, 22b, 23a and 23b), in which the sensor package (25) is positioned by means of the rings (24a and 24b), which allow the sensor package (25) to be uncoupled from the carrier (19) although it is held in position by the carrier (19).

As illustrated in Figure 6, the carrier (19) includes a front end block (22a) having a central opening through which a cable (20a) extends. A knob (21a) is fixed to one end of the cable (20a) so that the latter is in connection with the front end block (22a). The cable (20a) contains a plurality of electrical conductors (30), some of which are connected to connecting pins (27) of the sensor package (25) while the other conductors (30) extend into a pair of passages of guide (28a) formed in the front end block (22a). The carrier (19) also includes a rear end block (22b) similar in structure to the front end block (22a). The rear end block (22b) links a cable (20) having a recess (21b) at one end and is provided with a pair of guide passages (28b). When assembled, the side blocks (23a and 23b) extend in parallel between the front and rear end blocks (22a and 22b). Each of the side blocks (23a and 23b) is elongated and is provided as a link between the front and rear blocks (22a and 22b). The side blocks (23a and 23b) are partially recessed to define intermediate guide passages (29a and 29b), respectively, to define a conduit formed by the guide passages (28a, 29a or 29b and 28b). Said conduit is particularly advantageous since, when the devices are arranged in series as illustrated in Figures 1 or 2 in the form of an ordered assembly, the devices can be connected in parallel with the host unit, such as the measurement control unit (1a), in which case the lack of a device (7) did not result in the failure of the device as a whole.

The sensor package (25) is generally cylindrical and elongated and is placed in the internal space defined by the carrier (19) to improve the signal-to-noise ratio by preventing tube and cable waves from reaching the sensor package. The sensor package (25) is supported by the carrier (19), but since this support is provided by the closed rings (24a and 24b), the package (25) is uncoupled from the carrier (19). For this purpose, the closed rings (24a and 24b) preferably comprise an elóastic material such as rubber.

The sensor package (25) has a front end shaped to define a seat to keep the closed ring (24a) in position as it is received therein and a similar rear end shaped to receive and retain the closed ring (24b) in position. . The closed rings (24a and 24b) are in abutment relationship with defined shoulders at the front ends of the end blocks (22a and 22b).

The sensor package (25) generally comprises four sections S1-S4 arranged along its longitudinal axis. The S1 section is a control section that contains several electronic elements to control the operation of the device (7) and the S2 section is a detector section that contains at least one seismic or geoophone detector. The S3 section is a fixing section to temporarily secure the sensor package (25) to the tubing (3), and the S4 section is a driving section to drive the S3 fixing section. In the preferred embodiment, the fixing section S3 includes a magnetic fastener using a permanent magnet. The fixing section S3 also includes a pair of fixing plates (26a and 26b) arranged approximately parallel to both sides of the sensor package (25) and forming part of two pole pieces to guide the path of the magnetic flux. It was noted that each of the fixing plates (26a and 26b) has an upper and lower lateral contact surface (31) brought into close contact with the inner peripheral surface of the tubing (3). The lateral contact surface (31) is adequately curved or inclined so that it can be brought into close contact with the inner peripheral surface of the tubing (3). Accordingly, when the device (7) is fixed to the tubing (3), only the sensor package (25) is effectively fixed to the tubing (3) with the contact surfaces (31) of the fixing plates (26a and 26b) contacted with the inner peripheral surface of the tubing (3), so that the sensor package (25) is effectively isolated from the carrier (19) as regards vibrations. It should be understood that the sensor package (25) can be fixed to the tubing (3) in one of two possible ways, that is in the upward or downward direction illustrated in Figures 7 and 8. If desired, an excentralizer can be provided to carry the device (7) more close to the tubing, as would be well known to those skilled in the art.

Figures 9a and 9b illustrate schematically

000 730 the internal structure of the magnetic fixing section S3. As illustrated, the sensor package (25) includes a cylindrical housing that houses several components in an isolated pressure and air condition. Inside and along the inner peripheral surface of the housing (35) a pair of upper and lower magnetic flux separators (32a and 32b) and a pair of left and right magnetic flux guide members (33a and 33b) are provided ). The spacers (32a and 32b) comprise a non-permeable material, while the guide members (33a and 33b) comprise a permeable material, thus defining part of the aforementioned pole pieces. When the spacers (32a, 32b) and the guide members (33a, 33b) are assembled, they define approximately a ring, as illustrated in Figures 9a and 9b. Inside this ring there is a permanent magnet (34) having a pair of poles N and S, generally cylindrical and rotatably supported. The magnet (34) preferably comprises rare earth cobalt. As described above, the pair of fixing plates (26a and 26b) also comprise a magnetically permeable material and also define part of the pole pieces.

The fixation and release operation of the magnetic fixer described above will now be described with reference to Figures 9a and 9b. As mentioned above, the permanent magnet (34) is rotatable with respect to the spacers (32a, 32b) and the guóa members (33a, 33b) that are fixed to the housing (35) and, when the magnet ( 34) is oriented such that its N and S poles are up and down as illustrated in Figure 9a, that is adjacent to the flow separators (32a and 32b), the magnetic fluxes are short-circuited between the N and S poles by way of the corresponding guóa member (33a, 33b) and the fixing plate (26a, 26b), as indicated by the dotted lines of Figure 9a. Here, this condition is designated as disconnected (“OFF”), indicating the absence of the fixed function. On the other hand, if the magnet (34) is rotated 90 ° from the condition illustrated in Figure 9a, the magnet (34) is oriented such that its poles N and S are to the left and right as shown by the Figure 9b, that is, adjacent to the flow guide members (33a and 33b). In this case, since the magnetic flux separator (32b, 32a), comprising a magnetically non-permeable material, is located between the guide members (33a and 33b), the magnetic flux emanating from the N pole tends to be directed towards outside the sensor package (25). Because the insurance plates (26a and 26b) comprise a magnetically permeable material, a magnetic circuit closed by the pair of insurance plates (26a and 26b) and the tubing (3) is defined, as indicated by the dotted line in the figure 9b. As a result, the insurance plates (26a and 26b) are fixed to the tubing (3) by magnetic attraction. This condition would be a connected condition (“ON”), since the device (7) heard the sensor package (25) was secured to the tubing (3). Preferably, any gap or gap between the contact surface (31) and the inner peripheral surface of the tubing (3) should be as small as possible, desirably zero, in order to obtain a more prominent fixing effect.

Therefore, it should be understood that the conditions of "ON" and disconnected ("OFF") are set alternately each time the cylindrical magnet (34) is rotated through 90^°Thus, all that is needed to establish the on / off condition (“ON / OFF”) is nothing more than the rotation of the cylindrical magnet (34). This novelty is advantageous because the torque requirements for the insured operation are substantially constant and significantly lower than in the case involving a movement of movement, such as a lever action. As was clear, an impeller for the magnet (34) can be a simple motor that can contribute to a compact size and light weight of the overall structure of the device (7).

A downhole seismic scanning device constructed in accordance with the present invention will now be described in detail, with reference to Figures 10 to 22. It should be understood that this specific embodiment comprises the basal structure illustrated schematically in Figures 6 to 8. Of this Thus, the device has a two-part structure that includes a carrier (39) and a sensor package (44). The carrier (39) was formed by a pair of upper and lower front end blocks (60 and 40), a pair of upper and lower rear end blocks (61 and 41) and a pair of side blocks (42 and 43) . It should be noted that the upper and lower front end blocks (60 and 40) are of similar construction with the exception of slight differences and that they are assembled on their contact surfaces to define a front end block assembly.

Figure 10 illustrates the downhole seismic scanning device, generally in plan view with the upper front and rear end blocks (60 and 61) removed and the sensor package (44) in section along the horizontal longitudinal plane. As illustrated, the inner front end block is relatively flat and elongated and was provided with a lower front groove (40a), of semicircular cut which, together with an upper front groove (60a) (also cut semi-circular). circular) in the upper front end block (60), defines a mouth through which a cable can be extended, topically a composite cable including a steel wire, a plurality of coated electrical conductors arranged around the wire and a protective coating that encloses the wire and the conductors. Preferably, a rubber jacket can be provided at the mouth to protect the cable. The block (40) was also provided with a locking cap (40b) to receive a fixedly secured recess to the wire according to which it forms the core of the cable, as explained below.

The block (40) also includes a pair of lowered guide passages (40c1 and 40c2) that extend forked from the groove (40a). These guide passages (40c1 and 40c2) are connected to intermediate guide passages (42c and 43c)

000 730 (figure 12) recessed in the side blocks (42 and 43), respectively. Also provided in block (40), in communication with the glutton passage (40c₁), there is a passage of glutton (40c3) In this way, the electrical conductors of the cable extend along the bifurcated guide passages (40c1 and 40c2) as divided, and some of the conductors that extend along the passage (40c1) extend along the input passage (40c3) to be connected to the connectors (47) of the sensor package (44). In the illustrated embodiment, the rear end of the block (40) is provided with an inclined shoulder (40d).

Figure 11 illustrates, when the upper and lower front end blocks (60 and 40) are assembled, a mouth (40a), passages (40c) and a shoulder inclined inward and circumferentially continuous (40d) are defined. Although there are some differences, the upper and lower rear end blocks (61 and 41) are built on the basis of the same principle. For example, the lower rear end block (41) is provided with a semi-circular groove (41a), a closing cap (41b), a pair of bifurcated guide passages (41c1 and 41c2) and an inclined shoulder ( 41d). However, it should be noted that each of the end blocks (40, 41, 60 and 61) is provided with a pair of link projections, that is 41e for block 41 and 61e for block 61, the following illustrates the Figure 11, each of which can be linked to the corresponding link notch provided in each of the side blocks, such as 42a and 42b for block 42 and 43a and 43b for block 43.

When the carrier (39) is assembled, an open internal space is defined on two sides and into which the sensor package (44) can be placed. The sensor package (44) is generally cylindrical in shape and includes four sections, as described with reference to Figure 6. Making a detailed description, the sensor package (44) includes a cylindrical housing (49) and a pair of front and rear end members (48 and 53) which are sealed sealed at the respective ends of the housing (49). The front end member (48) is provided with connectors (47) that extend outwardly from the sensor package (44) in the forward direction and that are connected to internal connection pins (47a).

The front end member (48) also has a circumferential spine (48a) that defines a seat for receiving and holding a closed elastic ring (45). The circumferential spine (48a) also serves as a retaining flange against which one end of the cylindrical housing (49) abuts. In addition, the front end member (48) is provided with a pair of circumferential grooves (48b) in which elastic closed rings can be placed to provide a tight seal.

Next to the front end member (48) and inside the cylindrical housing (49) a control section (50) is defined in which a pair of printed circuit boards (50b) are provided, fixedly secured to a plate of support (50) and each of them having several electrical and electronic components mounted therein, such as an IC chip (50a). The control section (50) is electrically connected to a host unit such as a data acquisition system, and the general operation of the present seismic scanning device, such as fixation / release and seismic data detection, is controlled by the control section (50). Next to the control section (50) there is provided a detector section (54) in which one or more semesic or geophone detectors can be arranged. Preferably, three seismic detectors of identical structure but oriented mutually orthogonally to each other are provided in the detector section (54). This three-dimensional arrangement of three identical seismic detectors is advantageous because it allows the acquisition of seismic data that propagates in any direction. Next to the detector section (54) a test section / motor switch (55) is provided that includes a piezo stirrer to test the insurance condition and a motor switch to automatically deactivate a driving source to change the fixing / release condition, follow I will clear up ahead. Next to the interrupter section of the test motor (55) a clamping section (56) is provided and, as will be clear later, said section (56) contains a magnetic coupler that incorporates a permanent magnet. Also, as illustrated in Figure 13 in cross-section, the clamping section (56) is also equipped with a pair of clamping plates (51 and 52) arranged in parallel along the longitudinal direction and spaced apart from each other. . The clamping plates (51 and 52) comprise a magnetically permeable material and are fixedly secured and define part of the cylindrical shell (49). It should be noted that said plates (51 and 52) have a transverse length that is greater than the outer diameter of the cylindrical shell (49) and that their lateral surfaces (51a and 52a) are beveled, curved or otherwise adequately machined in such a way that they can be brought into contact with the inner peripheral surface of the enclosure (3) when they are fixed on the imprisoned condition so as to achieve the greatest attractive force under given conditions. This is because the presence of some space between the lateral surface (51a and 52a) and the envelope (3) tends to lower the magnetic flux density and thus reduce the force of magnetic attraction.

As best illustrated in Figure 13, a pair of upper and lower magnetic flux separators (72a and 72b), comprising a magnetically permeable material, is provided in the clamping section (56). These separators (72a, 72b) and the lateral guides (71a and 71b) are arranged along the inner peripheral surface of the cylindrical shell (49), generally in the form of a support ring, being fixedly secured to said surface peripheral interior. Within the support ring defined by the spacers (72a, 72b) and the side guides (71a, 71b), a perma magnet is rotatably7

000 730 cylindrical with a pair of magnetic poles N and S and preferably comprising rare earth cobalt. Since the structure illustrated in Figure 13 is basically the same as that illustrated in Figures 9a and 9b, the operation of the clamping section (50) will be evident when referring to that portion of the present which concerns Figures 9a and 9b. It is clear that the condition illustrated in Figure 13 corresponds to the condition "OFF" (disconnected) when the magnetic flux is short-circuited and the condition free of imprisonment is established.

Next to the clamping section (56) a control section (57) is provided to rotate the permanent magnet (70) inside the clamping section (56). The control section (57) is baosically divided into two sub-sections: a direct current motor and a set of gears, then clarified further ahead. The control section (57) has a control axis (57a) that is operatively coupled to the permanent magnet (70). Then it became clear later on, when the direct current motor of the control section is energized, the permanent magnet (70) begins to rotate, and when the permanent magnet (70) has turned 90 °, this is automatically detected by the section motor switch (55) and the direct current motor is deactivated, thereby establishing the imprisonment / de-imprisonment condition.

It should also be noted that the rear end member (53) is also tightly assembled within the rear end of the cylindrical shell (49) and a seat to maintain an elliptical "O" ring (46), in position as it is received there. . This "O" elastic ring (46), is interposed between the circumferential edge (53a) that serves as a stop flange against the rear end of the cylindrical shell (49) and a seat to hold an "O" ring in position. The diagnosis (46) as received there. The "O" elastic ring (46) is interposed between the circumferential edge (53a) and the inclined shoulder (41d and 61d) (not shown) of the lower and upper rear end blocks (41 and 61). As mentioned before, the “O” rings (45 and 46) interposed between the carrier (39) and the sensor package (44) effectively function as a shock absorber to absorb vibrations, so that unwanted vibrations, such as be the originals of the tubular waves, be imparted to the sensor package. Additionally, it also prevents other unwanted vibrations, which can be transmitted through the well bottom cable, from being applied to the package (44) through the carrier (39). In this sense, the package (44) is acoustically decoupled from the carrier (39).

Figure 15 shows in perspective the overall structure of the current seismic scanning device at the bottom of the well, as it is armed and connected to a well bottom cable (64) at both ends. As described above, the seismic scanning device includes the carrier (39), in general in the form of a catamaraon and has an interior space (39a) open on its opposite sides, the sensor package (44) being located in the internal space (39a) by means of the elastic "O" rings (45 and 46) interposed between the carrier (39) and the sensor package (44). In this configuration, the sensor package (44), which must be imprisoned to take semic measurements, has a length of the order of 0.25 meters and a weight of the order of 4 kilograms. It should be understood that the carrier (39), basically, can have any desired length and weight, since the carrier (39) is effectively part of the cable (64) and is functionally isolated from the sensor package (44) as regards semic measurements

Some aspects of the internal structure of the sensor package (44) will now be described in detail with particular reference to inclusive figures 16 to 19. As illustrated in Figure 16, the cylindrical envelope (49), which basically defines an outer envelope of the sensor package (44), is provided with the pair of clamping plates (51 and 52) secured thereto. In other words, in manufacturing, the cylindrical wrapper (49) is partially clipped to receive inside it the pair of clamping plates (51 and 52), which are then secured to the wrapper (49), such as by welding. A pair of mounting holes (49a) located at the front end of the cylindrical housing (49) is provided on the front end member (48). Through these holes, screws can be inserted into the threaded holes (48c) provided in the front end member (48) so that the front end member (48) is fixedly secured to the casing (49).

Figure 17 shows the contents of the sensor package (44) and, as already described, includes the control section (50), the detector section (54), the test motor switch section (55), the control section. imprisonment (56) and the control section (57), listed from the front end to the rear end. The control section (50) has a support plate, one of whose ends is fixedly secured to the front end member (48), while the opposite end is fixedly secured to the detector section (54). Two printed circuit boards (50b), on opposite sides, are fixedly secured on the support plate, each of said printed circuit boards (50b) having various electrical and electronic elements (50a) mounted thereon. The front end member (48) has outer connector bolts (47b) enclosed by the connectors (47), and a pair of rubber "O" rings (65), fitted in the circumferential grooves (48b) formed in the member front end (48). As described above, the front end member (48) is also provided with a pair of threaded holes (48c), only one of which is shown in Figure 17, to allow a screw connection between the front end member ( 48) and the cylindrical shell (49).

The detector section (54) can take any form well known to a person versed in the art, to provide in it any desired semic detector.

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The detailed structure of the test engine interrupter section (55) is schematically illustrated in Figure 19. As illustrated, this section (55) includes four identical contour plates, mounted one above the other in the armed state. A switch plate (80) is formed with a pair of longiform grooves (80a and 80b) arranged perpendicularly with respect to each other in the form of a T provided with a pair of reed switches (81a and 81b) located at least partially in the respective slits (80a and 80b). A switch spacer plate (82), formed with a T-shaped groove (82a), corresponding to the T-shaped arrangement of the tongue switches (81a and 81b) is also provided.

A vibrating part plate formed with a rectangular slit (83a) and provided with a vibrating piezo (84) is also provided, which typically comprises a so-called bimorphic element. In the illustrated example, the piezovibrator (84) is rectangular in shape and has an end fixed to the plate (83) by means of a cantilever fixing element (84a). Thus, the vibrating piezo (84) can begin to vibrate when it is excited so as to apply vibration to the sensor package (44), thereby imposing a retention on the state of imprisonment between the sensor cabinet (44) and the envelope (3) . Finally, a vibrating spacer plate (85), formed with a rectangular slit (85a) to receive the vibrating piezo (84), at least partially, when armed is provided. The use of a vibrating piezo is advantageous compared to the conventional use of a geophonic vibrator, since the risk of an electromagnetic coupling between the vibrator and the detecting geophone is eliminated, thus avoiding the need to provide greater vibrating and vibrating spacing. allowing the sensor package to be more compact. Additionally, the piezo-vibrator is itself substantially smaller than a geophone, allowing an additional reduction in regard to the need for space.

Figure 18 shows in detail the link between the imprisonment section (56) and the control section (57). As described above, the clamping section (56) includes the pair of upper and bottom separators (72a and 72b) of magnetically non-permeable material and the pair of left and right side guides, generally arranged in the form of a ring. of support in which the cylindrical permanent magnet (70) with a pair of poles N and is rotatably received

S. The magnet (70) is provided at its center with a receiving hole (70a) of rectangular cross section as illustrated. On the other hand, the control section (57) includes a direct current motor (57 ') and a gear set (57 ") operatively coupled to the motor (57'). The gear set (57 ') has a drive shaft (57a) that projects externally and has a rectangular cross section corresponding to the receiving hole (70a) in order to be received there. In this way, the cylindrical magnet (70) is operatively coupled to the direct current motor (57 ') to be able to rotate by connection between the receiving hole (70a) and the drive shaft (57a).

Figure 20 illustrates, in schematic form, the relative positions of the clamping section (56) and the switch plate (80). As illustrated, the reed switch (81a) is arranged vertically and the other reed switch (81b) is arranged horizontally. The vertical tongue switch (81a) has a terminal connected to a first contact (86a) of a switch (86) and its other terminal connected to the direct current motor (57) and a terminal of the horizontal tongue switch (81b), which has its other terminal connected to a second contact (86b) of the switch (86) which, in turn, has a common contact (86c) connected to the direct current motor (57) through a power source (87 ). First, the operation of the tongue switch (81) with a pair of terminals (88a and 88b), referring to Figures 21a and 21b, will be described. As illustrated in Figure 21a, if the direction of the magnetic flux MF is perpendicular to the tongue switch (81), then the said tongue switch is in a disconnected state whereby the two terminals (88a and 88b) they are disconnected; on the other hand, if the direction of the magnetic flux MF is parallel to the tongue switch (81), then this is in a connection state whereby the two terminals (88a and 88b) are connected to each other.

In the condition illustrated in Figure 20, the rotating magnet (70) is oriented in such a way as to horizontally position its pair of poles N and S. Accordingly, the tongue switch (81a) is maintained in the disconnected state because the direction of the magnetic flux in this situation is perpendicular to the tongue switch (81a) and on the other hand, the tongue switch (81b) is maintained in the connected state because of the direction of the magnetic flux it is parallel to the reed switch (81b). Since the tab switch (81a) is disconnected, no power is supplied to the control (57) although the switch (86) has its common contact (86c) connected to the first contact (86a) as illustrated. If the switch (86) is operated in order to establish a connection between the common contact (86c) and the second contact (86b), then the current is supplied to the command (57) because the tongue switch (81b) It is in the connected state. As a result, the direct current motor (57 ') is driven to rotate the magnet (70) and, when said magnet is rotated (70), the direction of the magnetic flux produced by the magnet (70) is also rotated. Thus, when the magnet (70) has rotated by 90 °, the direction of the magnetic flux becomes perpendicular to the horizontal tab switch (81b), causing its disconnection so that the current supply to the DC motor (57 ' ) is automatically cut, thus stopping the rotation of the magnet (70). At the same time, the vertical tongue switch (81a) is connected since the direction of the magnetic flux in this condition is parallel to the vertical tongue switch (81a). In this way, having the arrangement of the pair of tongue switches (81a

000 730 and 81b) the shape of a "T", that is perpendicular to each other, the magnet (70) is actuated in order to rotate in 90^or each time the switch (86) is operated. It should be understood that the switch (86) is preferably an electronic switch mounted on one of the printed circuit boards (50b) in the control section (50).

Now, returning to Figures 22 and 25, the connection between the composite cable (64) and the carrier will be described in detail. Figure 22 is a schematic, exploded and fragmentary view showing the sensor package (44) located above the carrier (39) with the upper front end block (60) removed. As illustrated, the composite cable (64) includes a steel wire defining the core of the cable (64), a plurality of coated conductors (92) arranged around the steel wire (90) and a protective sheath (93). At one end of the steel wire (90) a stop (91) located inside the locking cavity (40b) is fixed, forming an integral part of the lower front end block (40). The cable (64) partially fits into the groove (40a) formed in the lower front end block (40). In this way, the carrier (39) is mechanically connected to the cable (64) by connection between the stop (91) and the locking cavity (40b). In addition, and as illustrated in Figure 25, the cable (64) is preferably protected against excessive flexion at the points where it joins the carrier (39), for example when the tool is hoisted to locate it within the perforation, protection that can be achieved through strong elóasticas covers (95). These covers enclose and extend along the cable (64) and have mounting rings (96) that fit over the ends of the carrier (39), being there secured by means of fixing screws (not shown). The covers (95) are strong enough to limit the curvature that can be applied to the cable adjacent to the carrier (39), even when said cable is strained in a right angle to said carrier (39).

The conductors (92) extend along the bifurcated guide passages on both sides of the lock quality (40b) and project into the duct passages (42c and 42c) formed in the side blocks 42 and 43 respectively. As illustrated in Figure 22 some (four in the illustrated example) of the conductors (92) pass through the input passage (40c) so as to be connected to the connectors (47) of the sensor package (44). It should be noted that the inwardly inclined shoulder (40d) has been illustrated as formed on the lower edge of the block (40) so as to receive the elliptical "O" ring (45). Conventional rubber covers (93) of rubber (93) are provided at the ends of those conductors passing through the entrance passage (40c3) in order to protect the connection between the conductors (92) and the connectors (47).

When the seismic scanning device at the bottom of the well has been constructed to present a two-part structure, including a carrier and a sensor package as described above, said sensor package or assembly may be of reduced size and light weight. way of obtaining semic data with a high degree of accuracy and reliability. Because of this, such a semic scanning device can be incorporated into the apparatus, in the form of an assembly such as the one described above. Alternatively, it can be used in combination with other types of geophysical scanning apparatus, such as the so-called sonic and density apparatus.

In figures 23 and 24 two such examples are schematically shown. The combined apparatus illustrated in Fig. 23 is for an explosive verification examination and includes a composite apparatus (100) comprising a sonic scanning apparatus (100a), a density scanning apparatus (100b) and a seismic assembly cartridge of well bottom (100c) plus a set of well bottom seismic exploration devices. The well bottom cartridge (100c) for the ordered set of devices (7) contains several electronic devices for signal acquisition and telemetry. It should be noted that a head nose can be placed on top of the sonic scanning apparatus (100a) and, similarly, a bottom nose can be placed at the bottom of the well-bottomed seismic assembly cartridge (100c), as is well known for People versed in art. In this configuration, you can carry out sonic, densimetric and time of arrival measurements, all at the same time. The time of semic arrival was used to correct the sonic records in real time. The two well-bottomed seismic exploration devices (7), spaced apart from one another at a distance fixed by the cable (4) can be used to measure delta T, which is the time required exactly by the semic wave to move from a scan device to the next scan device.

On the other hand, another combined apparatus illustrated in Figure 24 is for three-dimensional vertical seismic profiling (VSP), which is a technique of simultaneously recording upward and downward wave trains as is well known in the art. In a deviated well exploration or in a decentralized VSP, it is very useful to know in which direction the seismic signal comes. It is common to use a cardiogenic mount for geophones, but a cardiac mount tends to be of complicated and unreliable structure and, moreover, requires a large installation space that makes the apparatus large in size and high weight. As an alternative, a combination of a seismic well bottom assembly with a gyroscopic navigation apparatus, a tubing collar collar locator and a gamma ray apparatus can provide three-dimensional information regarding the orientation of the apparatus. The gyroscopic navigation apparatus, tubing collar locator and gamma ray apparatus are all well known in the art in which the gyroscopic navigation apparatus is for examining the configuration of the well and a combination of tubing collar locating apparatus and of Gamma rays are used to find the location of the device relatively to the underground formations. Based on this con10

000 730 of course, the combination of apparatus illustrated in Figure 24 includes the well-bottomed seismic assembly cartridge (101c), a set of seismic scanning devices (7) and a composite apparatus (102), comprising the gyroscopic navigation apparatus (102a), the tubing collar apparatus (102b) and the gamma ray apparatus (102a). The composite apparatus (102) is provided at the bottom end of the cable (4) so ​​that it also serves as a weight to assist in the downward movement of the entire combined apparatus along the perforation. With this structure, the tubing collar locator and the gamma ray apparatus correlate the depth scale relatively to the tubing collars and the formation. Since the configuration of the well can be obtained from the registers of the gyroscopic navigation apparatus with data related to the inclination of the devices of semic exploration (7), the three-dimensional movement of the propagation of the semic wave can be decomposed into Cartesian coordinates, a vertical and two horizontal, for all levels of the device.

As described in detail above, in accordance with the present invention, a well-bottomed seismic exploration device is provided, capable of executing, with high accuracy, the geophosic exploitation. In view of the fact that the present device can be of reduced size and light weight, it can be incorporated into an assembly provided with a plurality of devices. In this case, the cosmic measurements can be carried out at multiple depths, while using the same semic source, which significantly contributes to reducing the time required to obtain measurements and accentuated the reliability and accuracy of the measurements. In addition, when a magnetic clamp is used to temporarily clamp the device against the perforation tubing, the overall structure of the semic scanning device may be more compact in its size. In addition, in cases where the seismic scanning device has been devised to present a structure consisting of two parts, carrier and sensor package assembly, the ism can be structured in such a way that only the sensor package is imprisoned to the tubing of the perforation, thus increasing the accuracy of the semic measurement. In the preferred executive mode, the magnetic clamp is provided in the sensor package. In the structure consisting of two parts, with the provision of a shock absorber between the carrier and the sensor package, the latter can be acoustically decoupled from the carrier and the bottom of the well, so that any undesirable vibration can be prevented from being transmitted to the sensor package that contains several detectors, such as being semic detectors, thus allowing measurements to be made at a high S / N ratio. In addition, with the provision of the passage of conduit in the carrier, when it is included in such a set, each of the seismic exploration devices in the assembly can be electrically connected in parallel to the host unit and thereby a local fault not It resulted in a total failure.

A device and an apparatus according to the present invention, intended for semic exploration at the bottom of the well, have been described and illustrated herein. While particular executive embodiments of the invention have been described, it is not the invention that it is limited thereto. Therefore, for those skilled in the art, it will be apparent that various changes and modifications can be made to the described invention without departing from the spirit and scope of the appended claims.

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