Abstract:
A drilling machine for a drilling rig and a drilling rig which can be used for exploratory drillings and producing wells, particularly in hydrocarbon deposits, both onshore and offshore. The drilling machine includes a base, on or in which a top drive is displaceable axially to the longitudinal axis of the base and a pipe-handling apparatus which is movable, especially by sliding, perpendicularly to the longitudinal axis of the base and which grips the drilling pipe. The base is pivotably and/or rotatably mounted in the region of the foot, and it is possible for a virtually continuous drilling process to be carried out using a combination of two drilling machines.

Description:
This is a U.S. national stage of application No. PCT/DE99/02598, filed on Aug. 19, 1999. Priority is claimed on that application and on the following application: 
     Country: Germany, Application No.: 198 37 692.8, Filed: Aug. 19, 1998. 
    
    
     SUMMARY OF THE INVENTION 
     The invention relates to a drilling machine for a drilling rig and to a drilling rig which can be used for exploratory drillings and producing wells, particularly in hydrocarbon deposits, both onshore and offshore, and to a method for sinking such a well. 
     Modern drilling rigs according to the prior art consist of a large number of components, such as a drawworks, an iron roughneck, a working stage, a pipe-handling apparatus, a pipe rack, a crown block with a traveling block and a top drive, a pipe ramp and a catwalk for the drilling pipe, together with various auxiliary devices for handling. 
     Such drilling rigs have the disadvantage that they consist of a large number of components which, because of the constant changing of the drilling location of the drilling rigs, entail elaborate and costly logistics and large numbers of personnel. 
     European published patent application 0 243 210 A2 describes, for example, a conventional drilling machine of modular construction. It contains all components necessary for drilling machines, such as a collapsible drilling tower, which rests on a displaceable substructure by means of four legs. In its upper part it has a crown block and a top drive, together with a traveling block, and in its lower part it has a breaking and securing apparatus. Part of the drilling mast is directed by means of lifting cylinders. The absolutely necessary drawworks is arranged on the displaceable substructure and, via cables and via the crown block, forms a connection to the top drive. In addition, a pivotable pipe handling boom is provided which guides the pipe into the drilling machine. 
     However, this drilling machine still has a large number of components which, although of modular design, nevertheless have to be assembled and dismantled and transported from drilling location to drilling location. This requires a substantial effort in terms of personnel and logistics. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a drilling machine and a drilling rig, and also a method entailing substantial savings with regard to the equipment of the drilling rig and with regard to logistics and personnel costs. 
     The drilling machine according to the invention consists of a base, on or in which a top drive displaceable axially to the longitudinal axis of the base and a pipe-handling apparatus which is movable, especially by sliding, perpendicularly to the longitudinal axis of the base and which grips the drilling pipe, are arranged, the base being pivotably and/or rotatably mounted in the region of the foot. 
     The bearing of the foot of the base may be mounted on or below the working stage of a drilling rig in the region of the drilling cellar or on a vehicle, such as, for example, a mobile workover rig. The ground, in other words the surface of the terrain, may also be used as a working stage. With a drilling machine of this type, the main drive and handling components are advantageously integrated in one system. This also eliminates the crown bearing, traveling block and drawworks that are customary in drilling rigs according to the prior art. Similarly, the pipe ramp and the catwalk are omitted. In addition, this integrated construction allows rapid transport from one drilling location to another (rig move time) and a reduction in the numbers of drilling personnel required. It is even possible to raise and set down the drilling machine according to the invention using a dirigible with a maximum lifting power of 160 tons, as this drilling machine is much lighter than a comparable drilling machine according to the prior art. Preferably, the base is formed in a type of rocker, for example in the form of a box structure. 
     A further embodiment envisages that a power roughneck is arranged below the pipe-handling apparatus and comprises a holder and a breaking and securing apparatus, the holder customarily being arranged below the breaking and securing apparatus. It is particularly advantageous to arrange only the breaking and securing apparatus in or on the base and to provide the holder, for example, on or under the working stage in order thus to reduce the weight of the base. The roughneck may also be arranged on the working stage. 
     In a further embodiment, the drilling machine may be designed to be horizontally slidable. This has the advantage that a drilling machine, especially an erect drilling machine, can be moved out of the region of the well and, in addition, adjusted relative to any pipe stores or to the center line. In addition, pipes can advantageously be removed from a plurality of pipe stores arranged side by side. 
     A locking apparatus is arranged at the upper end of the base and is connected to a steel structure, preferably a tower or a mast. This has the advantage that an additional rigidity for connection or bending purposes is achieved, and the steel structure can be much more simply and flexibly constructed than customary towers or masts. A further embodiment envisages that the locking device consists of a hollow cylinder to which a flushing hose is connected and on which a valve is arranged to ensure the flushing feed. Specifically when the base is pivoted, it is advantageous to integrate the flushing feed into the locking device, so that flushing is available virtually automatically without a further working step. 
     A drum may be arranged on or in the base, onto which the flushing hose can be rolled up, so that the risk of fracture or other damage during the laying and removal of pipes is avoided. 
     An elevator is provided for raising the base from the horizontal to the vertical, which, in a particularly advantageous embodiment, consists of one or more hydraulic or pneumatic cylinders or, in another alternative embodiment, is designed as a winch. As a result, drilling at an angle of from 5° to 90° to the surface of the terrain is advantageously enabled. 
     The top drive of the base can be designed to be displaceable by means of a linear drive, the linear drive being arranged in or on the base. Examples of linear drives that may be used include a spindle drive, a hydraulic drive and a chain or cable hoist. Guidance can be ensured, for example, by a sliding rail, racks or guide rollers. The linear apparatus consists of drive and guide means. 
     This has the advantage that workover, drilling and snubbing operations (e.g. pipe laying) can be carried out. 
     In a further embodiment, a pipe rack is arranged within the range of the pipe-handling apparatus, the individual pipes being arranged standing in the pipe rack. This has the advantage that the base can engage independently on the pipes, without additional apparatus, and then lower them into the well by means of the top drive. 
     The pipe-handling apparatus as a whole or the grippers or the gripper seating are arranged to be displaceable axially to the longitudinal axis of the base, which advantageously makes it possible to handle the pipes more efficiently as, for example, when setting down the pipe or removing it from the pipe rack. A further advantage lies in the fact that, by means of such a pipe-handling apparatus, the plug and socket thread of the pipe connector can be pushed together within a permitted travel. 
     A further advantageous embodiment envisages that the steel structure has a working stage, the fulcrum and/or pivot point of the base being arranged above or below the working stage. 
     As a result of the many possible variations of the drilling machine, it becomes possible to adapt the drilling machine to local conditions at the drilling location. 
     A further advantageous embodiment envisages that a damping device is arranged on the base and/or the steel structure, which prevents damage being caused by uncontrolled impact when erecting the base or when locking. Thus, advantageously, damping of the load when erecting or laying down the base can be achieved. 
     A line for flushing is provided on or in the base, the lower connector of the line being connected to the flushing pump and the upper connector being connected via the hollow cylinder to the flushing hose. This advantageously permits the integration of an additional unit, specifically the flushing supply for the well, into the base. 
     In one particular embodiment, the roughneck is pivotably connected to the base by means of a hinge, which is arranged on one side of the roughneck, or, in a different embodiment, is connected to the base in such a manner that it is displaceable perpendicularly to the axis of the base. A further possibility is for the roughneck to be raised via a coupling by means of the top drive. The advantage of such an embodiment lies in the fact that the down hole equipment can be installed in the well even with the base standing vertical. The hinge may be designed, for example, as a welded hinge. The roughneck may also be mounted on the working stage in a conventional manner. 
     In a further embodiment of the drilling machine part of the steel structure, preferably one or more corner pillars of the steel structure, is designed as a pipe rack or as a seating for a pipe holder. This saves weight, and simplifies the device as a whole, as fewer components are needed which, overall, permits both a cost saving and the establishment of a modular system. In this embodiment, the pipe rack or seating for a pipe holder can also be mounted to rotate about its longitudinal axis. The advantageous result of this is that the loading of the magazine can take place irrespective of continuing drilling operation, and that one pipe is always located within the gripping range of the pipe-handling apparatus for removal. Also particularly advantageous is an embodiment which envisages that the drilling machine and/or the pipe rack is mounted on a vehicle or a trailer, thus significantly increasing the portability and also the flexibility of use. 
     The invention also covers a drilling rig having two or more drilling machines are arranged and are alternatingly moved or rotated or pivoted over the center of the well. The advantageous effect of this is that drilling times can be substantially reduced, because one drilling machine can be loaded while another drilling machine is still sinking the well. Since the loading drilling machine is not located above the well during the loading operation, the second drilling machine is able to connect the previously loaded pipe with the pipe string in the well and continue sinking the well. A further advantageous effect of this is the creation of a drilling rig which can be used for virtually continuous drilling. Also, only a minimum of drilling personnel are required, since the drilling rig according to the invention can be run almost fully automatically, particularly in the handling of the pipes, casings, etc. Drilling machines which are rotatably mounted need not be connected and can be separately driven. 
     A particular embodiment of such a drilling rig envisages that two drilling machines are arranged substantially symmetrically, especially with axial symmetry, to the center line, the drilling machines being connected to one another. This connection is preferably performed by a substantially kinematic chain, a claw shaft, a cable or a chain. As a result, advantageously, it is possible to reduce the energy output for setting down a pivotable drilling machine while simultaneously erecting another drilling machine, both axes of the drilling machines extending in parallel. Drilling machines which are rotatably mounted need not be connected and can be separately driven. 
     These advantages can also be achieved if a steel structure is arranged between two drilling machines, to which steel structure the drilling machines can be reciprocally locked, the drilling machines being connected by means of cable or chain via a return point or a return roller which is arranged in the steel structure. 
     An embodiment wherein a damping device is arranged on the support devices of the drilling machines or the steel structure, the damping unit for example consisting of a hydraulic cylinder and a choke, has the advantage that the load can be damped when erecting or setting down a base of the drilling machines. 
     The method according to the invention for sinking a well and for installing drilling pipes is a method wherein a pipe is rolled onto a base of a drilling machine, the top drive being in an upper position, and the grippers of the pipe-handling apparatus are moved into the base, and then the pipe-handling apparatus grips the pipe as soon as the latter is lying in the intended position on the base. Subsequently, the base is raised by means of an elevator from a horizontal position into a position between 5° and 90°, and in a preferred embodiment the base is locked in a steel structure, or in a mast or tower, after the vertical or nearly vertical position has been reached. During the raising of the base or after locking of the base, the top drive is screwed to the pipe by the drive shaft of the top drive and is secured and is then moved with the pipe-handling apparatus or by means of the linear drive into the upper region of the iron roughneck, the lower breaking and securing apparatus of the iron roughneck grasping the lower pipe connector of the pipe and the holder holding the string. The pipe is then screwed by means of the top drive or iron roughneck to the drilling string within the well. The pipe-handling apparatus is again moved into the base and the holder for the lower pipe, connected to the drill bit, is opened and the drilling operation is begun, the top drive being lowered in the guide means of the base. By means of such a method, drilling with an integrated drilling device can be carried out flexibly and quickly with a small drilling crew. 
     A further stage of the method envisages that the base is displaced horizontally between picking up the pipe and preparing it for drilling and screwing to the lower pipe, which has the advantage that a further drilling device can meanwhile continue sinking the well. A further embodiment of the method according to the invention envisages that the pipe is removed from a pipe rack, in which the drilling pipe is arranged vertically, by means of a pipe-handling apparatus, which is integrated into a drilling device as claimed in claim  1 , and the pipe is then screwed to the top drive by means of the pipe connector and brought into the drilling position. The advantage of such a method lies in the fact, that, with the integrated drilling machine, the sinking of the well can take place with economy of space and energy. In a further embodiment of the method, the pipe rack, after removal of a pipe by the pipe-handling apparatus, is rotated sufficiently far about its own longitudinal axis for it to be possible for the next pipe in the pipe rack to be gripped by the pipe-handling apparatus. Thus the next pipe is automatically available for the next drilling section. 
     The method can advantageously also be embodied in that the drilling machine, after completion of a drilling section and release of the top drive from the drilling string in the well, is rotated about its longitudinal axis and then, after the top drive has been raised, removes a new pipe from the pipe rack by means of the pipe-handling apparatus. Thus the center line becomes free and, while the pipe-handling apparatus of the drilling machine is loading a new pipe, a second drilling machine can continue sinking the well. A further stage of the method envisages that two or more drilling machines are brought into position around a well, one drilling pipe being sunk in alternation while one or more of the other drilling machines are prepared for drilling by receiving a further pipe. As a result of this alternating interplay of two or more drilling machines, a high level of drilling progress per unit time can be achieved and cooling down times can be reduced, 
     A further embodiment of the method according to the invention envisages that, for the installation of drilling pipes, a pipe is removed from a pipe rack while the pipe rack is simultaneously being charged with further pipes, which has the advantage that the cooling down times can be even more greatly minimized, because the charging of the pipe rack can take place independently of the sinking of the well. This also reduces the drilling down times. 
     The method according to the invention can of course be employed, by reversing the sequence of method stages, to remove pipes, in which case hoists may also be employed which are arranged below the top drive and independently enclose the pipe (the tool joint). Tractive force is not exerted via the threaded connection as a result. 
     Instead of pipes, casings, sections, tubing, etc. may be used. The pipe rack may be designed as a pipe bin or finger stage. A pipe frequently consists of a plurality of individual drill rods (double or triple stands), which are screwed together even before being placed in the pipe rack. However, a pipe may also consist of only one drill rod (single stand). 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows the front view of a base with the individual components. 
     FIG. 1 a  is a view as in FIG. 1 showing one embodiment of a linear drive. 
     FIG. 2 shows the base in a lateral view. 
     FIG. 2 a  is a view as in FIG. 2 of another embodiment of the linear drive. 
     FIG. 2 b  is a view as in FIG. 2 of the embodiment in FIG. 1 b.    
     FIG. 2 c  is a view as in FIG. 2 of a further embodiment of the linear drive. 
     FIG. 3 contains a plan view of a guide means of a top drive. 
     FIG. 3 a  is a view as in FIG. 3 of the embodiment in FIG. 2 a.    
     FIGS. 4 and 6 show, respectively, the lateral and plan views of a pipe-handling apparatus. 
     FIG. 5 shows the lateral view of a gripper unit along the line A A′ of the pipe-handling apparatus in FIG.  4 . 
     FIG. 7 shows the plan view of a roughneck. 
     FIG. 8 shows a section through a locking apparatus with integrated flushing feed:, and 
     FIG. 9 shows the plan view of a drilling rig providing two opposite drilling machines. 
     FIG. 10 shows a lateral view of a drilling rig according to the invention with two drilling machines; 
     FIG. 11 shows a further example of embodiment of a guide means of the top drive in the base  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a base  1  designed as a “rocker” into which a top drive  2 , a pipe-handling apparatus  30  and an iron roughneck  4  are integrated, the latter comprising a breaking and securing apparatus  11  and a holder  12 , an optional possibility being to arrange the holder outside, for example below, the rocker  1  on a working platform, for example in order to save weight. In this example of embodiment, the rocker  1  can be transferred from the horizontal to the vertical position by means of a swivel apparatus  5  and is additionally mounted to rotate via a live ring  6 , which can for example consist of a toothed wheel, about the longitudinal axis in a vertical position of the rocker. Such a supporting apparatus may, of course, also be designed only with a swivel apparatus  5  or a live ring  6 . The connecting element  13  is connected at its upper end to the base  1  via a swivel bearing with a bolt  8 , and is seated at the bottom on the live ring  6 . In this arrangement, the upper part of the connecting element  13  is designed as an eye in which the bolt  8  of the swivel bearing is mounted. Above the movement apparatus  3 , the receiving plate  18  for the elevator (not shown) is connected to the live ring  6  or to the connecting element  13 , so that the receiving plate  18  is also moved during a rotational movement of the drilling machine. 
     The top drive  2  is provided, in this example of embodiment, with two motors  28  which introduce the torque into the drilling pipe via the top drive  2 . The top drive  2  is moved parallel to the longitudinal axis  20  of the rocker  1  from top to bottom or from bottom to top, preferably by means of a linear drive which is integrated into the rocker  1 . 
     FIGS. 2 a  and  3   a  show a linear drive or linear apparatus which is a chain drive system. The top drive system which is connected to the swivel apparatus  5  is moved in the vertical direction in this embodiment. The swivel apparatus  5  is equipped with a shaft  105 /sprocket  106  combination. The lower part of the base is equipped with a similar device. A chain is installed between both sprockets  106 . The support  104  is fixed with the base  1 . The top drive system  26 ,  27 ,  28  is connected via the receiving plate  25  and the support  109  to the chain. The lower sprocket/shaft combination is driven electrically or hydraulically with the motor equipped with a gear box unit. The embodiment shown in FIGS. 1 b  and  2   b  is a hydraulic linear drive. The receiving plate  25  is connected with a device  110  and the base  1  is additionally equipped with the device  111 . The receiving plate  25  is lowered or raised with two hydraulic cylinders  112  on the right and left side of the base  1 . The hydraulic cylinders are powered by a hydraulic power unit which is not illustrated in the drawing. The hydraulic cylinder is preferably a telescopic type which increases the performance of the overall drilling device in general. FIG. 2 c  shows an essentially conventional system for linear drive wherein the receiving plate  25  is lowered or raised with a winch  113  in conjunction with a drilling line  114 . The top of the base  1  is equipped with a sheave  115  and a deadline anchor  118 . The plate  25  is equipped with a traveling block  117 . The base  1  is equipped with a crown block  116 . Depending on requirements,  6 ,  8 ,  10  or more lines are used to handle the required loads. Other mechanical solutions could be taken into consideration as well. Vertically installed spindle which are provided in the upper and lower position could be used as well. The spindle rotates via an electric, pneumatic or hydraulic motor. The rotor bearing of the spindle is connected to the plate  25  for the lowering and raising of the top drive system. 
     Fixedly connected to the upper end of the rocker  1  is an entry lid  70  for a locking apparatus  60  by means of which the rocker can be engaged and locked into a securing apparatus (not shown) of a steel structure. Optionally, a flashing feed apparatus may also be integrated into this locking apparatus. If the drilling machine is used without the steel structure, as for example in the case of shallow wells, the locking apparatus  60  and the entry lid  70  are dispensed with. 
     The drilling machine is seated on a movement apparatus  3 , which can be displaced by means of rollers  15  on guide means or rails.  16 . 
     In this example, the top drive  2  is guided externally on the rocker by means of a receiving plate  25 , on which the top drive housing with the top drive  2  is fixed. The drive shaft of the top drive is designated  27 . As an alternative (not shown) the guide means for the top drive may also be arranged within the base. 
     FIG. 2 shows the lateral view of a rocker  1 , of rectangular design in this case, in which the top drive  2  is mounted externally on the rocker by means of a receiving plate  25 , to which rocker the top drive housing  26  with the top drive  2  is fixed. A base or rocker which is rounded at the corners may of course also be used. In the region of the pipe-handling apparatus  30  are the grippers  37  whereby the pipe is gripped. The grippers are connected to one another by means of a gripper seating  36 . The gripper seating  36  may be displaceably arranged. The iron roughneck  4  is integrated in the lower region of the rocker  1 . In a further embodiment of the rocker  1  (not shown) no iron roughneck is integrated; in this alternative embodiment, the latter is on the working stage. A swivel apparatus  5  is shown at the foot of the rocker  1  and is seated on a rotating apparatus, designed in this example as a live ring  6 , which is driven by the motor  10 . The rotating apparatus is mounted in a swivel bearing  19 , in this case a roller bearing (ball/roller bearings and ball bearings are also possible). The live ring  6  is seated in a movement apparatus  3 , which is designed as a linear guide means and by means of which the whole rocker  1  can be displaced forward or backward (to the right or left in FIG.  2 ), in other words over or away from the well. Depending on application requirements, the base  1  can also be operated only with a rotating apparatus or a movement apparatus or a swivel apparatus or a combination of two of these apparatuses. 
     The receiving plate  18  for the elevator  7 , which in this case is designed as a telescopic cylinder, serves to retain it. The elevator  7  is articulated on the base at the top (true angle not shown). The pipe-handling apparatus  30  has been shown in simplified form in this example. Thus, an upward and downward movement cannot be performed. 
     Guide rails  22  are provided which serve to receive the top drive receiving plate  25 . This receiving plate  25  consists, in this example, of a bent structure formed from a U-shaped folding section in which the roller axles  24  for the guide rollers  23  are laterally mounted. Also mounted on the receiving plate  25  are the top drive housing  26  with the drive shaft  27  of the top drive. This shaft is above the center of the well  9  during drilling. 
     The guide rollers  23  are mounted by means of roller bearings and serve to guide the receiving plate  25  in the linear axis. 
     With the aid of a linear drive (not shown), a linear movement of the receiving plate can be made possible by means of the arrangement referred to above. The linear drive may be provided either by chains or by cables. A further possibility would be an elevator for the receiving plate  25  with the top drive housing  26  by means of a hydraulic cylinder, which also moves the receiving plate  25  axially relative to the longitudinal axis of the base  1 . FIGS. 4,  5  and  6  show an example of embodiment of a pipe-handling unit. The pipe-handling apparatus  30  consists of tongs  34 , in order to enable lifting out of the base  1 , a linear guide means  39  on the upper skid  45  and two gripping units, consisting in each case of the gripper seating  36 , the gripper  37  itself, a gripper arm  38 , an expansion cone  41 , a receiving plate  46  and rollers for the gripping arm  48 . 
     In this example of embodiment, the lifting movement is enabled by a tongs system. The tongs  34  are fixed on one side by fixed bearings  51 . Rollers  40  are secured on the other side of the tongs  34  and lie in guide means of the base skid  35  or upper skid  45 . The tongs  34  can be moved together or apart by means of a hydraulic cylinder  33 , which is installed in the lower tongs region between the axes, specifically on one loose and one fixed side of the tongs  34 . In order to facilitate the lifting movement from bottom dead center, this movement is supported by compression springs  50 . The kinematics of the lifting device can also be designed so that lifting out from dead center is avoided. This can be achieved, for example, in that the end position selected is not the closed position of the tongs  34  substantially parallel to the cylinder but a residual angle of, for example 15° remains. 
     In order to facilitate the setting-down of the pipe  78 , the gripper seating  36  is arranged to be linearly mobile on the upper skid  45 . This gripper seating  36  can be moved parallel to the axis of the base  1  via a pneumatic or hydraulic cylinder  32 , which is secured on the upper skid by means of a mounting  42 . In addition, the linear guide means  39  provides the possibility of introducing the pipe into the screwing and breaking apparatus of the iron roughneck  4 . 
     Secured on the gripper seating  36  in FIGS. 4 and 5, at the respective ends, are an expansion cone  41 , a cylinder  31 , a receiving plate  46  for the gripping arms  38  and restoring springs  49 , grippers  37  and rollers  48  for the gripper arms  38 . 
     By initiating the movement of the cylinder  31 , on the piston rod of which the expansion cone  41  is secured, the lower regions of the gripper arms  38  are pressed apart via the rollers  48  and the upper regions of the gripper arms  38  are moved together accordingly. The grippers  37  can generate sufficient force, via the lifting ratio of the gripper arm  38 , to hold the pipe (not shown). The plate mountings  42  and  43  serve to receive the cylinders  32 . In order to counter twisting of the tongs  34 , reinforcing ribs  47 , designed as junction plates, are provided. Other pipe-handling apparatuses can, of course, also be used. 
     FIG. 7 shows the plan view of a roughneck  4 . This roughneck  4  is secured on a baseplate  87  and can be pivoted by means of a hinge  81 . 
     The roughneck is secured on hinges  81 , which are connected to the base  1 , in order to permit the installation of down hole equipment. The roughneck is secured by a locking latch  89  with a lock in order to prevent pivoting away during drilling. The spacer  82  is located between the baseplate of the iron roughneck and the base  1  and simultaneously serves as a damping unit in the latched-in state. 
     In particular, in the embodiment of a drilling machine according to the invention which is only rotatable, the roughneck  4  need not be integrated into the base but can, for example, be arranged on the working platform. 
     FIG. 8 shows, in a special example of embodiment, in the case of a base  1  which is combined with a steel structure, a locking apparatus with integrated flushing feed during the locking operation. This locking apparatus  60  consists of a base body  62 , an internal hollow cylinder  67 , a lid  65  and the seals  64 ,  66 ,  68 . The volume flow of the flushing is passed through the upper aperture  71  on the base body (stator)  62 . If the pressure P 1  exists in the control pressure chamber  72  and the hollow cylinder  67  is in a lower locking position, flushing can penetrate through the holes  69  into the interior space of the hollow cylinder  67  and be passed to the flushing hose, which is integrated in the base  1 , through the aperture  75 . The hollow cylinder is sealed by the seals  68 ,  66  and  64 . The flushing hose, which leads to the flushing pump, is connected (not shown) to the aperture  71 . 
     The stator  62  is divided into two regions and appropriate sealing of the regions is provided by the seal  64 . The first region is the flushing pressure region (A) in the flushing space  63 , and the second region consists of the control pressure chambers  72  and  73  (B 1 , B 2 ). By controlling the pressure chamber (B 1 )  72  with P 1 , the flushing is passed via the aperture  71  and simultaneously the base  1  is locked by introducing the hollow cylinder  67  into the entry lid  70 . The entry lid  70  represents the topmost part of the base  1 . The seal between locking device  60  and the entry lid  70  is provided by means of a seal  74 . On the inside of the lid  70 , the flushing connector hose  59  is connected by means of a connector  57  to a connecting or coupling piece  58 . The connecting or coupling piece  58  is fixed on the lid  70 . The flushing connector hose S 9  leads to the flushing head. 
     By controlling the pressure chamber (B 2 )  73  with P 2 , the base  1  is unlocked by moving the hollow cylinder  67  out of the entry lid  70  of the base  1  and flushing is interrupted, as the upper cam  75  of the hollow cylinder  67  can be introduced into the upper region of the stator  62  and flushing can be cut off by a seal  61  in the stator. 
     FIG. 9 provides a sketched plan view of a drilling rig with two drilling machines. The use of two rockers or drilling machines has the advantage that, while one drilling machine is drilling, the other drilling machine can be charged with a new pipe  78  from the pipe rack  79  or prepared to be screwed to the pipes located in the well  103 . The way in which a pipe  78  is gripped from the pipe rack  79  is that the rocker is rotated in the vertical position by approximately 90° via the rotational apparatus  6  and then grips a pipe  78  by means of the pipe-handling apparatus, which is arranged in the pipe-handling region  30  within the rocker  1 , and is then rotated back again into the original position. By means of a movement apparatus  3 , the whole rig can be moved in a linear guide means sufficiently far toward the well  103  for the pipe to be located above the center line  9 . The movement apparatus is characterized by lateral rollers  15  which are guided on two rails  16 . The corner pillars of a steel structure (not shown), into which the base  1  is locked by means of the lid  70 , are designated  90 . The movement apparatus  3  is, for example, dispensable if the base  1  is charged with the pipe in the horizontal position. Via the locking apparatus  6 , which is shown in FIG. 8, the flushing is guided via the entry lid  70  into the pipe or well. After the drilling operation, the rocker is moved out of the well region by means of the movement apparatus  3 , after the locking apparatus  60  has been released from the locking (not shown) of a steel structure. A skid, for example, can also be used as a movement apparatus. 
     The pipe racks  79  receive the pipe  78 . They can be so designed that pipes of different lengths or different diameters can be placed in one seating. In this example of embodiment, three pipe racks  79 , also described as seatings, are set upright on both sides of each drilling machine. A special embodiment of each unit comprising three pipe racks  79  is shown on the left-hand side. In this case, the pipe racks  79  are arranged standing on a sliding system comprising rails  95 ,  96 . In this example, the transverse rails  96  are located below the longitudinal rails  95 , which are arranged substantially parallel to the movement apparatus  3 . 
     The seating  79  for the pipes can be displaced in two directions by means of this sliding system or can be interchanged with one another. The system is equipped with rails  95 ,  96  in both the longitudinal and transverse directions. The seatings have flanged rollers on their undersides, via which the linear movements can be reliably implemented. The changeover from the longitudinal to the transverse track can take place, in particular, via turntables  97  or a rotating disk or lifting devices (not shown). In the turntable embodiment, the seating stands on a rail system which is installed on a rotating apparatus. The seating is turned by means of a turntable to move it from the longitudinal to the transverse direction. The seating can now roll into a rearward position. In order to return to the longitudinal direction, it is again turned by means of a turntable. 
     A further embodiment is a lifting device below the transverse conveying rails  96 . The seating is displaced longitudinally. In the changeover position from longitudinal to transverse, the transverse rail is raised. The longitudinal rollers lift off the rail  95 , and the transverse rollers settle on the transverse rail  96 . Now the seating can be rolled onto the rearward track comprising two longitudinal rails  95 . 
     The seating  79  has longitudinal and transverse rollers (not shown), which are vertically offset in order to be able to be independent of one another in the rail system. 
     FIG. 10 shows a lateral view of an example of embodiment of a drilling rig according to the invention in the sinking of a well with a steel structure. 
     The steel structure consists of corner pillars  90 , only the rear pair being shown here, and a connecting or covering plate  98 , which connects the corner pillars  90  to one another and gives stability to the steel structure. In addition, the locking apparatus  60  is fixed thereto and can be used to lock a drilling machine to the entry lid  70  of the base. The necessary flushing hoses are not shown. The connecting plate  98  can also consist of steel girders fixedly connected to one another. The corner pillars  90  can also be constructed from steel sections connected to one another. Also, the steel structure can be assembled from two, three or more corner pillars  90 . 
     A working platform or stage  100  can, as in this example of embodiment, be arranged on the steel structure between the corner pillars, and is located approximately at the height of the live ring  6  or the swivel apparatus  5 . Fixed to the working stage  100  is an apparatus which receives the retaining wedges  80 . These serve to secure or hold the pipe located in the well  103  during the loading of new pipes  78  from the pipe store  79 . 
     The roughneck  4  is arranged, in FIG. 10, on the base  1  and specifically in the lower region. In an alternative embodiment of the drilling rig (not shown), the roughneck is arranged not on the base but on the working stage  100 . 
     The two bases  1  have simplified pipe-handling apparatuses  30 , with which no lifting movement can be carried out. Such an arrangement is also necessary, for example, if, when the pipe racks  79  are standing upright, fingers which serve to retain or lock the pipes  78  are arranged to be movable vertically. In the normal case, however, pipe-handling apparatuses  30  are used which can perform lifting movements. 
     The pipe racks or pipe seating  79  are placed side by side on a stage  101 . They are filled with pipes  78 . 
     The bases  1  can be displaced via the movement apparatus  3  by means of the rollers  15  on rails  16  along the stage  101 . The bases  1  are also mounted to be rotatable via live rings  6 , in order to perform a 90° rotation, for example to remove a pipe  78  from the pipe rack  79 . The swivel apparatus  5  and the elevator  7  are dispensable in this case. It may be used, however, if oblique drilling is to take place at another drilling location, for example using only one drilling machine, or when the base  1  is to be erected for the first time. 
     FIG. 10 shows the right-hand drilling machine shortly before the drilling operation, where, for reasons of improved stability, it is releasably connected to the steel structure via the entry lid  70  and the locking apparatus  60 . The drill rod  14  is already in the well  103 , but the pipe-handling apparatus  30  has not yet been moved into the base. The second, left-hand drilling machine travels on the rails  16  directly backward, in other words away from the well (toward the left in the illustration), in order to load a new drill rod  78  from the pipe rack  79  by means of the pipe-handling apparatus  30 . The locking in the steel structure is released. 
     FIG. 11 describes another example of embodiment of a top drive guide means, in which the guide means is arranged within the base  1 . In this alternative embodiment, guide rails  22  are mounted in the base, and serve by means of the guide rollers  23  to receive the lateral guide plates  20 . The rollers  23  for the axial movement are mounted on these lateral guide plates  20 . These guide rollers  23  are, for example, roller-mounted and guide the complete structure in the linear axis. Junction plates  21  are welded onto the lateral guide plates  20  and serve to reinforce the receiving plates. The receiving plate  25  for the top drive is mounted on this welded structure. With the aid of a linear drive, a linear movement can be performed by the above-mentioned arrangement. This linear drive can be driven by chains, cables or a fluid engineering (hydraulic, pneumatic, etc.) solution. 
     A further embodiment according to the invention (not shown) envisages that a pipe-handling apparatus is arranged not directly on the base ( 1 ) but on the top drive housing ( 26 ) or the receiving plate ( 25 ) for the top drive housing ( 26 ) and moves with the latter coaxially to the longitudinal axis of the base ( 1 ). 
     Thus, while there have been shown and described and pointed out fundamental novel features of the present invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the present invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.