RU2255196C1 - Device for drilling deep perforation channels in cased well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device has body, provided with anchor, lowered on pipes to given depth, having guide and ring-shaped compaction of hydro-drive, and also made with possible displacement inside pipes and body by displacement means, hydraulic engine, passing through compaction, hollow of which is connected to destroying tool hollow, consisting of flexible shaft, provided with destroying head. Device also has tool for destroying casing column and tool for destroying rock, while hydro-drive consists of hollow leading and following shafts, made with possible rotation and longitudinal movement of the latter inside leading shaft until mounting in socket of leading shaft, forming non-pressurized couple cylinder-piston, while torque from leading shaft to following shaft is passed via ratchet gear, body has hydraulic channel, connecting guide hollow to ring-shaped well space, while on the side, opposite to output aperture of guide hydraulic deflector of piston-cylinder type is mounted on it, and in upper portion of body a cylindrical recess is present, made with possible hermetic mounting of leading shaft with rotation, while outside the body an anchor is mounted, being in threaded connection to sub connected to body, and engine is made with possible hermetic mounting in ring-shaped compaction, mounted above recess in body at a distance, lesser than total length of engine and leading shaft, while on the inner surface of body a stop is mounted made with possible interaction with shelves on outer surface of engine body. For making perforation channels in abrasive rocks rock-destroying tool is used, consisting of flexible shaft and chisel. As movement means flexible pipes are used, hollow of which connects to engine hollow.

EFFECT: higher reliability, higher efficiency.

7 cl, 5 dwg

Description

The invention relates to the field of oil and gas production and can be used for the secondary opening of productive formations of cased wells.

A device is known for drilling deep perforation channels in abrasive rocks, including a drilling unit consisting of a hydraulic motor and a drill, a drilling unit consisting of a flexible shaft and a bit, and a piston hydraulic actuator.

The device is lowered onto the pipes to the required depth, anchored, and the casing is destroyed by rotating the drill with a hydraulic motor with longitudinal movement by means of a piston. Then the drill is retracted to its original position, the drilling unit is moved down and a drilling unit is installed in its place, in which the bit connected to the flexible shaft is positioned coaxially with the hole obtained in the casing. A channel is drilled in rock with flushing by rotation of a flexible shaft equipped with a chisel, a hydraulic motor with a piston hydraulic drive for longitudinal movement. After drilling is completed, a flexible shaft with a chisel is pulled into the device body and the drilling and drilling blocks are moved up to their initial position. All drilling and drilling operations are carried out in seven successive cycles of injection and pressure relief at the wellhead, acting on the valves of the control unit, programmed for a specific sequence of operations and issuing hydraulic signals to the appropriate actuators.

To obtain each subsequent channel, the anchor is released, the column is moved to the required position and anchored again [1].

The device has the following disadvantages:

1. Due to the fact that the drill and the flexible shaft with the bit are returned by commands from the surface by applying and removing excess pressure in the absence of information from the operator about the drill and bit reaching the specified drilling and drilling depth, drilling of the casing to a depth less than the specified one can occur. Since a specialized bit is used for drilling, it may not provide for the destruction of the casing string.

2. To replace the drill and bit, it is necessary to raise and lower the device on the pipes, which requires a significant investment of time.

3. To obtain each perforation channel, it is necessary to position the body by moving the pipe string, which does not allow obtaining channels evenly spaced along the formation at great depths.

A device is also known for producing deep channels in a cased hole, folded by abrasive rocks. A device equipped with a guide descends to the required depth on the pipe string. Then, descend on flexible pipes inside the pipe string of the downhole motor connected to a destructive tool consisting of a flexible shaft provided with a destructive element. They apply a load and create excess fluid pressure in the cavity of the flexible pipes, providing rotation and longitudinal movement of the destructive tool, and the casing string is destroyed and the engine is lifted with the destructive tool. Inside the pipe string, a hydraulic monitor nozzle is lowered onto flexible pipes in the guide into the hole obtained in the casing. They create a high overpressure (up to 70 MPa) of water with the addition of a surfactant and produce rock destruction and obtaining a channel using the hydromonitor effect, after which the pipes with a nozzle are lifted. To obtain the next channel, it is necessary to relieve pressure and move the pipe string together with the housing [2].

The disadvantages of this device are as follows:

1. When a productive formation is destroyed by a high pressure jet of water, a very large amount of water is filtered into the formation, which reduces its reservoir properties.

2. When the casing is destroyed, the load on the destructive tool is regulated from the surface with the help of flexible pipes, which, with small created loads (about 2000 N), does not allow to precisely control it. This can lead to shaft fracture when exceeding the maximum permissible load or slow casing failure at low load.

3. There is no indication of the end of the casing collapse, which may lead to incomplete destruction.

4. The use of a jet jet with high flow rates can, due to the uneven interaction of the jet with the rock and the presence of reactive force, lead to significant deviations of the channel in any direction, including the channel exit beyond the reservoir.

5. The longitudinal and angular displacements of pipes produced on the surface, which are necessary to obtain each subsequent channel in the formation, do not correspond to the displacements of the body in the well, especially the curved one. This does not allow to obtain a uniform distribution of channels in the near-wellbore zone of the formation along the circumference and height.

6. In non-abrasive rocks, such as Cretaceous deposits, perforation channels of sufficient depth can be obtained with the tool used to break the casing. Under these conditions, the operation of lowering the tool to destroy the rock is not necessary.

The closest technical solution (prototype) to the proposed is a device for implementing the method of forming deep channels in a cased hole, which can be used for non-abrasive rocks. The device includes a housing that is run on pipes to the required depth with a guide and an o-ring of the hydraulic actuator and a hydraulic motor that runs through an annular seal and connected to a hollow flexible shaft equipped with a cutting head and used to make holes in the casing and channel non-abrasive rock. An anchor is used to fix the device casing in the casing [3].

The disadvantages of the device are as follows:

1. The load on the flexible shaft and the destructive head depends not only on the pressure in the pipe string, but also on the weight of the load-carrying cable, as well as its degree of tension. The last two parameters are interconnected and are difficult to adjust from the surface.

2. In the process of operation with an unsecured engine casing, due to the natural vibrations of the engine and the different directions of movement of the engine in the annular seal and a bent flexible shaft, the hydraulic drive seal may depressurize and, as a result, the rotation of the engine will stop, and the resulting reactive moment will rotate it and the whole tool in the opposite direction.

3. There is no mechanism to protect the shaft from overload, which can occur when the cutting head and flexible shaft are stuck by particles of cuttings, which can lead to shaft breakage.

4. The device does not provide control over the end of the drilling process of the perforation channel, which can lead to a channel with a depth less than the specified one, or idling.

5. Due to the stretching of the pipes and their interaction with the walls of the well, the movement of the pipes on the surface may not correspond to the movements of the body, so moving the body from the surface of the pipe string does not allow to obtain evenly spaced channels.

6. Since the casing of the device is not tightly pressed against the casing string, a deviation of the flexible shaft and the drilling channel from the normal to the surface of the casing string is possible.

7. The device can only be used to obtain channels in non-abrasive rocks, while most productive formations are composed of abrasive sandstones. As is known, the tool used to break the casing string quickly grinds and cannot be used effectively in abrasive rocks, and the tool used to break the abrasive rocks, for example, diamond, cannot be used effectively to break the metal of the casing string.

The objective of the invention is to obtain with high reliability and controllability evenly spaced along the helix of the channels of a given depth in the rocks of any abrasiveness.

To successfully solve this problem, a device for producing deep perforation channels in a cased hole, including a housing equipped with an anchor with a guide and an annular seal of a hydraulic actuator, lowered on pipes to a predetermined depth, and also a hydraulic motor made to move inside the pipes and housing through the seal, passes through the seal the cavity of which communicates with the cavity of the destructive tool, consisting of a flexible shaft provided with a cutting head, contains instr a casing string breaker and a rock breaking tool, and the hydraulic actuator consists of hollow drive and driven shafts that are capable of rotation and longitudinal movement of the latter inside the drive shaft prior to landing in the drive shaft socket, forming an unsealed cylinder-piston pair, and the rotation moment from the drive shaft to the driven shaft is transmitted through a ratchet mechanism, the housing contains a hydraulic channel communicating the cavity of the guide with the annular space of the well, while from the side a piston-cylinder type hydraulic deflector is installed therein opposite to the guide outlet, and in the upper part of the housing there is a cylindrical recess made with the possibility of tight fit with rotation of the drive shaft, and an anchor is installed outside the housing, which is in threaded connection with an adapter connected to the housing, and the engine is made with the possibility of tight fit in the annular seal installed above the recess in the housing at a distance less than the total length of the engine and leading of the shaft, while a stopper is installed on the inner surface of the casing, configured to interact with protrusions on the outer surface of the engine casing, and to obtain perforation channels in abrasive rocks, a rock destruction tool consisting of a flexible shaft and a bit is used, and as the means of movement are flexible pipes whose cavity communicates with the engine cavity.

These signs can eliminate the disadvantages inherent in the prototype through the use of a hydraulic feed of the tool, providing the specified load on the destructive tool, hermetic fixation of the engine and transmission of torque and load, protecting the tool from overload and indicating the end of the formation of the perforation channel.

In this case, the threaded connection of the anchor with the shank of the housing ensures uniform movement of the latter along the helix.

We are not aware of devices having a combination of the above characteristics, which means that the proposed device meets the requirements for inventions.

Figure 1 schematically shows the body of the device after anchoring. Figure 2 and 3 schematically shows the destruction of the casing string and drilling the channel in the rocks using a cable for hoisting operations. Figure 4, 5 shows an embodiment of the device in abrasive rocks using flexible pipes.

A device for drilling deep perforation channels in a casing well (FIG. 1) comprises a body 2 mounted on a pipe string 1 with a guide 3, the upper part of which has a coaxial guide 3 cylindrical recess 4, sealed with a seal 5. The cavity of the guide 3 communicates with an annular hydraulic channel 6 well space. In the housing 2 from the side opposite to the outlet of the guide 3 is also installed a hydraulic diverter 7 having a piston-cylinder design, the latter communicating with the pipe cavity 1 (not shown). The housing 2 is fixedly connected to the shank (sub) 8, which is in a threaded connection with a large pitch with the anchor 9. An annular seal 10 is installed in the upper part of the housing 2 coaxially to the cylindrical recess 4 for a tight fit of the hydraulic motor.

Using a lift 11 with a cable 12 (Fig.2,3), carry out the hoisting operations inside the pipes 1. The cable 12 is connected to a hydraulic motor 13, for example, a screw connected to a hydraulic actuator 14. The hydraulic actuator 14 consists of a hollow lead 15 and a driven 16 shafts in a spline connection by a spring-loaded ratchet mechanism 17. The driven shaft 16 having a thickening 18 is arranged to longitudinally move inside the drive shaft 15 until it fits into the socket 19 of the drive shaft 15, forming an unsealed cylinder-piston pair. The driven shaft 16 is connected to a tool 20 (FIG. 2) for breaking the casing 22 and a tool 21 (FIG. 3) for breaking the rock 23. The tool 20 consists of a flexible shaft 24 and a breaking head 25, for example a drill, and the tool 21 consists from a hollow flexible shaft 26 of greater length and a bit 27 of a smaller diameter, for example, diamond for drilling abrasive rocks. The required fracture depth of the casing 22 and rock 23 is determined by the length of the longitudinal movement of the driven shaft 16 from the top point to the planting of its thickening 18 in the socket 19. To compensate for the reactive moment of the engine 13 there is a stopper 28 on the inner surface of the pipe, and 13 on the outer surface of the engine protrusions 29 made with the possibility of interaction. O-ring 10 is installed above the cylindrical recess 4 at a distance less than the total length of the engine and drive shaft.

For tripping operations, flexible pipes 30 are used (Fig. 4,5). The cavity of the flexible pipes 30 communicates with the hydraulic pump (not shown) and with the cavity of the engine 13. The remaining structural elements: the housing 2, the hydraulic actuator 14, as well as the tool 20 and the tool 21 correspond to the embodiment of the device shown in figures 2 and 3.

The device operates as follows.

On the pipes 1, the device body 2 is lowered to the abrasive rock 23 depth, connected by the shank 8 with the anchor 9. The body 2 and the pipes 1 are fixed with the anchor 9.

Using the lift 11 on the cable 12 inside the pipes 1, the engine 13 is lowered with a hydraulic actuator 14 and a tool 20 (figure 2). The descent is made up to the stop of the drive shaft 15 of the hydraulic actuator 14 in a cylindrical recess sealed by a seal 5. In this position, the engine 13 is sealed from above by an annular seal 10, and the stopper 28 and the protrusions 29 are at the same level. The tool 20 abuts against the casing 22, and the driven shaft 16 is in the upper position.

Overpressure is pumped into the pipe cavity 1, which ensures that the housing 2 of the device is pressed against the casing 22 by the diverter 7 and the drive shaft 15 is rotated by the engine 13, which transmits the torque through the splined connection of the ratchet mechanism 17 from the drive 15 to the driven 16 shaft. Pressure from the engine overhead 13 is applied to the thickening 18 of the driven shaft 16, creating a longitudinal load. A flexible shaft 24 connected to the driven shaft 16 transmits a rotational moment and a load to the destructive head 25, thereby destroying the casing 22. A part of the fluid flow passes through the hollow shafts 15, 16 and 24 and the destructive head 25 and exits through the annular space of the drilling channel, and the other part of the flow, passing through the annular gap between the thickening 18 of the driven shaft 16 and the inner walls of the drive shaft 15, enters the annular space of the well through the hydraulic channel 6.

When the torque exceeds the maximum permissible value, the ratchet mechanism 17 is activated, interrupting the spline connection between the drive 15 and the driven 16 shafts and preventing the flexible shaft 24 from being broken.

After drilling a hole in the casing 22, the thickening 18 of the driven shaft 16 sits in the socket 19 of the driving shaft 15, blocking the fluid flow exiting through the hydraulic channel 6. A sharp increase in fluid pressure is observed, which is fixed on the day surface. This serves as a signal for the end of the destruction of the casing string 22.

Relieve fluid pressure. Lift inside the pipes 1, the engine 13 with the drive 14 of the tool 20 and replace it with a tool 21 for rock destruction, containing a flexible shaft 26 of greater length with a bit 27 of a smaller diameter.

Make a descent on the cable 12 inside the pipes 1 of the engine 13 with the drive 14 and the tool 21 until the drive shaft 15 fits into the recess 4. The bit 27 enters the hole in the casing 22, abutting the rock 23, and the driven shaft 16 is in the upper position. Excess pressure is created in the pipe cavity 1, ensuring that the device body 2 is pressed against the casing 22, rotationally driven by the engine 13 and longitudinally moved by the hydraulic actuator 14 of the tool 21 and drilling with flushing the channel in the rock 23.

After drilling a channel of a given depth, a thickening 18 of the driven shaft 16 sits in the socket 19 of the driving shaft 15, the pressure increases sharply, signaling the end of drilling. Relieve fluid pressure and raise the engine 13 with the drive 14 of the tool 21 to the surface.

To obtain the next perforation channel, the pipe string 1 is rotated. The shank 8, freely rotating along the thread of the anchor 9 with the corresponding step, moves along the helix along with the housing 2, which allows one to obtain perforation channels located along the helix.

The perforation channel in non-abrasive rocks, such as Cretaceous deposits, can be obtained in one run with a tool 20 for the destruction of the casing string.

When using flexible pipes 30 (Figs. 4, 5), the excess pressure pumped into their cavities is transferred to the cavity of the engine 13 and hydraulic actuator 14, providing a drive for rotation and longitudinal movement of the tool 20 or tool 21. The procedure for perforating channel formation is as described higher. Using flexible pipes 30 also carry out tripping.

After the device is completed, the pipe string 1 is tensioned and, at a certain load (about 5 tons), the anchor 9 breaks down, acquiring its original transport diameter.

Information sources.

1. Canadian Patent CA 2238782.

2. US Patent No. 5853056.

3. RF patent No. 2190089, publ. 04/09/2002, Bull. Number 27.

Claims (7)

1. A device for drilling deep perforation channels in a cased hole, including a housing with a guide provided with an anchor, run on pipes to a predetermined depth, made with the ability to move inside the pipes and the housing by a moving means passing through the ring seal of the housing, a hydraulic motor, the cavity of which communicates with the cavity destructive tool, characterized in that the hydraulic actuator includes hollow drive and driven shafts, made with the possibility of rotation and longitudinal movement of the lead of the shaft inside the drive shaft before landing into the socket of the latter, forming an unsealed cylinder-piston pair, and transmitting the torque from the drive shaft to the driven shaft via a ratchet mechanism, the housing has a hydraulic channel for communicating the guide cavity with the annular space of the well, from the side opposite to the output a guide hole, a piston-cylinder-type hydraulic deflector is installed in the housing, and in its upper part there is a cylindrical recess made with a tight fit with rotation of the drive shaft, wherein the anchor is placed outside the housing and connected to it by a threaded connection by means of an adapter, and the hydraulic motor is sealed to fit into the annular seal mounted above the cylindrical recess in the housing at a distance less than the total length of the engine and drive shaft, a stopper is installed on the inner surface of the housing, configured to interact with protrusions on the outer surface of the hydraulic motor housing. 2. The device according to claim 1, characterized in that for the destruction of the casing, the destructive tool includes a flexible shaft and a destructive head. 3. The device according to claim 1, characterized in that to obtain perforation channels in abrasive rocks, the destructive tool includes a hollow flexible shaft and a bit. 4. The device according to claim 1 or 2, characterized in that the means of movement is made in the form of a cable connected with a hydraulic motor. 5. The device according to claim 1 or 3, characterized in that the means of movement is made in the form of a cable connected with a hydraulic motor. 6. The device according to claim 1 or 2, characterized in that the means of movement is made in the form of flexible pipes, the cavity of which communicates with the cavity of the hydraulic motor. 7. The device according to claim 1 or 3, characterized in that the means of movement is made in the form of flexible pipes, the cavity of which communicates with the cavity of the hydraulic motor.

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