RU2750791C1 - Apparatus for drilling out compressed plug in borehole - Google Patents

Abstract

FIELD: petroleum and gas industry.

SUBSTANCE: invention relates to the petroleum and gas industry, namely to apparatuses for drilling out compressed plugs in a borehole. The apparatus is comprised of a tool for applying axial force - a pipe column, a screw non-self-braking mechanism containing a hollow cylindrical shaft and a hollow cylindrical body, and a rock cutting tool, connected in series. The pipe column is rigidly connected with the hollow cylindrical body, configured to move axially downward. The rock cutting tool configured to rotate around the axis thereof is rigidly connected to the hollow cylindrical shaft from below. The apparatus is equipped with a hollow stem inserted into the hollow cylindrical shaft from above. The upper part of the hollow stem is screwed into the hollow cylindrical body. The upper end of the hollow stem is equipped with a ball seat. The upper end of the hollow cylindrical shaft is equipped with a shutoff piece for the axial movement of the hollow cylindrical body. The hollow stem is spring-loaded upward from the shutoff piece to the inner upper end of the hollow cylindrical body. The rock-cutting tool is made in form of a sleeve with pointed blades on the bottom and flushing channels between the blades. The lower end surface of the sleeve is equipped with a babite alloy.

EFFECT: reliability of operation of the apparatus, quality of drilling out of the compressed plug, efficiency of removing the drilled cuttings from the borehole during the process of flushing are increased, the operational capabilities are expanded.

1 cl, 3 dwg

Description

The invention relates to the oil and gas industry, and in particular to a device for drilling out sealed plugs in a well.

In domestic practice, when drilling out sealed plugs, in particular sand or proppant plugs, various mechanical or hydraulic rotors are used, through which the rotation of the pipe string lowered into the emergency well is carried out, for example, drill pipes, tubing, steel drill pipes, with rock cutting tools, for example, a milling cutter, a chisel, etc. (Amirov A.D. et al. Reference book on the current and capital repairs of oil and gas wells - M .: Nedra, 1979. - pp. 26-28).

To date, most of the wells have entered the late stage of development, which is characterized by low wellhead parameters and formation water inflow to the bottom of the well. The use of traditional methods of drilling out a packed plug using rotors or downhole motors to rotate the pipe string implies killing the well, which at this stage of development can lead to the well being retired from production. To carry out workover without killing the well, a coiled tubing unit can be used, while the main problem is the inability to rotate the coiled tubing.

A device is known for removing compacted plugs from wells using a hydraulic drill, lowered into a well on a rope (Amirov A.D. et al. Reference book on the current and overhaul of oil and gas wells - M .: Nedra, 1979, p. 187). The hydraulic drill contains a chisel, a bailer, a plunger pump, a plunger, a pump body, a side valve, a bailer body, a ball valve, and a central pipe.

The disadvantage of the known device is the low efficiency of destruction of the plug, as well as its overall size, which does not exclude the possibility of sticking the hydraulic drill in the well. For the same reason, it will not be possible to drill out the sealed plug in one run, since the body of the thief of the hydraulic drill is limited in volume. Another disadvantage of the hydraulic drill is the cable, which gets tangled in the pipe string and is not able to transmit the axial force to the tool.

Known thief for cleaning the bottom of the well (patent RU No. 136079, publ. 27.12.2013), containing sub, container, check valve, centering funnel.

The disadvantage of the known device is that it is not effective for drilling out the sealed plugs, and its descent is carried out exclusively on the tubing string.

The closest in technical essence and the achieved result is a device for drilling out a sealed plug in a well (patent RU No. 162846, publ. 06/27/2016 ) , containing a series-connected means for applying axial force, a screw non-self-braking mechanism and a rock-breaking tool, a screw non-self-braking mechanism contains a driving link - a hollow cylindrical shaft connected to the means for applying axial force, and the driven link is a hollow cylindrical body mounted for rotation around its axis, while a rock-cutting tool is fixed in the lower part of the hollow cylindrical body, said means for applying an axial force is a pumping string compressor pipes, drill string or flexible string (GT).

The disadvantages of the device are:

- firstly, the low reliability of the device, since the inner cavity of the hollow cylindrical body is filled with grease. If drilled cuttings in the form of sand or proppant get into the inner cavity, this will lead to jamming of the non-self-braking mechanism, and, as a result, to the failure of the device;

- secondly, the low quality of drilling the sealed plug, since a bit is used as a rock cutting tool, which, due to its design, does not provide a high-quality deepening when drilling (deepening) a sealed plug at low rotation speeds created by a non-self-braking mechanism, in comparison with screw downhole motors. This does not allow high-quality loosening of the compacted proppant or sand plug;

- thirdly, the low efficiency of the removal of drilled cuttings from the well during the flushing process. This is due to the fact that during direct flushing, the particles of drilled cuttings when lifting with flushing fluid along the annulus due to their weight settle back onto the drilled sealed plug, and in the case of back flushing, for example, when the device is suddenly stopped or when the device is removed from the well, the drilled particles sludge settles back into the well, but from the inner space of the pipe string;

- fourth, the limited functionality of the device in wells with asphaltene-resin-paraffin deposits, in deviated wells and small-diameter wells (with diameters of 114, 120, 140 mm). This is due to the fact that during the operation of the device, i.e. When creating cyclic axial loads, the body rotates, which is damped by friction forces against the borehole walls, while the friction forces either completely extinguish the rotation of the body and the rock cutting tool rigidly connected to it, or the rotational speed of the rock cutting tool is minimal, which does not ensure drilling out of the compacted plug.

The technical objectives of the invention are to create a device that improves the reliability of the device, the quality of drilling the packed plug, the efficiency of removing the drilled cuttings from the well during the flushing process, as well as expanding the functionality of the device.

The set technical problems are solved by a device for drilling out a sealed plug in a well, which contains a series-connected means for applying an axial force - a pipe string, a screw non-self-braking mechanism containing a hollow cylindrical shaft and a hollow cylindrical body, and a rock cutting tool.

The novelty is that the pipe string is rigidly connected to the hollow cylindrical body through the coupling with the possibility of axial movement downwards, while the rock cutting tool is rigidly connected from below to the hollow cylindrical shaft, which can rotate around its axis, while the device is equipped with a hollow rod inserted from above into hollow cylindrical shaft, and the upper part of the hollow rod is screwed into the hollow cylindrical body, and the upper end of the hollow rod is equipped with a seat for the ball, and the upper end of the hollow cylindrical shaft is equipped with a stop for the axial movement of the hollow cylindrical body, while the hollow rod is spring-loaded upward from the travel stop to the inner upper end of the hollow cylindrical body, the rock-cutting tool is made in the form of a coupling with pointed feathers from the bottom and flushing channels between the feathers, while the lower end surface of the coupling is equipped with a babite alloy, and in the working position when unloading the weight of the pipe string onto the device the pipe string, the hollow cylindrical body and the hollow rod rigidly connected to it move downward relative to the rotating hollow cylindrical shaft with the rock breaking tool, compressing the spring until the travel stop interacts with the inner upper end of the hollow cylindrical body, and when the pipe string is lifted, the spring expands, while the hollow the cylindrical shaft with the rock cutting tool rotates in the opposite direction relative to the hollow cylindrical body until the travel stop of the hollow cylindrical rod interacts with the inner lower end of the hollow cylindrical body, and the device takes its initial position.

FIG. 1 schematically shows a device for drilling a sealed plug in a well, which shows the location of a hollow cylindrical shaft in the extreme upper position.

FIG. 2 schematically shows a device for drilling a sealed plug in a well, which shows the location of a hollow cylindrical shaft in the lowest position.

FIG. 3 shows a view A of the device.

A device for drilling out a sealed plug in a well contains a series-connected means for applying an axial force - a pipe string 1 (Fig. 1-2) (for example, a GT string with an outer diameter of 44.5 mm with a wall thickness of 4 mm), a screw non-self-braking mechanism 2 and a rock cutting tool 3. The screw non-self-braking mechanism 2 contains a driving link - a hollow cylindrical shaft 4 and a driven link - a hollow cylindrical body 5.

As a screw non-self-braking mechanism 2, screw drives with low sliding friction can be used.

Column GT 1 through the coupling 6 is rigidly connected to the hollow cylindrical body 5 with the possibility of axial movement downward.

From below to the hollow cylindrical shaft 4, the rock cutting tool 3 is rigidly connected, having the ability to rotate around its axis. The device is equipped with a hollow rod 7 inserted from above into the hollow cylindrical shaft 4. The upper part of the hollow rod 7 is screwed into the hollow cylindrical body 5 by means of a threaded connection 8.

The upper end of the hollow stem 7 is equipped with a seat 9 for a ball 10.

The upper end of the hollow cylindrical shaft 4 is equipped with a travel stop 11 for the axial movement of the hollow cylindrical body 5. The travel stop 11 is made in the form of an outer annular recess at the upper end of the hollow cylindrical shaft 4.

The hollow rod 7 is spring-loaded by means of a spring 12 upward from the travel stop 11 to the inner upper end 13 of the hollow cylindrical body 5. The hollow rod 7 hydraulically connects the hollow cylindrical shaft 4 and the hollow cylindrical body 5 during the flushing process when drilling out the sealed plug.

Rock-cutting tool 3 is made in the form of a sleeve 14 with pointed feathers, for example, in the amount of four pieces 15 ', 15 ", 15"', 15 "" (Fig. 1-3) from the bottom and flushing channels 16 ', 16 ", 16"' , 16 "" (Fig. 1-2) between the feathers 15 ', 15 ", 15"', 15 "". The lower end surface of the sleeve 14 is equipped with a babite alloy 17 (FIGS. 1-3).

In the working position, when unloading the weight of the pipe string 1 (Fig. 2) onto the device, the pipe string 1, the hollow cylindrical body 5 and the hollow rod 7 rigidly connected to it move downward relative to the rotating hollow cylindrical shaft 4 with the rock breaking tool 3, compressing the spring 12. In while the rock cutting tool 3 rotates, the compacted plug (sandy, proppant) is drilled out.

The compression of the spring 12 occurs before the travel stop interacts with the inner upper end 13 of the hollow cylindrical body 5, after which the rotation of the hollow cylindrical body 5 and the rock cutting tool 3 connected to it stops.

When lifting the pipe string 1, the spring 12 is expanded, while due to the return force of the spring 12, the hollow cylindrical shaft 4 with the rock cutting tool 3 rotates in the opposite direction until the travel stop of the hollow cylindrical shaft 4 interacts with the inner bottom end 18 (Fig. 1-2) of the hollow cylindrical body 5, while the device is in its original position.

Unauthorized overflows of flushing fluid with particles of drilled sludge during the operation of the device are excluded by O-rings 19 and 20.

Hollow rod 7 paired with a hollow cylindrical shaft 4, thanks to the seal 19 and 20, ensure the tightness of the screw non-self-braking mechanism 2 during operation, in addition, the hollow rod 7 eliminates the need to fill the internal cavity of the device with grease.

The device works as follows.

The proposed device is lowered into the emergency well (not shown in Figs. 1-3), up to the "head" of the sealed plug, for example, sandy or proppant,, for example, using a mobile lifting unit using, as indicated above, the GT 1 string (see. Fig. 1) with a diameter of 44.5 mm with a wall thickness of 4 mm as a means of applying an axial force F.

When the device rests on the sealed plug, the translational movement of the means for applying the axial force F (GT columns 1) is converted into the rotational movement of the rock cutting tool 3.

Circulation of fluid in the well is caused by backwashing (shown by arrows in Fig. 1). The liquid used is, for example, waste water with a density of 1080 kg / m ³ .

Under the action of the axial force F, the driving link - the hollow cylindrical body 5 is locked and its translational movement downward. The driven link - the hollow cylindrical shaft 4 begins to rotate, driving the rock cutting tool 3 in rotary motion.

Rock-cutting tool 3, made in the form of a sleeve 14 with pointed blades 15 ', 15 ", 15"', 15 "", for example with a height h (see Fig. 1) equal to 15 cm deepens and drills (loosens) the compacted plug, while the fluid flow created by the backwash carries out the drilled sludge of the sealed plug through the flushing channels 16 ', 16 ", 16"', 16 "" between the feathers 15 ', 15 ", 15"', 15 "" through the inner spaces of the rock cutting tool 3, a hollow cylindrical shaft 4, a hollow rod 7, lifting the ball 10 from the seat 9 and the inner space of the string of flexible pipes 1 to the surface (into the gutter container in Fig. 1-3 is not shown)

In this case, the rotating hollow cylindrical shaft 4 descends down the helical surface of the non-self-braking mechanism 2, compressing the spring 12, until the travel stop 11 of the hollow cylindrical shaft 4 with its upper end interacts with the inner upper end 13 of the hollow cylindrical body 5 (see. Fig. 2), after which the rotation of the hollow cylindrical body 5 and the rock cutting tool 3 connected to it stops.

In addition, the inner upper end 13 of the hollow cylindrical body 5 limits the compression stroke of the spring 12. As a result, excessive force applied by the spring 12, which can lead to breakage of the spring, is limited.

The GT column 1 is lifted up by 2-3 meters, while due to the return force of the spring 12, the hollow cylindrical shaft 4 is unwound in the opposite direction relative to the hollow cylindrical body 5 along the helical surface of the non-self-braking mechanism 2, while the rock cutting tool 3 together with the rotating hollow cylindrical shaft 4 move downward relative to the stationary hollow cylindrical body 5, until the travel stop 11 of the hollow cylindrical shaft 4, with its lower end, interacts with the inner lower end 18 of the hollow cylindrical body 5. The device takes its initial position (see Fig. 1) ... This occurs one cycle of operation of the device, while the backwash is continued.

Further, as described above, repeated cycles of work with the proposed device are performed until the destruction of the sealed plug, while backwashing is performed continuously during the period of operation of the device. The number of operation cycles of the device depends on the height of the compacted (sandy, proppant) plug, the stroke length - L of the hollow cylindrical rod relative to the hollow cylindrical body 5. For example, work to remove the compacted plug is performed in 8 above-described cycles.

After the completion of the planned work, backwashing is stopped, while the ball 10 sits on the seat 9, which excludes the back-settling of the drilled sealed plug back into the well. The device is removed from the well.

The reliability of the device is increased, since the inner cavity of the hollow cylindrical body is not filled with grease, and the tightness of the non-self-braking mechanism 2 is provided by O-rings 19 and 20.

The quality of drilling out the compacted plug is improved, since a special tool is used as a rock cutting tool 3, made in the form of a coupling 14 with pointed feathers, for example, in the amount of four pieces 15 ', 15 ", 15"', 15 "" from the bottom and flushing channels 16 ' , 16 ", 16" ', 16 "" between feathers 15', 15 ", 15" ', 15 "". Pointed feathers 15 ', 15 ", 15"', 15 "" as indicated above with a height h (see Fig. 1) equal to 15 cm, which provides a high-quality loosening of the compacted surface of the drilled plug, in contrast to the bit. The lower end surface of the sleeve 14 is equipped with a babite alloy 17 to increase the durability of the rock cutting tool 3.

The efficiency of the removal of drilled cuttings from the well during the flushing process is increased. This is ensured by the operation of the device in the backwash mode and the ball with a seat included in the device, therefore, when the device suddenly stops operating, for example, when the volume of the flushing fluid is consumed during the backwash process) or when the device is removed from the well, the ball 10 sits under its own weight on the saddle 9, due to which the drilled cuttings do not settle back into the well from the inner space of the GT 1 string, but remain inside the GT string and are disposed of into a trough tank when the GT 1 is raised to the surface.

The functionality of the device is expanded in wells with asphaltene-resin-paraffin deposits, in deviated wells, as well as in small-diameter wells (with diameters of 114, 120, 140 mm). Since in the proposed device, the rotation on the rock cutting tool 3 is performed not due to the rotation of the hollow cylindrical body 5, but due to the hollow cylindrical shaft 4 when the hollow cylindrical body 5 is not rotating, which makes it possible to eliminate the influence of friction forces on the rotating hollow cylindrical body, which eliminates the loss revolutions of rotation of the rock cutting tool and structurally makes it possible to reduce the outer diameter of the hollow cylindrical body 5 when drilling out the sealed plug.

The proposed device for drilling out a packed plug in a well allows:

- to improve the reliability of the device;

- to improve the quality of drilling the sealed plug;

- to increase the efficiency of the removal of drilled cuttings from the well during the flushing process;

- to expand the functionality of the device.

Claims (1)

A device for drilling out a sealed plug in a well, containing a series-connected means for applying axial force - a pipe string, a screw non-self-braking mechanism containing a hollow cylindrical shaft and a hollow cylindrical body, and a rock breaking tool, characterized in that the pipe string is rigidly connected to the hollow cylindrical body through a coupling with the possibility of axial movement downward, while the rock cutting tool is rigidly connected from below to the hollow cylindrical shaft, which can rotate around its axis, while the device is equipped with a hollow rod inserted from above into the hollow cylindrical shaft, and the upper part of the hollow rod is screwed into the hollow cylindrical body, moreover, the upper end of the hollow rod is equipped with a seat for the ball, and the upper end of the hollow cylindrical shaft is equipped with a stop for the axial movement of the hollow cylindrical body, while the hollow rod is spring-loaded upward from the travel stop to the inner upper end of the hollow cylinder casing, the rock-cutting tool is made in the form of a coupling with pointed blades at the bottom and flushing channels between the blades, while the lower end surface of the coupling is equipped with a babite alloy, and in the working position when unloading the weight of the pipe string onto the device, the pipe string, the hollow cylindrical body and rigidly connected to with it, the hollow rod moves downward relative to the rotating hollow cylindrical shaft with the rock cutting tool, compressing the spring until the travel stop interacts with the inner upper end of the hollow cylindrical body, and when the pipe string is lifted, the spring expands, while the hollow cylindrical shaft with the rock cutting tool rotates in the opposite direction relative to the hollow cylindrical body until the travel stop of the hollow cylindrical rod interacts with the inner lower end of the hollow cylindrical body, and the device takes its initial position.

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