RU2232245C1 - Screw pit-face engine - Google Patents

Abstract

FIELD: drilling equipment engineering.

SUBSTANCE: device has stator with inner screw teeth, rotor with outer screw teeth, number of which is by one less than number of stator teeth, and rotor axis is displaced relatively to stator axis for eccentricity value which is equal to half of radial height of teeth, supporting assembly including a shaft, axial and radial supports, device for transferring rotation and axial load from rotor to shaft of supporting assembly, sub with bottom in which side aperture is made and assembly for forming hydraulic pressure impulses. Sub bottom has central and additionally side apertures of different diameter: greater - for passing of fluid flow, lesser for excluding dead position of engine. Assembly for forming hydraulic pressure impulses is made in form of sub mounted in central bottom aperture and roller cylinder sealed by gland compaction, in upper portion of which cylinder above bottom of sub a valve is placed made with apertures and connecting pipes and plugs mounted therein. On lower portion of roller cylinder under bottom of sub a carrier is placed mounted with capability for interaction with pusher placed on end of rotor.

EFFECT: higher effectiveness of rock destruction due to providing for stability and controllability of formed hydraulic impulses.

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Description

The invention relates to drilling equipment, namely to downhole motors for drilling wells.

Known downhole screw motor comprising a sub, a stator with internal helical teeth, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, a support node including a shaft, axial and radial bearings, and a device for transmitting rotation and axial load from the rotor on the shaft of the support node, while the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth (RF Patent No. 2011778 of 09.21.89).

A disadvantage of the known downhole screw motor is that when sinking rocks of increased hardness, the efficiency of the well deepening process decreases due to a decrease in the mechanical drilling speed due to the static nature of the axial force transmitted from the engine rotor to the rock cutting tool.

The closest technical solution adopted for the prototype is a downhole motor containing a sub, a stator with internal helical teeth, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, the support node, including the shaft, axial and radial bearings, made with the possibility of axial movement of the shaft and the rotor connected to it, and a device for transmitting rotation and axis th load from the rotor to the shaft support unit, wherein the sub configured with a hole and create a hydraulic pressure pulse unit (RF Patent №2166053, Cl. E 21 B 4/02 of 02.08.99 g).

A disadvantage of the known downhole screw motor is as follows. During its operation under the influence of a hydraulic distortion moment, its rotor has an unstable orientation in the stator, as a result of which the upper part of the rotor in the direction of fluid flow is pressed against the rubber lining of the stator in the area of the engagement pole (the area of the convex-concave contact of the teeth), and the lower part of the rotor tends to move from the stator lining towards the convex-concave contact of the teeth, as a result of which conoidal motions, mutual movements of the lower end of the sub with with the aperture and the upper end of the rotor with protrusions become complex and chaotic, the gap between the protrusions and the end surface of the sub in the hole zone and, accordingly, the hydraulic characteristics of the generated pulses are random in nature, which reduces the efficiency of using the dynamic component of the axial load on the bit when the rock is destroyed. This disadvantage increases with the wear of the rotor and stator along the mating surfaces.

The objective of the invention is to increase the efficiency of destruction of rock by ensuring the stability and controllability of the generated hydraulic impulses.

The problem is solved due to the fact that in the well-known downhole motor containing a stator with internal helical teeth, the rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial the height of the teeth, the support node, including the shaft, axial and radial bearings, a device for transmitting rotation and axial load from the rotor to the shaft of the support node, sub with a bottom in which a side hole is made and a unit for generating hydraulic pressure pulses.

The bottom of the sub has central and additional side holes of different diameters: the larger one for the passage of fluid flow, the smaller one to eliminate the dead position of the engine, and the unit for creating hydraulic pressure pulses is made in the form of the bottom of the sub installed in the central hole and sealed with a stuffing box seal, in the upper part which is located above the bottom of the sub shutter, made with holes, with fittings or plugs installed in them, while on the bottom of the roller under the bottom m sub placed carrier, installed with the ability to interact with a pusher located on the end of the rotor.

The invention consists in the following. The implementation of the unit for creating hydraulic pressure pulses in the form of a roller installed in the sub with a stuffing box seal with the upper part of the damper, in which the holes are made with fittings or plugs installed in them, and a carrier is installed on the lower part of the roller, which is installed with the possibility of interaction with the pusher located on the end of the rotor, and the implementation of the Central and optionally side holes of different diameters provides for the rotation of the roller with a flap periodically shut off the fluid flow STI and thereby creating water hammer gidroimpulsov like acting on the rotor of the screw motor. At the same time, through the use of nozzles of different diameters or plugs, it is possible to select the mode of rock destruction with the corresponding impulses.

Figure 1 shows a screw downhole motor in longitudinal section; figure 2 is a longitudinal section of a node for creating hydraulic pressure pulses; figure 3 is a view a in figure 2; figure 4 is a section bB in figure 2.

The downhole screw motor comprises a sub 1 with a bottom 2, in which a central hole 3 is made for accommodating a stuffing box 4 with a thrust nut 5 and a roller 6 (FIG. 2). In addition to the central hole 3, several holes of different diameters were made in the bottom of the sub: two working holes of a larger diameter 7 and 8 for passing the main stream pumped through the fluid engine, and two bypass holes 9 and 10 to eliminate the dead position of the engine when the main working holes are larger in diameter 7 and 8 are closed by a shutter 11. The shutter 11 mounted on the roller 6 has openings 12 for accommodating interchangeable fittings 13 or plugs in them. A carrier 14 is installed at the lower end of the roller 6. A pusher 16 is placed on the end of the rotor 15 having external helical teeth, on which the sleeve 17 is freely put on to reduce friction when the pusher comes in contact with the carrier 14. The pusher 16 transmits rotation from the sleeve 17 and the carrier 14 the rotor 15 through the roller 6 of the shutter 11. The stator 18 has internal helical teeth, the number of which is one more than the number of teeth of the rotor. The rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth. A support unit 19 is connected to the stator, including a housing 20 and a shaft 21 mounted in the housing 20 using axial 22 and radial 23 bearings. The lower end of the rotor 15 and the upper end of the shaft 21 are connected by a device 24 for transmitting rotation and axial load.

Screw downhole motor operates as follows. The working fluid supplied from the surface through the drill pipe string enters sub 1 and enters the upper engine cavity through openings 7, 8 and 9, 10. Under the influence of the pressure of the washing liquid, the engine starts to rotate the rotor 15, making a planetary movement, rolling around its internal teeth along the internal teeth of the stator 18. The planetary movement of the rotor 15 is converted to the coaxial rotation of the shaft 21 of the support unit 19 by means of a device 24 for transmitting rotation and axial load. The shaft 21 rotates inside the housing 20, while the axial load from the weight of the drill pipe string is transmitted to the rock cutting tool through a sub 1, a stator 18, a rotor 15, a housing 20 of the support assembly 19, an axial support 22 and a shaft 21 of the support assembly.

The rotor of the engine 15 acts with the help of a pusher 16 with a sleeve 17 on the carrier 14 and causes the roller 6 to rotate and the shutter 11 screwed on it.

When the shutter 11 rotates, it periodically closes either the working holes of a larger diameter 7 and 8, or the bypass holes of a small diameter 9 and 10.

When you open the holes 7 and 8, a water hammer occurs, which is reflected on the bottom of the well through the rotating rotor 15 of the engine.

During the closing of the openings 7 and 8, so as not to completely block the flow of fluid through the engine, small openings 9 and 10 remain open.

The strength of the drilled rocks varies in different areas. For example, in the Volga region, the rocks are mainly carbonate; in Western Siberia, in the geological section, there are many clay rocks.

Therefore, when drilling through carbonate strata, the openings 7 and 8 are blocked by plugs installed in the holes of the damper. When the engine is running, hydraulic pulses with this option are more powerful. Drilling clay rocks may not require powerful hydraulic pulses to destroy them. In such cases, fittings may be inserted into the openings of the shutter 7 and 8.

The use of the proposed downhole screw motor will increase the efficiency of rock destruction due to hydraulic pulses on the rotating shaft of the engine, and will also allow you to choose the optimal mode of application of hydraulic pulses to the rotating shaft 15 by changing the nozzles 13 on the plug, or vice versa.

The application of the proposed downhole screw motor will allow:

- increase the power of hydraulic pulses that create effective tensile stresses in the rock and which are comparable or even higher than the rock's tensile strength;

- selection of fittings or installation of one or two plugs expand the range of effective use of a downhole screw motor when drilling various types of rocks, increasing the mechanical speed of penetration;

- increased drilling speed is the result of effective tensile stresses in combination with mechanical indentation of teeth or bit cutters.

Claims (1)

A downhole screw motor comprising a stator with internal helical teeth, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, a support unit including an axial shaft and radial bearings, a device for transmitting rotation and axial load from the rotor to the shaft of the support unit, a sub with a bottom in which a side hole and a unit for creating hydraulic pressure pulses are made, excellent The fact that the bottom of the sub has central and additional side holes of different diameters: the larger one for the passage of fluid flow, the smaller one to eliminate the dead position of the engine, and the unit for creating hydraulic pressure pulses is made in the form of the bottom of the sub installed in the central hole and sealed with a stuffing box seal , in the upper part of which, above the bottom of the sub, there is a shutter made with holes with fittings or plugs installed in them, while on the lower part and a roller under the bottom of the sub placed a carrier installed with the possibility of interaction with a pusher located at the end of the rotor.

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