RU2280748C1 - Bottomhole drilling string assembly for inclined and horizontal well drilling with the use of downhole screw motor - Google Patents

Abstract

FIELD: well drilling equipment, particularly equipment for directional drilling.

SUBSTANCE: bottomhole assembly comprises drilling string, drilling bit, downhole screw motor and telescopic system installed between lower drilling string pipe and downhole screw motor. The telescopic system comprises cylinder provided with orifices in lower part thereof and connected with drilling string and hollow piston located in the cylinder. The hollow piston is attached to downhole screw motor body. The bottomhole assembly comprises fixed valve made as bush with elastic shank and installed in the cylinder over cylinder orifices. The elastic shank has conical surface to permit piston passage in the shank and annular grooves adapted to receive annular sealing members made of elastomeric material.

EFFECT: increased service life due to improved bottomhole assembly reliability.

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Description

The invention relates to techniques for drilling oil and gas wells.

The known layout of the downhole motor, which descends into the well on a drill pipe string [1].

Also known is the layout of the bottom of the drill string for drilling directional and horizontal wells with a downhole motor, consisting of a drill string, a bit, a downhole motor and installed between the bottom pipe of the drill string and the downhole motor of a telescopic system including a cylinder made in the lower part with holes and connected to the drill string, and a hollow piston located inside it, connected to the engine housing, while on the outer surface of the piston is installed Sealed element [2].

The specified arrangement provides the creation of a hydraulic load on the engine casing with its subsequent transfer to the bit, regardless of the position of the engine in the well.

The disadvantage of this arrangement is that the sealing element located on the outer surface of the piston during its movement along the inner surface of the cylinder passes through the holes in the cylinder body and undergoes significant wear and, as a result, the rapid destruction of the sealing element.

The objective of the present invention is to increase the service life of the layout by increasing the reliability of its operation.

The problem is solved due to the fact that the layout of the bottom of the drill string for drilling directional and horizontal wells with a downhole motor, consisting of a drill string, a bit, a downhole motor and a telescopic system including a cylinder installed between the bottom pipe of the drill string and the downhole motor, made in the lower part with openings and connected to the drill string, and the hollow piston located inside it, connected to the engine housing, is provided with Vision spool formed as a sleeve with an elastic liner and a cylinder mounted above its openings, the shank to enter it, the piston is formed with a conical surface and with annular grooves in which are arranged sealing rings of elastomeric material.

Figure 1 shows the layout of the bottom of the drill string.

Figure 2 shows a telescopic system with a rod located in the upper position.

Figure 3 shows a telescopic system with a rod located in the lower position.

Figure 4 shows the spool with an elastic shank.

The inventive arrangement (figure 1) consists of drill pipes 1 of a telescopic system 2, a downhole screw motor 3 and a bit 4.

The telescopic system (figure 2, 3) includes a cylinder 5 with holes 6, a spool 7. Inside the cylinder there is a piston 8 having an interchangeable nozzle 9. The reactive torque that occurs when the downhole motor is connected to the rod is perceived by the protrusions 10, located inside the cylinder 5 and included in the reciprocal grooves on the shank of the piston 8.

Spool 7 is shown in figure 4. It consists of a metal cylindrical sleeve 11, mounted motionlessly in the cylinder body 5, an elastic cone 12 of a conical shape with sealing rings 13 located inside it, providing a movable tight connection between the rod and the sealing sleeve.

The layout of the bottom of the drill string is as follows.

When a flushing fluid is supplied, under the influence of a pressure differential in the engine and nozzle, the piston 8 moves downward, creating axial force on the engine and on the bit. After the piston 8 leaves the cylinder body by a certain amount, holes 6 open in the cylinder 5 and the working fluid is discharged into the annulus. At the same time, the pressure drop acting on the layout of the bottom of the drill string decreases, and this process is fixed by instruments on the surface. After that, the drilling tool is fed, and the loading cycle is repeated.

The proposed arrangement can be effectively used for directional and horizontal drilling to maintain a given axial load on the bit, especially when drilling using a flexible continuous pipe as a drilling tool.

INFORMATION SOURCES

1. Baldenko D.F., Baldenko F.D., Gnoev A.N. Screw downhole motors. M .: Nedra, 1999.S. 302-310.

2. Baldenko D.F. etc. The layout of the bottom of the drill string for drilling directional and horizontal wells with a downhole screw motor. RF patent №2164582 with priority 16.06.1999, cl. E 21 B 7/08 (prototype).

Claims (1)

Layout of the bottom of the drill string for drilling directional and horizontal wells with a downhole motor, consisting of a drill string, chisel, downhole motor and a telescopic system installed between the bottom pipe of the drillstring and the downhole motor including a cylinder made in the lower part with holes and connected with a drill string, and a hollow piston located inside it, connected to the engine housing, characterized in that it is equipped with a fixed spool, in complements a sleeve with an elastic liner and a cylinder mounted above its openings, the elastic shank to enter it, the piston is formed with a conical surface and with annular grooves in which are arranged sealing rings of elastomeric material.

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