RU2507367C1 - Device for fixing of pipe string with downhole motor - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: device to fix pipe string with downhole motor comprises pipe string downed via thrust flange in the well casing string. Pipe string is composed of several pipes with screw downhole motor and rock destruction tool at its end. Top pipe of said string features square cross-section and supports two semi-rings with rectangular cutouts at the centre. Said semi-rings are tightened by the flange from above while bushing with cut segment is rigidly fitted between said semi-rings and pipe casing thrust flange. Note here that said bushing is rigidly clamped to semi-rings from above and, from below, to well casing thrust flange. Note here that two-sided mouth sealer is fitted in said thrust flange to seal the space between casing and pipe string. In operation of downhole motor, pipe string can display axially without rotation through the length of pipe casing top tube square cross-section.

EFFECT: ruled out back rotation of pipe string at perception of reaction moment resulted from downhole motor casing, longer life, higher efficiency.

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Description

The invention relates to the oil and gas industry and can be used as a reactive moment compensator for the operation of a downhole motor.

Known downhole screw motor (V.F. Abubakirov and others. "Drilling equipment": a Handbook in 2 volumes of T.2. "Drilling tool". - M .: OJSC "Publishing house" Nedra ", 2003, with .109-110), containing a motor stator with cavities adjacent at the ends to the high and low pressure chambers, a rotor-screw through which torque is transmitted to the rock cutting tool.

The disadvantage of this device is that the rotor during rotation interacts through the working fluid with the stator (housing). This leads to the appearance of a reactive moment, which is transmitted through the housing to the string of tubing or drill pipe, which is a reactive moment compensator from a downhole screw motor. However, this results in reverse rotation of the drill string, which is extinguished on the walls of the drill string and in the drive mechanisms located on the surface, which leads to damage to the borehole walls and has a negative effect on the drive mechanisms, reducing the resource of their work.

The closest in technical essence and the achieved result is a device for compensating the reactive moment of a downhole screw motor, including a downhole motor (patent RU No. 2283936, IPC E21B 4/02, published on September 20, 2006 in bull. No. 26), comprising a housing with a chamber for pumping the working agent and a rotor mounted on bearings in the housing cavity.

A downhole screw motor with a rock cutting tool is lowered into the well on a drill pipe string that senses the reactive moment of the downhole motor housing. During the operation of the downhole motor, the active moment is used to rotate the rock cutting tool, and the reactive moment is perceived by the drill string, causing them to rotate.

The disadvantages of this device are:

- firstly, due to the perception of the drill pipe of the reactive moment, its reverse rotation occurs, which is partially extinguished on the walls of the casing of the well and in the drive mechanisms located on the surface, which leads to damage to the walls of the casing of the well and has a negative effect on the drive mechanisms, reducing the resource of their work;

- secondly, due to the perception of the drill pipe string of the reactive moment spent on the reverse rotation of the pipe string, the efficiency of the downhole screw motor is reduced by 15-20%;

- thirdly, to collect the process fluid that rises at the wellhead through the annulus, it is necessary to dig out the barn, make it waterproof, which requires additional costs and is harmful to the environment.

The technical objectives of the proposal are to increase the efficiency of the downhole motor, increase the efficiency of the device by eliminating the reverse rotation of the pipe string when perceiving the reactive moment from the body of the downhole motor.

The tasks are solved by a device for fixing a pipe string with a downhole motor, including a pipe string formed of several pipes, lowered through a support flange into the casing of the well, with a screw downhole motor and a rock cutting tool at the end.

What is new is that the upper pipe of the pipe string is square and has two half rings with rectangular cutouts in the center covering the upper pipe of the square cross section, the half rings are rigidly tightened by the flange on top, the sleeve with the cut-out pipe is rigidly mounted between the half rings and the casing support flange segment, while the top of the sleeve is rigidly fixed with half rings, and the bottom with the supporting flange of the casing of the well, with a double-sided casing installed in the supporting flange of the well wellhead sealant for sealing the space between the casing string and the pipe string, and the pipe string during the operation of the downhole screw motor has the possibility of tight axial movement without rotation by the length of the square section of the upper pipe string pipe.

Figure 1 schematically shows the proposed device.

Figure 2 shows a section aa in the horizontal plane.

A device for compensating the reactive moment of a downhole screw motor includes a string of pipes 3 with a downhole motor and rock cutting tool (not shown in FIGS. 1 and 2) lowered through the support flange 1 (FIG. 1) into the casing 2 of the well (not shown in FIGS. 1 and 2). As the string of pipes 3 (FIG. 1), a tubing string of 73 mm diameter is used, which is a plurality of pipes connected to each other by means of couplings. As a downhole screw motor, for example, an engine of the DZ-106MR.7 / 8.37 brand is used.

The upper pipe 4 (Figs. 1 and 2) of the pipe string 3 (Fig. 1) is made with a square section, and there are semicircles 5 and 6 (Fig. 2) with rectangular cutouts 7 and 8, centrally covering the square upper pipe 4 sections. On top of the half rings 5 and 6 are rigidly tightened by the flange 9 (see figure 1) by means of bolts 9 '; 9 "; ... 9 ⁿ (partially shown in Fig. 1).

Below, between the half rings 5 and 6 and the supporting flange 1, a sleeve 10 with a cut-out segment 11 is rigidly mounted. On top of the sleeve 10 is rigidly fixed with half rings 5 and 6, for example, by means of a hairpin connection (Fig. 1 is shown conditionally).

From the bottom, the sleeve 10 (Fig. 1) is rigidly connected to the support flange 1 of the well casing 2, for example, by means of a hairpin connection (Fig. 1 is shown conditionally).

In the supporting flange 1 (Fig. 1) of the well casing 2 between the casing 1 and the pipe string 3, a two-sided wellhead sealant 12 is installed, equipped with an external sealing element 13, and an internal sealing element 14 made, for example, in the form of rubber rings.

In the process of running a downhole screw motor, the pipe string 3 has the ability to tightly axially move without rotation by the length of the square section of the upper pipe 4 of the pipe string 3.

The length L of the square section is equal to the length of one pipe with the exception of the nipple and coupling joints and is, for example, 8.7 m.

Half rings 5 and 6 fix the upper tube 4 of square cross section, excluding the rotation of the pipe string 3 during operation of the downhole screw motor.

The device operates as follows.

Before mounting the device for fixing the pipe string with the downhole motor through the support flange 1 (Fig. 1) of the casing string 2, the pipe string 3 with the downhole motor and the rock cutting tool are lowered into the well at the end. The downhole screw motor comprises a housing with a chamber for pumping a working agent mounted on bearings in the cavity of the rotor housing.

As a rock cutting tool, for example, a three-cone bit is used to remove a cement bridge or a drillable packer (a removable object) or a universal cutting device for removing part of a casing string. The downhole motor is lowered into the well as a rock cutting tool drive.

The pipe string 3 is lowered until the rock cutting tool is in the upper interval of the removed object (not shown in FIGS. 1 and 2), after which the proposed device is mounted on the support flange 1 of the well (as shown in FIGS. 1 and 2). The upper end of the upper pipe 4 (Fig. 1) of the pipe string 3 is connected to the discharge line 15 of the pump unit (not shown in Figs. 1 and 2). The annular space 16 (figure 1) is tied with a groove capacity (not shown in figures 1 and 2). Start pumping the pumping unit of the process fluid, for example fresh water with a density of 1000 kg / m ³ through the pipe string 3 (figure 1). The flow of the process fluid drives the downhole motor.

In the process of running a downhole motor, the reactive moment from the body of the downhole motor is transmitted to the pipe string 3, which leads to a reverse rotation of the pipe string 3. The active moment from the rotor of the downhole motor is used to rotate the rock cutting tool, which destroys the deleted object, and as it is removed of the object, the pipe string 3 moves downward, while the process fluid with the material of the distant object rises up through the annular space 16 and enters the groove capacity (n and Figs. 1 and 2 are not shown), from where the process fluid enters the suction line and the circulation of the process fluid through the downhole screw motor continues.

Thanks to the double-sided wellhead seal 12, the wellhead is sealed in the support flange 1 of the casing string 2, while the process fluid from the annulus 16 is sent directly to the groove tank, which eliminates the need for digging the barn to collect the process fluid and its waterproofing, and therefore additional costs, and also does not harm the environment.

The maximum tight axial movement of the pipe string 3 down without rotation is possible by the length of the square section of the upper pipe 4 of the pipe string 3, i.e. to a length of 8.7 m.

The proposed device for fixing a pipe string with a downhole motor allows you to prevent reverse rotation of the pipe string from the perception of reactive moment from the body of the downhole motor during its operation, which eliminates damage to the walls of the column of vertical and deviated wells, as well as negative impact on the drive mechanisms, preserving their resource work, with a 15-20% increase in the efficiency of a downhole screw motor.

Claims (1)

A device for fixing a pipe string with a downhole motor, including a pipe string formed from several pipes lowered through a support flange into the casing of the well, with a screw downhole motor and a rock cutting tool at the end, characterized in that the upper pipe of the pipe string is square in cross section, and it has two half rings with rectangular cutouts in the center, covering the upper tube of square section, on top of the half rings are rigidly tightened by a flange, below between the half rings and the supporting flange about of the garden string, a sleeve with a cut-out segment is rigidly mounted, with the top of the sleeve being rigidly fixed with half rings, and the bottom with the support flange of the well casing, with a double-sided wellhead sealant installed in the support flange of the well casing to seal the space between the casing and the pipe string, and the pipe string during the operation of the downhole screw motor has the possibility of tight axial movement without rotation by the length of the square section of the upper pipe of the pipe string.

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