RU2232244C1 - Pit-face engine - Google Patents

Abstract

FIELD: drilling equipment engineering.

SUBSTANCE: device has driving section and spindle section consisting of body, hollow output shaft, axial support, radial support. In body of spindle section opposite to ports for liquid flow into hollow output shaft not moveably relatively to the body a through flow bushing is placed serving as additional radial support and made with inner channels. Ports for flow of washing liquid in hollow output shaft and inner channels of through flow bushing are placed in such a way that bushing periodically covers ports for liquid flow during rotation of hollow output shaft. Axial support of hollow output shaft is spring-loaded.

EFFECT: higher drilling productiveness due to more effective destruction of rock by chisel during forcing of, except rotational, also additional axial vibrations(strikes) onto the chisel and better washing of pit-face of slurry by working fluid due to its feeding into pit-face area in form of portions forming impulse hydraulic strikes in drilling area.

2 cl, 4 dwg

Description

The invention relates to drilling equipment, namely to downhole motors, designed for drilling and repair of oil and gas wells.

Known downhole motors, consisting of a motor and spindle sections, including a housing, a hollow output shaft, axial support and radial bearings (see books: Calculation, design and operation of turbodrills, M .: Nedra, 1976, pp. 50-56; Screw downhole motors, M .: Nedra, 1999, p. 18, p. 32-35).

During operation of these downhole motors, the bit is only given a rotational movement when flushing the bottomhole zone with a relatively constant, unchanged flow rate of the working fluid. The destruction of the rock occurs by sequential cutting of its layers during the rotation of the bit.

Known downhole screw motor according to patent No. 2110660 (publ. July 20, 2002), comprising a working body section including a stator and an eccentrically mounted rotor inside it, a spindle section containing a housing, a hollow output shaft, axial and radial bearings, a coupling with windows for the passage of flushing fluid through the hollow output shaft mounted on the hollow output shaft, and the kinematic assembly of the rotor with the hollow output shaft of the spindle section, and it contains an additional radial support mounted on soy extension sleeve in the area below the windows for the passage of flushing fluid, for the interaction of the outer surface of the coupling with the inner surface of the additional radial bearings, and the additional radial bearing is fixed in the housing motionless.

During operation of this downhole motor, the bit is only given a rotational movement when flushing the bottomhole zone with a relatively constant, unchanged flow rate of the working fluid. The destruction of the rock occurs by sequential cutting of its layers during the rotation of the bit.

The present invention solves the problem of increasing drilling productivity due to more efficient destruction of the rock by the bit when giving the bit, in addition to rotational, additional axial vibrations (impacts) and better washing of the bottom from the sludge by the working fluid due to its entering the bottomhole zone in the form of portions that create pulsed water hammer in the drilling zone.

To achieve the technical result, in a downhole motor containing a motor section and a spindle section, consisting of a housing, a hollow output shaft, an axial support, radial bearings, in the housing of the spindle section opposite the windows for fluid flow into the hollow output shaft, the flowing motionless is relative to the housing a sleeve serving as an additional radial support, made with internal channels, while windows for passing washing fluid into the hollow output shaft and internal channels of the flow sleeve are laid such that the sleeve overlaps periodically when turning the hollow output shaft for fluid flow window, wherein the axial support of the hollow output shaft may be biased.

Distinctive features of the proposed downhole motor from the above, closest to it, is that in the housing of the spindle section opposite the windows for the flow of fluid into the hollow output shaft, the flow sleeve, which serves as an additional radial support, made with internal channels, is stationary with respect to the housing, and at the same time, the windows for passing the flushing fluid into the hollow output shaft and the internal channels of the flowing sleeve are located so that the sleeve periodically overlaps when turning the floor th output shaft box for fluid flow, wherein the axial support of the hollow output shaft may be biased.

Due to the presence of these features, drilling productivity is improved due to more efficient rock destruction with a chisel. In addition to the rotary bit, additional axial vibrations (impacts) are also added; washing of the bottom from the sludge with the working fluid improves due to its entry into the bottomhole zone in the form of portions that create pulsed water hammer in the drilling zone.

The proposed downhole motor is illustrated by the drawings shown in figures 1-4:

figure 1 shows the engine section of the downhole motor (a variant of the downhole screw motor);

figure 2 - spindle section of the downhole motor;

figure 3 is a section aa in figure 1 (the position of the hollow output shaft when the duct is open);

figure 4 is a section aa in figure 1 (the position of the hollow output shaft when the duct is closed).

The downhole motor comprises a motor section (Fig. 1) and a spindle section (Fig. 2) consisting of a housing 1, a hollow output shaft 4, an axial support 7, radial bearings 10. In the casing of the spindle section 1 of a downhole motor of rotary-impact action above the upper radial bearings 2 motionless sleeve 3 is located relative to the housing with channels on its inner surface, which serves as an additional radial support, and the hollow output shaft 4 or the coupling 5 have windows 6 for the flow of drilling fluid into the hollow outlet to the bit, which when rotating the hollow output shaft from the engine section periodically overlap the inner surface of the flow sleeve 3 (Fig.3), and the axial support 7 of the hollow output shaft is spring-loaded with Belleville springs 8, allowing axial movement of the hollow output shaft relative to the housing by 1- 2 mm within the limits of spring stiffness and axial force on the bit.

The work of the downhole motor is as follows. The working fluid (drilling fluid) from the mud pump under pressure up to 20 MPa enters through the drill string to the bottom of the drill string to the engine section of the downhole motor and has a pressure before entering the engine section P ₁ (Fig. 1). After passing through the motor section, the hydraulic fluid causes rotation of the rotor 9 (turbine shaft) and has a spindle inlet section pressure P _2. When the position of the hollow output shaft relative to the flow sleeve in the position when the duct is closed (figure 4), the pressure P ₂ rises sharply and tends to be equal to the pressure P ₁ due to inertia (kinetic energy of the flow). The flow rate of the working fluid in the engine sections is from 0.5 (D-42) to 50 l / s (D1-240, T12RT-240). Then, when the rotor (turbine shaft) is rotated, the hollow output shaft is rotated, the rotor (turbine shaft) and the hollow output shaft are rigidly interconnected by a torsion bar or coupling relative to the flow sleeve rigidly fixed in the housing, and windows for the flow of working fluid into the hollow output are opened shaft to the bit. The pressure P ₂ decreases sharply, the pressure difference P ₁ and P ₂ (differential pressure) on the engine section changes, the fluid flow increases spasmodically. Then the process is repeated, i.e. the working fluid duct is blocked by the flow sleeve. When the hollow output shaft is rotated one revolution, a 4-fold overlap and opening of the working fluid flow occurs.

The number of channels of the flow sleeve and the holes of the hollow output shaft (coupler) vary depending on the drilling conditions (rock hardness and the required energy and frequency of impact). The number of flow overlaps can be from 1 to 12 or more times per revolution of a hollow output shaft. A periodic change in the pressure drop in the engine section causes a periodic change in the hydraulic buoyancy axial force acting on the rotor (turbine shaft), and since the rotor (turbine shaft) is rigidly connected to the hollow output shaft by means of a torsion bar or a coupling, and the hollow output shaft has the possibility of axial movement within the stiffness of the Belleville springs limiting its movement, then the hollow output shaft and bit also receive variable axial displacements ( shocks) with a frequency proportional to the number of channels of the flow sleeve and the rotational speed of the hollow output shaft, and the working fluid enters the drilling zone in the form of wave portions (pulsed water hammer o), providing better flushing (removal) of the destroyed rock (sludge) from the bottom, increases drilling productivity due to more efficient destruction of the rock.

Claims (2)

1. A downhole motor comprising a motor section and a spindle section, consisting of a housing, a hollow output shaft, an axial support, radial bearings, characterized in that in the housing of the spindle section opposite the windows for fluid flow into the hollow output shaft, the flowing motionless is relative to the housing a sleeve that serves as an additional radial support, made with internal channels, while the windows for passing the washing liquid into the hollow output shaft and the internal channels of the flow sleeve are located so that ulka periodically closes by rotating the hollow output shaft box for fluid flow. 2. The desktop engine according to claim 1, characterized in that the axial support of the hollow output shaft is spring-loaded.

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