RU2231620C1 - Device for generating hydraulic pressure impulses in a well - Google Patents

Abstract

FIELD: oil and gas extractive industry.

SUBSTANCE: device has driving assembly made in form of screw gear mechanism. Its stator has inner screw teeth. Rotor has outer screw teeth. Also provided is flow interrupter including a valve connected to rotor and a stopper with through aperture for flow of fluid. Valve is connected to stopper by means of shaft mounted inside the stopper. Device has dog mechanism including a dog rigidly connected to the shaft, and a pusher, connected to the rotor. Stopper has additional connecting aperture for flow of fluid with cross-section lesser than cross-section of through aperture, and located relatively to through aperture and a stopper in such a way, that when stopper turns, connecting aperture remains open at whole range of stopper turn angle, at which it covers the through aperture.

EFFECT: higher efficiency of hydrodynamic influence on a bed due to providing for stability and controllability of generated hydraulic impulses.

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Description

The invention relates to the oil industry, and in particular to devices that provide enhanced oil recovery in production wells by creating hydraulic pressure pulses in the well.

A device is known for creating hydraulic pressure pulses in a well (See the book. Gadiev S. M. Use of vibration in oil production. - M .: Nedra, 1977, p. 50, Fig. 27).

The known device comprises a drive unit, a flow chopper and a support unit. The drive unit includes a fixed stator and a movable rotor. Attached to the lower end of the tubing string, the stator is cylindrical and has longitudinal slots on the lateral surface, made obliquely with respect to the generatrix of the cylindrical surface. A hollow tubular rotor is installed on the stator in the bearings of the support unit, also having longitudinal slots on the side surface inclined to the rotor generatrix in the opposite direction with respect to the stator slots. When flushing fluid is supplied, the rotor rotates in relation to the stator, while the stator slots periodically overlap with the inner surface of the rotor, which acts as a flow interrupter. Due to the blocking of the flow in the fluid, cyclic pressure fluctuations occur, which are transmitted to the annulus and act on the formation.

Known hydraulic downhole pulsator has a high frequency of hydraulic pulsations. The operation of the known pulsator is possible only on technically pure liquids. The wear of the rotor and stator when exposed to high fluid velocities and high fluctuations in the pulsating pressure leads to a deterioration in the energy characteristics of the drive unit and to a decrease in the pressure pulsations created by the flow chopper.

The closest in technical essence to the claimed solution is a device for creating hydraulic pressure pulses in a well (see RF patent No. 2151265, class E 21 B 28/00, 09/08/1998).

The said device includes a drive unit made in the form of a screw gerotor mechanism, the stator of which has internal helical teeth, and the rotor contains external helical teeth for interaction with helical teeth of the stator, a flow interrupter - a shutter connected to the rotor, a plug with a hole for the passage of fluid and an adapter to connect the device to the pipe string.

However, this device has the following disadvantage.

In the known device under the action of a hydraulic distortion moment, its rotor has an unstable orientation in the stator. During operation of the device, 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 away from the stator lining towards the convex-concave contact of the teeth, resulting in planetary rotor motions are superimposed on conical motions, mutual movements of the shutter rigidly connected to the rotor and the plug rigidly connected to the stator become chaotic, their flat surfaces facing each other STI lose parallelism with the gaps of the overlapping holes and hydraulic characteristics respectively generated pulses are random, and this phenomenon is exacerbated as the wear liner rubber stator. Constructive reduction of the gap in the device becomes dangerous, because in this case, there will be a chance that the overlap will touch the surface of the plug, which can cause accelerated wear and destruction of these parts.

The objective of the invention is to increase the efficiency of hydrodynamic effects on the reservoir by ensuring the stability and controllability of the generated hydraulic impulses.

The problem is solved due to the fact that in the device for creating hydraulic pressure pulses in the well, containing the drive unit, made in the form of a screw gerotor mechanism, the stator of which has internal helical teeth, and the rotor contains external helical teeth, a flow interrupter comprising a shutter connected with a rotor and a plug with a passage hole for fluid flow, the shutter is connected to the plug by means of a shaft installed inside the plug, while the device is equipped with a drive mechanism, with consisting of a leash, rigidly connected to the shaft, and a pusher connected to the rotor, and the plug has an additional choke hole for the fluid flow with a cross section smaller than the cross section of the passage hole and located relative to the passage hole and the shutter in such a way that when the shutter rotates, the shutter hole remains open in the entire range of the angle of rotation of the valve, at which it overlaps the passage hole.

The drawing shows a General view of a device for creating hydraulic pressure pulses.

The device comprises a sub 1 for connecting to a pipe string, a drive unit consisting of a stator 2 and a rotor 3 with a pusher 4, a heel 5 and a ball 6, a flow breaker including a plug 7 with a through hole A and a fitting B holes, a shaft 8 s installed in the plug fixed on it with a leash 9 and a shutter 10, pressed against the end plane of the plug by the spring 11. In the housing 12, the plug is fixed with fasteners 13.

A device for creating hydraulic pulses works as follows. When creating a reverse circulation, the fluid passes through the annulus, device and tubing. When passing through the device, the liquid from the bottom enters the housing 12, then through the bore hole A or, if at that moment it is blocked by a shutter, through the bore hole B enters the drive unit, rotates the rotor and through the heel hole enters the tubing and further on to the mouth. The rotation of the rotor together with the pusher is transmitted by the drive mechanism to the shaft and the damper, while the planetary movements of the rotor and the pusher are converted into the rotational movement of the lead, shaft and damper. The damper, sliding with its plane along the end plane of the plug associated with it, closes the bore hole at each revolution, as a result of which the entire fluid flow rushes through the nozzle hole and a sharp jump in hydraulic pressure occurs under the plug. The bore of the choke hole is selected based on the receipt of a hydraulic pulse of the required value when a fluid flow passes through it with a given volumetric flow rate. Structurally, the choke hole can be made with the possibility of preliminary adjustment of the cross-section, for example, contain interchangeable nozzles with holes of various diameters or contain several holes, the necessary part of which can be plugged.

The advantage of the claimed device over the known is:

- reliable closure of the through hole and the direction of the entire fluid flow through the nozzle hole;

- the ability to accurately control and control the parameters of the hydraulic pulses (amplitude and frequency) in a wide range by preliminary (before launching into the well) establishing the required flow area of the nozzle hole and the current (during operation in the well) variation in fluid flow rate.

Claims (1)

A device for generating hydraulic pressure pulses in a well, comprising a drive unit made in the form of a screw gerotor mechanism, the stator of which has internal helical teeth, and the rotor contains external helical teeth, a flow interrupter comprising a shutter connected to the rotor and a plug with a passage for the duct liquid, characterized in that the shutter is connected to the plug by means of a shaft mounted inside the plug, while the device is equipped with a pull mechanism consisting of a lead, rigidly knitted with a shaft, and a pusher connected to the rotor, and the plug has an additional choke hole for fluid flow with a cross section smaller than the cross section of the passage hole, and located relative to the passage hole and shutter in such a way that when the shutter rotates, the shutter hole remains open over the entire range of angles turning the damper at which it closes the passage hole.