RU2766241C1 - Downhole pumping unit - Google Patents

Abstract

FIELD: pump building.

SUBSTANCE: invention relates to submersible downhole pumping units and can be used for extraction of oil, water and other fluids from wells. Downhole pumping unit comprises a radial-plunger pump including a shaft with a through axial channel and radial holes, inlet and outlet valves, and an electric motor with hydraulic protection. Through axial channel of the shaft of the radial-plunger pump is equipped with an elastic diaphragm for supply of well fluid from the inlet valve to the outlet valve due to cyclic compression of the elastic diaphragm by plungers.

EFFECT: invention is aimed at improvement of reliability and energy efficiency of downhole pumping units.

3 cl, 7 dwg

Description

The invention relates to submersible well pumping units and can be used for the extraction of oil, water and other liquids from wells.

Centrifugal, screw and other downhole pumping units are known (see the site: www.borets.ru; www.novometgroup.com; www.rimera.com, etc.), including a pump, a gas separator (sand separator) and an electric motor with hydraulic protection.

The main disadvantage of these installations is that they all have low efficiency.

The closest in technical essence to the invention is a downhole pumping unit, known by patent RU 2732650 C1, IPC F04B 1/04 (2006.01), SPK F04B 1/04 (2020.08) dated February 26, 2020, containing a pump, inlet a module, a gas separator and an electric motor with hydraulic protection, wherein the pump is made as a radial plunger, and the axial channel of its shaft is made through, from one end of which the liquid enters the channel through the inlet valve, and from the other it leaves it through the outlet valve.

The main disadvantage of this invention is that when pumping downhole fluid with abrasive particles, the plunger pairs of the pump wear out quickly. In the process of wear of plunger pairs, the gaps between the plungers and their cylinders increase. This leads to an increase in the throttling of the liquid through the gaps, a decrease in pressure and efficiency. In addition, this installation is not capable of pumping liquid with gas without a gas separator due to the unacceptable ratio of useful and harmful volume.

The objective of the invention is to obtain a technical result, which is expressed in improving the reliability and energy efficiency of downhole pumping units.

The specified task in a pumping unit containing a radial plunger pump, including a shaft with a through axial channel and radial holes, inlet and outlet valves, and an electric motor with hydraulic protection, characterized in that the through axial channel of the shaft of the radial plunger pump is equipped with an elastic diaphragm for supplying well fluid from the inlet valve to the outlet valve due to the cyclic compression of the elastic diaphragm by the plungers, and the through axial channel is equipped with a device for venting gas into the annulus, and the radial holes in the through axial channel and the plungers are made in the form of an oval.

The scientific and technical analysis of the proposal and the prior art indicates that the proposed technical solution for a specialist does not follow explicitly from the prior art, while the features of the above set are interrelated, are in a causal relationship with the expected result and are necessary and sufficient for him receipt.

The invention is illustrated by drawings, where:

in fig. 1 shows a frontal section of the pumping unit;

in fig. 2 shows an enlarged fragment of the frontal section of a plunger pair and an elastic diaphragm in a free state;

in fig. 3 shows an enlarged fragment of the frontal section of a plunger pair and an elastic diaphragm in a compressed state;

in fig. 4 shows a cross section of a plunger pair and an elastic diaphragm in a free state;

in fig. 5 shows a cross section of a plunger pair and diaphragm in a compressed state;

in fig. 6 shows an enlarged fragment of the frontal section of a device for venting gas into the annulus;

in fig. 7 shows an enlarged fragment of a plunger pair made in the form of an oval.

A downhole pumping unit (see Fig. 1) consists of a radial plunger pump 1 and an electric motor with hydraulic protection 2. A radial plunger pump (see Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 and Fig. 7) contains a housing 3 with an oval sleeve 4, inside of which a shaft 5 with a through axial channel 6 is installed. 10 and cylinder 11 from abrasive particles, protecting them from premature wear. The plungers 10 are installed in the cylinder 11 with the possibility of axial movement in it. The cylinder 11 is installed in the radial hole of the shaft 5, which is made in the form of an oval (see Fig. 7). Accordingly, the plungers 10 and the cylinder 11 are also made in the form of an oval. The plungers 10 are equipped with rollers 12 (see Fig. 4 and Fig. 5), which, rolling over the inner surface of the oval sleeve 4 during rotation of the shaft 5, give a reciprocating motion to the plungers 10. In this case, the plungers 10 compress and unclench the elastic diaphragm 7 twice for one revolution of the shaft 5. The gas outlet into the annulus from the axial channel 6 provides a gas outlet device containing a check valve 13 and a set of throttles 14 (see Fig. 6).

The pumping unit operates as follows: when the pumping unit is immersed in the well, the well fluid fills the through axial channel 6 and the elastic diaphragm 7 through the inlets 15 and the inlet valve 8 (see Fig. 1, shown by arrows). When turning the shaft 5, the rollers 12, due to the oval shape of the sleeve 4, push the plungers 10 into the cylinder 11 (see Fig. 3 and Fig. 5). The plungers 10 compress the elastic diaphragm 7 and displace the liquid with abrasive particles from it through the exhaust valve 9 (see Fig. 1) and outlet channels 16 (see Fig. 6) into the tubing (not shown). In this case, the plunger pair 10 and 11 does not come into contact with abrasive particles and is not subjected to intense wear. Part of the liquid with gas is displaced into the annulus through the valve 13 (see Fig. 6, shown by arrows), throttles 14, channels 17 (shown by dotted line) and holes 18 in the housing 3. This increases the useful volume of liquid in the through axial channel 6 and provides achieving the required pressure. In this case, abrasive particles due to centrifugal force are deflected to the wall of the through axial channel 6 and do not enter the channels of the valve 13 and throttles 14. This prevents intensive wear of the device for gas removal. With further rotation of the shaft 5, as shown in Fig. 2 and FIG. 4, the plungers 10 are pulled out of the cylinders 11 under the action of centrifugal force. At the same time, the elastic diaphragm 7 straightens, and the well fluid again fills the through axial channel and the elastic diaphragm through the inlet valve 8. The cycle is repeated.

Excluding the contact of the plunger pair 10 and 11 with abrasive particles, the elastic diaphragm prevents premature wear of the plunger pair, eliminates the throttling of the fluid through its gaps. This increases the pressure, efficiency and reliability of the pumping unit as a whole. Gas removal to the annulus ensures the operation of the unit without a gas separator, which also increases its reliability and energy efficiency.

Thus, the invention allows to obtain a technical result, which is expressed in improving the reliability and energy efficiency of downhole pumping units.

Claims (3)

1. A downhole pumping unit containing a radial plunger pump, including a shaft with a through axial channel and radial holes, inlet and outlet valves, and an electric motor with hydraulic protection, characterized in that the through axial channel of the shaft of the radial plunger pump is equipped with an elastic diaphragm for supplying borehole fluid from the inlet valve to the outlet valve due to the cyclic compression of the elastic diaphragm by the plungers. 2. Downhole pumping unit according to claim. 1, characterized in that the through axial channel of the radial plunger pump is equipped with a device for venting gas into the annulus. 3. Downhole pumping unit according to claim 1, characterized in that the radial holes in the axial channel and the plungers are made in the form of an oval.

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