RU2505665C1 - Device for regulation of water cone in well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device contains a pump launched into casing string at pipe string with shank end underneath and connected to connecting tube; in the well there are two delivery channels, at that one channel is for oil delivery while the other one is for water delivery from stratum to the well. Channel inputs are located at different levels while outputs are directed to pump suction side. Shank end is equipped from outside with packer installed in casing string at the level of water-oil contact and radial holes of shank end are located higher than packer. At that below radial holes a hollow blind plug is inserted into shank end; connecting tube is inserted into the plug, at that tube can be moved along axis and fixed. However fixation of connecting tube in regard to shank end is made by split locking ring of circular section which is installed in inner groove of the hollow blind plug; this ring fixes the connecting tube in semicircular notches at outside surface of the tube. At that channel for oil delivery is formed by inner space of the casing string upwards packer, radial holes of the shank end and space between the shank end and connecting tube. Channel for water delivery is formed by inner space of the casing string downwards packer and inner space of the connecting tube. Inputs of both channels are located opposite perforated holes in water- and oil-bearing parts of stratum while outputs are directed to pump suction. Due to regulation of water and oil extraction the suggested device also allows preventing mixing of water and oil in process of their raising in the pipe string and producing of product that does not require subsequent separation into different phases; it also allows reducing probability of water-oil emulsion and paraffin deposition in result of fast transfer from water extraction to oil extraction.

EFFECT: ability of water and oil extraction regulation when level of water-oil contact changes in the well during operation process, producing product that does not require subsequent separation into different phases and probability of water-oil emulsion and paraffin deposition at inner surface of pipes.

3 dwg

Description

The invention relates to the field of oil industry, in particular to a means of lifting fluid from a well.

A device is known for implementing a method for controlling a water cone during oil production under two-phase filtration conditions (II Kleschenko, R.Yu. Kuznetsov, Yu.V. Sukhachev. News of Universities, Oil and Gas, 1998, No. 6, p.21- 26.), consisting of a mechanical valve connecting the tubing internal cavity alternately with the casing cavity above or below the packer installation site.

The disadvantage of this device is the non-automatic operation of the control valve and the need to reorient the working parts of the valve at times when the water cut of the product reaches a predetermined percentage and when oil appears in the selected aqueous phase.

Known input device of the downhole pump (patent RU No. 1782294, IPC 8 F04D 13/12, publ. 12/15/1992, bull. No. 46) for regulating the water cone in the well, allowing you to control the water cone in the well, containing two inlet pipes, the inputs of which are located at different levels, and the outputs are connected through a connecting device on opposite sides of it to the pump inlet pipe. The suction pipe of the pump is connected to the upper U-shaped portion of the connecting tube.

The disadvantages of this device are:

- firstly, the products raised by the pump from the well to the surface require subsequent separation into separate phases;

- secondly, there is a high probability of the formation of oil-water emulsions and deposition of paraffin in the well, which is due to the long transition from pumping water to oil;

- thirdly, low oil recovery with bottom water.

The closest in technical essence and the achieved result is the input device of the downhole pump (patent RU No. 2123613, IPC F04B 47/00, F04D 13/12, publ. 12/20/1998., Bull. No. 35) for regulating the water cone in the well, containing a pump lowered on a string of elevator pipes into an oil well, in which there is oil and water entering the well from the reservoir, while a liner in the form of a pipe is connected to the bottom of the pump, the lower end of which is connected to the connecting pipe at a distance calculated from its bottom, and also two inlet pipes, inputs which are located at different levels, and their outputs are connected by a connecting pipe, while it is equipped with an additional channel connected to the connecting pipe of the inlet pipes.

The disadvantages of this device are:

- firstly, the low efficiency associated with the fact that during the operation of the device during the development of formations with plantar water, the level of water-oil contact (WOC) constantly changes (rises or falls), and the device does not have the ability to control the volume of oil and water withdrawal, therefore, oil and water are mixed at the pump inlet;

- secondly, due to the fact that the work does not take into account the change in the level of VNK, the products raised by the pump from the well to the surface require subsequent separation into separate phases;

- thirdly, the long duration of the transition from pumping water to oil, so there is a high probability of the formation of water-oil emulsions and deposition of paraffin in the well.

An object of the invention is to create a device design that allows you to adjust the volume of oil and water withdrawal when changing the level of water-oil contact (WOC) in the well during operation, as well as obtaining products on the surface of the well that do not require subsequent separation into separate phases and reduce the likelihood of the formation of oil-water emulsions and paraffin deposits on the inner surface of the pipes.

The problem is solved by a device for regulating the water cone in the well, comprising a pump lowered into the casing of the well on a pipe string with a liner bottom connected to the connecting pipe, as well as two supply channels located in the well, one channel for supplying oil, the other channel for the supply of water entering the well from the reservoir, the channel inputs are located at different levels, and the outputs are directed to the pump intake.

What is new is that the pipe string shank is provided externally with a packer installed in the casing of the well at the oil-water contact level and radial holes above the packer, and a hollow plug is rigidly installed in the shank below the radial holes, into which the connecting pipe is sealed with axial movement and fixation while fixing the connecting tube relative to the shank is carried out using a split retaining ring of circular cross section installed in the inner point of the hollow plug and fixing the connecting pipe in semicircular notches made on the outer surface of the connecting pipe, wherein the oil supply channel is formed by the inner space of the casing above the packer, the radial holes of the liner and the space between the shank and the connecting pipe, and the channel for supplying water is formed the inner space of the casing below the packer and the inner space of the connecting pipe, and the inputs of both channels are located opposite the perforation holes in the water-bearing and oil-bearing parts of the reservoir, and the outlets are directed to the intake of the pump.

In figures 1-3 shows a diagram of the proposed device.

A device for regulating a water cone in a well comprises a pump 1 (see FIG. 1), lowered into a casing 2 of a well on a pipe string 3 with a liner 4 from the bottom.

The device also contains two inlet channels 5 and 6 located in the well. Channel 5 is for supplying oil, and another channel 6 is for supplying water to receive pump 1, which enter the well from formation 7.

The shank 4 of the pipe string 3 is provided externally with a packer 8 installed in the casing 2 of the well at the level of the oil-water contact (WPC) 9 and the radial holes 10 above the packer 8. In the shank 4 below the radial holes 10, a hollow plug 11 is tightly installed, which is hermetically sealed axial movement and fixation of the connecting tube 12.

Fixation of the connecting tube 12 (see FIGS. 1 and 2) relative to the shank 4 is carried out using a split retaining ring 13 of circular cross section, mounted in the inner groove 14 of the hollow plug 11, and fixing the connecting tube 12 in semicircular notches 15, made on the outer surface of the connecting tube 12.

Channel 5 (see Fig. 1) for supplying oil is formed by the inner space 16 of the casing 2 above the packer 8, the radial holes 10 of the liner 4 and the space 17 between the liner 4 and the connecting pipe 12 above the packer 8.

The channel 6 for supplying water is formed by the inner space 18 of the casing 2 below the packer 8 and the inner space 19 of the connecting tube 12.

The inputs of both channels 5 and 6 are located opposite the upper 20 and lower 21 perforations in the water-bearing and oil-bearing parts of the formation 7, respectively, and the outputs are directed to the intake of the pump 1.

The operation of the device is as follows.

The equipment as shown in FIG. 1 is lowered into a well filled with a process fluid (water). The level of KSS 9 is horizontal.

Initially, pump 1 (see Fig. 1), for example, a NSV-32 borehole sucker-rod pump, pumps water from a well through a pipe string 3. At the same time, oil enters through the upper perforations 20 and accumulates in the inner space 16 between the liner 4 and the casing 2. The difference between the hydrostatic pressures in the inner space 16 and the space 17 of the channel 6 does not allow oil pump 1 to enter intake 22.

Water enters the intake 22 of the pump 1 from the aquifer of the formation 7 through the lower perforations 21 and then the channel 6 for supplying water, formed by the inner space 18 of the casing 2 below the packer 8 and the inner space 19 of the connecting pipe 12, from where it enters the intake 22 of the pump 1 which pumps water through a pipe string 3 at the wellhead.

The water cone (not shown in FIGS. 1-3), is lowered, and when it reaches the lower perforations 21, oil and water will begin to flow through the channel 6 through the interior of the connecting tube 12. The density of the liquid in the inner space 19 of the connecting tube 12 becomes less than the density of water in the space 17 and the water flows over the inner space 19 of the connecting tube 12 into the under-pouch space 18 of the well.

The flow of oil begins, which through the upper perforations 20, and channel 5, i.e. through the inner space 16 of the casing 2 above the packer 8, the radial holes 10 of the liner 4 and the space 17 is received by the pump 1, which pumps oil through the tubing string 3 at the wellhead.

The cone of water rises, and the flow of oil through the lower perforations 21 stops. Water fills the inner space 18 of the casing 2 below the packer 8 and the inner space 19 of the connecting pipe 12, however, cannot be received at the intake 22 of the pump 2 due to the difference in hydrostatic pressure in the inner space 19 of the connecting pipe 12 and in the inner space 16 between the liner 4 and the casing 2.

The pumping of oil by pump 1 along the tubing string 3 at the wellhead from the upper perforation holes 20 of the formation continues until the water cone rises to the upper perforation holes 20. The density of the liquid in the inner space 16 and the space 17 of the channel 6 increases, the flow of water from lower perforations 21 into the inner space 19 of the connecting tube 12.

At the same time, oil flows from the space 17 into the inner space 16 of the channel 6 and water is pumped out, which enters the inner space 19 of the connecting pipe 12 to receive a pump 2, which pumps water through the tubing string 1 at the wellhead. Then the cycle repeats.

In the process of developing a formation 6 with bottom water, the level of WOC 9 changes (rises or falls), therefore, to increase the efficiency of the device in order to avoid mixing oil and water at the pump intake, the volumes of oil and water are regulated. An increase in the volume of water withdrawal indicates an increase in the level of KSS 9, and conversely, a decrease in the volume of water withdrawal indicates a decrease in the level of KSS 9.

In order to reduce the volume of withdrawn water and increase the volume of oil withdrawal, i.e. to reduce the level of KSS 9, it is necessary to raise the connecting tube 12. For this, the plunger 23 of the pump 1 with the rod string 24 (see FIG. 1) is removed from the pipe string 3 and using any known device, for example, using a catcher 25, any known construction, deflated in the pipe string 3 (see FIG. 3) on the rope 26, the connecting tube 12 is internally gripped (see FIG. 3) and axially moved upward, for example, by 2.5 m. The snap ring 13 (see FIG. 2 and 3) fixes the connecting tube 12 relative to the shank 4 in the upper position. Next, the trap 25 is released from the grip with the connecting tube 12 and the trap 25 with the rope 26 is removed from the pipe string 3. The plunger 23 of the pump 1 with the rod string 24 is lowered into the pipe string 3 (see FIG. 1) and pump 1 is started, while the cycles of the device are repeated as described above. As a result, the volume of withdrawn water begins to decrease and the selection of the volume of oil increases, while the level of KSS 9 decreases.

In order to increase the volume of water withdrawn and reduce the volume of oil extraction, it is necessary to lower the connecting tube 12. To do this, remove the plunger 23 of the pump 1 from the pipe string 3 with the rod string 24 (see Fig. 1) and using any known device, for example, with a load ( 1, 2, 3. not shown), consisting of two or three pipes, the outer diameter of which is greater than the diameter of the connecting tube 12 by 5-10 mm lowered into the pipe string 3 (see Fig. 3), unload the cargo to the funnel 25 of the connecting pipe 12. As a result, the connecting pipe 12 is lowered into from example 2 m (1, 2, 3 are not shown). The retaining ring 13 (see figure 1 and 2) fixes the connecting tube 12 relative to the shank 4 in the lower position (figure 1, 2, 3 is not shown).

Next, the load with the rope is removed from the pipe string 3. The plunger 23 of the pump 1 with the rod string 24 (see FIG. 1) is lowered into the pipe string 3 and the pump 1 is started up, while the operation cycles of the device are repeated as described above.

As a result, the volume of withdrawn water begins to increase, and the selection of the volume of oil decreases, while the level of KSS 9 increases.

The proposed device allows you to adjust the water cone in the well by changing the levels of water and oil withdrawal depending on the level of water-oil contact, which increases its efficiency.

Also, the proposed device due to the regulation of the volumes of water and oil withdrawal allows to prevent their mixing during the ascent along the pipe string and to obtain products on the well surface that do not require subsequent separation into separate phases, and also reduces the likelihood of the formation of oil-water emulsions and deposition of paraffin from for the rapid transition from water withdrawal to oil withdrawal.

Claims (1)

A device for regulating a water cone in a well, comprising a pump lowered into the casing of the well on a pipe string with a liner bottom connected to the connecting pipe, as well as two supply channels located in the well, one channel for supplying oil and the other channel for water supply, with the possibility of entering the well from the reservoir, the channel entrances are located at different levels, and the outputs are directed to the pump intake, characterized in that the pipe string shank is provided externally with a packer installed in the casing string not a well at the level of oil-water contact, and radial holes above the packer, moreover, in the liner below the radial holes, a hollow plug is rigidly mounted, into which a connecting pipe is sealed with axial movement and fixing, and the connecting pipe is fixed relative to the shank using a split retaining ring round cross-section installed in the inner groove of the hollow plug and fixing the connecting tube in semicircular notches made on the bunk the surface of the connecting pipe, wherein the channel for supplying oil is formed by the inner space of the casing above the packer, the radial holes of the liner and the space between the liner and the connecting pipe, and the channel for supplying water is formed by the internal space of the casing below the packer and the internal space of the connecting pipe, both channels are located opposite the perforations in the aquifer and oil parts of the reservoir, and the outputs are directed to the pump intake.

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