RU2235904C1 - Method of operation of well pumps with automatically maintaining preset dynamic level of pumping out liquid medium in well (versions) - Google Patents

Abstract

FIELD: oil and gas producing industry.

SUBSTANCE: according to proposed method, oil-well submersible pump is installed on tubing string in well in zone of formation, and liquid medium is pumped out of well. When assembling and lowering tubing string into well, two chambers are installed on tubing string one over the other, higher than submersible pump. After lowering tubing string into well and before pumping liquid medium from formation, pumped out liquid medium dynamic level controller made in form of valve is installed in lower well chamber. Annulus pressure relative to tubing string space pressure regulator is installed in upper well chamber. Said regulator is made in form of valve. Pumping out of liquid medium, for instance, oil, is carried out with annulus closed from side of wellhead. Operating pressure of regulator and controller is set to provide pressure in tubing string space, in place of mounting of dynamic level controller at moment of its opening, higher than pressure in annulus in the same point, but not lower than minimum tolerable pressure according to operating conditions in well bottom. Pressure in tubing string space at moment of opening of pressure regulator should be lower than annulus pressure in the same point. According to other version, submersible pump is mounted on tubing string in well in zone of formation, and liquid medium is pumped out of well. When assembling and lowering tubing string into well, chamber is installed on tubing string higher than submersible pump, and after lowering tubing string into well and before pumping out liquid medium from well formation, liquid medium dynamic level controller made in form of valve is installed in well chamber. Wellhead is connected to annulus pressure relative to tubing string pressure regulator made in form of valve to discharge excess pressure from well annulus into pumped out liquid medium collecting system. Then pumping out of liquid medium, for instance, oil is carried out. Operating pressure of regulator and controller is set to provide pressure in tubing string space in point of mounting of dynamic level controller at moment of its opening higher than annulus pressure in the same point, but not lower than minimum tolerable pressure according to operating conditions in well bottom. Pressure in pumped out liquid medium collecting system at moment of opening of pressure regulator should be lower than pressure in well annulus in point of installation of pressure regulator in wellhead. Thanks to it automatic maintenance of preset dynamic level of pumped out liquid medium in well is provided.

EFFECT: increased life between overhauls.

3 cl, 2 dwg

Description

A method of operating borehole pumps with automatic maintenance in the well of a given dynamic level of the pumped liquid medium (options).

The invention relates to the oil and gas industry and can be used for oil production.

Known methods of operating wells with submersible pumping units, where sucker-rod pumping units or a borehole centrifugal electric pump installation are used to lift a fluid (Sh.K. Gimatudinov, RS Andriasov, IT Mishchenko, and others. “Oil production reference book”. -M., Nedra, 1983, p. 132-199; 244-246)

When oil is pumped, it is lowered into the well on a tubing string (tubing) and driven by a string of pump rods in the case of using a rod rig or electric power supplied by cable from the earth's surface, in the case of using a borehole centrifugal electric pump.

The closest to the invention in technical essence and the achieved result is a method of operating a well pump described in a “device for lifting carbonated liquid from a well”, which consists in installing a well submersible pump on a string of tubing in a well in a formation zone and by the latter produce pumping from a well of a liquid medium (USSR patent No. 1825544, class F 04 F 5/54, 1988).

The disadvantage of this method is that, in the case when the productivity of the well pump exceeds the volume of reservoir fluid entering the well, this leads to a drop in the dynamic level associated with the level of the pressure fluid at the pump intake and shutdown, resulting in a low overhaul period and the associated high costs of routine well repair and loss of oil production due to downtime.

The problem to which the present invention is directed is to automatically maintain a given dynamic level of the pumped liquid medium in a pump well and, as a result, increase the overhaul period of its operation.

This problem is solved due to the fact that the method of operating borehole pumps with automatic maintenance in the well of a given dynamic level of the pumped liquid medium consists in installing a borehole submersible pump on the string of tubing in the well in the formation zone and pumping out of the well by means of the latter liquid medium, while the layout and descent into the well of the string of tubing on the last above the submersible pump set one above the other two borehole the chamber, and after the pipe string is lowered into the well before pumping out the liquid produced from the formation from the well in the lower well chamber, a valve regulator of the dynamic level of the liquid medium pumped out of the well is installed in the lower well chamber, and a pressure regulator made in the form of a valve is installed in the upper well chamber annulus in relation to the tubing string, pumping liquid medium, such as oil, from the well, with annulus closed to the mouth of the well, etc. and this, the response pressure of the regulators is set so that at the time the dynamic level regulator opens, the pressure in the cavity of the tubing at its installation point is higher than the pressure in the annulus of the well at the same point, but not lower than the minimum face pressure wells, and the pressure in the cavity of the tubing at the time of opening the pressure regulator is lower than the pressure in the annulus of the well at the same point.

In another embodiment, the above problem is solved due to the fact that the method of operating well pumps with automatic maintenance in the well of a given dynamic level of the pumped liquid medium consists in installing a well submersible pump on the string of tubing in the well in the formation zone and using the latter liquid is pumped out from the well, while when arranging and lowering the tubing string into the well, the wells are installed on the last above the submersible pump the chamber, and after the pipe string is lowered into the well, before pumping the liquid medium extracted from the formation into the well, the valve regulates the dynamic level of the liquid medium pumped from the well into the well chamber, and the wellhead is connected to the annular pressure regulator with respect to the tubing string, the space of the well with the possibility of relieving excess pressure from the annulus of the well into the collection network of the liquid medium pumped from the well, then pumping out a liquid medium, for example oil, from the well, while the response pressure of the regulators is set so that at the time the dynamic level regulator opens, the pressure in the cavity of the tubing at its installation point is higher than the pressure in the annulus of the well at the same point, but not lower than the minimum permissible pressure at the bottom of the well under operating conditions, and the pressure in the collection network of the liquid medium pumped out of the well at the time of opening the pressure regulator is lower than the pressure in ubnom space of the well at the wellhead installation on the pressure regulator in the annulus.

As the studies showed, by transferring a portion of the fluid pumped out of the well and maintaining a predetermined pressure in the annulus of the well, it is possible to achieve stable operation of the well pumps, especially in the case of an unstable flow of the pumped fluid from the formation.

In the case of use as pressure and dynamic level control valves that have a compressed gas chamber with a charging unit to set the desired design pressure, the operating conditions can be determined as follows.

The operating conditions of the dynamic level controller and the charging pressure are selected based on the following expression:

R _zar. = P _open1. = P _mp1. × R + P _prot. × (1-R),

where R _zar. - charging pressure of the bellows chamber of the dynamic level controller, kg / m ² ;

P _{open 1.} - opening pressure of the dynamic level controller, kg / m ² ;

P _tr1. - pressure in the tubing at the installation point of the dynamic level controller, kg / m;

R _t. - pressure in the annulus of the well at the installation point of the dynamic level controller, kg / m ² ;

R is the ratio of the passage area of the saddle to the effective area of the bellows chamber of the dynamic level controller.

The installation depth of the dynamic level controller is selected based on the condition that at the time of its discovery the inequality P _{Tr1 is observed.} > P _zat. .

The operating conditions of the pressure regulator in the annulus and the opening pressure are selected based on the following expression:

R _{open 2.} = P _Tr2. + R _rd. ,

where P _open2. - opening pressure of the pressure regulator in the annulus, kg / m ² ;

P _tr2. - pressure in the tubing at the installation point of the pressure regulator in the annulus, kg / m ² ;

_Rd. - pressure difference due to the pressure difference in the annulus, borehole and tubing at the installation point of the pressure regulator, kg / m ² .

In this case, the condition P _zat. > P _tr2. at the time of opening the pressure regulator.

Between themselves, the opening pressures of the dynamic level regulator and the pressure regulator in the annular space are connected by the following relationship:

P _open1 > P _open2 + ρ g (H ₁ -H _2din. ),

where P _open1 - opening pressure of the stabilizer of the dynamic level, kg / m;

R _open2 - opening pressure of the pressure regulator, kg / m ² ;

H ₁ - the height of the liquid column at the installation site of the dynamic level controller, m;

H ₂ - the height of the liquid column at the installation site of the regulator in the annulus, m;

ρ g (H ₁ -N _2din. ), is the pressure of the liquid column in the annulus of the well above the dynamic level regulator, where ρ is the density of the liquid, kg / m ³ , g is the acceleration of gravity, m / s ² .

The same function will be performed if a pressure regulator is installed in the annulus at the wellhead.

Figure 1 presents a diagram of a well pump installation for implementing the described method of operating well pumps with automatic maintenance of a given dynamic level of a pumped liquid medium with two chambers on a tubing string; figure 2 is a diagram of a plant with a pressure regulator in the annulus installed at the wellhead.

A downhole pump installation contains:

1 - production casing;

2 - tubing string (tubing);

3 - a borehole chamber with a pressure regulator in the annulus of the well;

4 - downhole chamber with a regulator of the dynamic level of the pumped liquid medium;

5 - downhole submersible pump;

6 - pressure regulator in the annulus installed at the wellhead.

The method is implemented as follows:

After the descent of the borehole submersible pump 5 on the tubing string 2 with the borehole chambers 3; 4 into the production casing 1 of the well, it is put into operation to pump out the kill fluid. After the selection of the kill fluid in its entirety and its utilization, using a cable technique, a pressure regulator in the annulus of the well and a dynamic level regulator are installed in the borehole chambers 3 and 4, respectively.

The annular space of the well is closed from the side of the wellhead and the well submersible pump 5 is put into operation. In the first period of operation, when the flow of fluid from the reservoir and the nominal productivity of the borehole submersible pump are not agreed, i.e. its productivity is higher than the influx from the reservoir, the dynamic level of the fluid in the well begins to decline and when it reaches a critical point, the dynamic level regulator in the borehole chamber 4 opens and part of the fluid from the tubing string 2 flows into the annulus of the well, compensating for the decrease in the dynamic level of the pumped liquid environment and even ensuring its growth. When the growth of the dynamic level reaches the calculated value and provides the specified pressure at the installation point of the dynamic level controller, it closes and, accordingly, the flow of the pumped liquid medium from the tubing string to the annulus ceases.

If necessary, the cycle automatically repeats.

The pressure regulator in the annulus of the borehole in the borehole chamber 3 prevents the flowing of the pumped liquid medium through the annulus of the well caused by the high gas content in the pumped liquid medium as a result of the gas separator of the borehole submersible pump 5. Since the well is operated with a closed annulus, the pressure regulator 3 for certain conditions relieves excess pressure from the annular annular space of the well into the tubing string 2.

The pressure regulator in the annular space of the well 3 can be used for additional injection of fluid into the tubing string 2 in the case when the supply characteristic of the formation is higher than the productivity of the well submersible pump 5 and the dynamic level of the liquid rises above the installation site of the pressure regulator 3.

The same function will be performed if a pressure regulator is installed in the annulus 6 at the wellhead in accordance with the second embodiment of the method of operating well pumps.

Thus, the claimed method is more efficient and economical compared to the method of the prototype and provides a smoother, softer conclusion to the optimal mode of operation of a well submersible pump in the initial period of its operation and ensures its stable operation, automatically maintaining a given dynamic level of the pumped liquid medium, which leads to a longer overhaul period of the well submersible pump and, as a rule, to a more complete development of reserves from the bottomhole zone of the well.

Claims (2)

1. The method of operation of borehole pumps with automatic maintenance in the well of a given dynamic level of the pumped liquid medium, which consists in the fact that a borehole submersible pump is installed on the string of tubing in the well in the formation zone, and by means of the latter, the liquid medium is pumped out of the well, characterized in that when arranging and lowering into the well the tubing string, two borehole chambers are installed one above the other on the last above the submersible pump, and after the descent before the start of pumping from the well, the liquid medium extracted from the formation in the lower borehole chamber, a valve regulator of the dynamic level of the liquid medium pumped out of the borehole is installed in the form of a valve, and a pressure regulator in the annulus relative to the casing made in the form of a valve tubing space, pumping a liquid medium, such as oil, from a well, with an annular space closed from the wellhead, with a response pressure The regulators are set so that at the moment the dynamic level regulator opens, the pressure in the cavity of the tubing at the point of its installation is higher than the pressure in the annulus of the well at the same point, but not lower than the minimum allowable pressure at the bottom of the well, and the pressure in the cavity of the tubing at the time of opening the pressure regulator is lower than the pressure in the annulus of the well at the same point. 2. The method of operation of borehole pumps with automatic maintenance in the well of a given dynamic level of the pumped liquid medium, which consists in installing a borehole submersible pump on the string of tubing in the well in the formation zone and, by means of the latter, pumping out the liquid medium from the well, characterized in that when arranging and lowering the tubing string into the well, the borehole chamber is installed on the last above the submersible pump, and after lowering the tubing string into the wells Before pumping out the liquid medium extracted from the formation in the well, a valve-shaped regulator of the dynamic level of the liquid medium pumped out of the well is installed in the well chamber, and the wellhead is connected to a pressure regulator made in the form of a valve in the annular space of the well with respect to the tubing string with the possibility of relieving excess pressure from the annulus of the well into the collection network of the liquid medium pumped from the well, then pumping the liquid medium from the well s, for example, oil, while the response pressure of the regulators is set so that at the time the dynamic level regulator opens, the pressure in the cavity of the tubing at its installation point is higher than the pressure in the annulus of the well at the same point, but not lower than the minimum operating conditions of pressure at the bottom of the well, and the pressure in the collection network of the fluid pumped out of the well at the time of opening the pressure regulator is lower than the pressure in the annulus of the well at the installation point wellhead pressure regulator annulus.

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