RU2421602C1 - Procedure for well operation - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: procedure consists in lowering production string, electro-centrifugal pump with inlet module and electric engine with hydraulic protection into well, in supply of withdrawn production to wellhead, and in successive flushing internal cavities of electric centrifugal pump plant from presence of pyrobitumen, paraffin, and mechanical impurities of carried-over rock. The well is operated under a non-stop mode. A universal valve with functions of back and flush valves is preliminary set to pressure parameters specified for this well: Popen - pressure of valve opening for a flush mode. Pexc. - pressure of flush fluid pressurisation. The universal valve operates as a back valve during withdrawal of oil. Supply of pumped production to the wellhead is carried out till the moment of electric engine power rise, whereupon the electric engine is shutdown. Flush fluid is charged with the pump unit for pressurisation of working substances at flush operations in oil and gas wells; the universal valve operates as a flush one. Operation of the valve unit is repeated. ^ EFFECT: raised efficiency of pump equipment operation in production well. ^ 5 cl, 4 dwg

Description

The invention relates to the oil industry, in particular to the field of well operation, and can be used to eliminate asphalt-resin-paraffin, hydrate and ice plugs in the pipe space of wells equipped with an electric centrifugal pump (ESP).

One of the most pressing problems in the oil industry during oil production is the deposition of paraffin deposits on the inner surfaces of the walls of tubing along which the oil flows, and the formation of a plug from impurities in the upper parts of the pump working bodies due to settling of mechanical impurities and other solid particles, which leads to a steady decrease in well productivity and a sharp increase in the dynamic level, sometimes up to the wellhead, and increased wear, leading to premature exit at the failure of ESP, and sometimes to plant fall to the bottom hole wells.

It is possible to increase the efficiency of electric centrifugal pumps in these conditions by removing already formed sediments in a working installation, improving the layout of the installation by using special devices to increase the stability of its operation in the well.

Known methods of operating wells in which various methods and devices are used to remove hydrate-paraffin plugs in tubing (tubing): steaming the plugs with hot steam or water through tubes or hoses lowered into the tubing; exposure to corks with various chemicals that produce heat and break chemical bonds in paraffin; heating plugs with different types of heaters lowered into the tubing - electric, electrolytic, chemical, etc. (see, for example, Khoroshilov V.A., Malyshev A.G. Prevention and elimination of hydrate deposits during oil production. M: VNIIOENG, 1986 (Overview of the oil industry. Oilfield business. Issue 15/122).

A known method of operating oil and gas wells, which consists in maintaining the temperature of oilfield equipment, for example tubing, is higher than the temperature of the paraffin deposits due to compressed gas injected into the well, while the temperature is maintained above the temperature of the paraffin and hydrate deposits due to the internal energy of the gas that is injected into the well in a closed cycle without preheating it and at a temperature above the inversion temperatures of the Joule-Thomson effect, while lzuyut helium which is throttled in the borehole. (Russian Patent No. 2158361, IPC ЕВВ 43/24, published October 27, 2000)

A well-known method of operating a well, including the descent of a lifting string into the well, installing a plug-in deep pump in it on the support seat, subsequent flushing of the well with a hot agent and pumping oil, the lifting string is equipped with a flushing column, the shoe of which is placed at the level of the oil reservoir, and before landing of the insert pump into the support seat, the well is flushed with a hot agent to the depth of the columns lowered by the lifting and flushing columns, after which the pump is lowered into the support seat and put into operation. (Russian Patent No. 20144440, IPC Е21В 43/00, published on June 15, 1994)

A disadvantage of the known methods is the need for additional devices and insufficient washing of downhole equipment.

The objective of the invention is to increase the efficiency of pumping equipment in production wells by reducing downtime and ensuring uninterrupted operation of the well.

This problem is solved due to the fact that in the method of operating the well, including the descent into the well of a string of tubing connected to a valve containing a valve block with a shut-off element in the form of a ball, an electric centrifugal pump with an input module, an electric motor with hydraulic protection, and the supply of a pumped product at the wellhead, subsequent flushing of the internal cavities of the installation of the electric centrifugal pump from the presence of asphaltenes, paraffins, and mechanical impurities of the rocks, well operation is carried out stvlyaetsya continuous operation, versatile valve that performs the inverse function, and the flushing valve, pre-set to a certain pressure for a given borehole parameters:

Rotkr. - valve opening pressure for flushing mode.

R huts - discharge pressure of the flushing fluid,

the tubing string is lowered into the well when the universal valve is closed, which at the same time acts as a non-return valve, protecting the electric centrifugal pump-motor system from the pressure of the liquid column in the pipeline route; at the end of the tubing string descent, the electric motor is pumped, the pumped product under operating pressure it is supplied from the pump from below to the universal valve, the locking element in the form of a ball rises to its highest position, the cavity is located I above the valve block, connects to the cavity below the valve block, the pumped product is thrown into the cavity of the tubing and through them goes to the wellhead, while the pumped product is delivered to the wellhead until the electric motor increases, after which the electric motor is stopped while the universal valve acts as a non-return valve, protecting the system from the pressure of the column of the pumped product in the pipeline route, then by the discharge unit I working fluids during washing operations in oil and gas wells, for example, the CA-320 aggregate starts pumping up washing liquid, the universal valve works as a washing liquid, the valve device will be repeated until the internal cavities of the installation of the electric centrifugal pump and downhole equipment are completely washed, then the electric motor is started , the pumped-out product is thrown into the cavity of the tubing and through them enters the wellhead.

In addition, the washing of the internal cavities of the installation of the electric centrifugal pump is carried out in a pulsed micro-shock cyclic mode by forcing the flushing fluid into the tubing string. In addition, the washing of the internal cavities of the installation of the electric centrifugal pump is carried out through the annulus.

Additionally, during the descent, to prevent spontaneous opening of the valve, the calculated amount of liquid, for example produced water, is poured into the tubing string into the tubing string, which presses the valve shutter in the form of a ball to the seat.

Additionally, the weight of the liquid column is not less than 1.2 reservoir pressure.

The invention is illustrated by drawings.

Figure 1 - oil, oil and gas well with downhole equipment;

Figure 2 is a longitudinal section of the valve backwash in stop mode;

Figure 3 is a longitudinal section of a backwash valve in operating mode;

Figure 4 is a longitudinal section of a backwash valve in flushing mode.

Installation of an electric centrifugal pump (ESP) includes an electric motor 1 with hydraulic protection 2, designed to protect the internal cavity of the electric motor from ingress of formation fluid, as well as compensating for temperature changes in oil volumes and its flow rate, an electric centrifugal pump 3 with an input module 4, at the output of pump 3 at a predetermined interval a universal valve 5 is installed in the well, which acts as a check and flush valve, connected to the tubing string 6. For flushing the pump, a unit for pumping bochih liquid during the flushing works on oil and gas wells, such as CA-320 unit with the plunger or piston pump (not shown).

The length of the pump is determined by the number of working stages, the number of which, in turn, is determined by the main parameters of the pump - flow and pressure. The feed and pressure of the steps depend on the cross section and design of the flow part (blades), as well as on the speed. The universal valve 5 comprises a hollow cylindrical body 7, in which, with the possibility of sliding along its vertical axis, a valve block 8 is installed, preloaded by a spring 9, pre-compressed by force, the value of which is determined by the working pressure, i.e. the pressure of a liquid column in a vertical pipeline.

A groove 10 is made in the inner through hole of the valve block 8 for locating the locking element in the form of a metal ball 11, which restricts its vertical movement, the lower end of the groove 10 being the seat 12 for the ball 11. In the valve block 8 there are made radial through evenly located holes 13 made so that when the ball 11 is in its highest position, the cavity located above the valve block 8 and the cavity located below the valve block are connected. In the lower part of the hollow cylindrical body 7, the control stop 14 is fixedly fixed with a pressure end 15 in its upper part, made in the form of a hollow stepped glass, in the wall of which there are made radial uniformly located through holes 16.

A universal valve 5, containing a valve block 8 with a locking element in the form of a metal ball 11, a seat 12 and a spring 9 with a control stop 14, is an effective mechanism for flushing downhole equipment with reverse current through the tubing, using the valve you can check the tightness of the tubing.

Universal valve 5 is pre-configured for pressure parameters defined for a given well:

Rotkr. - valve opening pressure for flushing mode;

R huts - discharge pressure of the flushing fluid.

The method of operating the well is as follows.

Well operation is carried out in a continuous mode, in which the tubing string 6 together with a universal valve 5, pre-configured for pressure parameters defined for a given well:

Rotkr. - valve opening pressure for flushing mode;

R huts - discharge pressure of the flushing fluid,

an electric centrifugal pump 3 with an input module 4, an electric motor 1 with a hydraulic protection 2 is lowered into the well, while the universal valve 5 is in the closed position, and to prevent its spontaneous opening inside the column, the calculated amount of liquid, for example produced water, which presses the ball 11 against the saddle, is poured 12, while the weight of the liquid column must be at least 1.2 reservoir pressure.

In this case, the universal valve 5 acts as a non-return valve, protecting the system of the electric centrifugal pump-motor from the pressure of the liquid column in the pipeline route. In this case, the cavity located above the valve block 8 and the cavity located below the valve block 8 are disconnected, and a guaranteed clearance is maintained between the pressure end 15 and the lower point of the ball 11, the spring 9 is pre-compressed.

Then the electric motor is started. 1, the pumped-out product under working pressure is supplied from the pump 3 from below to the universal valve 5, passes through the radial evenly located through holes 16 located in the wall of the stop 14, the ball 11 rises to its highest position, the pumped-out product passes through the radial through evenly spaced openings 13, and the cavity located above the valve block is connected to the cavity located below the valve block, the pumped product is discharged into the cavity of the pump of tubing 6, and through them arrives at the wellhead.

Depending on the physicochemical composition of the oil and the properties of the formation itself and on the well’s operating conditions, the internal cavities of the ESP are gradually overgrown by the presence of asphaltenes, paraffins, mechanical impurities of the rocks and other solid inclusions with the formation of plugs with self-deposition both in the tubing and on the working bodies pump. The pump in this case begins to wedge, while the power increases, performance drops. In this case, the electric motor is stopped, the universal valve 5 holds the column of fluid in the tubing to the mouth and does not allow the fluid to go into the reservoir.

In this case, the ball 11 under the influence of its own weight is lowered, closes the hole of the seat 12 and the universal valve 5 acts as a check valve, protecting the system from the column pressure of the pumped product in the pipeline route. Using valve 5, the tightness of the tubing 6 is checked.

Then, the aggregate for pumping working fluids during washing operations in oil and gas wells, for example, the CA-320 aggregate, begins to pump the washing liquid in a pulsed-microshock cyclic mode by reverse current through the tubing 6. Once the pressure has reached P open. the valve block 8 is shifted downward by the amount of the gap K, overcoming the force of the spring 9, and the ball 11 comes into contact with the pressure face 15 of the stop 14, the valve block 8 continues to move down and the seat 12 of the valve 5 is detached from the ball 11, forming an annular gap into which under high pressure P h. - pressure of the flushing fluid injection, flushing fluid rushes impulse supplied by the plunger (piston) pump of the unit. The resulting buoyancy force from liquid pressure, acting on the lower surface of the metal ball 11, raises it up and increases the space for the passage of the washing liquid, which, passing through the radial through evenly spaced holes 13 and the radial evenly spaced through holes 16 of the stop 14 down towards the pressure port pump, directly into the cavity of the pump 3, cleaning it.

The pressure in tubing 6 drops. At this point, the spring 9 begins to rise up with the valve block 8, and the ball 11, under its own weight and pressure of the liquid column, begins to sink down into the seat 12, while the passage for the flushing fluid current sharply decreases, and as soon as the ball 11 touches the seat 12, the pressure in tubing 6 rises sharply to the opening value and the valve block 8 begins to lower again. At the moment of supplying the next portion of the flushing fluid from the plunger (piston) pump, the pressure increases spasmodically, the ball 11 rises sharply, increasing the passage sections for the flushing pass. And the cycle described above will be repeated. Thus, the operation of the valve device will be repeated until the internal cavities of the installation of the electric centrifugal pump and downhole equipment are completely washed.

Considering the fact that the flushing fluid from the unit is supplied by a plunger (piston pump), thereby pulse-increasing the flushing pressure in the tubing 6, the valve block 8 thereby enhances the flushing fluid supply pulse due to the design features, resulting in pulsed micro-shock cyclic effects of the fluid flow on the internal cavities and working bodies of the ESP, they restore the efficiency of the ESP. Thus, the washing of the internal cavities of the installation of the electric centrifugal pump is carried out in a pulsed-microprobe cyclic mode.

The advantages of this washing method:

1. It is not necessary to install additional equipment in the well before flushing.

2. Significantly reduced the amount of flushing fluid to restore the operability of downhole equipment.

3. Reduces well downtime for flushing.

4. The flushing fluid does not contact the casing, which increases the survivability of the well.

5. The equipment is flushed efficiently and with high quality.

6. Excludes additional tripping operations. This method allows to significantly reduce the flushing time, the amount of flushing fluid, thereby increasing the economic effect of the well.

It is possible to flush the internal cavities of the installation of the electric centrifugal pump through the annulus, while the flushing fluid is fed from above into the annulus, through the inlet module 4 of the pump 3 it enters the universal backwash valve 5, passes through the radial evenly located through holes 16 located in the stop wall 14 , the ball 11 rises to its highest position, the flushing fluid passes through the radial through evenly spaced holes 13, and the cavity located above the valve block is connected to the cavity located below the valve block, flushing fluid is discharged into the cavity of the tubing 6 and through them to the surface. The valve device operation will be repeated until the downhole equipment is completely flushed, then an electric motor is started, the pumped product is thrown into the cavity of the tubing 6 and through it enters the wellhead.

Claims (5)

1. The method of operating the well, including the descent into the well of a string of tubing connected to a valve containing a valve block with a shut-off element in the form of a ball, an electric centrifugal pump with an input module, an electric motor with hydroprotection, pumping the pumped product to the wellhead, and then flushing the internal cavities of the installation of an electric centrifugal pump from the presence of asphaltenes, paraffins, mechanical impurities of the rocks, characterized in that the well is operated continuously implicit mode, versatile valve that performs the inverse function, and the flushing valve, pre-set to a certain pressure for a given borehole parameters:
Rotkr. - valve opening pressure for flushing mode.
R huts - discharge pressure of the flushing fluid,
the tubing string is lowered into the well when the universal valve is closed, which at the same time acts as a non-return valve, protecting the electric centrifugal pump-motor system from the pressure of the liquid column in the pipeline route; at the end of the tubing string descent, the electric motor is started, the pumped product under operating pressure it is supplied from the pump from below to the universal valve, the locking element in the form of a ball rises to its highest position, the cavity is located above the valve block, it connects to the cavity located below the valve block, the pumped product is thrown into the cavity of the tubing and through it goes to the wellhead, while the pumped product is fed to the wellhead until the electric motor increases, after which the electric motor is stopped, at the same time, the universal valve acts as a non-return valve, protecting the system from the pressure of the column of the pumped product in the pipeline route, then by the discharge unit when flushing work in oil and gas wells, for example, with the CA-320 unit, the flushing fluid begins to be pumped, the universal valve acts as a flushing fluid, the valve device will be repeated until the internal cavities of the installation of the electric centrifugal pump and downhole equipment are completely flushed, then the electric motor is started, the pumped product is thrown into the cavity of the tubing and through them enters the wellhead. 2. The method of operating the well according to claim 1, characterized in that the flushing of the internal cavities of the installation of the electric centrifugal pump is carried out in a pulsed-micropulse cyclic mode by pumping the flushing fluid with reverse current into the tubing string. 3. The method of operating the well according to claim 1, characterized in that the washing of the internal cavities of the installation of the electric centrifugal pump is carried out through the annulus. 4. The method of operating a well according to claim 1, characterized in that, during descent, to prevent spontaneous opening of the valve, a calculated amount of liquid, for example produced water, is poured into the tubing string, which presses the valve shutter in the form of a ball to the seat. 5. The method of operating the well according to claim 4, characterized in that the weight of the liquid column is not less than 1.2 reservoir pressure.

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