RU2780756C1 - Check valve for electric submersible pumps for high-rate wells - Google Patents

Abstract

FIELD: valves.

SUBSTANCE: non-return valve is designed as an accessory device in the installation of an electric centrifugal pump for the production of products from wells, mainly with large production capabilities (≥500 m³/day). The check valve is equipped with top and bottom subs, and in the top sub a shaped sleeve is installed with the possibility of replacement for a fixed grip of the ball-valve, and in the lower sub with the possibility of replacement there is a seat made of abrasive-resistant material with a wide passage opening, the lower end of the shaped sleeve facing into side of the saddle, equipped with at least four toothed modules to ensure unimpeded entry and exit of the ball-valve into the internal cavity of the figured cup, as well as to keep it from self-oscillations in the figured cup, and the ball-valve is made of abrasion-resistant ceramic material. In the upper part of the figured cup there are lateral through radial channels, at least three, at an angle α=30°…45° to the axis of rotation of the figured cup. Above the landing seat on the lower sub, a conical chamfer is made at an angle β=30°…45° to the axis of rotation of the check valve body.

EFFECT: invention is aimed at reducing high-speed flows in the internal cavity of the valve, eliminating zones of flow turbulence, expanding the cross-sectional area of hydraulic passages, protecting the shut-off element from direct abrasive action of the pumped product.

2 cl, 5 dwg

Description

The non-return valve of electric submersible pumps (OK) units refers to oil engineering products and is intended as an accessory device for an electric submersible pump (ESP) for the production of well products (gas-liquid mixture) mainly from high-rate wells (≥500 m ³ /day).

In the last decade, to stimulate the inflow from wells, they are drilled with a horizontal end of the wells, and multi-stage hydraulic fracturing of the productive formation is also carried out. The operation of these wells requires the use of downhole equipment of increased operational reliability for all components of this equipment, including electric submersible pumps (ESP), submersible electric motor (SEM) and check valve (OK), included in the downhole equipment. The non-return valve must perform a number of important functions: to maintain working condition during pressure testing of tubing and compressor pipes (tubing pipes) lowered into the well; prevent the discharge of well products from the tubing during ESP shutdowns; facilitate repeated or periodic start-up of the ESP; eliminate the effect of "turbine" rotation of the shaft of the electric centrifugal pump.

When using well-known and mastered by oil engineering OK, their use in wells equipped with ESPs is associated with their frequent failures, which are caused by erosion of seals and constrictions in through channels by high-speed flows of pumped products and loss of sealing ability. The composition of the liquid pumped out of the well (formation fluids) contains mechanical impurities that accelerate the process of abrasive erosion of seals. This is especially evident during the operation of ESPs in high-rate wells (≥500 m ³ /day). In this regard, the technical task of creating OK for high-rate wells equipped with ESPs with an increased uptime is relevant and subject to consideration, taking into account the developed innovative technical and technological solutions.

When conducting patent studies of well-known technical solutions for OK, numerous valve solutions have been identified that are developed, described in the technical literature and used in various industries where, according to the technical conditions of work, automatic prevention of backflows of process liquids and gases in various hydraulic systems is required. As shut-off elements in OK in the oil industry, poppet, petal and ball are known, which require an appropriate analysis and their technical evaluation.

Known check valve installation electric centrifugal pump (utility model patent No. 152084 IPC F16K 15/00) [1], poppet type. With the simplicity of the design, the poppet version of the check valve cannot be used for a long time in high-rate wells with ESP, due to the influence of the large frontal resistance of the poppet-valve and the intense manifestation of abrasive erosion of the poppet and the internal cavity of the valve.

Known check valve (patent for invention No. 2544930 IPC E21V 34/06) [2], which is made with the possibility of flushing the cavity of the electric centrifugal pump from solid precipitation. It has a shut-off device in the form of a poppet valve. This technical solution does not exclude the accelerated development of erosion processes of the sealing elements of the check valve in conditions of high content of mechanical impurities (≥1 g/l) and well flow rates (≥500 m ³ /day).

Known check valve ESP (patent for invention No. 2187709 IPC F04D 15/02) [3]. This OK is recommended for installation in the upper section of the electric centrifugal pump (ESP) in its head module. When oil is produced with a high content of associated gas (gas-liquid mixture), such a technical solution leads to complications at the stage of starting the ESP into operation, since the closed check valve located in the immediate vicinity of the ESP impellers leads to gas accumulation in the cavity of the ESP working sections , which prevents its regular start-up after forced shutdowns.

The closest solution in terms of technical essence was a non-return valve for ESPs (patent for the invention RU No. 2379566 IPC F16K 15/04) [4], taken as a prototype, including a body, a seat, a valve cage, a shut-off element-ball installed in a restrictor with conical holes, turning into conical holes to increase the through hole.

The disadvantage of the check valve according to the identified patent is intense abrasive wear (erosion), both of the shut-off element-ball located in the immediate vicinity of the seat and insufficient diameter of the passage hole, and the channels limited in terms of the area of the active section for passing the fluid pumped out of the well in the valve cage. The service life of the well-known OK, when operating in high-rate wells with a high content of mechanical impurities (≥1 g/l), is significantly reduced and does not suit oilmen, taking into account modern technical requirements.

In this regard, the objective of the proposed technical solution is to increase the service life of the check valve with ESP in high-yield wells (≥500 m ³ /day), in the conditions of pumping out well products (gas-liquid mixture), with a content of mechanical impurities (≥1 g/l).

The goal is achieved by design and technological methods, using technical solutions of the inventive step.

The check valve of installations of electric submersible pumps for high-rate wells, includes a cylindrical body with connecting threads and a seat with a ball valve placed in it, while the check valve is equipped with top and bottom subs, in the top sub, coaxially with the body of the check valve, it is installed, with the possibility replacement, a shaped cup, for a fixed grip of the ball-valve, and in the lower sub, with the possibility of replacement, there is a seat made of abrasive-resistant material, with a wide through hole, while the lower end of the shaped cup, facing the saddle, is equipped with at least at least four toothed modules to ensure unhindered entry and exit of the ball-valve into the internal cavity of the figured cup, as well as to keep it from self-oscillations in the figured cup, and the ball-valve is made of abrasive-resistant ceramic material, side through radial channels are made in the upper part of the figured cup , not less than three, at an angle α=30°...45° to the axis of rotation of the shaped cup, and, above the seat on the lower sub, a conical chamfer is made at an angle β=30°...45° to the axis of rotation of the check valve body. The gear modules are made with a uniform pitch, and the height of the tooth h is made from the ratio h=(0.5...0.8)⋅D ₁ , where D ₁ is the ball-valve diameter.

Check valve installations of electric centrifugal pumps for high-rate wells according to the present technical solution is shown in the figures (Fig. 1-5):

in fig. 1 shows a diagram of a check valve for an ultrasonic pump in the initial state;

in fig. 2 shows a cross section of a check valve in the area of the radial channels;

in fig. 3 shows a diagram of the reverse laying in the operating mode of the ESP;

in fig. 4 shows a diagram of a figured glass;

in fig. 5 shows a section of the shaped cup in the section of the gear module.

The check valve of installations of electric centrifugal pumps for high-rate wells (Fig. 1 ... 5) includes: a cylindrical body 1, equipped with an upper 2 and a lower 3 connecting subs, which are equipped, respectively, with threads P _3> P ₄ , on the inner surface of the sub 3 a chamfer is made under angle β=30°...45° (Fig. 3), caused by the need to reduce the coefficient of local hydraulic resistance, and reduce the turbulence of the flow of the pumped gas-liquid mixture, confirmed by studies [6] (Appendix 3). In the upper sub 2, coaxially with the valve body, a shaped cup 4 is installed, with the possibility of replacement (for example, using a threaded connection), to cover and accommodate the ball-valve 5 when the ESP is running. In the lower sub 3, with the possibility of replacement, seat 6 made of abrasive-resistant material, for example, steel 95X18, with a wide through hole with a diameter (dc) that ensures tight contact with the ball-valve 5. Radial channels 7 are made on the shaped cup 4, at an angle β=30°...45°, contributing to a decrease in the coefficient of local hydraulic resistance and erosion in the radial channels during the movement of the products pumped out by the well (gas-liquid mixture).

The lower end 9 of the figured cup 4, facing the saddle 6, is equipped with gear modules 10 (at least four), made with a uniform step S, and a height h=(0.5...0.8)⋅D ₁ (view A in Fig. 5). To prevent abrasive wear and self-oscillations of the ball-valve 5 in the figured cup 4, it is fixed on the chamfer 7. The outer diameter (Dн) of the check valve is made equal to the outer diameter of the electric centrifugal pump, which is the main component of the ESP unit. The fulfillment of this condition is necessary for the unhindered descent into the well of the ESP assembly, which is equipped with a cable line laid and fixed with clamps from the upper head of the submersible electric motor (SEM) to the wellhead fitting along the outer surface of the ESP and tubing (not shown in Fig.).

The inner diameter (Dv, Fig. 2) of the body 1 of the check valve is made taking into account the compliance with the strength characteristics of the body of the body, ensuring equal strength of the OK design at all stages of operation of the ESP.

For example, a production well with an inner diameter of the production string (EC) of 148.3 mm and a potential flow rate of 500 m ³ /day must be equipped with UETsNM6-800. The outer diameter of the ESP according to TU 26-06-1485-96 is 114 mm in diameter. Therefore, the optimal outer diameter (Dн) OK should be equal to 114 mm. And the inner diameter D in the body 1 OK, after carrying out strength calculations (not given), can be made with a diameter of 98 mm. For the selected example of the configuration of the ESP with OK, we use a ball of silicon nitride (Si3N4) with a diameter (D ₁ ) of 60 mm, which provides an optimal distribution of areal channels for the passage of the gas-liquid mixture pumped out of the well in the internal cavity of the OK housing. And the diameter of the inlet (dc) is taken, for example, from the ratio: dc=Sin60°⋅D ₁ ; or, for our example, dc=0.866⋅60≈52 mm.

To raise the ball-valve 5 to the upper position, it is necessary that the product of the midsection (Mssh) of the ball-claran 5, associated with its diameter D ₁ , and the pressure drop ΔР (Fig. 3) be greater than the mass of the ball-valve 5. If Mssh= π/4⋅(D ₁ ) ² , and the volume of the ball-valve V ₁ =4/3⋅π⋅(D ₁ /2) ³ , then Мсш⋅ΔР≥V ₁ ⋅ρ; in this case ΔР≥V ₁ ⋅ρ/Мсш,

where: ρ is the density of the ball-valve material, (for silicon nitride ρ=3.21 g/cm ³ ;

For example: D ₁ -60 mm = 6 cm; Let's determine the required pressure drop (support for the ball) ΔР; To do this, we determine the volume of the ball V ₁ =4/3⋅3.1415⋅(6/2) ³ =113.1 cm ³ ; Ball mass М ₁ =113.1⋅3.21=363 g. Midsection Mssh=3.1415/4⋅6 ² = ^28.27 cm2. Then the required pressure drop ΔР must be at least ΔР=363/28.27=12.84 g/cm ² = 0.0128 kg/cm ² = 1259 Pa ≥ 0.001259 MPa.

To estimate the size of 4 radial channels, for example, a square section in a figured glass and create the required pressure drop ΔР, we use the approximate formula (7.4) from [5]. She is recorded as

where: Q - fluid flow rate, l/s; μ=0.9 - nozzle (channel) flow rate; f - cross-sectional area of the nozzles (channels), cm ² ; ΔP - pressure drop, 10 MPa.

Если принять отбор жидкости из скважины в объеме Q=500 м³/сутки=5,8 л/с и подставив известные значения, определим общую площадь (foб) для четырех радиадьных каналов, получим

Определим площадь f квадратного сечения для одного радиального канала. Для этого поделим foб на 4. В итоге получим f=40,7/4=10,17 см² со стороной квадрата равного 3,2 см. Следовательно, для подъема шара-клапана 5 необходимо обеспечить размер четырех каналов, площадь каждого из них должна быть около 10 см², что конструктивно, для принятого типоразмера, вполне допустимо.For our case, from the above formula

If we accept the withdrawal of fluid from the well in the volume Q=500 m ³ /day=5.8 l/s and substituting the known values, we determine the total area (fob) for four radial channels, we get

Let us determine the area f of the square section for one radial channel. To do this, we divide fob by 4. As a result, we get f = 40.7 / 4 = 10.17 cm ² with a side of the square equal to 3.2 cm. Therefore, to lift the ball valve 5, it is necessary to ensure the size of four channels, the area of each should be about 10 cm ² , which is constructively, for the accepted standard size, quite acceptable.

Check valve installations of electric centrifugal pumps for high-rate wells works as follows.

Work with the check valve begins with its inclusion in the layout of the ESP as part of the lowered tubing by screwing on threaded connections P ₁ and P ₂ (Fig. 1) with tubing (not shown in Fig.). In the process of lowering the ESP on the tubing into the well, according to the regulations in force in the oil industry, they perform periodic pressure testing of the tubing, during which they identify tubing that does not meet the tightness requirements of the tubing and produce their rejection.

When the ESP is not operating, the ball-valve 5 occupies the lowest position (Fig. 1) providing sealing contact with the seat 6. This condition is met even in those cases when the wellbore at the installation interval of the OK will have a horizontal position. In this case, the ball-valve 4 will close the hole in the seat 6 with hydrostatic pressure (overflow) in the cavity of the tubing located above the OK, and will be ready to perform all the functions assigned to it.

When the ESP is running, the ball-valve 5, due to the movement of the liquid and the existing pressure drop ΔР (Fig. 3), caused by local hydraulic resistance in the radial channels 7, occupies the uppermost position, abutting against the conical chamfer 8, which is provided in the internal cavity of the figured glass 4. In this case, the movement of the pumped liquid (for understanding the process) is shown by streamlines (a).

The above calculations confirm the possibility of implementing this technological solution in terms of the fact that the ball-valve 5, in the OK, when the ESP is running, will rise in the cavity of the figured cup 4 and will take a stationary state leaning on the chamfer 8, which excludes its wear in the gas-liquid mixture flow.

The technical result is associated with the achievement of a time-multiple increase in the service life of OK by design and technological methods, using new technical solutions aimed at: reducing high-speed flows in the internal cavity of the valve; elimination of zones of turbulence in the flow of pumped out gas-liquid (mixture) well production; expansion of the cross-sectional area of the through hydraulic channels; protection of the locking element - the ball from direct abrasive action of the pumped products; use of abrasive resistant materials.

The proposed and described technical solutions in the OK, aimed at increasing the service life of the check valve in the layout of downhole equipment with ESP for high-rate wells, have the signs of novelty given in the description, significant distinguishing features that allow performing the task, and its design has the necessary simplicity, providing the possibility of mastering the production and application in the oil industry.

Information sources:

1. Utility model patent No. 152084 IPC F16K 15/00.

2. Patent for invention RU No. 2544930 IPC E21V 34/06. Check valve of an electric centrifugal installation and a method for cleaning the filter at the pump intake. BI No. 8 2015.

3. Patent for invention RU No. 2187709 IPC F04D 15/02 F04D 15/02. Check valve of the borehole electric centrifugal pump. BI No. 23 2000.

4. Patent for invention RU No. 2379566 IPC F16K 15/04. Check Valve. BI №2 2010.

5. Grozdev B.P. Exploitation of gas and gas condensate fields: Reference manual. - M.: Nedra, 1988. 575 p.

6. Altshul A.D. hydraulic resistance. M: Nedra 1982.

Explanations for drawings:

1 - valve body;

2 - top sub;

3 - lower sub;

4 - figured glass;

5 - ball valve;

6 - valve seat;

7 - radial channel;

8 - landing chamfer;

9 - lower end of the figured glass;

10 - tooth crown module;

a - streamlines of gas-liquid production of the well;

Dn - outer diameter of the check valve;

Dv - internal diameter of the check valve;

D ₁ - ball-valve diameter;

dc - ball valve seat diameter;

R ₁ , R ₂ - connecting threads of the sub with tubing;

R ₃ , R ₄ - connecting threads of the OK body with subs;

ΔР - pressure drop across the ball-valve when the ESP is running;

h - linear size along the height of the crown module tooth;

S is the dimensional step of the teeth of the crown module;

α is the angle of inclination of the inlets of the windows of the radial channels;

β - angle of inclination of the end surface of the connecting sub.

Claims (3)

1. Check valve for installations of electric submersible pumps for high-rate wells, including a cylindrical body with connecting threads and a landing seat with a ball-valve placed in it, characterized in that the check valve is equipped with top and bottom subs, and in the top sub coaxially with the check valve body is installed with the possibility of replacing a shaped sleeve for a fixed grip of the ball-valve, and in the lower sub with the possibility of replacement, a seat made of abrasive-resistant material with a wide passage hole is installed, the lower end of the shaped sleeve, facing the side of the seat, is equipped with at least four gear modules to provide the possibility unobstructed entry and exit of the ball-valve into the internal cavity of the figured cup, as well as keeping it from self-oscillations in the figured cup, and the ball-valve is made of abrasive-resistant ceramic material, while in the upper part of the figured cup there are side through radii at least three channels, at an angle α=30°...45° to the axis of rotation of the shaped sleeve, and above the seat on the lower sub, a conical chamfer is made at an angle β=30°...45° to the axis of rotation of the check valve body. 2. Check valve according to claim 1, characterized in that the gear modules are made with a uniform pitch, and the tooth height h is made from the ratio h=(0.5...0.8)⋅D ₁ , where D ₁ is the diameter of the ball valve.

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