CN112096939B - Two-stage safety valve with pressure real-time monitoring function for fracturing pipeline - Google Patents

Abstract

The invention discloses a two-stage safety valve with pressure real-time monitoring function for a fracturing pipeline, which comprises a pressure regulating hand wheel, a gland, a needle valve spring, an upper shell, a needle valve core, a middle shell, a spring base sleeve, a spring base, a valve rod, a valve core seat, a lower shell and the like. The pressure regulating hand wheel, the pressure cap and the upper shell are sequentially connected through threads, and a gland, a needle valve spring and a needle valve core are sequentially arranged at the lower end of the pressure regulating hand wheel; the valve rod is in threaded connection with the spring base and is arranged in the valve core seat, the lower end of the spring base sleeve is provided with the valve core seat, the upper end of the spring base sleeve is connected with the middle shell, and the spring is arranged between the spring base and the upper shell; the upper shell, the middle shell, the valve rod, the valve core seat and the lower shell are internally provided with pressure relief channels; if the pipeline pressure exceeds the allowable value, the needle valve core is opened first, the liquid pressure difference causes the valve rod to move along the axis, and the pressure relief hole of the valve rod is communicated with the inner cavity of the pressure relief opening, so that rapid pressure relief is realized. The invention avoids frequent start and stop of the fracturing pump and ensures that the pressure of the pipeline does not exceed the allowable pressure value.

Description

A double-stage safety valve for fracturing pipeline with real-time pressure monitoring

Technical Field

The invention relates to an oilfield fracturing pipeline safety tool, in particular to a double-stage safety valve for a fracturing pipeline with real-time pressure monitoring.

Background Art

During oilfield fracturing operations, the fracturing fluid is delivered to the wellbore through the plunger pump on the fracturing truck. However, various faults may occur during the fracturing process, such as: the packer does not release, the sandblaster is blocked, the fracturing string is stuck, sand is blocked, the oil pipe is blocked, etc., which leads to abnormal increase in pipeline pressure.

The existing measures to avoid excessive pressure include: installing a spring-loaded safety valve, an auxiliary safety valve, and a supplementary load safety valve at the outlet of the plunger pump on the fracturing truck; installing a pressure sensor on the fracturing pipeline to monitor the pressure of the pipeline in real time. When the pipeline pressure is higher than the preset allowable pressure value, the plunger pump of the fracturing truck is controlled to stop working. The main function of the first measure is to protect the plunger pump, so the allowable pressure value is much higher than the allowable pressure of the pipeline and downhole fracturing tools, and it cannot effectively protect the pipeline, downhole tools, etc., and the spring-loaded safety valve is large in size and has low pressure regulation accuracy, and the power-assisted safety valve and the supplementary load safety valve have complex structures and high manufacturing costs. In the second measure, the frequent start and stop of the plunger pump will cause the motor to heat up and shorten the service life of the motor components; in addition, at the moment the plunger pump is started, the moving parts will produce a large acceleration from static to moving, and the resulting external force will cause damage to the main components such as the pump shaft, piston, crankshaft and connecting rod.

Therefore, it is necessary to invent a safety valve for fracturing pipelines with real-time pressure monitoring, which can adjust and monitor the pipeline pressure without stopping the operation of the fracturing vehicle plunger pump to ensure the safe operation of the fracturing equipment.

Summary of the invention

The present invention overcomes the shortcomings of existing overpressure protection devices for fracturing pipelines and provides a double-stage safety valve for fracturing pipelines with real-time pressure monitoring, thereby realizing monitoring and regulation of pipeline pressure and ensuring safe operation of the fracturing pipeline.

In order to achieve the above object, the present invention adopts the following technical scheme:

A double-stage safety valve for a fracturing pipeline with real-time pressure monitoring comprises a pressure regulating hand wheel, a pressure cap, a retaining ring, a pressure cover, a needle valve spring, an upper shell, a needle valve core, screws, a first O-type sealing ring, an intermediate shell, a pressure gauge, a spring, a spring base sleeve, a spring base, a valve stem, a valve core seat, a second O-type sealing ring, a third O-type sealing ring, a lower shell and a pressure relief interface.

The two ends of the lower shell are connected to the fracturing pipe by threads; the left side of the pressure relief interface is connected to the pressure relief pipe, the right side of the pressure relief interface is connected to the side of the middle shell by welding, and the lower shell is connected to the middle shell by welding.

The valve stem and the spring base are connected by threads to form a valve core and are installed in the valve core seat; the spring base sleeve is connected to the intermediate housing by threads, one end of the spring is installed in the annular groove of the spring base, and the other end of the spring is connected to the bottom surface of the upper housing; the valve stem is provided with an axial through hole connected to the well repair fluid channel of the lower housing, a middle chamber is formed between the upper housing and the intermediate housing, a pressure measuring hole is provided on the side wall of the intermediate housing, the axial through hole is connected to the middle chamber and the pressure measuring hole, and a pressure gauge is installed on the right side of the pressure measuring hole; when the pressure of the well repair fluid in the fracturing pipe is lower than the preset allowable pressure value, the well repair fluid in the fracturing pipe flows into the middle chamber through the axial through hole in the valve stem, and flows to the measuring end of the pressure gauge through the pressure measuring hole, thereby measuring and displaying the pressure of the well repair fluid in the fracturing pipe in real time.

The upper shell and the middle shell are connected by screws, the pressure regulating hand wheel and the pressure cap are connected by threads, the pressure cap is connected to the upper shell by threads, the retaining ring is installed between the pressure cap and the upper shell, the lower end of the pressure regulating hand wheel is in contact with the pressure cover, the pressure cover is installed in the middle of the upper shell, the needle valve spring is installed at the lower end of the pressure cover, the lower end of the needle valve spring is connected to the needle valve core, the conical surface of the needle valve core is in line contact with the end surface of the upper shell, the pressure regulating hand wheel is rotated to drive the pressure cover to move along the axial direction, the preload force of the needle valve spring is changed, and the allowable pressure value of the pipeline is adjusted.

A left side hole is provided on the left side of the upper shell body, an upper side hole connecting the left side hole and the middle chamber is provided on the bottom of the upper shell body, a middle pressure relief hole is provided on the left side of the intermediate shell body, the interior of the pressure relief interface is a pressure relief port inner cavity, and the axial through hole, the upper side hole, the left side hole, the middle pressure relief hole, and the pressure relief port inner cavity constitute a small amount of pressure relief channels; a vertical, through first radial hole, a second radial hole, and an axial through hole are provided on the valve stem, a third radial hole is provided on the valve core seat, an annular channel is formed between the lower part of the valve core seat and the intermediate shell body, and the axial through hole, the first radial hole, the second radial hole, the third radial hole, the annular channel and the pressure relief port inner cavity constitute a quick pressure relief channel.

When the pressure of the fracturing pipeline exceeds the preset allowable pressure value, the pressure of the workover fluid acts on the conical surface of the needle valve core through the axial through hole, the middle chamber and the upper side hole. Under the combined force of the needle valve spring and the fluid pressure acting on the conical surface of the needle valve core, the needle valve core moves upward along the axis, the needle valve core opens, the left hole is connected with the upper side hole, and the fluid flows into the inner cavity of the pressure relief port through the axial through hole, the middle chamber, the upper side hole, the left hole and the middle pressure relief hole to achieve a small amount of pressure relief; at this time, the flow of the fluid causes a local head loss at the axial through hole, and the local head loss causes the workover fluid pressure in the middle chamber to be lower than the workover fluid pressure in the workover fluid channel. Under the combined force of the fluid pressure difference and the spring, the valve stem moves upward along the axis to achieve rapid pressure relief.

Four needle valve springs are arranged at equal intervals between the gland and the needle valve core in the circumferential direction, and four needle valve springs are arranged in the axial direction. The stiffness and free length of each needle valve spring are the same. Rotating the pressure regulating hand wheel can drive the gland to move in the axial direction, so as to accurately adjust the preset opening pressure value of the needle valve core. The parallel use of the needle valve springs effectively reduces the volume of the safety valve.

Compared with the prior art, the present invention has the following beneficial technical effects:

(1) When the fracturing of the fracturing pipeline exceeds the preset allowable pressure value, the needle valve will release the pressure first, causing the pressure in the corresponding chamber on the upper part of the valve stem to decrease. Under the action of the liquid pressure difference, the valve stem moves upward along the axis, and the pressure relief hole on the valve stem is connected to the pressure relief interface. The pipeline is quickly depressurized, thereby avoiding frequent start and stop of the pump, ensuring that the pressure of the fracturing pipeline does not exceed the allowable pressure value, and maintaining the safe operation of the pipeline.

(2) By rotating the pressure regulating hand wheel to change the compression amount of the needle valve spring and observing the pressure value on the pressure gauge, the allowable pressure value of the pipeline can be set. The setting of the allowable pressure value is convenient, simple and accurate. During operation, the pressure gauge displays the pressure value of the pipeline, which is convenient for accurate and real-time control of the pipeline pressure.

(3) Five needle valve springs with the same stiffness and free length are installed in parallel between the gland and the needle valve core, which is conducive to accurately adjusting the allowable pressure value of the needle valve; the parallel installation of the needle valve springs is conducive to reducing the volume and manufacturing cost of the safety valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the appearance of the present invention;

Fig. 2 is a schematic diagram of the A-A section of Fig. 1;

Fig. 3 is a schematic diagram of the B-B section of Fig. 2;

FIG4 is a schematic diagram of the needle valve pressure relief of the present invention;

FIG. 5 is a schematic diagram of rapid pressure relief of the present invention.

In the figure: 1, pressure regulating hand wheel, 2, pressure cap, 3, retaining ring, 4, pressure cover, 5, needle valve spring, 6, upper shell, 7, needle valve core, 8, screw, 9, first O-ring, 10, intermediate shell, 11, pressure gauge, 12, spring, 13, spring base sleeve, 14, spring base, 15, valve stem, 16, valve core seat, 17, second O-ring, 18, third O-ring, 19, lower shell, 20, pressure relief interface, 21, axial through hole, 22, workover fluid channel, 23, middle chamber, 24, pressure measuring hole, 25, left hole, 26, upper side hole, 27, middle pressure relief hole, 28, pressure relief port cavity, 29, first radial hole, 30, third radial hole, 31, second radial hole, 32, annular channel.

DETAILED DESCRIPTION

The present invention is further described in detail below in conjunction with the accompanying drawings:

As shown in Figures 1, 2 and 3, a double-stage safety valve for a fracturing pipeline with real-time pressure monitoring includes: a pressure regulating handwheel 1, a pressure cap 2, a retaining ring 3, a pressure cover 4, a needle valve spring 5, an upper shell 6, a needle valve core 7, a screw 8, a first O-ring 9, an intermediate shell 10, a pressure gauge 11, a spring 12, a spring base sleeve 13, a spring base 14, a valve stem 15, a valve core seat 16, a second O-ring 17, a third O-ring 18, a lower shell 19 and a pressure relief interface 20.

As shown in FIG. 1 , during operation, both ends of the lower shell 19 are connected to the fracturing pipe through threads, and the left side of the pressure relief interface 20 is connected to the pressure relief pipe.

As shown in FIG. 2 and FIG. 3 , the pressure regulating hand wheel 1 is rotated to drive the pressure cover 4 to move downward along the axis. The downward movement of the pressure cover 4 along the axis changes the length of the needle valve spring 5 to complete the setting of the allowable pressure value.

As shown in FIGS. 2 and 3 , when the pressure of the workover fluid in the fracturing pipe is lower than the preset allowable pressure value, the workover fluid in the fracturing pipe flows into the middle chamber 23 through the axial through hole 21 in the valve stem 15, and flows to the measuring end of the pressure gauge 11 through the pressure measuring hole 24, thereby measuring and displaying the pressure of the workover fluid in the fracturing pipe in real time.

As shown in FIG. 4 , the arrows in the figure represent the flow direction of the workover fluid in the pressure relief channel during pressure relief. When the pressure of the workover fluid in the fracturing pipe is higher than the preset allowable pressure value, the pressure of the workover fluid acts on the conical surface of the needle valve core 7 through the axial through hole 21, the middle chamber 23, and the upper side hole 26. Under the combined force of the needle valve spring 5 and the fluid pressure acting on the conical surface of the needle valve core 7, the needle valve core 7 moves upward along the axis, and the left side hole 25 is connected with the upper side hole 26. The fluid flows into the pressure relief port cavity 28 through the axial through hole 21, the middle chamber 23, the upper side hole 26, the left side hole 25, and the middle pressure relief hole 27 to achieve a small amount of pressure relief.

As shown in Figures 4 and 5, the arrows in the figures represent the flow direction of the workover fluid in the pressure relief channel during pressure relief. When the pressure of the workover fluid in the fracturing pipe is higher than the preset allowable pressure value, the needle valve core 7 moves upward along the axis, and the left hole 25 is connected with the upper hole 26 to form a fluid channel. The workover fluid flows through the axial through hole 21 to generate a local head loss, resulting in the workover fluid pressure in the middle chamber 23 being lower than the workover fluid pressure in the workover fluid channel 22. Under the combined effect of the workover fluid pressure difference and the spring 12, the valve stem 15 moves upward along the axis, and the first radial hole 29 and the second radial hole 31 on the valve stem 15 are connected with the third radial hole 30 on the valve core seat 16, the annular channel 32 and the pressure relief port inner cavity 28 of the pressure relief interface 20, thereby achieving rapid pressure relief.

Claims (1)

1. The double-stage safety valve for the fracturing pipeline with the pressure real-time monitoring function is characterized by comprising a pressure regulating hand wheel (1), a pressure cap (2), a baffle ring (3), a gland (4), a needle valve spring (5), an upper shell (6), a needle valve core (7), a screw (8), a first O-shaped sealing ring (9), a middle shell (10), a pressure gauge (11), a spring (12), a spring base sleeve (13), a spring base (14), a valve rod (15), a valve core seat (16), a second O-shaped sealing ring (17), a third O-shaped sealing ring (18), a lower shell (19) and a pressure relief interface (20);

Two ends of the lower shell (19) are connected with the fracturing pipeline through threads; the left side of the pressure relief interface (20) is connected with a pressure relief pipeline, the right side of the pressure relief interface (20) is connected to the side surface of the middle shell (10) through welding, and the lower shell (19) is connected with the middle shell (10) through welding;

The valve rod (15) and the spring base (14) are connected through threads to form a valve core, and the valve core is arranged in the valve core seat (16); the spring base sleeve (13) is connected with the middle shell (10) through threads, one end of the spring (12) is arranged in the annular groove of the spring base (14), and the other end of the spring (12) is connected with the bottom surface of the upper shell (6); the valve rod (15) is provided with an axial through hole (21) communicated with a workover fluid channel (22) of the lower shell (19), a middle cavity (23) is formed between the upper shell (6) and the middle shell (10), a pressure measuring hole (24) is formed in the side wall of the middle shell (10), the axial through hole (21) is communicated with the middle cavity (23) and the pressure measuring hole (24), and a pressure gauge (11) is arranged on the right side of the pressure measuring hole (24) so as to realize real-time display of pressure of a fracturing pipeline;

The upper shell (6) is connected with the middle shell (10) through a screw (8), the pressure regulating hand wheel (1) is connected with the pressure cap (2) through threads, the pressure cap (2) is connected with the upper shell (6) through threads, the baffle ring (3) is installed between the pressure cap (2) and the upper shell (6), the lower end of the pressure regulating hand wheel (1) is contacted with the gland (4), the gland (4) is installed in the middle of the upper shell (6), the needle valve spring (5) is installed at the lower end of the gland (4), the needle valve core (7) is installed at the lower end of the needle valve spring (5), the conical surface of the needle valve core (7) is in line contact with the end surface of the upper shell (6), the pressure regulating hand wheel (1) is rotated to drive the gland (4) to move along the axis direction, the pretightening force of the needle valve spring (5) is changed, and therefore the allowable pressure value of a pipeline is regulated; 4 needle valve springs (5) are arranged between the gland (4) and the needle valve core (7) at equal intervals along the circumferential direction, the rigidity and the free length of each needle valve spring (5) are the same, and the gland (4) is driven to move along the axial direction by rotating the pressure regulating hand wheel (1), so that the preset opening pressure value of the needle valve core (7) is accurately regulated, and the parallel use of the needle valve springs (5) effectively reduces the volume of the two-stage safety valve for the fracturing pipeline with the pressure real-time monitoring;

The valve rod (15) is provided with a vertical and penetrating axial through hole (21), a first radial hole (29) and a second radial hole (31), the valve core seat (16) is provided with a third radial hole (30), a circumferential channel (32) is formed between the lower part of the valve core seat (16) and the middle shell (10), and the axial through hole (21), the first radial hole (29), the second radial hole (31), the third radial hole (30), the circumferential channel (32) and a pressure relief port inner cavity (28) of the pressure relief interface (20) form a rapid pressure relief channel so as to realize rapid pressure relief;

The left side of the upper shell (6) is provided with a left hole (25), the bottom of the upper shell (6) is provided with an upper hole (26) which is communicated with the left hole (25) and the middle cavity (23), the left side of the middle shell (10) is provided with a middle pressure relief hole (27), the pressure relief interface (20) is internally provided with a pressure relief hole inner cavity (28), and the axial through hole (21), the upper hole (26), the left hole (25), the middle pressure relief hole (27) and the pressure relief hole inner cavity (28) form a pressure relief channel; when the pipeline pressure exceeds a preset allowable pressure value, under the resultant force action of the liquid pressure and the needle valve spring (5) in the middle chamber (23) of the middle shell (10), the needle valve core (7) is opened, fluid flows into the pressure relief port inner cavity (28) of the pressure relief interface (20) through the axial through hole (21), the upper side hole (26), the left side hole (25) and the middle pressure relief hole (27), the well workover hydraulic pressure in the middle chamber (23) is lower than the well workover hydraulic pressure in the well workover fluid channel (22) due to the local head loss of the fluid, the valve rod (15) moves upwards along the axis under the resultant force action of the fluid pressure difference and the spring (12), and the first radial hole (29), the second radial hole (31) on the valve rod (15) are communicated with the third radial hole (30), the annular channel (32) and the pressure relief port inner cavity (28) of the pressure relief interface (20) on the valve core seat (16), so that quick pressure relief is realized.