Gas well anti-freezing and plugging production device and control method thereof

Abstract

The present application relates to oilfield exploitation technology field, it is a kind of gas well anti-freezing and blocking production device and control method, the former includes valve body, driving mechanism, ultrasonic generator and control module, closed valve cavity is equipped in valve body, the left side of valve body is equipped with the import of right end and the left part of valve cavity intercommunication, the lower side of valve body is equipped with the export of upper end and the lower part of valve cavity intercommunication, the upper side of valve body is equipped with the installation channel of lower end and the upper part of valve cavity intercommunication corresponding export position, valve rod is sealingly installed in installation channel.The present application is reasonable and compact, when using, import is communicated with gas well export, when natural gas hydrate is generated in valve cavity, make ultrasonic generator emit ultrasonic wave to valve cavity by control module, use the energy and vibration effect of ultrasonic wave to destroy and dissociate natural gas hydrate structure, to convert it into natural gas and water, hydrate can be avoided to block pipeline and equipment in the process of natural gas exploitation and transportation, improve production efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of oilfield development technology, specifically to a gas well antifreeze and anti-blockage production device and its control method. Background Technology

[0002] In cold climates, especially in low-temperature environments (<5℃), when the wellhead production pressure is higher than the hydrate formation pressure, the wellhead tree process is prone to freezing and blockage. Freezing and blockage can damage the tree valves, gas pipelines, and wellhead monitoring equipment, seriously affecting the normal production and operation of the gas well. Traditional control methods have strong limitations, and traditional manual operation methods often cannot monitor and adjust the wellhead pressure in a timely and accurate manner, making it difficult to effectively prevent and deal with freezing and blockage problems.

[0003] The main technologies and devices currently used are: (1) Temperature and pressure monitoring: using sensors and monitoring devices to monitor the temperature and pressure changes in the gas well in real time to help analyze and judge the risk of freezing and blockage; (2) Heating device and control system: by installing heating device and intelligent control system, the temperature inside the gas well is controlled to prevent freezing and blockage; (3) Valve and pipeline design: special materials and structures are used to strengthen the cold resistance of valves and pipelines to reduce the risk of freezing and blockage.

[0004] In light of the current requirements for natural gas collection, the existing anti-freezing production measures have the following problems: (1) Judging the risk of freezing solely from temperature and pressure monitoring and adjusting the production system has limited effect and cannot guarantee the gas production of the gas well, which will affect the normal production and drainage of the gas well and cause the risk of liquid accumulation in the wellbore; (2) Heating methods have problems such as complex equipment, difficult construction, large investment and high energy consumption. Some well sites have not yet been equipped with power grids. The gas well site is limited and relies on solar power supply, so its adaptability is obviously insufficient; (3) The design of valves and pipelines cannot completely solve the freezing problem. Although they have a certain mitigating effect, they require modification of wellhead equipment or pipelines, which also has problems of poor feasibility and economy. Summary of the Invention

[0005] This invention provides a gas well antifreeze production device and its control method, which overcomes the shortcomings of the prior art and can effectively solve the problems of complex equipment, difficult construction and high energy consumption in the existing gas well antifreeze production devices.

[0006] One of the technical solutions of this invention is achieved through the following measures: a gas well anti-freezing and anti-blocking production device, comprising a valve body, a drive mechanism, an ultrasonic generator, and a control module. The valve body has a closed valve cavity. The left side of the valve body has an inlet whose right end communicates with the left part of the valve cavity. The lower side of the valve body has an outlet whose upper end communicates with the lower part of the valve cavity. The upper side of the valve body corresponding to the outlet position has an installation channel whose lower end communicates with the upper part of the valve cavity. A valve stem is sealed and installed in the installation channel. A valve core that can close the outlet when moved downward and open the outlet when moved upward is fixedly installed at the lower end of the valve stem. A connecting bracket is fixedly installed on the upper side of the valve body. A drive mechanism that enables the valve stem to move up and down is fixedly installed on the upper side of the connecting bracket. The right side of the valve body corresponding to the inlet position has a transmitting hole whose left end communicates with the valve cavity. An ultrasonic generator is sealed and installed in the transmitting hole. The ultrasonic generator and the drive mechanism are both electrically connected to the control module.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: An inlet flange can be fixedly installed on the left side of the valve body corresponding to the inlet position. The outer side of the inlet flange is provided with a first mounting hole that connects the inside and outside. A pressure sensor is sealed and installed in the first mounting hole. An outlet flange is fixedly installed on the lower side of the valve body corresponding to the outlet position. The outer side of the outlet flange is provided with a second mounting hole that connects the inside and outside. A temperature and pressure sensor is sealed and installed in the second mounting hole. Both the pressure sensor and the temperature and pressure sensor are connected to the control module.

[0008] The aforementioned ultrasonic generator can be an ultrasonic probe.

[0009] A valve seat can be fixedly installed on the upper part of the above-mentioned outlet. The valve seat has a tapered throttling orifice that runs vertically through the center and is wider at the top and narrower at the bottom. The outer side of the valve core matches the inner wall of the throttling orifice.

[0010] A filter sleeve fitted on the outside of the valve stem can be fixedly installed on the upper end of the valve seat. The filter sleeve has several filter holes that are connected inside and outside at intervals on its outer side.

[0011] The second technical solution of the present invention is achieved through the following measures: a control method for a gas well antifreeze production device, comprising the following steps: S1 connects the inlet flange to the gas well outlet; S2, obtains the inlet pressure, outlet temperature and outlet pressure respectively based on the pressure sensor and the temperature and pressure sensor; S3. Based on the natural gas hydrate formation model, establish judgment conditions. When the production conditions meet the judgment conditions, start the ultrasonic generator. S4. When the outlet pressure and inlet pressure are the same, turn off the ultrasonic generator and the gas well enters the continuous production stage. Repeat steps S2 and S3.

[0012] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The determination conditions in step S3 above are: the outlet temperature is less than or equal to the temperature warning threshold and the inlet pressure is greater than or equal to the pressure warning threshold.

[0013] This invention features a reasonable and compact structure. In use, the inlet is connected to the gas well outlet. When natural gas hydrates are generated within the valve chamber, the control module causes an ultrasonic generator to emit ultrasonic waves into the valve chamber. The energy and vibration of the ultrasonic waves are used to break down and dissociate the natural gas hydrate structure, thereby converting it into natural gas and water. Specifically, the ultrasonic waves emitted by the generator produce high-frequency mechanical vibrations. These vibrations propagate through the medium, including the natural gas hydrates and surrounding natural gas, water, or other media. When the ultrasonic waves reach the surface of the natural gas hydrate particles, energy is transferred to the particles, causing them to vibrate slightly. The ultrasonic waves propagate at extremely high frequencies; millions of vibrations per second can generate significant internal pressure changes in the hydrate particles. Due to these pressure changes, the hydrate structure is disrupted, and the gas and water in the hydrate molecules separate. After ultrasonic treatment, the gas in the natural gas hydrate is released, while the water remains in a liquid state. Through this process, ultrasonic waves can effectively eliminate natural gas hydrates, preventing hydrate blockage of pipelines and equipment during natural gas extraction and transportation, thus improving production efficiency and safety. Attached Figure Description

[0014] Appendix Figure 1 These are schematic diagrams of the main sectional view of Examples 1 to 5.

[0015] Appendix Figure 2 This is a schematic diagram of the circuit structure for Example 1.

[0016] The codes in the attached diagram are as follows: 1 is valve body, 2 is drive mechanism, 3 is valve chamber, 4 is inlet, 5 is outlet, 6 is valve stem, 7 is valve core, 8 is connecting bracket, 9 is throttling orifice, 10 is emission orifice, 11 is ultrasonic generator, 12 is inlet flange, 13 is outlet flange, 14 is temperature and pressure sensor, 15 is valve seat, 16 is filter sleeve, 17 is filter hole, and 18 is pressure sensor. Detailed Implementation

[0017] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0018] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0019] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1, as shown in the appendix Figure 1 , 2 As shown, the gas well antifreeze production device includes a valve body 1, a drive mechanism 2, an ultrasonic generator 11, and a control module. The valve body 1 has a closed valve chamber 3 inside. The left side of the valve body 1 has an inlet 4 whose right end communicates with the left part of the valve chamber 3. The lower side of the valve body 1 has an outlet 5 whose upper end communicates with the lower part of the valve chamber 3. The upper side of the valve body 1 corresponding to the outlet 5 has an installation channel whose lower end communicates with the upper part of the valve chamber 3. A valve stem 6 is sealed and installed in the installation channel. A valve core 7 is fixedly installed at the lower end of the valve stem 6, which can close the outlet 5 when moved downward and open the outlet 5 when moved upward. A connecting bracket 8 is fixedly installed on the upper side of the valve body 1. A drive mechanism 2 that can move the valve stem 6 up and down is fixedly installed on the upper side of the connecting bracket 8. The right side of the valve body 1 corresponding to the inlet 4 has a transmitting hole 10 whose left end communicates with the valve chamber 3. An ultrasonic generator 11 is sealed and installed in the transmitting hole 10. The ultrasonic generator 11 and the drive mechanism 2 are both electrically connected to the control module.

[0020] Depending on the requirements, the drive mechanism 2 is a known existing technology, such as a worm gear reducer motor or an electric actuator (linear stroke), and the control module is a known microcontroller. In use, inlet 4 is connected to gas well outlet 5. When natural gas hydrate is generated in valve chamber 3, the control module causes ultrasonic generator 11 to emit ultrasonic waves into valve chamber 3. The energy and vibration of the ultrasonic waves are used to destroy and dissociate the structure of natural gas hydrate, thereby converting it into natural gas and water. Specifically, the ultrasonic waves emitted by ultrasonic generator 11 generate high-frequency mechanical vibrations. The ultrasonic waves propagate in the medium in the form of mechanical vibrations. When the ultrasonic waves propagate to the surface of natural gas hydrate particles, the energy is transferred to the particles and causes them to vibrate slightly. The ultrasonic waves propagate at extremely high frequencies, and the millions of vibrations per second can cause huge internal pressure changes in the natural gas hydrate particles. Due to the internal pressure changes, the structure of natural gas hydrate is destroyed, and the gas and water in the natural gas hydrate molecules are separated. After ultrasonic treatment, the gas in the natural gas hydrate is released, while the water exists in liquid form. Through the above process, ultrasonic waves can effectively eliminate natural gas hydrate. In the process of natural gas extraction and transportation, natural gas hydrate can be prevented from clogging pipelines and equipment, improving production efficiency and safety.

[0021] The above-mentioned gas well antifreeze production equipment can be further optimized and / or improved according to actual needs: Example 2 is a further optimization of the above examples, as shown in the attached figure. Figure 1 , 2As shown, an inlet flange 12 is fixedly installed on the left side of the valve body 1 corresponding to the inlet 4 position. The outer side of the inlet flange 12 is provided with a first mounting hole that communicates with the inside and outside. A pressure sensor 18 is sealed and installed in the first mounting hole. An outlet flange 13 is fixedly installed on the lower side of the valve body 1 corresponding to the outlet 5 position. The outer side of the outlet flange 13 is provided with a second mounting hole that communicates with the inside and outside. A temperature and pressure sensor 14 is sealed and installed in the second mounting hole. Both the pressure sensor 18 and the temperature and pressure sensor 14 are connected to the control module.

[0022] As required, pressure sensor 18 and temperature-pressure sensor 14 are both existing known technologies. During use, by setting inlet flange 12 and outlet flange 13, the connection between valve body 1 and wellhead pipeline is facilitated. Pressure sensor 18 and temperature-pressure sensor 14 can collect pressure difference and temperature data between inlet 4 and outlet 5 in real time, and can monitor the state of natural gas hydrate in valve cavity 3 in real time, so as to provide timely feedback to the control module. The control module sends ultrasonic generator 11 into valve cavity 3, thereby preventing the formation of natural gas hydrate in valve cavity 3 and preventing freezing blockage in valve cavity 3.

[0023] Example 3 is a further optimization of the above examples, as shown in the appendix. Figure 1 As shown, the ultrasonic generator 11 is an ultrasonic probe.

[0024] According to the requirements, the ultrasonic probe is a known existing technology. The ultrasonic probe includes a probe housing, a sealing cap, a piezoelectric ceramic plate, a signal line sealing plug, and a base. The emission direction of the ultrasonic generator 11 corresponds to the inlet 4 (the direction of the ultrasonic probe emitting ultrasonic waves is directly opposite the inlet 4). In this way, the control module can emit ultrasonic waves into the valve cavity 3 through the ultrasonic generator 11. The emitted ultrasonic waves interfere with the growth of natural gas hydrate crystals in the valve cavity 3, thereby preventing the formation of natural gas hydrates in the valve cavity 3.

[0025] Example 4 is a further optimization of the above examples, as shown in the appendix. Figure 1 As shown, a valve seat 15 is fixedly installed on the upper part of the outlet 5. The valve seat 15 has a tapered throttling hole 9 that runs vertically through the center and is larger at the top and smaller at the bottom. The outer side of the valve core 7 matches the inner wall of the throttling hole 9.

[0026] This allows for quick closure of outlet 5, and the flow rate can be adjusted by controlling the valve core 7 up and down according to production conditions via the control module and drive mechanism 2.

[0027] Example 5 is a further optimization of the above examples, as shown in the appendix. Figure 1 As shown, a filter sleeve 16 is fixedly installed on the upper end of the valve seat 15 and fitted onto the outside of the valve stem 6. Several filter holes 17 with internal and external communication are distributed at intervals on the outside of the filter sleeve 16.

[0028] During use, by setting the filter hole 17, the foam in the valve cavity 3 can be eliminated, so that the ultrasonic waves emitted by the ultrasonic generator 11 can act on the natural gas hydrate.

[0029] Example 6: The control method of the gas well anti-freezing and anti-blocking production device includes the following steps: S1 connects the inlet flange 12 to the gas well outlet 5; S2, the pressure at inlet 4, the temperature at outlet 5, and the pressure at outlet 5 are obtained from pressure sensor 18 and temperature and pressure sensor 14, respectively; S3, Based on the natural gas hydrate formation model, establish judgment conditions, and start the ultrasonic generator 11 when the production conditions meet the judgment conditions; S4. When the pressure at outlet 5 and the pressure at inlet 4 are the same, turn off ultrasonic generator 11, and the gas well enters the continuous production stage. Repeat steps S2 and S3.

[0030] Based on the requirements, the natural gas hydrate formation model is an existing well-known technology, such as two empirical or semi-empirical models (KK and regression formulas) and a thermodynamic phase equilibrium theory model. This invention can provide early warning and control of the working state of gas wells, reduce or eliminate the occurrence of freezing and blockage problems. It has advantages such as real-time performance, effectiveness and reliability, and has broad application prospects in the gas well development process.

[0031] The first step involves real-time monitoring of the pressure at inlet 4 and outlet 5, as well as the temperature of the medium, during well opening. The second step involves the control module determining, based on the natural gas hydrate formation model, whether the current production conditions are close to the critical conditions for natural gas hydrate formation. The third step involves activating the ultrasonic generator 11 when the natural gas flowing through valve body 1 has reached the conditions for hydrate formation. The ultrasonic generator 11 emits ultrasonic waves to interfere with hydrate crystal growth, thereby preventing the formation of natural gas hydrate. The fourth step involves continuously decreasing pressure after well opening, reducing the pressure difference across valve body 1, gradually eliminating the conditions for natural gas hydrate formation, shutting off the ultrasonic generator 11, and allowing the gas well to enter the continuous production phase, repeating the first step of the process.

[0032] Before intermittent production, the gas well needs to be shut down to allow the oil pressure inside the well to gradually recover. Once a certain oil pressure is reached, the well is opened to ensure that there is enough energy in the well for production. During the well opening process, as production progresses, the downhole energy gradually decreases, and the oil pressure will also gradually decrease. When the oil pressure drops to a level that is basically consistent with the pressure after the valve (outlet 5 pressure), production ends, and the control module can be shut down. If the well is opened for production when the pressure before the valve (inlet 4 pressure) is 7 to 8 MPa, the entire production process generally takes 2 to 3 hours. If the well is opened when the pressure before the valve is around 20 MPa, the entire production process generally lasts 1 to 2 days. Pressure sensor 18 and temperature and pressure sensor 14 can automatically collect temperature and pressure data.

[0033] The control method for the above-mentioned gas well antifreeze production device can be further optimized and / or improved according to actual needs: Example 7 is a further optimization of the above examples, as shown in the appendix. Figure 1 As shown, the determination condition in step S3 is: the temperature of outlet 5 is less than or equal to the temperature warning threshold and the pressure of inlet 4 is greater than or equal to the pressure warning threshold.

[0034] The formation of natural gas hydrates requires two conditions: 1) Low temperature conditions, with temperatures around 2 to 4°C, which are conducive to the formation and stability of hydrates. In this embodiment, the temperature warning threshold is 4°C; 2) High pressure conditions, with pressures greater than 3 MPa, which ensures the stable existence of hydrates. Therefore, the device of this invention needs to monitor the temperature and pressure changes inside the valve body 1 in real time during use. The monitored pressure is the absolute pressure inside the valve body 1, and the pressure warning threshold is 3 MPa.

[0035] In October 2023, a field test was conducted on one well in Block 77 for a period of 5 months. During the production period from October 2022 to March 2023, the wellhead process of this well experienced freezing blockage more than 40 times, which led to a significant reduction in the well's opening rate and affected the gas production of approximately 300,000 cubic meters per well. After the intelligent production device for preventing freezing blockage of the gas well was put into operation in October 2023, the gas well predicted freezing blockage 65 times and activated the ultrasonic generator 1,160 times, ensuring stable production of the test gas well during the winter.

[0036] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A gas well antifreeze and anti-blockage production device, characterized in that... The device includes a valve body, a drive mechanism, an ultrasonic generator, and a control module. The valve body contains a closed valve cavity. An inlet is located on the left side of the valve body, with its right end communicating with the left side of the valve cavity. An outlet is located on the lower side of the valve body, with its upper end communicating with the lower part of the valve cavity. A mounting channel is located on the upper side of the valve body corresponding to the outlet, with its lower end communicating with the upper part of the valve cavity. A valve stem is sealed and installed within the mounting channel. A valve core is fixedly installed at the lower end of the valve stem, capable of closing the outlet when moved downwards and opening the outlet when moved upwards. A connecting bracket is fixedly installed on the upper side of the valve body, and a drive mechanism that allows the valve stem to move up and down is fixedly installed on the upper side of the connecting bracket. A transmitting hole is located on the right side of the valve body corresponding to the inlet, with its left end communicating with the valve cavity. An ultrasonic generator is sealed and installed within the transmitting hole. Both the ultrasonic generator and the drive mechanism are electrically connected to the control module.

2. The gas well antifreeze production device according to claim 1, characterized in that... An inlet flange is fixedly installed on the left side of the valve body corresponding to the inlet position. The outer side of the inlet flange has a first mounting hole that connects the inside and outside. A pressure sensor is sealed and installed in the first mounting hole. An outlet flange is fixedly installed on the lower side of the valve body corresponding to the outlet position. The outer side of the outlet flange has a second mounting hole that connects the inside and outside. A temperature and pressure sensor is sealed and installed in the second mounting hole. Both the pressure sensor and the temperature and pressure sensor are connected to the control module.

3. The gas well antifreeze production device according to claim 1 or 2, characterized in that... The ultrasonic generator is an ultrasonic probe.

4. The gas well antifreeze production device according to claim 3, characterized in that... A valve seat is fixedly installed at the upper part of the outlet. The valve seat has a tapered throttling orifice that runs vertically through the center and is wider at the top and narrower at the bottom. The outer side of the valve core matches the inner wall of the throttling orifice.

5. The gas well antifreeze production device according to claim 4, characterized in that... A filter sleeve is fixedly installed on the upper end of the valve seat and fitted onto the outside of the valve stem. Several filter holes with internal and external communication are distributed at intervals on the outside of the filter sleeve.

6. A control method for the gas well antifreeze production device according to any one of claims 3 to 5, characterized in that, Includes the following steps: S1 connects the inlet flange to the gas well outlet; S2, obtains the inlet pressure, outlet temperature and outlet pressure respectively based on the pressure sensor and the temperature and pressure sensor; S3. Based on the natural gas hydrate formation model, establish judgment conditions. When the production conditions meet the judgment conditions, start the ultrasonic generator. S4. When the outlet pressure and inlet pressure are the same, turn off the ultrasonic generator and the gas well enters the continuous production stage. Repeat steps S2 and S3.

7. The control method for the gas well antifreeze production device according to claim 6, characterized in that, The determination conditions in step S3 are: the outlet temperature is less than or equal to the temperature warning threshold and the inlet pressure is greater than or equal to the pressure warning threshold.

Images