Anti-condensation device, method and system

Abstract

The application provides a retrograde condensation device, method and system. The retrograde condensation device is arranged at a well head and connected with a pipe string in a wellbore. The device comprises a pressure control equipment with a fluid passage. The fluid passage is used for the flow of produced fluid in the pipe string to the outside. A control component is arranged in the fluid passage and fixed to the inner wall of the passage. The control component is filled with pressure fluid and the pressure of the control component is maintained at a preset pressure value. The retrograde condensation method is applied to the retrograde condensation device. The retrograde condensation system comprises the retrograde condensation device and a software control center. The beneficial effects of the application include the following: the control component of the pressure control equipment blocks the produced fluid, the pressure in the well is increased, the bottom hole pressure is controlled, and the retrograde condensation is achieved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to an anti-condensation device, method and system suitable for condensate oil and gas reservoirs. Background Technology

[0002] Condensation refers to the process by which hydrocarbon gases, extracted from deep underground under high temperature and pressure conditions, change from a gaseous to a liquid state due to the decrease in temperature and pressure. This liquid, light oil is called condensate oil, and the resulting oil and gas reservoir is called a condensate gas reservoir. Condensate gas reservoirs are a type of oil and gas reservoir that falls between oil and gas reservoirs. Condensate gas reservoirs are generally developed using a depletion-type development approach. However, when this approach enters the middle and late stages, insufficient reservoir energy and formation pressure below the dew point pressure easily lead to condensation contamination. This results in the formation of large amounts of condensate oil in the near-wellbore reservoir zone. Due to difficulties in flow, the condensate oil remains trapped in the near-wellbore reservoir, directly causing a sharp decrease in reservoir permeability, obstructing gas flow in the far-wellbore zone, reducing single-well productivity, rapidly decreasing oil and gas production, and lowering the overall oil and gas recovery rate.

[0003] Currently, common methods for reverse condensation include: firstly, rationally adjusting the producing layer, optimizing the well network, well spacing, and well type, and rationally adjusting the production system of oil and gas wells; secondly, supplementing reservoir energy and using chemical and engineering methods, such as gas injection, methanol injection, mutual solvent injection, steam huff and puff, heating the reservoir, and repeated fracturing.

[0004] In practical applications of existing technologies, the main focus is on addressing condensation contamination by injecting chemical reagents or performing repeated fracturing when the contamination has already occurred. There are few methods or devices that integrate prevention and control of condensation from an early prevention perspective, and there is a complete lack of methods or devices to prevent condensation from the wellhead by controlling the production system.

[0005] Therefore, it is necessary to study an integrated anti-condensation device, method, and system for wellhead prevention and control in order to solve the above problems or mitigate their impact. Summary of the Invention

[0006] This invention provides a reverse condensation device that uses the control components of a pressure control device to block the produced fluid, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of reverse condensation. This can effectively solve or alleviate the aforementioned technical problems.

[0007] The anti-condensation device of the present invention is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. The fluid channel is provided with a control component fixed to the inner wall of the channel. The control component is filled with pressurized fluid and its pressure is maintained at a preset pressure value.

[0008] The control component can expand and seal the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to create pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation.

[0009] In one embodiment, the control component is a ring-shaped pressure ring. The outer ring of the ring-shaped pressure ring is fixedly installed on the inner wall of the fluid channel. The ring body of the ring-shaped pressure ring is filled with the pressurized fluid, and the ring-shaped pressure ring can expand its inner ring towards the center and close under the pressure of the pressurized fluid to seal the fluid channel.

[0010] In one embodiment, the ring pressure ring is connected to a ring pressure control component, which is used to inject the pressure fluid into the ring pressure ring and to maintain the pressure of the pressure fluid in the ring pressure ring at the preset pressure value.

[0011] In one embodiment, the inlet end of the pressure control device is provided with a pressure detector that detects the wellhead pressure of the produced fluid. The pressure detector is electrically connected to the annular pressure control component, and the annular pressure control component can adjust the magnitude of the preset pressure value according to the wellhead pressure value detected by the pressure detector.

[0012] In one embodiment, the anti-condensation apparatus further includes a heating device, which is connected in sequence with the pressure control device in the flow direction of the produced fluid, and the heating device is capable of increasing the temperature of the produced fluid.

[0013] In one embodiment, the heating device is equipped with a control component and a temperature detector. The temperature detector is electrically connected to the control component, and the control component can control the heating device to heat the extracted fluid based on the temperature information detected by the temperature detector.

[0014] In another aspect, the present invention provides a method for anti-condensation, wherein the method is applied to the anti-condensation apparatus described above, and includes at least the following steps:

[0015] The pressure control components of the pressure control device in the anti-condensation apparatus are filled with pressurized fluid and the pressure is maintained at a preset pressure value.

[0016] When the wellhead pressure value of the produced fluid reaches the wellhead is not greater than the preset pressure value, the control component closes the fluid channel of the pressure control device to block the outflow of the produced fluid and create pressure buildup in the well, thus preventing the wellhead pressure from dropping to the point of condensation.

[0017] In one embodiment, the preset pressure value is not less than the critical wellhead pressure value corresponding to the point when condensation is about to occur in the bottom gas phase.

[0018] In one embodiment, the anti-condensation method further includes the step of:

[0019] The wellhead temperature of the produced fluid is detected by a temperature detector. When the wellhead temperature is lower than the minimum temperature at which wax easily forms, the heating equipment is turned on to heat the produced fluid.

[0020] In another aspect, the present invention provides a condensation system, the condensation system comprising the condensation apparatus as described above and a software control center, the software control center being electrically connected to the condensation apparatus, and the software control center being capable of controlling the condensation apparatus to perform operations according to a preset logic control program.

[0021] The anti-condensation apparatus provided by the present invention has at least the following advantages compared with the prior art:

[0022] The anti-condensation device of this invention can block the produced fluid when the pressure at the wellhead is too low by using the control components of the pressure control equipment, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of anti-condensation. This allows for the prevention and control of condensation pollution by establishing a reasonable production system and utilizing the anti-condensation device, thereby ensuring the production capacity and recovery rate of oil and gas reservoirs.

[0023] The anti-condensation method provided by the present invention, when applied to the aforementioned anti-condensation apparatus, also possesses the aforementioned beneficial effects.

[0024] The anti-condensation system provided by the present invention, since it includes the anti-condensation device described above, also has the aforementioned beneficial effects. Attached Figure Description

[0025] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of the anti-condensation apparatus according to an embodiment of the present invention.

[0027] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale.

[0028] Figure label:

[0029] 1-Pressure control equipment, 2-Control components, 3-Ring pressure control components, 4-Pressure detector, 5-Heating equipment, 6-Control components, 7-Temperature detector, 8-Inlet insulating short section, 9-Outlet insulating short section, 10-One-way short section, 11-Auxiliary pressurization equipment, 12-Inlet valve, 13-Outlet valve. Detailed Implementation

[0030] Existing methods for addressing condensation contamination include:

[0031] Tang Kai et al. designed an experimental apparatus and method for simulating liquid phase damage and resolving damage in condensate gas reservoirs. The apparatus includes a high-pressure, high-precision displacement pump, a formation condensate gas container, a formation water container, a natural gas container, a plugging agent container, a vacuum pump, a long core holder, a three-phase separation system, a confining pressure pump, and a backpressure valve. The apparatus simulates combined liquid phase damage from reverse condensation and water lock by injecting water into long cores after reverse condensation damage, and also conducts experiments to resolve liquid phase damage by injecting plugging agents into long cores after reverse condensation and shutting down the well. Multiple permeability values ​​at different stages were obtained to evaluate the degree of liquid phase damage and the effectiveness of damage resolution. Clearly, this is primarily a method for evaluating the degree of reservoir damage; for reservoir reverse condensation, it simply proposes a plugging agent injection method.

[0032] Wang Xinyu et al. designed a method for removing near-wellbore reverse condensate contamination through gas injection in condensate gas wells. First, the condensate gas well blocked by reverse condensate is selected, and the wellbore is shut in to remove the accumulated liquid. Then, the production well is converted into an injection well, and natural gas that has undergone deoiling, dehydration, and impurity removal is injected into the well. After injection, the wellhead pressure is observed after shutting in. If the pressure approaches the pre-injection shut-in pressure, it indicates that the injected gas has diffused into a relatively distant formation, and normal production can be resumed. Clearly, this is a method for removing reverse condensate contamination through gas injection.

[0033] Wu Zhijun et al. designed a method for rapidly removing condensate gas reservoir contamination. First, nitrogen is injected into the gas layer, then ethanol, followed by another injection of nitrogen, well shut-off, and fluid drainage, thus rapidly removing the contamination. Clearly, this method only addresses situations where condensate contamination has already occurred and proposes a chemical reagent injection approach for resolving it.

[0034] Wang Moran et al. designed a method to suppress reverse condensation in condensate gas reservoirs. First, they monitored the gas production and reservoir parameters of the well according to a pre-set cycle. Then, based on the gas production and reservoir parameters, they determined the power of a heating resistor using a predetermined algorithm. The heating resistor was pre-installed inside the well casing or on the oil pipeline cable. Finally, the actual power of the heating resistor was adjusted according to the determined power, thus achieving the purpose of suppressing reverse condensation in condensate gas reservoirs through heating. Clearly, its main application is in wellbore heating for reverse condensation.

[0035] Zhang Chong et al. designed a method and system for removing contamination from the anti-condensation zone. First, they side-drilled the casing of the target well along a predetermined direction of the target reservoir. Then, they hydraulically fractured the original artificial fractures to create new artificial fractures. Next, they injected a carrying fluid containing sealing material into the new artificial fractures to temporarily plug them. Finally, they hydraulically fractured the side-drilled anti-condensation zone to form a fracture system, ultimately removing contamination from the entire anti-condensation zone. Clearly, this only proposes a method similar to repeated hydraulic fracturing to remove contamination from the entire anti-condensation zone.

[0036] In summary, current methods for preventing condensation in condensate gas reservoirs primarily involve replenishing formation energy and employing chemical and fracturing techniques, such as gas injection, methanol injection, and repeated fracturing, once condensation contamination has occurred. However, the reduction in energy in condensate gas reservoirs is largely due to inefficient production practices. There are few integrated prevention-control methods and devices for preventing condensation from an early stage, and prevention of condensation at the wellhead by controlling the production system is completely lacking. Therefore, the integrated wellhead prevention-control anti-condensation device, method, and system proposed in this invention are of significant importance.

[0037] The invention will now be further described with reference to the accompanying drawings.

[0038] Example 1

[0039] like Figure 1 As shown, the anti-condensation device of the present invention is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device 1 with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. A control component 2 is fixed to the inner wall of the fluid channel. The control component 2 is filled with pressurized fluid and its pressure is maintained at a preset pressure value.

[0040] Among them, the control component 2 can expand and close the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to form pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation.

[0041] Specifically, the anti-condensation device is installed at the wellhead, with its inlet end connected to the tubing string inside the wellbore and its outlet end connected to the pipeline network. The core component of the anti-condensation device includes a pressure control device 1, which has at least one fluid channel inside. The main function of the fluid channel is to provide a smooth flow path for the produced fluid inside the tubing string, allowing it to flow to the pipeline network.

[0042] The pressure control device 1 has a control component 2 installed at a key location in the fluid channel. The control component 2 is fixed to the inner wall of the fluid channel, and its interior is filled with a specific pressurized fluid, the pressure of which is controlled at a preset value. This causes the control component 2 to expand and contract under the pressure difference between the internal pressurized fluid and the extracted fluid flowing into the pressure control device 1. Specifically:

[0043] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure of the pressure fluid in the control component 2, the produced fluid can squeeze the control component 2 to make the fluid channel unobstructed, that is, the produced fluid can flow to the pipeline network through the pressure control device 1.

[0044] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is not greater than (i.e., less than or equal to) the preset pressure value of the fluid in the control component 2, the produced fluid cannot compress the control component 2 to make the fluid channel unobstructed. Instead, the control component 2 expands to fill the entire fluid channel, forming a seal and thus preventing the produced fluid from flowing out. In other words, the produced fluid cannot flow to the pipeline network through the pressure control device 1, but instead is pressurized from the wellhead into the well, thus acting on the bottom of the well and increasing the formation pressure at the bottom. This avoids condensation contamination caused by a drop in formation pressure at the bottom of the well, thereby achieving the purpose of anti-condensation.

[0045] Overall, the anti-condensation device can block the produced fluid through the control component 2 of the pressure control equipment 1 when the pressure of the produced fluid reaching the wellhead is too low, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of anti-condensation. In this way, by setting a reasonable production system, the anti-condensation device can prevent and control the occurrence of condensation pollution, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0046] Example 2

[0047] like Figure 1 As shown, the anti-condensation device of the present invention is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device 1 with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. A control component 2 is fixed to the inner wall of the fluid channel. The control component 2 is filled with pressurized fluid and its pressure is maintained at a preset pressure value.

[0048] Among them, the control component 2 can expand and close the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to form pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation.

[0049] Overall, the anti-condensation device can block the produced fluid through the control component 2 of the pressure control equipment 1 when the pressure of the produced fluid reaching the wellhead is too low, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of anti-condensation. In this way, by setting a reasonable production system, the anti-condensation device can prevent and control the occurrence of condensation pollution, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0050] In one example, such as Figure 1 As shown, the control component 2 is a ring-shaped pressure ring. The outer ring of the ring-shaped pressure ring is fixedly laid on the inner wall of the fluid channel. The ring body of the ring-shaped pressure ring is filled with pressurized fluid, and the ring-shaped pressure ring can expand its inner ring towards the center under the pressure of the pressurized fluid to close the fluid channel.

[0051] Specifically, the ring pressure ring has a ring-shaped structure and is made of an elastic material. The outer ring side of the ring pressure ring is fixed to the inner wall of the fluid channel, and the outer ring side is sealed to the inner wall of the channel, meaning there is no gap between the outer ring side and the inner wall of the channel for the sampled fluid to pass through. The inner ring of the ring pressure ring forms a channel for the sampled fluid to flow through. The inside of the ring body is filled with pressurized fluid. The presence of pressurized fluid allows the ring pressure ring to respond rapidly when there is a pressure difference between the internal and external pressures of the ring body.

[0052] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid can squeeze the annular pressure ring to make the fluid passage unobstructed. When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid cannot squeeze the annular pressure ring to make the fluid passage unobstructed. Instead, the annular pressure ring expands, causing its inner ring to squeeze towards the center and fill the entire fluid passage to form a seal, thereby preventing the produced fluid from flowing out.

[0053] Clearly, the outer ring of the compression ring is fixedly laid on the inner wall of the fluid channel, serving as the fixed connection end of the compression ring and ensuring its stability and reliability during operation. The inner ring of the compression ring can expand and contract under the pressure of the fluid within the ring body, acting as its functional part to block or open the fluid channel. It can quickly respond and implement control, ensuring that the fluid channel can be effectively closed when needed.

[0054] In one example, the ring pressure ring is connected to a ring pressure control element 3, which is used to inject pressurized fluid into the ring pressure ring and can maintain the pressure of the pressurized fluid inside the ring pressure ring at a preset pressure value.

[0055] Specifically, the ring pressure control component 3 can be installed outside the pressure control device 1 and connected to the inside of the ring body of the ring pressure ring through a pipe for transmitting pressure fluid. In this way, the pressure of the pressure fluid inside the ring pressure ring can be maintained at a preset pressure value by controlling the injection or discharge of pressure fluid into the ring pressure ring.

[0056] One of the functions of the ring pressure control component 3 is to inject pressurized fluid into the ring pressure ring, ensuring that the inside of the ring pressure ring is filled with pressurized fluid and that the pressurized fluid is evenly distributed inside the ring pressure ring, thereby ensuring the overall stability and reliability of the ring pressure ring.

[0057] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure ring. Through advanced control technology and a precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure ring in real time by injecting or discharging pressurized fluid, ensuring that it is always maintained at the preset pressure value. This function is crucial for ensuring the normal operation of the anti-condensation unit. It can discharge the pressurized fluid in the ring pressure ring when the produced fluid pressure is high, causing the ring pressure ring to contract and thus keeping the fluid passage of the pressure control device 1 unobstructed; and it can inject pressurized fluid into the ring pressure ring when the produced fluid pressure is low, causing the ring pressure ring to expand and thus closing the fluid passage of the pressure control device 1.

[0058] In one example, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the annular pressure control component 3, and the annular pressure control component 3 can adjust the preset pressure value according to the wellhead pressure value detected by the pressure detector 4.

[0059] Specifically, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 has real-time monitoring and certain data analysis functions, and can accurately capture the dynamic changes of the wellhead pressure and transmit the relevant data.

[0060] An electrical connection is established between the pressure detector 4 and the annular pressure control component 3, forming a bridge for information exchange. The pressure data detected by the pressure detector 4 can be transmitted to the annular pressure control component 3. As the core component for adjusting the pressure of the annular rubber ring in the pressure control device 1, the annular pressure control component 3 can adjust the preset pressure value in a timely manner according to the wellhead pressure value transmitted in real time by the pressure detector 4.

[0061] In this way, at different stages of oil and gas extraction, the preset pressure value can be adjusted and controlled according to the degree of pressure decay in the oil and gas reservoir formation and the wellhead pressure changes of the produced fluid reaching the wellhead. This is to match the designed reasonable extraction and production system, prevent and control the occurrence of condensation pollution, and thus ensure the production capacity and recovery rate of the oil and gas reservoir.

[0062] Example 3

[0063] like Figure 1 As shown, the anti-condensation device of the present invention is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device 1 with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. A control component 2 is fixed to the inner wall of the fluid channel. The control component 2 is filled with pressurized fluid and its pressure is maintained at a preset pressure value.

[0064] Among them, the control component 2 can expand and close the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to form pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation.

[0065] Overall, the anti-condensation device can block the produced fluid through the control component 2 of the pressure control equipment 1 when the pressure of the produced fluid reaching the wellhead is too low, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of anti-condensation. In this way, by setting a reasonable production system, the anti-condensation device can prevent and control the occurrence of condensation pollution, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0066] In one example, such as Figure 1 As shown, the control component 2 is a ring-shaped pressure ring. The outer ring of the ring-shaped pressure ring is fixedly laid on the inner wall of the fluid channel. The ring body of the ring-shaped pressure ring is filled with pressurized fluid, and the ring-shaped pressure ring can expand its inner ring towards the center under the pressure of the pressurized fluid to close the fluid channel.

[0067] Specifically, the ring pressure ring has a ring-shaped structure and is made of an elastic material. The outer ring side of the ring pressure ring is fixed to the inner wall of the fluid channel, and the outer ring side is sealed to the inner wall of the channel, meaning there is no gap between the outer ring side and the inner wall of the channel for the sampled fluid to pass through. The inner ring of the ring pressure ring forms a channel for the sampled fluid to flow through. The inside of the ring body is filled with pressurized fluid. The presence of pressurized fluid allows the ring pressure ring to respond rapidly when there is a pressure difference between the internal and external pressures of the ring body.

[0068] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid can squeeze the annular pressure ring to make the fluid passage unobstructed. When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid cannot squeeze the annular pressure ring to make the fluid passage unobstructed. Instead, the annular pressure ring expands, causing its inner ring to squeeze towards the center and fill the entire fluid passage to form a seal, thereby preventing the produced fluid from flowing out.

[0069] Clearly, the outer ring of the compression ring is fixedly laid on the inner wall of the fluid channel, serving as the fixed connection end of the compression ring and ensuring its stability and reliability during operation. The inner ring of the compression ring can expand and contract under the pressure of the fluid within the ring body, acting as its functional part to block or open the fluid channel. It can quickly respond and implement control, ensuring that the fluid channel can be effectively closed when needed.

[0070] In one example, the ring pressure ring is connected to a ring pressure control element 3, which is used to inject pressurized fluid into the ring pressure ring and can maintain the pressure of the pressurized fluid inside the ring pressure ring at a preset pressure value.

[0071] Specifically, the ring pressure control component 3 can be installed outside the pressure control device 1 and connected to the inside of the ring body of the ring pressure ring through a pipe for transmitting pressure fluid. In this way, the pressure of the pressure fluid inside the ring pressure ring can be maintained at a preset pressure value by controlling the injection or discharge of pressure fluid into the ring pressure ring.

[0072] One of the functions of the ring pressure control component 3 is to inject pressurized fluid into the ring pressure ring, ensuring that the inside of the ring pressure ring is filled with pressurized fluid and that the pressurized fluid is evenly distributed inside the ring pressure ring, thereby ensuring the overall stability and reliability of the ring pressure ring.

[0073] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure ring. Through advanced control technology and a precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure ring in real time by injecting or discharging pressurized fluid, ensuring that it is always maintained at the preset pressure value. This function is crucial for ensuring the normal operation of the anti-condensation unit. It can discharge the pressurized fluid in the ring pressure ring when the produced fluid pressure is high, causing the ring pressure ring to contract and thus keeping the fluid passage of the pressure control device 1 unobstructed; and it can inject pressurized fluid into the ring pressure ring when the produced fluid pressure is low, causing the ring pressure ring to expand and thus closing the fluid passage of the pressure control device 1.

[0074] In one example, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the annular pressure control component 3, and the annular pressure control component 3 can adjust the preset pressure value according to the wellhead pressure value detected by the pressure detector 4.

[0075] Specifically, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 has real-time monitoring and certain data analysis functions, and can accurately capture the dynamic changes of the wellhead pressure and transmit the relevant data.

[0076] An electrical connection is established between the pressure detector 4 and the annular pressure control component 3, forming a bridge for information exchange. The pressure data detected by the pressure detector 4 can be transmitted to the annular pressure control component 3. As the core component for adjusting the pressure of the annular rubber ring in the pressure control device 1, the annular pressure control component 3 can adjust the preset pressure value in a timely manner according to the wellhead pressure value transmitted in real time by the pressure detector 4.

[0077] In this way, at different stages of oil and gas extraction, the preset pressure value can be adjusted and controlled according to the degree of pressure decay in the oil and gas reservoir formation and the wellhead pressure changes of the produced fluid reaching the wellhead. This is to match the designed reasonable extraction and production system, prevent and control the occurrence of condensation pollution, and thus ensure the production capacity and recovery rate of the oil and gas reservoir.

[0078] In one example, such as Figure 1As shown, the anti-condensation device also includes a heating device 5, which is connected in sequence with the pressure control device 1 in the flow direction of the extracted fluid. The heating device 5 can increase the temperature of the extracted fluid.

[0079] Specifically, the inlet end of the heating device 5 is connected to the tubing inside the wellbore, and the outlet end of the heating device 5 is connected to the inlet end of the pressure control device 1. That is, the produced fluid flowing out of the tubing first passes through the heating device 5 and then flows through the pressure control device 1.

[0080] The anti-condensation unit can heat the extracted fluid through heating device 5 to increase the temperature of the extracted fluid, which can prevent wax from forming due to low temperature of the extracted fluid and has the functions of preventing wax and removing wax.

[0081] Furthermore, the coordinated operation of heating device 5 and pressure control device 1 can greatly improve the overall performance of the anti-condensation unit. By maintaining the temperature of the produced fluid through heating, beneficial changes can occur in the physical properties of the produced fluid, such as reduced viscosity and increased fluidity. This helps the produced fluid pass more smoothly through pressure control device 1 and the pipeline network, reducing the risk of blockage and condensation.

[0082] It should be noted that the pressure detector 4 can be installed on the heating device 5 to detect the wellhead pressure value of the produced fluid at the inlet of the pressure control device 1.

[0083] In one example, the heating device 5 is equipped with a control component 6 and a temperature detector 7. The temperature detector 7 is electrically connected to the control component 6, and the control component 6 can control the heating device 5 to heat the extracted fluid based on the temperature information detected by the temperature detector 7.

[0084] Specifically, the heating device 5 is equipped with a control component 6 and a temperature detector 7 to achieve precise control of the heating device 5. The temperature detector 7 has high sensitivity and high accuracy, and has real-time monitoring and certain data analysis functions. It can accurately capture the dynamic changes in wellhead temperature and transmit relevant data.

[0085] An electrical connection is established between the temperature detector 7 and the control component 6, forming a bridge for information exchange. The temperature data detected by the temperature detector 7 can be transmitted to the control component 6. The control component 6 is the control core of the heating device 5 and can control the heating device 5 to turn heating on or off based on the wellhead temperature value transmitted in real time by the temperature detector 7. Specifically:

[0086] If the temperature detector 7 detects that the wellhead temperature of the produced fluid is too low (generally below the minimum temperature at which wax easily forms in the produced fluid), the control component 6 controls the heating device 5 to turn on, heating the produced fluid to increase its temperature and thus prevent and remove wax. When the temperature of the produced fluid rises (reaching the minimum temperature at which wax easily forms in the produced fluid) and stabilizes, the control component 6 controls the heating device 5 to turn off, stopping the heating.

[0087] Furthermore, the heating device 5 is equipped with an electric heating grid inside, and the control component 6 includes an adjustment switch, which can control and adjust the heating power and on / off state of the electric heating grid.

[0088] Specifically, the temperature detector 7 monitors the temperature of the extracted fluid in real time and transmits the temperature information to the control component 6. Based on the received temperature information, the control component 6 intelligently determines whether to switch the electric heating grid on or off, or adjust the heating power of the electric heating grid. In this way, through the precise control of the adjustment switch by the control component 6, the heating equipment 5 can ensure that the temperature of the extracted fluid is always maintained within the ideal temperature range, which can prevent the extracted fluid from being too cold and forming wax, and also avoid the safety risks that may be caused by excessively high temperatures.

[0089] Example 4

[0090] like Figure 1 As shown, the anti-condensation device of the present invention is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device 1 with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. A control component 2 is fixed to the inner wall of the fluid channel. The control component 2 is filled with pressurized fluid and its pressure is maintained at a preset pressure value.

[0091] Among them, the control component 2 can expand and close the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to create pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation.

[0092] Specifically, the anti-condensation device is installed at the wellhead, with its inlet end connected to the tubing string inside the wellbore and its outlet end connected to the pipeline network. The core component of the anti-condensation device includes a pressure control device 1, which has at least one fluid channel inside. The main function of the fluid channel is to provide a smooth flow path for the produced fluid inside the tubing string, allowing it to flow to the pipeline network.

[0093] The pressure control device 1 has a control component 2 installed at a key location in the fluid channel. The control component 2 is fixed to the inner wall of the fluid channel, and its interior is filled with a specific pressurized fluid, the pressure of which is controlled at a preset value. This causes the control component 2 to expand and contract under the pressure difference between the internal pressurized fluid and the extracted fluid flowing into the pressure control device 1. Specifically:

[0094] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure of the pressure fluid in the control component 2, the produced fluid can squeeze the control component 2 to make the fluid channel unobstructed, that is, the produced fluid can flow to the pipeline network through the pressure control device 1.

[0095] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is not greater than (i.e., less than or equal to) the preset pressure value of the fluid in the control component 2, the produced fluid cannot compress the control component 2 to make the fluid channel unobstructed. Instead, the control component 2 expands to fill the entire fluid channel, forming a seal and thus preventing the produced fluid from flowing out. In other words, the produced fluid cannot flow to the pipeline network through the pressure control device 1, but instead is pressurized from the wellhead into the well, thus acting on the bottom of the well and increasing the formation pressure at the bottom. This avoids condensation contamination caused by a drop in formation pressure at the bottom of the well, thereby achieving the purpose of anti-condensation.

[0096] Overall, the anti-condensation device can block the produced fluid through the control component 2 of the pressure control equipment 1 when the pressure of the produced fluid reaching the wellhead is too low, causing pressure buildup in the well and thus controlling the bottom hole pressure to achieve the purpose of anti-condensation. In this way, by setting a reasonable production system, the anti-condensation device can prevent and control the occurrence of condensation pollution, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0097] In one example, such as Figure 1 As shown, the control component 2 is a ring-shaped pressure ring. The outer ring of the ring-shaped pressure ring is fixedly laid on the inner wall of the fluid channel. The ring body of the ring-shaped pressure ring is filled with pressurized fluid, and the ring-shaped pressure ring can expand its inner ring towards the center under the pressure of the pressurized fluid to close the fluid channel.

[0098] Specifically, the ring pressure ring has a ring-shaped structure and is made of an elastic material. The outer ring side of the ring pressure ring is fixed to the inner wall of the fluid channel, and the outer ring side is sealed to the inner wall of the channel, meaning there is no gap between the outer ring side and the inner wall of the channel for the sampled fluid to pass through. The inner ring of the ring pressure ring forms a channel for the sampled fluid to flow through. The inside of the ring body is filled with pressurized fluid. The presence of pressurized fluid allows the ring pressure ring to respond rapidly when there is a pressure difference between the internal and external pressures of the ring body.

[0099] When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid can squeeze the annular pressure ring to make the fluid passage unobstructed. When the wellhead pressure of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure of the fluid inside the annular pressure ring, the produced fluid cannot squeeze the annular pressure ring to make the fluid passage unobstructed. Instead, the annular pressure ring expands, causing its inner ring to squeeze towards the center and fill the entire fluid passage to form a seal, thereby preventing the produced fluid from flowing out.

[0100] Clearly, the outer ring of the compression ring is fixedly laid on the inner wall of the fluid channel, serving as the fixed connection end of the compression ring and ensuring its stability and reliability during operation. The inner ring of the compression ring can expand and contract under the pressure of the fluid within the ring body, acting as its functional part to block or open the fluid channel. It can quickly respond and implement control, ensuring that the fluid channel can be effectively closed when needed.

[0101] In one example, the ring pressure ring is connected to a ring pressure control element 3, which is used to inject pressurized fluid into the ring pressure ring and can maintain the pressure of the pressurized fluid inside the ring pressure ring at a preset pressure value.

[0102] Specifically, the ring pressure control component 3 can be installed outside the pressure control device 1 and connected to the inside of the ring body of the ring pressure ring through a pipe for transmitting pressure fluid. In this way, the pressure of the pressure fluid inside the ring pressure ring can be maintained at a preset pressure value by controlling the injection or discharge of pressure fluid into the ring pressure ring.

[0103] One of the functions of the ring pressure control component 3 is to inject pressurized fluid into the ring pressure ring, ensuring that the inside of the ring pressure ring is filled with pressurized fluid and that the pressurized fluid is evenly distributed inside the ring pressure ring, thereby ensuring the overall stability and reliability of the ring pressure ring.

[0104] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure ring. Through advanced control technology and a precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure ring in real time by injecting or discharging pressurized fluid, ensuring that it is always maintained at the preset pressure value. This function is crucial for ensuring the normal operation of the anti-condensation unit. It can discharge the pressurized fluid in the ring pressure ring when the produced fluid pressure is high, causing the ring pressure ring to contract and thus keeping the fluid passage of the pressure control device 1 unobstructed; and it can inject pressurized fluid into the ring pressure ring when the produced fluid pressure is low, causing the ring pressure ring to expand and thus closing the fluid passage of the pressure control device 1.

[0105] In one example, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the annular pressure control component 3, and the annular pressure control component 3 can adjust the preset pressure value according to the wellhead pressure value detected by the pressure detector 4.

[0106] Specifically, the inlet end of the pressure control device 1 is equipped with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 has real-time monitoring and certain data analysis functions, and can accurately capture the dynamic changes of the wellhead pressure and transmit the relevant data.

[0107] An electrical connection is established between the pressure detector 4 and the annular pressure control component 3, forming a bridge for information exchange. The pressure data detected by the pressure detector 4 can be transmitted to the annular pressure control component 3. As the core component for adjusting the pressure of the annular rubber ring in the pressure control device 1, the annular pressure control component 3 can adjust the preset pressure value in a timely manner according to the wellhead pressure value transmitted in real time by the pressure detector 4.

[0108] In this way, at different stages of oil and gas extraction, the preset pressure value can be adjusted and controlled according to the degree of pressure decay in the oil and gas reservoir formation and the wellhead pressure changes of the produced fluid reaching the wellhead. This is to match the designed reasonable extraction and production system, prevent and control the occurrence of condensation pollution, and thus ensure the production capacity and recovery rate of the oil and gas reservoir.

[0109] In one example, such as Figure 1 As shown, the anti-condensation device also includes a heating device 5, which is connected in sequence with the pressure control device 1 in the flow direction of the extracted fluid. The heating device 5 can increase the temperature of the extracted fluid.

[0110] Specifically, the inlet end of the heating device 5 is connected to the tubing inside the wellbore, and the outlet end of the heating device 5 is connected to the inlet end of the pressure control device 1. That is, the produced fluid flowing out of the tubing first passes through the heating device 5 and then flows through the pressure control device 1.

[0111] The anti-condensation unit can heat the extracted fluid through heating device 5 to increase the temperature of the extracted fluid, which can prevent wax from forming due to low temperature of the extracted fluid and has the functions of preventing wax and removing wax.

[0112] Furthermore, the coordinated operation of heating device 5 and pressure control device 1 can greatly improve the overall performance of the anti-condensation unit. By maintaining the temperature of the produced fluid through heating, beneficial changes can occur in the physical properties of the produced fluid, such as reduced viscosity and increased fluidity. This helps the produced fluid pass more smoothly through pressure control device 1 and the pipeline network, reducing the risk of blockage and condensation.

[0113] It should be noted that the pressure detector 4 can be installed on the heating device 5 to detect the wellhead pressure value of the produced fluid at the inlet of the pressure control device 1.

[0114] In one example, the heating device 5 is equipped with a control component 6 and a temperature detector 7. The temperature detector 7 is electrically connected to the control component 6, and the control component 6 can control the heating device 5 to heat the extracted fluid based on the temperature information detected by the temperature detector 7.

[0115] Specifically, the heating device 5 is equipped with a control component 6 and a temperature detector 7 to achieve precise control of the heating device 5. The temperature detector 7 has high sensitivity and high accuracy, and has real-time monitoring and certain data analysis functions. It can accurately capture the dynamic changes in wellhead temperature and transmit relevant data.

[0116] An electrical connection is established between the temperature detector 7 and the control component 6, forming a bridge for information exchange. The temperature data detected by the temperature detector 7 can be transmitted to the control component 6. The control component 6 is the control core of the heating device 5 and can control the heating device 5 to turn heating on or off based on the wellhead temperature value transmitted in real time by the temperature detector 7. Specifically:

[0117] If the temperature detector 7 detects that the wellhead temperature of the produced fluid is too low (generally below the minimum temperature at which wax easily forms in the produced fluid), the control component 6 controls the heating device 5 to turn on, heating the produced fluid to increase its temperature and thus prevent and remove wax. When the temperature of the produced fluid rises (reaching the minimum temperature at which wax easily forms in the produced fluid) and stabilizes, the control component 6 controls the heating device 5 to turn off, stopping the heating.

[0118] Furthermore, the heating device 5 is equipped with an electric heating grid inside, and the control component 6 includes an adjustment switch, which can control and adjust the heating power and on / off state of the electric heating grid.

[0119] Specifically, the temperature detector 7 monitors the temperature of the extracted fluid in real time and transmits the temperature information to the control component 6. Based on the received temperature information, the control component 6 intelligently determines whether to switch the electric heating grid on or off, or adjust the heating power of the electric heating grid. In this way, through the precise control of the adjustment switch by the control component 6, the heating equipment 5 can ensure that the temperature of the extracted fluid is always maintained within the ideal temperature range, which can prevent the extracted fluid from being too cold and forming wax, and also avoid the safety risks that may be caused by excessively high temperatures.

[0120] In one example, the control component 6 also includes a filling switch disposed on the heating device 5 for filling the heating device 5 with chemical agents.

[0121] Specifically, if the wax deposition in the produced fluid is severe, it will result in low fluidity and make it prone to blockage when transported outward through the pressure control device 1. In this case, chemical agents can be injected into the heating device 5 through the injection switch to remove the paraffin in the produced fluid and further prevent wax deposition, thus achieving the purpose of wax removal and prevention.

[0122] It should be noted that both the filling switch and the regulating switch are part of the control component 6, and their specific installation positions can be adapted to the specific circumstances.

[0123] In one example, the heating device 5 has an inlet insulating section 8 at its front end, an outlet insulating section 9 between the heating device 5 and the pressure control device 1, and a one-way section 10 at the rear end of the pressure control device 1.

[0124] Specifically, an inlet insulating section 8 and an outlet insulating section 9 are respectively provided at the front and rear ends of the heating device 5. These not only serve an insulating function, ensuring electrical isolation between the heating device 5 and the upstream pipeline and the downstream pressure control device 1 to prevent possible current leakage, but also have a certain buffering and vibration reduction function, which can reduce the impact and vibration generated when the extracted fluid enters the heating device 5 and the pressure control device 1, thereby protecting the stability of the heating device 5 and the pressure control device 1 and extending their service life.

[0125] Furthermore, a one-way sub-section 10 is installed at the rear end of the pressure control device 1. Its main function is to prevent backflow of the produced fluid at the rear end of the pressure control device 1. In some cases, due to pressure changes or other factors, backflow may occur, which may affect the normal operation of the pressure control device 1 or even damage it. The design of the one-way sub-section 10 effectively solves this problem, allowing the produced fluid to flow downstream from the pressure control device 1 only, preventing backflow and thus ensuring the stability of the operation of the pressure control device 1.

[0126] By configuring the inlet insulating short section 8, the outlet insulating short section 9, and the unidirectional short section 10, the anti-condensation unit can improve its operating efficiency and safety, enhance its operational stability and durability, and reduce its failure rate and maintenance costs.

[0127] In one example, the anti-condensation unit also includes an auxiliary booster device 11 connected to the rear end of the pressure control device 1, which can increase the pressure of the produced fluid.

[0128] Specifically, the produced fluid flowing from the pressure control device 1 flows into the auxiliary booster device 11 through the one-way sub-section 10. After being pressurized by the auxiliary booster device 11, it flows into the pipeline network. The main function of the auxiliary booster device 11 is to further increase the pressure of the produced fluid so that it can smoothly enter the pipeline network for collection and transportation.

[0129] In one example, the anti-condensation unit also includes an inlet valve 12 located before the inlet insulating stub 8 and an outlet valve 13 located after the auxiliary pressurization device 11.

[0130] Specifically, the inlet valve 12 is located at the front end of the anti-condensation unit, which controls the flow of the produced fluid into the unit. In case of maintenance or emergency, the inlet valve 12 can be quickly closed to cut off the flow of the produced fluid into the unit, ensuring the safety of equipment and personnel.

[0131] The outlet valve 13 is located at the rear end of the device. Its main function is to control the speed and direction of the produced fluid flowing out of the device. In case of shutdown or emergency, the outlet valve 13 can be quickly closed to prevent the produced fluid from continuing to flow out of the device and prevent possible leaks and accidents.

[0132] The addition of inlet valve 12 and outlet valve 13 not only improves the operational flexibility of the anti-condensation unit, but also enhances its safety. In an emergency, the fluid can be quickly shut off to prevent the accident from escalating and protect the safety of equipment and personnel.

[0133] In summary, the anti-condensation device can monitor and control the temperature and pressure of the produced fluid in real time. When the produced fluid pressure is too low, the anti-condensation device can temporarily slow the flow of the produced fluid through the pressure control device 1, causing the pressure inside the well to build up, thereby controlling the bottom hole pressure and achieving the purpose of anti-condensation. When the produced fluid temperature is too low, the anti-condensation device can heat the produced fluid through the heating device 5, thereby increasing the temperature of the produced fluid and achieving the purpose of preventing and removing wax. The anti-condensation device can also add chemical agents to the produced fluid as needed to control and prevent wax formation. It can also further increase the pressure of the produced fluid through the auxiliary pressurization device 11 so that the produced fluid can smoothly enter the pipeline network for collection and transportation.

[0134] Example 5

[0135] The anti-condensation system of the present invention includes the above-mentioned anti-condensation device and a software control center. The software control center is electrically connected to the anti-condensation device, and the software control center can control the anti-condensation device to operate according to a preset logic control program.

[0136] Specifically, the anti-condensation system of the present invention mainly includes two core components: the aforementioned anti-condensation device and the software control center. The two are electrically connected to realize data transmission and command execution, together forming an intelligent and automated anti-condensation control system.

[0137] The software control center possesses powerful data processing and logic control capabilities. It communicates with the reverse condensation unit in real time via electrical connection, receiving data from various devices within the unit, including key parameters such as wellhead pressure, preset pressure values, wellhead temperature, and produced fluid flow rate. Based on this data, the software control center can precisely control the reverse condensation unit using preset logic control programs.

[0138] In practical applications, the software control center calculates corresponding control commands based on the real-time status of the produced fluid and preset control objectives, and sends these commands to the anti-condensation unit via electrical connection. Upon receiving the commands, the anti-condensation unit immediately executes the corresponding actions, such as adjusting the preset pressure value of the pressure control equipment or starting the heating equipment. Simultaneously, the software control center can also adjust and optimize parameters according to actual needs to adapt to anti-condensation control at different wellheads and with different fluid properties.

[0139] Example 6

[0140] The anti-condensation method of the present invention is applied to the above-mentioned anti-condensation apparatus and includes at least the following steps:

[0141] The pressure control components of the pressure control equipment in the anti-condensation unit are filled with pressurized fluid and the pressure is maintained at a preset pressure value.

[0142] By controlling the components to close the fluid channel of the pressure control device when the wellhead pressure value when the produced fluid reaches the wellhead is not greater than the preset pressure value, the outflow of the produced fluid is blocked, causing pressure buildup in the well and preventing the wellhead pressure from dropping to the point of condensation.

[0143] Specifically, the reverse condensation method relies on a reverse condensation device to effectively control the produced fluid. First, pressurized fluid should be injected into the control components of the pressure control equipment within the reverse condensation device. This injection can be achieved through a dedicated annular pressure control component, ensuring the pressure is maintained at a preset value. When the produced fluid flows out of the wellhead, accurate wellhead pressure data can be obtained in real time using a pressure detector within the reverse condensation device. If the detected wellhead pressure is not greater than the preset value, the sealing mechanism of the control components is activated. At this time, the control components rapidly expand under the action of the pressurized fluid injected through the annular pressure control component, tightly sealing the fluid passage of the pressure control equipment. This quickly and effectively blocks the outflow of the produced fluid, creating a pressure-locked state within the well to prevent condensation caused by excessively low well pressure.

[0144] In one example, the preset pressure value is not less than the critical wellhead pressure value corresponding to the point when condensation will occur in the gas phase at the bottom of the well.

[0145] Specifically, in the practical application of the reverse condensation method, setting the preset pressure value is crucial. The wellhead pressure critical value refers to the wellhead pressure value at which condensation begins in the bottom gas phase. When the wellhead pressure is lower than this critical value, the gas components in the bottom gas phase will gradually precipitate out due to the pressure reduction, forming condensate.

[0146] Therefore, when setting the preset pressure value, it must be ensured that it is not less than the critical wellhead pressure value to prevent condensation and ensure the stability and fluidity of the produced fluid. In actual operation, a suitable preset pressure value can be determined by combining theoretical calculations and experimental verification based on the actual wellhead conditions and the properties of the produced fluid. Furthermore, the wellhead pressure will change at different stages of oil and gas well production, and the preset pressure value needs to be adjusted promptly according to these changes to ensure that, under a reasonable production regime, the anti-condensation device can prevent and control condensation contamination, thereby guaranteeing the reservoir's productivity and recovery rate.

[0147] In one example, the reverse condensation method also includes the steps of: detecting the wellhead temperature of the produced fluid when it reaches the wellhead using a temperature detector, and turning on the heating equipment to heat the produced fluid when the wellhead temperature is lower than the minimum temperature at which wax easily forms.

[0148] Specifically, in implementing the reverse condensation method, in addition to controlling the wellhead pressure to prevent condensation, it is also necessary to pay attention to the temperature of the produced fluid. Low temperatures can lead to wax deposition, which severely affects the fluid's flowability and may even cause blockages in pipelines and equipment. Therefore, a temperature detector is needed to monitor the wellhead temperature in real time when the produced fluid reaches the wellhead, and heating equipment should be used for wax prevention and removal.

[0149] When the temperature detector detects that the wellhead temperature is lower than the minimum temperature at which wax easily forms, the heating equipment is immediately activated to heat the produced fluid. The power and heating time of the heating equipment can be adjusted through the control components to ensure that the temperature of the produced fluid is stably maintained above the minimum temperature at which wax easily forms, thereby achieving the purpose of preventing and removing wax.

[0150] Furthermore, the minimum temperature at which the extracted fluid is prone to wax deposition is set at 60–65°C.

[0151] Furthermore, when the wax deposition in the produced fluid is severe, chemical agents can be injected into the heating equipment through the injection switch to remove the paraffin wax from the produced fluid and further prevent wax deposition, thus achieving the purpose of wax removal and prevention.

[0152] Specifically, chemical agents may include mixed benzene, light oil, alcohol ethers and other organic solvents.

[0153] By implementing this step, we can effectively prevent wax formation caused by low temperatures, maintain the fluidity and stability of the extracted fluid, and reduce pipeline blockage and maintenance costs caused by wax formation.

[0154] To better understand the anti-condensation method of the present invention, the following is in conjunction with the appendix. Figure 1The specific implementation steps for anti-condensation operations are further explained.

[0155] The specific implementation steps of the present invention for anti-condensation operations may include:

[0156] (1) The fluid at the bottom of the well flows through the tubing in the wellbore to the wellhead on the surface and forms produced fluid. The produced fluid enters the anti-condensation device through the inlet valve.

[0157] (2) The extracted fluid enters the heating equipment through the inlet insulation short section. The temperature detector and pressure detector can detect the temperature and pressure of the extracted fluid in real time and transmit the temperature value to the control component and the pressure value to the ring pressure control component.

[0158] (3) If the temperature detector detects that the temperature of the extracted fluid is too low (generally lower than the minimum temperature T at which the fluid is prone to waxing, and T is generally set at 60-65℃), the control component will adjust the switch to make the electric heating grid inside the heating equipment heat up, thereby increasing the temperature of the extracted fluid and achieving the purpose of preventing and removing wax; when the temperature of the extracted fluid can reach T, the adjustment switch will automatically cut off the power and stop heating.

[0159] (4) The produced fluid enters the pressure control device through the outlet insulation short section. The ring pressure control component on the pressure control device controls the pressure of the ring pressure rubber ring to maintain the pressure at the preset pressure value P1. The setting of P1 should not be less than (greater than or equal to) the wellhead pressure value corresponding to the gas phase at the bottom of the well when condensation is about to occur. That is, P1 should be greater than or equal to the minimum pressure value at the reverse condensation wellhead.

[0160] (5) If the pressure of the ring is lower than P1, the ring pressure control component will automatically inject pressurized fluid into the ring so that the pressure of the ring is always stable at the P1 level.

[0161] (6) The annular pressure control device also receives the wellhead pressure value P2 of the produced fluid transmitted by the pressure detector. The annular pressure control device can adjust the level of P1 appropriately according to the value of P2. If P2 is greater than P1, the produced fluid passes through the pressure control device normally. If P2 is not greater than (less than or equal to) P1, the annular pressure ring expands and fills the fluid channel of the pressure control device, and the produced fluid is temporarily slowed to pass through, so that the pressure inside the well begins to build up, thereby controlling the bottom pressure and achieving the purpose of reverse condensation.

[0162] (7) When P2 is not greater than P1, the well begins to pressurize and control the bottom fluid to carry out reverse condensation. At the same time, if the temperature detector detects that the temperature of the produced fluid is too low, the control component controls the heating equipment to start heating through the adjustment switch to prevent the produced fluid from condensing and blocking the device. It also plays the role of clearing wax. When the temperature of the produced fluid reaches T, the adjustment switch automatically cuts off the power and stops heating, the same as step (3).

[0163] (8) If the produced fluid in the anti-condensation unit is severely waxed, or if it is necessary to add chemical agents to control / prevent waxing of the produced fluid, chemical agents can be added to the produced fluid in the heating equipment through the filling switch of the control component to control / prevent waxing of the produced fluid.

[0164] (9) The produced fluid flows into the auxiliary pressurization equipment through the one-way short section until it flows out of the outlet valve and the outlet device. The one-way short section is mainly to prevent the fluid from flowing back. The auxiliary pressurization equipment is mainly to further increase the pressure of the produced fluid so that the fluid can smoothly enter the pipeline network for collection and transportation.

[0165] Example 7

[0166] This invention uses fluid from a condensate oil and gas reservoir in the Sichuan Basin as the injection fluid and conducts experiments on a reverse condensate device.

[0167] The operating condition involves injecting the fluid from the inlet of the reverse condensation unit, with four different temperatures and pressures set for the injected fluid, corresponding to four different wellhead pressure and temperature values ​​for the produced fluid:

[0168] ① Injected fluid pressure > P1, injected fluid temperature > T;

[0169] ②Injected fluid pressure > P1, injected fluid temperature < T;

[0170] ③ Injected fluid pressure < P1, injected fluid temperature > T;

[0171] ④ The injection fluid pressure is less than P1 and the injection fluid temperature is less than T.

[0172] The lowest temperature at which the injected fluid is prone to wax formation is set to T. In the experiment, the preset pressure value of the ring pressure rubber ring is set to P1 and kept stable by the ring pressure control device.

[0173] Experimental results show that:

[0174] Option 1: The heating equipment of the anti-condensation unit was not started, and the pressure control equipment was not closed to the fluid channel, meaning that the injected fluid was not heated and passed through the unit smoothly;

[0175] Option 2: The heating equipment of the anti-condensation unit is started, the pressure control equipment does not close the fluid channel, that is, the injected fluid is heated and passes through the unit smoothly, and the heating equipment stops heating when the temperature of the injected fluid reaches T;

[0176] Option 3: The heating equipment of the anti-condensation unit is not started, and the pressure control equipment closes the fluid channel. That is, the injected fluid is not heated and the unit is closed, forming a pressure buildup. When the injected fluid pressure reaches P1, the fluid channel of the pressure control equipment opens and the fluid passes through the unit smoothly.

[0177] Option 4: The heating equipment of the anti-condensation unit starts heating, and the pressure control equipment closes the fluid channel. That is, the injected fluid is heated and the unit is closed to form pressure. When the injected fluid pressure reaches P1 and the temperature reaches T, the fluid channel of the pressure control equipment opens, the fluid passes smoothly through the unit, and the heating equipment stops heating. See Table 1 for details.

[0178] Table 1 Comparison of Experimental Design Conditions and Effects

[0179]

[0180] The above experiments demonstrate that the anti-condensation device can detect and control the temperature and pressure of the produced fluid in real time. When the produced fluid pressure is low, the anti-condensation device can temporarily slow the flow of the produced fluid through the annular pressure device, causing pressure buildup in the well to control the bottom hole pressure and achieve the purpose of anti-condensation. When the produced fluid temperature is low, the anti-condensation device can heat the produced fluid through the heating device to increase the temperature of the produced fluid, thereby achieving the purpose of preventing and removing wax.

[0181] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A reverse condensation apparatus, characterized in that, The anti-condensation device is installed at the wellhead and connected to the tubing in the wellbore. It includes a pressure control device with a fluid channel. The fluid channel is used for the produced fluid in the tubing to flow outward. The fluid channel is equipped with a control component fixed to the inner wall of the channel. The control component is filled with pressurized fluid and its pressure is maintained at a preset pressure value. The control component can expand and close the fluid channel when the wellhead pressure of the produced fluid is not greater than the preset pressure value, so as to create pressure buildup in the well and prevent the pressure in the well from dropping to the point of condensation. The control component is a ring-shaped pressure ring. The outer ring of the ring-shaped pressure ring is fixedly installed on the inner wall of the fluid channel. The ring body of the ring-shaped pressure ring is filled with the pressurized fluid, and the ring-shaped pressure ring can expand its inner ring towards the center and close under the pressure of the pressurized fluid to seal the fluid channel.

2. The anti-condensation apparatus according to claim 1, characterized in that, The ring pressure ring is connected to a ring pressure control component, which is used to inject the pressure fluid into the ring pressure ring and can maintain the pressure of the pressure fluid in the ring pressure ring at the preset pressure value.

3. The anti-condensation apparatus according to claim 2, characterized in that, The pressure control device is equipped with a pressure detector at the inlet end to detect the wellhead pressure of the produced fluid. The pressure detector is electrically connected to the annular pressure control component, which can adjust the preset pressure value according to the wellhead pressure value detected by the pressure detector.

4. The anti-condensation apparatus according to claim 1, characterized in that, The anti-condensation device also includes a heating device, which is connected in sequence with the pressure control device in the flow direction of the produced fluid. The heating device can increase the temperature of the produced fluid.

5. The anti-condensation apparatus according to claim 4, characterized in that, The heating device is equipped with a control component and a temperature detector. The temperature detector is electrically connected to the control component, and the control component can control the heating device to heat the extracted fluid based on the temperature information detected by the temperature detector.

6. A method for reverse condensation, characterized in that, The apparatus used in any one of claims 1 to 5 comprises at least the following steps: The pressure control components of the pressure control device in the anti-condensation apparatus are filled with pressurized fluid and the pressure is maintained at a preset pressure value. When the wellhead pressure value of the produced fluid reaches the wellhead is not greater than the preset pressure value, the control component closes the fluid channel of the pressure control device to block the outflow of the produced fluid and create pressure buildup in the well, thus preventing the wellhead pressure from dropping to the point of condensation.

7. The anti-condensation method according to claim 6, characterized in that, The preset pressure value is not less than the critical wellhead pressure value corresponding to the point when condensation is about to occur in the gas phase at the bottom of the well.

8. The anti-condensation method according to claim 7, characterized in that, The anti-condensation method further includes the following steps: The wellhead temperature of the produced fluid is detected by a temperature detector. When the wellhead temperature is lower than the minimum temperature at which wax easily forms, the heating equipment is turned on to heat the produced fluid.

9. A reverse condensation system, characterized in that, The anti-condensation system includes an anti-condensation device as described in any one of claims 1 to 5 and a software control center, wherein the software control center is electrically connected to the anti-condensation device and is capable of controlling the anti-condensation device to operate according to a preset logic control program.

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