Reverse condensation device, method and system

Abstract

The invention provides a reverse condensation device, method and system.The reverse condensation device is arranged at a wellhead and connected with a pipe column in a shaft and comprises a pressure control device provided with a fluid channel, the fluid channel is used for outward circulation of produced fluid in the pipe column, and a control component fixed to the inner wall of the channel is arranged in the fluid channel; the control part is filled with pressure fluid, and the pressure of the control part is maintained at a preset pressure value. The reverse condensation method is applied to the reverse condensation device. The reverse condensation system comprises the reverse condensation device and a software control center. The device has the beneficial effects that the control component of the pressure control equipment is used for blocking the produced fluid, so that pressure building is started in a well, the bottom hole pressure is further controlled, and the purpose of reverse condensation is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and in particular to a reverse condensation device, method and system suitable for condensate oil and gas reservoirs. Background Art

[0002] Condensate refers to the process by which hydrocarbon gases, after being extracted from deep underground under high-temperature and high-pressure conditions, change from a gaseous state to a liquid state due to a decrease in temperature and pressure. This liquid, light oil is called condensate, and this type of reservoir is called a condensate reservoir, a type of reservoir between oil and gas. Condensate reservoirs are generally developed using a depletion-based development process. However, in the middle and late stages of depletion-based development, reservoir energy is insufficient and formation pressure falls below the dew point, making condensate contamination more likely to occur. This results in the formation of large amounts of condensate in the reservoir near the wellbore. Due to its difficulty in flowing, the condensate is retained in the reservoir near the wellbore, directly leading to a sharp decrease in reservoir permeability, obstructed gas flow in areas farther from the wellbore, reduced single-well productivity, a rapid decline in oil and gas production, and a reduction in reservoir recovery.

[0003] Currently, the common methods of retrograde condensation are: first, to reasonably adjust the production layer, optimize the well network, well spacing and well type, and reasonably adjust the production system of oil and gas wells; second, to supplement the reservoir energy and use chemical and engineering methods, such as gas injection, methanol injection, mutual solvent injection, steam injection, reservoir heating, repeated fracturing and other measures.

[0004] In the practical application of existing technologies, when condensate contamination has already occurred, methods and measures such as injecting chemical reagents and repeated fracturing are proposed to eliminate condensate contamination. From the perspective of early prevention, there are few integrated prevention-control methods or devices for retrograde condensation control. There is even less research on preventing retrograde condensation by controlling the production system at the wellhead.

[0005] Therefore, it is necessary to study a wellhead prevention-control integrated retrograde condensation device, method and system to solve the above problems or alleviate the impact of the above problems. Summary of the Invention

[0006] On one hand, the present invention provides a reverse condensation device, which blocks the produced fluid through the control component of the pressure control equipment, causing the well to begin to build up pressure, thereby controlling the bottom hole pressure and achieving the purpose of reverse condensation, thereby effectively solving or alleviating the above-mentioned technical problems.

[0007] The reverse condensation device of the present invention is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device with a fluid channel, the fluid channel is used to circulate the produced fluid in the tubing string outward, and the fluid channel is provided with a control component fixed to the inner wall of the channel, the control component is filled with pressure fluid and its pressure is maintained at a preset pressure value;

[0008] The control component can expand and close the fluid channel when the wellhead pressure value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

[0009] In one embodiment, the control component is a ring-pressed rubber ring, the outer ring of which is fixedly laid on the inner wall of the fluid channel, the ring body of which is filled with the pressure fluid, and the inner ring of which can expand toward the center and close under the pressure of the pressure fluid to seal the fluid channel.

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

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

[0012] In one embodiment, the reverse condensation device further includes a heating device, and the heating device and the pressure control device are sequentially connected in the flow direction of the produced fluid, and the heating device can increase the temperature of the produced fluid.

[0013] In one embodiment, the heating device is provided 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 produced fluid according to the temperature information detected by the temperature detector.

[0014] Another aspect of the present invention provides a reverse condensation method, which is applied to the reverse condensation device as described above and comprises at least the following steps:

[0015] Filling a control component of a pressure control device in the reverse condensation device with pressure fluid and maintaining the pressure at a preset pressure value;

[0016] The control component closes the fluid channel of the pressure control device when the wellhead pressure value of the produced fluid reaching the wellhead is not greater than the preset pressure value, so as to block the outflow of the produced fluid and form a pressure buildup in the well, thereby preventing the pressure in the well from being reduced to the point where condensation occurs.

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

[0018] In one embodiment, the reverse condensation method further comprises the steps of:

[0019] The wellhead temperature value of the produced fluid when it reaches the wellhead is detected by a temperature detector. When the wellhead temperature value is lower than the lowest temperature at which wax is easily formed, the heating device is turned on to heat the produced fluid.

[0020] On the other hand, the present invention provides a reverse condensation system, which includes the reverse condensation device as described above and a software control center, wherein the software control center is electrically connected to the reverse condensation device, and the software control center can control the reverse condensation device to operate according to a preset logic control program.

[0021] The reverse condensation device provided by the present invention has at least the following beneficial effects compared with the prior art:

[0022] The reverse condensation device of the present invention can block the produced fluid through the control components of the pressure control equipment when the pressure of the produced fluid reaching the wellhead is low, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. In this way, by setting up a reasonable mining and production system, the reverse condensation device can be used to prevent and control the occurrence of condensation pollution, thereby ensuring the production capacity and recovery rate of oil and gas reservoirs.

[0023] The reverse condensation method provided by the present invention also has the above-mentioned beneficial effects because it is applied to the above-mentioned reverse condensation device.

[0024] A reverse condensation system provided by the present invention also has the above-mentioned beneficial effects because it includes the above-mentioned reverse condensation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Hereinafter, the present invention will be described in more detail based on embodiments with reference to the accompanying drawings.

[0026] Figure 1 It is a structural schematic diagram of a reverse condensation device according to an embodiment of the present invention.

[0027] In the drawings, like reference numerals are used for like parts, but the drawings are not necessarily drawn to scale.

[0028] Reference numerals:

[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 insulation short section, 9-outlet insulation short section, 10-one-way short section, 11-auxiliary boosting equipment, 12-inlet valve, 13-outlet valve. DETAILED DESCRIPTION

[0030] The existing methods for solving the condensation pollution phenomenon include:

[0031] Tang Kai et al. designed an experimental apparatus and method for simulating liquid-phase damage and its resolution 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 back-pressure valve. The apparatus simulated the combined liquid-phase damage of reverse condensation and water lock by reverse water injection in long cores after retrograde condensation damage, and also reversely injected plugging agent into the long cores after the combined liquid-phase damage, then soaked and reinstated the well to resolve the liquid-phase damage. Multiple permeabilities were obtained at different stages to evaluate the extent of liquid-phase damage and the effectiveness of the repair. Clearly, this method primarily serves as a reservoir damage assessment method, and simply proposes a plugging agent injection method for retrograde condensation reservoirs.

[0032] Wang Xinyu and his colleagues devised a method for removing near-wellbore retrograde condensate contamination by huff-and-puff gas injection in condensate gas wells. First, they selected a condensate gas well clogged with retrograde condensate, shut it in, and cleared the fluid from the wellbore. Then, they converted the production well into a gas injection well and injected natural gas that had been deoiled, dehydrated, and treated for impurities. After the injection, they shut the well and observed changes in wellhead pressure. If the pressure approached the shut-in pressure before injection, it indicated that the injected gas had diffused into distant formations, and normal production could be resumed. This method clearly demonstrates a method for removing retrograde condensate contamination through gas injection.

[0033] Wu Zhijun et al. designed a method for rapidly decontaminating condensate gas reservoirs. This method involves first injecting nitrogen into the reservoir, then injecting ethanol, and then continuing with nitrogen injection, then shutting the well and draining the reservoir. This method, however, only proposes a chemical reagent injection method for decontaminating condensate gas reservoirs after condensate contamination has already occurred.

[0034] Wang Moran et al. designed a method for suppressing retrograde condensation in condensate gas reservoirs. They first monitor well gas production and reservoir parameters at pre-set intervals. Based on these rates and reservoir parameters, a predetermined algorithm is used to determine the power of a heating resistor. The heating resistor is pre-installed in the well casing or along the oil pipeline cable. Finally, the actual power of the heating resistor is adjusted based on the determined power, achieving the goal of suppressing retrograde condensation in condensate gas reservoirs through heating. This method is primarily used for wellbore heating to induce retrograde condensation.

[0035] Zhang Chong et al. designed a method and system for decontaminating the retrograde condensate zone. They first side-drilled the target well casing along a predetermined direction within the target reservoir. They then fractured the original artificial fractures to create new ones. A carrier fluid carrying a plugging agent was then injected into the new fractures to temporarily plug them. Finally, the side-drilled retrograde condensate zone was fractured again to form a fracture system, ultimately decontaminating the entire retrograde condensate zone. Clearly, this method simply proposes a method similar to repeated fracturing to decontaminate the entire retrograde condensate zone.

[0036] In summary, the current method for retrograde condensation in condensate oil and gas reservoirs is mainly to supplement formation energy and adopt chemical and fracturing methods such as gas injection, methanol injection, and repeated fracturing when condensate contamination has already occurred. However, the reduction in energy of condensate oil and gas reservoirs is largely due to unreasonable production systems. Few retrograde condensation control methods and devices that integrate prevention and control from the perspective of early prevention are proposed, and there is even a lack of prevention of retrograde condensation from the perspective of controlling production systems at the wellhead. Therefore, the retrograde condensation device, method, and system with integrated wellhead prevention and control proposed in the present invention are of great significance.

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

[0038] Example 1

[0039] like Figure 1 As shown, the reverse condensation device of the present invention is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device 1 with a fluid channel, the fluid channel is used to circulate the produced fluid in the tubing string outward, and the fluid channel is provided with a control component 2 fixed to the inner wall of the channel, and the control component 2 is filled with pressure fluid and its pressure is maintained at a preset pressure value;

[0040] The control component 2 can expand and close the fluid channel when the wellhead pressure value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

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

[0042] The pressure control device 1 is equipped with a control component 2 at a key location in the fluid channel. The control component 2 is fixed to the inner wall of the fluid channel and is filled with a specific pressure fluid, and the pressure of the pressure fluid is controlled at a preset pressure value. This allows the control component 2 to expand and contract due to the pressure difference between the internal pressure fluid and the external produced 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 value 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 pressure fluid in the control component 2, the produced fluid cannot squeeze the control component 2 to make the fluid channel unobstructed. Instead, the control component 2 expands and fills the entire fluid channel to form a seal, thereby 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 starts to suppress pressure from the wellhead into the well, thereby reacting to the bottom of the well, causing the formation pressure at the bottom of the well to increase. This can avoid condensation contamination caused by the decrease in formation pressure at the bottom of the well, thereby achieving the purpose of reverse condensation.

[0045] Generally speaking, the reverse condensation device can block the flow of produced fluid through the control component 2 of the pressure control device 1 when the pressure of the produced fluid reaching the wellhead is low, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. In this way, by establishing a reasonable mining and production system and using the reverse condensation device, the occurrence of condensation pollution can be prevented and controlled, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0046] Example 2

[0047] like Figure 1 As shown, the reverse condensation device of the present invention is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device 1 with a fluid channel, the fluid channel is used to circulate the produced fluid in the tubing string outward, and the fluid channel is provided with a control component 2 fixed to the inner wall of the channel, and the control component 2 is filled with pressure fluid and its pressure is maintained at a preset pressure value;

[0048] The control component 2 can expand and close the fluid channel when the wellhead pressure value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

[0049] Generally speaking, the reverse condensation device can block the flow of produced fluid through the control component 2 of the pressure control device 1 when the pressure of the produced fluid reaching the wellhead is low, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. In this way, by establishing a reasonable mining and production system and using the reverse condensation device, the occurrence of condensation pollution can be prevented and controlled, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

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

[0051] Specifically, the ring-shaped rubber ring is annular and made of an elastic material. The outer ring of the ring-shaped rubber ring is fixed to the inner wall of the fluid channel and sealed with the inner wall, i.e., there is no gap between the outer ring and the inner wall for the produced fluid to pass through. The inner ring of the ring-shaped rubber ring forms a channel for the produced fluid to flow through. The interior of the ring-shaped rubber ring is filled with pressurized fluid. The presence of the pressurized fluid enables the ring-shaped rubber ring to respond quickly when there is a pressure difference between the internal pressure of the ring and the external pressure.

[0052] In this way, when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid can squeeze the annular pressure rubber ring to make the fluid channel unobstructed; when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid cannot squeeze the annular pressure rubber ring to make the fluid channel unobstructed, but the annular body of the annular pressure rubber ring expands, causing its inner ring to squeeze toward the center and then fill the entire fluid channel to form a closure, thereby blocking the produced fluid from flowing out.

[0053] Obviously, the outer ring of the ring-type rubber ring is fixedly attached to the inner wall of the fluid channel, serving as the fixed connection end of the ring-type rubber ring and ensuring its stability and reliability during operation. The inner ring of the ring-type rubber ring can expand and contract under the pressure of the fluid within the ring body, and is the functional part that blocks or clears the fluid channel, enabling rapid response and control to ensure that the fluid channel can be effectively sealed when needed.

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

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

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

[0057] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure rubber ring. Through advanced control technology and precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure rubber ring in real time by injecting or discharging pressure fluid to ensure that it always maintains the preset pressure value. This function is crucial to ensure the normal operation of the reverse condensation device. It can discharge the pressure fluid in the ring pressure rubber ring when the pressure of the produced fluid is high, and the ring pressure rubber ring shrinks to make the fluid channel of the pressure control device 1 unobstructed; it can inject pressure fluid into the ring pressure rubber ring when the pressure of the produced fluid is low, and the ring pressure rubber ring expands to close the fluid channel of the pressure control device 1.

[0058] In one example, the inlet end of the pressure control device 1 is provided with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the ring pressure control component 3. The ring 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, can accurately capture the dynamic changes of the wellhead pressure, and transmit relevant data.

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

[0061] In this way, at different stages of oil and gas production, the preset pressure value is adjusted and controlled according to the attenuation degree of the oil and gas reservoir formation pressure and the change in the wellhead pressure of the produced fluid reaching the wellhead to match the designed reasonable production system, prevent and control the occurrence of condensate 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 reverse condensation device of the present invention is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device 1 with a fluid channel, the fluid channel is used to circulate the produced fluid in the tubing string outward, and the fluid channel is provided with a control component 2 fixed to the inner wall of the channel, and the control component 2 is filled with pressure fluid and its pressure is maintained at a preset pressure value;

[0064] The control component 2 can expand and close the fluid channel when the wellhead pressure value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

[0065] Generally speaking, the reverse condensation device can block the flow of produced fluid through the control component 2 of the pressure control device 1 when the pressure of the produced fluid reaching the wellhead is low, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. In this way, by establishing a reasonable mining and production system and using the reverse condensation device, the occurrence of condensation pollution can be prevented and controlled, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

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

[0067] Specifically, the ring-shaped rubber ring is annular and made of an elastic material. The outer ring of the ring-shaped rubber ring is fixed to the inner wall of the fluid channel and sealed with the inner wall, i.e., there is no gap between the outer ring and the inner wall for the produced fluid to pass through. The inner ring of the ring-shaped rubber ring forms a channel for the produced fluid to flow through. The interior of the ring-shaped rubber ring is filled with pressurized fluid. The presence of the pressurized fluid enables the ring-shaped rubber ring to respond quickly when there is a pressure difference between the internal pressure of the ring and the external pressure.

[0068] In this way, when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid can squeeze the annular pressure rubber ring to make the fluid channel unobstructed; when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid cannot squeeze the annular pressure rubber ring to make the fluid channel unobstructed, but the annular body of the annular pressure rubber ring expands, causing its inner ring to squeeze toward the center and then fill the entire fluid channel to form a closure, thereby blocking the produced fluid from flowing out.

[0069] Obviously, the outer ring of the ring-type rubber ring is fixedly attached to the inner wall of the fluid channel, serving as the fixed connection end of the ring-type rubber ring and ensuring its stability and reliability during operation. The inner ring of the ring-type rubber ring can expand and contract under the pressure of the fluid within the ring body, and is the functional part that blocks or clears the fluid channel, enabling rapid response and control to ensure that the fluid channel can be effectively sealed when needed.

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

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

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

[0073] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure rubber ring. Through advanced control technology and precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure rubber ring in real time by injecting or discharging pressure fluid to ensure that it always maintains the preset pressure value. This function is crucial to ensure the normal operation of the reverse condensation device. It can discharge the pressure fluid in the ring pressure rubber ring when the pressure of the produced fluid is high, and the ring pressure rubber ring shrinks to make the fluid channel of the pressure control device 1 unobstructed; it can inject pressure fluid into the ring pressure rubber ring when the pressure of the produced fluid is low, and the ring pressure rubber ring expands to close the fluid channel of the pressure control device 1.

[0074] In one example, the inlet end of the pressure control device 1 is provided with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the ring pressure control component 3. The ring 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, can accurately capture the dynamic changes of the wellhead pressure, and transmit relevant data.

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

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

[0078] In one example, Figure 1As shown, the reverse condensation device further includes a heating device 5, which is connected in sequence with the pressure control device 1 in the flow direction of the produced fluid. The heating device 5 can increase the temperature of the produced fluid.

[0079] Specifically, the inlet end of the heating device 5 is connected to the tubing in 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 reverse condensation device can heat the produced fluid through the heating device 5 to increase the temperature of the produced fluid, thereby preventing the produced fluid from waxing due to low temperature, and has the functions of preventing and removing wax.

[0081] Furthermore, the coordinated operation of the heating device 5 and the pressure control device 1 can significantly enhance the overall performance of the reverse condensation unit. Maintaining the temperature of the produced fluid through heating can beneficially alter its physical properties, such as reducing viscosity and enhancing fluidity. This helps the produced fluid flow more smoothly through the 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 arranged on the heating device 5 to detect the wellhead pressure value of the produced fluid at the inlet end of the pressure control device 1 .

[0083] In one example, the heating device 5 is provided with a control component 6 and a temperature detector 7. The temperature detector 7 is electrically connected to the control component 6. The control component 6 can control the heating device 5 to heat the produced fluid according to 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 precision, and has real-time monitoring and certain data analysis functions. It can accurately capture the dynamic changes of the wellhead temperature and transmit relevant data.

[0085] The temperature detector 7 and the control component 6 are electrically connected to form 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 on or off heating according to 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 low (generally lower than the lowest temperature at which the produced fluid is prone to wax formation), the control component 6 controls the heating device 5 to turn on and heat the produced fluid, thereby raising the temperature of the produced fluid and preventing and removing wax from the produced fluid. When the temperature of the produced fluid rises (reaches the lowest temperature at which the produced fluid is prone to wax formation) and stabilizes, the control component 6 controls the heating device 5 to turn off and stop heating.

[0087] Furthermore, an electric heating network is provided inside the heating device 5 , and the control component 6 includes an adjustment switch, which can control and adjust the heating power and switch of the electric heating network.

[0088] Specifically, temperature detector 7 monitors the temperature of the produced fluid in real time and transmits this information to control component 6. Based on this received temperature information, control component 6 intelligently determines whether to turn the electric heating network on or off or adjust its heating power. Thus, through precise control of the control component 6's regulating switch, heating device 5 ensures that the produced fluid temperature is always maintained within the ideal range, preventing wax formation caused by excessively low temperatures and avoiding potential safety risks caused by excessively high temperatures.

[0089] Example 4

[0090] like Figure 1 As shown, the reverse condensation device of the present invention is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device 1 with a fluid channel, the fluid channel is used to circulate the produced fluid in the tubing string outward, and the fluid channel is provided with a control component 2 fixed to the inner wall of the channel, and the control component 2 is filled with pressure fluid and its pressure is maintained at a preset pressure value;

[0091] The control component 2 can expand and close the fluid channel when the wellhead pressure value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

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

[0093] The pressure control device 1 is equipped with a control component 2 at a key location in the fluid channel. The control component 2 is fixed to the inner wall of the fluid channel and is filled with a specific pressure fluid, and the pressure of the pressure fluid is controlled at a preset pressure value. This allows the control component 2 to expand and contract due to the pressure difference between the internal pressure fluid and the external produced 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 value 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 pressure fluid in the control component 2, the produced fluid cannot squeeze the control component 2 to make the fluid channel unobstructed. Instead, the control component 2 expands and fills the entire fluid channel to form a seal, thereby 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 starts to suppress pressure from the wellhead into the well, thereby reacting to the bottom of the well, causing the formation pressure at the bottom of the well to increase. This can avoid condensation contamination caused by the decrease in formation pressure at the bottom of the well, thereby achieving the purpose of reverse condensation.

[0096] Generally speaking, the reverse condensation device can block the flow of produced fluid through the control component 2 of the pressure control device 1 when the pressure of the produced fluid reaching the wellhead is low, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. In this way, by establishing a reasonable mining and production system and using the reverse condensation device, the occurrence of condensation pollution can be prevented and controlled, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

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

[0098] Specifically, the ring-shaped rubber ring is annular and made of an elastic material. The outer ring of the ring-shaped rubber ring is fixed to the inner wall of the fluid channel and sealed with the inner wall, i.e., there is no gap between the outer ring and the inner wall for the produced fluid to pass through. The inner ring of the ring-shaped rubber ring forms a channel for the produced fluid to flow through. The interior of the ring-shaped rubber ring is filled with pressurized fluid. The presence of the pressurized fluid enables the ring-shaped rubber ring to respond quickly when there is a pressure difference between the internal pressure of the ring and the external pressure.

[0099] In this way, when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid can squeeze the annular pressure rubber ring to make the fluid channel unobstructed; when the wellhead pressure value of the produced fluid flowing into the pressure control device 1 is not greater than the preset pressure value of the pressure fluid in the annular pressure rubber ring, the produced fluid cannot squeeze the annular pressure rubber ring to make the fluid channel unobstructed, but the annular body of the annular pressure rubber ring expands, causing its inner ring to squeeze toward the center and then fill the entire fluid channel to form a closure, thereby blocking the produced fluid from flowing out.

[0100] Obviously, the outer ring of the ring-type rubber ring is fixedly attached to the inner wall of the fluid channel, serving as the fixed connection end of the ring-type rubber ring and ensuring its stability and reliability during operation. The inner ring of the ring-type rubber ring can expand and contract under the pressure of the fluid within the ring body, and is the functional part that blocks or clears the fluid channel, enabling rapid response and control to ensure that the fluid channel can be effectively sealed when needed.

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

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

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

[0104] More importantly, the ring pressure control component 3 also has the function of maintaining the pressure of the ring pressure rubber ring. Through advanced control technology and precise adjustment mechanism, the ring pressure control component 3 can adjust the pressure of the ring pressure rubber ring in real time by injecting or discharging pressure fluid to ensure that it always maintains the preset pressure value. This function is crucial to ensure the normal operation of the reverse condensation device. It can discharge the pressure fluid in the ring pressure rubber ring when the pressure of the produced fluid is high, and the ring pressure rubber ring shrinks to make the fluid channel of the pressure control device 1 unobstructed; it can inject pressure fluid into the ring pressure rubber ring when the pressure of the produced fluid is low, and the ring pressure rubber ring expands to close the fluid channel of the pressure control device 1.

[0105] In one example, the inlet end of the pressure control device 1 is provided with a pressure detector 4 for detecting the wellhead pressure of the produced fluid. The pressure detector 4 is electrically connected to the ring pressure control component 3. The ring 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, can accurately capture the dynamic changes of the wellhead pressure, and transmit relevant data.

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

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

[0109] In one example, Figure 1 As shown, the reverse condensation device further includes a heating device 5, which is connected in sequence with the pressure control device 1 in the flow direction of the produced fluid. The heating device 5 can increase the temperature of the produced fluid.

[0110] Specifically, the inlet end of the heating device 5 is connected to the tubing in 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 reverse condensation device can heat the produced fluid through the heating device 5 to increase the temperature of the produced fluid, thereby preventing the produced fluid from waxing due to low temperature, and has the functions of preventing and removing wax.

[0112] Furthermore, the coordinated operation of the heating device 5 and the pressure control device 1 can significantly enhance the overall performance of the reverse condensation unit. Maintaining the temperature of the produced fluid through heating can beneficially alter its physical properties, such as reducing viscosity and enhancing fluidity. This helps the produced fluid flow more smoothly through the 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 arranged on the heating device 5 to detect the wellhead pressure value of the produced fluid at the inlet end of the pressure control device 1 .

[0114] In one example, the heating device 5 is provided with a control component 6 and a temperature detector 7. The temperature detector 7 is electrically connected to the control component 6. The control component 6 can control the heating device 5 to heat the produced fluid according to 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 precision, and has real-time monitoring and certain data analysis functions. It can accurately capture the dynamic changes of the wellhead temperature and transmit relevant data.

[0116] The temperature detector 7 and the control component 6 are electrically connected to form 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 on or off heating according to 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 low (generally lower than the lowest temperature at which the produced fluid is prone to wax formation), the control component 6 controls the heating device 5 to turn on and heat the produced fluid, thereby raising the temperature of the produced fluid and preventing and removing wax from the produced fluid. When the temperature of the produced fluid rises (reaches the lowest temperature at which the produced fluid is prone to wax formation) and stabilizes, the control component 6 controls the heating device 5 to turn off and stop heating.

[0118] Furthermore, an electric heating network is provided inside the heating device 5 , and the control component 6 includes an adjustment switch, which can control and adjust the heating power and switch of the electric heating network.

[0119] Specifically, temperature detector 7 monitors the temperature of the produced fluid in real time and transmits this information to control component 6. Based on this received temperature information, control component 6 intelligently determines whether to turn the electric heating network on or off or adjust its heating power. Thus, through precise control of the control component 6's regulating switch, heating device 5 ensures that the produced fluid temperature is always maintained within the ideal range, preventing wax formation caused by excessively low temperatures and avoiding potential safety risks caused by excessively high temperatures.

[0120] In one example, the control component 6 further includes a filling switch provided on the heating device 5 , and the filling switch is used to fill chemical agents into the heating device 5 .

[0121] Specifically, if the wax deposition in the produced fluid is serious, the fluidity of the produced fluid will be low, and it will be easy to form a blockage when it is subsequently transported outward through the pressure control device 1. In this way, chemical agents can be added to the heating device 5 through the filling switch to remove the paraffin in the produced fluid, and it can also further prevent wax deposition, thereby achieving the purpose of wax removal and wax prevention.

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

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

[0124] Specifically, an inlet insulation subsection 8 and an outlet insulation subsection 9 are provided at the front and rear ends of the heating device 5, respectively. These not only insulate the heating device 5 from the upstream pipeline and the downstream pressure control device 1, preventing possible current leakage, but also provide certain buffering and vibration reduction functions, reducing the impact and vibration generated by the produced fluid when entering 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 10 is installed at the rear end of the pressure control device 1. Its primary function is to prevent backflow of produced fluid at the rear end of the pressure control device 1. In certain situations, due to pressure fluctuations or other factors, fluid backflow may occur, which can affect the normal operation of the pressure control device 1 or even cause damage to the device. The design of the one-way sub 10 effectively solves this problem by only allowing produced fluid to flow downstream from the pressure control device 1, preventing backflow and thus ensuring the stable operation of the pressure control device 1.

[0126] In this way, the reverse condensation device can improve the operating efficiency and safety of the reverse condensation device, enhance the stability and durability of the device operation, and reduce the failure rate and maintenance cost by configuring the inlet insulation short section 8, the outlet insulation short section 9 and the one-way short section 10.

[0127] In one example, the reverse condensation device further includes an auxiliary pressure-boosting device 11 connected to the rear end of the pressure-control device 1 , and the auxiliary pressure-boosting device 11 can increase the pressure of the produced fluid.

[0128] Specifically, the produced fluid flowing out of the pressure control device 1 flows through the one-way short joint 10 into the auxiliary boosting device 11, and then flows to the pipeline network after being pressurized by the auxiliary boosting device 11. The main function of the auxiliary boosting device 11 is to further increase the pressure of the produced fluid so that the produced fluid can smoothly enter the pipeline network for collection and transportation.

[0129] In one example, the reverse condensation device further includes an inlet valve 12 disposed before the inlet insulating sub 8 and an outlet valve 13 disposed after the auxiliary pressurizing device 11 .

[0130] Specifically, the inlet valve 12 is located at the front end of the reverse condensation device, and plays the role of controlling the entry of the produced fluid into the device. In addition, when shutdown maintenance or emergency situations are required, the inlet valve 12 can be quickly closed to cut off the entry of the produced fluid into the device, thereby 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 the event of shutdown or emergency, the outlet valve 13 can be quickly closed to stop the produced fluid from continuing to flow out of the device, preventing possible leakage and accidents.

[0132] In this way, the addition of the inlet valve 12 and the outlet valve 13 can not only improve the operational flexibility of the reverse condensation device, but also enhance its safety. In an emergency, the fluid can be quickly cut off to prevent the accident from expanding and protect the safety of equipment and personnel.

[0133] In summary, the reverse 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 reverse condensation device can temporarily suspend the passage of the produced fluid through the pressure control device 1, causing the well to begin to build up pressure, thereby controlling the bottom hole pressure and achieving the purpose of reverse condensation; when the produced fluid temperature is low, the reverse condensation device can heat the produced fluid through the heating device 5 to increase the temperature of the produced fluid, thereby achieving the purpose of preventing and removing wax; the reverse condensation device can also add chemical agents to the produced fluid as needed to control and prevent wax formation in the fluid, and can also further increase the pressure of the produced fluid through the auxiliary boosting device 11, so that the produced fluid can smoothly enter the pipeline network for collection and transportation.

[0134] Example 5

[0135] The reverse condensation system of the present invention comprises the aforementioned reverse condensation device and a software control center. The software control center is electrically connected to the reverse condensation device and can control the reverse condensation device to operate according to a preset logic control program.

[0136] Specifically, the retrograde condensation system of the present invention mainly includes two core parts: the retrograde condensation device and the software control center. The two parts are electrically connected to realize data transmission and instruction execution, and together constitute an intelligent and automated retrograde condensation control system.

[0137] The software control center boasts powerful data processing and logic control capabilities. It communicates with the retrograde condensation unit in real time via an electrical connection, receiving data from various devices within the unit, including key parameters such as wellhead pressure, preset pressure, wellhead temperature, and produced fluid flow rate. Based on this data, the software control center precisely controls the retrograde condensation unit using pre-set logic control procedures.

[0138] In actual application, the software control center calculates appropriate control instructions based on the real-time status of the produced fluid and the preset control objectives, and transmits these instructions to the reverse condensation device via an electrical connection. Upon receiving the instructions, the reverse condensation device immediately executes the corresponding action, such as adjusting the preset pressure value of the pressure control device or activating the heating device for heating. The software control center also adjusts and optimizes parameters based on actual needs to adapt reverse condensation control to different wellheads and fluid properties.

[0139] Example 6

[0140] The reverse condensation method of the present invention is applied to the aforementioned reverse condensation device and comprises at least the following steps:

[0141] Filling the control component of the pressure control device in the reverse condensation device with pressure fluid and maintaining the pressure at a preset pressure value;

[0142] The control component closes the fluid channel of the pressure control device when the wellhead pressure value of the produced fluid reaching the wellhead is not greater than the preset pressure value, so as to block the outflow of the produced fluid and form a pressure build-up in the well, thereby preventing the pressure in the well from being reduced to the point where condensation occurs.

[0143] Specifically, the reverse condensation method relies on the reverse condensation device to achieve effective control of the produced fluid. First, the control component of the pressure control device in the reverse condensation device should be filled with pressure fluid. The pressure fluid can be injected through a special ring pressure control component, and ensure that its pressure is maintained at a preset pressure value. When the produced fluid flows out from the wellhead, the accurate data of the wellhead pressure can be obtained in real time through the pressure detector in the reverse condensation device. When it is detected that the wellhead pressure value is not greater than the preset pressure value, the closing mechanism of the control component is activated. At this time, the control component is rapidly inflated under the action of the pressure fluid injected by the ring pressure control component, and the fluid channel of the pressure control device is tightly closed. In this way, the outflow of the produced fluid can be quickly and effectively blocked, so that a pressure-holding state is formed in the well, so as to avoid the occurrence of condensation caused by too low pressure in the well.

[0144] In one example, the preset pressure value is not less than a critical wellhead pressure value corresponding to when condensation of the bottom hole gas phase is about to occur.

[0145] Specifically, in the practical application of the retrograde condensation method, setting a preset pressure value is crucial. The critical wellhead pressure is the wellhead pressure at which condensation of the bottomhole gas phase begins. When the wellhead pressure falls below this critical value, the gas components in the bottomhole gas phase gradually precipitate due to the reduced pressure, forming condensate.

[0146] Therefore, when setting the preset pressure value, it must be ensured to be no 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 based on the actual wellhead conditions and the properties of the produced fluid, through a combination of theoretical calculations and experimental verification. At the same time, wellhead pressure will also vary during the different stages of oil and gas well production. The preset pressure value must be adjusted promptly based on these changes in wellhead pressure to ensure that, under a reasonable production system, the occurrence of condensation contamination can be prevented and controlled with the help of anti-condensation devices, thereby ensuring the production capacity and recovery rate of the oil and gas reservoir.

[0147] In one example, the reverse condensation method further includes the steps of: detecting the wellhead temperature value of the produced fluid when it reaches the wellhead by a temperature detector, and when the wellhead temperature value is lower than the lowest temperature at which wax is easily formed, turning on the heating device to heat the produced fluid.

[0148] Specifically, in the implementation of 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. Because the temperature is too low, it can cause wax deposition, which can seriously affect the fluid's fluidity and even cause pipe and equipment blockage. Therefore, it is necessary to use a temperature detector to monitor the wellhead temperature of the produced fluid in real time when it reaches the wellhead, and cooperate with heating equipment to prevent and remove wax.

[0149] When the temperature detector detects that the wellhead temperature is lower than the lowest temperature prone to wax formation, the heating equipment is immediately started to heat the produced fluid. The power and heating time of the heating equipment can be adjusted through the control component to ensure that the temperature of the produced fluid can be stably maintained above the lowest temperature prone to wax formation, thereby achieving the purpose of preventing and removing wax.

[0150] Furthermore, the minimum temperature at which the produced fluid is prone to wax formation is set to 60-65°C.

[0151] Furthermore, when the wax deposition in the produced fluid is serious, chemical agents can be added to the heating equipment through the filling switch to remove the paraffin in the produced fluid, and further prevent wax deposition, thereby achieving the purpose of wax removal and wax prevention.

[0152] Specifically, the chemical agent may include organic solvents such as mixed benzene, light oil, alcohol ether, etc.

[0153] By implementing this step, wax deposition caused by low temperature can be effectively prevented, and the fluidity and stability of the produced fluid can be maintained, which can also reduce pipeline blockage and maintenance costs caused by wax deposition.

[0154] In order to better understand the reverse condensation method of the present invention, Figure 1The specific implementation steps of the reverse condensation operation are further explained.

[0155] The specific implementation steps of the reverse condensation operation of the present invention may include:

[0156] (1) The bottom hole fluid flows through the tubing in the wellbore to the surface wellhead to form produced fluid, which then enters the reverse condensation device through the inlet valve;

[0157] (2) The produced fluid enters the heating equipment through the inlet insulating short section. The temperature detector and pressure detector can detect the temperature and pressure of the produced 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 produced fluid is too low (generally lower than the lowest temperature T at which the fluid is prone to waxing, which is generally set at 60-65°C), the control component adjusts the switch to heat the electric heating network inside the heating device, thereby increasing the temperature of the produced fluid and achieving the purpose of preventing and removing wax. When the temperature of the produced fluid reaches T, the adjustment switch automatically cuts off the power and stops heating.

[0159] (4) The produced fluid enters the pressure control device through the outlet insulating short section. The ring pressure control component on the pressure control device controls the pressure of the ring pressure rubber ring to maintain it at a preset pressure value P1. The setting of P1 should be no less than (greater than or equal to) the wellhead pressure value corresponding to the time when the bottom hole gas phase is about to condense, that is, P1 should be greater than or equal to the lowest pressure value of the reverse condensation wellhead;

[0160] (5) If the pressure of the ring pressure rubber ring is lower than P1, the ring pressure control unit will automatically inject pressure fluid into the ring pressure rubber ring to keep the pressure of the ring pressure rubber ring always stable at the P1 level;

[0161] (6) The annular pressure control component also receives the wellhead pressure value P2 of the produced fluid transmitted by the pressure detector. The annular pressure control component can appropriately adjust the height of P1 according to the size 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 rubber ring expands and fills the fluid channel of the pressure control device, and the produced fluid temporarily stops passing through, causing the well to begin to hold pressure, thereby controlling the bottom hole pressure and achieving the purpose of reverse condensation;

[0162] (7) When P2 is not greater than P1, the well begins to hold pressure and control the bottom hole fluid to 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 device through the adjustment switch to start heating to prevent the produced fluid from waxing and clogging the device. It also plays a role in 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 reverse condensation device is seriously waxed, or if it is necessary to add chemical agents to control / prevent waxing of the produced fluid, the chemical agents can be added to the produced fluid in the heating device 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 boosting equipment through the one-way short joint until it flows out of the outlet valve and the outflow device. The one-way short joint is mainly used to prevent the fluid from flowing back. The auxiliary boosting equipment is mainly used 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] The present invention uses a condensate oil and gas reservoir fluid in the Sichuan Basin as the injection fluid and applies it to a retrograde condensation device for experimentation.

[0167] The injection fluid is injected from the inlet of the reverse condensation device, and the injection fluid is set to four different temperatures and pressures, corresponding to four different wellhead pressure values ​​and wellhead temperature values ​​of the produced fluid:

[0168] ①Injection fluid pressure>P1, injection fluid temperature>T;

[0169] ②Injection fluid pressure>P1, injection fluid temperature<T;

[0170] ③Injection fluid pressure < P1, injection fluid temperature > T;

[0171] ④Injection fluid pressure < P1, injection fluid temperature < T.

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

[0173] The experimental results show that:

[0174] Solution ①: The heating device of the reverse condensation unit did not start heating, and the pressure control device did not close the fluid channel. That is, the injected fluid was not heated and passed through the unit smoothly.

[0175] Solution ②: The heating device of the reverse condensation unit is started, and the pressure control device does not block the fluid channel. That is, the injected fluid is heated and passes through the unit smoothly. When the injected fluid temperature reaches T, the heating device stops heating.

[0176] Solution ③: The heating device of the reverse condensation device is not started to heat, and the pressure control device closes the fluid channel. That is, the injected fluid is not heated and the device is closed to form a pressure-blocking state. When the pressure of the injected fluid reaches P1, the fluid channel of the pressure control device is opened and the fluid passes through the device smoothly.

[0177] Solution ④: The heating device of the reverse condensation unit starts heating, and the pressure control device closes the fluid channel. That is, the injected fluid is heated and the device is closed to form a pressure buildup. When the injected fluid pressure reaches P1 and the temperature reaches T, the fluid channel of the pressure control device opens, allowing the fluid to pass smoothly through the device, and the heating device stops heating. See Table 1 for details.

[0178] Table 1 Experimental scheme setting conditions and effect comparison table

[0179]

[0180] The above experiments show that the reverse 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 reverse condensation device can temporarily suspend the flow of the produced fluid through the ring pressure device, causing the well to begin to build up pressure, thereby controlling the bottomhole pressure and achieving the purpose of reverse condensation. When the produced fluid temperature is low, the reverse condensation device can heat the produced fluid through the heating device to increase the temperature of the produced fluid, thereby preventing and removing paraffin.

[0181] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A reverse condensation device, characterized in that: The reverse condensation device is arranged at the wellhead and connected to the tubing string in the wellbore, and includes a pressure control device with a fluid channel, the fluid channel is used for the produced fluid in the tubing string to flow outward, and the fluid channel is provided with a control component fixed to the inner wall of the channel, the control component is filled with pressure 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 value of the produced fluid is not greater than the preset pressure value, so as to form a pressure hold in the well and prevent the pressure in the well from being reduced to the point where condensation occurs.

2. The reverse condensation device according to claim 1, characterized in that The control component is a ring-pressed rubber ring, the outer ring of which is fixedly laid on the inner wall of the fluid channel. The ring body of the ring-pressed rubber ring is filled with the pressure fluid, and the ring-pressed rubber ring can expand its inner ring toward the center under the pressure of the pressure fluid to close the fluid channel.

3. The reverse condensation device according to claim 2, characterized in that: The annular pressure rubber ring is connected to an annular pressure control component, which is used to inject the pressure fluid into the annular pressure rubber ring and can maintain the pressure of the pressure fluid in the annular pressure rubber ring at the preset pressure value.

4. The reverse condensation device according to claim 3, characterized in that: The inlet end of the pressure control device is provided with a pressure detector for detecting the wellhead pressure of the produced fluid. The pressure detector is electrically connected to the ring pressure control component, and the ring pressure control component can adjust the size of the preset pressure value according to the wellhead pressure value detected by the pressure detector.

5. The reverse condensation device according to claim 1, characterized in that: The reverse condensation device further 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.

6. The reverse condensation device according to claim 5, characterized in that: The heating device is provided with a control component and a temperature detector. The temperature detector is electrically connected to the control component. The control component can control the heating device to heat the produced fluid according to the temperature information detected by the temperature detector.

7. A reverse condensation method, characterized in that: The method is applied to the reverse condensation device according to any one of claims 1 to 6, comprising at least the following steps: Filling a control component of a pressure control device in the reverse condensation device with pressure fluid and maintaining the pressure at a preset pressure value; The control component closes the fluid channel of the pressure control device when the wellhead pressure value of the produced fluid reaching the wellhead is not greater than the preset pressure value, so as to block the outflow of the produced fluid and form a pressure buildup in the well, thereby preventing the pressure in the well from being reduced to the point where condensation occurs.

8. The reverse condensation method according to claim 7, characterized in that: The preset pressure value is not less than the critical wellhead pressure corresponding to when the bottom hole gas phase is about to condense.

9. The reverse condensation method according to claim 8, characterized in that: The reverse condensation method further comprises the steps of: The wellhead temperature value of the produced fluid when it reaches the wellhead is detected by a temperature detector. When the wellhead temperature value is lower than the lowest temperature at which wax is easily formed, the heating device is turned on to heat the produced fluid.

10. A reverse condensation system, characterized in that: The reverse condensation system comprises the reverse condensation device according to any one of claims 1 to 6 and a software control center, wherein the software control center is electrically connected to the reverse condensation device and can control the reverse condensation device to operate according to a preset logic control program.

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