CN116498235A - Underground circulating device with fixed water injection pipe column backwashing function and backwashing method - Google Patents

Abstract

The invention belongs to the technical field of oil recovery, gas recovery and water injection in oil and gas fields, and discloses a downhole circulation device and a backwashing method with a backwashing function of a fixed water injection string. Clean water enters the well flushing channel in the eccentric working barrel from the annular space, and passes through the hanger from the inside of the sealing module to form a well flushing channel; the hydraulic control fluid enters the hydraulic control piston cavity from the hydraulic control pipeline, and the hydraulic control piston overcomes the pressure of the spring to Moving down, the eccentric backwash channel is opened. The opening pressure of the hydraulic control piston provided by the present invention is not changed by the change of the water injection pressure, and it is always opened and closed under the design pressure, and there is no additional requirement on the pressure of the production well. The eccentric working barrel provided by the present invention ensures the internal diameter of the pipe string, so that it can meet the requirements of the normal water injection pipe string segmented and delaminated, as well as the strength requirements of the pipe string. The design of the eccentric backwashing channel greatly increases the displacement of the well washing, improves the cleaning ability and entrainment ability, and reduces the requirements for ground facilities.

Description

Downhole circulation device and backwashing method with fixed water injection string backwashing function

technical field

The invention belongs to the technical field of oil recovery, gas recovery and water injection in oil and gas fields, and in particular relates to a downhole circulation device and a backwashing method with a backwashing function of a fixed water injection string.

Background technique

At present, the fixed sand control water injection strings used in various oilfields have the problem of difficult backwashing or inability to wash the well. During the water injection process, as the injection time continues to increase, impurities in the water gradually block the channel, resulting in difficulty in water injection or even shutdown of the pump. If cleaning is to be carried out, all or part of the pipe string in the well needs to be pulled out, large-scale equipment and several days are needed, and the cost ranges from hundreds of thousands to millions.

Through the above analysis, the existing problems and defects of the prior art are: the existing fixed water injection string does not have the function of backwashing, so that the fixed water injection string blocks the channel during cleaning, affecting the next production. Moreover, the cleaning of the existing fixed water injection string is time-consuming and laborious, which makes the cleaning cost high.

Contents of the invention

In order to overcome the problems existing in the related technologies, the disclosed embodiments of the present invention provide a downhole circulation device and a backwashing method with a fixed backwashing function of a water injection string.

The technical solution is as follows: the downhole circulating backwashing method with fixed water injection string backwashing function, including:

Clean water enters the well flushing channel in the eccentric working barrel from the annular space, and passes through the hanger from the inside of the sealing module to form a well flushing channel;

The hydraulic control fluid enters the hydraulic control piston cavity from the hydraulic control pipeline, the hydraulic control piston overcomes the pressure of the spring and moves downward, and the eccentric backwash channel is opened.

In one embodiment, before the clean water enters the well flushing channel in the eccentric working barrel from the annular space, the annular space pressure test needs to be carried out. It enters through the air, passes through the annulus of several packers and water distributors, enters the tubing and returns to the ground.

Connect the assembled downhole circulation device with fixed water injection string backwashing function and lower it to the design depth, complete docking with the hanger, adjust the string, sit in the tubing hanger, sit at the wellhead, and seal the hydraulic control line from the wellhead Lead out, connect to the ground control device, and connect to the pressure pump.

In one embodiment, the ground control device is used to control the pressure of the hydraulic control fluid, so that the hydraulic control fluid enters the hydraulic control piston chamber from the hydraulic control pipeline, and the hydraulic control piston moves downward against the pressure of the spring, and the eccentric reaction The washing channel is opened, and the pressure of the liquid control fluid is controlled in real time to collect the downward movement distance of the spring and the opening state of the eccentric backwashing channel, and adjust the pressure of the liquid control fluid according to the opening state of the eccentric backwashing channel, which specifically includes the following steps:

The first step is to obtain the downward movement distance of the spring and the opening state of the eccentric backwash channel during the pressure stabilization period of the hydraulic control fluid. The demand for flow rate control and hydraulic control flow, the open state of the eccentric backwash channel is expressed as the pressure stability of the hydraulic control fluid triggering the frequency increase value l _th of the pressure pump and the dynamic adaptive operating frequency acceleration difference V _th ;

The second step is to detect the adjustment state of the hydraulic control, and exchange information with the neighbors, compare the hydraulic control adjustment amount l with the pressure stability of the hydraulic control fluid to press the pump to increase the frequency l _th , and calculate each and the neighbor according to the variance function of the hydraulic control adjustment The variance V of the hydraulic control adjustment amount in the zone, when a certain l>l _th and V>V _th triggers the pressure adjustment of the hydraulic control fluid;

The third step is to screen the target in the adjacent area, and the adjacent area with the liquid control adjustment amount l≤l _th is used as the target, and the target is prioritized according to the occupancy rate of the target physical resource block;

The fourth step is to select the target in order according to the priority, filter the pressure value switched to the selected target, and perform hydraulic control adjustment and transfer;

The fifth step is to judge the end of the pressure stabilization of the hydraulic control fluid. When the hydraulic control adjustment amount l≤l _th or all targets have been transferred to the hydraulic control adjustment, the pressure stabilization process of the hydraulic control fluid is over, otherwise return to the fourth step , select the next target according to the target priority for hydraulic control adjustment transfer.

In the first step, the dynamic adaptive operating frequency acceleration difference V _th represents the intention of the operating frequency acceleration to stabilize the pressure of the hydraulic control fluid. When the overall hydraulic control adjustment is high, the pressure decreases, and when the overall hydraulic control adjustment is low, the pressure increases. high, the expression is:

V _th =exp(-αE _l )+C

Among them, E _l is the average value of the hydraulic control adjustment value of the current and its adjacent areas, the decay speed of the α control function, and C is a normal constant to prevent V _th from decaying to zero, resulting in the same hydraulic control adjustment in each network, which represents the hydraulic control adjustment. Control the maximum tolerance of unbalanced adjustment, reflecting the opening state of the eccentric backwash channel;

In the second step, detect the hydraulic control adjustment status of itself, and exchange information with the neighbors, and calculate the average value of the spring utility according to the variance function formula of the hydraulic control adjustment; the spring utility function formula is expressed as:

Among them, L _m and L ₀ are the current time delay of the spring and the maximum distance that the spring can receive at present, respectively, R _m and R ₀ are the current speed of the spring and the minimum speed that meets the current requirements of the spring, respectively, u _i is the specific material property The utility function is expressed as follows:

Among them, x and x _{0 are} the state value and spring demand value respectively, _{η o} and σ _o are the pressure parameters and scaling parameter.

Another object of the present invention is to provide a downhole circulation device with fixed water injection string backwash function, which implements the downhole circulation backwash method with fixed water injection string backwash function, and the device includes:

The hydraulic control piston is used for the hydraulic control fluid to enter from the hydraulic control pipeline, and moves downward against the pressure of the spring, and the eccentric backwash channel is opened;

The eccentric working cylinder is used to meet the segmentation and delamination of the normal water injection string and form an eccentric backwash channel;

The eccentric backwash channel is used to use the injected clean water to enter the annular space to form backwash pressure and clean the annular space impurities.

It also includes a pressure difference piston inner cylinder, the upper and lower ends of the pressure difference piston inner cylinder are respectively equipped with a sealing upper joint and a piston outer cylinder, the lower end of the piston outer cylinder is connected with a variable buckle joint through the lower mandrel, and the piston outer cylinder The lower end of the outer side is equipped with a sealing cylinder mandrel;

The outer side of the pressure difference piston inner cylinder is covered with a spring outer cylinder, a spring is installed inside the spring outer cylinder, and a spring pressure cap is installed on the upper end of the spring through a stop pin;

A hydraulic control pipeline is installed on the outer side of the piston outer cylinder through a sealing joint, and the lower end of the hydraulic control pipeline is located inside the mandrel of the sealing cylinder;

Two spring adjusting rings are arranged inside the outer cylinder of the spring, respectively located at the two ends of the spring.

In one embodiment, first sealing rings are respectively installed at the contact positions between the two ends of the spring outer cylinder and the pressure difference piston inner cylinder and the piston outer cylinder;

A second sealing ring, a third sealing ring and a vulcanized anti-off piece are installed at the contact position between the inner cylinder of the differential pressure piston and the outer cylinder of the piston.

In one embodiment, two retaining rings are installed on the outer side of the mandrel of the sealing cylinder, a guide shoe is installed on the outer lower end of the mandrel of the sealing cylinder, and a fourth sealing ring is installed between the mandrel of the sealing cylinder and the guide shoe ;

An NPT plug is installed outside the outer cylinder of the piston.

In one embodiment, a prefabricated hole plug and a reserved hole joint are installed in the middle of the piston outer cylinder;

The retaining ring includes the rigid body of the sealing unit and the sealing rubber arranged at intervals, and the end of the rigid body of the sealing unit forms a positioning short.

Another object of the present invention is to provide an oil recovery and gas recovery water injection equipment in an oil and gas field, the equipment implements the downhole circulation backwashing method with the backwashing function of the fixed water injection string.

Combining all the above-mentioned technical solutions, the advantages and positive effects of the present invention are: the downhole circulation device with fixed water injection string backwashing function provided by the present invention can start the hand pump on the ground, and the fluid can be opened through the hydraulic control pipeline. After the construction is completed, the hand pump at the wellhead is depressurized, and the normal water injection production can be resumed. The construction is simple and reliable, and the cost is low, without any additional equipment.

The opening pressure of the hydraulic control piston provided by the present invention is not changed by the change of the water injection pressure, and it is always opened and closed under the design pressure, and there is no additional requirement on the pressure of the production well. The eccentric working barrel provided by the present invention ensures the internal diameter of the pipe string, so that it can meet the requirements of segmented and delaminated normal water injection pipe strings and the strength requirements of the pipe string. The design of the eccentric backwashing channel greatly increases the displacement of the well washing, improves the cleaning ability and entrainment ability, and reduces the requirements for ground facilities. The device body provided by the present invention has no special hoop thread, so that it has a larger space and is suitable for higher strength and pressure requirements.

The design of the vulcanized sealing part provided by the invention makes it more wear-resistant, impact-resistant and erosion-resistant, and can be used for many times, and the service life, valid period and safety of the tool are guaranteed. The ground control device of the present invention is used to control the pressure of the hydraulic control fluid, so that the hydraulic control fluid enters the hydraulic control piston cavity from the hydraulic control pipeline, the hydraulic control piston moves downward against the pressure of the spring, and the eccentric backwash channel is opened, which can realize intelligent control.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description serve to explain the principles of the disclosure;

Fig. 1 is a schematic diagram of a downhole circulation device with a fixed water injection string backwash function provided by an embodiment of the present invention;

Fig. 2 is an overall structural diagram of a downhole circulation device with a fixed water injection string backwash function provided by an embodiment of the present invention;

Fig. 3 is a partial split view of the sealed upper joint connection provided by the embodiment of the present invention;

Fig. 4 is a partial split view of the connection of the vulcanized anti-dropping parts provided by the embodiment of the present invention;

Fig. 5 is a partial split view of the retaining ring connection provided by the embodiment of the present invention;

Fig. 6 is a schematic diagram of an NPT plug provided by an embodiment of the present invention;

Fig. 7 is a schematic diagram of a reserved hole joint provided by an embodiment of the present invention;

Fig. 8 is a schematic diagram of the hydraulic control piston provided by the embodiment of the present invention;

Fig. 9 is a schematic diagram of the eccentric mandrel provided by the embodiment of the present invention;

In the figure: 1. Seal upper joint; 2. Spring outer cylinder; 3. First sealing ring; 4. Spring cap; 5. Stop pin; 6. Spring adjustment ring; 7. Spring; cylinder; 9, the second seal ring; 10, the third seal ring; 11, vulcanized anti-off parts; 12, piston outer cylinder; 13, seal cylinder mandrel; 14, lower mandrel; 15, retaining ring; Four sealing rings; 17. Guide shoes; 18. Variable buckle joints; 19. NPT plugs; 20. Prefabricated hole plugs; 21. Hydraulic control pipelines; 22. Sealed joints; 23. Reserved hole joints; 24. Seals Unit rigid body; 25, sealing rubber; 26, positioning short circuit.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without departing from the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

Embodiment 1, the embodiment of the present invention provides a downhole circulation device for implementing the backwashing function of a fixed water injection string, including:

The hydraulic control piston is used for the hydraulic control fluid to enter from the hydraulic control pipeline, and moves downward against the pressure of the spring 7, and the eccentric backwash channel is opened;

The eccentric working cylinder is used to meet the segmentation and delamination of the normal water injection string and form an eccentric backwash channel;

The eccentric backwash channel is used to use the injected clean water to enter the annular space to form backwash pressure and clean the annular space impurities.

Specifically, the downhole circulation device with fixed water injection string backwashing function includes:

As shown in Figures 1 to 7, the downhole circulation device with fixed water injection string backwashing function provided by the embodiment of the present invention includes a pressure difference piston inner cylinder 8, and the upper and lower ends of the pressure difference piston inner cylinder 8 are respectively equipped with sealing upper joints 1 And the piston outer cylinder 12, the lower end of the piston outer cylinder 12 is connected with a variable buckle joint 18 through the lower mandrel 14, and the outer lower end of the piston outer cylinder 12 is equipped with a sealing cylinder mandrel 13;

The outer side of the pressure difference piston inner cylinder 8 is covered with a spring outer cylinder 2, and a spring 7 is installed inside the spring outer cylinder 2, and a spring pressure cap 4 is installed on the upper end of the spring 7 through a stop pin 5;

A hydraulic control pipeline 21 is installed on the outside of the piston outer cylinder 12 through a sealing joint 22 , and the lower end of the hydraulic control pipeline 21 is located inside the sealing cylinder mandrel 13 .

In the embodiment of the present invention, two spring adjusting rings 6 are arranged inside the outer cylinder of the spring 7 and are respectively located at two ends of the spring 7 .

In the embodiment of the present invention, first sealing rings 3 are respectively installed at the contact positions between the two ends of the spring outer cylinder 2 and the pressure difference piston inner cylinder 8 and the piston outer cylinder 12 .

In the embodiment of the present invention, a second sealing ring 9 , a third sealing ring 10 and a vulcanized anti-dropping member 11 are installed at the contact position between the inner cylinder 8 of the differential pressure piston and the outer cylinder 12 of the piston.

In the embodiment of the present invention, two retaining rings 15 are installed on the outer side of the mandrel shaft 13 of the sealing cylinder, and guide shoes 17 are installed on the outer lower end of the mandrel shaft 13 of the sealing cylinder. The fourth sealing ring 16.

An NPT plug 19 is installed on the outer side of the piston outer cylinder 12 in the embodiment of the present invention.

A prefabricated hole plug 20 and a reserved hole joint 23 are installed in the middle of the piston outer cylinder 12 in the embodiment of the present invention.

The retaining ring 15 includes a sealing unit rigid body 24 and a sealing rubber 25 arranged at intervals, and a positioning short 26 is formed at the end of the sealing unit rigid body 24 .

In the embodiment of the present invention, the thread of the oil pipe at both ends is corrected according to the standard size, and the oil pipe connected in the middle can use a non-standard direct connection oil pipe thread without a coupling. The overcurrent retaining ring 15 can adopt a metal O-ring to prevent falling. The installation structure is mainly modified. The key is that the elastic force of the spring 7 exceeds the area difference × 10MPa at least.

Embodiment 2, the embodiment of the present invention provides a downhole circulating backwashing method with fixed water injection string backwashing function, including:

Clean water enters the well flushing channel in the eccentric working cylinder (as shown in Figure 9) from the annular space, and passes through the hanger from the inside of the sealing module to form a well flushing channel; the hydraulic control fluid enters the hydraulic control piston cavity from the hydraulic control pipeline, and the hydraulic control piston (as Fig. 8) overcome the pressure of spring 7 and move downwards, and the eccentric backwash channel is opened.

specific,

According to the design, the pre-water injection strings such as packer, sealing cylinder, hanger, water distributor, and sand control screen are lowered. After the packer is set, the water injection string is pulled out and sent in.

According to the structure, length and sealing surface size of the water injection string in the early stage, select the suitable downhole circulation device and short-circuit with various lengths of deployment depth, connect the assembled downhole circulation device and lower it to the design depth, and complete the docking with the hanger , adjust the pipe string, sit in the tubing hanger, sit at the wellhead, lead the hydraulic control pipeline from the wellhead sealing hole, connect it to the ground control device, and connect the pressure pump.

The ground control device is used to control the pressure of the hydraulic control fluid, so that the hydraulic control fluid enters the hydraulic control piston chamber from the hydraulic control pipeline, the hydraulic control piston overcomes the pressure of the spring 7 and moves downward, and the eccentric backwash channel is opened, so that The control of the pressure of the hydraulic control fluid includes:

Real-time acquisition of the downward movement distance of the spring 7 and the opening state of the eccentric backwashing channel, according to the opening state of the eccentric backwashing channel, the pressure of the hydraulic control fluid is regulated, specifically including the following steps:

The first step is to obtain the downward movement distance of the spring 7 and the opening state of the eccentric backwash channel during the pressure stabilization period of the hydraulic control fluid. The downward movement distance of the spring 7 is expressed as the demand of the spring 7 for the downward movement pressure, specifically The demand of the spring 7 on the hydraulic control flow rate and liquid control flow, and the open state of the eccentric backwash channel are expressed as the pressure stability of the hydraulic control fluid triggering the frequency increase value l _th of the pressure pump and the dynamic adaptive operating frequency acceleration difference V _th ;

The second step is to detect the adjustment state of the hydraulic control, and exchange information with the neighbors, compare the hydraulic control adjustment amount l with the pressure stability of the hydraulic control fluid to press the pump to increase the frequency l _th , and calculate each and the neighbor according to the variance function of the hydraulic control adjustment The variance V of the hydraulic control adjustment amount in the zone, when a certain l>l _th and V>V _th triggers the pressure adjustment of the hydraulic control fluid;

The third step is to screen the target in the adjacent area, and the adjacent area with the liquid control adjustment amount l≤l _th is used as the target, and the target is prioritized according to the occupancy rate of the target physical resource block;

The fourth step is to select the target in order according to the priority, filter the pressure value switched to the selected target, and perform hydraulic control adjustment and transfer;

The fifth step is to judge the end of the pressure stabilization of the hydraulic control fluid. When the hydraulic control adjustment amount l≤l _th or all targets have been transferred to the hydraulic control adjustment, the pressure stabilization process of the hydraulic control fluid is over, otherwise return to the fourth step , select the next target according to the target priority for hydraulic control adjustment transfer;

The dynamic adaptive operating frequency acceleration difference V _th in the first step represents the intention of the operating frequency acceleration to stabilize the pressure of the hydraulic control fluid. When the overall hydraulic control adjustment is high, the pressure decreases, and when the overall hydraulic control adjustment is low, the pressure raised, as follows:

V _th =exp(-αE _l )+C

Among them, E _l is the average value of the hydraulic control adjustment value of the current and its adjacent areas, the decay speed of the α control function, and C is a normal constant to prevent V _th from decaying to zero, resulting in the same hydraulic control adjustment in each network, which represents the hydraulic control adjustment. Control the maximum tolerance of unbalanced adjustment, reflecting the opening state of the eccentric backwash channel;

In the second step, detect the hydraulic control adjustment state of itself, and exchange information with the neighbors, and calculate the spring 7 utility mean value according to the hydraulic control adjustment variance function formula; the spring 7 utility function formula is expressed as:

Among them, L _m and L ₀ are the current time delay of the spring (7) and the maximum distance that the spring (7) can receive at present, R _m and R ₀ are the current speed of the spring (7) and the current required distance of the spring (7). Running the minimum speed, u _i is the utility function for a specific material property, expressed as follows:

Among them, x and x ₀ are the state value and the demand value of the spring (7) respectively, η _o and σ _i are set in order to make the function range in [0,1] and satisfy u _i =0.5 when x=x ₀ Pressure parameter and scaling parameter.

After the annular space pressure test, start the pump to the design pressure and keep the pressure constant. At this time, the backwash channel is opened, and the well flushing fluid enters from the environmental control, passes through the annulus of several packers and water distributors, enters the tubing and returns out to the ground. Display, the annular flow channel is open. After the well flushing is completed, the pressure of the hand pump is released, the channel is closed, and water is injected normally.

In the embodiment of the present invention, the working principle of the downhole circulation device with fixed water injection string backwashing function includes:

The opening pressure of the hydraulic control piston provided by the present invention is not changed by the change of the water injection pressure, and it is always opened and closed under the design pressure, and there is no additional requirement on the pressure of the production well.

The eccentric working barrel provided by the present invention ensures the internal diameter of the pipe string, so that it can meet the requirements of segmented and delaminated normal water injection pipe strings and the strength requirements of the pipe string.

The design of the eccentric backwashing channel greatly increases the displacement of the well washing, improves the cleaning ability and entrainment ability, and reduces the requirements for ground facilities.

The device body provided by the present invention has no special hoop thread, so that it has a larger space and is suitable for higher strength and pressure requirements.

The design of the vulcanized anti-off piece provided by the invention makes it more wear-resistant, impact-resistant and erosion-resistant, and can be used for many times. The service life, valid period and safety of the tool are guaranteed.

In the above-mentioned embodiments, the descriptions of each embodiment have their own emphases, and for parts that are not detailed or recorded in a certain embodiment, refer to the relevant descriptions of other embodiments.

The above is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field is within the technical scope disclosed in the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles shall fall within the protection scope of the present invention.

Claims (10)

1. A downhole circulation backwashing method with a fixed water injection string backwashing function, characterized in that the method comprises: Clean water enters the well flushing channel in the eccentric working barrel from the annular space, and passes through the hanger from the inside of the sealing module to form a well flushing channel; The hydraulic control fluid enters the hydraulic control piston cavity from the hydraulic control pipeline, the hydraulic control piston overcomes the pressure of the spring (7) and moves downward, and the eccentric backwash channel is opened. 2. The downhole circulating backwashing method with fixed water injection string backwashing function according to claim 1, characterized in that, before the clean water enters the well-flushing channel in the eccentric working cylinder from the annular space, the pressure test of the annular space is required to start After the pump reaches the design pressure, keep the pressure constant, the eccentric backwash channel is opened, and the well flushing fluid enters from the annulus, passes through the annulus of several packers and water distributors, enters the tubing and returns to the surface. 3. The downhole circulating backwashing method of the fixed water injection string backwashing function according to claim 2, is characterized in that, also comprises: Connect the assembled downhole circulation device with fixed water injection string backwashing function and lower it to the design depth, complete docking with the hanger, adjust the string, sit in the tubing hanger, sit at the wellhead, and seal the hydraulic control line from the wellhead Lead out, connect to the ground control device, and connect to the pressure pump. 4. The downhole circulating backwashing method with fixed water injection string backwashing function according to claim 3, characterized in that, the ground control device is used to control the pressure of the hydraulic control fluid, so that the hydraulic control fluid is controlled from the liquid control The pipeline enters the hydraulic control piston cavity, the hydraulic control piston overcomes the pressure of the spring (7) and moves downward, the eccentric backwash channel opens, and the pressure of the hydraulic control fluid is controlled to collect the downward movement distance and eccentricity of the spring (7) in real time. According to the open state of the backwash channel, the pressure of the hydraulic control fluid is adjusted according to the open state of the eccentric backwash channel, which specifically includes the following steps: The first step is to obtain the downward movement distance of the spring (7) and the opening state of the eccentric backwash channel during the pressure stabilization period of the hydraulic control fluid. The downward movement distance of the spring (7) is expressed as the downward movement of the spring (7) The demand for pressure is specifically the demand of the spring (7) for the hydraulically controlled flow rate and hydraulically controlled flow rate. The open state of the eccentric backwash channel is expressed as the pressure stability of the hydraulically controlled fluid triggering the frequency increase value l _th of the pressure pump and the dynamic adaptive operating frequency acceleration difference V _th ; The second step is to detect the adjustment state of the hydraulic control, and exchange information with the neighbors, compare the hydraulic control adjustment amount l with the pressure stability of the hydraulic control fluid to press the pump to increase the frequency l _th , and calculate each and the neighbor according to the variance function of the hydraulic control adjustment The variance V of the hydraulic control adjustment amount in the zone, when a certain l>l _th and V>V _th triggers the pressure adjustment of the hydraulic control fluid; The third step is to screen the target in the adjacent area, and the adjacent area with the liquid control adjustment amount l≤l _th is used as the target, and the target is prioritized according to the occupancy rate of the target physical resource block; The fourth step is to select the target in order according to the priority, filter the pressure value switched to the selected target, and perform hydraulic control adjustment and transfer; The fifth step is to judge the end of the pressure stabilization of the hydraulic control fluid. When the hydraulic control adjustment amount l≤l _th or all targets have been transferred to the hydraulic control adjustment, the pressure stabilization process of the hydraulic control fluid is over, otherwise return to the fourth step , select the next target according to the target priority for hydraulic control adjustment transfer. 5. The downhole circulating backwashing method with fixed water injection string backwashing function according to claim 4, characterized in that, in the first step, the dynamic adaptive operating frequency acceleration difference V _th represents the impact of the operating frequency acceleration on the liquid The intention of controlling the pressure of the fluid is stable, the pressure decreases when the overall hydraulic control adjustment is high, and the pressure increases when the overall hydraulic control adjustment is low, the expression is: V _th =exp(-αE _l )+C Among them, El is the average value of the hydraulic control adjustment value of the current and its adjacent areas, the decay speed of the α control function, and C is a normal number to prevent V _th from decaying to zero, resulting in the same hydraulic control adjustments in each network, which represents the hydraulic control adjustment. Adjust the maximum tolerance of imbalance to reflect the open state of the eccentric backwash channel; In the second step, detect the hydraulic control adjustment state of itself, and exchange information with the neighbors, and calculate the utility mean value of the spring (7) according to the hydraulic control adjustment variance function formula; the spring (7) utility function formula is expressed as: Among them, L _m and L ₀ are the current time delay of the spring (7) and the maximum distance that the spring (7) can receive at present, R _m and R ₀ are the current speed of the spring (7) and the current required distance of the spring (7). Running the minimum speed, u _i is the utility function for a specific material property, expressed as follows: Among them, x and x ₀ are the state value and the demand value of the spring (7) respectively, η _i and σ _i are set in order to make the function range in [0,1] and satisfy u _i =0.5 when x=x ₀ Pressure parameter and scaling parameter. 6. A downhole circulation device with fixed water injection string backwash function, characterized in that the device implements the downhole circulation backwash method with fixed water injection string backwash function described in any one of claims 1-5, the device include: The hydraulic control piston is used for the hydraulic control fluid to enter from the hydraulic control pipeline, and overcomes the pressure of the spring (7) to move downward, and the eccentric backwash channel is opened; The eccentric working cylinder is used to meet the segmentation and delamination of the normal water injection string and form an eccentric backwash channel; The eccentric backwash channel is used to use the injected clean water to enter the annular space to form backwash pressure and clean the annular space impurities. 7. The downhole circulation device with fixed water injection string backwashing function according to claim 6, characterized in that it also includes a pressure difference piston inner cylinder (8), and the upper and lower ends of the pressure difference piston inner cylinder (8) are respectively A sealed upper joint (1) and a piston outer cylinder (12) are installed, and the lower end of the piston outer cylinder (12) is connected with a variable buckle joint (18) through a lower mandrel (14), and the outer side of the piston outer cylinder (12) The lower end is equipped with a sealing cylinder mandrel (13); The outer side of the pressure difference piston inner cylinder (8) is provided with a spring outer cylinder (2), and a spring (7) is installed inside the spring outer cylinder (2), and the upper end of the spring (7) passes through the stop pin (5). ) is equipped with a spring pressure cap (4); A hydraulic control pipeline (21) is installed on the outer side of the piston outer cylinder (12) through a sealing joint (22), and the lower end of the hydraulic control pipeline (21) is located inside the sealing cylinder mandrel (13); The outer cylinder of the spring (7) is provided with two spring adjusting rings (6) respectively located at two ends of the spring (7). 8. The downhole circulation device with fixed water injection string backwashing function according to claim 7, characterized in that, the two ends of the spring outer cylinder (2) are connected to the differential pressure piston inner cylinder (8) and the piston outer cylinder ( 12) The first sealing ring (3) is respectively installed at the contact position; A second seal ring (9), a third seal ring (10) and a vulcanization anti-off piece (11) are installed at the contact position between the pressure difference piston inner cylinder (8) and the piston outer cylinder (12). 9. The downhole circulation device with fixed water injection string backwashing function according to claim 7, characterized in that two retaining rings (15) are installed on the outer side of the mandrel shaft (13) of the sealing cylinder, and the sealing cylinder A guide shoe (17) is installed at the outer lower end of the mandrel (13), and a fourth sealing ring (16) is installed between the sealing cylinder mandrel (13) and the guide shoe (17); An NPT plug (19) is installed on the outer side of the piston outer cylinder (12). 10. The downhole circulation device with fixed water injection string backwashing function according to claim 7, characterized in that a prefabricated hole plug (20) and a reserved hole joint ( twenty three); The retaining ring (15) includes a sealing unit rigid body (24) and a sealing rubber (25) arranged at intervals, and the end of the sealing unit rigid body (24) forms a positioning short (26).