A negative pressure plugging and stratum extrusion filling sand prevention integrated pipe column and process

Abstract

The present application relates to the oil field drilling technology field, specifically relates to a kind of negative pressure plugging and formation extrusion filling sand prevention integrated pipe column and process, the pipe column from bottom to top includes tail pipe, packer and negative pressure plugging device, and is connected to wellhead by tubing, the negative pressure plugging device includes negative pressure plugging work cylinder and the negative pressure plugging work core that can be put into, can be backwashing.The present application is integrated by being thrown in the negative pressure plugging work core and fixed negative pressure plugging work cylinder in a pipe column, and high-efficiency plugging is realized using Venturi jet principle, after plugging is completed, negative pressure plugging work core can be backwashed and recovered, then by being thrown in closed sliding sleeve and steel ball and pumping and setting, the plugging passage on negative pressure plugging work cylinder is closed, pipe column flow passage is switched to straight-through mode, to create conditions for subsequent sand washing and extrusion filling sand prevention operation, to realize the continuous construction of three processes of plugging, sand washing and sand prevention with one operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oilfield drilling technology, and particularly relates to a negative pressure plugging and stratum extrusion and filling sand prevention integrated pipe column and process. BACKGROUND

[0002] In the field of oilfield exploitation, for the cementation loose sand production oil and water well, before the stratum extrusion and filling sand prevention construction, the near wellbore zone is subjected to plugging, which is a crucial pretreatment process. This is because the near wellbore stratum pollution caused by drilling, operation or production process will seriously restrict the oil and gas flow channel, and affect the final sand prevention effect and wellbore productivity. Therefore, the standard operation process usually includes the following steps in turn: firstly, the near wellbore stratum is subjected to plugging to restore the stratum permeability, then sand washing operation is performed to remove the accumulated sand in the wellbore and the plugging backflow, and finally the stratum extrusion and filling sand prevention is implemented, so as to construct a near wellbore environment which can effectively prevent sand and has high flow conductivity.

[0003] However, the existing conventional technology regards the above plugging, sand washing and sand prevention processes as independent construction links, and the process flow has inherent defects. Specifically, after the stratum plugging is completed, the plugging pipe column must be completely pulled out of the wellbore, and then a special sand washing pipe column is lowered to perform sand washing operation; after the sand washing is completed, the sand washing pipe column is pulled out again, and finally the sand prevention pipe column is lowered to perform extrusion and filling operation. For some complex well conditions, even multiple pipe columns need to be replaced. This operation mode of "completing one process and pulling out one pipe column" leads to frequent pulling and lowering of the pipe column during the construction period, which has become the main bottleneck restricting the improvement of operation efficiency.

[0004] Therefore, the multiple pulling and lowering of the pipe column not only significantly increases the construction time and labor intensity, but also directly increases the operation cost, and magnifies the well control risk and tool failure probability caused by frequent operation. Therefore, the technical field urgently needs a technical solution which can effectively integrate key processes, so as to sequentially complete the plugging, sand washing and sand prevention construction by one pipe column through the innovation of process and tool, so as to fundamentally solve the timeliness problem under the existing technical mode, and meet the urgent needs of oilfield cost reduction and efficiency improvement. SUMMARY

[0005] Therefore, the technical field urgently needs a technical solution which can effectively integrate key processes, so as to sequentially complete the plugging, sand washing and sand prevention construction by one pipe column through the innovation of process and tool, so as to fundamentally solve the timeliness problem under the existing technical mode, and meet the urgent needs of oilfield cost reduction and efficiency improvement.

[0006] Based on the above purpose, the application provides a negative pressure plug-removing and stratum extrusion and filling sand prevention integrated pipe column, which comprises a tail pipe, a packer and a negative pressure plug-removing device from bottom to top, and is connected to a well head through a tubing.

[0007] As a preferred technical scheme of the application, the jet pump structure comprises sequentially connected liquid inlet pipe, nozzle, throat pipe and diffusion pipe, and the negative pressure zone is formed in the negative pressure pipe communicated with the throat pipe.

[0008] As a preferred technical scheme of the application, the negative pressure plug-removing working barrel is internally provided with a bridge, the bridge is provided with a side hole and a bypass hole, the side hole constitutes a part of the plug-removing outlet passage, and the bypass hole is used for guiding the stratum fluid from the tail pipe into the negative pressure pipe.

[0009] As a preferred technical scheme of the application, the channel switching mechanism is a seat sealing structure arranged in the bridge, which is used for cooperating with the drop-in closing part and sealing the side hole of the bridge through the drop-in closing part.

[0010] As a preferred technical scheme of the application, the drop-in closing part comprises a closing sliding sleeve and a steel ball matched with the closing sliding sleeve, the lower end of the closing sliding sleeve is provided with a locking structure matched with the locking ring in the inside of the negative pressure plug-removing working barrel to realize one-time locking, and the steel ball is used for cooperating with the closing sliding sleeve to jointly complete setting to seal the side hole under hydraulic drive, and remains in an irreversible sealing state in the process of the operation.

[0011] As a preferred technical scheme of the present application, the negative pressure plugging working core is coaxially provided with a catching head, a liquid inlet pipe, a sealing head, a nozzle seat and a nozzle, a throat seat, a diffusion pipe and a liquid outlet pipe along the axial direction in sequence; the liquid inlet pipe constitutes a liquid inlet channel of the Venturi jet assembly, the left end of which is sleeved with the catching head, and the right end of which extends to the inside of the sealing head and is provided with a nozzle seat, and the nozzle seat is connected with a nozzle; the throat seat is sleeved in the right end of the inside of the sealing head, and a throat pipe located downstream of the nozzle is installed in the throat seat, and the right end of the throat pipe is connected with a throat pipe extension pipe; the diffusion pipe is sleeved outside the throat seat, and the right end of the diffusion pipe is connected with the liquid outlet pipe, and a first through hole is formed in the pipe wall of the liquid outlet pipe; the nozzle is used for accelerating the power liquid to form a negative pressure in the throat pipe area; a liquid suction hole is formed in the sealing head, and is used for guiding the formation fluid into the negative pressure area.

[0012] As a preferred technical scheme of the present application, the negative pressure plugging working core is coaxially provided with a catching head, a liquid inlet pipe, a sealing head, a nozzle seat and a nozzle, a throat seat, a diffusion pipe and a liquid outlet pipe along the axial direction in sequence; the liquid inlet pipe constitutes a liquid inlet channel of the Venturi jet assembly, the left end of which is sleeved with the catching head, and the right end of which extends to the inside of the sealing head and is provided with a nozzle seat, and the nozzle seat is connected with a nozzle; the throat seat is sleeved in the right end of the inside of the sealing head, and a throat pipe located downstream of the nozzle is installed in the throat seat, and the right end of the throat pipe is connected with a throat pipe extension pipe; the diffusion pipe is sleeved outside the throat seat, and the right end of the diffusion pipe is connected with the liquid outlet pipe, and a first through hole is formed in the pipe wall of the liquid outlet pipe; the nozzle is used for accelerating the power liquid to form a negative pressure in the throat pipe area; a liquid suction hole is formed in the sealing head, and is used for guiding the formation fluid into the negative pressure area.

[0013] In order to better solve the above technical problems, the present application further provides an integrated process of negative pressure plugging and stratum extrusion filling sand prevention by an integrated pipe column, and the process comprises the following steps:

[0014] S1. pipe column lowering and setting: connecting a pipe column and lowering into a well to a designed depth, setting a packer to seal an oil jacket annulus;

[0015] S2. negative pressure plugging construction: pumping power liquid into a tubing, the power liquid driving a jet pump structure in the negative pressure plugging working core to generate a negative pressure, sucking formation fluid, and after mixing, discharging to an oil jacket annulus and returning to the ground through the plugging outlet channel;

[0016] S3. washing out the negative pressure plugging working core: lifting the pipe column to unseal the packer, and performing reverse circulation well flushing from a casing to wash out the negative pressure plugging working core from a wellbore;

[0017] S4. closing the plugging channel: putting a put-in closing piece into the tubing, and pumping liquid to pressurize, so that the closing piece is set in the negative pressure plugging working cylinder to block the plugging outlet channel;

[0018] S5. Sand washing construction: liquid is pumped from the casing to perform reverse circulation washing, and sand washing is completed;

[0019] S6. Sand control construction: the pipe string is lifted to the sand control design position, and the formation is extruded and filled for sand control construction.

[0020] As a preferred technical solution of the present application, in step S3, a catcher is installed at the wellhead before reverse circulation washing is performed from the casing, for capturing and recovering the negative pressure unblocking work core washed out, and the closing sleeve with a steel ball is put into the closing sleeve in step S4.

[0021] As a preferred technical solution of the present application, in step S4, the pumped liquid is pressurized to a predetermined pressure to make the closing sleeve set and locked.

[0022] The present application has the following beneficial effects: the present application integrates a retrievable negative pressure unblocking work core and a fixed negative pressure unblocking work cylinder in one pipe string, and uses the Venturi jet principle to achieve efficient unblocking, wherein the nozzle-throat structure built in the negative pressure unblocking work core generates strong negative pressure suction of the formation plugging under the driving of the power liquid, and after unblocking is completed, the negative pressure unblocking work core can be washed out and recovered by reverse circulation, and then the closing sleeve and the steel ball are put in and pumped to set, the unblocking channel on the negative pressure unblocking work cylinder is closed, the pipe string flow passage is switched to a straight-through mode, conditions are created for subsequent sand washing and extrusion and filling sand control operations, so that the three processes of unblocking, sand washing and sand control, which are traditionally completed by multiple trips of pipe strings, are realized by one set of pipe string and one trip, and the operation efficiency and economy are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only illustrate the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0024] Figure 1 It is a general pipe string structure diagram of the present application;

[0025] Figure 2 It is a negative pressure unblocking work core structure diagram of the present application;

[0026] Figure 3 It is a negative pressure unblocking work cylinder structure diagram of the present application;

[0027] Figure 4 It is a closing sleeve structure diagram of the present application;

[0028] Figure 5It is the structural schematic view of the negative pressure plug-removing working core and the negative pressure plug-removing working barrel in the plug-removing butt joint state of the application;

[0029] Figure 6 It is the structural schematic view of the closing sliding sleeve and the negative pressure plug-removing working barrel in the sand washing and sand preventing butt joint state of the application;

[0030] Figure 7 It is the negative pressure plug-removing schematic view of the application;

[0031] Figure 8 It is the main view local section structural schematic view of the bridge of the application;

[0032] Figure 9 It is the side section structural schematic view of the bridge of the application.

[0033] In the figure, 100 is the negative pressure plug-removing working barrel; 11 is the upper joint; 12 is the sealing barrel; 13 is the negative pressure pipe; 14 is the bridge seat; 141 is the second through port; 15 is the bridge; 151 is the main body; 152 is the bypass hole; 153 is the side hole; 16 is the lower joint; 17 is the lock ring seat; 18 is the lock ring; 200 is the negative pressure plug-removing working core; 21 is the capturing head; 22 is the liquid inlet pipe; 23 is the sealing head; 231 is the liquid suction hole; 24 is the nozzle seat; 25 is the nozzle; 26 is the throat pipe seat; 27 is the throat pipe; 28 is the throat pipe extension pipe; 29 is the diffusion pipe; 210 is the liquid outlet pipe; 2101 is the first through port; 300 is the oil pipe; 400 is the sleeve pipe; 500 is the packer; 600 is the tail pipe; and 700 is the oil layer. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the application more clear and understandable, the application is further described in detail below in combination with specific embodiments.

[0035] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the application should be the commonly understood meanings by those skilled in the art to which the application belongs. The "first", "second" and similar words used in the application do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, without excluding other elements or objects. "Connection" or "connection" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, which may change accordingly when the absolute position of the described object changes.

[0036] As Figure 1As shown, in the embodiment, a negative pressure plug removal and formation squeeze packing integrated pipe column, the pipe column includes a tail pipe 600, a packer 500 and a negative pressure plug removal device from bottom to top, and is connected to the wellhead through a tubing 300, the negative pressure plug removal device includes a negative pressure plug removal working barrel 100 and a negative pressure plug removal working core 200 which can be put in and washed out; the negative pressure plug removal working core 200 is internally provided with a jet pump structure based on the Venturi principle, for forming a negative pressure zone inside when injecting power fluid; the negative pressure plug removal working barrel 100 is internally provided with a plug removal outlet passage, which is used to guide the mixed fluid to the oil jacket annulus when the negative pressure plug removal working core 200 is docked; the negative pressure plug removal working barrel 100 is also provided with a passage switching mechanism, which is used to receive a put-in type closing piece to permanently block the plug removal outlet passage after the negative pressure plug removal working core 200 is washed out, and convert the internal flow channel of the pipe column into a sand washing and sand prevention mode;

[0037] The above technical scheme can fundamentally solve the efficiency bottleneck problem that the three independent processes of plug removal, sand washing and sand prevention need to be completed by tripping in three times in the conventional process, and the core working principle is to realize "function integration" and "mode switching" through structural innovation. Specifically, the negative pressure plug removal device combines the fixed negative pressure plug removal working barrel 100 with the movable negative pressure plug removal working core 200: during work, the assembled negative pressure plug removal working core 200 is first lowered into the well with the pipe column, and after setting the packer 500, power fluid is pumped through the tubing 300 to drive the Venturi jet mechanism in the negative pressure plug removal working core 200 to generate strong negative pressure, effectively pumping the formation plug, and the mixed liquid is discharged to the oil jacket annulus through the plug removal outlet passage of the negative pressure plug removal working barrel 100 and returned to the ground, completing the plug removal. After the plug removal is completed, the negative pressure plug removal working core 200 is washed out by reverse circulation, and then a closing piece composed of a closing sleeve and a steel ball as recorded in the following text is put in, and pumping makes it set, permanently closing the plug removal passage, thereby converting the internal flow channel of the pipe column into a straight-through structure, preparing for subsequent direct sand washing and squeeze packing sand prevention operations, realizing a major breakthrough of "one trip pipe column" to continuously complete three operations, greatly improving the construction efficiency, significantly reducing the operation cost and reducing the well control risk brought by multiple operations.

[0038] As shown in Figure 1 , Figure 3 and Figure 7 , in the embodiment, the jet pump structure includes a liquid inlet pipe 22, a nozzle 25, a throat pipe 27 and a diffusion pipe 29 connected in sequence, and the negative pressure zone is formed in the negative pressure pipe 13 communicating with the throat pipe 27;

[0039] The technical scheme can solve the technical problem of efficiently generating stable and strong negative pressure in a limited space in a well, and the detailed working principle is as follows: the high-pressure power liquid pumped from the ground flows through the liquid inlet pipe 22 to the nozzle 25, and due to the throttling effect of the nozzle 25, the fluid velocity increases sharply and the pressure decreases, forming a high-speed jet into the inlet of the throat pipe 27. According to the Venturi effect in fluid mechanics, a stable low-pressure area, i.e. a negative pressure area, is formed in the narrow section of the throat pipe 27; the negative pressure area continuously sucks the formation fluid up through the negative pressure pipe 13 connected thereto, and after the two fluids are mixed in the throat pipe 27, they enter the diffusion pipe 29, the flow rate decreases and the pressure recovers, and finally the mixed liquid is discharged, providing a reliable downhole negative pressure generation source, strong suction and stable operation, ensuring the thoroughness of the formation plugging.

[0040] As shown in Figure 7 and Figure 8 In this embodiment, the negative pressure plugging working barrel 100 is internally provided with a bridge 15, the bridge 15 includes a main body 151, the main body 151 is provided with a side hole 153 and a bypass hole 152, the side hole 153 constitutes part of the plugging outlet passage, and the bypass hole 152 is used for guiding the formation fluid from the tail pipe 600 into the negative pressure pipe 13.

[0041] The technical scheme can solve the complex fluid control problem of realizing bidirectional flow of the suction flow channel and the return flow channel in the same compact space without interference, and the working principle is as follows: the bypass hole 152 and the side hole 153 independently machined on the main body 151 of the bridge 15 are precisely utilized to realize the orderly flow of the fluid. In the plugging stage, the formation fluid enters from the tail pipe 600 under the action of negative pressure, flows through the bypass hole 152 of the bridge 15, enters the negative pressure pipe 13, and is finally sucked into the throat pipe 27. At the same time, after the mixed liquid flows out of the negative pressure plugging working core 200, it enters the oil jacket annulus and returns upward through the side hole 153 of the bridge 15, ensuring the clarity and smoothness of the fluid path during the plugging process, avoiding flow mixing and energy loss, and thus improving the efficiency and reliability of the entire plugging system.

[0042] As shown in Figure 7 In this embodiment, the channel switching mechanism is a seat sealing structure arranged in the bridge 15, which is used in cooperation with the drop-in closing piece and seals the side hole 153 of the bridge 15 through the drop-in closing piece.

[0043] The above-mentioned technical solution solves the core technical problem of how to reliably and securely switch between different working modes during a single tubing operation. Specifically, its working principle utilizes a precision-machined sealing structure, such as a step or sealing groove, within the bridge 15 to match a deployed closing element, such as a closing sleeve. When a mode switch is required, the closing element is deployed from the wellhead. Under its own gravity and subsequent hydraulic pressure, it descends to the sealing position within the bridge 15 and tightly seals the side hole 153 of the bridge 15 through a sealing element such as an O-ring. The resulting technical benefits include simple operation, reliable switching, and ensure that during sand flushing and sand control phases, the high-pressure fluid within the tubing does not leak from the unblocking channel but is entirely guided to the formation, guaranteeing the effectiveness and safety of subsequent operations.

[0044] like Figure 7 As shown, in this embodiment, the insertion-type closing component includes a closing sleeve and a matching steel ball. The lower end of the closing sleeve is provided with a locking structure that cooperates with the locking ring 18 inside the negative pressure unblocking working cylinder 100 to achieve one-time locking. The steel ball is used to cooperate with the closing sleeve to jointly complete the setting seal under hydraulic drive to block the side hole 153, and maintains an irreversible blocking state during this construction process.

[0045] The above technical solution solves the problems of final execution and state locking of the mode switching action. Specifically, its working principle is as follows: First, a steel ball of a specific size is inserted into the oil pipe 300. The steel ball falls with the fluid flow and eventually sits on the ball seat inside the closing sleeve, forming an initial seal. Then, pressure is applied from the ground, and the hydraulic pressure acts on the steel ball and the end face of the sleeve it sits on, pushing the entire closing sleeve downward. The lower end of the sleeve is designed with reverse teeth or a similar structure. When it descends to the position of the locking ring 18 inside the negative pressure unblocking working cylinder 100, the two engage mechanically, achieving irreversible permanent locking. At the same time, the seal on the outer wall of the sleeve completely seals the side hole 153 of the bridge 15. Reliable sealing and mechanical locking under high pressure are achieved, ensuring the permanence and robustness of the channel closure, and providing a solid foundation for subsequent high-pressure filling operations.

[0046] like Figure 2As shown, the negative pressure unblocking working core 200 is coaxially provided with the catching head 21, the liquid inlet pipe 22, the sealing head 23, the nozzle seat 24 and the nozzle 25, the throat pipe seat 26, the diffusion pipe 29 and the liquid outlet pipe 210 along its axial direction in sequence; the liquid inlet pipe 22 constitutes a liquid inlet channel of the Venturi jet assembly, the left end of which is sleeved with the catching head 21, and the right end of which extends to the inside of the sealing head 23 and is provided with the nozzle seat 24, and the nozzle seat 24 is connected with the nozzle 25; the throat pipe seat 26 is sleeved in the inside of the right end of the sealing head 23, and the throat pipe 27 downstream of the nozzle 25 is installed in the inside of the throat pipe seat 26, and the right end of the throat pipe 27 is connected with the throat pipe extension pipe 28; the diffusion pipe 29 is sleeved outside the throat pipe seat 26, and the right end of the diffusion pipe 29 is connected with the liquid outlet pipe 210, and the pipe wall of the liquid outlet pipe 210 is provided with the first through hole 2101; the nozzle 25 is used for accelerating the power liquid to form negative pressure in the area of the throat pipe 27; the sealing head 23 is provided with the liquid suction hole 231 for guiding the formation fluid into the negative pressure area;

[0047] The above technical scheme can solve the engineering problem of miniaturization and integration of the Venturi pump and adaptation to the internal space of the oilfield pipe column. Specifically, the working principle is based on the mature Venturi effect, and the high-efficiency energy conversion in the harsh downhole environment is realized through the precise coaxial sleeving combination of the catching head 21, the liquid inlet pipe 22, the sealing head 23, the throat pipe seat 26, the diffusion pipe 29, the liquid outlet pipe 210 and other components. The high-pressure power liquid enters from the liquid inlet pipe 22, is accelerated through the nozzle 25, and forms strong negative pressure in the area of the throat pipe 27. The negative pressure sucks the formation fluid through the liquid suction hole 231 on the sealing head 23. After the two fluids are fully mixed in the throat pipe 27 and the throat pipe extension pipe 28, the power energy is converted into pressure energy in the diffusion pipe 29, and finally the blockage is discharged from the first through hole 2101 in the side wall of the liquid outlet pipe 210, providing a compact structure, high energy conversion efficiency and strong suction capacity of the independent functional module, which is the basis and key to whether the whole integrated technology can successfully realize the negative pressure unblocking function.

[0048] As Figure 3 and Figure 8As shown, the negative pressure plug-removing working barrel 100 is coaxially provided with an upper joint 11, a sealing barrel 12, a negative pressure pipe 13, a bridge seat 14, a lower joint 16 and a lock ring seat 17 along its axial direction in sequence; the sealing barrel 12 is sleeved in the upper joint 11 and is used to form a seal with the sealing head 23 of the negative pressure plug-removing working core 200; the negative pressure pipe 13 is sleeved outside the sealing barrel 12, and its lower end is connected with the bridge 15 in the bridge seat 14, and the bridge 15 is provided with bypass holes 152 and side holes 153 which are isolated from each other; the side wall of the bridge seat 14 is provided with a second through port 141 which is communicated with the side holes 153 of the bridge 15; the lock ring seat 17 is arranged at the right end of the bridge 15, and a lock ring 18 is arranged on the lock ring seat 17; when the negative pressure plug-removing working core 200 is docked in the negative pressure plug-removing working barrel 100, the first through port 2101 on the liquid outlet pipe 210 is aligned and communicated with the side holes 153 and the second through port 141 of the bridge 15, and together forms a plug-removing outlet channel of mixed fluid flowing to the annular space of the oil jacket;

[0049] The above technical scheme can solve the core problem of how the negative pressure plug-removing working core 200 is reliably supported, sealed and accurately communicated with the formation flow channel and the annular space flow channel underground, and the working principle is that a basic platform for accurate positioning, sealing, flow channel guiding and mode switching is provided for the negative pressure plug-removing working core 200. When the negative pressure plug-removing working core 200 is lowered into the negative pressure plug-removing working barrel 100, the sealing head 23 of the negative pressure plug-removing working core 200 forms a seal with the sealing barrel 12 of the negative pressure plug-removing working barrel 100, so that the high-pressure power fluid is prevented from leaking; the lower end of the negative pressure pipe 13 of the negative pressure plug-removing working barrel 100 is communicated with the bypass holes 152 of the bridge 15, and is responsible for guiding the formation fluid to the suction port of the negative pressure plug-removing working core 200; the side holes 153 of the bridge 15 are accurately aligned with the second through port 141 on the bridge seat 14 and the first through port 2101 on the liquid outlet pipe 210 of the negative pressure plug-removing working core 200, and together form a plug-removing mixed liquid discharge channel. The lock ring 18 at the end provides a locking position for the closed sliding sleeve. The negative pressure plug-removing working core 200 can work stably and efficiently, and the structure ensures the smooth switching of the two working modes of "plug removal" and "sand prevention" of the whole system, and is a key fixed component supporting the integrated process.

[0050] The application also provides an integrated process for carrying out negative pressure plugging removal and stratum extrusion and filling sand prevention by an integrated pipe column, which comprises the following steps: S1. pipe column lowering and setting: connecting the pipe column and lowering it into a well to a designed depth, setting a packer 500 to seal the oil jacket annulus; S2. negative pressure plugging removal construction: pumping power fluid into the oil pipe 300, the power fluid driving the jet pump structure in the negative pressure plugging removal working core 200 to generate negative pressure, sucking stratum fluid, and discharging the mixed stratum fluid to the oil jacket annulus and back to the ground through the plugging removal outlet channel; S3. washing out the negative pressure plugging removal working core 200: unsealing the packer 500 by lifting the pipe column, and performing reverse circulation well washing from the casing 400 to wash out the negative pressure plugging removal working core 200 from the wellbore; S4. closing the plugging removal channel: putting a put-in closing piece into the oil pipe 300, and pumping liquid to pressurize and set the closing piece in the negative pressure plugging removal working core 100 to seal the plugging removal outlet channel; S5. sand washing construction: pumping liquid from the casing 400 to perform reverse circulation well washing to complete sand washing; and S6. sand prevention construction: lifting the pipe column to a sand prevention designed position to perform stratum extrusion and filling sand prevention construction.

[0051] The above technical solution can systematically solve the fundamental efficiency bottleneck problem of frequent pipe column lifting and lowering caused by process separation. Specifically, the core working principle is to organically integrate the originally discrete operation steps by using a special tool to form a continuous operation line. When operating, the steps S1 to S6 are strictly executed: pipe column lowering and setting → liquid pumping and negative pressure plugging removal → reverse circulation well washing of the negative pressure plugging removal working core 200 → ball put-in pressure holding and plugging removal channel closing → reverse circulation sand washing → pipe column lifting and stratum extrusion and filling sand prevention. The three or more times of pipe column lifting and lowering operations are compressed into one time, the construction period can be greatly shortened, the equipment occupation time and labor cost are greatly reduced, the safety risks such as blowout are significantly reduced due to the reduction of the number of wellhead opening and closing, and efficient, safe and economic well completion or operation workover is realized.

[0052] Further, in the embodiment, before the reverse circulation well washing from the casing 400 in step S3, a catcher is installed at the wellhead to capture and recover the washed-out negative pressure plugging removal working core 200, and the put-in closing piece in step S4 is a closing sliding sleeve matched with a steel ball.

[0053] The technical scheme can solve the key problem of how to ensure safe recovery of a small tool such as the negative pressure plug removal working core 200 and controllable follow-up injection such as the closing part in a dynamic well washing and injection operation. Specifically, the working principle is to install a catcher at the wellhead to ensure that the negative pressure plug removal working core 200 can be safely and completely recovered in the reverse circulation well washing process. When the negative pressure plug removal working core 200 is washed out in reverse circulation, the catcher is installed above the tubing 300 at the wellhead; when the liquid is pumped from the casing 400 for reverse circulation, the fluid pushes the negative pressure plug removal working core 200 to go up until it is reliably intercepted by the catcher and recovered to the ground. The negative pressure plug removal working core 200 is prevented from hitting the wellhead equipment or falling into the ground flow during the washing process to cause accidents, ensuring the safe performance of subsequent operation steps and realizing the recycling of the core function module. Then, in step S4, after the closing sliding sleeve is injected, a steel ball of a specific size is injected, which is seated on the ball seat of the sliding sleeve and jointly pushes the sliding sleeve to go down to the locking position under the action of hydraulic pressure. The channel switching is realized to ensure that the plug channel can be effectively plugged.

[0054] Further, in the embodiment, in step S4, the liquid is pumped to a predetermined pressure to make the closing sliding sleeve set and lock;

[0055] The technical scheme can solve the problem of how to accurately determine and confirm whether the downhole channel switching action is successfully completed from the ground. Specifically, the working principle is to use the hydraulic system as a power source, gradually increase the tubing 300 pressure to a preset critical value sufficient to overcome the friction of the closing sliding sleeve going down and the engagement resistance of the locking ring 18 through the ground pump truck. When the pressure reaches the predetermined value, it indicates that the closing sliding sleeve has successfully completed the setting and mechanical locking. The design of this pressure indicator makes the key step quantifiable, monitorable and verifiable, realizes the controllability of construction quality, and avoids the construction risk caused by the unclear downhole state.

[0056] Working principle:

[0057] 1. Negative pressure plug removal:

[0058] Firstly, the negative pressure plug removal working core 200 is placed in the negative pressure plug removal working barrel 100, and both are in a plug removal docking state, so that the sealing head 23 and the sealing barrel 12 form a seal through the rubber ring, and the liquid outlet pipe 210 and the bridge 15 form a seal through the rubber ring, and they are lowered into the well in the schematic string structure. Figure 5 The sealing head 23 and the sealing barrel 12 form a seal through the rubber ring, and the liquid outlet pipe 210 and the bridge 15 form a seal through the rubber ring. Figure 1

[0059] Next, the tool is lowered to the designed depth, the packer 500 is set, and the oil-casing annulus is sealed.

[0060] ​Then inject power fluid into the tubing 300, the power fluid well tubing 300 into the sealing cylinder 12, and then through the liquid inlet pipe 22 to the nozzle 25, where the high-speed jet body is injected into the throat pipe 27, while the negative pressure area based on the Venturi principle is formed on the periphery. The negative pressure area in the negative pressure pipe 13 makes the formation fluid enter the lower joint 16 through the tail pipe 600, and then enters the negative pressure pipe 13 through the bypass hole 152 of the bridge 15, and is mixed in the sealing head 23 and enters the throat pipe 27, and then enters the casing 400 through the side hole 153 of the bridge 15 from the liquid outlet pipe 210, and then the casing 400 is pumped to the ground to realize negative pressure unblocking construction.

[0061] 2. Wash negative pressure unblocking working core 200:

[0062] The upper string unblocks the packer 500 to release the casing annulus, open the circulation channel, and install the catcher at the wellhead. The casing 400 is pumped with liquid to perform reverse circulation washing. The reverse circulation here refers to using the original unblocking outlet channel as the inlet channel of high-pressure liquid. Its effect is equivalent to changing the solid arrow (i.e. the arrow representing the mixed liquid flow direction) and the hollow arrow (i.e. the arrow representing the power fluid flow direction) in the original Figure 7 to reverse direction. Under the action of high pressure, the negative pressure unblocking working core 200 will be pushed out of the negative pressure unblocking working cylinder 100 to realize washing out of the wellbore.

[0063] 3. Close the unblocking channel:

[0064] Put the closing sliding sleeve and the matching steel ball into the tubing 300, and pump the liquid in the tubing 300 to 10 MPa to make the closing sliding sleeve and the negative pressure unblocking working cylinder 100 Figure 6 sand washing and sand prevention butt joint state. The closing sliding sleeve and the bridge 15 form a seal through the rubber ring, the side hole 153 of the bridge 15 is closed, and the negative pressure unblocking channel is closed. At the same time, the lower end of the closing sliding sleeve is in the locking state with the locking ring 18 of the negative pressure unblocking working cylinder 100.

[0065] 4. Catch ball and sand washing:

[0066] Install the ball catcher at the wellhead, and pump the liquid in the casing 400 to perform reverse circulation washing and sand washing construction.

[0067] 5. Sand prevention:

[0068] Raise the pipe string to the sand prevention position to perform sand filling and sand prevention construction.

[0069] Those skilled in the art should understand that the above discussion of any embodiment is only intended to be illustrative and is not intended to be in any way limiting to the scope of the present application; under the concept of the present application, the above embodiments or technical features among different embodiments can also be combined, steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for the sake of brevity.

[0070] The present application is intended to cover all such alternatives, modifications, and variations as fall within the scope of the claims. Accordingly, any and all such alternatives, modifications, equivalents, improvements and the like are intended to be encompassed by the present application.

Claims

1. A negative pressure unblocking and stratum extrusion and packing sand prevention integrated pipe column, characterized in that, The pipe column comprises a tail pipe (600), a packer (500) and a negative pressure plug-removing device from bottom to top, and is connected to a wellhead through a tubing (300), the negative pressure plug-removing device comprises a negative pressure plug-removing working barrel (100) and a negative pressure plug-removing working core (200) which can be put in and washed out, the negative pressure plug-removing working core (200) is internally provided with a jet pump structure based on the Venturi principle, for forming a negative pressure zone inside when injecting power fluid, the negative pressure plug-removing working barrel (100) is internally provided with a plug-removing outlet channel, the plug-removing outlet channel is used for guiding mixed fluid to an oil jacket annulus when the negative pressure plug-removing working core (200) is docked, the negative pressure plug-removing working barrel (100) is further provided with a channel switching mechanism, for receiving a put-in type closing part to block the plug-removing outlet channel after the negative pressure plug-removing working core (200) is washed out, converting the internal flow channel of the pipe column into a sand washing and sand preventing mode, the negative pressure plug-removing working barrel (100) is internally provided with a bridge (15), the bridge (15) is provided with a side hole (153) and a bypass hole (152), the side hole (153) constitutes part of the plug-removing outlet channel, the bypass hole (152) is used for guiding formation fluid from the tail pipe (600) into the negative pressure pipe (13) of the jet pump structure, the channel switching mechanism is a seat sealing structure arranged in the bridge (15), used for cooperating with the put-in type closing part, and sealing the side hole (153) of the bridge (15) through the put-in type closing part, the put-in type closing part comprises a closing sliding sleeve and a steel ball matched therewith, the closing sliding sleeve is provided at a lower end with a locking structure matched with a locking ring (18) inside the negative pressure plug-removing working barrel (100), to realize one-time locking, the steel ball is used for cooperating with the closing sliding sleeve to jointly complete setting to block the side hole (153) under hydraulic driving, and to maintain an irreversible blocking state during construction, the negative pressure plug-removing working barrel (100) is coaxially provided with an upper joint (11), a sealing barrel (12), a negative pressure pipe (13), a bridge seat (14), a lower joint (16) and a locking ring seat (17) in sequence along an axial direction thereof, the sealing barrel (12) is sleeved inside the upper joint (11), used for forming a seal with a sealing head (23) of the negative pressure plug-removing working core (200), the negative pressure pipe (13) is sleeved outside the sealing barrel (12), a lower end thereof is connected with the bridge (15) inside the bridge seat (14), the bridge (15) is provided with the bypass hole (152) and the side hole (153) which are isolated from each other, a second through hole (141) is formed in a side wall of the bridge seat (14), and is communicated with the side hole (153) of the bridge (15), the locking ring seat (17) is arranged at a right end of the bridge (15), and is provided with a locking ring (18) mounted thereon.

2. The integrated sand plug breaking and formation squeeze packer sand control string of claim 1, wherein, The jet pump structure comprises sequentially connected liquid inlet pipes (22), nozzles (25), throat pipes (27) and diffusion pipes (29), and the negative pressure zone is formed in the negative pressure pipe (13) communicated with the throat pipe (27).

3. The integrated sand plug breaking and formation squeeze packer sand control string of claim 2, wherein, The negative pressure unblocking working core (200) is coaxially provided with a capturing head (21), a liquid inlet pipe (22), a sealing head (23), a nozzle seat (24) and a nozzle (25), a throat seat (26), a diffusion pipe (29) and a liquid outlet pipe (210) in sequence along the axial direction; the liquid inlet pipe (22) constitutes a liquid inlet channel of the Venturi jet assembly, the left end of which is sleeved with the capturing head (21), the right end of which extends to the inside of the sealing head (23) and is provided with the nozzle seat (24), and the nozzle seat (24) is connected with the nozzle (25); the throat seat (26) is sleeved in the right end of the sealing head (23), and a throat (27) downstream of the nozzle (25) is installed in the throat seat (26), and the right end of the throat (27) is connected with a throat extension pipe (28); the diffusion pipe (29) is sleeved outside the throat seat (26), and the right end of the diffusion pipe (29) is connected with the liquid outlet pipe (210), and a first opening (2101) is formed in the pipe wall of the liquid outlet pipe (210); the nozzle (25) is used for accelerating the power liquid to form a negative pressure in the area of the throat (27); the sealing head (23) is provided with a liquid suction hole (231) for guiding the formation fluid into the negative pressure area.

4. The integrated sand plug breaking and formation squeeze packer sand control string of claim 3, wherein, When the negative pressure unblocking working core (200) is docked in the negative pressure unblocking working barrel (100), the first opening (2101) on the liquid outlet pipe (210) is aligned and communicated with the side hole (153) and the second opening (141) of the bridge (15), and together constitutes an unblocking outlet channel of the mixed fluid flowing to the oil jacket annulus.

5. An integrated process for negative pressure un-plugging and formation squeeze packer sand control using the integrated tubular string of any one of claims 1-4, wherein, The process comprises the following steps: S1. Tubing string running and setting: connecting the tubing string and running into the well to the designed depth, setting the packer (500) to seal the oil jacket annulus; S2. Negative pressure unblocking operation: pumping the power liquid into the tubing (300), the power liquid drives the jet pump structure in the negative pressure unblocking working core (200) to generate negative pressure, and the formation fluid is sucked and discharged to the oil jacket annulus after mixing and then returned to the ground through the unblocking outlet channel; S3. Washing out the negative pressure unblocking working core: lifting the tubing string to unseal the packer (500), and performing reverse circulation washing from the casing (400) to wash out the negative pressure unblocking working core (200) from the wellbore; S4. Closing the unblocking channel: putting the put-in closing member into the tubing (300), and pumping the liquid to pressurize, so that the closing member is set in the negative pressure unblocking working barrel (100) to block the unblocking outlet channel; S5. Sand washing operation: pumping the liquid from the casing (400) to perform reverse circulation washing to complete the sand washing operation; S6. Sand control operation: lifting the tubing string to the sand control design position to perform formation squeeze packing sand control operation.

6. The integrated process of claim 5, wherein, In step S3, before performing the reverse circulation washing from the casing (400), a catcher is installed at the wellhead to capture and recycle the washed-out negative pressure unblocking working core (200), and the put-in closing member in step S4 is a closing sliding sleeve matched with a steel ball.

7. The integrated process of claim 5, wherein, In step S4, the liquid is pumped to a predetermined pressure to set and lock the closing sliding sleeve.

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