Flow control water device, fracturing water control unit, pipe string and fracturing water control completion method

Abstract

The application provides a flow-regulating and water-controlling device, a fracturing water-controlling unit, a pipe column and a fracturing water-controlling well completion method. The flow-regulating and water-controlling device comprises a base pipe which is configured with a central flow channel; a screen pipe which is sleeved on the base pipe and forms an annular space between the screen pipe and the base pipe; a working cylinder which is fixedly connected to the lower end of the base pipe and communicates with the central flow channel, the working cylinder being provided with a through hole; a protection cylinder which is sleeved on the working cylinder and forms an installation cavity between the protection cylinder and the working cylinder; and a negative pressure flow-regulating controller which is arranged in the installation cavity, the negative pressure flow-regulating controller being provided with an inlet channel and an outlet channel, the inlet channel communicating with the installation cavity and the outlet channel communicating with the working cylinder through the through hole; wherein an oil-water mixture in a formation enters the annular space through the screen pipe, enters the installation cavity and the negative pressure flow-regulating controller, and then enters the central flow channel of the base pipe through the negative pressure flow-regulating controller.

Description

Technical Field

[0001] This invention belongs to the field of ultra-deep horizontal well completion engineering technology, specifically relating to a unidirectional multi-stage heavy oil water control system for ultra-deep horizontal wells. Background Technology

[0002] In recent years, with the continuous exploration and development of various oil and gas fields, "water flooding" often occurs in the later stages of production of oil wells located in bottom-water reservoirs. These types of oil wells often use horizontal wells to maximize reservoir production. Due to the large contact area between the horizontal well and the reservoir, formation friction and changes in reservoir properties often lead to uneven fluid supply in different production sections of the horizontal well. Bottom water tends to concave towards the heel of the horizontal well. Once "water flooding" occurs, it will directly lead to the well being abandoned. The subsequent use of "water shut-off technology" not only increases operating costs but also seriously reduces the development efficiency of the oil well, which is very detrimental to the long-term efficient development of oil and gas fields.

[0003] To address the urgent need for "efficient water control and long-term oil production" in bottom-water developed oil reservoirs, and with the continuous advancement of well completion technology and further improvement in the machining and manufacturing level of downhole tools, water-controlled oil production completion technology has shifted from the initial indirect water control of "variable density perforation completion technology" to direct water control of "flow regulation water control completion technology." The key tool in this flow regulation water control technology is the flow regulation water control device. On the one hand, due to limitations in tool structure and process scope, the water control device only serves as a production channel and cannot be used as a fracturing channel. It is only suitable for oil and gas wells that rely on formation energy for self-flowing or mechanical pumping production, and is not suitable for oil and gas wells that simultaneously require staged acid fracturing and water control oil production. On the other hand, this water control device is often used in light oil wells, and its applicability to heavy oil reservoirs in Northwest China is still unknown.

[0004] Therefore, to achieve efficient development of this type of heavy oil and gas reservoir, a pressing issue that needs to be addressed is water control and oil production after open-hole staged completion of horizontal wells. Conventional water control tools for open-hole staged completion, namely switch sleeves, involve running coiled tubing to close the switch sleeve once water is encountered in a section. However, for horizontal wells with a slope depth exceeding 7000m and a vertical depth exceeding 6500m, coiled tubing operations are high-risk and costly; if obstruction or jamming occurs, it could directly lead to the abandonment of the oil and gas well. Therefore, this type of technology is not suitable for large-scale development of ultra-deep horizontal wells.

[0005] Chinese patent document CN203978405 U discloses a flow regulation and water control device and oil production system. This device and system include a central pipe, a screen assembly, a water control assembly, and a channel located outside the central pipe and connected to it via the water control assembly. Fluid flowing into the central pipe must pass through the screen assembly and the water control assembly sequentially, thus achieving the functions of filtering impurities and regulating fluid flow rate. However, the fluid in this device can both flow in and out, making it impossible to achieve unidirectional control of the fluid flow direction. During reservoir fracturing, once the packer is set, the flow regulation and water control device remains in communication with the formation, making it impossible to simultaneously achieve reservoir fracturing and water control oil production.

[0006] Chinese patent document CN2019195372 U discloses a flow regulation and water control screen pipe. This flow regulation and water control screen pipe needs to be used in conjunction with a switch sleeve. Once water is encountered in a certain section, coiled tubing must be run in to close the switch sleeve of that section. Although it can be used in conjunction with the switch sleeve for sand control and flow regulation and water control, the operation of coiled tubing in ultra-deep wells is risky and costly. Once it encounters obstruction or jamming, it may directly lead to the abandonment of the oil and gas well. Moreover, multi-stage flow regulation and water control is difficult, and the oil production efficiency is greatly limited. Summary of the Invention

[0007] To address the technical problems mentioned above, this invention aims to propose a flow control and water control device, a fracturing and water control unit, a tubing string, and a fracturing and water control well completion method. It integrates the functions of segmented fracturing, sand control, oil stabilization, and water control, enabling segmented fracturing construction and multi-stage water control for heavy oil production. This significantly improves production efficiency and increases waterless oil production.

[0008] Therefore, according to a first aspect of the present invention, a flow regulation and water control device is provided, comprising: a base pipe having a central flow channel; a screen pipe fitted onto the base pipe, forming an annular space between the screen pipe and the base pipe; a working cylinder fixedly connected to the lower end of the base pipe and communicating with the central flow channel, the working cylinder having a through hole; a protective cylinder fitted onto the working cylinder, forming an installation cavity between the protective cylinder and the working cylinder; and a negative pressure flow regulation controller disposed in the installation cavity, the negative pressure flow regulation controller having an inlet channel and an outlet channel, the inlet channel communicating with the installation cavity, and the outlet channel communicating with the working cylinder through the through hole; wherein, an oil-water mixture in the formation enters the annular space through the screen pipe, enters the installation cavity and then enters the negative pressure flow regulation controller, and further enters the central flow channel of the base pipe through the negative pressure flow regulation controller.

[0009] In one embodiment, a one-way valve is also provided in the mounting cavity. The one-way valve includes a base and a plug ball. The one-way valve is configured to allow fluid within the annular space to flow only to the negative pressure flow controller.

[0010] In one embodiment, the outer wall of the working cylinder is provided with an annular groove, and the annular groove and the protective cylinder surround to form the mounting cavity.

[0011] In one embodiment, the negative pressure flow controller is configured as an oil phase vortex channel including multiple layers of water phase vortex channels and multiple interconnected adjacent water phase vortex channels, wherein the multiple layers of water phase vortex channels are distributed in concentric circles, the outermost water phase vortex channel is tangent to the inlet channel, and the outlet channel is located at the center of the concentric circles.

[0012] In one embodiment, a plurality of circumferentially distributed external negative pressure generating protrusions are provided on the inner wall surface of the radially outer side of the water phase vortex channel, and a plurality of circumferentially distributed internal negative pressure generating protrusions are provided on the inner wall surface of the radially inner side. The internal negative pressure generating protrusions and the external negative pressure generating protrusions are staggered in the circumferential direction, and the oil phase vortex channel passes through the corresponding internal negative pressure generating protrusion.

[0013] According to a second aspect of the present invention, a fracturing water control unit is provided, comprising: a single-flow fracturing sleeve; and a flow regulation and water control device as described above, wherein the flow regulation and water control device is connected to the downstream end of the single-flow fracturing sleeve and communicates with the single-flow fracturing sleeve.

[0014] In one embodiment, the single-flow fracturing sleeve includes: a housing having a fracturing hole penetrating its inner wall; an upper connector and a lower connector respectively connected to both ends of the housing; an inner sliding sleeve concentrically arranged within the housing; a ball seat connected to the upper end of the inner sliding sleeve; and a compression spring disposed between the axial end faces of the inner sliding sleeve and the lower connector; wherein the inner sliding sleeve is configured to initially block the fracturing hole by being fixedly connected to the housing by a shear pin, and can be opened by shearing the shear pin downward by throwing a ball to compress it, thereby performing fracturing operations, and the inner sliding sleeve can be reset under the action of the compression spring after the fracturing operation is completed.

[0015] According to a third aspect of the present invention, a multi-stage fracturing water control string is provided, comprising: a production tubing; a plurality of fracturing water control units as described above, which are sequentially spaced apart and connected in series in the production tubing; and a plurality of packers spaced apart on the production tubing, wherein each fracturing water control unit is correspondingly located between two adjacent packers.

[0016] In one embodiment, the fracturing water control unit is connected to the production tubing via a unit joint.

[0017] According to a fourth aspect of the present invention, a fracturing and water-controlled well completion method is provided, comprising the following steps:

[0018] Run the multi-stage fracturing and water control string as described above, and ensure that all of the fracturing and water control units reach the horizontal well section;

[0019] Insert the setting ball to set all the packers at once;

[0020] The corresponding pressure-absorbing balls are sequentially dropped into the well to fit the corresponding ball seats, and the corresponding fracturing holes in the formation are opened sequentially by pressure-absorbing, thus completing the fracturing operation of the corresponding formation.

[0021] In oil production, heavy oil from the formation flows through the screen pipe into the negative pressure flow controller, and then into the base pipe through the negative pressure flow controller;

[0022] The fracturing and water control completion method described above can achieve unidirectional multi-stage water control in heavy oil.

[0023] Compared with the prior art, the advantages of this application are:

[0024] The flow control and water management device of the present invention employs a one-way valve, enabling unidirectional fracturing while providing a fluid flow channel for subsequent unidirectional oil production. By utilizing a negative pressure flow controller, the device is suitable for heavy oil reservoirs, significantly extending the waterless production period, increasing waterless oil production, and greatly improving production efficiency. Furthermore, the device uses high-precision composite screens, greatly improving sand control and preventing sand particles from clogging oil and gas channels and affecting production. With combinations of one-way valves of different inner diameters, and in conjunction with open-hole packers, open-hole unidirectional segmented fracturing is achieved, maximizing the release of production capacity from each reservoir. With multiple fracturing and water management units combined, water control and oil production can be implemented in each segment, achieving multi-stage water control and oil production in heavy oil, greatly improving production efficiency. The multi-stage fracturing and water management tubing of the present invention integrates segmented fracturing, sand control, and oil stabilization and water control functions, forming an integrated segmented fracturing-water control completion technology suitable for ultra-deep horizontal wells. The fracturing and water control completion method of the present invention can effectively solve the problems of premature water encounter during the production of heavy oil blocks and the inability of existing water control tools to perform reservoir fracturing, thus significantly improving production efficiency. Attached Figure Description

[0025] The present invention will now be described with reference to the accompanying drawings.

[0026] Figure 1 The structure of the multi-stage fracturing water control string according to the present invention is schematically shown.

[0027] Figure 2 schematically shown Figure 1 The structure of the single-flow fracturing sliding sleeve in the multi-stage fracturing water control tubing is shown.

[0028] Figure 3 schematically shown Figure 1The structure of the flow control and water regulation device in the multi-stage fracturing water control tubing string is shown.

[0029] Figure 4a and Figure 4b schematically shown Figure 3 The structure of the connecting joint in the flow control and water regulation device shown.

[0030] Figure 5a schematically shown Figure 3 The structure of the working cylinder in the flow control and water regulation device shown.

[0031] Figure 5b and 5c They were displayed respectively Figure 5a Sectional views of line BB and line CC.

[0032] Figure 6a and 6b schematically shown Figure 3 The structure of the negative pressure flow control controller in the flow control device shown.

[0033] Figure 7a and Figure 7b schematically shown Figure 3 The structure of the one-way valve in the flow control device is shown.

[0034] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0035] The invention will now be described with reference to the accompanying drawings.

[0036] In this application, it should be noted that the end of the unidirectional multi-stage heavy oil water control system for ultra-deep horizontal wells that is lowered into the wellbore and closer to the wellhead is defined as the upper end or a similar term, and the end that is further from the wellhead is defined as the lower end or a similar term.

[0037] Figure 1 The structure of the multi-stage fracturing water control string 100 according to the present invention is schematically shown. For example... Figure 1 As shown, the multi-stage fracturing water control string 100 includes a production tubing 2 for running into the open hole wellbore 1, multiple fracturing water control units connected in series with spacing between them in the production tubing 2, and multiple packers 5 spaced apart on the production tubing 2. The fracturing water control units are located in the horizontal well section, and each fracturing water control unit is located between two adjacent packers 5.

[0038] In one embodiment, the fracturing water control unit is connected to the production tubing 2 via unit connector 6.

[0039] According to the present invention, the fracturing water control unit includes a single-flow fracturing sliding sleeve 3 and a flow regulation and water control device 4. For example... Figure 1 As shown, the flow control device 4 is connected to the downstream end of the single-flow fracturing sleeve 3 and is in communication with the single-flow fracturing sleeve 3. During construction, the fracturing water control units are all lowered into the horizontal well section of the ultra-deep well to realize multi-stage segmented fracturing operations and multi-stage water control of the reservoir.

[0040] Figure 2 The structure of the single-flow fracturing sliding sleeve 3 is schematically shown. For example... Figure 2 As shown, the single-flow fracturing sleeve 3 includes a cylindrical outer shell 30, an upper connector 34 and a lower connector 39 connected to both ends of the outer shell 30, an inner sliding sleeve 35 concentrically arranged within the outer shell 30, a ball seat 32 fixedly connected to the upper end of the inner sliding sleeve 35, and a compression spring 38 disposed between the axial end faces of the inner sliding sleeve 35 and the lower connector 39. The outer shell 30 has fracturing holes 301 penetrating its inner wall. Preferably, there are multiple fracturing holes 301, evenly distributed circumferentially. In the initial state, the inner sliding sleeve 35 is fixedly connected to the outer shell 30 by shear pins 33, sealing the fracturing holes 301. At this time, the single-flow fracturing sleeve 3 is in the closed state. When fracturing is required, pressure-pressurizing balls of appropriate sizes are sequentially dropped into the wellhead. After the different sizes of pressure-pressurizing balls are matched with their corresponding ball seats 32, the pressure-pressurizing process causes the inner sliding sleeve 35 to shear the shear pins 33 and descend, compressing the telescopic spring 38 to open the fracturing hole 301. Then, a pump truck is used to inject fracturing fluid into the tubing to complete the fracturing of the corresponding formation. After the fracturing operation is completed, the inner sliding sleeve 35 can return to its original position under the action of the compression spring 38.

[0041] In one embodiment, both the upper connector 34 and the lower connector 39 are constructed with threaded connections. The upper connector 34 is fixedly connected to the unit connector 6 via a threaded connection, thereby forming a connection with the production oil pipe 2. The lower connector 39 is fixedly connected to the flow control and water regulation device 4 via a threaded connection.

[0042] like Figure 2 As shown, the upper part of the lower connector 39 is inserted into the housing 30, and the upper end face of the lower connector 39 is radially inside the housing 30, thus forming a first step with the end face facing upward on the inner wall of the housing 30. At the same time, the outer wall of the inner sliding sleeve 35 is constructed with a second step with the end face facing downward. The two ends of the telescopic spring 38 abut against the first step and the second step, respectively.

[0043] To ensure a tight seal between the lower connector 39 and the outer casing 30, a plurality of first sealing elements are provided at the connection between the lower connector 39 and the outer casing 30. The first sealing elements can be, for example, sealing rings. At the same time, to ensure the sealing of the fracturing hole 301, second sealing elements 36 and corresponding retaining rings 37 are provided between the inner sliding sleeve 35 and the outer casing 30, which are axially spaced from each other. In the initial state, the fracturing hole 301 is located between the second sealing elements axially.

[0044] According to the present invention, such as Figure 3 As shown, the flow control device 4 includes a base pipe 50, a screen pipe 49, a working cylinder 41, a protective cylinder 43, and a negative pressure flow controller 42. The base pipe 50 has a central flow channel. The screen pipe 49 is fitted onto the base pipe 50, forming an annular space between the screen pipe 49 and the base pipe 50. The working cylinder 41 is fixedly connected to the lower end of the base pipe 50, and its internal channel communicates with the central flow channel of the base pipe 50. The working cylinder 41 has a through hole 410 penetrating the sidewall. The protective cylinder 43 is fitted onto the working cylinder 41, forming an installation cavity between the protective cylinder 43 and the working cylinder 41. The upper end of the protective cylinder 43 is fixedly connected to the screen pipe 49. The negative pressure flow controller 42 is disposed within the installation cavity. The negative pressure flow controller 42 has an inlet channel 16 and an outlet channel 21. The inlet channel 16 communicates with the installation cavity, and the outlet channel 21 communicates with the internal channel of the working cylinder 41 through the through hole 410, and further communicates with the central flow channel of the base pipe 50. The reservoir fluid enters the wellbore and is filtered by the screen pipe 49 before entering the annular space. It then enters the installation cavity and passes through the inlet channel 16 into the negative pressure flow controller 42. After being acted upon by the negative pressure flow controller 42, it enters the base pipe 50 through the outlet channel 21.

[0045] In this embodiment, the lower end of the working cylinder 41 ( Figure 3 The left end of the working cylinder 41 is sealed to the protective cylinder 43 by a sealing ring, and the upper end of the working cylinder 41 is sealed to the protective cylinder 43 by a sealing ring. Figure 3 The connection between the right end of the tube and the base tube 50 is sealed with a sealing ring 48.

[0046] According to one embodiment of the present invention, a butt joint 47 is provided between the screen tube 49 and the working cylinder 41, the butt joint 47 being used to connect the screen tube 49 and the working cylinder 41. The base tube 50 and the working cylinder 41 are fixedly connected by threads. Figure 4a and Figure 4b The structure of the mating joint 47 is schematically shown. (For example...) Figure 4a and Figure 4b As shown, the mating joint 47 is cylindrical in shape, and one end of the mating joint 47 ( Figure 4aThe left end of the joint 47 is provided with an external thread for fixed connection with the working cylinder 41. Multiple radially inwardly protruding portions 471 are provided on the inner wall surface of the joint 47. These protruding portions 471 are evenly spaced circumferentially and are located in the same axial position, preferably at the axial center. An annular protrusion 472 extending radially outward is provided on the outer surface of the joint 47. The annular protrusion 472 corresponds to the protruding portions 471 and is located in the same axial position. Meanwhile, at one end of the connecting screen tube 49 ( Figure 3 The outer wall surface of the left end of the middle part is provided with a groove portion (not shown) that can be adapted to multiple protrusions 471 for mating and connection with the mating joint 47.

[0047] According to the present invention, the outer wall surface of the working cylinder 41 is provided with an annular groove, and the annular groove and the protective cylinder 43 surround to form an installation cavity. A through hole 410 is provided on the side wall of the working cylinder 41 corresponding to the annular groove. During installation, the outlet channel 21 of the negative pressure flow controller 42 is aligned with the through hole 410 and then directly welded to the working cylinder 41. Figure 5a As shown, two spaced-apart annular grooves are provided on the outer wall of the working cylinder 41. Thus, the protective cylinder 43 and the annular grooves form an annular mounting cavity. The negative pressure flow controller 42 and the one-way valve 46 (see below) are respectively installed in the two annular mounting cavities.

[0048] Figure 5b and 5c They were displayed respectively Figure 5a Sectional views along line BB and line CC. (e.g.) Figure 5b and 5c As shown, the right sidewall of the annular groove is provided with an opening groove to enable communication between the two annular grooves and the annular space between the screen tube 49 and the base tube 50.

[0049] Figure 6a and 6b The structure of the negative pressure flow controller 42 is schematically shown. For example... Figure 6a and 6b As shown, the negative pressure flow controller 42 is constructed as an oil phase vortex channel 18 comprising multiple layers of water phase vortex channels 17 and multiple interconnected adjacent water phase vortex channels 17. The multiple layers of water phase vortex channels 17 are all circular and concentrically distributed. The outermost water phase vortex channel 17 is tangential to the inlet channel 16 and thus connected, while the outlet channel 21 is located at the center of the concentric circles. Two to five layers of water phase vortex channels 17 can be arranged. The negative pressure flow controller 42 enables the fluid passing through it to generate vortexes and creates different resistances for water and oil in the fluid, thereby controlling the production rate of the fluid in the corresponding reservoir of the horizontal well. This, in turn, adjusts the production profile of the horizontal well, suppresses edge and bottom water coning, delays the water breakthrough time of the horizontal well, and ultimately improves the single-well production and recovery rate.

[0050] like Figure 6a As shown, multiple circumferentially distributed external negative pressure generating protrusions 19 are provided on the inner wall surface of the outermost water phase vortex channel 17 on its radially outer side, while multiple circumferentially distributed internal negative pressure generating protrusions 20 are provided on the inner wall surface of the outermost water phase vortex channel 17 on its radially inner side. The internal negative pressure generating protrusions 19 and the external negative pressure generating protrusions 20 are staggered in the circumferential direction, and the oil phase vortex channel 18 passes through the corresponding internal negative pressure generating protrusion 20.

[0051] There are 3-10 external negative pressure generating protrusions 19 and internal negative pressure generating protrusions 20. The oil phase vortex channel 18 and the water phase vortex channel 17 form an angle of 0-90 degrees. The oil phase vortex channel 18 is located after the external negative pressure generating protrusion 19 and is located in the circumferential middle of the internal negative pressure generating protrusion 20.

[0052] According to the present invention, the flow control device 4 further includes a one-way valve 46. The one-way valve 46 is disposed within the mounting cavity and is configured to allow fluid within the annular space to flow only to the negative pressure flow controller 42. The one-way valve 46 includes a base 44 and a plug ball 45. The base 44 is used to mount the one-way valve 46. Figure 7a and Figure 7b The structure of the one-way valve 46 is schematically shown. (For example...) Figure 7a and Figure 7b As shown, the one-way valve 46 includes a cylindrical body 461. Multiple axially extending and continuous flow channels are provided within the side wall of the cylindrical body, and these flow channels are evenly spaced circumferentially. Each flow channel includes a first flow channel 462 and a second flow channel 463 communicating with the first flow channel 462. The diameter of the first flow channel 462 is larger than the diameter of the second flow channel 463, and the connection between the first flow channel 462 and the second flow channel 463 forms a conical transition. The diameter of the plug ball 45 is larger than the diameter of the second flow channel 463 but smaller than the diameter of the first flow channel 462. Therefore, fluid can only flow from the second flow channel 463 to the first flow channel 462. During manufacturing, the one-way valve 46 is machined into two semi-cylindrical pieces, which are directly joined and locked into the annular mounting cavity during installation.

[0053] The fracturing and water control completion method is described in detail below. During horizontal well fracturing and oil production, the multi-stage fracturing and water control string 100 of this invention is used. The specific construction is as follows:

[0054] First, multiple fracturing water control units are connected to the production tubing 2 as needed to form a production tubing string, which is then lowered into the well along with the production tubing string.

[0055] After that, the setting ball is inserted and all packers are set at once.

[0056] Next, a pressure-locking ball is dropped into the production tubing 2 from the wellhead. Upon reaching the corresponding single-flow fracturing sleeve 3, the ball is intercepted by a ball seat 32 of the appropriate size, forming a dead space. Then, fracturing fluid is injected into the production tubing 2 using a pump truck to complete the fracturing of the corresponding formation. This process continues until all formations have been fracturing. After fracturing is completed, the inner sliding sleeves 35 in each single-flow fracturing sleeve 3 are reset by the corresponding extension springs 38, thereby closing the fracturing orifice 301.

[0057] Heavy oil from the reservoir enters the wellbore annulus, is filtered through screen 49, and then enters the annular space between screen 49 and base pipe 50. After passing through check valve 46, it flows into negative pressure flow controller 42, then into the internal channel of working barrel 41 and the central flow channel of base pipe 50, and finally flows to the wellhead through production tubing 2 for production. The oil-water mixture enters the water phase vortex channel 17 through inlet channel 16 of negative pressure flow controller 42. The water phase vortex channel 17 forces the oil-water mixture to rotate, generating vortex force, and utilizes the difference in density and viscosity between oil and water to separate them. The separated water phase flows along the water phase vortex channel 17 and finally flows out through outlet channel 21. The external negative pressure generating protrusion 19 and the internal negative pressure generating protrusion 20 exert a suction effect on the water in the production channel after the oil-water mixture is accelerated, further increasing the water phase resistance and improving the water phase resistance enhancement effect.

[0058] Due to the presence of the one-way valve 46, reservoir fracturing can be achieved through this fracturing and water control completion method. Multiple sets of flow control units composed of the single-flow fracturing sleeve 3 and the flow control device 4 can achieve multi-stage water control of heavy oil, greatly improving production efficiency. At the same time, it integrates three functions: segmented fracturing, sand control, and oil stabilization and water control, forming an integrated completion technology suitable for ultra-deep horizontal wells with segmented fracturing and water control.

[0059] The flow control and water management device 4 of the present invention employs a one-way valve 46, enabling unidirectional fracturing and providing a fluid flow channel for subsequent unidirectional oil production. The flow control and water management device 4 utilizes a negative pressure flow controller 42, suitable for heavy oil reservoirs, significantly extending the waterless production period, increasing waterless oil production, and greatly improving production efficiency. Furthermore, the flow control and water management device 4 employs a high-precision composite screen pipe, greatly improving sand control and preventing sand particles from clogging oil and gas channels and affecting production. With combinations of one-way valves of different inner diameters, and in conjunction with open-hole packers, open-hole unidirectional segmented fracturing is achieved, maximizing the release of production capacity from each reservoir. With multiple fracturing and water management units combined, water control and oil production can be implemented in each segment, achieving multi-stage water control and oil production in heavy oil, greatly improving production efficiency. The multi-stage fracturing and water management tubing of the present invention integrates segmented fracturing, sand control, and oil stabilization and water control functions, forming a segmented fracturing-water control integrated well completion technology suitable for ultra-deep horizontal wells. The fracturing and water control completion method of the present invention can effectively solve the problems of premature water encounter during the production of heavy oil blocks and the inability of existing water control tools to perform reservoir fracturing, thus significantly improving production efficiency.

[0060] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flow control device, comprising: a base pipe (50) configured with a central flow passage; a screen pipe (49) sleeved on the base pipe, an annular space being formed between the screen pipe and the base pipe; a working cylinder (41) fixedly connected to a lower end of the base pipe and communicating with the central flow passage, the working cylinder being provided with a through hole (410); a protection cylinder (43) sleeved on the working cylinder, an installation cavity being formed between the protection cylinder and the working cylinder; and a negative pressure flow control device (42) arranged in the installation cavity, the negative pressure flow control device having an inlet passage (16) and an outlet passage (21), the inlet passage communicating with the installation cavity, and the outlet passage communicating with the working cylinder through the through hole; wherein an oil-water mixture in a formation enters the annular space through the screen pipe, enters the installation cavity and the negative pressure flow control device, and then enters the central flow passage of the base pipe through the negative pressure flow control device, a one-way valve (46) being further arranged in the installation cavity, the one-way valve including a base (44) and a blocking ball (45), the one-way valve being configured to allow fluid in the annular space to flow only to the negative pressure flow control device, the negative pressure flow control device being configured to include a plurality of water phase cyclone passages (17) and a plurality of oil phase cyclone passages (18) communicating adjacent water phase cyclone passages, wherein the plurality of water phase cyclone passages are arranged in concentric circles, an outermost water phase cyclone passage being tangent to the inlet passage, the outlet passage being arranged at a center of the concentric circles, a plurality of outer negative pressure generating bosses (19) being arranged on an inner wall surface on a radially outer side of the outermost water phase cyclone passage, and a plurality of inner negative pressure generating bosses (20) being arranged on an inner wall surface on a radially inner side, the inner negative pressure generating bosses and the outer negative pressure generating bosses being distributed in a circumferential direction in a staggered manner, and the oil phase cyclone passages passing through the corresponding inner negative pressure generating bosses.

2. The flow-regulating water device of claim 1, wherein An outer wall surface of the working cylinder is provided with an annular groove, the annular groove and the protection cylinder surrounding the installation cavity.

3. A fracturing water control unit, comprising: a single-flow fracturing sliding sleeve (3) ； the flow control device according to claim 1 or 2, the flow control device being connected to a downstream end of the single-flow fracturing sliding sleeve and communicating with the single-flow fracturing sliding sleeve.

4. The frac water control unit of claim 3, wherein, the single-flow fracturing sliding sleeve including: an outer shell (30) provided with a fracturing hole (301) penetrating an inner wall thereof; an upper joint (34) and a lower joint (39) connected to two ends of the outer shell, respectively; an inner sliding sleeve (35) concentrically arranged in the outer shell; a ball seat (32) connected to an upper end of the inner sliding sleeve; and a compression spring (38) arranged between the inner sliding sleeve and an axial end surface of the lower joint; The inner sliding sleeve is configured to be fixedly connected with the outer shell by a shear pin (33) in an initial state to block the fracturing hole, and to be sheared down by a ball to open the fracturing hole to perform fracturing operation, and the inner sliding sleeve can be reset under the action of the compression spring after the fracturing operation is completed.

5. A multi-stage fracturing water control pipe string, comprising: a production tubing (2); a plurality of fracturing water control units according to claim 4 connected in series in the production tubing; a plurality of packers (5) arranged at intervals on the production tubing, each of the fracturing water control units being arranged between two adjacent packers.

6. The multistage frac water control string of claim 5, wherein, The fracturing water control unit is connected with the production tubing through a unit joint (6).

7. A fracturing water control completion method, comprising the following steps: lowering the multi-stage fracturing water control pipe string according to claim 5 or 6, and making the plurality of fracturing water control units reach the horizontal well section; feeding a setting ball to set all the packers at one time; feeding corresponding size pressure holding balls downhole in sequence to make the pressure holding balls fit the corresponding ball seats, open the fracturing holes of the corresponding formations by pressure holding, and complete the fracturing operation of the corresponding formations; oil production, the heavy oil in the formation flows into the negative pressure flow controller through the screen pipe, and flows into the base pipe through the negative pressure flow controller; wherein the fracturing water control completion method can realize one-way multi-stage heavy oil water control.

Images