Water finding and plugging integrated device and method for oil well

Abstract

The application relates to a water finding and plugging integrated device for an oil well and a production control method, wherein the water finding and plugging integrated device comprises a casing, an isolation assembly, a production assembly and a control assembly; the casing is arranged in a main borehole of the oil well; the isolation assembly is arranged in the casing and is used for isolating an upper water layer and an oil layer; the production assembly comprises a tubing pipe penetrating through the casing and extending into a target branch borehole to form a fluid passage; the control assembly is used for selectively controlling a communication state of the fluid passage to switch different production states; the production states include a state of producing common fluid of all branch boreholes, a state of producing fluid of the target branch borehole and a state of producing fluid of branch boreholes except the target branch borehole; the water finding and plugging integrated device switches different production states through the control assembly, and judges water sources according to water content of produced liquid under different production states.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to an integrated water-finding and plugging device and a controlled extraction method for oil wells. Background Technology

[0002] Multi-branch oil wells are oil wells with two or more branches drilled from the same well. They can encounter different reservoirs or different locations within the same reservoir, thereby increasing the drainage area and single-well production. However, multi-branch oil wells face complex water flooding problems, with both complex water sources and significant difficulties in finding water sources. Summary of the Invention

[0003] This invention provides an integrated device for finding and plugging water in oil wells and a controlled production method.

[0004] The technical solution adopted by this invention to solve its technical problem is: to construct an integrated water-finding and plugging device for oil wells, comprising: Casing, used to be installed in the main wellbore of an oil well; An isolation assembly is disposed within the casing and configured to isolate the upper water and oil layers surrounding the well. Production components, including tubing that passes through the casing and is configured to extend into a target branch wellbore of the well to form a fluid passage; A control component is used to selectively control the connectivity of the fluid channels to switch between different production states; the production states include the state of producing common fluid from each branch wellbore, the state of producing fluid from the target branch wellbore, and the state of producing fluid from the remaining branch wellbores excluding the target branch wellbore. The integrated water-finding and blocking device is configured to switch between different production states through the control component and determine the source of water based on the water content of the liquid produced under different production states.

[0005] In some embodiments, the isolation assembly includes a blind tube disposed at the junction of the upper water layer and the oil layer, the blind tube being disposed within the casing and forming an annular channel between it and the inner wall of the casing; The isolation assembly also includes a sealing structure that blocks the upper and lower ends of the annular channel.

[0006] In some embodiments, the production assembly further includes a perforated pipe with perforations in its wall; one end of the perforated pipe is disposed at the lower part of the isolation assembly, and the other end is disposed at the target branch well; a portion of the tubing is disposed in the perforated pipe.

[0007] In some embodiments, the control component includes two sliding sleeves fitted onto the tubing and configured in the casing and the target branch wellbore, the sliding sleeves being configured to control the communication state between the inside of the tubing and / or the circumferential outside of the tubing and the upper delivery path of the tubing.

[0008] In some embodiments, the integrated water-finding and plugging device further includes a sealing assembly for forming multiple sealing positions between the casing and the tubing; among the multiple sealing positions, there are positions located above the sliding sleeve of the casing and positions located on the side of the sliding sleeve away from the wellbore in the target branch wellbore.

[0009] In some embodiments, the production assembly further includes a perforated pipe with perforations in its wall; one end of the perforated pipe is disposed at the lower part of the isolation assembly, and the other end is disposed at the target branch well; a portion of the tubing is disposed in the perforated pipe; The packer assembly includes a fourth packer and a fifth packer for placement in the target branch wellbore. The fourth packer is installed between the perforated tubing and the target branch wellbore. The fifth packer is installed between the tubing and the perforated tubing and is positioned opposite to the fourth packer in the circumferential direction of the tubing.

[0010] This invention also constructs a controlled extraction method, employing the aforementioned integrated water-finding and blocking equipment, wherein the controlled extraction method includes: The integrated water-finding and plugging equipment is lowered into the oil well, the isolation component is placed at the junction of the upper water layer and the oil layer, and the production component is configured in the target branch wellbore. By controlling the control components to switch production states, at least one branch wellbore can participate in production. The water content of the produced fluid under each state is detected and judged in turn, and the source of the water is investigated and determined. Based on the source of the water, the oil well is used for extraction.

[0011] In some embodiments, the step of switching production states by controlling the control component to enable different combinations of branch wells to participate in production, synchronously detecting the water cut of the produced fluid in each state, and investigating and determining the source of the water production specifically includes: The control component is controlled to be in a first production state, so that each branch wellbore participates in production, and the water content of the produced liquid in the first production state is detected. Based on the moisture content in the first production state, determine whether the upper water layer is the source of the water output; When it is determined that the upper water layer is not a source of water production, the control component is switched to the second production state, so that the target branch wellbore produces independently, and the water content of the produced liquid in the second production state is detected. Based on the water cut in the second production state, it is determined whether the water source is from the target branch well or the remaining branch well.

[0012] In some embodiments, determining whether the upper water layer is a source of effluent based on the moisture content in the first production state specifically includes: The moisture content in the first production state is compared with the moisture content before the integrated water-finding and blocking equipment is lowered. When the moisture content in the first production state decreases to the level of the water-finding and blocking equipment before it is lowered to the level of the preset condition, it is determined that the water originates from the upper water layer. When the moisture content in the first production state does not decrease to the level of the preset condition, it is determined that the upper water layer is not the source of the water. And / or, based on the water cut in the second production state, determine whether the water source originates from the target branch well or the remaining branch wells, specifically including: The water cut in the second production state is compared with the water cut before the integrated water-finding and plugging equipment is installed. When the water cut in the second production state decreases to the level of the water cut before the integrated water-finding and plugging equipment is installed, the water is determined to originate from the remaining branch wellbore. When the water cut in the second production state does not decrease to the level of the preset condition, the water is determined to originate from the target branch wellbore.

[0013] In some embodiments, when an oil well has three or more branch wellbores, after determining that the upper water layer is not a source of water production, the tubing is sequentially arranged in different branch wellbores, so that each branch wellbore produces independently, and the water content change of the produced liquid under different production conditions is compared to determine the source of water production.

[0014] The implementation of this invention has the following beneficial effects: This integrated water-finding and plugging equipment can effectively isolate the upper water layer and oil layer, avoiding the problem of upper water layer leakage in advance. By selectively producing fluid from all branch wells or the target branch well, the source of water production can be determined, which is beneficial for exploiting areas with higher crude oil concentrations. This solution reduces the number of tubing trips, lowers construction complexity and operating costs, and can adapt to multi-branch wells, exhibiting strong applicability. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a longitudinal sectional view of an embodiment of the integrated water-finding and plugging device of the present invention being lowered into an oil well, showing only the structures related to the integrated water-finding and plugging device.

[0016] Figure label: Upper water layer 1; oil layer 2; first branch wellbore 3; second branch wellbore 4; casing 5; tubing 6; perforated pipe 7; blind pipe 8; first packer 9; second packer 10; third packer 11; fourth packer 12; fifth packer 13; first sliding sleeve 14; second sliding sleeve 15. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0018] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0020] This invention constructs an integrated water-finding and plugging device, applicable to oil and gas wells containing oil wells. The oil well includes a main wellbore and at least one branch wellbore. In some embodiments, the oil well includes a main wellbore and multiple branch wellbores; the multiple branch wellbores can be arranged at intervals along the longitudinal direction of the oil well, or distributed along the circumferential or transverse direction of the oil well, or arranged in a multi-level branching, fishbone, radial, or other complex manner.

[0021] refer to Figure 1 The integrated water-finding and plugging equipment mainly includes casing 5, isolation components, production components, and control components. Through the cooperation of these components, the upper water layer 1, oil layer 2, and different branch wellbores can be effectively isolated. By selectively producing fluids in different channels, the source of water production can be determined, and areas with higher crude oil concentrations can be extracted.

[0022] The casing 5 is configured to be placed inside the oil well to reinforce the wellbore, isolate the formation, and form a downhole fluid passage. Specifically, the casing 5 is placed in the main borehole of the oil well.

[0023] The isolation assembly is configured to be disposed within the casing 5 and is used to isolate the upper water layer 1 and the oil layer 2. The isolation assembly may include a blind pipe 8 and a packer structure that mates with the blind pipe 8 (see reference). Figure 1 (The second packer 10 and the third packer 11 are shown). The blind pipe 8 can be set at the junction of the upper water layer 1 and the oil layer 2 to block the crossflow path between the upper water layer 1 and the oil layer 2. The blind pipe 8 can be a tubular structure with a certain gap between it and the inner wall of the casing 5 to form an annular channel; by sealing the upper and lower ends of the annular channel with the packer structure, the blind pipe 8 can form a reliable isolation section at the corresponding position, thereby reducing the possibility of fluid from the upper water layer 1 entering the oil layer production channel.

[0024] The production assembly is configured to create at least two selectable fluid channels in the well. The production assembly may include a perforated pipe 7 and tubing 6. The perforated pipe 7 extends at least partially into the corresponding branch wellbore (hereinafter referred to as the target branch wellbore into which the production assembly extends). The wall of the perforated pipe 7 has perforations to allow fluid communication between the inside and outside of the perforated pipe 7. One end of the tubing 6 is positioned on a platform or at ground level, and the other end is located within the perforated pipe 7. The interior of the tubing 6 forms a first production channel, and the external space of the tubing 6 forms a second production channel. Through independent or combined production via the first and second production channels, fluid analysis can be performed to differentiate between different areas or different branch wellbores.

[0025] The control component is configured to selectively control the connectivity of different production channels. The control component may include at least two sliding sleeves fitted onto the oil pipe 6 (see reference). Figure 1The first sliding sleeve 14 and the second sliding sleeve 15 shown are respectively arranged in the casing 5 and the target branch wellbore. The sliding sleeve is a downhole tool whose on / off state can be remotely controlled. It can be remotely operated from the ground through electrical control, hydraulic control, pressure pulse control or other means, so as to adjust the flow state of the formation without running the tubing string.

[0026] The sliding sleeve has at least two switching valves. The first switching valve is used to connect / disconnect the external environment of the oil pipe 6 with the upper transport path of the oil pipe 6, and the second switching valve is used to connect / disconnect the internal environment of the oil pipe 6 with the upper transport path of the oil pipe 6. Thus, the sliding sleeve can switch between at least three states: a first state where the first switching valve is closed and the second switching valve is open, to produce fluid only inside the oil pipe 6; a second state where the first switching valve is open and the second switching valve is closed, to produce fluid only outside the oil pipe 6; and a third state where both the first and second switching valves are open simultaneously, to produce fluid simultaneously inside and outside the oil pipe 6.

[0027] Additionally, the integrated water-blocking and sealing device may also include a packer assembly configured to form multiple packer locations between the casing 5 and the tubing 6, to better create independent or selectively connected fluid zones. The packer assembly may include multiple packers (see reference). Figure 1 The first packer 9, the fourth packer 12, and the fifth packer 13 shown are respectively positioned between the casing 5 and the tubing 6, in the upper region of the sliding sleeve arranged in the casing 5; between the perforated pipe 7 and the casing 5, in the sliding sleeve arranged in the branch wellbore on the side away from the wellbore; and between the tubing 6 and the perforated pipe 7, in the sliding sleeve arranged in the branch wellbore on the side away from the main wellbore, to block the flow of non-target fluids and clarify the fluid source between different production channels. The packing structure used in the above isolation components can also be a packer.

[0028] Through the above structure, the integrated water-finding and shut-off equipment can create an isolation zone and a controllable production channel downhole. On the one hand, the isolation component can reduce cross-flow between the upper water layer 1 and the oil layer 2; on the other hand, the control component can selectively produce fluids inside the tubing 6, outside the tubing 6, and in different branch wellbores without frequent tubing string tripping, which can not only identify the source of water production but also exploit areas with higher crude oil concentrations.

[0029] Furthermore, this invention also provides a controlled production method, which enables production testing of at least some branch wells sequentially based on this integrated water-finding and plugging equipment, thereby identifying the source of water production. This controlled production method may include the following steps: The integrated water-finding and plugging equipment is lowered into the oil well, positioning the isolation component between the upper water layer 1 and the oil layer 2, and extending the production component to at least one branch wellbore; in addition, the packer component can be used for setting. By controlling the control components to switch production states, different combinations of branch wells can participate in production. The water content of the produced fluid under each state is detected and judged in turn, and the source of the water is investigated and determined. Based on the source of the water, the oil well is used for extraction.

[0030] Furthermore, the step of switching production states by controlling the control component to enable different combinations of branch wells to participate in production, simultaneously detecting the water cut of the produced fluid in each state, and investigating and determining the source of the water, may specifically include: The control components are in the first production state, enabling multiple branch wells to produce simultaneously and detecting the water cut of the produced fluid; When the moisture content in the first production state is significantly lower than the moisture content before the water-blocking integrated equipment is lowered, it is determined that the water originates from the upper water layer 1. When the water cut does not decrease significantly in the first production state, it indicates that the water produced does not originate from the upper water layer 1. The control components are then switched to the second production state, allowing one of the branch wells to produce independently, and the water cut of the produced liquid is detected. If the water cut does not decrease significantly in the second production state, the water is determined to originate from the current branch wellbore. Conversely, if the water cut decreases significantly in the second production state, the water is determined to originate from other branch wellbores that are not involved in the second production state. In this case, the water source can be determined to be a specific isolated branch wellbore using a process of elimination and connectivity. This allows for the location of the water source in the branch wellbore with fewer testing steps. Alternatively, the control components can be switched to test the remaining branch wellbores one by one until the water source is determined.

[0031] The extraction of oil from the well based on the source of the water supply may specifically include: Based on the source of water production, bypass the producing branch well and proceed with the extraction of other branch wells. Understandably, due to the presence of casing 5 and the isolation components, even if the source of water appears in the upper water layer 1, it has been successfully isolated, allowing normal extraction operations to proceed with the branch wells.

[0032] In summary, the integrated water-finding and plugging equipment and method provided by this invention can achieve water-oil layer isolation and selective production in branch wells and tubing channels. By comparing the water content of the produced fluid under different production conditions, the source of water can be quickly determined. This solution reduces the number of tubing trips, lowers construction complexity and operating costs, and is adaptable to multi-branch wells, complex wellbore structures, and different branch arrangements, demonstrating good field applicability.

[0033] Next, with Figure 1 The specific structure and usage of this integrated water-finding and blocking device will be explained using the illustrated embodiment as an example.

[0034] See Figure 1 In this embodiment, the oil well extends downwards, passing through the upper water layer 1 to reach the oil layer 2. The oil well includes a main wellbore and two branch wellbores. Hereinafter, the relatively upper branch wellbore will be referred to as the first branch wellbore 3, and the relatively lower branch wellbore will be referred to as the second branch wellbore 4; wherein, (here, the first branch wellbore 3 is referred to as the target branch wellbore).

[0035] The integrated water-blocking and sealing equipment includes a sleeve 5, an isolation component, a production component, a control component, and a sealing component.

[0036] The casing 5 is installed in the main wellbore. The casing 5 is a tubular steel material that is lowered into the wellbore to reinforce the well wall, isolate the formation, and establish a fluid channel. It can be used with the isolation assembly to seal the leakage level of the upper water layer 1.

[0037] The isolation assembly may include a blind pipe 8, a second packer 10, and a third packer 11. The blind pipe 8 is configured as a tubular member with open ends, no flow holes along its entire length, and a complete pipe wall structure. The blind pipe 8 is coaxially disposed inside the casing 5 and positioned relative to the upper water layer 1 and the oil layer 2. An annular channel is formed between the outer wall of the blind pipe 8 and the inner wall of the casing 5, and the upper and lower ends of the annular channel are sealed by the second packer 10 and the third packer 11 to seal the water hole of the casing shoe installed at the bottom of the casing 5 and to preemptively address the problem of leakage in the upper water layer 1 (if leakage occurs in the upper water layer 1).

[0038] The production assembly may include a perforated pipe 7 and tubing 6. The perforated pipe 7 is a steel pipe with perforations drilled into its wall according to a predetermined pattern, used to filter formation fluids, support the wellbore, and enable communication between the inside and outside of the pipe. The top end of the perforated pipe 7 is connected to the central channel of the blind pipe 8, and the bottom end extends into the first branch wellbore. The diameter of the perforated pipe 7 is smaller than the diameter of the branch wellbore, creating a certain gap between the outer wall of the perforated pipe 7 and the inner wall of the first branch wellbore. This gap creates a flow space and allows communication with the formation fluids within the corresponding branch wellbore. By using the perforated pipe 7, it is possible to ensure that fluids in the first branch wellbore 3 can enter the production channel, while also providing some support to the wellbore and reducing the risk of large particles of sand and gravel entering the production tubing string. The tubing 6 is configured to be run inside the casing 5 to lift the oil, gas, and water mixture produced from the formation to the surface. The top end of tubing 6 can be set on a surface platform or wellhead production equipment, and the bottom end extends into casing 5 and into the first branch wellbore 3, located inside perforated tubing 7. The diameter of tubing 6 is smaller than the diameter of perforated tubing 7, so that there is a certain distance between the outer wall of tubing 6 and the inner wall of perforated tubing 7.

[0039] The control assembly may include two sliding sleeves: a first sliding sleeve 14 and a second sliding sleeve 15. The first sliding sleeve 14 is fitted around the circumference of the tubing 6 and located within the casing 5. The first sliding sleeve 14 can be used to control the connectivity of the production channels inside and outside the tubing 6 in the main wellbore area. The second sliding sleeve 15 is fitted around the circumference of the tubing 6 and located in the first branch wellbore, used to control fluid production in the first branch wellbore 3. Through the combined control of the first sliding sleeve 14 and the second sliding sleeve 15, different production states can be switched, including full production, production solely in the first branch wellbore 3, or production in the remaining branch wellbores.

[0040] The packer assembly may include several packers. Packers are downhole tools configured to be inserted into an oil well to isolate oil, gas, and water layers, achieving inter-layer isolation. They are set mechanically or hydraulically, causing the packing element (rubber sleeve) to expand and seal the inner wall of the casing 5, thereby blocking fluid flow and establishing an independent pressure system. In this embodiment, the packer assembly includes a first packer 9, a fourth packer 12, and a fifth packer 13. The first packer 9 is installed between the casing 5 and the tubing 6, above the first sliding sleeve 14; the fourth packer 12 is installed between the perforated tubing 7 and the first branch wellbore; the fifth packer 13 is installed between the tubing 6 and the perforated tubing 7, located opposite the fourth packer 12 in the first branch wellbore, and positioned circumferentially opposite to the fourth packer 12 in the tubing 6. Through the cooperation of the fourth packer 12 and the fifth packer 13, fluid production in the first branch wellbore 3 can be more controllable, thereby improving the accuracy of the test results in the first branch wellbore 3.

[0041] In this invention, the blind pipe 8 is positioned between the upper water layer 1 and the oil layer 2, and the upper and lower openings of the annular channel are sealed by the second packer 10 and the third packer 11, forming a relatively reliable isolation structure downhole. The perforated pipe 7 extends into the branch wellbore, supporting the wellbore and filtering formation particles while ensuring that formation fluids enter the production channel. The tubing 6 is positioned inside the perforated pipe 7, creating different production channels inside and outside the tubing 6. The first sliding sleeve 14 and the second sliding sleeve 15 control the flow status of the main wellbore and the branch area, respectively, enabling the integrated water-finding and plugging equipment to quickly switch production conditions under remote surface control. Controlling the first sliding sleeve 14 allows for the separate production of fluid inside the tubing 6, the separate production of fluid outside the tubing 6, or the simultaneous generation of fluids inside and outside the tubing 6. Simultaneously, with the cooperation of the second sliding sleeve 15, fluid production in the first branch wellbore 3 and / or other branch wellbores can be controlled. Multiple packers are arranged at key gap positions to prevent fluid mixing in different areas and improve the accuracy of test results.

[0042] The following is combined Figure 1 The illustrated embodiments and environmental data illustrate this controlled sampling method.

[0043] Figure 1The target layer shown is a structural trap, edge water oil layer 2, located at a depth of 3620m. The reservoir's average porosity ranges from 11.9% to 15.1%, and its permeability ranges from 76.9% to 219.9 mD, classifying it as a low-porosity, medium-low-permeability reservoir. The surface crude oil density ranges from 0.802% to 0.838 g / m³, classifying it as light oil. The formation crude oil viscosity is 0.9 mPa·s, classifying it as low-viscosity crude oil. Oil layer 2 was developed using multi-branch wells, achieving a water cut of 98% after production, but the source of the water production is uncertain. Analysis suggests the following possible sources: poor cementing quality, resulting in a void between the casing 5 and the formation, causing the upper water layer 1 to flow into oil layer 2 through the outside of the casing 5; or, the water originating from one of the multi-branch wells.

[0044] Based on this, the integrated water-blocking and water-finding equipment is lowered in, and through the combined action of blind pipe 8, second packer 10 and third packer 11, the upper water layer 1 is separated from the oil layer 2.

[0045] Then, the first sliding sleeve 14 is adjusted to produce fluid inside and outside the oil pipe 6 simultaneously, and the second sliding sleeve 15 is opened to allow all branches to produce fluid together. Determine whether the water cut has decreased significantly at this time; if it has decreased significantly, it means that the water comes from the upper water layer 1; if it remains unchanged, adjust the first sliding sleeve 14 to produce the fluid inside the tubing 6 separately, and open the second sliding sleeve 15 to produce the fluid of the first branch wellbore 3 separately. Next, determine whether the water cut has decreased significantly. If it remains unchanged, it indicates that the water comes from the first branch wellbore 3. If it decreases significantly, it indicates that the water comes from the second branch wellbore 4.

[0046] Finally, based on the obtained water source, the other branch wells are exploited instead of the branch wells that produce water.

[0047] It should be noted that whether the water cut has decreased significantly or remained unchanged can be determined based on field experience, reservoir development plan, or preset thresholds. For example, a decrease in water cut reaching a preset percentage or a preset percentage point can be used as a criterion for a significant decrease; fluctuations in water cut less than a preset value can be used as a criterion for no change. The sampling period can be determined based on well conditions, production rate, fluid stabilization time, and testing accuracy requirements.

[0048] The above methods are not limited to the test sequence described above. In other embodiments, production tests can be performed on a single branch well first, followed by joint production tests on all branches; or suspected water-producing branches can be shut down first, and then water cut changes can be observed. As long as different production channels are switched using control components, and the source of water production is determined based on water cut changes under different production states, all of these should fall within the scope of this invention.

[0049] When an oil well has three or more branch wellbores, sliding sleeves and production components can be arranged in the corresponding branch wellbores respectively (for example, using a multi-port joint to configure the tubing 6 as a single-inlet, multi-outlet pipe, and arranging a perforated pipe 7 and a second sliding sleeve 15 in each branch wellbore), or the corresponding sliding sleeves and production components can be arranged in turn in the corresponding branch wellbores. During operation, a joint production test of all branches can be performed first to determine whether the upper water layer 1 is the source of water production; if the upper water layer 1 is not the source of water production, the sliding sleeves of the corresponding branch wellbores can be opened or closed sequentially, allowing each branch wellbore to produce individually or in groups. By comparing the changes in water cut under different production conditions, the source of water production can be determined.

[0050] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. An integrated water-finding and plugging device for oil wells, characterized in that, include: Casing, used to be installed in the main borehole of an oil well; An isolation assembly is disposed within the casing and configured to isolate the upper water and oil layers surrounding the well. Production components, including tubing that passes through the casing and is configured to extend into a target branch wellbore of the well to form a fluid passage; A control component is used to selectively control the connectivity of the fluid channels to switch between different production states; The production status includes the status of producing the common fluid of each branch wellbore, the status of producing the target branch wellbore fluid, and the status of producing the remaining branch wellbore fluid excluding the target branch wellbore. The integrated water-finding and blocking device is configured to switch between different production states through the control component and determine the source of water based on the water content of the liquid produced under different production states.

2. The integrated water-finding and plugging device for oil wells according to claim 1, characterized in that, The isolation assembly includes a blind tube disposed at the junction of the upper water layer and the oil layer, the blind tube being disposed inside the casing and forming an annular channel between it and the inner wall of the casing; The isolation assembly also includes a sealing structure that blocks the upper and lower ends of the annular channel.

3. The integrated water-finding and plugging device for oil wells according to claim 1, characterized in that, The production assembly also includes a perforated pipe with holes in its wall; one end of the perforated pipe is disposed at the lower part of the isolation assembly, and the other end is disposed in the target branch well. A portion of the oil pipe is disposed within the perforated pipe.

4. The integrated water-finding and plugging device for oil wells according to any one of claims 1-3, characterized in that, The control component includes two sliding sleeves fitted on the tubing and configured in the casing and the target branch wellbore, the sliding sleeves being configured to control the communication state between the inside of the tubing and / or the circumferential outside of the tubing and the upper delivery path of the tubing.

5. The integrated water-finding and plugging device for oil wells according to claim 4, characterized in that, The integrated water-finding and plugging equipment also includes a sealing component for forming multiple sealing positions between the casing and the tubing; among the multiple sealing positions, there is a position located above the sliding sleeve of the casing, and a position located on the side of the sliding sleeve in the target branch well that is away from the main well.

6. The integrated water-finding and plugging device for oil wells according to claim 5, characterized in that, The production assembly also includes a perforated pipe with holes in its wall; one end of the perforated pipe is disposed at the lower part of the isolation assembly, and the other end is disposed in the target branch well. A portion of the oil pipe is disposed within the perforated pipe; The packer assembly includes a fourth packer and a fifth packer for placement in the target branch wellbore. The fourth packer is installed between the perforated tubing and the target branch wellbore. The fifth packer is installed between the tubing and the perforated tubing and is positioned opposite to the fourth packer in the circumferential direction of the tubing.

7. A controlled sampling method, characterized in that, Using the integrated water-finding and blocking equipment as described in any one of claims 1 to 6, the controlled extraction method includes: The integrated water-finding and plugging equipment is lowered into the oil well, the isolation component is placed at the junction of the upper water layer and the oil layer, and the production component is configured in the target branch wellbore. By controlling the control components to switch production states, at least one branch wellbore can participate in production. The water content of the produced fluid under each state is detected and judged in turn, and the source of the water is investigated and determined. Based on the source of the water, the oil well is used for extraction.

8. The controlled sampling method according to claim 7, characterized in that, The process involves controlling the control component to switch production states, enabling different combinations of branch wells to participate in production, and simultaneously detecting the water cut of the produced fluid in each state to investigate and determine the source of the water. Specifically, this includes: The control component is controlled to be in a first production state, so that each branch wellbore participates in production, and the water content of the produced liquid in the first production state is detected. Based on the moisture content in the first production state, determine whether the upper water layer is the source of the water output; When it is determined that the upper water layer is not a source of water production, the control component is switched to the second production state, so that the target branch wellbore produces independently, and the water content of the produced liquid in the second production state is detected. Based on the water cut in the second production state, it is determined whether the water source is from the target branch well or the remaining branch well.

9. The controlled sampling method according to claim 8, characterized in that, The step of determining whether the upper water layer is a source of effluent based on the moisture content in the first production state specifically includes: The moisture content in the first production state is compared with the moisture content before the integrated water-finding and blocking equipment is lowered. When the moisture content in the first production state decreases to the level of the water-finding and blocking equipment before it is lowered to the level of the preset condition, it is determined that the water originates from the upper water layer. When the moisture content in the first production state does not decrease to the level of the preset condition, it is determined that the upper water layer is not the source of the water. And / or, based on the water cut in the second production state, determine whether the water source originates from the target branch well or the remaining branch wells, specifically including: The water cut in the second production state is compared with the water cut before the integrated water-finding and plugging equipment is installed. When the water cut in the second production state decreases to the level of the water cut before the integrated water-finding and plugging equipment is installed, the water is determined to originate from the remaining branch wellbore. When the water cut in the second production state does not decrease to the level of the preset condition, the water is determined to originate from the target branch wellbore.

10. The controlled sampling method according to claim 8 or 9, characterized in that, When an oil well has three or more branch wellbores, after determining that the upper water layer is not the source of water production, the tubing is arranged in different branch wellbores in sequence, so that each branch wellbore produces independently, and the water content change of the produced liquid under different production conditions is compared to determine the source of water production.

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