Multilayer Sampling Device and Method for Subsurface Fluids Based on Soluble Spheres

Abstract

This invention discloses a multi-layer underground fluid sampling device based on soluble spheres, comprising a first pipeline and a second pipeline arranged along the depth direction of the monitoring well, and sampling layer pipelines arranged within each fluid sampling layer and connecting the first and second pipelines. Each sampling layer pipeline is equipped with a one-way back pressure valve; the conduction direction of the one-way back pressure valves in odd-numbered layers is opposite to that in even-numbered layers, and the pressure of the one-way back pressure valves sampling on the same side decreases sequentially from the wellhead to the bottom of the well. When sampling in odd-numbered layers, the first pipeline is connected to a nitrogen cylinder, and the second pipeline is connected to a sampling container; the reverse is true for even-numbered layers. A soluble sphere seat is provided between the j-th and j+1-th sampling layer pipelines, with its diameter decreasing sequentially from the wellhead to the bottom of the well. Isolation between adjacent fluid sampling layers is achieved by dropping appropriately sized soluble spheres into the soluble sphere seat. This invention uses only one drive pipe and one sampling pipe, which can reduce the cost of the sampling device while achieving a greater number of sampling layers.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide geological sequestration technology, and in particular to a multi-layer sampling device and method for underground fluids based on soluble spheres. Background Technology

[0002] Carbon dioxide geostorage (CCUS) technology involves capturing carbon dioxide generated during industrial and energy conversion processes before its emission, then transporting it to a storage site via pipelines or ships, compressing it, and injecting it into suitable deep underground strata. Through physical and chemical processes, it is kept isolated from the atmosphere for a long period. Leaks of geostorage carbon dioxide can impact human health and safety, and may also pollute groundwater, increasing its carbon dioxide and heavy metal concentrations. Leaked carbon dioxide entering the soil can affect soil biological systems and plant root systems, altering the ecosystem balance. To ensure the long-term safety and stability of carbon dioxide geostorage, it is essential to monitor underground carbon dioxide levels to determine if leaks have occurred and to provide confidence in the future behavior of carbon dioxide over a longer period. Addressing issues of safety and public trust in carbon dioxide geostorage is crucial for the successful implementation of such projects.

[0003] In response to the problem of carbon dioxide storage leakage monitoring, the current underground fluid stratification sampling device requires the storage container of each layer to be connected to the drive pipe and the sample outlet pipe, which leads to the following problems: (1) Since the space inside the casing is limited after the monitoring well is completed, and each layer in the wellbore requires a drive pipe and a sample outlet pipe, the number of formation fluid sampling layers is limited; (2) The number of drive pipes and sample outlet pipes in the wellbore also directly leads to higher costs for materials and well entry processes of the underground fluid stratification sampling device.

[0004] To address the aforementioned issues, Chinese patent CN112012734A discloses a groundwater sampling device based on a single-hole, multi-layered connection configuration. By optimizing the air intake pipe structure and installing multiple three-way valves and one-way valves at each aquifer, it enables a single air injection pipe to simultaneously drive groundwater from multiple aquifers, minimizing the number of pipes and significantly improving the system's layer-level capacity. However, this patent only combines the gas injection pipe into a single unit, while the fluid sampling pipe still uses one pipe per layer, thus limiting the number of layers from which formation fluid can be sampled, and the sampling device cost remains relatively high.

[0005] Therefore, in order to reduce the cost of sampling devices while achieving a greater number of sampling layers for formation fluids based on U-tubes, it is urgent to propose further improvement schemes to provide technical guarantees for the safe and efficient storage and monitoring of carbon dioxide. Summary of the Invention

[0006] The main objective of this invention is to provide a multi-layer sampling device and method for underground fluids based on soluble spheres. This device uses only one drive tube and one sampling tube, which can reduce the cost of the sampling device and enable more sampling layers of formation fluids based on U-shaped tubes. Furthermore, the device and method are simple in process, easy to use, and highly operable, providing technical support for the safe and efficient monitoring of carbon dioxide sequestration.

[0007] The technical solution adopted in this invention is:

[0008] A multi-layer underground fluid sampling device based on soluble spheres includes a first pipeline and a second pipeline arranged along the depth direction of the monitoring well, and n sampling layer pipelines arranged within each fluid sampling layer and connecting the first pipeline and the second pipeline, where n represents the total number of sampling layers; each sampling layer pipeline is equipped with a one-way back pressure valve, and the conduction direction of the one-way back pressure valve of the i-th layer is opposite to that of the one-way back pressure valve of the j-th layer, i≤n and i is an odd number, j≤n and j is an even number, and the conduction pressure of the one-way back pressure valve sampling on the same side is from the wellhead to... The diameter of the wellhead decreases sequentially from the bottom to the top. When sampling the i-th fluid layer, the first pipeline is connected to a nitrogen cylinder and the second pipeline is connected to a sampling container. When sampling the j-th fluid layer, the first pipeline is connected to a sampling container and the second pipeline is connected to a nitrogen cylinder. A soluble ball seat is provided on the first or second pipeline located between the j-th sampling layer pipeline and the (j+1)-th sampling layer pipeline. The diameter of the soluble ball seat decreases sequentially from the wellhead to the bottom. Isolation between adjacent fluid sampling layers is achieved by depositing soluble balls of appropriate size into the soluble ball seat.

[0009] In the above scheme, a nitrogen valve is provided on the outlet pipeline of the nitrogen cylinder, and the opening and closing of the nitrogen cylinder and the nitrogen pressure are adjusted by the nitrogen valve.

[0010] In the above scheme, a sampling valve is provided on the inlet pipe of the sampling container, and the opening and closing of the sampling container is adjusted by the sampling valve.

[0011] In the above scheme, each fluid sampling layer is equipped with a fluid filter, and the fluid filter is connected to the sampling layer pipeline through a fluid filtration pipeline.

[0012] In the above scheme, a one-way valve is provided on the fluid filtration pipeline.

[0013] In the above scheme, each fluid sampling layer is divided into a formation fluid zone and a cavity zone by a formation fluid isolation plate. The fluid filter is located in the formation fluid zone, and the sampling layer pipeline is located in the cavity zone.

[0014] In the above scheme, each sampling layer pipeline is equipped with a fluid storage container.

[0015] In the above scheme, the soluble spheres are made of metal composite materials. After sampling, they are dissolved through an electrochemical reaction. The dissolution time of each layer of soluble spheres is selected or designed according to the fluid sampling time requirements.

[0016] In the above scheme, the total number of sampling layers n is in the range of 1≤n≤10.

[0017] Accordingly, the present invention also proposes a multi-layer sampling method for underground fluids based on soluble spheres, employing the above-mentioned sampling device, including:

[0018] S1. Dispense a soluble ball into the soluble ball seat located between the j-th sampling layer pipeline and the (j+1)-th sampling layer pipeline, thereby isolating the j-th fluid sampling layer from the (j+1)-th fluid sampling layer; j+1≤n;

[0019] S2. Sample the (j-1)th fluid sampling layer and the jth fluid sampling layer in sequence: When sampling the (j-1)th layer, connect the first pipeline to the nitrogen cylinder and the second pipeline to the sampling container; when sampling the jth layer, connect the first pipeline to the sampling container and the second pipeline to the nitrogen cylinder.

[0020] S3. After the sampling of the j-th layer is completed, the soluble ball between the sampling layer pipeline of the j-th layer and the sampling layer pipeline of the (j+1)-th layer begins to dissolve until it is completely dissolved, so that the fluid sampling layer of the j-th layer is connected to the fluid sampling layer of the (j+1)-th layer.

[0021] S4. Repeat S1-S3, sampling layer by layer from top to bottom;

[0022] S5. When n is odd, the nth fluid sampling layer is sampled last; when n is even, the (n-1)th fluid sampling layer and the nth fluid sampling layer are sampled last.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention, based on the use of soluble balls of different diameters and the special design of the conduction direction and pressure of the one-way back pressure valves on each sampling layer pipeline, enables multiple sampling layers to share a single nitrogen injection pipeline and a single formation fluid sampling pipeline. This saves internal wellbore space, and a single pipeline enables formation fluid sampling at multiple layers, solving the problem of limited sampling layers in current multi-layer sampling devices and improving the efficiency and functionality of multi-layer sampling devices. At the same time, it reduces material costs and well entry construction costs, and has significant scientific value and broad prospects for production application.

[0025] 2. In this invention, the one-way back pressure valves installed on the odd-numbered and even-numbered sampling layer pipelines have opposite conduction directions, so that nitrogen gas can be injected in different directions to extract formation fluids when sampling adjacent layers. The soluble ball seat can be installed every two sampling layers, reducing costs and avoiding the risk of formation fluid sampling distortion caused by excessive pressure grading of the one-way back pressure valves sampling in the same direction.

[0026] 3. The technical solution of this invention can realize multi-layer carbon dioxide sampling and monitoring. The method is easy to implement and simple to operate, providing technical support for the safe and efficient storage and monitoring of carbon dioxide. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of an embodiment of the underground fluid multilayer sampling device based on soluble spheres according to the present invention.

[0029] In the diagram: 11, First pipeline; 12, Second pipeline; 20, Sampling layer pipeline; 30, Nitrogen cylinder; 31, Nitrogen valve; 40, Sampling container; 41, Sampling valve; 50, One-way back pressure valve; 60, Fluid storage container; 70, Fluid filter; 71, One-way valve; 80, Interlayer packer; 90, Fluid isolation plate; 100, Soluble ball seat; 110, Formation fluid. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] In this invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0033] like Figure 1 As shown, in this embodiment, the monitoring well is divided into four fluid sampling layers by four interlayer packers 80. From the wellhead to the bottom of the well, the fluid sampling layers are the first, second, third and fourth layers, and each layer does not interfere with the others.

[0034] A multi-layer underground fluid sampling device based on soluble spheres includes a first pipeline 11 and a second pipeline 12 arranged along the depth direction of the monitoring well, and four sampling layer pipelines 20 arranged in each fluid sampling layer and connected to the first pipeline 11 and the second pipeline 12. Each sampling layer pipeline 20 is equipped with a one-way back pressure valve 50. The one-way back pressure valves 50 of the first and third layers have the same conduction direction, and the one-way back pressure valves 50 of the second and fourth layers have the same conduction direction. The conduction directions of the one-way back pressure valves 50 of the first and third layers are opposite to those of the one-way back pressure valves 50 of the second and fourth layers. Furthermore, the conduction pressure of the one-way back pressure valve 50 of the third layer is less than that of the one-way back pressure valve 50 of the first layer, and the conduction pressure of the one-way back pressure valve 50 of the fourth layer is less than that of the one-way back pressure valve 50 of the second layer. When sampling the first and third layers of fluid, the first pipeline 11 is connected to the nitrogen cylinder 30, and the second pipeline 12 is connected to the sampling container 40; when sampling the second and fourth layers of fluid, the first pipeline 11 is connected to the sampling container 40, and the second pipeline 12 is connected to the nitrogen cylinder 30. A soluble ball seat 100 is provided on the first pipeline 11 located between the second and third sampling layer pipelines 20. Isolation between the second and third fluid sampling layers is achieved by depositing appropriately sized soluble balls into the soluble ball seat 100.

[0035] In further optimization, in other embodiments, when more soluble ball seats 100 need to be set, the diameter of the soluble ball seats 100 should be ensured to decrease sequentially from the wellhead to the bottom of the well. This ensures that the soluble ball can pass smoothly through the upper layer of soluble ball seats 100 and fall accurately into the soluble ball seat 100 that is adapted to its size.

[0036] Further optimization involves installing a nitrogen valve 31 on the outlet pipeline of the nitrogen cylinder 30, which regulates the opening and closing of the nitrogen cylinder 30 and the nitrogen pressure.

[0037] To further optimize the process, a sampling valve 41 is installed on the inlet pipe of the sampling container 40, and the opening and closing of the sampling container 40 is adjusted by the sampling valve 41.

[0038] Further optimization involves installing a fluid filter 70 within each fluid sampling layer. The fluid filter 70 is connected to the sampling layer pipeline 20 via a fluid filtration pipeline, which is equipped with a one-way valve 71. Each sampling layer pipeline 20 is equipped with a fluid storage container 60. Formation fluid 110, after being filtered by the fluid filter 70, is stored in the fluid storage container 60 and then flows into the sampling container 40 under the displacement of nitrogen.

[0039] To further optimize the process and ensure that fluid leakage does not enter other layers and affect the quality of the extracted samples, each fluid sampling layer is divided into a formation fluid zone and a cavity zone by a formation fluid isolation plate 90. The fluid filter 70 is located in the formation fluid zone, and the sampling layer pipeline 20 is located in the cavity zone.

[0040] Further optimization involves using the soluble spheres, typically employed in fracturing operations in the oil and gas industry. These spheres are used in hydraulic fracturing processes, primarily to seal different working layers in the drilling string. After fracturing, these spheres dissolve, allowing oil and gas to flow out smoothly. This invention utilizes the soluble spheres in formation fluid sampling operations to seal different underground fluid sampling layers within the monitoring well, ensuring that underground fluids can be extracted from different layers. After sampling one layer of underground fluid, the soluble spheres dissolve, releasing the seal and becoming sampling channels for other formation fluid sampling layers. The soluble spheres are made of magnesium, aluminum, and other metal composite materials, dissolving through an electrochemical reaction after sampling, exhibiting high temperature and pressure resistance. The dissolution time of each layer of soluble spheres is selected or designed according to the fluid sampling time requirements.

[0041] Accordingly, the present invention also proposes a sampling method for the above-mentioned multi-layer underground fluid sampling device based on soluble spheres, comprising the following steps:

[0042] (1) Dispense soluble balls into the soluble ball seat located between the second and third sampling layers through the upper inlet of the first pipeline, thereby isolating the second and third fluid sampling layers. Calculate the time it takes for the soluble balls to fall into the soluble ball seat and wait for the soluble balls to fall into the soluble ball seat.

[0043] (2) Connect the first pipeline to the nitrogen cylinder and the second pipeline to the first sampling container.

[0044] (3) Open the nitrogen valve of the nitrogen cylinder to raise the pressure to the pressure of the first-level one-way back pressure valve.

[0045] (4) Open the sampling valve and use nitrogen to displace the first layer of formation fluid to the first sampling container. Since the conduction direction of the second layer one-way back pressure valve is opposite to that of the first layer, the second layer of formation fluid will not be displaced to the first sampling container.

[0046] (5) Connect the second pipeline to the nitrogen cylinder and the first pipeline to the second sampling container.

[0047] (6) Open the nitrogen valve of the nitrogen cylinder to raise the pressure to the pressure of the second-layer one-way back pressure valve.

[0048] (7) Open the sampling valve and use nitrogen to displace the second layer of formation fluid into the second sampling container.

[0049] (8) The soluble ball between the second sampling layer pipeline and the third sampling layer pipeline begins to dissolve until it is completely dissolved, thus connecting the second fluid sampling layer with the third fluid sampling layer.

[0050] (9) Connect the first pipeline to the nitrogen cylinder and the second pipeline to the third sampling container.

[0051] (10) Open the nitrogen valve of the nitrogen cylinder to raise the pressure to the pressure of the third-layer one-way back pressure valve.

[0052] (11) Open the sampling valve and use nitrogen to displace the third layer of formation fluid into the third sampling container. Since the conduction pressure of the third layer one-way back pressure valve is less than that of the first layer one-way back pressure valve, the first layer one-way back pressure valve will not open; while the direction of the second and fourth layer one-way back pressure valves is opposite to that of the third layer, so only the third layer of formation fluid will be displaced into the third sampling container.

[0053] (12) Connect the second pipeline to the nitrogen cylinder and the first pipeline to the fourth sampling container.

[0054] (13) Open the nitrogen valve of the nitrogen cylinder to raise the pressure to the pressure of the fourth-layer one-way back pressure valve.

[0055] (14) Open the sampling valve and use nitrogen to displace the fourth layer of formation fluid into the fourth sampling container. Since the conduction pressure of the fourth layer one-way back pressure valve is less than that of the second layer one-way back pressure valve, the second layer one-way back pressure valve will not open; while the directions of the first and third layer one-way back pressure valves are opposite to those of the fourth layer, so only the fourth layer of formation fluid will be displaced into the fourth sampling container.

[0056] It should be noted that in other embodiments, when there are five or six fluid sampling layers, before step (9), a soluble ball with a reduced diameter needs to be delivered to the soluble ball seat between the fourth and fifth sampling layers through the upper inlet of the first pipeline, thus isolating the fourth and fifth fluid sampling layers. Since the diameter of the soluble ball seat decreases sequentially from the wellhead to the bottom of the well, the soluble ball with a reduced diameter can pass smoothly through the soluble ball seat of the previous layer. Then, this process is repeated to complete the sampling of the formation fluids from the fifth to the sixth layer.

[0057] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0058] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0059] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A soluble sphere based multilayered sampling device for subsurface fluids, characterized in that, The sampling device comprises a first pipe and a second pipe arranged along the depth direction of a monitoring well, and n layer sampling layer pipes arranged in each layer of fluid sampling layer and connected with the first pipe and the second pipe, wherein n represents the total number of sampling layers; a one-way back pressure valve is arranged on each layer of sampling layer pipe; the conducting direction of the i-th layer one-way back pressure valve is opposite to that of the j-th layer one-way back pressure valve, i≤n and i is an odd number, j≤n and j is an even number, and the conducting pressure of the one-way back pressure valves on the same side decreases from the wellhead to the well bottom; when the fluid in the i-th layer is sampled, the first pipe is connected with a nitrogen cylinder and the second pipe is connected with a sampling container; when the fluid in the j-th layer is sampled, the first pipe is connected with the sampling container and the second pipe is connected with the nitrogen cylinder; a soluble ball seat is arranged on the first pipe or the second pipe between the j-th layer sampling layer pipe and the j+1-th layer sampling layer pipe, and the diameter of the soluble ball seat decreases from the wellhead to the well bottom; the isolation between adjacent fluid sampling layers is realized by delivering a soluble ball with a size suitable for the soluble ball seat into the soluble ball seat.

2. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, A nitrogen valve is arranged on the outlet pipe of the nitrogen cylinder, and the opening and closing of the nitrogen cylinder and the nitrogen pressure are adjusted through the nitrogen valve.

3. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, A sampling valve is arranged on the inlet pipe of the sampling container, and the opening and closing of the sampling container are adjusted through the sampling valve.

4. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, A fluid filter is arranged in each layer of fluid sampling layer, and the fluid filter is connected with the sampling layer pipe through a fluid filtering pipe.

5. The soluble sphere-based multilayered subsurface fluid sampling device of claim 4, wherein, A one-way valve is arranged on the fluid filtering pipe.

6. The soluble sphere-based multilayered subsurface fluid sampling device of claim 4, wherein, Each layer of fluid sampling layer is divided into a formation fluid area and a cavity area by a formation fluid isolation plate, the fluid filter is located in the formation fluid area, and the sampling layer pipe is located in the cavity area.

7. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, A fluid storage container is arranged on each layer of sampling layer pipe.

8. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, The soluble ball is made of a metal composite material, and is dissolved through an electrochemical reaction after sampling; the dissolution time of each layer of soluble ball is selected or designed according to the fluid sampling time requirement.

9. The soluble sphere-based multilayered subsurface fluid sampling device of claim 1, wherein, The total number of sampling layers n is in the range of 1≤n≤10.

10. A method for multilayer sampling of subsurface fluids based on dissolvable spheres, characterized in that, The sampling device comprises the sampling device according to any one of claims 1-9, and further comprises: S1, delivering a soluble ball to the soluble ball seat between the j-th layer sampling layer pipe and the j+1-th layer sampling layer pipe, so as to isolate the j-th layer fluid sampling layer from the j+1-th layer fluid sampling layer; j+1≤n; S2, sequentially sampling the j-1-th layer fluid sampling layer and the j-th layer fluid sampling layer: when sampling the j-1-th layer, connecting the first pipe with the nitrogen cylinder and the second pipe with the sampling container; when sampling the j-th layer, connecting the first pipe with the sampling container and the second pipe with the nitrogen cylinder; S3, after the j-th layer sampling is completed, the soluble ball between the j-th layer sampling layer pipe and the j+1-th layer sampling layer pipe starts to dissolve until completely dissolved, so as to connect the j-th layer fluid sampling layer with the j+1-th layer fluid sampling layer; S4, repeating S1-S3 to sample layer by layer from top to bottom; S5, when n is an odd number, finally sampling the n-th layer fluid sampling layer; when n is an even number, finally sequentially sampling the n-1-th layer fluid sampling layer and the n-th layer fluid sampling layer.

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