Supercritical carbon dioxide pressure monitoring device in shaft

Abstract

The invention relates to the technical field of carbon dioxide fracturing, and discloses a pressure monitoring device for supercritical carbon dioxide in a shaft, which comprises a shell, and a switch assembly is arranged on the shell; a monitoring mechanism is arranged on the upstream of the switch assembly in the shell and comprises a controller, a shell body, a monitoring spring and a telescopic assembly. All telescopic joints of the telescopic assembly are of hollow structures, one side of an inner cavity of the innermost telescopic joint communicates with an inner cavity of the shell, a piston plate is arranged on the other side of the inner cavity of the innermost telescopic joint, and carbon dioxide in the shell can enter the inner cavity of the innermost telescopic joint to drive the innermost telescopic joint to extend so as to compress the monitoring spring; a plurality of laser emitters are arranged on one side of the monitoring spring in the shell at intervals, laser receivers are arranged at the positions, corresponding to the laser emitters, of the other side of the monitoring spring, and the controller is electrically connected with the laser emitters and the laser receivers. The monitoring device can effectively isolate erosion and corrosion of drilling fluid, delay aging failure of electronic elements and prolong the service life of equipment.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide fracturing technology, and in particular to a supercritical carbon dioxide pressure monitoring device for wellbore. Background Technology

[0002] Supercritical carbon dioxide fracturing technology, as a highly efficient and environmentally friendly oil and gas extraction and production enhancement technology, has broad application prospects in oil and gas field development. However, current supercritical carbon dioxide fracturing phase monitoring equipment is generally limited by both extreme downhole conditions and existing monitoring methods, making it difficult to meet actual operational needs.

[0003] The core monitoring modes of existing monitoring equipment have significant shortcomings. Most devices rely on direct contact between sensor probes and carbon dioxide fluid to monitor parameters such as pressure and phase. However, the downhole environment is extremely complex and harsh. During fracturing operations, there is intense fluid impact, and the high-speed flow of solid particles produced by the formation causes continuous wear on the sensor probes, easily leading to probe damage, decreased sensitivity, and consequently, data distortion and equipment malfunctions. Furthermore, as drilling depth increases, downhole temperature and pressure fluctuate dramatically, and these large variations further affect the stability of sensor monitoring. In addition, monitoring equipment immersed in drilling fluid for extended periods suffers from corrosion and erosion of internal electronic components, leading to aging and malfunction, shortening equipment lifespan, increasing maintenance costs, and failing to provide continuous and reliable monitoring data for fracturing operations, thus failing to meet the actual needs of field operations. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a supercritical carbon dioxide pressure monitoring device for wellbore.

[0005] This invention provides a supercritical carbon dioxide pressure monitoring device for wellbore, comprising a tubular outer shell connected to the wellbore, and a switch assembly on the outer shell capable of controlling the on / off state of the upstream and downstream sides of the outer shell; a monitoring mechanism is located upstream of the switch assembly in the outer shell, the monitoring mechanism including a controller, a housing within the outer shell, and a monitoring spring and a telescopic assembly both located within the housing; all telescopic joints of the telescopic assembly are hollow structures, with one side of the innermost telescopic joint communicating with the inner cavity of the outer shell, and the other side having a piston plate, allowing carbon dioxide from the outer shell to enter the inner cavity of the innermost telescopic joint, driving the innermost telescopic joint to extend and compress the monitoring spring; on both sides of the monitoring spring in the housing, one side is spaced apart with multiple laser emitters capable of emitting lasers, and the other side has laser receivers corresponding to the positions of the laser emitters, and the controller is electrically connected to the laser emitters and laser receivers; when the telescopic assembly extends, the telescopic joints of the telescopic assembly can block the laser emitted by the corresponding laser emitter to the laser receiver, and the controller determines the extension length of the telescopic assembly based on the number of blocked lasers and the spacing between adjacent lasers, and determines the carbon dioxide pressure according to the correspondence between the extension length and the carbon dioxide pressure.

[0006] Optionally, the switch assembly includes a ball table disposed inside the housing and enclosing one end of the housing. A groove is formed on the upstream surface of the ball table, and a connecting channel penetrating the ball table is formed at the bottom of the groove. A soluble ball capable of dissolving in supercritical carbon dioxide is disposed inside the groove. When carbon dioxide enters the housing, it can act on the soluble ball, causing the soluble ball to block the inlet of the connecting channel. When the carbon dioxide in the housing reaches a supercritical state, the soluble ball dissolves, and the inlet of the connecting channel is unblocked.

[0007] Optionally, a limiting component is provided on the upstream side of the table's groove. The limiting component includes a first cavity, a vertical hydraulic cavity, and an inclined hydraulic cavity, all of which are opened on the table. One end of the first cavity is connected to the groove, and the other end is connected to a hydraulic spring. A limiting member is connected to the hydraulic spring, which can extend out of the first cavity to abut against the ball and limit the ball. The outer wall of the limiting member is dynamically sealed to the inner wall of the first cavity. One end of the vertical hydraulic cavity and the inclined hydraulic cavity are both connected to the side of the first cavity where the hydraulic spring is located, and the other end of the vertical hydraulic cavity and the inclined hydraulic cavity are both connected to the inner cavity of the outer shell.

[0008] Optionally, the controller is electrically connected to multiple indicator lights, each located on the ground. Each pair of laser transmitters and laser receivers is equipped with a corresponding indicator light. When the laser receiver can receive the laser emitted by the laser transmitter, the controller continuously activates the corresponding indicator light. When the laser receiver cannot receive the laser emitted by the laser transmitter, the controller controls the corresponding indicator light to turn off.

[0009] Optionally, the telescopic assembly has a brittle plate on the side away from the monitoring spring that can seal the inner cavity of the telescopic assembly. The brittle plate can be broken under the action of carbon dioxide at a corresponding pressure.

[0010] Optionally, each expansion joint of the expansion assembly is coaxially sleeved along the axial direction of the expansion assembly, and adjacent expansion joints are slidable and dynamically sealed.

[0011] Optionally, a spring plate is provided at one end of the monitoring spring near the telescopic assembly, and a damping damper is provided on the spring plate. The telescopic end of the telescopic assembly can act on the damping damper, and the damping damper compresses the monitoring spring through the spring plate.

[0012] Optionally, the damping shock absorber includes a cylinder, a first support, a second support, and a telescopic rod and a damping spring, both of which are disposed within the cylinder. The first and second supports each have an annular groove at their adjacent ends. Both ends of the cylinder are slidably confined within the corresponding grooves, and both ends of the cylinder can slide along the cylinder's own axial direction within the corresponding grooves. One end of the second support is connected to a spring plate, and the other end is connected to the telescopic rod. The telescopic end of the telescopic rod is connected to the first support. The damping spring is sleeved on the telescopic rod, and both ends are connected to the first and second supports respectively.

[0013] Optionally, a rigid sliding sleeve is connected to the end of the first support away from the cylinder body, and a cover plate is provided at the end of the rigid sliding sleeve away from the first support. The telescopic end of the telescopic rod passes through the first support and the rigid sliding sleeve and is connected to the cover plate.

[0014] Optionally, the damping spring is a mating disc spring.

[0015] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art: 1. By setting up a housing, the telescopic component, laser transmitter, and laser receiver are all housed within the housing, which can effectively isolate the drilling fluid from erosion and corrosion, delay the aging and failure of electronic components, extend the service life of the equipment, reduce operation and maintenance costs, and prevent the laser transmitter and laser receiver from being damaged by downhole fluids and solid particles due to wear. Therefore, the monitoring device of the present invention not only solves the wear problem caused by direct contact with supercritical carbon dioxide fracturing fluid in existing equipment, but also solves the problem that the sensors of existing equipment will be corroded by drilling fluid during the drilling process.

[0016] 2. The monitoring device of the present invention uses carbon dioxide to drive the telescopic component. When the telescopic component extends, it can block the laser. The extension length of the telescopic component is calculated by combining the number of laser blocks with the spacing, and then the pressure is determined accordingly. Therefore, the monitoring process does not rely on easily damaged contact probes and can meet the actual operational needs of supercritical carbon dioxide fracturing pressure monitoring under extreme downhole conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a supercritical carbon dioxide pressure monitoring device in a wellbore provided in Embodiment 1 of the present invention.

[0018] Figure 2 This is a schematic diagram of the limiting component provided in Embodiment 1 of the present invention.

[0019] Figure 3 This is a schematic diagram of the monitoring mechanism provided in Embodiment 1 of the present invention.

[0020] Figure 4 This is a schematic diagram of the damping vibration damper provided in Embodiment 1 of the present invention.

[0021] Figure 5 This is a schematic diagram of the structure of a laser emitter and a laser receiver disposed inside the outer casing in Embodiment 1 of the present invention.

[0022] Explanation of reference numerals in the attached drawings: 1. Ball table; 1-1. Hydraulic spring; 1-2. Limiting component; 1-3. Vertical hydraulic chamber; 1-4. Inclined hydraulic chamber; 2. Melting ball; 3. Housing; 4. Monitoring spring; 5. Spring plate; 6. Damping damper; 6-1. Telescopic rod; 6-2. Cylinder; 6-3. Damping spring; 6-4. First support; 6-5. Second support; 6-6. Rigid sliding sleeve; 6-7. Viscoelastic cover plate; 7. Piston plate; 8. Brittle plate; 9. Telescopic assembly; 10. Inner cavity; 11. Laser emitter; 12. Laser receiver. Detailed Implementation

[0023] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention 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 invention.

[0025] Example 1: like Figure 1 , Figure 3 and Figure 5As shown, a supercritical carbon dioxide pressure monitoring device for a wellbore includes a tubular outer shell connected to the wellbore. A switching assembly capable of controlling the on / off state of the upstream and downstream sides of the shell is provided on the outer shell. A monitoring mechanism is located upstream of the switching assembly within the shell. The monitoring mechanism includes a controller, a housing 3 within the outer shell, and monitoring springs 4 and telescopic components 9, all housed within the housing 3. All telescopic joints of the telescopic component 9 are hollow structures. One side of the innermost telescopic joint's cavity communicates with the inner cavity of the outer shell, while the other side is equipped with a piston plate 7. Carbon dioxide from the outer shell can enter the inner cavity of the innermost telescopic joint, driving it to extend and compress the monitoring springs 4. The monitoring spring 4 is located on both sides of the housing. On one side, multiple laser emitters 11 capable of emitting lasers are arranged at intervals. On the other side, laser receivers 12 capable of receiving lasers are arranged at the positions corresponding to the laser emitters 11. The controller is electrically connected to the laser emitters 11 and the laser receivers 12. When the telescopic component 9 extends, the telescopic joint of the telescopic component 9 can block the laser emitted by the corresponding laser emitter 11 to the laser receiver 12. The controller determines the extension length of the telescopic component 9 based on the number of lasers blocked and the distance between adjacent lasers, and determines the carbon dioxide pressure according to the correspondence between the extension length and the carbon dioxide pressure.

[0026] In this embodiment, the piston plate 7 closes one end of the innermost telescopic joint; the housing is tubular, and the center line of the housing is perpendicular to the center line of the outer shell; the positions where the laser emitter 11 and the laser receiver 12 are located are provided with inner cavities 10, and the laser emitter 11 or the laser receiver 12 is located in the corresponding inner cavity 10.

[0027] like Figure 1 As shown, the switch assembly includes a ball platform 1 disposed inside the housing and enclosing one end of the housing. A groove is formed on the upstream surface of the ball platform 1, and a connecting channel is formed at the bottom of the groove, penetrating the ball platform 1. A dissolving ball 2 capable of dissolving in supercritical carbon dioxide is disposed inside the groove. When carbon dioxide enters the housing, it can act on the dissolving ball 2, causing the dissolving ball 2 to block the inlet of the connecting channel. When the carbon dioxide in the housing reaches a supercritical state, the dissolving ball 2 dissolves, and the inlet of the connecting channel is unblocked.

[0028] In this embodiment, the soluble ball 2 is made of naphthalene.

[0029] like Figure 2As shown, a limiting component is provided on the upstream side of the groove of the ball table 1. The limiting component includes a first cavity, a vertical hydraulic cavity 1-3, and an inclined hydraulic cavity 1-4, all of which are opened in the ball table 1. One end of the first cavity is connected to the groove, and the other end is connected to a hydraulic spring 1-1. A limiting member 1-2 is connected to the hydraulic spring 1-1, which can extend out of the first cavity and abut against the ball 2 and limit the ball 2. The outer wall of the limiting member 1-2 is dynamically sealed to the inner wall of the first cavity. One end of the vertical hydraulic cavity 1-3 and the inclined hydraulic cavity 1-4 are both connected to the side of the first cavity where the hydraulic spring 1-1 is located, and the other end of the vertical hydraulic cavity 1-3 and the inclined hydraulic cavity 1-4 are both connected to the inner cavity of the outer shell.

[0030] In this embodiment, after carbon dioxide enters the first cavity through the vertical hydraulic cavity 1-3 and the inclined hydraulic cavity 1-4, the limiting member 1-2 is pushed to extend out of the first cavity; the hydraulic spring has a reset function; the limiting components are multiple components evenly arranged around the center line of the outer shell, and the height of the end of the limiting member 1-2 that abuts against the melting ball 2 after extending out of the first cavity is higher than the height of the center of the melting ball 2.

[0031] The controller is electrically connected to multiple indicator lights, all of which are located on the ground. Each pair of laser transmitters 11 and laser receivers 12 is equipped with a corresponding indicator light. When the laser receiver 12 can receive the laser emitted by the laser transmitter 11, the controller continuously activates the corresponding indicator light. When the laser receiver 12 cannot receive the laser emitted by the laser transmitter 11, the controller controls the corresponding indicator light to turn off.

[0032] The telescopic component 9 is provided with a brittle plate 8 on the side away from the monitoring spring 4, which can seal the inner cavity of the telescopic component 9. The brittle plate 8 can be broken under the action of carbon dioxide under corresponding pressure.

[0033] The expansion joints of the expansion assembly 9 are coaxially sleeved together in sequence along the axial direction of the expansion assembly, and adjacent expansion joints are slidable and dynamically sealed.

[0034] In this embodiment, the telescopic assembly is an external telescopic assembly. The telescopic joint of the telescopic assembly has a larger diameter on one side and a smaller diameter on the other side. Between two adjacent telescopic joints, the end with the smaller diameter of one telescopic joint and the end with the larger diameter of the other telescopic joint are slidably connected in a dynamic seal. The two telescopic joints are respectively connected to a first limiting part and a second limiting part, which prevents the telescopic joints from separating.

[0035] A spring plate 5 is provided at one end of the monitoring spring 4 near the telescopic assembly 9. A damping damper 6 is provided on the spring plate 5. The telescopic end of the telescopic assembly 9 can act on the damping damper 6. The damping damper 6 compresses the monitoring spring 4 through the spring plate 5.

[0036] like Figure 4As shown, the damping shock absorber 6 includes a cylinder 6-2, a first support 6-4, a second support 6-5, and a telescopic rod 6-1 and a damping spring 6-3, both of which are disposed within the cylinder 6-2. The first support 6-4 and the second support 6-5 each have an annular groove at their respective ends. Both ends of the cylinder 6-2 are slidably confined within the corresponding grooves, and both ends of the cylinder 6-2 can slide along the cylinder's own axis within the corresponding grooves. One end of the second support 6-5 is connected to the spring plate 5, and the other end is connected to the telescopic rod 6-1. The telescopic end of the telescopic rod 6-1 is connected to the first support 6-4. The damping spring 6-3 is sleeved on the telescopic rod 6-1, and both ends are connected to the first support 6-4 and the second support 6-5, respectively.

[0037] The end of the first support 6-4 away from the cylinder 6-2 is connected to a rigid sliding sleeve 6-6. The end of the rigid sliding sleeve 6-6 away from the first support 6-4 is provided with a cover plate 6-7. The telescopic end of the telescopic rod 6-1 passes through the first support 6-4 and the rigid sliding sleeve 6-6 and is connected to the cover plate 6-7.

[0038] In this embodiment, the cover plate 6-7 is made of an elastic material with self-adhesion, such as silicone pressure-sensitive adhesive.

[0039] The damping spring 6-3 is a mating disc spring.

[0040] Working principle: In use, the outer casing is installed on the wellbore. Initially, the switch assembly is closed. Carbon dioxide is continuously introduced into the outer casing until it reaches a supercritical state, at which point the switch assembly is opened. During this process, carbon dioxide can enter the inner cavity of the telescopic assembly, causing it to extend. The extension length of the telescopic assembly can be determined by the number of lasers blocked by the telescopic assembly and the spacing between adjacent lasers. Then, the carbon dioxide pressure is determined based on the relationship between the extension length and the carbon dioxide pressure.

[0041] The relationship between the elongation length and the carbon dioxide pressure can be obtained in advance through experiments. For example, by turning off the switch assembly and introducing carbon dioxide at a known pressure into the housing, the elongation length of the telescopic assembly can be obtained. Then, by conducting multiple sets of experiments, the relationship between different elongation lengths and carbon dioxide pressure can be obtained.

[0042] The above inventions are merely a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A supercritical carbon dioxide pressure monitoring device for wellbore, characterized in that, It includes a tubular outer shell connected to the wellbore, and a switch assembly on the outer shell that can control the on / off state of the upstream and downstream sides of the outer shell. The switch assembly opens when the carbon dioxide in the upstream side of the outer shell reaches a supercritical state and closes when it does not. An upstream monitoring mechanism is located within the casing of the switching assembly. This mechanism includes a controller, a housing within the casing, and monitoring springs and telescopic components all housed within the housing. All telescopic joints of the telescopic component are hollow structures. One side of the innermost telescopic joint's cavity is connected to the inner cavity of the casing, while the other side is sealed by a piston plate. Carbon dioxide from within the casing can enter the inner cavity of the innermost telescopic joint, driving it to extend and compress the monitoring spring. On both sides of the monitoring spring within the casing, multiple laser emitters capable of emitting lasers are spaced apart on one side, and laser receivers capable of receiving lasers are located at corresponding positions on the other side. The controller is electrically connected to the laser emitters and receivers. When the telescopic component extends, its telescopic joints can block the lasers emitted by the corresponding laser emitters from the laser receivers. The controller determines the extension length of the telescopic component based on the number of blocked lasers and the spacing between adjacent lasers, and determines the carbon dioxide pressure based on the correlation between the extension length and the carbon dioxide pressure.

2. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 1, characterized in that, The switching assembly includes a ball table disposed inside the housing and enclosing one end of the housing. A groove is formed on the upstream surface of the ball table, and a connecting channel is formed at the bottom of the groove, penetrating the ball table. A soluble ball capable of dissolving in supercritical carbon dioxide is disposed inside the groove. When carbon dioxide enters the housing, it can act on the soluble ball, causing the soluble ball to block the inlet of the connecting channel. When the carbon dioxide in the housing reaches a supercritical state, the soluble ball dissolves, and the inlet of the connecting channel is unblocked.

3. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 2, characterized in that, A limiting component is provided on the upstream side of the tabletop groove. The limiting component includes a first cavity, a vertical hydraulic cavity, and an inclined hydraulic cavity, all of which are opened in the tabletop. One end of the first cavity is connected to the groove, and the other end is connected to a hydraulic spring. A limiting member is connected to the hydraulic spring, which can extend out of the first cavity to abut against the ball and limit the ball. The outer wall of the limiting member is dynamically sealed to the inner wall of the first cavity. One end of the vertical hydraulic cavity and the inclined hydraulic cavity are both connected to the side of the first cavity where the hydraulic spring is located, and the other end of the vertical hydraulic cavity and the inclined hydraulic cavity are both connected to the inner cavity of the outer shell.

4. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 1, characterized in that, The controller is electrically connected to multiple indicator lights, all located on the ground. Each pair of laser emitters and laser receivers is equipped with a corresponding indicator light. When the laser receiver can receive the laser emitted by the laser emitter, the controller continuously activates the corresponding indicator light. When the laser receiver cannot receive the laser emitted by the laser emitter, the controller controls the corresponding indicator light to turn off.

5. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 1, characterized in that, The telescopic assembly has a brittle plate on the side away from the monitoring spring that can seal the inner cavity of the telescopic assembly. The brittle plate can be broken under the action of carbon dioxide at a corresponding pressure.

6. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 1, characterized in that, The expansion joints of the expansion assembly are coaxially sleeved together along the axial direction of the expansion assembly, and adjacent expansion joints are slidable and dynamically sealed.

7. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 1, characterized in that, The monitoring spring has a spring plate at one end near the telescopic assembly, and a damping damper is provided on the spring plate. The telescopic end of the telescopic assembly can act on the damping damper, and the damping damper compresses the monitoring spring through the spring plate.

8. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 7, characterized in that, The damping shock absorber includes a cylinder, a first support, a second support, and a telescopic rod and a damping spring, all of which are installed inside the cylinder. Both the first and second supports have annular grooves at their close ends. Both ends of the cylinder can slide within the corresponding grooves, and both ends of the cylinder can slide along the cylinder's own axis within the corresponding grooves. One end of the second support is connected to the spring plate, and the other end is connected to the telescopic rod. The telescopic end of the telescopic rod is connected to the first support. The damping spring is sleeved on the telescopic rod, and its two ends are connected to the first support and the second support respectively.

9. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 8, characterized in that, The first support is connected to a rigid sliding sleeve at the end away from the cylinder body. The rigid sliding sleeve is provided with a cover plate at the end away from the first support. The telescopic end of the telescopic rod passes through the first support and the rigid sliding sleeve and is connected to the cover plate.

10. The supercritical carbon dioxide pressure monitoring device in a wellbore as described in claim 8, characterized in that, The damping spring is a mating disc spring.

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