Intelligent sleeve isolation floating valve and control system thereof

Abstract

The invention relates to the technical field of petroleum drilling, in particular to an intelligent casing isolation floating valve and a control system thereof, and the system comprises a casing control unit which is used for installing a floating valve on a casing, controlling the installed casing to enter a drilling well and recording the entering depth; the pressure detection unit is used for detecting the pressure of the drilling fluid in the casing pipe; the flow detection unit is used for detecting the reverse output of the drilling fluid; a float valve monitoring unit to determine a state of the float valve; the adjusting unit is used for adjusting the shear pin thickness of the floating valve entering the drilling well next time or reducing the drilling fluid pressure, adjusting the drilling fluid entering amount according to the state of the floating valve and adjusting the impact distance based on the area of the critical blind plate; according to the intelligent casing pipe isolation floating valve control system, all the units cooperate with one another, the casing pipe lowering difficulty and risk are effectively reduced, and meanwhile the stability and accuracy of the intelligent casing pipe isolation floating valve control system are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, and in particular to an intelligent casing isolation floating valve and a control system thereof. Background Art

[0002] In oil drilling operations, the casing lowering process is crucial. Existing casing isolation devices have many shortcomings, such as unstable sealing performance, which easily leads to mud leakage and affects the lowering of the casing; limited floating function, which is difficult to adapt to complex well conditions and different mud density environments; and problems in opening reliability, which are prone to misoperation or failure to open normally or mis-opening, seriously affecting the efficiency and safety of drilling operations. Therefore, it is of great significance to develop a casing isolation floating valve with reliable performance and adaptability to complex working conditions.

[0003] Chinese patent application publication number: CN108301788A discloses a floating coupling device, which is a floating coupling device, including a coupling body; the coupling body is a cylindrical shape with an installation cavity that is transparent from top to bottom, and a pressure differential sleeve is fixedly installed on the upper part of the installation cavity of the coupling body through a pin hole and a shear pin, and the pressure differential sleeve is a cylindrical shape with a larger upper part and a smaller lower part. By forming a temporary barrier in the casing, the casing column below the sliding circular plate is filled with air, and the casing column above the sliding circular plate is filled with drilling fluid, which increases the buoyancy of the casing column below the sliding circular plate, so that the lower casing string is in a floating state during the casing lowering process. After the casing string reaches the predetermined position, the sliding sleeve and the sliding circular plate cut off the shear pin and move downward, so that the drilling fluid of the upper casing enters the lower casing, making it easy to lower the casing string, effectively reducing the resistance of the casing lowering, and improving the working efficiency of the casing lowering and the cementing quality.

[0004] Chinese patent application publication number: CN118462075A discloses a sealing nipple for floating casing, which includes a nipple barrel and a sealing assembly. The two ends of the nipple barrel are configured to be connected to a first casing and a second casing respectively, and a protrusion is provided on the inner wall of the nipple barrel. The sealing assembly is arranged in the nipple barrel, and the sealing assembly includes a soluble plug, one end of the soluble plug abuts against the protrusion, and the soluble plug divides the inner cavity of the nipple barrel into two independent chambers. The first casing is located on the side of the soluble plug away from the protrusion, and the first casing is filled with a dissolving liquid, and the dissolving liquid can dissolve the soluble plug within a set time. When lowering the casing, the first casing is filled with dissolving liquid and drilling fluid, and the second casing is filled with air. The second casing is lowered into the well first. During the lowering process, the dissolving liquid will gradually dissolve the soluble plug until the casing is lowered to the bottom of the well, and the soluble plug is completely dissolved. The drilling fluid penetrates the first casing and the second casing. There is no need for manual operation of the sealing assembly, which is simple, fast, time-saving and labor-saving.

[0005] However, the above method has the following problems: During the process of casing running, it is impossible to effectively set the subsequent floating valves according to different states of the floating valve, and it is impossible to direct the drainage of the broken blind plate according to different drilling depths. Summary of the Invention

[0006] Therefore, the present invention provides an intelligent casing isolation floating valve and its control system to overcome the problems in the prior art that during the process of casing running, it is impossible to effectively set the subsequent floating valves according to different states of the floating valve, and it is impossible to direct the drainage of the broken blind plate according to different drilling depths.

[0007] To achieve the above object, on the one hand, the present invention provides an intelligent casing isolation floating valve control system, including: A casing control unit, which is used to install a floating valve on the casing, control the installed casing to enter the well and record the entering depth; A pressure detection unit, which is connected to the casing control unit and used to detect the drilling fluid pressure in the casing; A flow detection unit, which is connected to the casing control unit and used to detect the drilling fluid return volume; A floating valve monitoring unit, which is respectively connected to the pressure detection unit and the flow detection unit and used to determine the state of the floating valve by combining the drilling fluid pressure and the drilling fluid return volume. The states of the floating valve include floating valve open, floating valve closed and floating valve partially open; An adjustment unit, which is respectively connected to the casing control unit and the floating valve monitoring unit and used to adjust the shear pin thickness of the floating valve entering the well next time or reduce the drilling fluid pressure by combining the entering depth and the state of the floating valve, adjust the drilling fluid inflow according to the state of the floating valve, and adjust the impact distance based on the area of the critical blind plate. The critical blind plate is arranged on the floating valve blind plate.

[0008] Further, it further includes: A first-stage control unit, which is respectively connected to the casing control unit and the floating valve monitoring unit and used to, when the floating valve is in the open state, guide the broken blind plate to perform corresponding actions and straighten the casing according to the electromagnetic coil in the first drilling section of the casing. The floating valve blind plate is made of ferromagnetic material. The drilling section includes the first drilling section and the second drilling section, and the first drilling section is located above the second drilling section; The second-stage control unit is respectively connected to the casing control unit and the floating valve monitoring unit, and is used to vibrate the breaking blind plate and straighten the casing through the acoustic centralizer when the casing is in the second drilling section and the floating valve is in the open state. The breaking blind plate is generated by the floating valve blind plate breaking after being impacted.

[0009] Further, the adjustment unit includes: The shear pin setting sub-unit includes a shear pin and is respectively connected to the casing control unit and the floating valve monitoring unit. It is used to determine whether the casing reaches the working position according to the penetration depth, and adjust the shear pin thickness of the floating valve for the next drilling or reduce the drilling fluid pressure according to the state of the floating valve when it is determined that the casing reaches the working position. Among them, If the floating valve is in a partially open state, it is determined to reduce the drilling fluid pressure. If the floating valve is in an open state, it is determined to increase the shear pin thickness of the floating valve for the next drilling.

[0010] Further, the adjustment unit further includes: The drilling fluid adjustment sub-unit includes the floating valve blind plate and is respectively connected to the casing control unit and the floating valve monitoring unit. It is used to adjust the drilling fluid inflow according to the state of the floating valve when the floating valve is in a partially open state or a closed state. Among them, If the floating valve is in a partially open state, it is determined to reduce the drilling fluid inflow.

[0011] Further, the adjustment unit further includes: The impact distance setting sub-unit includes a striker seat and a pressure-bearing seat and is respectively connected to the casing control unit and the floating valve monitoring unit. It is used to establish a relationship model between the area ratio and the impact distance by combining the area ratio of the critical blind plate to the floating valve blind plate and the impact distance, and determine the impact distance corresponding to different area ratios according to the relationship model.

[0012] Further, when the drilling fluid pressure drops, the floating valve monitoring unit compares the drilling fluid backflow volume with a first preset backflow volume and a second preset backflow volume, and determines the state of the floating valve according to the comparison result. The first preset backflow volume is positively correlated with the critical blind plate area, the second preset backflow volume is positively correlated with the floating valve blind plate area, and the first preset backflow volume is less than the second preset backflow volume.

[0013] Further, when the casing is in the first drilling section and the floating valve is open, the first-stage control unit generates a magnetic field through an electromagnetic coil to guide the breaking blind plate to leave the casing along with the drilling fluid, and when the casing is in the second drilling section and the floating valve is open, it guides the breaking blind plate to return to the ground along with the drilling fluid.

[0014] Further, when the casing is in the second drilling section and the floating valve is open, the second-stage control unit generates a radiation force through an acoustic centralizer to vibrate the breaking blind plate to leave the casing along with the drilling fluid.

[0015] On the other hand, the present invention provides a casing isolation floating valve based on an intelligent casing isolation floating valve control system, comprising: A floating valve blind plate provided with a critical blind plate for preventing drilling fluid from overflowing from the casing during the process of the casing entering the well. A firing pin seat with sharp teeth provided at its upper end for breaking the floating valve blind plate by impacting with the floating valve blind plate. A pressure-bearing seat for supporting the floating valve blind plate when the floating valve is in the closed state or partially open state. A shear pin for fixing the firing pin seat and the pressure-bearing seat when the floating valve is in the closed state or the partially open state.

[0016] Further, the pressure-bearing capacity of the critical blind plate is less than that of the floating valve blind plate, and the pressure-bearing capacity is the maximum pressure that the blind plate can withstand while remaining intact.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a casing isolation floating valve provided on the casing. Through the structural design of the casing isolation floating valve, it effectively prevents mud leakage, ensures the stability of the casing lowering process. At the same time, the structure of the casing isolation floating valve can maintain a good floating state under different mud densities, reducing the difficulty and risk of casing lowering. Through the design that the shear pin breaks and the floating valve blind plate is broken by the sharp teeth at the upper end of the firing pin seat, the opening action of the valve is accurate and reliable, avoiding misoperation. While reducing operation time and cost and improving operation efficiency, it effectively improves the stability and accuracy of the intelligent casing isolation floating valve control system.

[0018] Furthermore, the present invention sets different centralizers for different drilling sections at different depths. While centralizing the casing, it guides the broken blind plate to flow back to the ground along with the drilling fluid. By setting a centralizer to guide the broken blind plate to flow back to the ground, it can effectively avoid the direct impact of these fragments on downhole equipment, extend the service life of the equipment, reduce the equipment maintenance and replacement costs, reduce the non-production time caused by equipment failures, improve the drilling operation efficiency, timely guide the broken blind plate to the ground, maintain the smoothness of the drilling fluid circulation system, maintain the stability of the downhole pressure, ensure the safe progress of the drilling operation, and reduce the potential hazards caused by safety accidents to personnel and the environment. During the cementing process, the centralizing effect of the casing is crucial for the cementing quality. The centralizer can keep the casing centered in the wellbore, ensure that the cement slurry can be evenly distributed around the casing, form a good cement sheath, improve the sealing performance between the casing and the formation. At the same time, removing the broken blind plate avoids its interference with the cementing operation, helps to ensure the normal flow and setting of the cement slurry, thereby improving the cementing quality, enhancing the stability and sealing performance of the casing, preventing the mutual flow of formation fluids and fluids inside the casing. At the same time, by timely removing the broken blind plate, it can reduce the risks of these subsequent operations, ensure the smooth progress of various operations, and further improve the stability and accuracy of the intelligent casing isolation floating valve control system.

[0019] Furthermore, the present invention adjusts the relevant components of the floating valve connected to the next drilled casing by utilizing different states of the floating valve during the drilling process of the casing. During the drilling process, different states of the floating valve (such as open, closed, partially open, etc.) reflect downhole working condition information such as pressure and flow rate. By adjusting the components of the floating valve connected to the next drilled casing according to these states, the floating valve can better adapt to the actual downhole situation, optimize the circulation path and flow rate of the drilling fluid, ensure that the drilling fluid can effectively carry cuttings back to the ground, improve the drilling efficiency, and at the same time reduce downhole problems caused by poor drilling fluid circulation. Reasonably adjusting the components of the floating valve can reduce failures and downtime during the drilling process. When the floating valve can work stably and normally, the drilling operation can be carried out more continuously without frequent handling and adjustment due to floating valve problems. Different formations have different pressures, temperatures and geological characteristics, which will affect the working state of the floating valve. By adjusting the components of the next floating valve according to the state feedback of the floating valve during the drilling process, it can better adapt to different formation conditions, and further improve the stability and accuracy of the intelligent casing isolation floating valve control system.

[0020] Furthermore, the present invention uses a critical blind plate to be set on the floating valve blind plate, and determines the state of the casing during drilling by detecting the drilling-related parameters of the blind plates with different pressure bearing capacities after they are broken. The blind plates with different pressure bearing capacities will break when subjected to different pressures. By monitoring the breaking of the blind plates, the real-time pressure condition in the casing can be intuitively understood. When a blind plate with a certain pressure bearing capacity breaks, it indicates that the downhole pressure has reached or exceeded the pressure bearing limit of the blind plate. After the blind plate is broken, the flow state of the drilling fluid will change, and related parameters such as the drilling fluid backflow amount and flow rate will also change accordingly. By detecting these parameters The data can evaluate the flow of drilling fluid in the casing. The crushing of the blind plate is closely related to the state of the casing during the lowering process. During the casing lowering process, if resistance or other abnormal conditions are encountered, it may cause pressure fluctuations in the casing, thereby affecting the crushing of the blind plate. By analyzing the drilling-related parameters after the blind plate is crushed, it is possible to understand whether the current drilling operation parameters (such as drilling speed, drilling fluid density, etc.) are reasonable. If the blind plate crushing is found to be abnormal, it may be necessary to adjust the drilling parameters to adapt to the actual situation downhole, further improving the stability and accuracy of the intelligent casing isolation floating valve control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the intelligent casing isolation floating valve control system of the present invention; Figure 2 It is a structural diagram of a drilling section according to an embodiment of the present invention; Figure 3 This is a structural diagram of a casing isolation floating valve according to an embodiment of the present invention; Figure 4 This is a structural diagram of a floating valve blind plate according to an embodiment of the present invention; Among them, 1, upper joint; 2, upper rubber pad; 3, floating valve blind plate; 4, lower rubber pad; 5, striker seat; 51, sharp teeth; 6, pressure seat; 7, shear pin; 8, lower joint; 9, first sealing ring; 10, second sealing ring; 11, third sealing ring; 12, casing isolation floating valve; 13, electromagnetic coil; 14, sonic straightener; 15, casing; 16, first drilling section; 17, second drilling section; 18, critical blind plate. DETAILED DESCRIPTION

[0022] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0024] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0025] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Please refer to Figure 1 as shown, which is a structural diagram of the intelligent casing isolation floating valve control system of the present invention. An intelligent casing isolation floating valve control system includes: A casing control unit, which is used to install a floating valve on the casing, and control the installed casing to enter the wellbore and record the entry depth. A pressure detection unit, which is connected to the casing control unit and used to detect the drilling fluid pressure in the casing. A flow rate detection unit, which is connected to the casing control unit and used to detect the drilling fluid return volume. A floating valve monitoring unit, which is respectively connected to the pressure detection unit and the flow rate detection unit, and is used to determine the state of the floating valve by combining the drilling fluid pressure and the drilling fluid return volume. The states of the floating valve include floating valve open, floating valve closed, and floating valve partially open. An adjustment unit, which is respectively connected to the casing control unit and the floating valve monitoring unit, and is used to adjust the shear pin thickness of the floating valve for the next entry into the wellbore or reduce the drilling fluid pressure by combining the entry depth and the state of the floating valve, adjust the drilling fluid entry volume according to the state of the floating valve, and adjust the impact distance based on the area of the critical blind plate. The critical blind plate is set on the floating valve blind plate.

[0027] Specifically, the present invention utilizes a casing isolation floating valve provided on the casing. Through the structural design of the casing isolation floating valve, mud leakage is effectively prevented, ensuring the stability of the casing running process. At the same time, the structure of the casing isolation floating valve can maintain a good floating state under different mud densities, reducing the difficulty and risk of casing lowering. Through the design that the shear pin breaks and the floating valve blind plate is broken by the sharp teeth at the upper end of the striker seat, the opening action of the valve is accurate and reliable, avoiding misoperation. While reducing operation time and cost and improving operation efficiency, the stability and accuracy of the intelligent casing isolation floating valve control system are effectively improved.

[0028] Please refer to Figure 2 shown, which is a structural diagram of the drilling section of an embodiment of the present invention, and further includes: The first-stage control unit is respectively connected to the casing control unit and the floating valve monitoring unit, and is used to, when the floating valve is in the open state, according to the casing being in the first drilling section, use the electromagnetic coil to guide the breaking of the blind plate for corresponding actions and straighten the casing. The floating valve blind plate is made of ferromagnetic material. The drilling section includes a first drilling section and a second drilling section, and the first drilling section is located above the second drilling section; The second-stage control unit is respectively connected to the casing control unit and the floating valve monitoring unit, and is used to, when the casing is in the second drilling section and the floating valve is in the open state, vibrate the breaking of the blind plate through the acoustic centralizer and straighten the casing. The broken blind plate is formed by the floating valve blind plate being broken after being impacted.

[0029] In a specific embodiment, please continue to refer to Figure 2 shown, the first drilling section 16 is located above the second drilling section 17, the electromagnetic coil 13 is located in the first drilling section 16, and the acoustic centralizer 14 is located in the second drilling section 17. When the floating valve is in the open state and the casing 15 is in the first drilling section 16, the electromagnetic coil 13 is used to guide the breaking of the blind plate for corresponding actions and straighten the casing 15. When the casing 15 is in the second drilling section 17, the acoustic centralizer 14 is used to vibrate the breaking of the blind plate and straighten the casing.

[0030] It can be understood that in a shallow well, the magnetic field generated by the electromagnetic coil is relatively easy to penetrate the formation and the casing, and the magnetization and correction effects on the casing are relatively direct. Moreover, the construction conditions of a shallow well are relatively simple, and the installation, debugging, and operation of the electromagnetic coil are also relatively convenient, and the casing can be corrected more accurately, which is applicable to the case where the well depth is less than 1000 meters.

[0031] In implementation, use a guiding device to lift the electromagnetic coil and slowly lower it into the wellhead. During the process of lowering it into the well, ensure that the central axis of the coil is aligned with the central axis of the wellbore. Connect the power supply equipment to the electromagnetic coil, check the insulation of the power cord to ensure correct connection, turn on the power to generate a steady magnetic field, generate a fixed magnetic dipole moment through magnetization, and use the magnetic field attraction to pull the casing towards the center of the wellbore. Magnetization time: Continuously power on for 5 - 10 minutes to ensure sufficient magnetization of the casing.

[0032] It can be understood that in deep wells deeper than 1000 meters, through reasonable parameter settings and equipment adjustments, the acoustic centralizer can effectively overcome the absorption and scattering of sound waves by the formation and achieve precise centralization of the casing. For example, by increasing the acoustic emission power, optimizing the acoustic frequency, etc., the propagation effect of the acoustic signal in medium - deep wells can be ensured, thereby accurately detecting the position and attitude of the casing and making corresponding corrections.

[0033] In implementation, lower the acoustic centralizer synchronously with the casing, transmit real - time data through the cable, ensure that the tool string is centered, use the hydraulic push - against arm to push the transmitting and receiving probes against the well wall, alternately transmit longitudinal waves and transverse waves. The longitudinal wave is used for ranging, and the transverse wave is used to determine the azimuth of the casing. Activate the acoustic pusher on the corresponding azimuth and use the acoustic radiation force to push the casing towards the center.

[0034] Specifically, the present invention sets different centralizers for different drilling sections of different depths. While centralizing the casing, it guides the broken blind plate to flow back to the ground along with the drilling fluid. Setting the centralizer to guide the broken blind plate to flow back to the ground can effectively avoid the direct impact of these fragments on downhole equipment, extend the service life of the equipment, reduce the equipment maintenance and replacement costs, reduce the non - production time caused by equipment failures, improve the drilling operation efficiency. Timely guiding the broken blind plate to the ground can keep the drilling fluid circulation system unobstructed, maintain the stability of downhole pressure, ensure the safe progress of drilling operations, and reduce the potential hazards caused by safety accidents to personnel and the environment. During the cementing process, the centralization effect of the casing is crucial for the cementing quality. The centralizer can keep the casing centered in the wellbore, ensure that the cement slurry can be evenly distributed around the casing, form a good cement sheath, improve the sealing performance between the casing and the formation. At the same time, removing the broken blind plate avoids its interference with the cementing operation, helps to ensure the normal flow and setting of the cement slurry, thereby improving the cementing quality, enhancing the stability and sealing performance of the casing, preventing the mutual flow of formation fluids and fluids inside the casing. At the same time, by timely removing the broken blind plate, the risks of these subsequent operations can be reduced, ensuring the smooth progress of various operations, and further enhancing the stability and accuracy of the intelligent casing isolation floating valve control system.

[0035] Specifically, the adjustment unit includes: The shear pin setting sub-unit, which includes a shear pin and is respectively connected to the casing control unit and the float valve monitoring unit, is used to determine whether the casing reaches the working position according to the entering depth, and adjust the shear pin thickness of the float valve for the next drilling or reduce the drilling fluid pressure according to the state of the float valve in the state of determining that the working position has been reached. Among them, If the float valve is in a partially closed state, it is determined to be normal. If the float valve is in a partially open state, it is determined to reduce the drilling fluid pressure. If the float valve is in an open state, it is determined to increase the shear pin thickness of the float valve for the next drilling.

[0036] It can be understood that the shear pin setting sub-unit also includes a pressure relief valve, and part of the drilling fluid is released by opening the pressure relief valve to reduce the pressure.

[0037] It can be understood that the casing control unit can determine the entering depth of the casing through a depth recorder or the drill pipe length accumulation method, and thus determine whether the casing reaches the working position.

[0038] Specifically, the adjustment unit also includes: The drilling fluid adjustment sub-unit, which includes a float valve blank, is respectively connected to the casing control unit and the float valve monitoring unit, and is used to adjust the drilling fluid inflow according to the state of the float valve when the float valve is in a partially open state or a closed state. Among them, If the float valve is in a closed state, it is determined to be normal. If the float valve is in a partially open state, it is determined to reduce the drilling fluid inflow.

[0039] It can be understood that the drilling fluid adjustment sub-unit also includes a variable displacement drilling pump, and the drilling fluid inflow is adjusted by changing the displacement of the variable displacement drilling pump.

[0040] It can be understood that during the descent of the casing, if the float valve is in a partially open state, indicating that the critical blank is broken and the float valve blank is still intact, it is determined that the injected drilling fluid flow rate is too large and the impact force on the blank is too large, so the drilling fluid inflow is reduced.

[0041] Specifically, the adjustment unit also includes: The impact distance setting sub-unit, which includes a firing pin seat and a pressure-bearing seat, is respectively connected to the casing control unit and the float valve monitoring unit, and is used to establish a relationship model between the area ratio and the impact distance by combining the area ratio of the critical blank to the float valve blank and the impact distance, and determine the impact distance corresponding to different area ratios according to the relationship model.

[0042] It can be understood that the impact distance setting sub-unit adjusts the impact distance by changing the relative distance between the firing pin seat and the pressure-bearing seat.

[0043] It can be understood that when the critical blind plate area ratio is larger, it indicates that the floating valve is more sensitive to the control of the fluid under this working condition, and a smaller impact distance may be required to ensure its normal operation and effective control of the fluid; conversely, when the critical blind plate area ratio is smaller, the impact distance can be appropriately increased. The relationship curve between the area ratio and the impact distance can be obtained through experiments on different combinations of blind plates with different area ratios. Select the impact distance corresponding to the area ratio in actual production according to the relationship curve.

[0044] Specifically, the present invention adjusts the relevant components of the floating valve connected to the next drilled casing by using different states of the floating valve during the drilling process of the casing. During the drilling process, different states of the floating valve (such as open, closed, partially open, etc.) reflect the downhole working condition information such as pressure and flow rate. Adjusting the components of the floating valve connected to the next drilled casing according to these states can make the floating valve better adapt to the actual downhole situation, optimize the circulation path and flow rate of the drilling fluid, ensure that the drilling fluid can effectively carry the cuttings back to the surface, improve the drilling efficiency, and at the same time reduce downhole problems caused by poor circulation of the drilling fluid. Reasonably adjusting the components of the floating valve can reduce faults and downtime during the drilling process. When the floating valve can work stably and normally, the drilling operation can be carried out more continuously without frequent handling and adjustment due to floating valve problems. Different formations have different pressures, temperatures and geological characteristics, which will affect the working state of the floating valve. Adjusting the components of the next floating valve according to the state feedback of the floating valve during the drilling process can make it better adapt to different formation conditions, and further improve the stability and accuracy of the intelligent casing isolation floating valve control system.

[0045] Specifically, when the drilling fluid pressure drops, the floating valve monitoring unit compares the drilling fluid return volume with the first preset return volume and the second preset return volume, and determines the state of the floating valve according to the comparison result. If the drilling fluid return volume is less than the first preset return volume, it is determined that the state of the floating valve is the closed state; If the drilling fluid return volume is greater than or equal to the first preset return volume and less than the second preset return volume, it is determined that the state of the floating valve is the partially open state; If the drilling fluid return volume is greater than or equal to the second preset return volume, it is determined that the state of the floating valve is the open state; The first preset return volume is positively correlated with the critical blind plate area, the second preset return volume is positively correlated with the floating valve blind plate area, and the first preset return volume is less than the second preset return volume.

[0046] In a specific embodiment, the first preset return volume is set to 5 cubic meters per hour, and the second preset return volume is set to 10 cubic meters per hour. If the drilling fluid return volume is 1 cubic meter per hour, which is less than the first preset return volume, it is determined that the state of the floating valve is the closed state; If the drilling fluid return volume is 8 cubic meters per hour, which is greater than the first preset return volume and less than the second preset return volume, then the state of the floating valve is determined to be in a partially open state; If the drilling fluid return volume is 12 cubic meters per hour, which is greater than the second preset return volume, then the state of the floating valve is determined to be in an open state; It can be understood that the larger the area of the critical blind plate, the greater the flow rate of the drilling fluid flowing back through the critical blind plate. Therefore, the first preset return volume is positively correlated with the area of the critical blind plate; the larger the area of the floating valve blind plate, the greater the flow rate of the drilling fluid flowing back through the floating valve blind plate. Therefore, the second preset return volume is positively correlated with the area of the floating valve blind plate.

[0047] Specifically, in the state where the casing is in the first drilling section and the floating valve is open, the first control unit generates a magnetic field through the electromagnetic coil to guide the breaking blind plate to leave the casing with the drilling fluid, and in the state where the casing is in the second drilling section and the floating valve is open, guides the breaking blind plate to return to the ground with the drilling fluid.

[0048] Specifically, in the state where the casing is in the second drilling section and the floating valve is open, the second control unit generates a radiation force through the acoustic centralizer to vibrate the breaking blind plate to leave the casing with the drilling fluid.

[0049] Please refer to Figure 3 As shown, it is a structural diagram of the casing isolation floating valve according to an embodiment of the present invention. The present invention provides a casing isolation floating valve based on an intelligent casing isolation floating valve control system, including: A floating valve blind plate 3, which is provided with a critical blind plate for preventing the drilling fluid from overflowing from the casing during the process of the casing entering the well; A striker seat 5, the upper end of which is provided with sharp teeth for breaking the floating valve blind plate by hitting the floating valve blind plate; A pressure-bearing seat 6, which is used to support the floating valve blind plate when the floating valve is in a closed state or a partially open state; A shear pin 7, which is used to fix the striker seat and the pressure-bearing seat when the floating valve is in a closed state or a partially open state.

[0050] In a specific embodiment, the casing isolation floating valve 12 is composed of an upper joint 1, an upper rubber pad 2, a floating valve blind plate 3, a lower rubber pad 4, a striker seat 5, a pressure-bearing seat 6, a shear pin 7, a lower joint 8, a first sealing ring 9, a second sealing ring 10, and a third sealing ring 11, wherein the upper joint 1 and the lower joint 8 are connected by threads, the pressure-bearing seat 6 is arranged on the inner side of the striker seat 5 and connected to the floating valve blind plate 3, the upper rubber pad 2 is respectively connected to the upper joint 1 and the floating valve blind plate 3, the floating valve blind plate 3 is arranged in the upper joint 1, the lower rubber pad 4 is respectively connected to the floating valve blind plate 3 and the pressure-bearing seat 6, the striker seat 5 is connected to the upper joint 1, and the sharp teeth 51 are arranged At the upper end of the striker seat 5, the shear pin 7 is connected to the striker seat 5 and the pressure-bearing seat 6 respectively, the first sealing ring 9 is connected to the floating valve blind plate 3 and the upper joint 1 respectively, the second sealing ring 10 is connected to the striker seat 5 and the pressure-bearing seat 6 respectively, and the third sealing ring 11 is connected to the upper joint 1 and the lower joint 8 respectively; during the casing lowering process, when it is necessary to open the casing isolation floating valve 12, a certain pressure is applied through the wellhead to shear the shear pin 7, so that the floating valve blind plate 3 and the pressure-bearing seat 6 move downward, and the floating valve blind plate 3 hits the sharp teeth at the upper end of the striker seat 5, and the floating valve blind plate 3 is broken by the impact force, thereby opening the casing isolation floating valve 12 to realize the circulation of mud.

[0051] See also Figure 4 As shown, it is a structural diagram of the floating valve blind plate of an embodiment of the present invention. The pressure bearing capacity of the critical blind plate is less than the pressure bearing capacity of the floating valve blind plate. The pressure bearing capacity is the maximum pressure that the blind plate can withstand while remaining intact.

[0052] In a specific embodiment, the critical blind plate 18 is arranged on the floating valve blind plate 3 .

[0053] Specifically, the present invention uses a critical blind plate to be set on the floating valve blind plate, and determines the state of the casing during drilling by detecting the drilling-related parameters of the blind plates with different pressure bearing capacities after they are broken. The blind plates with different pressure bearing capacities will break when subjected to different pressures. By monitoring the breaking of the blind plates, the real-time pressure condition in the casing can be intuitively understood. When a blind plate with a certain pressure bearing capacity breaks, it indicates that the downhole pressure has reached or exceeded the pressure bearing limit of the blind plate. After the blind plate is broken, the flow state of the drilling fluid will change, and related parameters such as the drilling fluid return volume and flow rate will also change accordingly. By detecting these parameters, The data can evaluate the flow of drilling fluid in the casing. The crushing of the blind plate is closely related to the state of the casing during the lowering process. During the casing lowering process, if resistance or other abnormal conditions are encountered, it may cause pressure fluctuations in the casing, thereby affecting the crushing of the blind plate. By analyzing the drilling-related parameters after the blind plate is crushed, it is possible to understand whether the current drilling operation parameters (such as drilling speed, drilling fluid density, etc.) are reasonable. If the blind plate crushing is found to be abnormal, it may be necessary to adjust the drilling parameters to adapt to the actual situation downhole, further improving the stability and accuracy of the intelligent casing isolation floating valve control system.

[0054] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easily understood by those skilled in the art that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0055] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An intelligent casing isolation floating valve control system, characterized in that, Comprising: A casing control unit for installing a floating valve on the casing, controlling the installed casing to enter the wellbore and recording the entry depth; A pressure detection unit connected to the casing control unit for detecting the drilling fluid pressure inside the casing; A flow rate detection unit connected to the casing control unit for detecting the drilling fluid return volume; A floating valve monitoring unit respectively connected to the pressure detection unit and the flow rate detection unit for determining the state of the floating valve by combining the drilling fluid pressure and the drilling fluid return volume, and the state of the floating valve includes floating valve open, floating valve closed, and floating valve partially open; An adjustment unit respectively connected to the casing control unit and the floating valve monitoring unit for adjusting the shear pin thickness of the floating valve entering the wellbore next time or reducing the drilling fluid pressure by combining the entry depth and the state of the floating valve, adjusting the drilling fluid entry volume according to the state of the floating valve, and adjusting the impact distance based on the area of the critical blind plate, where the critical blind plate is provided on the floating valve blind plate; 2. The intelligent casing isolation floating valve control system according to claim 1, wherein Further comprising: A first section control unit respectively connected to the casing control unit and the floating valve monitoring unit for, when the floating valve is in the open state, guiding the breaking of the blind plate by using an electromagnetic coil to perform corresponding actions and straightening the casing according to the casing in the first drilling section, where the floating valve blind plate is made of ferromagnetic material, and the wellbore section includes the first drilling section and the second drilling section, and the first drilling section is located above the second drilling section; A second section control unit respectively connected to the casing control unit and the floating valve monitoring unit for, when the casing is in the second drilling section and the floating valve is in the open state, vibrating the broken blind plate by using an acoustic straightener and straightening the casing, where the broken blind plate is formed by the floating valve blind plate being broken after being impacted; 3. The intelligent casing isolation floating valve control system according to claim 2, wherein The adjustment unit includes: A shear pin setting sub-unit including shear pins, respectively connected to the casing control unit and the floating valve monitoring unit for determining whether the casing reaches the working position according to the entry depth, and adjusting the shear pin thickness of the floating valve entering the wellbore next time or reducing the drilling fluid pressure according to the state of the floating valve in the state of determining that it reaches the working position, where if the floating valve is in the partially open state, it is determined to reduce the drilling fluid pressure; if the floating valve is in the open state, it is determined to increase the shear pin thickness of the floating valve entering the wellbore next time.

4. The intelligent casing isolation floating valve control system according to claim 3, wherein The adjustment unit further includes: A drilling fluid adjustment sub-unit including the floating valve blind plate, respectively connected to the casing control unit and the floating valve monitoring unit for adjusting the drilling fluid entry volume according to the state of the floating valve when the floating valve is in the partially open state or the closed state, where if the floating valve is in the partially open state, it is determined to reduce the drilling fluid entry volume.

5. The intelligent casing isolation floating valve control system according to claim 4, characterized in that The adjustment unit further includes: The impact distance setting sub-unit, which includes a firing pin seat and a pressure-bearing seat, is respectively connected to the casing control unit and the floating valve monitoring unit, and is used to establish a relationship model between the area ratio of the critical blind plate to the floating valve blind plate and the impact distance, and determine the impact distance corresponding to different area ratios according to the relationship model.

6. The intelligent casing isolation floating valve control system according to claim 5, wherein When the drilling fluid pressure drops, the floating valve monitoring unit compares the amount of drilling fluid discharged back with a first preset discharge amount and a second preset discharge amount, and determines the state of the floating valve according to the comparison result. The first preset discharge amount is positively correlated with the area of the critical blind plate, the second preset discharge amount is positively correlated with the area of the floating valve blind plate, and the first preset discharge amount is less than the second preset discharge amount.

7. The intelligent casing isolation floating valve control system according to claim 6, wherein, When the casing is in the first drilling section and the floating valve is open, the first section control unit generates a magnetic field through an electromagnetic coil to guide the broken blind plate to leave the casing with the drilling fluid, and when the casing is in the second drilling section and the floating valve is open, guides the broken blind plate to return to the ground with the drilling fluid.

8. The intelligent casing isolation floating valve control system according to claim 7, characterized in that, When the casing is in the second drilling section and the floating valve is open, the second section control unit generates a radiation force through an acoustic centralizer to vibrate the broken blind plate to leave the casing with the drilling fluid.

9. A casing isolation floating valve using the intelligent casing isolation floating valve control system according to any one of claims 1-8, characterized in that, Comprising: A floating valve blind plate, which is provided with a critical blind plate to prevent drilling fluid from overflowing from the casing during the process of the casing entering the well. A firing pin seat, the upper end of which is provided with sharp teeth to break the floating valve blind plate by impacting the floating valve blind plate. A pressure-bearing seat, which is used to support the floating valve blind plate when the floating valve is in the closed state or the partially open state. A shear pin, which is used to fix the firing pin seat and the pressure-bearing seat when the floating valve is in the closed state or the partially open state.

10. The casing isolation floating valve according to claim 9, characterized in that, The pressure-bearing capacity of the critical blind plate is less than that of the floating valve blind plate, and the pressure-bearing capacity is the maximum pressure that the blind plate can withstand while remaining intact.

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