Open hole plugging well completion device for complex well

Abstract

The invention relates to the technical field of oil and gas exploitation, and discloses a complex well open hole plugging well completion device which comprises a casing pipe, an end socket in threaded connection with the top of the casing pipe, an end socket in threaded connection with the bottom of the casing pipe and an annular sinking groove formed in the side wall of the casing pipe. A rubber sleeve is fixedly arranged at the position, located at the annular sinking groove, of the side wall of the sleeve, a first feeding opening is formed in the position, located below the annular sinking groove, of the inner wall of the sleeve, a pipe groove is formed in the side wall of the sleeve, and the two ends of the pipe groove communicate with the annular sinking groove and the first feeding opening correspondingly; a supporting frame is arranged on the inner wall of the sleeve, a first pressure spring is fixedly connected to the top of the supporting frame, and a movable sleeve is fixed to the tail end of the first pressure spring. The stress limit of the pin shaft and the stress of the connecting sleeve are dynamically calculated through the pump pressure real-time adjusting system, precise closed-loop control of the pump pressure is achieved in combination with a temperature compensation model and pressure drop loss compensation, and the problems of pin failure and pressure overshoot caused by temperature change of a traditional device are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas production, and in particular relates to a complex well open hole plugging and completion device. Background Art

[0002] In the oil and gas exploration sector, openhole well completion technology often faces the challenge of sealing irregular wellbore walls in complex formations. As the core sealing component of openhole plugging systems, the expansion reliability of the rubber cartridge directly determines the effectiveness of the annular cement seal. This creates a permanent zonal seal, prevents fluid crossflow, and safeguards wellbore integrity. Traditional rubber cartridge expansion relies on a mechanical mechanism triggered by cement injection pressure, making dynamic control accuracy crucial to plugging success.

[0003] The current mainstream technology uses a shear pin-controlled rubber expansion mechanism, which triggers the opening and closing of the feed port by pre-setting the pin shear strength, and uses cement pressure to push the rubber cartridge to expand. However, this type of static design has inherent flaws. Downhole temperature changes significantly weaken the pin shear strength, but existing devices cannot sense temperature changes in real time, resulting in premature shearing of the pin or delayed failure. Dynamic parameters such as pump pressure, cement rheology, and rubber cartridge back pressure are not included in closed-loop control. Pressure overshoot often causes the rubber cartridge to not fully expand, thus prematurely closing the feed port. Mechanical triggering lacks feedback and regulation of key parameters such as drilling fluid flow and cement volume, and is prone to plugging failure due to fluid fluctuations.

[0004] The fundamental flaw of existing devices lies in their lack of real-time control capabilities for coordinated multi-parameter adjustments. While the shear strength of the pin is strongly correlated with temperature, the static design model fails to establish a temperature-strength decay relationship, resulting in inaccurate shear timing. Pressure drop losses during cement injection are not dynamically compensated, causing actual stress on the pin to deviate from theoretical values. Furthermore, the stress state of key components cannot be accurately monitored, leading to delayed pump pressure regulation. This often results in insufficient expansion of the rubber cartridge, leading to annular seal failure, or cement backflow blocking the flow channel, significantly increasing operational risks and costs. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a complex well open hole plugging and completion device, aiming to solve the problems raised by the background technology.

[0006] The application is achieved, a complex well open hole plugging completion device, including casing, and the top of the casing is threadedly connected with an end head, and the bottom of the casing is threadedly connected with an end head, and the bottom of the end head is provided with an opening, further comprising: an annular groove is arranged on the side wall of the casing, a rubber sleeve is fixedly arranged on the side wall of the casing at the annular groove, and a feeding port one is arranged on the inner wall of the casing below the annular groove; a pipe groove is arranged in the side wall of the casing, and the two ends of the pipe groove are communicated with the annular groove and the feeding port one respectively; a support frame is arranged on the inner wall of the casing, a compression spring one is fixedly connected to the top of the support frame, a moving sleeve is fixed to the end of the compression spring one, the moving sleeve is slidingly connected in the casing, the compression spring one pushes the moving sleeve to block the feeding port one, a connecting sleeve is fixedly connected to the moving sleeve through a pin shaft, and a plugging ball is movably connected to the upper end of the connecting sleeve; further comprising a pump pressure real-time adjusting system for adjusting the pressure of the drilling fluid supplied by the delivery pump in real time, comprising: an information acquisition module for acquiring pump pressure, real-time flow of drilling fluid into the casing, total volume of drilling fluid into the casing and temperature of the pin shaft; a pin shaft state evaluation module for constructing a pin shaft state evaluation model based on the temperature information of the pin shaft to output real-time stress limit data of the pin shaft; a connecting sleeve stress processing module for constructing a connecting sleeve stress calculation model based on pump pressure, real-time flow of drilling fluid into the casing and total volume of drilling fluid into the casing to output real-time total stress borne by the connecting sleeve; a pump pressure adjusting module for constructing a pump pressure adjusting model based on real-time stress limit data of the pin shaft and real-time total stress borne by the connecting sleeve to output target pump pressure and adjust the current pump pressure to the target pump pressure.

[0007] Further technical solutions, the inner bottom of the end head is fixed with an extension rod, the top of the extension rod is fixed with a plug, the bottom of the plug is fixedly provided with a compression spring four, the end of the compression spring four is connected with the inner bottom of the end head, and a fixed ring is fixed to the inner wall of the end head, which is located above the plug.

[0008] Further technical solutions, a guide sliding groove is horizontally arranged in the support frame, a guide block is slidingly connected in the guide sliding groove, a compression spring three is fixed to the end of the guide block away from the axis of the casing, the compression spring three is connected with the inner wall of the guide sliding groove, a limiting groove is arranged on the inner wall of the casing, a protrusion matched with the limiting groove is arranged on the end of the guide block away from the axis of the casing, an extension leg is arranged at the bottom of the connecting sleeve, the extension leg is matched with the side wall of the connecting sleeve and the guide block, and a plugging assembly is arranged in the side wall of the casing, which blocks the feeding port one after the connecting sleeve and the extension leg are separated from the support frame.

[0009] A further technical solution is that the sealing assembly includes an annular guide groove arranged in the side wall of the sleeve, a sealing sleeve is slidably connected in the annular guide groove, a second compression spring is arranged at the bottom of the sealing sleeve, the end of the second compression spring is connected to the bottom of the annular guide groove, and a second feed port and a limiting hole are arranged on the side wall of the sealing sleeve, the second feed port cooperates with the first feed port, and the limiting hole cooperates with the protrusion on the guide block.

[0010] Further technical solutions, pump pressure regulation model:

[0011]

[0012]

[0013] in, is the target pump pressure, is the safety factor, It is the real-time force limit data of the pin. is the top area of ​​the connecting sleeve, is the pump pressure, is the static pressure of drilling fluid, Cement static pressure, is the pressure drop loss, For the back pressure of the rubber sleeve, To adjust the pressure difference, is the proportional coefficient, used to adjust the amplitude, is the current pump pressure.

[0014] Further technical solutions, pin state assessment model:

[0015]

[0016]

[0017] in, The real-time force limit data of the pin, that is, the maximum shear force that the pin can withstand, is the temperature-dependent shear strength, is the cross-sectional area of ​​the pin, is the number of pins, is the reference temperature Shear strength under is the temperature coefficient, is the ambient temperature, is the reference temperature for shear strength.

[0018] Further technical solutions, connecting sleeve force calculation model:

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] in, is the total stress borne by the connecting sleeve in real time, B is the top area of ​​the connecting sleeve, is the pump pressure, is the static pressure of drilling fluid, Cement static pressure, Pressure drop loss is the pressure loss caused by the viscosity of the fluid and the local resistance of the orifice when cement flows from the casing through the feed port into the rubber cylinder. The rubber sleeve has elasticity, and when cement is injected, the rubber sleeve expands and generates reverse pressure. is the drilling fluid density, is the acceleration due to gravity, is the drilling fluid height, is the density of cement, Cement height, is the total volume of drilling fluid entering the casing, is the internal cross-sectional area of ​​the casing, The height of the top of the connecting sleeve from the wellhead.

[0025] Further technical solutions, the specific calculation model of pressure drop loss is:

[0026]

[0027] in, is the pressure drop loss, coefficient of friction, is the equivalent length, i.e. the equivalent length of the feed inlet to the flow channel, is the hydraulic diameter, which is the equivalent diameter that characterizes the flow capacity of the flow channel. is the density of cement, is the cement flow rate, the average flow rate of cement at the feed inlet.

[0028] Further technical solutions, the specific calculation model of the rubber sleeve back pressure is:

[0029]

[0030] The minimum starting pressure for cement injection into the rubber cylinder. is the rubber cylinder stiffness, The total volume of cement injected into the rubber cartridge, that is, the volume of drilling fluid entering the casing .

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] The complex well open hole plugging completion device provided by the present application dynamically calculates the stress limit of the pin shaft and the stress of the connecting sleeve through pump compaction time adjustment system, combines a temperature compensation model and a pressure drop loss compensation, realizes precise closed-loop control of pump compaction, solves the problems of pin failure and pressure overshoot caused by temperature change of the traditional device, and has the advantages of improving the reliability of rubber tube expansion and guaranteeing the integrity of annular sealing. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view;

[0034] Figure 2 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view; Figure 1 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view;

[0035] Figure 3 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view; Figure 2 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view;

[0036] Figure 4 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view; Figure 3 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view;

[0037] Figure 5 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view; Figure 4 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view;

[0038] Figure 6 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view. Figure 4 The complex well open hole plugging completion device provided by the present application has the structure shown in the schematic view.

[0039] In the drawings: 1, sleeve; 2, end head; 3, end head; 4, rubber tube; 5, annular groove; 6, pipe groove; 7, feeding port one; 8, support frame; 9, compression spring one; 10, moving sleeve; 11, connecting sleeve; 12, pin shaft; 13, annular guide groove; 14, plugging sleeve; 15, compression spring two; 16, feeding port two; 17, guide block; 18, compression spring three; 19, limiting groove; 20, extension leg; 21, limiting hole; 22, telescopic rod; 23, fixing ring; 24, blocking block; 25, compression spring four; 26, plugging ball; 27 guide chute. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application clearer, further detailed description will be made to the present application in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application.

[0041] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0042] like Figures 1-5 As shown, a complex well open hole plugging and completion device provided by one embodiment of the present invention includes a casing 1, an end head 2 threadedly connected to the top of the casing 1, and a sealing head 3 threadedly connected to the bottom of the casing 1, wherein the bottom of the end head 2 is provided with an opening, and further includes: an annular groove 5 is provided on the side wall of the casing 1, a rubber cylinder 4 is fixedly provided at the annular groove 5 on the side wall of the casing 1, a feed port 7 is provided on the inner wall of the casing 1 below the annular groove 5, and a pipe groove 6 is provided in the side wall of the casing 1. The two ends of the tube groove 6 are respectively connected with the annular sink 5 and the feed port 7; a support frame 8 is provided on the inner wall of the sleeve 1, and a compression spring 9 is fixedly connected to the top of the support frame 8. A movable sleeve 10 is fixed to the end of the compression spring 9. The movable sleeve 10 is slidably connected in the sleeve 1, and the compression spring 9 pushes the movable sleeve 10 to block the feed port 7. A connecting sleeve 11 is fixedly connected to the movable sleeve 10 through a pin shaft 12, and a blocking ball 26 is movably connected to the upper end of the connecting sleeve 11.

[0043] When the casing 1 is in use, the compression spring 9 moves the sleeve 10 upward, and the movable sleeve 10 blocks the feed port 7. The connecting sleeve 11 is fixed in the movable sleeve 10 by the pin 12. The movable sleeve 10 and the connecting sleeve 11 are both provided with horizontal pin holes for installing the pin 12. The casing 1 is placed in the well, and the sealing ball 26 is put into the casing 1. The casing 1 blocks the through hole in the middle of the connecting sleeve 11. The movable sleeve 10, the connecting sleeve 11 and the sealing ball 26 separate the middle of the casing 1. Cement is injected into the casing 1, and then the plug is extended from the top of the casing 1. Then, drilling fluid is injected into the top of the casing 1. As the drilling fluid is injected, the pressure generated by the drilling fluid pushes the plug downward, and the cement pressure at the bottom of the plug increases. The cement pressure overcomes the elastic force of the compression spring 9 and pushes the movable sleeve 10 downward. When the movable sleeve 10 is lower than the feed port 7 , the feed port 7 is opened, and cement is injected into the annular trough 5 through the feed port 7 and the pipe groove 6. As the amount of cement in the annular trough 5 increases, the rubber cylinder 4 is stretched and expanded until it contacts the well wall to achieve seat sealing. As the drilling fluid is continuously injected, the cement pressure continues to increase, and the downward pushing force of the connecting sleeve 11 and the sealing ball 26 continues to increase. The pin 12 is cut off by the connecting sleeve 11 and the movable sleeve 10, and the fixed connection between the movable sleeve 10 and the connecting sleeve 11 disappears. The connecting sleeve 11 and the sealing ball 26 fall off from the movable sleeve 10, and the cement moves downward from the middle of the connecting sleeve 11 and is finally discharged from the opening at the bottom of the head 3. When the connecting sleeve 11 and the sealing ball 26 fall off from the movable sleeve 10, the pressure on the top of the movable sleeve 10 decreases, and the compression spring 9 pushes the movable sleeve 10 to move upward and block the feed port 7 to prevent the cement in the annular trough 5 from flowing back into the casing 1.

[0044] The rubber sleeve 4 is the core sealing element of the sealing device, and its expansion reliability directly affects the cementing effect of the annular space. The traditional technology relies on preset shear pins to control the expansion of the rubber sleeve, but the temperature change downhole will significantly weaken the strength of the pins, resulting in inaccurate timing of shearing.

[0045] Therefore, a pump compaction real-time adjustment system is also included for real-time adjustment of the pressure of the drilling fluid supplied by the delivery pump, comprising:

[0046] An information acquisition module is configured to acquire pump pressure, real-time flow of the drilling fluid into the casing 1, total volume of the drilling fluid into the casing 1, and temperature of the pin shaft 12.

[0047] A pin shaft state evaluation module is configured to construct a pin shaft state evaluation model based on the temperature information of the pin shaft 12 to output real-time stress limit data of the pin shaft.

[0048] A connection sleeve stress processing module is configured to construct a connection sleeve stress calculation model based on the pump pressure, real-time flow of the drilling fluid into the casing 1, and total volume of the drilling fluid into the casing 1 to output real-time total stress borne by the connection sleeve.

[0049] A pump pressure adjustment module is configured to construct a pump pressure adjustment model based on the real-time stress limit data of the pin shaft and the real-time total stress borne by the connection sleeve to output a target pump pressure and adjust the current pump pressure to the target pump pressure.

[0050] The pin shaft state evaluation model refers to a shear strength calculation model based on temperature changes, and can specifically use a temperature sensor to collect pin shaft temperature in real time and calculate real-time shear strength threshold through a linear regression equation. The connection sleeve stress calculation model refers to a stress calculation model that comprehensively considers fluid static pressure and dynamic pressure drop, and can specifically use Bernoulli's equation combined with fluid mechanics formulas to calculate the axial force borne by the connection sleeve in real time.

[0051] Specifically, the information acquisition module collects pump pressure, flow, volume, and temperature data in real time. The pin shaft state evaluation module dynamically corrects the shear strength threshold of the pin according to the temperature data, and the connection sleeve stress processing module calculates the total stress borne by the connection sleeve 11 based on real-time flow to calculate the fluid static pressure and pressure drop loss. The pump pressure adjustment module compares the total stress with the strength threshold of the pin shaft 12 and dynamically adjusts the delivery pump pressure through a target pump pressure formula, so that the stress borne by the connection sleeve 11 is always lower than the real-time strength limit of the pin shaft 12.

[0052] Compared with the existing technology, the traditional device uses a fixed shear pin strength value, which cannot compensate for the strength attenuation caused by temperature, resulting in premature shearing of the pin shaft 12 in a high temperature environment or delayed triggering at a low temperature. This solution ensures that the timing of shearing of the pin shaft 12 is accurately matched with the expansion requirements of the rubber cylinder 4 through real-time temperature monitoring and dynamic strength correction. The existing technology does not consider the impact of the dynamic changes in fluid parameters on the force on the connecting sleeve 11. This solution uses real-time flow and volume monitoring, combined with pressure drop loss calculation, to accurately control the pump pressure so that the rubber cylinder 4 obtains the continuous pressure required for full expansion. The traditional mechanical trigger mechanism lacks closed-loop control. This solution realizes multi-parameter coordinated control through the pump pressure regulation system, effectively avoiding sealing failure caused by pressure overshoot.

[0053] Through the above technical solution, the present application can correct the pin shear strength threshold in real time, eliminate the influence of temperature changes on the triggering timing; dynamically compensate for the pressure deviation caused by fluid parameter fluctuations to ensure that the rubber cylinder 4 obtains a stable expansion pressure; and achieve a dynamic balance between the pump pressure and the force on the components through a closed-loop control system to avoid the problem of triggering the lockout before the rubber cylinder 4 is fully expanded, thereby significantly improving the reliability and sealing effect of the open hole well plugging.

[0054] Pin condition assessment model:

[0055] The pin force limit model is:

[0056]

[0057]

[0058] in, The pin's real-time force limit data, i.e., the maximum shear force that the pin 12 can withstand, refers to the maximum shear force that the pin system can withstand at the current temperature. Specifically, this can be obtained by using a temperature sensor to collect ambient temperature data in real time and combining it with material mechanical parameters. This data is used to dynamically correct the pin's 12 load capacity threshold to prevent strength deviations from the design value due to temperature changes. The temperature-dependent shear strength refers to the functional relationship between the shear strength of the pin material and temperature. Specifically, the shear strength values ​​at different temperatures can be obtained through material testing, and the temperature coefficient can be determined by fitting a linear equation. is the temperature-dependent shear strength, is the cross-sectional area of ​​the pin, which can be achieved by measuring the diameter of the pin 12 and calculating the circular area. is the number of pins, is the reference temperature Shear strength under is the temperature coefficient (usually a negative value, indicating that the strength decreases with increasing temperature), is the ambient temperature, The reference temperature for shear strength is usually 20°C, which can be set based on material manuals or experimental data.

[0059] Specifically, the pin state evaluation model dynamically updates the effective shear strength of the pin material by collecting real-time downhole temperature data and substituting the temperature value into the temperature-related shear strength function. For example, when the downhole temperature rises to 80°C, if the temperature coefficient is -1.2 MPa / °C, the shear strength attenuation is 300 + (-1.2) x (80-20) = 228 MPa. Combined with the cross-sectional area and number of the pin 12, the maximum allowable shear force at the current temperature can be calculated. Through the temperature compensation mechanism, the pin shear 12 break trigger condition is dynamically adjusted with the ambient temperature, ensuring that the pin 12 will not shear prematurely due to strength attenuation in high temperature environments, or delay triggering due to excessive strength in low temperature environments.

[0060] Compared with the prior art, the traditional method designs the pin with a fixed shear strength without considering the influence of downhole temperature fluctuations on material performance. For example, in high temperature well sections, the actual strength of the pin may be reduced by 30% compared to the design value, causing premature shearing and triggering the rubber sleeve 4 to not fully expand. The present scheme establishes a temperature-strength correlation model to real-time correct the bearing limit of the pin 12, so that the shear trigger pressure always matches the current working condition, overcoming the temperature sensitivity defect of static design.

[0061] Through the above technical scheme, the present application realizes dynamic calibration of the pin shear strength, ensuring that the rubber sleeve expansion trigger timing accurately matches the downhole temperature condition. The specific effects include: in high temperature environments, by reducing the allowable shear force threshold of the pin, premature shearing caused by material strength attenuation is avoided; in low temperature environments, by increasing the threshold, insufficient rubber sleeve expansion caused by delayed triggering is prevented. Thus, the sealing failure problem caused by temperature changes is solved, and the reliability of the open hole sealing device is improved.

[0062] Connection sleeve stress calculation model:

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] wherein, To bear the total stress in real time, the specific method can be realized by combining a pressure sensor and a stress calculation module, which converts the pump pressure, fluid static pressure and dynamic loss into mechanical stress for judging the shearing time of the pin, B is the area of the top of the connecting sleeve 11, which can be calculated by using the geometric parameters of the annular section, and its function is to convert the pressure parameter into force to establish a direct correlation between the pump pressure and the mechanical stress, For pump pressure, it can be obtained by a pressure sensor, For drilling fluid static pressure, For cement static pressure, For pressure drop loss, when the cement flows into the rubber sleeve 4 from the feed port 7 in the casing 1, due to the fluid viscosity, local resistance of the orifice and other factors, the pressure loss is generated, For rubber sleeve counter pressure, the rubber sleeve 4 itself has elasticity, and the expansion of the rubber sleeve 4 when injecting cement will generate counter pressure, For drilling fluid density, For gravity acceleration, For drilling fluid height, For cement density, Cement height, For the total volume of the drilling fluid entering the casing 1, For the cross-sectional area of the inside of the casing 1, The top of the connecting sleeve 11 is away from the height of the wellhead.

[0069] Specifically, the technical scheme dynamically calculates the stress borne by the connecting sleeve 11 through a multi-parameter coupled mechanical model. In the process of pumping cement, the pump pressure, drilling fluid volume flow and temperature data are collected in real time, the injection volume is converted into liquid column height, and then the drilling fluid static pressure and the cement static pressure are calculated. At the same time, the is calculated based on the fluid viscosity, flow rate and flow channel geometric parameters, and the is calculated in combination with the rubber sleeve stiffness model. Finally, all dynamic parameters are integrated to output the real-time total stress. When approaches the pin shearing strength threshold, the pump pressure adjustment module is triggered to dynamically adjust the pump pressure, so as to ensure that the pin 12 is sheared within the predetermined stress range.

[0070] Compared with the prior art, the traditional method only relies on the static pin strength design and does not consider the strength attenuation caused by temperature and dynamic pressure loss, resulting in a deviation of more than 30% in the shearing time. By introducing the pressure drop loss compensation term and the rubber sleeve counter pressure , the stress calculation error is controlled within 5%, and through the dynamic conversion of and , the real-time update of the liquid column static pressure is realized, and the problem of static pressure calculation lag caused by the change of injection volume is solved.

[0071] Through the technical scheme, the present application solves the stress calculation deviation caused by ignoring dynamic pressure loss and rubber sleeve counter pressure of the traditional device, avoids the insufficient expansion of the rubber sleeve caused by the early shearing of the pin 12 or the cement backflow caused by the delayed shearing, and ensures the stress calculation accuracy of the connecting sleeve by real-time association of pump pressure, flow, volume parameters and mechanical model, so that the shearing time of the pin 12 and the expansion demand of the rubber sleeve are strictly matched, and the risk of plugging failure is reduced by more than 40%

[0072] The specific calculation model of pressure drop loss is:

[0073]

[0074] wherein, is the pressure drop loss, is the friction coefficient, is the equivalent length, that is, the equivalent length of the inlet 1-7 flow channel, is the hydraulic diameter, which represents the equivalent diameter of the flow channel, is the cement density, is the cement flow rate, which is the average flow rate of the cement at the inlet 1-7;

[0075] when the flow is laminar (Re<2000) when the flow is turbulent (Re≥2000) , Re is the Reynolds number, , is the cement viscosity, is the cement flow rate, , is the volume flow, that is, the real-time flow rate of the well fluid into the casing 1, is the number of inlets 1-7, is the area of a single hole of the inlet 1-7.

[0076] Among them, pressure drop loss refers to the energy loss caused by friction and local resistance when the fluid flows in the flow channel. Specifically, it can be achieved by using the Darcy-Weisbach formula combined with the dynamic calculation of the Reynolds number, which is used to accurately quantify the pressure loss during the cement flow process. Among them, the equivalent length refers to the parameter that equates the local resistance of the flow channel to the length of the straight pipe section. Specifically, it can be achieved through the measurement of the flow channel structure parameters or the calibration of fluid mechanics simulation, and is used to convert the complex flow channel geometric characteristics into a calculable equivalent length. Among them, the hydraulic diameter refers to the equivalent diameter that characterizes the flow capacity of the non-circular flow channel. Specifically, it can be achieved by calculating the ratio of four times the flow cross-sectional area to the wetted perimeter, and is used to correct the flow resistance characteristics of the special-shaped flow channel. Among them, the friction coefficient refers to a dimensionless parameter that reflects the friction between the fluid and the flow channel wall. Specifically, it can be achieved by judging the flow state through the Reynolds number and then selecting the corresponding correlation formula to calculate, and is used to distinguish the different energy dissipation laws under laminar and turbulent conditions. Among them, the Reynolds number refers to a dimensionless number that characterizes the ratio of the fluid's inertial force to its viscous force. It can be achieved through the coupling calculation of cement density, flow velocity, hydraulic diameter, and viscosity parameters, and is used to dynamically judge the flow state and select the friction coefficient calculation mode.

[0077] Specifically, by acquiring cement flow, density and viscosity parameters in real time, combined with the number of feed ports and single hole area data, the average flow velocity of cement in the flow channel is dynamically calculated. The Reynolds number is calculated based on the flow velocity, hydraulic diameter and viscosity to determine the flow state, and the corresponding friction coefficient calculation model is selected according to the flow state. The equivalent length, hydraulic diameter, friction coefficient and flow velocity are substituted into the pressure drop loss formula to output the pressure drop loss value under the current working conditions in real time. This calculation process ensures the accuracy of resistance calculation under laminar and turbulent states through the state-specific friction coefficient selection mechanism; through the multi-parameter coupling calculation of the Reynolds number, it dynamically reflects the impact of changes in fluid viscosity, density and flow velocity on the flow state; and through the real-time feedback mechanism of flow velocity, it eliminates model errors caused by flow fluctuations or structural differences.

[0078] Compared with existing technologies, which use fixed empirical coefficients to estimate pressure drop, fail to distinguish between flow pattern differences, and ignore the influence of flow path structural parameters, resulting in pump pressure regulation errors. This solution establishes a pressure drop calculation model that incorporates flow pattern assessment, structural parameter correction, and real-time flow rate feedback to dynamically compensate for changes in flow resistance. This solves the problem of inaccurate pin force calculations caused by traditional static models that fail to consider local resistance and flow pattern changes.

[0079] Through the above technical solution, the present application can dynamically correct the pressure drop loss according to the real-time working conditions, ensure the calculation accuracy of the stress borne by the pin in the pump pressure regulation model, avoid insufficient expansion of the rubber cylinder or cement backflow due to pressure loss estimation deviation, thereby improving the reliability of the sealing mechanism action and the integrity of the annulus seal.

[0080] The specific calculation model of the rubber sleeve back pressure is:

[0081]

[0082] the minimum initial pressure for cement injection into the sleeve 4, the stiffness of the sleeve 4, the thin-walled sphere assumption, the elastic modulus, t is the thickness, and R is the radius of the casing 1, the total volume of cement injected into the sleeve 4, i.e., the volume of drilling fluid entering the casing 1

[0083] wherein the minimum initial pressure refers to the static resistance that needs to be overcome by the sleeve 4 when it is initially inflated, and can be realized by calibrating the critical pressure value of sleeve deformation through a material compression test, to ensure that the sleeve 4 can start effective inflation at the initial stage of injection. The stiffness of the sleeve refers to the ability of the sleeve 4 to resist deformation during inflation, and can be realized by using the stiffness formula derived from the thin-walled spherical shell elastic deformation theory , which converts the geometric parameters of the sleeve into a calculable stiffness coefficient through the quantitative relationship of the elastic modulus, thickness, and radius. The injection volume refers to the cumulative amount of cement injected into the sleeve, which can be realized by monitoring the total volume of drilling fluid entering the casing in real time through a flowmeter , to dynamically characterize the feedback effect of the inflation degree of the sleeve 4 on the back pressure.

[0084] Specifically, the technical scheme decomposes the sleeve back pressure into two parts, static initial pressure and dynamic stiffness compensation, and establishes a linear relationship between the back pressure and the injection volume. At the initial stage of cement injection, the minimum initial pressure ensures that the sleeve 4 overcomes the initial deformation resistance to start inflation; as the injection volume increases, the stiffness term quantifies the back pressure increment due to elastic deformation in the inflation process of the sleeve 4 in real time through the geometric relationship of the elastic modulus of the sleeve material, thickness, and casing radius. The stiffness model of the thin-walled sphere assumption simplifies the three-dimensional inflation of the sleeve into an axisymmetric deformation problem, enabling the stiffness calculation to be based on measurable material parameters and structural dimensions. The pump pressure regulation system dynamically corrects the target pump pressure according to the back pressure model, compensates for the effect of sleeve 4 inflation on the pin force, thereby avoiding premature shearing or delayed failure of the pin due to the fact that the back pressure is not calculated in real time.

[0085] In some specific embodiments, the elastic modulus can be obtained through a tensile test of rubber material, such as using the ASTM D412 standard to test the stress-strain curve of the sleeve material; the thickness t can be calibrated by an ultrasonic thickness gauge before the casing 1 is lowered into the well; the injection volume The drilling fluid pump-in amount can be collected in real time by the electromagnetic flowmeter.

[0086] Compared with the prior art, the existing rubber sleeve counter pressure calculation only considers the fixed initial pressure and does not establish a dynamic correlation between the counter pressure and the injection volume, resulting in calculation errors of the pin shear force. The scheme introduces a stiffness compensation term, quantifies the elastic deformation characteristics of the rubber sleeve as a function proportional to the injection volume, so that the counter pressure calculation can reflect the inflation state of the rubber sleeve 4 in real time. The force deviation problem of the pin caused by ignoring the stiffness change of the rubber sleeve 4 in the prior art is solved by the thin-walled ball model and flow monitoring in the scheme.

[0087] Through the above technical scheme, the dynamic counter pressure generated in the inflation process of the rubber sleeve can be accurately compensated, so that the pump pressure adjustment system adjusts the target pressure value according to the real-time injection volume, thereby accurately controlling the pin shear force within the safety threshold. This avoids the rubber sleeve 4 from being prematurely locked or incompletely inflated due to the non-dynamic correction of the counter pressure, ensures the integrity of the annular cementing, and prevents the cement from flowing back and blocking the flow passage.

[0088] Pump pressure adjustment model:

[0089]

[0090]

[0091] Wherein, The target pump pressure is the optimal pump pressure value calculated dynamically according to the real-time working condition, which can be specifically calculated by collecting the pin shaft temperature, drilling fluid flow and volume data in real time, combining the rubber sleeve inflation counter pressure and flow passage pressure drop loss, and used to ensure that the pin shear stress does not exceed the strength threshold after temperature attenuation, The safety factor is a redundancy parameter used to adjust the target pump pressure, which can be specifically an empirical value or dynamically adjusted based on historical data, and used to compensate for model calculation errors and working condition fluctuations, The pin shaft real-time force limit data is the maximum shear strength of the pin at the real-time temperature, which can be specifically calculated by collecting the environmental temperature through the temperature sensor, combining the linear relationship model of material strength and temperature, and used to dynamically correct the failure threshold of the pin, The top area of the connecting sleeve 11 is A, The pump pressure is P, The drilling fluid static pressure is Pw, The cement static pressure is Pc, The pressure drop loss is the pressure loss generated when the cement flows from the casing 1 into the rubber sleeve 4 through the inlet 7 due to fluid viscosity, local resistance of the orifice and the like, which can be specifically obtained by calculating the flow rate, Reynolds number and friction coefficient through fluid mechanics formula, and used to compensate for the influence of flow passage resistance on the actual pump pressure, The sleeve back pressure is the reverse pressure generated by the elastic deformation of the rubber sleeve during the expansion process, which can be calculated by the product of the rubber sleeve stiffness and the injection volume, and is used to reflect the real-time feedback of the rubber sleeve expansion state to the pump pressure, The differential pressure is adjusted, The proportional coefficient is used to adjust the amplitude, The current pump pressure is adjusted.

[0092] Specifically, the pump pressure adjustment model dynamically calculates the stress limit of the pin shear strength after attenuation by real-time acquisition of pin temperature, drilling fluid flow and volume data, and determines the target pump pressure in combination with drilling fluid static pressure, cement static pressure, flow passage pressure drop and rubber sleeve back pressure. The calculation of the target pump pressure takes the pin stress limit as the reference, adjusts the upper limit of the pressure through the safety factor, deducts the liquid column static pressure to eliminate its interference on the pin stress, superimposes the pressure drop loss to compensate the flow passage resistance, and introduces the rubber sleeve back pressure to reflect the expansion stiffness. The adjustment differential pressure controls the pump pressure adjustment amplitude through the proportional coefficient, avoiding system oscillation caused by sudden pressure change. For example, when the temperature rise causes the pin shear strength to decrease, the model automatically reduces the target pump pressure to prevent overpressure shearing; when the rubber sleeve expansion stiffness increases, the model increases the target pump pressure to maintain the net pressure required for expansion.

[0093] Compared with the prior art, the traditional technology relies on the preset static pin shear strength to trigger pump pressure control, without considering the dynamic changes of strength attenuation caused by temperature and rubber sleeve expansion back pressure, resulting in pump pressure adjustment lag or misalignment. The present scheme establishes a dynamic model coupled with multiple parameters, integrates temperature, flow, volume and rheological parameters in real time, realizes accurate matching of pump pressure with pin stress limit and rubber sleeve expansion state, and solves the problem that static threshold control cannot adapt to complex downhole conditions.

[0094] Through the above technical scheme, the present application can dynamically compensate the weakening effect of temperature change on pin shear strength, avoid the pin 12 from being sheared prematurely or delayed due to high temperature, real-time correct the flow passage pressure drop and rubber sleeve back pressure, ensure that the pump pressure accurately acts on the rubber sleeve 4 expansion process, prevent insufficient expansion caused by pressure overshoot, realize gradual adjustment of the pump pressure through proportional adjustment, maintain system stability, and ultimately improve the reliability and success rate of open hole plugging.

[0095] As shown in Figures 1-3 As a preferred embodiment of the present application, the inner bottom of the end head 2 is fixed with a telescopic rod 22, the top of the telescopic rod 22 is fixed with a plug 24, the bottom of the plug 24 is fixed with a compression spring four 25, the end of the compression spring four 25 is connected with the inner bottom of the end head 2, the inner wall of the end head 2 is fixed with a fixed ring 23, and the fixed ring 23 is located above the plug 24.

[0096] In the embodiment of the present application, in the initial state, the compression spring four 25 pushes the telescopic rod 22 to extend, the telescopic rod 22 drives the blocking block 24 to contact the bottom of the fixed ring 23, and then seals the through hole in the middle of the fixed ring 23; when the cement pressure at the upper end of the fixed ring 23 overcomes the elastic force of the compression spring four 25 and pushes the blocking block 24 to move downward, the telescopic rod 22 retracts, the cement at the top of the fixed ring 23 flows from the through hole in the middle of the fixed ring 23 to the lower side of the fixed ring 23, the cement is discharged through the opening at the bottom of the sealing head 3, the drilling fluid supply is stopped, the rubber plug stops moving, the compression spring four 25 pushes the telescopic rod 22 to extend, the telescopic rod 22 drives the blocking block 24 to contact the bottom of the fixed ring 23, and then seals the through hole in the middle of the fixed ring 23, thereby avoiding the backflow of the cement outside the sealing head 3.

[0097] As shown in Figure 4 and Figure 5 , as a preferred embodiment of the present application, a guide chute 27 is horizontally arranged in the support frame 8, a guide block 17 is slidably connected in the guide chute 27, a compression spring three 18 is fixed to the end of the guide block 17 away from the axis of the sleeve 1, the compression spring three 18 is connected with the inner wall of the guide chute 27, a limiting groove 19 is arranged on the inner wall of the sleeve 1, a protrusion is arranged on the end of the guide block 17 away from the axis of the sleeve 1 and matched with the limiting groove 19, an extension leg 20 is arranged at the bottom of the connecting sleeve 11, the extension leg 20 is matched with the guide block 17 and the side wall of the connecting sleeve 11, and a plugging assembly is arranged in the side wall of the sleeve 1; after the connecting sleeve 11 and the extension leg 20 are separated from the support frame 8, the plugging assembly plugs the feeding port one 7.

[0098] In the embodiment of the present application, in the initial state, the extension leg 20 blocks the end of the guide block 17, the compression spring three 18 is in a compressed state, and the protrusion at the end of the guide block 17 is inserted into the limiting groove 19; by matching the protrusion at the end of the guide block 17 with the limiting groove 19, the movement of the support frame 8 along the length direction of the sleeve 1 is limited.

[0099] When the pin shaft 12 is broken and the connecting sleeve 11 and the extension leg 20 are pushed by the cement pressure to the lower side of the support frame 8, the block at the end of the guide block 17 disappears, the compression spring three 18 pushes the guide block 17 to move, the guide block 17 is pushed by the compression spring three 18 to move, the protrusion at the end of the guide block 17 is completely separated from the limiting groove 19, the movement limitation of the support frame 8 is removed, the rubber plug pushes the moving sleeve 10 and the support frame 8 to move downward, and then the rubber plug pushes the cement in the sleeve 1 downward, thereby reducing the cement residue in the sleeve 1 and facilitating subsequent operation; after the connecting sleeve 11 and the extension leg 20 are separated from the support frame 8, the plugging assembly plugs the feeding port one 7, thereby preventing the cement between the annular groove 5 and the rubber cylinder 4 from flowing back into the sleeve 1 and ensuring the sealing effect of the rubber cylinder 4.

[0100] As shown in Figure 4 and Figure 6As shown, as a preferred embodiment of the present application, the plugging assembly comprises an annular guide groove 13 arranged in the sidewall of the sleeve 1, a plugging sleeve 14 is slidably connected in the annular guide groove 13, a compression spring 15 is arranged at the bottom of the plugging sleeve 14, the end of the compression spring 15 is connected with the bottom of the annular guide groove 13, a feeding port 16 and a limiting hole 21 are arranged on the sidewall of the plugging sleeve 14, the feeding port 16 cooperates with the feeding port 7, and the limiting hole 21 cooperates with the protrusion on the guide block 17.

[0101] In the embodiment of the present application, in the initial state, the extension leg 20 blocks the end of the guide block 17, the compression spring 18 is in the compressed state, the protrusion at the end of the guide block 17 is inserted into the limiting hole 21 on the plugging sleeve 14, the protrusion at the end of the guide block 17 cooperates with the limiting recess 19 to limit the movement of the support frame 8 along the length direction of the sleeve 1, and the protrusion at the end of the guide block 17 cooperates with the limiting hole 21 on the plugging sleeve 14 to limit the movement of the plugging sleeve 14, at this time, the compression spring 15 is in the compressed state (as shown in Figure 4 and Figure 6 The feeding port 16 coincides with the feeding port 7.

[0102] When the pin shaft 12 is broken and the connecting sleeve 11 and the extension leg 20 are pushed to the lower side of the support frame 8 by the cement pressure, the block at the end of the guide block 17 disappears, the compression spring 18 pushes the guide block 17 to move, the protrusion at the end of the guide block 17 is first separated from the limiting hole 21 on the plugging sleeve 14, the compression spring 15 pushes the plugging sleeve 14 upward by the elastic force, the feeding port 16 on the plugging sleeve 14 is dislocated from the feeding port 7, the plugging sleeve 14 blocks the feeding port 7, thereby closing the feeding port 7, the compression spring 18 continuously pushes the guide block 17 to move, after the protrusion at the end of the guide block 17 is completely separated from the limiting recess 19, the movement limitation of the support frame 8 is released, the rubber plug pushes the movement sleeve 10 and the support frame 8 to move downward, thereby facilitating the rubber plug to push the cement inside the sleeve 1 downward, so as to reduce the cement residue in the sleeve 1 and facilitate the subsequent operation.

[0103] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A complex well open hole plugging and completion device, comprising a casing, an end head threadedly connected to the top of the casing, and a head threadedly connected to the bottom of the casing, wherein the bottom of the end head is provided with an opening, characterized in that: Also includes: An annular groove is provided on the side wall of the casing, a rubber cylinder is fixedly provided at the annular groove on the side wall of the casing, a feed port 1 is provided on the inner wall of the casing below the annular groove, a pipe groove is provided in the side wall of the casing, and both ends of the pipe groove are respectively connected to the annular groove and the feed port 1; A support frame is provided on the inner wall of the sleeve, a compression spring 1 is fixedly connected to the top of the support frame, a movable sleeve is fixed to the end of the compression spring 1, the movable sleeve is slidably connected in the sleeve, the compression spring 1 pushes the movable sleeve to block the feed port 1, a connecting sleeve is fixedly connected to the movable sleeve through a pin shaft, and a blocking ball is movably connected to the upper end of the connecting sleeve; It also includes a real-time pump pressure adjustment system for real-time adjustment of the pressure of the drilling fluid supplied by the delivery pump, including: An information acquisition module is used to obtain the pump pressure, the real-time flow rate of the drilling fluid entering the casing, the total volume of the drilling fluid entering the casing, and the temperature of the pin shaft; The pin state assessment module builds a pin state assessment model based on the pin temperature information and outputs the pin's real-time force limit data; The connecting sleeve stress processing module builds a connecting sleeve stress calculation model based on the pump pressure, the real-time flow rate of drilling fluid entering the casing, and the total volume of drilling fluid entering the casing to output the total stress borne by the connecting sleeve in real time; The pump pressure regulation module constructs a pump pressure regulation model based on the real-time force limit data of the pin shaft and the real-time total stress borne by the connecting sleeve to output the target pump pressure and adjust the current pump pressure to the target pump pressure.

2. The complex well open hole plugging and completion device according to claim 1, characterized in that: A telescopic rod is fixed to the inner bottom of the end head, a block is fixed to the top of the telescopic rod, a compression spring four is fixed to the bottom of the block head, the end of the compression spring four is connected to the inner bottom of the end head, a fixing ring is fixed to the inner wall of the end head, and the fixing ring is located above the block head.

3. The complex well open hole plugging and completion device according to claim 1, characterized in that: A guide slot is horizontally arranged in the support frame, and a guide block is slidably connected in the guide slot. A compression spring three is fixed to the end of the guide block away from the axis of the sleeve, and the compression spring three is connected to the inner wall of the guide slot. A limiting groove is arranged on the inner wall of the sleeve, and a protrusion that cooperates with the limiting groove is arranged at the end of the guide block away from the axis of the sleeve. An extension leg is provided at the bottom of the connecting sleeve, and the extension leg cooperates with the side wall of the connecting sleeve and the guide block. A blocking component is provided in the side wall of the sleeve. After the connecting sleeve and the extension leg are separated from the support frame, the blocking component blocks the feed port.

4. The complex well open hole plugging and completion device according to claim 3 is characterized in that: The sealing assembly includes an annular guide groove arranged in the side wall of the sleeve, a sealing sleeve is slidably connected in the annular guide groove, a second compression spring is arranged at the bottom of the sealing sleeve, the end of the second compression spring is connected to the bottom of the annular guide groove, and a second feed port and a limiting hole are arranged on the side wall of the sealing sleeve, the second feed port cooperates with the first feed port, and the limiting hole cooperates with the protrusion on the guide block.

5. The complex well open hole plugging and completion device according to claim 1, characterized in that: Pump pressure regulation model: in, is the target pump pressure, is the safety factor, It is the real-time force limit data of the pin. is the top area of ​​the connecting sleeve, is the pump pressure, is the static pressure of drilling fluid, Cement static pressure, is the pressure drop loss, For the back pressure of the rubber sleeve, To adjust the pressure difference, is the proportional coefficient, used to adjust the amplitude, is the current pump pressure.

6. The complex well open hole plugging and completion device according to claim 5, characterized in that: Pin condition assessment model: in, The real-time force limit data of the pin, that is, the maximum shear force that the pin can withstand, is the temperature-dependent shear strength, is the cross-sectional area of ​​the pin, is the number of pins, is the reference temperature Shear strength under is the temperature coefficient, is the ambient temperature, is the reference temperature for shear strength.

7. The complex well open hole plugging and completion device according to claim 5, characterized in that: Connecting sleeve force calculation model: in, is the total stress borne by the connecting sleeve in real time, B is the top area of ​​the connecting sleeve, is the pump pressure, is the static pressure of drilling fluid, Cement static pressure, Pressure drop loss is the pressure loss caused by the viscosity of the fluid and the local resistance of the orifice when cement flows from the casing through the feed port into the rubber cylinder. The rubber sleeve has elasticity, and when cement is injected, the rubber sleeve expands and generates reverse pressure. is the drilling fluid density, is the acceleration due to gravity, is the drilling fluid height, is the density of cement, Cement height, is the total volume of drilling fluid entering the casing, is the internal cross-sectional area of ​​the casing, The height of the top of the connecting sleeve from the wellhead.

8. The complex well open hole plugging and completion device according to claim 7, characterized in that: The specific calculation model for pressure drop loss is: in, is the pressure drop loss, coefficient of friction, is the equivalent length, i.e. the equivalent length of the feed inlet to the flow channel, is the hydraulic diameter, which is the equivalent diameter that characterizes the flow capacity of the flow channel. is the density of cement, is the cement flow rate, the average flow rate of cement at the feed inlet.

9. The complex well open hole plugging and completion device according to claim 7, characterized in that: The specific calculation model of the rubber sleeve back pressure is: The minimum starting pressure for cement injection into the rubber cylinder. is the rubber cylinder stiffness, The total volume of cement injected into the rubber cartridge, that is, the volume of drilling fluid entering the casing .

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