A complex well open hole plugging completion device

Abstract

The application relates to the technical field of oil and gas exploitation, and discloses a complex well open-hole plugging completion device, which comprises a sleeve, a head threadedly connected to the top of the sleeve and a sealing head threadedly connected to the bottom of the sleeve, an opening is arranged at the bottom of the head, and the device further comprises an annular groove arranged on the side wall of the sleeve, a rubber cylinder fixedly arranged on the side wall of the sleeve at the annular groove, a feeding port one arranged on the inner wall of the sleeve below the annular groove, a pipe groove arranged in the side wall of the sleeve, and the two ends of the pipe groove are communicated with the annular groove and the feeding port one respectively, a support frame arranged on the inner wall of the sleeve, a compression spring one fixedly connected to the top of the support frame, and a moving sleeve fixed to the tail end of the compression spring one. The pump pressure real-time adjustment system dynamically calculates the stress limit of a pin shaft and the stress of a connecting sleeve, temperature compensation models and pressure drop loss compensation are combined, pump pressure precise closed-loop control is realized, and the problems of pin failure and pressure overshoot caused by temperature change of a traditional device are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas exploitation, and particularly relates to a complex well open hole plugging completion device. BACKGROUND

[0002] In the field of oil and gas exploitation, the open hole well completion technology often faces the problem of irregular well wall sealing in complex formations. As the core sealing element of the open hole plugging device, the expansion reliability of the rubber tube directly determines the annular cementing effect. Permanent interlayer isolation is formed to prevent fluid channeling and ensure wellbore integrity. The traditional rubber tube expansion relies on the cement injection pressure to trigger the mechanical mechanism, and the dynamic control precision becomes the key to the success or failure of plugging.

[0003] The current mainstream technology uses a rubber tube expansion mechanism controlled by a shear pin, which triggers the opening and closing of the feed port by presetting the shear strength of the pin, and uses the cement pressure to push the rubber tube to expand. However, such static design has inherent defects, and the significant change in downhole temperature significantly weakens the shear strength of the pin, but the existing device cannot sense the temperature change in real time, resulting in premature pin shearing or delayed failure; dynamic parameters such as pump pressure, cement rheology, and rubber tube back pressure are not included in the closed-loop control, and the rubber tube often does not fully expand due to pressure overshoot, causing the feed port to close prematurely. Mechanical triggering lacks feedback 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 defect of the existing device is the lack of real-time regulation and control of multiple parameters: the shear strength of the pin is strongly related to the temperature, but the static design model does not establish the temperature-strength decay relationship, resulting in inaccurate shearing time; the cement injection stage does not dynamically compensate for pressure drop loss, resulting in a stress acting on the pin that deviates from the theoretical value; the stress state of the key components cannot be fed back in real time, and the pump pressure adjustment lags. This often leads to insufficient rubber tube expansion, resulting in annular sealing failure, or cement backflow blocking the flow passage, significantly increasing the operation risk and cost. SUMMARY

[0005] The purpose of the embodiments of the application is to provide a complex well open hole plugging completion device to solve the problems raised in the background art.

[0006] This invention is implemented as follows: a complex well open-hole plugging and completion device includes a casing, a threaded end cap at the top of the casing, and a threaded end cap at the bottom of the casing. The end cap has an opening at its bottom. The device further includes: an annular groove on the sidewall of the casing; a rubber sleeve fixedly mounted on the sidewall of the casing at the annular groove; a feed inlet located below the annular groove on the inner wall of the casing; a pipe groove inside the sidewall of the casing, with its two ends communicating with the annular groove and the feed inlet, respectively; a support frame on the inner wall of the casing; a compression spring fixedly connected to the top of the support frame; a movable sleeve fixedly attached to the end of the compression spring; the movable sleeve slidably connected inside the casing; the compression spring pushes the movable sleeve to block the feed inlet; and a connecting sleeve fixedly connected inside the movable sleeve by a pin. The upper end of the connecting sleeve is movably connected to a sealing ball; it also includes a real-time pump pressure adjustment system for real-time adjustment of the pressure supplied by the delivery pump to the drilling fluid, comprising: an information acquisition module for acquiring 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; a pin shaft condition assessment module for constructing a pin shaft condition assessment model based on the pin shaft temperature information and outputting real-time pin shaft stress limit data; a connecting sleeve stress processing module for constructing a connecting sleeve stress calculation model based on the pump pressure, the real-time flow rate of the drilling fluid entering the casing, and the total volume of the drilling fluid entering the casing and outputting the real-time total stress borne by the connecting sleeve; and a pump pressure adjustment module for constructing a pump pressure adjustment model based on the real-time pin shaft stress limit data and the real-time total stress borne by the connecting sleeve, outputting a target pump pressure and adjusting the current pump pressure to the target pump pressure.

[0007] A further technical solution is provided, wherein a telescopic rod is fixed to the bottom of the end head, a block is fixed to the top of the telescopic rod, a compression spring is fixed to the bottom of the block, the end of the compression spring is connected to the bottom of the end head, and a fixing ring is fixed to the inner wall of the end head, the fixing ring being located above the block.

[0008] A further technical solution includes a horizontally arranged guide groove inside the support frame, a guide block slidably connected inside the guide groove, a compression spring three fixed at the end of the guide block away from the sleeve axis, the compression spring three being connected to the inner wall of the guide groove, a limiting groove provided on the inner wall of the sleeve, a protrusion cooperating with the limiting groove at the end of the guide block away from the sleeve axis, an extension leg provided at the bottom of the connecting sleeve, the extension leg cooperating with the guide block and the side wall of the connecting sleeve, and a sealing component provided inside the side wall of the sleeve. After the connecting sleeve and the extension leg are disengaged from the support frame, the sealing component blocks the feed inlet.

[0009] A further technical solution includes an annular guide groove provided inside the side wall of the sleeve, a sealing sleeve slidably connected inside the annular guide groove, a second compression spring provided at the bottom of the sealing sleeve, the end of the second compression spring being connected to the bottom of the annular guide groove, a second feed inlet and a limiting hole provided on the side wall of the sealing sleeve, the second feed inlet cooperating with the first feed inlet, and the limiting hole cooperating with a protrusion on the guide block.

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

[0011]

[0012]

[0013] in, For the target pump pressure, For safety reasons, This provides real-time stress limit data for the pin shaft. The area of ​​the top of the connecting sleeve. For pump pressure, For drilling fluid static pressure, For cement static pressure, To reduce pressure loss, For the rubber sleeve back pressure, To adjust the pressure difference, This is a proportional coefficient used to adjust the amplitude. This is the current pump pressure.

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

[0015]

[0016]

[0017] in, This represents the real-time stress limit data of the pin, i.e., the maximum shear force the pin can withstand. Temperature-dependent shear strength, The cross-sectional area of ​​the pin is... For the number of pins, Reference temperature Shear strength below, For temperature coefficient, For ambient temperature, The reference temperature for shear strength.

[0018] Further technical solutions include a stress calculation model for the connecting sleeve:

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] in, To ensure the connecting sleeve bears the total stress in real time, B is the top area of ​​the connecting sleeve. For pump pressure, For drilling fluid static pressure, For cement static pressure, The pressure drop loss is the pressure loss that occurs when cement flows into the rubber cylinder from the casing through the inlet, due to fluid viscosity, local resistance at the orifice, etc. The rubber sleeve provides back pressure; the sleeve itself is elastic, and when cement is injected, the sleeve expands, generating reverse pressure. For drilling fluid density, It is the acceleration due to gravity. For drilling fluid level, The density of cement, Cement height, This refers to the total volume of drilling fluid entering the casing. The internal cross-sectional area of ​​the sleeve. The height of the top of the connecting sleeve from the wellhead.

[0025] A further technical solution, the specific calculation model for pressure drop loss is as follows:

[0026]

[0027] in, To reduce pressure loss, coefficient of friction Equivalent length, i.e., the equivalent length of the feed inlet channel. The hydraulic diameter is the equivalent diameter that characterizes the flow capacity of the channel. The density of cement, Cement flow velocity is the average flow velocity of cement at the inlet.

[0028] A further technical solution, the specific calculation model for the rubber sleeve back pressure is as follows:

[0029]

[0030] The minimum starting pressure for injecting cement into the injection cartridge. For the rigidity of the rubber sleeve, The total volume of cement injected into the casing is the volume of drilling fluid that enters 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 do not limit the present application.

[0041] The following describes the specific implementation of the present invention in detail in conjunction with specific embodiments.

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

[0043] In the embodiment of the present invention, during use, the casing 1 is assembled. At this time, the first compression spring 9 moves the moving sleeve 10 upward, and the moving sleeve 10 blocks the first feed port 7. The connecting sleeve 11 is fixed inside the moving sleeve 10 through the pin shaft 12. Horizontal pin holes are provided on both the moving sleeve 10 and the connecting sleeve 11 for installing the pin shaft 12; the casing 1 is placed into the well, the plugging ball 26 is put into the casing 1, the casing 1 blocks the through hole in the middle of the connecting sleeve 11, and the moving sleeve 10, the connecting sleeve 11, and the plugging ball 26 separate the middle part of the casing 1. Cement is injected into the casing 1, and then a rubber plug is inserted from the top of the casing 1, and 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 rubber plug downward, and the cement pressure at the bottom of the rubber plug increases. The cement pressure overcomes the elastic force of the first compression spring 9 and pushes the moving sleeve 10 downward. When the moving sleeve 10 is lower than the first feed port 7, the first feed port 7 is opened, and the cement is injected into the annular sink 5 through the first feed port 7 and the pipe groove 6. As the cement in the annular sink 5 increases, the rubber cylinder 4 is enlarged and expanded until it contacts the well wall to achieve setting. As the drilling fluid is continuously injected, the cement pressure continuously increases, and the downward driving force of the connecting sleeve 11 and the plugging ball 26 continuously increases. The pin shaft 12 is cut off by the connecting sleeve 11 and the moving sleeve 10, and the fixed connection between the moving sleeve 10 and the connecting sleeve 11 disappears. The connecting sleeve 11 and the plugging ball 26 fall off from the moving sleeve 10, and the cement moves downward from the middle of the connecting sleeve 11 and finally discharges from the opening at the bottom of the head 3. When the connecting sleeve 11 and the plugging ball 26 fall off from the moving sleeve 10, the pressure at the top of the moving sleeve 10 decreases, and the first compression spring 9 pushes the moving sleeve 10 upward to block the first feed port 7, preventing the cement in the annular sink 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 prior art, the traditional device uses a fixed shear pin strength value and 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 low temperatures. This solution ensures that the shearing timing of the pin shaft 12 precisely matches the expansion requirement of the rubber barrel 4 through real-time temperature monitoring and dynamic strength correction. The prior art does not consider the influence of dynamic changes in fluid parameters on the force borne by the connecting sleeve 11. This solution precisely controls the pump pressure to enable the rubber barrel 4 to obtain the continuous pressure required for sufficient expansion through real-time flow rate and volume monitoring and combined with pressure drop loss calculation. The traditional mechanical triggering mechanism lacks closed-loop control. This solution realizes multi-parameter collaborative control through the pump pressure regulation system, effectively avoiding seal failure caused by pressure overshoot.

[0053] Through the above technical solutions, this application can real-time correct the pin shear strength threshold, eliminate the influence of temperature changes on the triggering timing; dynamically compensate for the pressure deviation caused by fluid parameter fluctuations, ensure that the rubber barrel 4 obtains a stable expansion pressure; realize the dynamic balance of pump pressure and component force through a closed-loop control system, avoid the problem of triggering the lock before the rubber barrel 4 is fully expanded, and significantly improve the reliability and sealing effect of open-hole well plugging.

[0054] Pin shaft state evaluation model:

[0055] The pin force limit model is:

[0056]

[0057]

[0058] Where, is the real-time force limit data of the pin shaft, that is, the maximum shear force that the pin shaft 12 can bear, which refers to the maximum shear force that the pin system can bear at the current temperature. Specifically, the ambient temperature data can be real-time collected by a temperature sensor and calculated in combination with the material mechanics parameters. This data is used to dynamically correct the bearing capacity threshold of the pin 12, avoiding strength deviation from the design value due to temperature changes. Among them, the temperature-related 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 tests, and the temperature coefficient can be determined by fitting a linear equation. is the temperature-related shear strength, is the cross-sectional area of the pin, which can be specifically realized by measuring the diameter of the pin 12 and calculating the circular area. is the number of pins, [[ID=​​​​​​​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] The pressure drop loss refers to the energy loss of the fluid flowing in the flow channel due to friction and local resistance, which can be dynamically calculated by using the Darcy-Weisbach formula combined with the Reynolds number, and is used to accurately quantify the pressure loss in the cement flow process. The equivalent length refers to a parameter for equivalent to the length of a straight pipe section for local resistance of the flow channel, which can be realized by measuring or simulating the structure parameters of the flow channel, and is used to convert the geometric characteristics of the complex flow channel into a calculable equivalent length. The hydraulic diameter refers to an equivalent diameter for characterizing the flow capacity of a non-circular flow channel, which can be calculated by using the ratio of four times the flow area to the wet perimeter, and is used to correct the flow resistance characteristics of the special-shaped flow channel. The friction coefficient refers to a dimensionless parameter reflecting the friction between the fluid and the wall surface of the flow channel, which can be calculated by selecting the corresponding correlation formula after judging the flow state by the Reynolds number, and is used to distinguish the different energy dissipation laws in the laminar and turbulent flow states. The Reynolds number refers to a dimensionless number representing the ratio of inertial force to viscous force of the fluid, which can be calculated by coupling the parameters of cement density, flow rate, hydraulic diameter and viscosity, and is used to dynamically judge the flow state and select the friction coefficient calculation mode.

[0077] Specifically, by real-time acquisition of the cement flow rate, density and viscosity parameters, combined with the number of feeding ports and single-hole area data, the average flow rate of the cement in the flow channel is dynamically calculated. The Reynolds number is calculated based on the flow rate, hydraulic diameter and viscosity to judge 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 rate are substituted into the pressure drop loss formula to output the pressure drop loss value in the current working condition in real time. The calculation process ensures the accuracy of the resistance calculation in the laminar and turbulent flow states through the state-dependent friction coefficient selection mechanism, dynamically reflects the influence of the changes of fluid viscosity, density and flow rate on the flow state through the multi-parameter coupling calculation of the Reynolds number, and eliminates the model error caused by flow fluctuations or structural differences through the real-time feedback mechanism of the flow rate.

[0078] Compared with the prior art, the prior art uses fixed empirical coefficients to estimate the pressure drop loss, does not distinguish the flow state difference and ignores the influence of the flow channel structure parameters, resulting in pump pressure regulation deviation. The present scheme establishes a pressure drop calculation model including flow state judgment, structure parameter correction and real-time flow feedback, realizes dynamic compensation of flow resistance changes, and solves the problem of inaccurate calculation of the force borne by the pin due to the failure of the traditional static model to consider local resistance and flow state transition.

[0079] Through the above technical scheme, the present application can dynamically correct the pressure drop loss according to the real-time working condition, ensure the calculation accuracy of the force borne by the pin in the pump pressure regulation model, avoid insufficient expansion of the rubber sleeve or reverse flow of the cement due to estimation deviation of the pressure loss, and thus improve the reliability of the action of the sealing mechanism and the integrity of the annular seal.

[0080] The specific calculation model of the rubber sleeve counter 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] where 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 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 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 static initial pressure and dynamic stiffness compensation, establishing a linear relationship between back pressure and 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 through the geometric relationship of the elastic modulus of the sleeve material, the thickness and the radius of the casing. 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 connecting sleeve 11 and the guide block 17, 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 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 three 18 pushes the guide block 17 to move, the guide block 17 is pushed to move by the compression spring three 18, 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 completion device comprising a casing, and a threaded top end and a threaded bottom end, the bottom of the top end being provided with an opening, characterized in that, Also include: The sleeve side wall is provided with an annular groove, the sleeve side wall is fixedly provided with a rubber tube at the annular groove, the sleeve inner wall is provided with a feeding port one below the annular groove, the sleeve side wall is provided with a pipe groove, and the two ends of the pipe groove are communicated with the annular groove and the feeding port one respectively; The inner wall of the sleeve is provided with a support frame, the top of the support frame is fixedly connected with a compression spring one, the end of the compression spring one is fixedly connected with a moving sleeve, the moving sleeve is slidably connected in the sleeve, the compression spring one pushes the moving sleeve to block the feeding port one, the moving sleeve is fixedly connected with a connecting sleeve through a pin shaft, and the upper end of the connecting sleeve is movably connected with a blocking ball; Also include 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 sleeve, total volume of drilling fluid into the sleeve, 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 sleeve, and total volume of drilling fluid into the sleeve 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.

2. The complex well open hole plug and abandonment completion device of claim 1, wherein, The inner bottom of the end is fixedly connected with an extension rod, the top of the extension rod is fixedly connected with a blocking block, the bottom of the blocking block is fixedly connected with a compression spring four, the end of the compression spring four is connected with the inner bottom of the end, the inner wall of the end is fixedly connected with a fixed ring, and the fixed ring is located above the blocking block.

3. The complex well open hole plug and abandonment completion device of claim 1, wherein, The support frame is horizontally provided with a guide sliding groove, the guide sliding groove is slidably connected with a guide block, the end of the guide block away from the shaft center of the sleeve is fixedly connected with a compression spring three, the compression spring three is connected with the inner wall of the guide sliding groove, the inner wall of the sleeve is provided with a limiting groove, the end of the guide block away from the shaft center of the sleeve is provided with a protrusion matched with the limiting groove, the bottom of the connecting sleeve is provided with an extension leg, the extension leg is matched with the connecting sleeve side wall and the guide block, and the sleeve side wall is provided with a blocking assembly.

4. The complex well open hole plug and abandonment completion device of claim 3, wherein, The blocking assembly comprises an annular guide groove provided in the sleeve side wall, the annular guide groove is slidably connected with a blocking sleeve, the bottom of the blocking sleeve is provided with a compression spring two, the end of the compression spring two is connected with the inner bottom of the annular guide groove, the side wall of the blocking sleeve is provided with a feeding port two and a limiting hole, the feeding port two is matched with the feeding port one, and the limiting hole is matched with the protrusion on the guide block.

5. The complex well open hole plug and abandonment completion device of claim 1, wherein, Pump pressure adjusting model: Wherein, is the target pump pressure, is the safety factor, is the pin shaft real-time force limit data, is the connecting sleeve top area, is the pump pressure, is the drilling fluid static pressure, is the cement static pressure, is the pressure drop loss, is the rubber sleeve counter pressure, is the adjustment pressure difference, is the proportional coefficient, used to adjust the amplitude, is the current pump pressure.

6. The complex well open hole plug and abandonment completion device of claim 5, wherein, Pin shaft state evaluation model: wherein, is the pin shaft real-time force limit data, i.e. the maximum shear force that the pin shaft can withstand, is the temperature-dependent shear strength, is the pin cross-sectional area, is the number of pins, is the reference temperature is the shear strength at the reference temperature, is the temperature coefficient, is the ambient temperature, is the reference temperature for the shear strength.

7. The complex well open hole plug and abandonment completion device of claim 5, wherein, Connecting sleeve stress calculation model: Wherein, B is the area of the top of the connecting sleeve, P is the pump pressure, Pc is the static pressure of the drilling fluid, Pc is the static pressure of the cement, Pd is the pressure drop loss, when the cement flows from the inside of the casing through the inlet port into the rubber sleeve, due to fluid viscosity, local resistance of the orifice, etc., a pressure loss is generated, P is the rubber sleeve counter pressure, the rubber sleeve itself has elasticity, and when the cement is injected, the expansion of the rubber sleeve will generate a reverse pressure, Pd is the density of the drilling fluid, g is the acceleration of gravity, H is the height of the drilling fluid, Pc is the density of the cement, Hc is the height of the cement, V is the total volume of the drilling fluid entering the casing, A is the cross-sectional area inside the casing, The top of the connecting sleeve is the distance from the wellhead height.

8. The complex well open hole plug and abandonment completion device of claim 7, wherein, The specific calculation model of pressure drop loss is: wherein, is the pressure drop loss, is the friction factor, is the equivalent length, i.e. the length of the flow path equivalent to the length of the inlet, is the hydraulic diameter, i.e. the equivalent diameter characterizing the flow capacity of the flow path, is the cement density, is the cement flow rate, i.e. the average flow rate of the cement at the inlet.

9. The complex well open hole plug and abandonment completion device of claim 7, wherein, The specific calculation model of rubber sleeve back pressure is: minimum starting pressure for cement injection, cement sheath stiffness, total volume of cement injected into the sheath, i.e. the volume of drilling fluid that entered the casing .

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