A method of post-jet vibratory solid guide pipe construction

Abstract

The application discloses a kind of jetting post-vibration solid guide pipe construction methods belonging to deepwater oil exploration technical field.The method includes the following steps: assembling guide pipe sending tool, low pressure well head, jetting drilling tool, vibration device and guide pipe;Jetting drilling tool sprays drilling fluid, while guide pipe is sequentially passed through seawater, seabed mud line, seabed rock layer and lowered to the depth of interest, and cuttings are generated around jetting drilling tool;Start vibration device, adjust to the optimal standing time of guide pipe and corresponding vibration frequency and vibration time, and drive guide pipe to vibrate, propagate vibration wave to surrounding soil to consolidate it, and improve the vertical bearing capacity of guide pipe;Close vibration device, and let guide pipe stand until its vertical bearing capacity and total floating weight of sending system maintain static force balance;Release sending system, and raise jetting drilling tool, vibration device and guide pipe sending tool and recover.The application shortens the standing time of guide pipe, thereby shortens the installation time of jetting down guide pipe, and improves the installation speed.

Description

Technical Field

[0001] This invention relates to the field of deepwater oil exploration technology, and in particular to a method for constructing a post-jetting vibration-stabilized conduit. Background Technology

[0002] Jetting installation of guide pipes is currently the most common construction method in deepwater drilling, characterized by simple procedures, short construction time, and safety and environmental friendliness. However, the comprehensive daily cost of the on-site platform for deepwater guide pipe installation can reach several million yuan. The guide pipe jetting installation time mainly includes the jetting drilling time and the settling time. Given a fixed jetting drilling time, the guide pipe jetting installation time depends on the settling time. Determining the guide pipe settling time plays a crucial role in the drilling process. If the jetting settling time is too short, it can lead to insufficient vertical load-bearing capacity of the guide pipe, easily causing subsea wellhead sinking, and in severe cases, preventing subsequent production operations. If the settling time is too long, it will increase production costs.

[0003] Therefore, a post-jetting vibration-stabilized guide pipe construction method is needed to reasonably shorten the guide pipe installation and settling time and reduce the cost of deep water drilling. Summary of the Invention

[0004] The purpose of this invention is to provide a method for constructing a post-jetting vibration-stabilized conduit, comprising the following steps:

[0005] Step A1: Assemble the guide pipe insertion tool, low-pressure wellhead, jetting drill string, vibratory device, and guide pipe;

[0006] Step A2: The jetting drill bit injects drilling fluid, and at the same time, the guide pipe is lowered to the target depth by passing through seawater, seabed mudline, and seabed rock strata in sequence, and rock cuttings are generated around the jetting drill bit.

[0007] Step A3: Start the vibration device, adjust it to the optimal static time of the guide pipe and the corresponding vibration frequency and vibration time, and drive the guide pipe to vibrate, so as to spread the vibration wave to the surrounding soil to consolidate it and improve the vertical bearing capacity of the guide pipe.

[0008] Step A4: Turn off the vibration device and allow the conduit to stand still until its vertical bearing capacity and the total buoyant weight of the system are in static balance;

[0009] Step A5: Disconnect the feed system, lift up the jetting drill, vibratory device, and guide tube feed tool, and retrieve them.

[0010] The optimal settling time for the catheter is calculated as follows:

[0011] Step B1: Obtain the soil parameters for the specific seabed block;

[0012] Step B2: Based on the soil parameters obtained in Step B1, conduct a simulation test on the change of the vertical bearing capacity of the guide pipe under vibration conditions with time, and fit the functional relationship between the coefficient of restitution of the vertical bearing capacity of the guide pipe with time under different vibration frequencies and vibration times.

[0013] Step B3: Obtain the construction parameters for the actual working conditions of the guide pipe in the seabed block, and calculate the total buoyancy W of the guide pipe and the delivery system. Load ;

[0014] Step B4: Based on the catheter resting time calculation model, obtain the continuous function t of catheter resting time under different vibration frequencies P and vibration times T under actual working conditions. min (T,P), and calculate the function t to shorten the duct static time under different vibration parameters. de (T,P);

[0015] Step B5: Obtain the function t, which determines the degree of reduction in catheter resting time, based on the gradient descent method. de The maximum value of (T,P) and the corresponding vibration time and vibration frequency.

[0016] Soil parameters include the undrained shear strength of clay, unit weight, and buoyancy coefficient of seawater, which vary with different depths of the seabed.

[0017] Construction parameters include the weight of the delivery tool, the weight of the guide pipe, the weight of the jetting drill assembly, the weight of the low-pressure wellhead, the diameter of the guide pipe, and the depth of the guide pipe run-in.

[0018] Step B2 specifically includes the following sub-steps:

[0019] Step B21: Based on the soil parameters of a specific seabed block, configure remolded soil with the same parameters;

[0020] Step B22: Place the diameter D t The simulated test showed that the duct was injected to a depth of L. t Simulation tests were conducted to study the change in vertical bearing capacity of the conduit with the time t of conduit removal under different vibration times T and vibration frequencies P.

[0021] Step B23: Obtain the vertical bearing capacity F of the duct under different vibration times T and vibration frequencies P in the simulation test in step B22. t The discrete points that vary with the catheter removal time t are fitted with vibration time T, vibration frequency P and catheter removal time t as independent variables. The functional relationship between the vertical bearing capacity of the catheter and time under different vibration times T and vibration frequencies P is as follows.

[0022] F t (t,T,P)=w(T,P)ln(t+y(T,P))+z(T,P) (1)

[0023] In the formula, F t The vertical bearing capacity of the catheter is simulated in kN; t is the catheter removal time in h; with T and P as constants, w, y, and z are constants and dimensionless.

[0024] Step B24: Calculate the vertical bearing capacity f per unit area of ​​the duct under different vibration times T and vibration frequencies P. u The functional relationship that changes with time is as follows:

[0025] f u (t,T,P)=F(t,T,P) / (D t πL t (2)

[0026] In the formula, f u Vertical bearing capacity per unit area of ​​the conduit, kN / m 2 ;D t To simulate the diameter of the test catheter, m; L t To simulate the insertion depth of the test catheter, m;

[0027] Step B25: Calculate the insertion depth L of the simulated test guide pipe under the soil parameters of the specific seabed block. t Vertical ultimate bearing capacity per unit area f umax (L t );

[0028] Step B26: The function for calculating the vertical bearing capacity recovery coefficient of the conduit as a function of time under different vibration frequencies P and vibration times T is as follows;

[0029]

[0030] In the formula, f is the vertical bearing capacity recovery coefficient of the conduit, which is dimensionless; when T and P are constant values, a and b are constants, which are dimensionless.

[0031] The calculation model for catheter resting time is as follows:

[0032] F a (t,T,P)=D a πf(t,T,P)f umax (L a )≥W load (4)

[0033] In the formula, f(t,T,P) is a function of the vertical bearing capacity restitution coefficient as a function of time under different vibration frequencies P and vibration times T. umax (L a The depth L of the guide pipe is determined by the soil parameters of the specific seabed block. a Vertical ultimate bearing capacity per unit area, WLoad The total buoyant weight of the conduit and the delivery system under actual working conditions, D a F represents the diameter of the conduit under actual working conditions. a (t,T,P) represents the vertical bearing capacity of the conduit under actual working conditions.

[0034] continuous function of catheter resting time t min The formula for calculating (T,P) is as follows:

[0035]

[0036] Function t to shorten catheter resting time de The formula for calculating (T,P) is as follows:

[0037]

[0038] In the formula, t min (0,0) represents the static time of the conduit under non-vibration conditions, in hours.

[0039] Step B5 specifically includes the following sub-steps:

[0040] Step B51: Select the initial value column vector x 0 =[T 0 ,P 0 ] T Given k = 0 and precision ε; then proceed to step B52;

[0041] Step B52: Calculate the column vector x in the k-th iteration. k =[T k ,P k ] T gradient of the objective function and gradient magnitude Proceed to step B53;

[0042] Step B53: Determine the gradient magnitude Is the precision less than or equal to ε? If yes, output x. k t de (x k If not, proceed to step B56; otherwise, proceed to step B54.

[0043] Step B54: Take Calculate the optimal step size α k To satisfy

[0044] t de (x k +α k S k ) = maxt de (xk +α k S k ) = maxt de (α); Proceed to step B55;

[0045] Step B55: Output x k+1 =x k +ɑ k S k k = k + 1, then proceed to step B52;

[0046] Step B56: Output t de (x k )=t de (T k ,P k ) is a function t de The maximum value of (T,P), i.e. the optimal resting time of the catheter, x k =[T k ,P k This refers to the vibration parameters corresponding to the optimal static time of the catheter.

[0047] The beneficial effects of this invention are as follows:

[0048] This invention can determine the optimal static time of the guide pipe and its corresponding optimal vibration time and vibration frequency under actual working conditions through low-cost indoor simulation tests based on different seabed soil parameters and guide pipe lowering construction parameters. In addition, it can be applied to actual working conditions to shorten the static time of the guide pipe, thereby shortening the installation time of the guide pipe under jetting and improving the installation speed. Attached Figure Description

[0049] Figure 1 This is a flowchart of a method for constructing a post-spraying vibration-stabilized conduit according to the present invention;

[0050] Figure 2 This is a schematic diagram of the catheter insertion system;

[0051] Figure 3 This is a schematic diagram of the jet insertion conduit;

[0052] Figure 4 This is a schematic diagram of the vibration-stabilized conduit after spraying;

[0053] Figure 5 This is a schematic diagram of the force exerted on the catheter when it is stationary;

[0054] Figure 6 This is a schematic diagram of the jet drilling tool-vibration device recovery process;

[0055] Figure 7 This is a flowchart of the overall method for calculating and optimizing the optimal static time of the duct under post-jet vibration conditions;

[0056] Figure 8 This is a flowchart of the simulation test and data processing of the vertical bearing capacity of the conduit changing over time;

[0057] Figure 9 The undrained shear strength S u Relationship diagram with depth L of seafloor rock strata;

[0058] Figure 10 This is a graph showing the relationship between unit weight γ and depth L of seafloor rock strata;

[0059] Figure 11 This is a flowchart for calculating the total buoyant weight of the catheter and the delivery system;

[0060] Figure 12 This is the calculation process for the settling time of the catheter under actual working conditions;

[0061] Figure 13 This is a flowchart for solving the optimal settling time of a catheter based on the gradient descent method.

[0062] Figure 14 This is a graph showing the calculation results of the reduction in the optimal resting time of the catheter;

[0063] Figure 15 This is a graph showing the calculated results of the catheter resting time;

[0064] In the diagram: 1-Conduit insertion tool, 2-Low-pressure wellhead, 3-Jet drill string, 4-Drilling fluid, 5-Vibration device, 6-Conduit, 7-Rock cuttings, 8-Seawater, 9-Submarine mudline, 10-Submarine rock strata, 11-Vibration wave. Detailed Implementation

[0065] This invention proposes a method for constructing a vibration-stabilized conduit after spraying. The invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0066] Figure 1 This is a flowchart of a method for constructing a post-spraying vibration-stabilized conduit according to the present invention; Figure 2 This is a schematic diagram of the catheter insertion system; Figure 3 This is a schematic diagram of the jet insertion conduit; Figure 4 This is a schematic diagram of the vibration-stabilized conduit after spraying; Figure 5 This is a schematic diagram of the force exerted on the catheter when it is stationary; Figure 6 This is a schematic diagram of the jet drilling tool-vibration device recovery; the specific operation process is as follows:

[0067] Step A1: Assemble the guide pipe insertion tool 1, low-pressure wellhead 2, jetting drill string 3, vibratory device 5, and guide pipe 6;

[0068] Step A2: The jetting drill 3 jets drilling fluid 4, and at the same time the guide pipe 6 is lowered to the target depth through seawater 8, seabed mudline 9, and seabed rock layer 10 in sequence. Rock cuttings 7 are generated around the jetting drill 3.

[0069] Step A3: Start the vibration device 5, adjust it to the optimal static time and corresponding vibration frequency of the guide pipe, and drive the guide pipe 6 to vibrate, so as to spread the vibration wave 11 to the surrounding soil to consolidate it and improve the vertical bearing capacity of the guide pipe 6.

[0070] Step A4: Turn off the vibration device 5 and let the conduit 6 stand still until its vertical bearing capacity and the total buoyancy of the system are in static balance;

[0071] Step A5: Release the feeding system, lift up the jetting drill 3, vibration device 5 and guide tube feeding tool 1 and retrieve them.

[0072] Figure 7 This is a flowchart outlining the overall process for calculating and optimizing the optimal static time of the guide pipe under vibration conditions after spraying. The process includes: obtaining soil parameters for a specific seabed block; conducting simulation tests based on these soil parameters to assess the change in the vertical bearing capacity of the guide pipe over time under vibration conditions and fitting the relationship between the coefficient of restitution of the vertical bearing capacity of the guide pipe and time at different vibration frequencies and times; obtaining the construction parameters for the actual guide pipe placement under the seabed block conditions; and calculating the total buoyant weight W of the guide pipe and the delivery system. Load Based on the hydrostatic equilibrium equation of the catheter, the continuous function t of the catheter resting time under different vibration frequencies P and vibration times T under actual working conditions is calculated. min (T,P) and calculate the function t that determines the reduction in the required static time of the duct under different vibration parameters. de (T,P); The function t is obtained by solving the gradient descent method. de The maximum value of (T,P) and the corresponding vibration time and vibration frequency; applied to actual working conditions, thereby shortening the installation time of the injection duct;

[0073] Figure 8 This is a flowchart of the simulation test and data processing of the vertical bearing capacity of the conduit changing over time; Figure 9 The undrained shear strength S u Relationship diagram with depth L of seafloor rock strata; Figure 10 This is a graph showing the relationship between unit weight γ and seafloor rock depth L; specifically, it includes obtaining soil parameters for a specific seafloor block, including the undrained shear strength of clay Su(L1), unit weight γ(L1), and the buoyancy coefficient B of seawater as varying with different seafloor depths L. fw Based on soil parameters at different depths L1, the undrained shear strength value Su(L1) and unit weight γ(L1) of clay were configured with remolded soil having the same parameters; a diameter of D was used. t The simulated test showed that the duct was injected to a depth of L. tSimulation tests were conducted to study the variation of the vertical bearing capacity of the conduit with static time t (t = 12h, 24h, 36h, 48h, 60h, 72h, 84h, 96h) under vibration times of 30min, 35min, 40min, 45min, and 50min and vibration frequencies of 5Hz, 15Hz, 20Hz, 25Hz, and 30Hz. The simulation tests yielded the vertical bearing capacity F of the conduit under different vibration times T and vibration frequencies P. t The discrete points that vary with the catheter removal time t are fitted with vibration time T, vibration frequency P and catheter removal time t as independent variables to obtain the functional relationship of the vertical bearing capacity of the catheter with time under different vibration time T and vibration frequency P (T, P and t are continuous values), as shown in equation (1).

[0074] F t (t,T,P)=w(T,P)ln(t+y(T,P))+z(T,P) (1)

[0075] In the formula, F t The vertical bearing capacity of the catheter is simulated in kN; t is the catheter removal time in h; with T and P as constants, w, y, and z are constants and dimensionless.

[0076] Calculate the vertical bearing capacity f per unit area of ​​the duct under different vibration times T and vibration frequencies P in the simulation test. u The functional relationship that changes with time is shown in equation (2);

[0077] f u (t, T, P) = F(t, T, P) / (D t πL t (2)

[0078] In the formula, f u Vertical bearing capacity per unit area of ​​the conduit, kN / m 2 ;D t To simulate the diameter of the test catheter, m; L t To simulate the insertion depth of the test catheter, m;

[0079] The simulation test was conducted with the guide pipe inserted to a depth of L under the parameters of the undrained shear strength of clay, Su(L1), and the unit weight γ(L1). t Vertical ultimate bearing capacity per unit area f umax (Lt), as shown in equations (3) to (5);

[0080] Calculate the ultimate vertical bearing capacity per unit area of ​​the guide pipe at different soil and rock depths:

[0081] f s (L)=αS u (L) (3)

[0082] In the formula, f s The ultimate vertical bearing capacity per unit area of ​​the guide pipe at different soil and rock depths, in kN / m. 2 α is the adhesion coefficient, α≤1; Su is the undrained shear strength, Pa;

[0083] According to API RP 2A standard (2000 edition), the adhesion coefficient α is determined as follows:

[0084]

[0085] In the formula: σ v For effective overburden compressive stress, Pa;

[0086] Calculate the effective overburden compressive stress σ when the soil depth is L. v :

[0087] σ v =γ(L)*L

[0088] Calculate the insertion of the catheter to L t Vertical ultimate bearing capacity per unit area f umax (L t ):

[0089]

[0090] The function of the vertical bearing capacity recovery coefficient of the conduit changing with time under different vibration frequencies P and vibration time T is calculated, as shown in (6);

[0091]

[0092] In the formula, f is the vertical bearing capacity recovery coefficient of the conduit, which is dimensionless; when T and P are constants, a and b are constants, which are dimensionless.

[0093] Figure 11 This is a flowchart for calculating the total buoyancy of the guide pipe and the delivery system, including obtaining the construction parameters for lowering the guide pipe into the seabed block, specifically including the weight W of the delivery tool. tooL Catheter weight W con Weight of jet drilling assembly (W) coL Low-pressure wellhead weight W Lh , catheter diameter D a With the depth of catheter insertion L a Based on the buoyancy coefficient B of seawater fw Tool weight W tooL Catheter weight W con Weight of jet drilling assembly (W) coL Weight W of low-pressure wellhead Lh Calculate the total buoyant weight W of the catheter and delivery system.Load As shown in equation (7);

[0094] W load =B fw (W con +W col +W lh +W tool (7)

[0095] Figure 12 This is the calculation process for the static time of the guide pipe under actual working conditions. It is based on the principle of static equilibrium of the guide pipe and the function f(t, T, P) of the vertical bearing capacity recovery coefficient of the guide pipe changing with time under different vibration frequencies P and vibration times T. The guide pipe is lowered to a depth L under the soil parameters of a specific seabed block. a Vertical ultimate bearing capacity per unit area f umax (L a Total buoyancy W of catheter and delivery system Load , catheter diameter D a With the depth of catheter insertion L a A calculation model for the static time of the catheter under actual working conditions is established, as shown in equations (8) to (9);

[0096] The calculated insertion depth of the guide pipe is L under the specific soil parameters of the seabed block. a Vertical ultimate bearing capacity per unit area f umax (L a ):

[0097]

[0098] Establish a calculation model for catheter settling time under actual working conditions:

[0099] F a (t, T, P) = D a πf(t, T, P)f umax (L a )≥W load (8)

[0100] In the formula, F a D represents the vertical bearing capacity of the conduit under actual working conditions, in kN. a The actual conduit diameter under actual working conditions is in meters (m); L a The actual insertion depth of the guide tube under working conditions, in meters (m).

[0101] The required settling time for the catheter under different vibration frequencies P and vibration times T can be calculated as a function t. min (T, P);

[0102]

[0103] The reduction in required settling time for the catheter under different vibration frequencies P and vibration times T is a function of t. de (T, P), as shown in equation (10);

[0104]

[0105] In the formula: t min (0,0) represents the static time of the conduit under non-vibration conditions, in hours;

[0106] Figure 13 This is a flowchart for solving the optimal settling time of a catheter based on the gradient descent method, specifically including:

[0107] Step B51: Select the initial value column vector x 0 =[0,0] T Given k = 0 and precision ε; then proceed to step B52;

[0108] Step B52: Calculate the column vector x in the k-th iteration. k =[T k P k ] T gradient of the objective function and gradient magnitude Proceed to step B53;

[0109] Step B53: Determine the gradient magnitude Is the precision less than or equal to ε? If yes, output x. k t de (x k If not, proceed to step B56; otherwise, proceed to step B54.

[0110] Step B54: Take Calculate the optimal step size a k To satisfy

[0111] t de (x k +α k S k ) = maxt de (x k +α k S k ) = maxt de (α); then proceed to step B55;

[0112] Step B55: Output x k+1 =x k +a k S k k = k + 1, then proceed to step B52;

[0113] Step B56: Output t de (x k )=t de (T k ,P k ) is a function t de The maximum value of (T,P), i.e. the optimal settling time for catheter insertion, x k =[T k ,P k This refers to the vibration parameters corresponding to the optimal resting time.

[0114] In summary, for a certain seabed environment, the specific implementation method of vibratory conduit construction after jetting and the calculation results of the optimal settling time for the conduit are as follows:

[0115] Step 1: Take soil samples from a specific seabed block and measure the soil parameters of the seabed soil. Prepare remolded soil with the same soil parameters as described above and conduct a simulation test on the change of the vertical bearing capacity of the guide pipe over time.

[0116] Step 2: Fit the function F of the vertical bearing capacity of the duct as a function of time under different vibration times T and vibration frequencies P based on the experimental results. t (t,T,P) and the function f(t,T,P) for the vertical bearing capacity restitution coefficient as a function of time;

[0117] Step 3: Obtain the construction parameters for the seabed block guide pipe installation and calculate the total buoyancy W of the guide pipe and the delivery system. Load ;

[0118] Step 4: Combine the function f(t,T,P) of the vertical bearing capacity recovery coefficient of the catheter with the total buoyant weight W of the catheter and the delivery system. Load Establish a calculation model for catheter static time under actual working conditions;

[0119] Step 5: Calculate the required settling time of the catheter under different vibration times T and vibration frequencies P, and fit a function t to the required settling time of the catheter under different vibration frequencies P and vibration times T. min (T,P), a function t that calculates the reduction in required catheter resting time for different vibration frequencies P and vibration times T. de (T,P);

[0120] Step 6: Solve for the function t using the gradient descent method. de The maximum value t of (T,P) de (T k ,P k ) and the corresponding vibration time and vibration frequency [T k ,P k ];

[0121] Step 7: Assemble the guide pipe insertion tool, jetting drill string, low-pressure wellhead, vibratory device and guide pipe; jetting drilling fluid from the drill string; lower the guide pipe to the target depth.

[0122] Step 8: Start the vibration device and adjust the vibration frequency and vibration time to the values ​​specified in Step 6 [T]. k ,P k After vibration is complete, turn off the vibration device;

[0123] Step 9: The shortest time for catheter stasis is t in step 6. de (T k ,P k The corresponding settling time, i.e. the optimal settling time when the vertical bearing capacity of the conduit can maintain static balance with the total buoyancy of the system;

[0124] Step 10: Release the guide tube insertion device, lift up the jetting drill, vibrating device, and guide tube insertion tool, and retrieve them.

[0125] Figure 14 The graph shows the calculated results of the reduction in catheter resting time; the reduction in the minimum required resting time of the catheter first increases and then decreases with the vibration frequency, and first increases and then decreases with the vibration time.

[0126] Figure 15 The graph shows the calculation results of the optimal settling time for the catheter. When the vibration parameters are [T,P]=[42.32,14.73], the reduction in the minimum settling time of the catheter is the greatest, at 89.2%.

[0127] This invention can determine the optimal static time of the guide pipe and its corresponding optimal vibration time and vibration frequency under actual working conditions through low-cost indoor simulation tests based on different seabed soil parameters and guide pipe lowering construction parameters. In addition, it can be applied to actual working conditions to shorten the static time of the guide pipe, thereby shortening the installation time of the guide pipe under jetting and improving the installation speed.

Claims

1. A method for constructing a vibration-stabilized guide tube after spraying, characterized in that, Includes the following steps: Step A1: Assemble the guide pipe insertion tool (1), low-pressure wellhead (2), jetting drill string (3), vibration device (5) and guide pipe (6); Step A2: The jetting drill (3) jets drilling fluid (4), and at the same time, the guide pipe (6) is lowered to the target depth through the seawater (8), the seabed mudline (9), and the seabed rock layer (10) in sequence. Rock cuttings (7) are generated around the jetting drill (3). Step A3: Start the vibration device (5), adjust it to the optimal static time of the guide pipe and the corresponding vibration frequency and vibration time, and drive the guide pipe (6) to vibrate, so as to spread the vibration wave (11) to the surrounding soil to consolidate it and improve the vertical bearing capacity of the guide pipe (6); the calculation method of the optimal static time of the guide pipe is as follows: Step B1: Obtain the soil parameters for the specific seabed block; Step B2: Based on the soil parameters obtained in Step B1, conduct a simulation test on the change of the vertical bearing capacity of the guide pipe under vibration conditions with time, and fit the functional relationship between the coefficient of restitution of the vertical bearing capacity of the guide pipe with time under different vibration frequencies and vibration times. Step B2 specifically includes the following sub-steps: Step B21: Based on the soil parameters of a specific seabed block, configure remolded soil with the same parameters; Step B22: [The following appears to be a separate, unrelated section:] ...with diameter D... t The simulated test showed that the depth of the ejected conduit was L. t Simulation tests were conducted to study the change in vertical bearing capacity of the conduit with the time t of conduit removal under different vibration times T and vibration frequencies P. Step B23: Obtain the vertical bearing capacity F of the duct under different vibration times T and vibration frequencies P in the simulation test in step B22. t The discrete points that vary with the catheter removal time t are fitted with vibration time T, vibration frequency P and catheter removal time t as independent variables. The functional relationship between the vertical bearing capacity of the catheter and time under different vibration times T and vibration frequencies P is as follows. （1） In the formula, F t The vertical bearing capacity of the catheter is simulated in kN; t is the catheter removal time in h; with T and P as constants, w, y, and z are constants and dimensionless. Step B24: Calculate the vertical bearing capacity f per unit area of ​​the duct under different vibration times T and vibration frequencies P. u The functional relationship that changes with time is as follows: （2） In the formula, f u Vertical bearing capacity per unit area of ​​the conduit, kN / m 2 ; D t To simulate the diameter of the test catheter, m; L t To simulate the insertion depth of the test catheter, m; Step B25: Calculate the insertion depth L of the simulated test guide pipe under the soil parameters of the specific seabed block. t Vertical ultimate bearing capacity per unit area f umax (L t ); Step B26: The function for calculating the vertical bearing capacity recovery coefficient of the conduit as a function of time under different vibration frequencies P and vibration times T is as follows; （3） In the formula, f is the vertical bearing capacity recovery coefficient of the conduit, which is dimensionless; When T and P are constants, a and b are constants and dimensionless. Step B3: Obtain the construction parameters for the actual working conditions of the guide pipe in the seabed block, and calculate the total buoyancy W of the guide pipe and the delivery system. Load ; Step B4: Based on the catheter resting time calculation model, obtain the continuous function t of catheter resting time under different vibration frequencies P and vibration times T under actual working conditions. min (T,P), and calculate the function t to shorten the duct static time under different vibration parameters. de (T,P); Step B5: Obtain the function t, which determines the degree of reduction in catheter resting time, based on the gradient descent method. de The maximum value of (T,P) and the corresponding vibration time and vibration frequency; Step A4: Turn off the vibration device (5) and let the conduit (6) stand still until its vertical bearing capacity and the total buoyancy of the system are in static balance; Step A5: Release the feed system, lift up the jetting drill (3), the vibration device (5) and the guide tube feed tool (1) and retrieve them.

2. The method for constructing a vibration-stabilized guide tube after spraying according to claim 1, characterized in that, Soil parameters include the undrained shear strength of clay, unit weight, and buoyancy coefficient of seawater, which vary with different depths of the seabed.

3. The method for constructing a vibration-stabilized guide tube after spraying according to claim 1, characterized in that, Construction parameters include the weight of the delivery tool, the weight of the guide pipe, the weight of the jetting drill assembly, the weight of the low-pressure wellhead, the diameter of the guide pipe, and the depth of the guide pipe run-in.

4. The method for constructing a post-jetting vibration-stabilized conduit according to claim 1, characterized in that, The calculation model for catheter resting time is as follows: （4） In the formula, f(t,T,P) is a function of the vertical bearing capacity restitution coefficient as a function of time under different vibration frequencies P and vibration times T. umax (L a The depth L of the guide pipe is determined by the soil parameters of the specific seabed block. a Vertical ultimate bearing capacity per unit area, W Load The total buoyant weight of the conduit and the delivery system under actual working conditions, D a This refers to the diameter of the conduit under actual working conditions. This represents the vertical bearing capacity of the conduit under actual working conditions.

5. The method for constructing a post-jetting vibration-stabilized conduit according to claim 4, characterized in that, continuous function of catheter resting time t min The formula for calculating (T,P) is as follows: （5）。 6. The method for constructing a vibration-stabilized guide tube after spraying according to claim 5, characterized in that, Function t to shorten catheter resting time de The formula for calculating (T,P) is as follows: （6） In the formula, t min (0,0) represents the static time of the conduit under non-vibration conditions, in hours.

7. The method for constructing a post-jetting vibration-stabilized conduit according to claim 1, characterized in that, Step B5 specifically includes the following sub-steps: Step B51: Select the initial value column vector x 0 =[T 0 ,P 0 ] T Given k=0 and precision ε; then proceed to step B52; Step B52: Calculate the column vector x in the k-th iteration. k =[T k ,P k ] T Gradient of objective function ▽t de (x k ) and gradient magnitude |▽t de (x k )│; Proceed to step B53; Step B53: Determine the gradient magnitude |▽t de (x k ) | Is it less than or equal to the precision ε? If yes, output x. k t de (x k If not, proceed to step B56; otherwise, proceed to step B54. Step B54: Take S k =-▽t de (x k ) / │▽t de (x k )│, calculate the optimal step size ɑ k To satisfy ； Proceed to step B55; Step B55: Output x k+1 =x k +ɑ k S k ,k=k+1, then go to step B52; Step B56: Output t de (x k )=t de (T k ,P k ) is a function t de The maximum value of (T,P), i.e. the optimal resting time of the catheter, x k =[T k ,P k This refers to the vibration parameters corresponding to the optimal static time of the catheter.

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