Shear evaluation method and device for ram blowout preventer for drill rod movement

Abstract

The invention discloses a ram blowout preventer shearing evaluation method and device for drill rod movement, and relates to the technical field of petroleum equipment detection and evaluation. The displacement shear test device comprises a base, a rack, a middle cross beam, a movable workbench, an upper sliding block, a lower sliding block, an upper oil cylinder and a lower oil cylinder, the upper oil cylinder and the lower oil cylinder drive the upper sliding block and the lower sliding block to slide in the vertical direction of the rack, and a drill rod in the ram preventer is driven to move to carry out a ram preventer moving shear test. According to the invention, under the condition of simulating on-site drill rod movement, the ram blowout preventer can shear the drill rod, the dynamic shearing capability of the ram blowout preventer can be evaluated, and support is provided for verifying and improving the shearing capability of a shearing ram. According to the flashboard shearing evaluation method for drill rod movement, the state of the flashboard shearing drill rod can be effectively evaluated, parameter changes in the flashboard shearing process can be dynamically analyzed, the product quality of the shearing flashboard can be evaluated in a targeted mode, and data support is provided for design verification of the shearing flashboard.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum equipment detection and evaluation, and more specifically to a method and device for shear evaluation of a gate blowout preventer for drill pipe movement. Background Art

[0002] With the exploitation of deep and ultra-deep oil and gas wells, the operating conditions are extremely harsh, and it is crucial to equip high-quality well control devices. As the last safety barrier for well control, the gate blowout preventer must have the ability to shear the drill pipe, seal the wellhead, and suppress the blowout in case of emergency situations such as blowouts and well surges, otherwise it is easy to cause serious blowout accidents. According to the API 16A standard, the tests to verify the shear capacity of the gate blowout preventer are static shear under basic conditions such as eccentric shear and sealed shear. However, at the drilling site, shearing is often carried out under very urgent and complex conditions, and the shearing capacity of the gate blowout preventer is severely tested. Among them, the situation where the drill pipe moves upward with the blowout is even more dangerous, which is a great test for the shearing performance and sealing performance of the gate of the gate blowout preventer. Therefore, the evaluation and improvement of the shearing capacity of the gate blowout preventer with drill pipe movement is of great engineering significance to reducing the risk of blowout accidents.

[0003] At present, the shear gate test is a commonly used inspection and evaluation method for the performance of gate blowout preventers. Shear sealing test, shear diameter design range test, eccentric shear test and lateral force shear test are carried out to verify the shear capacity and sealing capacity of the gate of the gate blowout preventer. Generally, the shear test of the gate blowout preventer is carried out according to API 16A and GB / T20174-2019 "Drilling Equipment for Petroleum and Natural Gas Drilling and Production Equipment", which stipulates the pressure and time of the shear sealing test; the drill pipe diameter, pressure and time required for the shear diameter design range test; the drill pipe position, pressure and time of the eccentric shear test; the drill pipe load, pressure and time of the lateral force shear test and other steps and requirements.

[0004] The existing technical standards mainly simulate shear tests under static conditions such as sealing and eccentricity. The test steps are simple and relatively single compared with the complex working conditions on site. It is impossible to verify whether the gate blowout preventer can withstand mechanical properties, impact properties, etc. under multiple working conditions. The verification of the shear capacity of the gate blowout preventer has certain limitations and does not have the verification and evaluation capabilities to simulate complex working conditions at the drilling site. Summary of the invention

[0005] In order to overcome the defects in the above-mentioned prior art, the present invention discloses a gate blowout preventer shear evaluation method and device for drill pipe movement. The present invention proposes that during the drill pipe movement, the gate blowout preventer shears the drill pipe and dynamically evaluates the shear capacity of the gate, thereby ensuring that the gate blowout preventer can quickly shear the drill pipe under actual movement conditions and achieve rapid well shut-in.

[0006] In order to achieve the above objectives, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for evaluating shear of a ram blowout preventer for drill pipe movement, comprising the following steps:

[0008] In the present invention, the movement of the gate shearing the drill pipe is divided into three stages. The first stage: before the gate contacts the drill pipe; the second stage: the gate just contacts the drill pipe and the drill pipe is clamped by the gate and stops moving upward; the third stage: the gate shears after the drill pipe stops moving upward. Assuming that the real-time shear force of the gate is f, the diameter of the drill pipe is D, during the drill pipe shearing process, when the gate movement time is t, the hydraulic control oil pressure of the gate blowout preventer control device is p t .

[0009] 1. Before the gate and drill pipe come into contact

[0010] S1. Open the shear gate of the gate blowout preventer. The shear gate starts to move. The average moving speed of the gate is v c1 After running for Δt, the shear test device is started again, and the average moving speed of the drill pipe is v d1 After t1 time, the cutting edge of the shear gate contacts the outer wall of the drill pipe. At this time, the distance the drill pipe moves upward is h1, and the distance the shear gate moves horizontally is s1;

[0011] Preferably, before the gate contacts the drill pipe in step S1, the hydraulic control oil pressure of the gate blowout preventer control device is p t Does not change with time, according to p t The time variation curve of the time can be obtained at time Δt+t1;

[0012] h1=v d1 ×t1;

[0013] s1=v c1 ×(Δt+t1).

[0014] 2. As soon as the gate and the drill pipe come into contact, the drill pipe is clamped by the gate and stops moving upward.

[0015] S2. The shear ram continues to move after the cutting edge of the shear ram contacts the outer wall of the drill pipe. The average moving speed of the shear ram is v. c2 After t2 time, the drill pipe stops moving. The average moving speed of the drill pipe during this process is v d2 In this process, the distance that the drill pipe moves upward is h2, and the distance that the shear gate moves in the horizontal direction is s2;

[0016] Preferably, in the process of the gate plate and the drill pipe just coming into contact and the drill pipe being clamped by the gate plate to stop upward movement in step S2, the hydraulic control oil pressure of the gate plate blowout preventer control device is p tIncrease rapidly over time;

[0017] h2=v d2 ×t2;

[0018] s2=v c2 ×t2.

[0019] Preferably, in the steps S1 and S2, the total distance that the drill rod moves upward during the shearing process is h;

[0020] h=h 1+ h2;

[0021] The height between the lower slider and the middle beam of the shear test device is H, and h and H satisfy the following relationship:

[0022] h<H.

[0023] 3. The gate shears after the drill pipe stops moving upward.

[0024] S3, the drill pipe stops moving, and the shear gate continues to shear to the specified position. The average moving speed of the shear gate in this process is v c3 The movement time is t3, the distance of horizontal shear gate movement is s3, and the hydraulic pressure of the gate blowout preventer control device during this process is p t ;

[0025] Preferably, in the process of the gate shearing movement after the drill pipe stops rising in step S3, the hydraulic control oil pressure of the gate blowout preventer control device is p t Increase rapidly over time;

[0026] s3=v c3 ×t3;

[0027] The drill pipe diameter D is:

[0028] D=s2+s3.

[0029] 4. Drill pipe shearing judgment

[0030] S4. Utilize the distances s1, s2 and s3 of the horizontal shear gate movement to obtain the gate movement distance, and determine whether the drill pipe can be sheared when it moves based on the comparison between the gate movement distance and the maximum gate stroke, as well as the hydraulic control oil pressure of the gate blowout preventer control device.

[0031] In the above steps, the gate movement distance is the sum of s1, s2 and s3.

[0032] Preferably, in the step S4, judging whether the drill rod can be cut when it moves includes: assisting in judging whether the drill rod can be cut when it moves according to the oil pressure required when the distance moved by both sides of the gate plate reaches a specified position;

[0033] When the diameter of the drill pipe is D, the initial velocity of the drill pipe is v d1 When the shear force that can successfully cut the drill pipe is f D , f D =p t ×A0; where p t is the hydraulic control oil pressure of the gate blowout preventer control device, and A0 is the effective area of ​​the contact surface of the gate blowout preventer cylinder.

[0034] Preferably, in the step S4, judging whether the drill rod can be cut when it moves includes: the moving distances of the left and right sides of the gate are x1 and x2, and the maximum stroke of the single-side gate is x0. By comparing the moving distance of the gate with the maximum stroke of the gate, it is judged whether the moving drill rod can be cut smoothly.

[0035] Preferably, in step S4, judging whether the drill rod can be cut when it moves includes: when x1≥x0, x2≥x0, and f≥ε×f D When , f is the real-time shear force of the gate, ε is the shear force correction coefficient, and the drill rod can be sheared smoothly; otherwise, the drill rod cannot be sheared smoothly.

[0036] In a second aspect, the present invention provides a shear test device for evaluating the shear of a gate blowout preventer with drill pipe movement, comprising a base, a frame, an intermediate beam, a movable workbench, an upper slide block, a lower slide block, an upper oil cylinder and a lower oil cylinder;

[0037] The frame is mounted on the base, the middle crossbeam is mounted in the middle of the frame, the mobile workbench is mounted on the middle crossbeam, a gate blowout preventer is mounted on the mobile workbench, and a drill pipe is mounted in the gate blowout preventer;

[0038] The upper slider and the lower slider are both slidably assembled on the frame and are respectively located above and below the movable workbench. The upper oil cylinder and the lower oil cylinder drive the upper slider and the lower slider to slide in the vertical direction of the frame, driving the drill pipe in the gate blowout preventer to move to perform a gate blowout preventer movement shear test.

[0039] Preferably, the lower oil cylinder passes through the middle cross beam, and its piston rod includes a lower piston rod big end at the upper part and a lower piston rod small end at the lower part, and the lower piston rod big end and the lower piston rod small end are respectively connected to the upper slider and the lower slider.

[0040] Preferably, the small end of the lower piston rod is mounted on the connecting head of the lower slider through a latch.

[0041] Preferably, the middle crossbeam is provided with a through center hole for installing a drill pipe, and the size of the center hole is consistent with the size of the main diameter hole of the gate blowout preventer; the mobile workbench is equipped with a mobile guide rail, and the gate blowout preventer is installed on the mobile workbench by bolts.

[0042] In the present invention, the middle crossbeam is penetrated by a center hole to facilitate the up and down movement of the drill pipe, and the size of the center hole is consistent with the size of the main diameter hole of the gate blowout preventer. The mobile workbench is installed on the middle crossbeam and is equipped with a mobile guide rail to facilitate the moving of the mobile workbench, the installation of the gate blowout preventer and the hoisting of the drill pipe. The gate blowout preventer is fixed to the mobile workbench by bolt connection.

[0043] Preferably, the lower slider is provided with a first slide rail in the vertical direction, the top end of which is connected to the small end of the lower piston rod, and the bottom end of the drill rod is installed on the lower slider; when the lower cylinder pushes the piston rod of the lower cylinder at a set speed, the small end of the lower piston rod drives the lower slider to move upward along the first slide rail, pushing the drill rod upward.

[0044] In the present invention, the lower slider is provided with four slide rails in the vertical direction, and the middle of both sides is connected to the small head of the lower piston rod by hinges. The drill rod is connected to the lower slider by bolts. When the lower cylinder pushes the piston rod of the lower cylinder at a set speed, the small head of the lower piston rod drives the lower slider to move upward along the slide rails, thereby pushing the drill rod upward.

[0045] Preferably, the upper slider is provided with a second slide rail in the vertical direction, the bottom end of which is connected to the big end of the lower piston rod, and the upper oil cylinder is provided with a plurality of upper piston rods, the upper oil cylinder being connected to the top end of the upper slider;

[0046] When the drill rod is connected to the upper slider, the upper oil cylinder drives the upper slider to move downward to the drill rod connection position, and uses a steel wire rope to flexibly connect the drill rod to the upper slider;

[0047] During the upward movement of the drill rod, the upper oil cylinder is closed, and the lower oil cylinder drives the lower slider to move upward synchronously with the upper slider, driving the drill rod to move.

[0048] In the present invention, the upper slider is provided with four slide rails in the vertical direction, and the two sides are connected to the big end of the lower piston rod by hinges, and are connected to the two upper piston rods of the upper cylinder at the upper end of the upper slider. When the drill rod is connected to the upper slider, the upper cylinder provides power to move the upper slider down to the drill rod connection, and the drill rod is flexibly connected to the upper slider by a steel wire rope to prevent the drill rod from falling after being cut. During the upward movement of the drill rod, the upper cylinder is closed, and the lower cylinder provides power to push the lower slider and the upper slider to move upward synchronously, driving the drill rod to move.

[0049] Preferably, an upper end connecting piece is installed at the top end of the drill rod through a connecting pin, a lifting lug is arranged at the top end of the upper end connecting piece, and the steel wire rope is arranged on the lifting lug.

[0050] In a third aspect, based on the above-mentioned shear test device, the present invention also provides a test method of a shear test device for evaluating the shear of a gate blowout preventer with drill pipe movement, comprising the following steps:

[0051] Step 1, hoisting of drill pipe: move out the mobile workbench, install the gate blowout preventer on the mobile workbench, then transfer the drill pipe connected at the upper end into the gate blowout preventer, and use the upper end connector on the drill pipe to hang the drill pipe on the upper end face of the gate blowout preventer;

[0052] Step 2, connection between drill rod and lower slider: After the drill rod is hoisted, move the mobile workbench to the center of the frame, and the upper oil cylinder drives the upper slider to move downward to a suitable position, and connect the connector of the lower slider to the small end of the lower piston rod through a latch; then the lower oil cylinder drives the lower slider upward, so that the drill rod is inserted into the drill rod connecting sleeve of the lower slider;

[0053] Step 3: Connect the top of the drill rod to the upper slider: After the drill rod is connected to the lower slider, use a wire rope to connect the lifting lug at the upper end of the drill rod to the lower end connector of the upper slider;

[0054] Step 4: Drill pipe movement shearing process: first close the shear gate of the gate blowout preventer, then start the movement shear test button. After the test device is started, the lower slider drives the drill pipe to move upward, and the upper slider also moves upward, and shearing is carried out during the movement of the drill pipe;

[0055] Step 5: Disassembly of drill pipe after shearing: first take the cut upper part of the drill pipe, move the lower slider downward so that the cut lower part of the drill pipe is under the mobile workbench, hang the cut upper part of the drill pipe on the gate blowout preventer, move out of the mobile workbench, and hang out the cut upper part of the drill pipe;

[0056] After taking out the cut upper half of the drill rod, move it into the mobile workbench, move the lower slider upward so that the cut lower half of the drill rod is exposed on the upper surface of the mobile workbench, install the drill rod clamp so that the cut lower half of the drill rod sits on the mobile workbench, move out of the mobile workbench, and lift out the cut lower half of the drill rod through the lifting lug on the drill rod clamp.

[0057] Beneficial effects of the present invention:

[0058] The present invention can simulate the on-site drill pipe movement condition, where the gate blowout preventer shears the drill pipe, and realizes the dynamic shear capacity evaluation of the gate blowout preventer, providing support for verifying and improving the shear capacity of the shear gate. The drill pipe movement speed of the device is adjustable, and it has a stepless speed regulation function. During the shearing process, the test device will continue to maintain the force, which can better simulate the actual situation of the on-site drill pipe movement. Among them, the gate shear evaluation method for drill pipe movement can effectively evaluate the state of the gate shearing the drill pipe, dynamically analyze the parameter changes of the gate shearing process, and can evaluate the product quality of the shear gate in a targeted manner, providing data support for the design verification of the shear gate. The present invention realizes gate shear evaluation for the moving drill pipe, breaking through the problem that only static shearing of the drill pipe can be achieved at home and abroad, and provides a test basis for drafting domestic and foreign drill pipe movement shear evaluation standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a general assembly effect diagram of the oscillating shear test device of the present invention;

[0060] Figure 2 This is a rendering of the other side of the overall assembly of the oscillating shear test device of the present invention;

[0061] Figure 3 The mobile workbench of the present invention is moved out of the diagram;

[0062] Figure 4 This is a diagram showing the upper end connection of a drill rod according to the present invention;

[0063] Figure 5 This is a drill rod suspension diagram of the present invention;

[0064] Figure 6 This is a diagram showing the connection between the small end of the lower piston rod and the lower slider of the present invention;

[0065] Figure 7 It is a cross-sectional view of the lower piston cylinder of the present invention;

[0066] Figure numerals: 1—upper cylinder, 2—upper piston rod, 3—upper slider, 4—big end of lower piston rod, 5—drill rod, 6—lower cylinder, 7—gate blowout preventer, 8—movable workbench, 9—middle crossbeam, 10—small end of lower piston rod, 11—lower slider, 12—base, 13—frame, 14—movable guide rail, 15—pin, 16—connecting head, 17—lifting ear, 18—upper end connecting piece, 19—connecting pin. DETAILED DESCRIPTION

[0067] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings to fully understand the purpose, characteristics and effects of the present invention.

[0068] Example 1

[0069] A shear test device for evaluating the shear of a gate blowout preventer with drill pipe movement, such as Figure 1-7 As shown, it includes a base 12, a frame 13, an intermediate beam 9, a movable workbench 8, an upper slider 3, a lower slider 11, an upper cylinder 1 and a lower cylinder 6;

[0070] The frame 13 is mounted on the base 12, the middle crossbeam 9 is mounted in the middle of the frame 13, the mobile workbench 8 is mounted on the middle crossbeam 9, a gate blowout preventer 7 is mounted on the mobile workbench 8, and a drill pipe 5 is mounted in the gate blowout preventer 7;

[0071] The upper slider 3 and the lower slider 11 are both slidably assembled on the frame 13 and are respectively located above and below the movable workbench 8. The upper oil cylinder 1 and the lower oil cylinder 6 drive the upper slider 3 and the lower slider 11 to slide in the vertical direction of the frame 13, driving the drill pipe 5 in the gate blowout preventer 7 to move to perform a shear test of the gate blowout preventer 7.

[0072] like Figure 1 and 7 As shown, the lower oil cylinder 6 passes through the middle cross beam 9, and its piston rod includes a lower piston rod big head 4 at the upper part and a lower piston rod small head 10 at the lower part. The lower piston rod big head 4 and the lower piston rod small head 10 are respectively connected to the upper slider 3 and the lower slider 11.

[0073] like Figure 6 As shown, the lower piston rod small end 10 is installed on the connecting head 16 of the lower slider 11 through a latch 15.

[0074] The middle crossbeam 9 is provided with a through center hole for mounting the drill pipe 5, and the size of the center hole is consistent with the size of the main diameter hole of the gate blowout preventer 7; the mobile workbench 8 is equipped with a mobile guide rail 14, and the gate blowout preventer 7 is mounted on the mobile workbench 8 by bolts.

[0075] In this embodiment, the middle crossbeam 9 is penetrated by a center hole to facilitate the up and down movement of the drill pipe 5, and the size of the center hole is consistent with the size of the main diameter hole of the gate blowout preventer 7. The mobile workbench 8 is installed on the middle crossbeam 9 and is equipped with a mobile guide rail 14 to facilitate the moving of the mobile workbench 8, the installation of the gate blowout preventer 7 and the hoisting of the drill pipe 5. The gate blowout preventer 7 is fixed to the mobile workbench 8 by bolt connection.

[0076] The lower slider 11 is provided with a first slide rail in the vertical direction, the top end of which is connected to the small end 10 of the lower piston rod, and the bottom end of the drill rod 5 is installed on the lower slider 11; when the lower cylinder 6 pushes the piston rod of the lower cylinder 6 at a set speed, the small end 10 of the lower piston rod drives the lower slider 11 to move upward along the first slide rail, pushing the drill rod 5 upward.

[0077] In this embodiment, the lower slider 11 is provided with four slide rails in the vertical direction, and is connected to the lower piston rod small head 10 by hinges in the middle of both sides. The drill rod 5 is connected to the lower slider 11 by bolts. When the lower cylinder 6 pushes the piston rod of the lower cylinder 6 at a set speed, the lower piston rod small head 10 drives the lower slider 11 to move upward along the slide rails, thereby pushing the drill rod 5 upward.

[0078] The upper slider 3 is provided with a second slide rail in the vertical direction, the bottom end of which is connected to the big end 4 of the lower piston rod, and the upper cylinder 1 is provided with a plurality of upper piston rods 2 of the upper cylinder 1, which are connected to the top end of the upper slider 3;

[0079] When the drill rod 5 is connected to the upper slider 3, the upper oil cylinder 1 drives the upper slider 3 to move downward to the connection position of the drill rod 5, and uses a steel wire rope to flexibly connect the drill rod 5 to the upper slider 3;

[0080] During the upward movement of the drill rod 5 , the upper oil cylinder 1 is closed, and the lower oil cylinder 6 drives the lower slider 11 to move upward synchronously with the upper slider 3 , thereby driving the drill rod 5 to move.

[0081] In this embodiment, the upper slider 3 is provided with four slide rails in the vertical direction, and the two sides are connected to the big end 4 of the lower piston rod by hinges, and are connected to the two upper piston rods 2 of the upper cylinder 1 at the upper end of the upper slider 3. When the drill rod 5 is connected to the upper slider 3, the upper cylinder 1 provides power, so that the upper slider 3 moves down to the connection of the drill rod 5, and the drill rod 5 is flexibly connected to the upper slider 3 by a wire rope to prevent the drill rod 5 from falling after being cut. During the upward movement of the drill rod 5, the upper cylinder 1 is closed, and the lower cylinder 6 provides power to push the lower slider 11 to move upward synchronously with the upper slider 3, driving the drill rod 5 to move.

[0082] like Figure 4 As shown, an upper end connector 18 is installed at the top of the drill rod 5 through a connecting pin 19 , and a lifting lug 17 is provided at the top of the upper end connector 18 , and the steel wire rope is provided on the lifting lug 17 .

[0083] Example 2

[0084] The present invention proposes that during the movement of the drill pipe, the gate blowout preventer shears the drill pipe and dynamically evaluates the shearing capacity of the gate, thereby ensuring that the gate blowout preventer can quickly shear the drill pipe under actual movement conditions and quickly shut in the well. To achieve the above purpose, the specific implementation cases of the present invention are as follows:

[0085] The overall assembly effect diagram of the shear test device is as follows: Figure 1 As shown, the specific implementation steps of the test shear are as follows:

[0086] Step 1: hoisting of drill pipe. Figure 3 As shown, the mobile workbench 8 is moved out, and the blowout preventer 7 is installed on the mobile workbench 8, and then Figure 4The drill pipe 5 connected at the upper end of the drill pipe is transferred into the blowout preventer 7, and the drill pipe is hung on the upper end surface of the blowout preventer 7 by using the upper end connecting piece 18 on the drill pipe 5, as shown in FIG. Figure 5 shown.

[0087] Step 2: Connect the drill rod to the lower slider. After completing the hoisting of the drill rod in step 1, move the mobile workbench 8 to the center of the stand, and the upper cylinder 1 drives the upper slider 3 to move downward to a suitable position, such as Figure 6 As shown, the connector 16 of the lower slider 11 is connected to the lower piston rod small end 10 by a latch 15. Afterwards, the lower oil cylinder 6 drives the lower slider 11 upward, so that the drill rod 5 is inserted into the lower slider drill rod connecting sleeve.

[0088] Step 3, connection between the top of the drill rod and the upper slider. After completing step 2, connection between the drill rod and the lower slider, use a wire rope to connect the lifting hole at the upper end of the drill rod 5 to the lower end connector of the upper slider 3.

[0089] Step 4, drill pipe shearing process. First close the shear gate of the blowout preventer 7, then start the shearing test button. After the test device is started, the lower slider 11 drives the drill pipe 5 to move upward, and the upper slider 3 also moves upward, and shearing is performed during the movement of the drill pipe 5.

[0090] Step 5, disassembly of the drill pipe after shearing. First take the cut upper half of the drill pipe, move the lower slider 11 so that the cut lower half of the drill pipe is below the mobile workbench 8, hang the cut upper half of the drill pipe on the blowout preventer 7, move out the mobile workbench 8, and lift out the cut upper half of the drill pipe. After taking out the cut upper half of the drill pipe, move into the mobile workbench 8, move the lower slider 11 upward, so that the cut lower half of the drill pipe is exposed on the upper surface of the mobile workbench 8, install the drill pipe clamp, so that the cut lower half of the drill pipe sits on the mobile workbench, move out the mobile workbench 8, and lift out the cut lower half of the drill pipe through the lifting lug on the drill pipe clamp.

[0091] Example 3

[0092] The evaluation method of the gate shearing of the drill pipe movement is as follows, and the gate shearing drill pipe movement is divided into three stages. The first stage: before the gate contacts the drill pipe; the second stage: the gate just contacts the drill pipe and the drill pipe is clamped by the gate to stop moving upward; the third stage: the gate shearing movement after the drill pipe stops moving upward. Assume that the real-time shear force of the gate is f, the diameter of the drill pipe is D, and during the drill pipe shearing process, when the gate movement time is t, the hydraulic control oil pressure of the blowout preventer control device is p t .

[0093] (1) In the first stage, the solenoid valve closing button of the BOP shear gate is turned on, and the average moving speed of the gate is v c1After running for Δt, the shearing device is started again, and the average moving speed of the drill pipe is v d1 After t1 time, the cutting edge of the shear gate contacts the outer wall of the drill pipe. At this time, the distance the drill pipe moves upward is h1, and the distance the shear gate moves horizontally is s1. In this process, the hydraulic pressure of the BOP control device is p t Does not change with time, according to p t The time variation curve of can obtain the time Δt+t1.

[0094] h1=v d1 ×t1;

[0095] s1=v c1 ×(Δt+t1).

[0096] (2) In the second stage, the cutting edge of the shear gate just contacts the outer wall of the drill pipe, and the average moving speed of the gate is v c2 After t2 time, the drill pipe stops moving. The average moving speed of the drill pipe during this process is v d2 In this process, the distance that the drill pipe moves upward is h2, and the distance that the shear gate moves horizontally is s2. In this process, the hydraulic pressure of the control device is p t Increases rapidly over time.

[0097] h2=v d2 ×t2;

[0098] s2=v c2 ×t2;

[0099] The total distance the drill pipe moves upward during shearing is h.

[0100] h=h 1+ h2;

[0101] The height between the lower slider and the middle beam is H. To prevent the lower slider from colliding with the middle beam during the upward movement of the drill rod, the following relationship should be met:

[0102] h<H;

[0103] (3) In the third stage, the drill pipe stops moving and the gate continues to shear. The average moving speed of the gate during this process is v c3 The distance that the shear gate moves in the horizontal direction is s3. In this process, the hydraulic pressure of the control device is p t Increases rapidly over time.

[0104] s3=v c3 ×t3;

[0105] in,

[0106] D = s2 + s3;

[0107] (4) According to the oil pressure required when the gate moves to the specified position, it is used to assist in judging whether the drill pipe can be cut when it moves. Through a large number of simulation analyses, it is found that when the drill pipe diameter is D, the initial velocity on the drill pipe is v d1 When the shear force that can successfully cut the drill pipe is f D Through monitoring, it is known that the hydraulic pressure of the control device is p t , the effective area A0 of the cylinder contact surface.

[0108] f D =p t ×A0;

[0109] (5) During the drill pipe shearing process, the gate moves on the left and right sides by x1 and x2, and the maximum stroke of the gate on one side is x0. By comparing the gate movement distance and the maximum stroke of the gate, it can also be judged whether the moving drill pipe is successfully sheared.

[0110] Combining the judgment conditions (4) and (5), it is possible to reliably make an accurate evaluation of the shearing capacity of the shear gate. D When ε is the shear force correction coefficient, the drill pipe can be cut smoothly. Otherwise, the drill pipe cannot be cut smoothly.

[0111] The above is a specific description of the implementation mode of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A method for evaluating shear of a ram blowout preventer for drill pipe movement, characterized in that: The following steps are involved: S1. Open the shear gate of the gate blowout preventer. The shear gate starts to move. The average moving speed of the gate is v c1 After running for Δt, the shear test device is started again, and the average moving speed of the drill pipe is v d1 After t1 time, the cutting edge of the shear gate contacts the outer wall of the drill pipe. At this time, the distance the drill pipe moves upward is h1, and the distance the shear gate moves horizontally is s1; S2. The shear ram continues to move after the cutting edge of the shear ram contacts the outer wall of the drill pipe. The average moving speed of the shear ram is v. c2 After t2 time, the drill pipe stops moving. The average moving speed of the drill pipe during this process is v d2 In this process, the distance that the drill pipe moves upward is h2, and the distance that the shear gate moves in the horizontal direction is s2; S3, the drill pipe stops moving, and the shear gate continues to shear to the specified position. The average moving speed of the shear gate in this process is v c3 The movement time is t3, the distance of horizontal shear gate movement is s3, and the hydraulic pressure of the gate blowout preventer control device during this process is p t ; S4. Utilize the distances s1, s2 and s3 of the horizontal shear gate movement to obtain the gate movement distance, and determine whether the drill pipe can be sheared when it moves based on the comparison between the gate movement distance and the maximum gate stroke, as well as the hydraulic control oil pressure of the gate blowout preventer control device.

2. The ram blowout preventer shear evaluation method according to claim 1, characterized in that: In step S1, before the gate contacts the drill pipe, the hydraulic control oil pressure of the gate blowout preventer control device is p t Does not change with time, according to p t The time variation curve of the time Δt+t1 can be obtained; h1=v d1 ×t1; s1=v c1 ×(Δt+t1).

3. The ram blowout preventer shear evaluation method according to claim 1, characterized in that: In step S2, when the gate and the drill pipe just come into contact and the drill pipe is clamped by the gate and stops rising, the hydraulic pressure of the gate blowout preventer control device is p t Increase rapidly over time; h2=v d2 ×t2; s2=v c2 ×t2。 4. The ram blowout preventer shear evaluation method according to claim 1, characterized in that: In the steps S1 and S2, the total distance that the drill pipe moves upward during the shearing process is h; h=h 1+ h2; The height between the lower slider and the middle beam of the shear test device is H, and h and H satisfy the following relationship: h<H.

5. The ram blowout preventer shear evaluation method according to claim 1, characterized in that: In the process of the gate shearing movement after the drill pipe stops moving upward in step S3, the hydraulic control oil pressure of the gate blowout preventer control device is p t Increase rapidly over time; s3=v c3 ×t3; The drill pipe diameter D is: D=s2+s3.

6. The ram blowout preventer shear evaluation method according to claim 1, characterized in that: In the step S4, judging whether the drill rod can be cut when it moves includes: according to the oil pressure required when the distance between the two sides of the gate plate moves to reach the specified position, auxiliary judging whether the drill rod can be cut when it moves; When the diameter of the drill pipe is D, the initial velocity of the drill pipe is v d1 When the shear force that can successfully cut the drill pipe is f D , f D =p t ×A0; where p t is the hydraulic control oil pressure of the gate blowout preventer control device, and A0 is the effective area of ​​the contact surface of the gate blowout preventer cylinder.

7. The ram blowout preventer shear evaluation method according to claim 6, characterized in that: In the step S4, judging whether the drill rod can be cut when it moves includes: the moving distances of the left and right sides of the gate are x1 and x2, and the maximum stroke of the single-side gate is x0. By comparing the moving distance of the gate with the maximum stroke of the gate, it is judged whether the moving drill rod is successfully cut.

8. The ram blowout preventer shear evaluation method according to claim 7, characterized in that: In the step S4, judging whether the drill rod can be cut when it moves includes: when x1≥x0, x2≥x0, and f≥ε×f D When , f is the real-time shear force of the gate, ε is the shear force correction coefficient, and the drill rod can be sheared smoothly; otherwise, the drill rod cannot be sheared smoothly.

9. A shear test device for evaluating the shear of a gate blowout preventer with drill pipe movement, characterized in that: It includes a base, a frame, a middle crossbeam, a movable workbench, an upper slide block, a lower slide block, an upper oil cylinder and a lower oil cylinder; The frame is mounted on the base, the middle crossbeam is mounted in the middle of the frame, the mobile workbench is mounted on the middle crossbeam, a gate blowout preventer is mounted on the mobile workbench, and a drill pipe is mounted in the gate blowout preventer; The upper slider and the lower slider are both slidably assembled on the frame and are respectively located above and below the movable workbench. The upper oil cylinder and the lower oil cylinder drive the upper slider and the lower slider to slide in the vertical direction of the frame, driving the drill pipe in the gate blowout preventer to move to perform a gate blowout preventer movement shear test.

10. The oscillating shear test device according to claim 9, characterized in that: The lower oil cylinder passes through the middle cross beam, and its piston rod comprises a lower piston rod big end at the upper part and a lower piston rod small end at the lower part. The lower piston rod big end and the lower piston rod small end are connected to the upper slider and the lower slider respectively.

11. The oscillating shear test device according to claim 9, characterized in that: The middle crossbeam is provided with a through center hole for installing a drill pipe, and the size of the center hole is consistent with the size of the main diameter hole of the gate blowout preventer; the mobile workbench is equipped with a mobile guide rail, and the gate blowout preventer is installed on the mobile workbench by bolts.

12. The oscillating shear test device according to claim 10, characterized in that: The lower slider is provided with a first slide rail in the vertical direction, the top end of which is connected to the small end of the lower piston rod, and the bottom end of the drill rod is installed on the lower slider; when the lower oil cylinder pushes the piston rod of the lower oil cylinder at a set speed, the small end of the lower piston rod drives the lower slider to move upward along the first slide rail, pushing the drill rod upward.

13. The oscillating shear test device according to claim 10, characterized in that: The upper slider is provided with a second slide rail in the vertical direction, the bottom end of which is connected to the big end of the lower piston rod, and the upper oil cylinder is provided with a plurality of upper piston rods, the upper oil cylinder being connected to the top end of the upper slider; When the drill rod is connected to the upper slider, the upper oil cylinder drives the upper slider to move downward to the drill rod connection position, and uses a steel wire rope to flexibly connect the drill rod to the upper slider; During the upward movement of the drill rod, the upper oil cylinder is closed, and the lower oil cylinder drives the lower slider to move upward synchronously with the upper slider, driving the drill rod to move.

14. The oscillating shear test device according to claim 13, characterized in that: An upper end connecting piece is installed at the top end of the drill rod through a connecting pin, a lifting lug is arranged at the top end of the upper end connecting piece, and the steel wire rope is arranged on the lifting lug.

15. The oscillating shear test device according to claim 10, characterized in that: The small end of the lower piston rod is installed on the connecting head of the lower sliding block through a latch.

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