CN117948044B - A six-degree-of-freedom wave compensation offshore drilling platform and its working method - Google Patents

Abstract

The invention discloses a six-degree-of-freedom wave-compensated offshore drilling platform and a wave compensation method thereof, wherein the platform comprises a floating hull, a wave compensation device and a lifting device; the wave compensation device adjusts the pose of the drill machine and controls the drilling work of the drill bit, and the lifting device further increases the drilling depth of the drill bit; the upper surface of the lifting device is provided with a drilling machine, and a drill rod connected with the drilling machine stretches into the floating vessel body for drilling work; a limiter connected to the lower surface of the lifting device controls the drill rod to keep vertical in drilling work; the inertial navigation system monitors the position, speed and azimuth data of the floating hull; and after processing the data measured by the inertial navigation system, the master control platform controls the movement of each part based on the calculation result. The invention can effectively compensate six-degree-of-freedom wave interference movements such as side movement, longitudinal movement, heave, pitching, rolling, yawing and the like of the waves, and limit the position of a drill rod, thereby ensuring the stable drilling of a drill bit at the bottom of a well in the offshore oil drilling and production process.

Description

A six-degree-of-freedom wave compensation offshore drilling platform and its working method

Technical Field

The invention relates to deep-sea equipment, and in particular to an offshore drilling platform with six degrees of freedom wave compensation and a working method thereof.

Background Art

With the increasing demand for resources such as oil and natural gas in various countries around the world, oil and gas resource exploration has expanded from land to sea to cope with the shortage of land oil and gas resources, and the difficulty of exploration has become increasingly greater. During offshore oil drilling and production operations, due to the interference of marine environments such as wind, waves, and currents, the drilling equipment will produce periodic fluctuations, causing the drill bit to be unable to stably fit the bottom of the well for drilling, affecting the quality of drilling operations, and even causing various safety accidents in serious cases, threatening the lives and health of workers. Therefore, in order to cope with the impact of wave interference on offshore oil drilling and production work and ensure the stability and reliability of drilling platform operations, it is necessary to provide an offshore oil drilling platform with wave compensation function so that the drill bit can stably contact the bottom of the well.

The prior art with publication number CN103939033A discloses a hydraulic wave compensation device for an offshore drilling rig, including a drilling tower, a tower top pulley, a wire rope, and a hydraulic wave compensation device. The drill bit is kept at the same height in a wave environment by charging and discharging pressurized gas at the upper end of an accumulator in the hydraulic wave compensation device.

The prior art with publication number CN105253264B discloses a wave compensation device for a deepwater semi-submersible drilling platform, including three rigid columns distributed in an equilateral triangle shape, which compensates for the roll, pitch and heave motion of the main deck of the upper platform by controlling the movement of the three rigid columns.

The above invention does not have the comprehensive compensation for the six-degree-of-freedom interference motion of the waves, and no corresponding drill rod limiting mechanism is set. The drill rod may be skewed during the movement, affecting the quality of the drilling operation.

Summary of the invention

The purpose of the present invention is to provide an offshore drilling platform with six-degree-of-freedom wave compensation and a working method thereof, which can effectively compensate for the lateral displacement, longitudinal displacement, heave and six-degree-of-freedom wave interference movements such as pitch, roll and yaw of the waves, and can further increase the drilling depth of the drill bit, thereby ensuring the stable drilling of the drill bit at the bottom of the well during offshore oil drilling and production, can reduce the number of operations for connecting single roots, shorten the oil drilling and production cycle, and effectively improve the comprehensive performance of the system.

Technical solution: A six-degree-of-freedom wave-compensated offshore drilling platform of the present invention comprises a floating hull, a wave-compensating device installed above the floating hull via a drilling tower, and a lifting device connected below the wave-compensating device;

The wave compensation device is used to adjust the position of the drilling rig and control the drilling work of the drill bit, and the lifting device is used to further increase the drilling depth of the drill bit;

A drilling rig is installed on the upper surface of the lifting device, and a drill rod is connected to the output shaft of the drilling rig. The drill rod passes through the lifting plate of the lifting device and extends into the floating hull for drilling work;

A limiter is installed on the lower surface of the lifting device, and the limiter is used to control the drill rod to remain vertical during drilling;

The floating hull is installed with an inertial navigation system and a master control platform. The inertial navigation system is used to monitor the position, speed and azimuth data of the floating hull. The master control platform is connected with the inertial navigation system, the wave compensation device, the lifting device, the drilling rig and the limiter. After the master control platform processes the data measured by the inertial navigation system, the movement of each part is controlled based on the calculation results.

Furthermore, two sets of limiters are installed symmetrically on the lower surface of the lifting device. The limiters include rollers, the grooves of the rollers are facing the drill rod, and the rollers are installed on the transmission assembly. The transmission assembly pushes the rollers toward the drill rod under the action of the driving assembly until they are pressed against the drill rod, so that the drill rod remains vertical during drilling.

Furthermore, the driving assembly includes a driving motor, and the transmission assembly includes a lead screw and an X-shaped slide; the driving motor is connected to the lead screw through a coupling, and two bottom legs of the X-shaped slide are respectively hinged to the sliding shaft and the fixed shaft, and the sliding shaft and the lead screw are connected through a nut seat, so that the rotation of the lead screw is converted into the longitudinal movement of the sliding shaft;

When the sliding shaft moves downward, it pushes the X-shaped slide to extend toward the center, and when the sliding shaft moves upward, it pushes the X-shaped slide to retract.

Furthermore, the limiter includes a limiter control box, on which a slide groove for installing the sliding shaft is longitudinally opened, and a positioning hole for installing the fixed shaft is opened below the slide groove;

A horizontal support plate and a vertical support plate are fixedly installed inside the limiter control box, wherein a slide groove and a positioning hole are opened on the vertical support plate, which are coaxial with the slide groove and the positioning hole on the limiter control box and are smaller than the same axis.

Furthermore, a push plate is installed on the two top legs of the X-shaped slide, a slide groove for installing another sliding shaft is longitudinally opened on the push plate, a positioning hole for installing another fixed shaft is opened below the slide groove, and the two top legs of the X-shaped slide are respectively hingedly connected to the other sliding shaft and the other fixed shaft;

The drive motor of the limiter is started, and the drive motor transmits the rotation to the lead screw through the coupling. The lead screw and the nut seat are matched with each other to convert the rotation of the lead screw into the translational motion of the nut seat. The sliding shaft follows the nut seat to translate up and down, pushing the X-shaped slide to extend and retract toward the center, thereby driving the translational motion of the push plate;

The push plate is fixedly connected with a roller mounting frame, and the roller mounting frame has two vertically arranged through holes at one end close to the drill rod for movably mounting the rolling shaft;

The rolling shaft passes through the center of the roller shaft end and is fixedly connected to the roller. The groove of the roller faces the drill rod. As the limiter drive motor rotates, the center of the roller gradually presses against or moves away from the drill rod. Through the cooperation of the two sets of limiters, the drill rod remains vertical during drilling.

Further, the wave compensation device includes a platform base, a compensation plate, six driving electric cylinders and corresponding driving servo motors;

The two ends of the driving electric cylinder are respectively hinged to the platform base and the compensation plate through Hooke's joints or ball joints, and the six hinge points are connected in sequence to form a regular hexagon, in which three groups of opposite sides are equal;

The driving electric cylinder is divided into an electric cylinder upper end and an electric cylinder lower end. The electric cylinder upper end is hinged to the bearing seat on the compensation plate through a Hook's joint or a ball joint, and the electric cylinder lower end is hinged to the bearing seat on the platform base through a Hook's joint or a ball joint.

Furthermore, the driving electric cylinder adopts a linear electric cylinder, and the driving servo motor is directly connected to the driving screw of the driving electric cylinder through a coupling.

Furthermore, the lifting device includes a base, a lifting plate, three electric cylinders and an electric control system;

The base is fixedly mounted on the compensation plate of the wave compensation device by bolts, and the three electric cylinders are distributed in an equilateral triangle and are all installed perpendicular to the base. The upper end of the electric cylinder is hinged to the bearing seat on the lifting plate by a Hook joint or a ball joint, and the lower end of the electric cylinder is connected to the base by a pin shaft;

A through hole is provided at the center of the lifting plate, and the through hole is aligned with the wellhead position on the floating hull, so that the drill rod can pass vertically;

The electric control system is connected to the electric cylinder and is used for driving and controlling the electric cylinder.

Furthermore, the drilling rig includes a driving motor, a coupling, a drilling rig support frame, and a limit sleeve; the driving motor is fixedly installed on the support plate of the drilling rig support frame, the output end of the driving motor is connected to the shaft end of the drill rod through the coupling, the drilling rig support frame includes support legs on both sides and a support plate fixedly connected to the top of the support legs, the center of the support plate is fixedly connected to the limit sleeve, the drill rod is divided into a threaded end and a screw hole end, and multiple drill rods are connected in sequence through the cooperation of the thread and the screw hole.

Based on the same inventive concept, the present invention also includes a working method of an offshore drilling platform with six degrees of freedom wave compensation, which is applied to the above-mentioned offshore oil drilling platform with six degrees of freedom wave compensation, and includes the following steps:

The inertial navigation system measures the real-time position, velocity and azimuth data of the floating hull;

The data processing module in the master control platform processes information and couples the position change of the floating hull with the displacement required by the drilling rig;

The coupling amount is converted into the coordinate change of the hinge point on the platform base in the wave compensation device by using coordinate transformation, and the real-time length of the driving electric cylinder in the wave compensation device is obtained according to the new coordinate of the hinge point on the platform base and the fixed coordinate of the hinge point on the compensation plate in the wave compensation device;

Calculate the difference between the real-time length of the driving electric cylinder and the length at the initial position to obtain the compensation amount of the driving electric cylinder;

The master control platform sends control instructions according to the compensation amount of the driving electric cylinder to control the driving electric cylinder to move;

Repeat the above steps to achieve real-time compensation for the wave interference motion.

Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

(1) It can realize comprehensive compensation for the lateral displacement, longitudinal displacement, heave, pitch, roll, yaw and other interfering motions of the waves during offshore oil drilling and production operations, so that the drill bit can drill stably at the bottom of the well, ensuring the stability and reliability of the drilling platform operation;

(2) The wave compensation device in the present invention is a six-degree-of-freedom wave compensation platform with small error, strong stability and strong bearing capacity, which is conducive to improving the overall performance of the offshore oil drilling platform. It can not only compensate for the six-degree-of-freedom interference motion of the waves, but also control the drilling and retraction operations of the drilling equipment; the heave device in the present invention further increases the drilling depth of the drill bit, reduces the steps of connecting a single root, and shortens the time of oil drilling;

(3) The present invention adopts a floating hull as a carrier of the drilling platform, which can be moved and reused after a resource exploration, thus avoiding waste of investment; the drilling rig structure in the present invention is equipped with a limiter, which can limit the position of the drill rod, so that it can remain vertical during drilling work and is not prone to skewing, thereby ensuring the quality of offshore oil drilling operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of an offshore drilling platform with six degrees of freedom wave compensation according to the present invention;

FIG2 is a schematic diagram of the structure of the wave compensation device in the present invention;

FIG3 is a schematic diagram of the structure of the heave device in the present invention;

FIG4 is a schematic diagram of the structure of the heave device in the present invention;

FIG5 is a schematic flow chart of a working method of an offshore drilling platform with six degrees of freedom wave compensation according to the present invention;

FIG6 is a diagram of position compensation error in the present invention;

FIG. 7 is a diagram of the posture compensation error in the present invention.

DETAILED DESCRIPTION

The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.

Example 1

As shown in FIG1 , the offshore drilling platform with six degrees of freedom wave compensation of the present invention comprises a floating hull 1, a master control platform 2, a drill rod 3, a stopper 4, a drilling rig 5, a wave compensation device 6, a lifting device 7, a drilling tower 8, an inertial navigation system 9, and a thruster 10. The floating hull 1 is a hollow steel structure, and four thrusters 10 are installed at its lower part, two of which are arranged in parallel at the bow and the stern to provide a power source. A wellhead is opened on the floating hull 1 so that the drill rod 3 can pass through the wellhead for drilling. The drilling tower 8 is a four-sided truss structure, which provides an installation environment for compensation equipment and drilling equipment, etc. Its lower base is fixedly installed on the deck of the floating hull 1, and the wave compensation device 6 is fixedly installed on the top mounting plate by bolts. The wave compensation device 6 is installed above the floating hull 1, and the lifting device 7 is connected below the wave compensation device 6. A drilling rig 5 is installed on the upper surface of the lifting device 7. The output shaft of the drilling rig 5 is connected to a drill rod 3. The drill rod 3 passes through the lifting plate 71 of the lifting device 7 and extends into the floating hull 1 through the wellhead for drilling. A limiter 4 is installed on the lower surface of the lifting device 7. The limiter 4 is used to control the drill rod 3 to remain vertical during drilling. An inertial navigation system 9 and a master control platform 2 are installed above the floating hull 1. The inertial navigation system 9 is used to monitor the position, speed, azimuth and other data of the floating hull 1; the master control platform 2 is connected to the inertial navigation system 9, the wave compensation device 6, the lifting device 7, the drilling rig 5, and the limiter 4. After the master control platform 2 processes the data measured by the inertial navigation system 9, it controls the movement of each part based on the calculation results.

The inertial navigation system 9 is used to monitor the position, speed, azimuth and other information of the floating body 1. The master control platform 2 includes a data processing module and a drive control module, wherein the data processing module processes the information obtained by the inertial navigation system 9, couples the position change of the floating body 1 with the displacement required by the drilling rig 5, and converts the coupling amount into the coordinate change of the hinge point on the platform base 63 in the wave compensation device 6 through coordinate transformation, obtains the real-time length of the six driving electric cylinders 65 according to the new coordinates of the hinge point on the platform base 63 and the fixed coordinates of each hinge point on the compensation plate 61, and obtains the compensation amount of the driving electric cylinder 65 according to the difference between the real-time length and the initial position length. The drive control module issues a control instruction according to the compensation amount, drives the electric cylinder to move, performs comprehensive compensation of the six-degree-of-freedom interference motion of the sea wave and motion control of the drilling work.

As shown in FIG2 , the wave compensation device 6 is a six-degree-of-freedom wave compensation platform, which is used to adjust the position of the drilling rig and control the drilling work of the drill bit, and includes a platform base 63, a compensation plate 61, six driving electric cylinders 65 and corresponding driving servo motors 62. The two ends of the driving electric cylinder 65 are respectively hinged to the platform base 63 and the compensation plate 61 through a Hooke's hinge or a ball hinge, and the six hinge points are connected in sequence to form a regular hexagon, in which three groups of opposite sides are equal, and the sum of the central angles corresponding to the closer hinge point and the farther hinge point is 120°, ensuring that the bearing capacity is evenly distributed. The driving electric cylinder 65 is divided into an electric cylinder upper end 652 and an electric cylinder lower end 651. The electric cylinder upper end 652 is hinged to the bearing seat 64 on the compensation plate 61 through a Hooke's hinge or a ball hinge, and the electric cylinder lower end 651 is hinged to the bearing seat 64 on the platform base 63 through a Hooke's hinge or a ball hinge.

In this embodiment, the driving electric cylinder 65 is a linear electric cylinder, and the driving servo motor 62 is directly connected to the driving screw of the driving electric cylinder 65 through a coupling, thereby improving the control accuracy.

As shown in FIG3 , the lifting device 7 is used to further increase the drilling depth of the drill bit, and includes a base 73, a lifting plate 71, three electric cylinders 74 and an electric control system. The base 73 is fixedly mounted on the compensation plate 61 of the wave compensation device 6 by bolts, and the three electric cylinders 74 are distributed in an equilateral triangle and are all installed perpendicular to the base 73 to ensure that the bearing capacity can be evenly distributed. The upper end 742 of the electric cylinder 74 is hinged to the bearing seat on the lifting plate 71 through a Hook hinge or a ball hinge, and the lower end 741 of the electric cylinder 74 is connected to the base 73 through a pin shaft. The electric control system is connected to the electric cylinder 74, and the electric control system controls each electric cylinder separately to realize the drive control of the electric cylinder 74. A through hole 72 is opened at the center of the lifting plate 71, and the through hole 72 is aligned with the wellhead position on the floating hull 1 up and down, so that the drill rod 3 can pass vertically.

As shown in Fig. 4, the drilling rig 5 includes a driving motor 53, a coupling 55, a drilling rig support frame 51, and a limiting sleeve 52. The driving motor 53 is fixedly mounted on a support plate of the drilling rig support frame 51, and an output end 54 of the driving motor 53 is connected to the shaft end of the drill rod 3 through a coupling 55. The drilling rig support frame 51 includes support legs on both sides and a support plate fixedly connected to the top of the support legs, and a limiting sleeve 52 is fixedly connected to the center of the support plate. The drill rod 3 is divided into a threaded end and a screw hole end, and multiple drill rods 3 are connected in sequence through the cooperation of the thread and the screw hole.

Two sets of stoppers 4 are installed symmetrically on the lower surface of the lifting device 7. The two sets of stoppers 4 work together to control the drill rod 3 to remain vertical during drilling. The stopper 4 includes a roller 44, the notch of the roller 44 faces the drill rod 3, and the roller 44 is installed on the transmission assembly. The transmission assembly pushes the roller 44 to move toward the drill rod 3 under the action of the driving assembly until it presses against the drill rod 3, so that the drill rod 3 remains vertical during drilling.

In this embodiment, the driving assembly includes a driving motor, and the transmission assembly includes a lead screw 41 and an X-shaped slide 48; the driving motor is connected to the lead screw 41 through a coupling, and the two bottom legs of the X-shaped slide 48 are respectively hinged to the sliding shaft 42 and the fixed shaft 46, and the sliding shaft 42 is connected to the lead screw 41 through a nut seat, so that the rotation of the lead screw 41 is converted into the longitudinal movement of the sliding shaft 42. When the sliding shaft 42 moves downward, it pushes the X-shaped slide 48 to extend toward the center, and when the sliding shaft 42 moves upward, it pushes the X-shaped slide 48 to retract.

In this embodiment, a slide groove 47 for installing the sliding shaft 42 is longitudinally provided on the limiter control box 43 of the limiter 4, and a positioning hole for installing the fixed shaft 46 is provided below the slide groove 47, so as to facilitate the installation and removal of the sliding shaft 42 and the fixed shaft 46. A transverse support plate and a vertical support plate are fixedly installed inside the limiter control box 43, wherein a slide groove 47 and a positioning hole are provided on the vertical support plate, which are coaxial with the slide groove 47 and the positioning hole on the limiter control box 43 and are smaller than the same period.

The two top legs of the X-shaped slide 48 are provided with a push plate 45, a slide groove 47 for installing another sliding shaft 42 is longitudinally opened on the push plate 45, and a positioning hole for installing another fixed shaft 46 is opened below the slide groove 47. The two top legs of the X-shaped slide 48 are respectively hingedly connected with the other sliding shaft 42 and the other fixed shaft 46. The driving motor of the limiter 4 transmits the rotation to the lead screw 41 through the coupling, and the lead screw 41 and the nut seat are screw-fitted to convert the rotation of the lead screw 41 into the translational motion of the nut seat, and the sliding shaft 42 follows the nut seat to translate up and down, pushing the X-shaped slide 48 to extend and retract toward the center, thereby driving the translational motion of the push plate.

The push plate 45 is fixedly connected with a roller mounting frame. The roller mounting frame has two vertically arranged through holes at one end close to the drill rod 3, which are used to movably mount a rolling shaft, so that the installed roller can roll. The shaft end of the rolling shaft is movably mounted on the through hole, and the center of the rolling shaft is fixed with the roller. The rolling shaft passes through the center of the shaft end of the roller 44 and is fixedly connected to the roller 44. The notch of the roller 44 faces the drill rod 3. As the stopper driving motor rotates, the center of the roller gradually presses against or moves away from the drill rod. Through the cooperation of the two sets of stoppers 4, the drill rod 3 is ensured to remain vertical during drilling.

The working process of the present invention is as follows: first, the displacement amount required for drilling by the drilling rig 5 is set to 0, the wave compensation device 6 is started, and the six electric cylinders 65 are driven according to the wave compensation method to realize real-time compensation for the interference movement of the sea waves; the driving motor of the limiter 4 is started, and the rotation of the motor is converted into the translational movement of the push plate 45 through the screw 41, and the position of the drill rod 3 is limited by two sets of rollers 44, so that it can only move and rotate axially and cannot deflect or tilt; when the drill bit needs to drill, the driving motor 53 of the drilling rig 5 is started, and the output end 54 of the driving motor 53 transmits the rotation to the drill rod 3 through the coupling 55, and in total The displacement amount required for drilling of the drilling rig 5 is input into the control platform 2. When the stroke of the driving electric cylinder 65 of the wave compensation device 6 reaches the limit, the drilling displacement amount no longer increases. At this time, the three driving electric cylinders 74 of the lifting device 7 are controlled to extend synchronously according to the drilling displacement amount, so as to further increase the drilling depth of the drilling rig 5. When the drill bit needs to be withdrawn, the three driving electric cylinders 74 of the lifting device 7 are controlled to shrink synchronously. When the driving electric cylinders 74 of the lifting device 7 are fully retracted and the drill bit still needs to be withdrawn, the displacement amount required for withdrawal of the drilling rig 5 is input into the main control platform 2 to realize the further withdrawal of the drill bit and efficiently complete the offshore oil drilling and production operation.

Example 2

As shown in FIG5 , a working method of an offshore drilling platform with six degrees of freedom wave compensation according to the present invention is applied to the above-mentioned offshore drilling platform with six degrees of freedom wave compensation, and comprises the following steps:

S1. The inertial navigation system 9 measures the real-time position, speed and azimuth data of the floating hull 1.

In this step, the inertial navigation system 9 installed on the deck of the floating hull 1 is used to measure the real-time position, speed, azimuth and other information of the floating hull 1 and send the data to the master control platform 2, wherein the coordinate system of the inertial navigation system 9 is u-xyz.

S2. The data processing module in the master control platform 2 performs information processing to couple the position change of the floating hull 1 with the displacement required for drilling by the drilling rig 5.

S3. Use coordinate transformation to convert the coupling amount into the coordinate change of the hinge point on the platform base 63 in the wave compensation device 6, and obtain the real-time length of the driving electric cylinder 65 in the wave compensation device 6 according to the new coordinates of the hinge point on the platform base 63 and the fixed coordinates of the hinge point on the compensation plate 61 in the wave compensation device 6.

In this step, the coordinate system of the platform base 63 is defined as w-xyz; the coordinate transformation method uses the inertial navigation system 9 to measure the movement of the floating body 1 and its offset compared to the coordinate system of the platform base 63, and obtains the new coordinates of the hinge point in the wave compensation device in the fixed coordinate system at each moment.

In this embodiment, the method for solving the real-time posture of the platform base 63 under the wave interference motion is: the Euler angle xyz type method is used to describe the posture of the platform base 63, and the initial position coordinate system w-xyz of the platform base is first rotated around the x-axis by α to reach the coordinate system w-xy'z', then rotated around the y' axis by β to reach the coordinate system w-x'y'z ₁ , and finally rotated around the z ₁ axis by γ to reach the coordinate system wx ₁ y ₁ z ₁ , and the final rotation transformation matrix is obtained. The expression of the rotation transformation matrix is:

S4. Calculate the difference between the real-time length of the driving electric cylinder 65 and the length at the initial position to obtain the compensation amount of the driving electric cylinder 65.

In this step, the length of the driving cylinder 65 of the platform base 63 under the wave interference motion is compared with the length at the initial position to obtain the length change Δl _i (i=1, 2, ... 6) required for the driving cylinder 65 when the platform base 63 moves from the initial position to the real-time position.

S5. The master control platform 2 sends a control instruction according to the compensation amount of the driving electric cylinder 65 to control the driving electric cylinder 65 to move.

In this step, the controller sends a control instruction to control the driving electric cylinder 65 to move according to the length change value of the driving electric cylinder 65, so that the position and posture of the compensation plate 61 remain constant, wherein the coordinate system of the compensation plate 61 is defined as v-xyz;

S6. Repeat the above steps to achieve real-time compensation for the wave interference movement and ensure stable contact between the drill bit and the bottom of the well.

As shown in Figure 6, under the six-degree-of-freedom interference motion of waves, the components of the center position coordinates of the compensation plate in the wave compensation device on the X-axis, Y-axis and Z-axis, that is, its lateral displacement, longitudinal displacement and heave, fluctuate only within 0.2 mm, and the fluctuation range is extremely small. The components of the center attitude coordinates of the compensation plate in the wave compensation device on the X-axis, Y-axis and Z-axis are shown in Figure 7, that is, its pitch, roll and yaw components all fluctuate within 0.005°, indicating that the compensation plate in the wave compensation device is basically in a static state, thereby verifying the effectiveness of the wave compensation method and ensuring the safety and efficiency of drilling operations.

Claims (7)

1. The utility model provides an offshore drilling platform of six degrees of freedom wave compensation which characterized in that: comprises a floating body (1), a wave compensation device (6) arranged above the floating body (1) through a drilling tower (8), and a lifting device (7) connected below the wave compensation device (6);

the wave compensation device (6) is used for adjusting the pose of the drilling machine and controlling the drilling work of the drill bit, and the lifting device (7) is used for further increasing the drilling depth of the drill bit;

the drilling machine (5) is mounted on the upper surface of the lifting device (7), the drill rod (3) is connected with the output shaft of the drilling machine (5), and the drill rod (3) penetrates through the lifting plate (71) of the lifting device (7) and stretches into the floating ship body (1) to be used for drilling;

a limiter (4) is arranged on the lower surface of the lifting device (7), and the limiter (4) is used for controlling the drill rod (3) to keep vertical in drilling work;

The floating body (1) is provided with an inertial navigation system (9) and a master control platform (2), and the inertial navigation system (9) is used for monitoring the position, the speed and the azimuth data of the floating body (1); the main control platform (2) is connected with the inertial navigation system (9), the wave compensation device (6), the lifting device (7), the drilling machine (5) and the limiter (4), and after the data measured by the inertial navigation system (9) are processed by the main control platform (2), the movement of each part is controlled based on a calculation result;

two groups of limiters (4) are symmetrically arranged on the lower surface of the lifting device (7) in a central mode, each limiter (4) comprises a roller (44), the notch of each roller (44) is opposite to the drill rod (3), each roller (44) is arranged on the corresponding transmission component, and the transmission component pushes the corresponding roller (44) to move towards the drill rod (3) under the action of the corresponding driving component until the corresponding roller presses against the drill rod (3), so that the drill rod (3) is kept vertical in drilling work;

the driving assembly comprises a driving motor, and the transmission assembly comprises a lead screw (41) and an X-shaped sliding frame (48); the driving motor is connected with the screw rod (41) through a coupler, two bottom supporting legs of the X-shaped sliding frame (48) are respectively hinged with the sliding shaft (42) and the fixed shaft (46), the sliding shaft (42) is connected with the screw rod (41) through a nut seat, and the rotation of the screw rod (41) is converted into the longitudinal movement of the sliding shaft (42);

the sliding shaft (42) pushes the X-shaped sliding frame (48) to extend towards the center when moving downwards, and the sliding shaft (42) pushes the X-shaped sliding frame (48) to retract when moving upwards;

The two top support legs of the X-shaped carriage (48) are provided with push plates (45), the push plates (45) are longitudinally provided with sliding grooves (47) for installing another sliding shaft (42), positioning holes for installing another fixed shaft (46) are formed below the sliding grooves (47), and the two top support legs of the X-shaped carriage (48) are respectively hinged with the other sliding shaft (42) and the other fixed shaft (46);

Starting a driving motor of the limiter (4), transmitting rotation to a screw rod (41) through a coupler, converting the rotation of the screw rod (41) into translational motion of a nut seat through spiral fit between the screw rod (41) and the nut seat, and enabling a sliding shaft (42) to translate up and down along with the nut seat to push an X-shaped sliding frame (48) to extend and retract towards the center so as to drive translational motion of a push plate;

the push plate (45) is fixedly connected with a roller mounting frame, and one end of the roller mounting frame, which is close to the drill rod (3), is provided with two vertically arranged through holes for movably mounting a rolling shaft;

The rolling shaft penetrates through the shaft end center of the roller (44) and is fixedly connected with the roller (44), the notch of the roller (44) is opposite to the drill rod (3), along with the rotation of the driving motor of the limiter (4), the center of the roller (44) is gradually pressed against or far away from the drill rod (3), and the drill rod (3) is kept vertical in drilling work through the cooperation of the two groups of limiters (4).

2. The six degree of freedom wave compensated offshore drilling platform of claim 1 wherein: the limiter (4) comprises a limiter control box (43), a sliding groove (47) for installing a sliding shaft (42) is longitudinally formed in the limiter control box, and a positioning hole for installing a fixed shaft (46) is formed below the sliding groove (47);

the inside of the limiter control box (43) is fixedly provided with a transverse supporting plate and a vertical supporting plate, wherein a sliding groove (47) and a positioning hole are formed in the vertical supporting plate, and the sliding groove is coaxial with the sliding groove (47) and the positioning hole on the limiter control box (43) and is reduced in the same ratio.

3. The six degree of freedom wave compensated offshore drilling platform of claim 1 wherein: the wave compensation device (6) comprises a platform base (63), a compensation plate (61), six driving electric cylinders (65) and corresponding driving servo motors (62);

Two ends of the driving electric cylinder (65) are respectively hinged with the platform base (63) and the compensation plate (61) through Hooke hinges or spherical hinges, and six hinge points are sequentially connected to form a regular hexagon, wherein three groups of opposite sides are respectively equal;

The driving electric cylinder (65) is divided into an electric cylinder upper end (652) and an electric cylinder lower end (651), the electric cylinder upper end (652) is hinged with a bearing seat (64) on the compensation plate through a hook joint or a spherical joint, and the electric cylinder lower end (651) is hinged with the bearing seat (64) on the platform base (63) through the hook joint or the spherical joint.

4. A six degree of freedom wave compensated offshore drilling platform according to claim 3, wherein: the driving electric cylinder (65) adopts a linear electric cylinder, and the driving servo motor (62) is directly connected with a transmission screw rod of the driving electric cylinder (65) through a coupler.

5. The six degree of freedom wave compensated offshore drilling platform of claim 1 wherein: the lifting device (7) comprises a base (73), a lifting plate (71), three electric cylinders (74) and an electric control system;

The base (73) is fixedly arranged on the compensation plate (61) of the wave compensation device (6) through bolts, three electric cylinders (74) are distributed in an equilateral triangle shape and are all arranged perpendicular to the base (73), the upper ends (742) of the electric cylinders (74) are hinged with bearing seats on the lifting plate (71) through Hooke hinges or spherical hinges, and the lower ends (741) of the electric cylinders (74) are connected with the base (73) through pin shafts;

a through hole (72) is formed in the center of the lifting plate (71), and the through hole (72) is aligned with a wellhead on the pontoon body (1) for a drill rod (3) to vertically pass through;

The electric control system is connected with the electric cylinder (74) and used for driving and controlling the electric cylinder (74).

6. The six degree of freedom wave compensated offshore drilling platform of claim 1 wherein: the drilling machine (5) comprises a driving motor (53), a coupler (55), a drilling machine support frame (51) and a limit sleeve (52);

the driving motor (53) is fixedly arranged on a supporting plate of the drilling machine supporting frame (51), an output end (54) of the driving motor (53) is connected with the shaft end of the drill rod (3) through a coupler (55), the drilling machine supporting frame (51) comprises supporting legs on two sides and a supporting plate fixedly connected with the tops of the supporting legs, a limiting sleeve (52) is fixedly connected to the center of the supporting plate, the drill rod (3) is divided into a threaded end and a threaded hole end, and a plurality of drill rods (3) are sequentially connected through the matching of threads and the threaded holes.

7. A method of operating a six degree of freedom wave compensated offshore drilling rig, the method being applied to the six degree of freedom wave compensated offshore drilling rig of claim 1, comprising the steps of:

The inertial navigation system (9) measures real-time position, speed and azimuth data of the floating hull (1);

The data processing module in the master control platform (2) processes information and couples the pose change quantity of the floating pontoon body (1) with the displacement quantity of the drilling machine (5) to be drilled;

converting the coupling amount into coordinate change of a hinge point on a platform base (63) in the wave compensation device (6) by utilizing coordinate transformation, and obtaining real-time length of a driving electric cylinder (65) in the wave compensation device (6) according to new coordinate of the hinge point on the platform base (63) and fixed coordinate of the hinge point on a compensation plate (61) in the wave compensation device (6);

calculating the difference between the real-time length of the driving cylinder (65) and the length of the driving cylinder at the initial position to obtain the compensation quantity of the driving cylinder (65);

the master control platform (2) sends a control instruction according to the compensation quantity of the driving electric cylinder (65) to control the driving electric cylinder (65) to move;

the steps are repeated, and real-time compensation of sea wave interference motion is achieved.