Simulation method, medium and equipment for riser load control under sinusoidal motion excitation

Abstract

The present invention relates to a method, medium and equipment for simulating load control of a watertight pipe under sinusoidal motion excitation, the method comprising the following steps: using a motion excitation module to realize the sinusoidal motion set by the user; using a control module to obtain user input information under the sinusoidal motion set by the user; using a signal acquisition module to obtain the top axial load data of the watertight pipe scale model, the displacement data and pressure data of the watertight pipe suspension system at the current sampling time; based on the user input information and the information collected by the signal acquisition module, judging whether the load of the watertight pipe scale model exceeds the set range, and if it exceeds, controlling the watertight pipe suspension system to move to adjust the dynamic load of the watertight pipe scale model. The present invention can effectively increase the minimum load of the watertight pipe or reduce the maximum load of the watertight pipe by controlling the watertight pipe suspension system, effectively preventing the watertight pipe from fracture failure or dynamic compression failure under extreme environmental conditions, and ensuring the safety of the watertight pipe.

Description

Technical Field

[0001] The invention relates to a riser load control simulation method, medium and equipment under sinusoidal motion excitation, belonging to the technical field of marine drilling and production. Background Art

[0002] During offshore drilling operations, the drilling riser, as an important equipment of the drilling platform, connects the drilling platform with the seabed wellhead, forms a channel separated from the seawater between the drilling platform and the seabed wellhead, and returns mud and lowers the drilling tools in the channel. In emergency situations such as typhoons, the riser is disconnected from the wellhead and is in a suspended state. In the hard suspension mode, the riser is stimulated by the heave movement of the drilling platform and undergoes intense axial movement, which may cause dynamic compression at the top of the riser buoyancy area, resulting in buckling failure; or the platform heave movement and the riser wet overlap may cause the riser suspension short section to have a great tension at the top and yield and break. Although the soft suspension method is usually considered to alleviate the load state of the suspended riser, the soft suspension mode requires the telescopic joint to be connected and the tensioner system to be connected, so the operation steps are relatively cumbersome, and it is usually necessary to operate in the moon pool area. In severe sea conditions such as typhoons, the operation is difficult and risky, and difficult to implement. Summary of the invention

[0003] In response to the above technical problems, the present invention provides a riser load control simulation method, medium and equipment under sinusoidal motion excitation. The present invention proposes this control simulation method to address the problems that riser avoidance measures are cumbersome and riser failure is prone to occur during typhoons, thereby providing safety protection for deep-water operations during typhoons.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for simulating riser load control under sinusoidal motion excitation, the method is based on a riser load control simulation device, the device comprising: a control system; a riser system, comprising a riser scale model and a bottom assembly scale model, the bottom assembly scale model being suspended at the lower end of the riser scale model; a riser suspension system, comprising a hydraulic system, a suspension nipple and a hollow annular hydraulic cylinder, the hydraulic system being connected to the control system and the hollow annular hydraulic cylinder, the upper end of the suspension nipple being suspended in the cavity of the hollow annular hydraulic cylinder, and the lower end being connected to the riser scale model; an excitation system, comprising a six-degree-of-freedom motion platform, the hollow annular hydraulic cylinder being assembled on the six-degree-of-freedom motion platform;

[0006] The control system includes: a motion excitation module, a control execution module connected to the motion excitation module; a signal acquisition module, respectively connected to the six-degree-of-freedom motion platform and the watertight pipe scale model; a control module, respectively connected to the signal acquisition module and the control execution module;

[0007] The steps include:

[0008] Using the motion excitation module to realize the sinusoidal motion set by the user;

[0009] Using the control module to obtain the user input information under the sinusoidal motion set by the user;

[0010] The signal acquisition module is used to obtain the top axial load data of the scaled riser model, the displacement data and the pressure data of the riser suspension system at the current sampling time;

[0011] Based on the user input information and the information collected by the signal acquisition module, it is determined whether the load of the watertight pipe scale model exceeds a set range. If exceeded, the watertight pipe suspension system is controlled to move to adjust the dynamic load of the watertight pipe scale model.

[0012] The watertight pipe load control simulation method described above, preferably, the signal acquisition module includes a force sensor, a displacement sensor and a pressure sensor, the force sensor is used to collect the top axial load of the watertight pipe scale model, and the displacement sensor and the pressure sensor are used to collect the displacement and pressure of the watertight pipe suspension system.

[0013] In the riser load control simulation method, preferably, the user input information includes: the maximum value, minimum value, and top axial dynamic load compensation rate of the riser scale model, the displacement limit value and pressure operating range of the riser suspension system, and the upper expected load and the lower expected load in the control process calculated based on the maximum value, minimum value, and top axial dynamic load compensation rate of the riser scale model.

[0014] In the watertight pipe load control simulation method, preferably, the control execution module also includes a pressure release and replenishment device, which is arranged on the six-degree-of-freedom motion platform and is used to keep the pressure of the watertight pipe suspension system within the pressure operating range of the watertight pipe suspension system set by the user.

[0015] The watertight pipe load control simulation method described above, preferably, the device also includes a water tank, and the lower part of the watertight pipe scale model and the bottom assembly scale model are arranged in the water tank.

[0016] The riser load control simulation method described above, preferably, the device also includes a bladder accumulator and a proportional throttle valve for driving and accurately controlling the hollow annular hydraulic cylinder.

[0017] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the computer program implements the steps of the above method when executed by a processor.

[0018] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0019] The present invention adopts the above technical solution, which has the following advantages:

[0020] The riser load control simulation method provided by the present invention can monitor the riser load, determine whether the riser load exceeds the user-set range, and decide whether to control the riser load according to the determination result. Therefore, by controlling the riser load, the minimum riser load can be effectively increased or the maximum riser load can be reduced, effectively preventing the riser from fracture failure or dynamic compression failure under extreme environmental conditions, thereby ensuring the safety of the riser. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a riser load control device under sinusoidal motion excitation provided by an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a control system in a riser load control device under sinusoidal motion excitation provided in this embodiment of the present invention;

[0023] Figure 3 A flow chart of a method for controlling a riser load under sinusoidal motion excitation provided by an embodiment of the present invention;

[0024] Figure 4 A diagram showing the experimental results of riser load control under sinusoidal motion excitation provided in this embodiment of the present invention;

[0025] Figure 5 A second experimental result diagram of riser load control under sinusoidal motion excitation provided in this embodiment of the present invention;

[0026] Figure 6 A third experimental result diagram of riser load control under sinusoidal motion excitation provided in this embodiment of the present invention;

[0027] The marks are as follows:

[0028] 1-bladder accumulator; 2-ball valve; 3-proportional throttle valve; 4-relief valve; 5-control system; 6-dosing pump; 7-cooler; 8-oil tank; 9-water surface; 10-ground; 11-bottom assembly scale model; 12-rise pipe scale model; 13-articulated joint; 14-six-degree-of-freedom motion platform; 15-hollow annular hydraulic cylinder; 16-suspension short section;

[0029] 501 - control module; 502 - control execution module; 503 - motion excitation module; 504 - signal acquisition module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0031] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second", "third", "fourth" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0032] The riser load control simulation method provided by the present invention can monitor the riser load, determine whether the riser load exceeds the user-set range, and decide whether to control the riser load according to the determination result. Therefore, by controlling the riser load, the minimum riser load can be effectively increased or the maximum riser load can be reduced, effectively preventing the riser from fracture failure or dynamic compression failure under extreme environmental conditions, thereby ensuring the safety of the riser.

[0033] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0034] like Figure 1 As shown, the riser load control simulation device under sinusoidal motion excitation provided by the present invention comprises:

[0035] Control system 5;

[0036] The watertight pipe system includes a watertight pipe scale model 12 and a bottom assembly scale model 11, wherein the bottom assembly scale model 11 is suspended at the lower end of the watertight pipe scale model 12;

[0037] The watertight pipe suspension system includes a hydraulic system, a suspension nipple 16 and a hollow annular hydraulic cylinder 15. The hydraulic system is connected to the control system 5 and the hollow annular hydraulic cylinder 15. The upper end of the suspension nipple 16 is suspended in the cavity of the hollow annular hydraulic cylinder 15, and the lower end is connected to the watertight pipe scale model 12.

[0038] The excitation system includes a six-degree-of-freedom motion platform 14, and a hollow annular hydraulic cylinder 15 is assembled on the six-degree-of-freedom motion platform 14;

[0039] Furthermore, it also includes a water tank, in which the lower part of the watertight pipe scale model 12 and the bottom assembly scale model 11 are arranged.

[0040] Furthermore, it also includes a bladder accumulator 1 for driving the hollow annular hydraulic cylinder 15. The bladder accumulator 1 provides fuel energy through the oil tank 8, stores energy, and then transmits the energy to the hollow annular hydraulic cylinder 15. The proportional throttle valve 3 accurately controls the speed of the hollow annular hydraulic cylinder 15. The hollow annular hydraulic cylinder 15 drives the suspension short section 16 to move, and the watertight pipe scale model 12 moves under the drive of the suspension short section 16.

[0041] like Figure 2 As shown, the control system 5 in the riser load control simulation device under sinusoidal motion excitation provided by the present invention includes:

[0042] The motion excitation module 503 is used to realize the sinusoidal motion set by the user and send it to the six-degree-of-freedom motion platform 14 to generate the sinusoidal motion;

[0043] The control execution module 502 is connected to the motion excitation module 503 and is used to generate additional motion to further drive the suspension nipple 16 and the riser scale model 12 to move;

[0044] The signal acquisition module 504 is connected to the six-degree-of-freedom motion platform 14 and the scaled riser model 12, respectively, and is used to collect the top axial load of the scaled riser model 12 and the displacement and pressure of the riser suspension system;

[0045] The control module 501 is connected to the signal acquisition module 504 and the control execution module 502 respectively, and is used to obtain user input information, obtain and process the data generated by the signal acquisition module 504, and send control instructions to the control execution module 502 to control the action of the proportional throttle valve 3, thereby controlling whether the hollow annular hydraulic cylinder 15 in the watertight pipe suspension system moves.

[0046] The control logic of the system of the present invention is as follows: the six-degree-of-freedom motion platform 14 provides a constant heave (axial) excitation motion for simulating the motion of an offshore drilling platform (motion 1), and determines whether the load control threshold is exceeded based on the collected load information of the watertight pipe scale model 12. When the threshold is exceeded, the watertight pipe suspension system is operated to complete the specified action (motion 2), thereby achieving the purpose of load control (the action execution device is a hollow annular hydraulic cylinder 15, and the control device is a control system 5. The top action of the watertight pipe scale model 12 after control is equivalent to superimposing a motion on the basis of the motion of the six-degree-of-freedom motion platform 14: motion 1+motion 2).

[0047] Furthermore, the signal acquisition module 504 includes a force sensor, a displacement sensor and a pressure sensor. The force sensor is used to collect the top axial load of the watertight pipe scale model 12, and the displacement sensor and the pressure sensor are used to collect the displacement and pressure of the watertight pipe suspension system.

[0048] Furthermore, the user input information includes: the maximum value, minimum value, and top axial dynamic load compensation rate of the watertight pipe scale model 12, the displacement limit value and pressure operating range of the watertight pipe suspension system, and the upper expected load and the lower expected load in the control process calculated according to the maximum value, minimum value, and top axial dynamic load compensation rate of the watertight pipe scale model 12.

[0049] Furthermore, the control execution module 502 also includes a pressure release and replenishment device, which is arranged on the watertight pipe suspension system and is used to keep the pressure of the watertight pipe suspension system within the watertight pipe suspension system pressure working range set by the user.

[0050] Based on the above riser load control simulation device, the present invention also provides a control method of the device, comprising the following steps:

[0051] Step 101: Obtain user input information through the touch screen or control panel, and obtain the status information of the scaled riser model 12 through the signal acquisition module 504, and determine the load change state of the scaled riser model 12 according to the status information.

[0052] Step 102: Determine whether the dynamic load of the scaled riser model 12 at the current sampling time needs to be controlled, that is, determine whether the dynamic load of the scaled riser model 12 exceeds the range set by the user. If it exceeds the range set by the user, it means that the load of the scaled riser model 12 needs to be controlled; if it is determined that it exceeds the load range set by the user, execute step 103; if it does not exceed the load range set by the user, return to step 101.

[0053] Step 103: Control the movement of the hollow annular hydraulic cylinder 15 in the watertight pipe suspension system to achieve load control of the watertight pipe scale model 12.

[0054] Furthermore, the control method of the riser load control simulation device comprises the following specific steps:

[0055] Obtain the maximum value, minimum value and top axial dynamic load compensation rate of the scaled model 12 of the watertight pipe under sinusoidal motion set by the user, and calculate the upper expected load and the lower expected load in the control process according to the maximum value, minimum value and top axial dynamic load compensation rate of the scaled model 12 of the watertight pipe set by the user; obtain the displacement limit value and pressure working range of the watertight pipe suspension system set by the user;

[0056] Acquire axial load information of the scaled riser model 12 at a current sampling time under sinusoidal motion from a force sensor, wherein the axial load information includes top axial load data of the scaled riser model 12;

[0057] If it is determined that the top axial load data of the watertight pipe scale model 12 is less than the upper expected load and greater than the lower expected load, the hollow annular hydraulic cylinder 15 does not act; if it is determined that the top axial load data of the watertight pipe scale model 12 is greater than or equal to the upper expected load, the hollow annular hydraulic cylinder 15 acts to reduce the top axial load of the watertight pipe scale model 12, and controls the top axial load of the watertight pipe scale model 12 to remain in a small range of fluctuations above and below the upper expected load, until the top axial load data of the watertight pipe scale model 12 is less than the upper expected load, and the hollow annular hydraulic cylinder 15 stops acting; if it is determined that the top axial load data of the watertight pipe scale model 12 is less than or equal to the lower expected load, the hollow annular hydraulic cylinder 15 acts to increase the top axial load of the watertight pipe scale model 12, and controls the top axial load of the watertight pipe scale model 12 to remain in a small range of fluctuations above and below the lower expected load, until the top axial load data of the watertight pipe scale model 12 is greater than the lower expected load, and the hollow annular hydraulic cylinder 15 stops acting;

[0058] Acquire the displacement data of the riser suspension system at the current sampling time from the displacement sensor;

[0059] If it is determined that during the action of the hollow annular hydraulic cylinder 15, the displacement of the riser suspension system at the current sampling time is greater than or equal to the displacement limit value of the riser suspension system set by the user, that is, it exceeds the stroke setting value of the hollow annular hydraulic cylinder 15, the hollow annular hydraulic cylinder 15 will stop acting immediately; if the displacement of the hollow annular hydraulic cylinder 15 in the riser suspension system at the current sampling time is greater than or equal to the displacement limit value of the riser suspension system set by the user, causing the riser suspension system to stop acting, the top axial load data of the riser scale model 12 is greater than or equal to the upper expected load or less than or equal to the lower expected load, and the riser suspension system will not act;

[0060] Acquire system pressure data of the riser suspension system at the current sampling time from the pressure sensor;

[0061] If it is determined that the pressure value of the riser suspension system at the current sampling time is greater than or less than the pressure operating range of the riser suspension system set by the user, the riser suspension system executes corresponding pressure release or supplementary measures.

[0062] Figure 4-Figure 6 The load control curves of the watertight pipe system when the motion amplitude of the six-degree-of-freedom motion platform 14 is 0.2m, the period is 10s, the motion amplitude is 0.22m, the period is 8s, and the motion amplitude is 0.16m, the period is 7s. The figure is divided into the "before control" load curve when the control system 5 is not controlled, the expected "ideal control" load curve under control, and the "actual control" curve actually monitored by the sensor under control. The results of the figure show that the proposed watertight pipe load model method, medium and equipment under sinusoidal motion excitation can realize the dynamic load compensation of the watertight pipe system.

[0063] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above control method when executed by a processor.

[0064] A fourth aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above control method when executing the computer program.

[0065] The present invention is described in terms of flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to specific embodiments. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0066] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0067] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0068] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a disk, etc., and includes several instructions for enabling a computer device to execute the methods described in various embodiments of the present invention or certain parts of the embodiments.

[0069] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including preferred examples and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simulating riser load control under sinusoidal motion excitation, comprising a device including a riser system, a riser suspension system, an excitation system and a control system, wherein the riser system includes a scaled riser model, the excitation system includes a six-degree-of-freedom motion platform, and the control system includes: A motion excitation module and a control execution module connected to the motion excitation module; A signal acquisition module is connected to the six-degree-of-freedom motion platform and the scaled model of the riser respectively; a control module is connected to the signal acquisition module and the control execution module respectively; It is characterized by comprising the following steps: Using the motion excitation module to realize the sinusoidal motion set by the user; Using the control module to obtain user input information under the sinusoidal motion set by the user; The signal acquisition module is used to obtain the top axial load data of the scaled riser model, the displacement data and the pressure data of the riser suspension system at the current sampling time; Based on the user input information and the information collected by the signal acquisition module, determine whether the load of the scaled riser model exceeds a set range, and if so, control the riser suspension system to move to adjust the dynamic load of the scaled riser model; Obtain the maximum value, minimum value and top axial dynamic load compensation rate of the scaled model of the watertight pipe under the sinusoidal motion set by the user, and calculate the upper expected load and the lower expected load in the control process according to the maximum value, minimum value and top axial dynamic load compensation rate of the scaled model of the watertight pipe set by the user; obtain the displacement limit value and pressure working range of the watertight pipe suspension system set by the user; Acquire axial load information of the scaled riser model at a current sampling time under sinusoidal motion from a force sensor, wherein the axial load information includes top axial load data of the scaled riser model; If it is determined that the top axial load data of the scaled riser model is less than the upper expected load and greater than the lower expected load, the hollow annular hydraulic cylinder will not act; if it is determined that the top axial load data of the scaled riser model is greater than or equal to the upper expected load, the hollow annular hydraulic cylinder will act to reduce the top axial load of the scaled riser model, and control the top axial load of the scaled riser model to remain in a small range of fluctuations above and below the upper expected load, until the top axial load data of the scaled riser model is less than the upper expected load, and the hollow annular hydraulic cylinder will stop acting; if it is determined that the top axial load data of the scaled riser model is less than or equal to the lower expected load, the hollow annular hydraulic cylinder will act to increase the top axial load of the scaled riser model, and control the top axial load of the scaled riser model to remain in a small range of fluctuations above and below the lower expected load, until the top axial load data of the scaled riser model is greater than the lower expected load, and the hollow annular hydraulic cylinder will stop acting; Acquire the displacement data of the riser suspension system at the current sampling time from the displacement sensor; If it is determined that during the action of the hollow annular hydraulic cylinder, the displacement of the riser suspension system at the current sampling time is greater than or equal to the displacement limit value of the riser suspension system set by the user, that is, it exceeds the stroke setting value of the hollow annular hydraulic cylinder, then the hollow annular hydraulic cylinder immediately stops action; if the displacement of the hollow annular hydraulic cylinder in the riser suspension system at the current sampling time is greater than or equal to the displacement limit value of the riser suspension system set by the user, causing the riser suspension system to stop action, then the top axial load data of the riser scale model is greater than or equal to the upper expected load or less than or equal to the lower expected load, and the riser suspension system does not act; Acquire system pressure data of the riser suspension system at the current sampling time from the pressure sensor; If it is determined that the pressure value of the riser suspension system at the current sampling time is greater than or less than the pressure operating range of the riser suspension system set by the user, the riser suspension system executes corresponding pressure release or supplementary measures.

2. The riser load control simulation method according to claim 1, characterized in that: The signal acquisition module includes a force sensor, a displacement sensor and a pressure sensor. The force sensor is used to collect the top axial load of the watertight pipe scale model, and the displacement sensor and the pressure sensor are used to collect the displacement and pressure of the watertight pipe suspension system.

3. The riser load control simulation method according to claim 1, characterized in that: The user input information includes: the maximum value, minimum value, and top axial dynamic load compensation rate of the watertight pipe scale model, the displacement limit value and pressure operating range of the watertight pipe suspension system, and the upper expected load and the lower expected load in the control process calculated based on the maximum value, minimum value, and top axial dynamic load compensation rate of the watertight pipe scale model.

4. The riser load control simulation method according to claim 1, characterized in that: The control execution module also includes a pressure release and replenishment device, which is arranged on the watertight pipe suspension system and is used to keep the pressure of the watertight pipe suspension system within the pressure working range of the watertight pipe suspension system set by the user.

5. The riser load control simulation method according to claim 1, characterized in that: The device also includes a water tank, in which the lower part of the watertight pipe scale model and the bottom assembly scale model are arranged.

6. The riser load control simulation method according to claim 1, characterized in that: The device also includes a bladder accumulator and a proportional throttle valve for driving and accurately controlling the hollow annular hydraulic cylinder.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 are implemented.

8. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to claim 1 are implemented.

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