An adjustable water supply system with variable air gap height and control method thereof

Abstract

The present invention discloses an adjustable water supply system with variable air gap height, which is arranged on a lifting drilling platform, wherein the lifting drilling platform comprises a main hull, a living building roof, a cantilever beam drilling platform and pile legs; the main hull can be lifted up and down relative to the pile legs to adjust the air gap height; the living building roof is arranged on the upper side of one end of the main hull; the cantilever beam drilling platform is arranged on the upper side of the other end of the main hull, and can slide horizontally relative to the main hull; the adjustable water supply system comprises a submersible pump, a cooling equipment assembly and a pipeline assembly; the cooling equipment assembly comprises a first cooling equipment arranged on the living balcony; a second cooling equipment and a third cooling equipment arranged on the cantilever beam drilling platform; a fourth cooling equipment and a fifth cooling equipment arranged on the main hull; the pressure in the pipeline assembly is detected by a pressure gauge, and then the opening and closing degree of the regulating valve is adjusted to achieve water supply regulation under different air gap heights.

Description

Technical Field

[0001] The invention relates to the technical field of seawater supply cooling systems on a lifting drilling platform, and in particular to an adjustable water supply system with variable air gap height and a control method thereof. Background Art

[0002] There are many devices that need to be cooled on the lifting drilling platform, which are located on the main hull, the roof of the living building and the cantilever drilling platform. The main hull can be raised and lowered relative to the pile legs. The distance between the bottom of the main hull and the sea surface is the air gap height, which changes according to the different operating sea areas and belongs to a variable air gap; the cantilever drilling platform is integrated and can slide relative to the main hull. The equipment on the drilling platform has the highest altitude. The roof of the living building is fixed relative to the main hull but is located above the main deck of the main hull and has a higher altitude. The main hull has the lowest altitude.

[0003] The above three areas all have cooling equipment and require seawater systems to provide cooling. At present, the general seawater supply system of drilling platforms is designed to first supply water to the seawater tank by a submersible pump, and then the seawater service pumps in each zone pump water from the seawater tank to supply their respective areas, such as Figure 1 As shown in the figure, this system design has the following main disadvantages and shortcomings: a submersible pump is required to supply the seawater tank first, and multiple pumps with different pressures and flows draw water from the seawater tank and deliver it to the cooling equipment, making the system large and bloated. A large number of pumps take up space on the platform and require additional power and cable channels. Summary of the invention

[0004] The present invention aims to overcome at least one defect of the above-mentioned prior art and provides an adjustable water supply system with variable air gap height, which is arranged on a lifting drilling platform, and the lifting drilling platform includes a main hull, a living building roof, a cantilever beam drilling platform and pile legs; the main hull can be raised and lowered relative to the pile legs to adjust the air gap height; the living building roof is arranged on the upper side of one end of the main hull; the cantilever beam drilling platform is arranged on the upper side of the other end of the main hull and can slide horizontally relative to the main hull; the height of the cantilever beam drilling platform from the bottom of the ship is greater than the height of the living building roof from the bottom of the ship. The adjustable water supply system includes a submersible pump, a cooling equipment assembly and a pipeline assembly; the cooling equipment assembly includes a first cooling equipment arranged on the living balcony; a second cooling equipment and a third cooling equipment arranged on the cantilever beam drilling platform; a fourth cooling equipment and a fifth cooling equipment arranged on the main hull; the submersible pump and the cooling equipment assembly are connected through the pipeline assembly; a plurality of regulating valves and pressure gauges are provided on the pipeline assembly, and the pressure in the pipeline assembly is detected by the pressure gauge, and then the opening and closing degree of the regulating valve is adjusted to achieve water supply regulation under different air gap heights.

[0005] The lifting drilling platform described in the present invention is provided with a plurality of pile legs, so that the main hull can move up and down relative to the pile legs to achieve the adjustment of different air gap heights. The roof of the living building is arranged on the upper side of one end of the main hull, so the potential energy of the cooling equipment on the roof of the living building will be greater than the potential energy of the cooling equipment on the main hull. The cantilever beam drilling platform is arranged on the upper side of the other end of the main hull, and can slide horizontally relative to the main hull; the cantilever beam drilling platform can be horizontally moved relative to the main hull by designing a track on the main hull. The present invention designs a total of five cooling devices, including a first cooling device on the roof of the living building, a second cooling device and a third cooling device on the cantilever beam drilling platform, which are connected in parallel with each other; and a fourth cooling device and a fifth cooling device designed on the main hull and connected in parallel. In order to meet the needs of systems of different volumes, the design of different numbers of cooling devices can be executed according to the system, i.e., the control method of the present invention.

[0006] Furthermore, the pipeline assembly includes a first pipeline, a second pipeline and a third pipeline; the first pipeline connects the submersible pump with the fourth cooling device and the fifth cooling device on the main hull; the second pipeline connects the submersible pump with the first cooling device on the living balcony; the third pipeline connects the submersible pump with the second cooling device and the third cooling device on the cantilever beam drilling platform; the inlet end of the fourth cooling device and the fifth cooling device is provided with a first pressure gauge, and the outlet end of the fourth cooling device and the fifth cooling device is respectively provided with a first regulating valve and a second regulating valve; the inlet end of the first cooling device is provided with a second pressure gauge and a third regulating valve; the outlet end of the first cooling device is provided with a first seawater discharge port; the inlet end of the second cooling device and the third cooling device is provided with a third pressure gauge, and the outlet end is respectively provided with a fourth regulating valve and a fifth regulating valve.

[0007] Furthermore, a sixth regulating valve is provided at the junction of the outlet ends of the fourth cooling device and the fifth cooling device; the sixth regulating valve is connected to the second seawater discharge port provided at the bottom of the main hull, and a seventh regulating valve is also provided between the sixth regulating valve and the second seawater discharge port; an eighth regulating valve is provided on the pipeline after the outlet ends of the second cooling device and the third cooling device are joined; the eighth regulating valve is connected to the seventh regulating valve and the second seawater discharge port in sequence.

[0008] Furthermore, the first pipeline is a first hose at the connection between the cantilever beam drilling platform and the main hull; the outlet ends of the second cooling device and the third cooling device are provided with a return pipeline, and the return pipeline is a second hose at the connection between the cantilever beam drilling platform and the main hull, and a fourth pressure gauge is also provided at the outlet of the submersible pump.

[0009] The water supply system of the present invention is composed of a submersible pump, a first cooling device to a fifth cooling device, a first pipeline to a third pipeline, a first regulating valve to an eighth regulating valve, a first pressure gauge to a fourth pressure gauge, a first hose, a second hose, etc. The system is installed on a lifting drilling platform. The main hull of the drilling platform can be raised and lowered relative to the pile legs to adjust the air gap height, the cantilever beam drilling platform can slide relative to the main hull, and the first hose and the second hose are installed on the water supply and return pipe of the third pipeline, which can follow the movement when the cantilever beam drilling platform slides horizontally to maintain the continuous water supply function of the entire pipeline.

[0010] The present invention also protects a control method for an adjustable water supply system with a variable air gap height, the control method comprising the following steps:

[0011] S1: Adjust the air gap height to the required air gap height, the maximum adjustable air gap height is h;

[0012] S2: Start the submersible pump, gradually reduce the opening of the seventh regulating valve from full opening, and adjust the opening of the third regulating valve to the range of 10% to 30%, until the outlet pressure of the submersible pump is greater than the pressure converted from the potential energy of the cooling equipment component relative to the sea level;

[0013] S3: adjusting the third regulating valve on the second pipeline so that the pressure detected by the second pressure gauge is not greater than the threshold pressure set by the first cooling device;

[0014] S4: adjusting the sixth regulating valve and the eighth regulating valve so that the third pressure gauge is at a positive pressure and the pressure detected by the first pressure gauge is not greater than the maximum threshold pressure allowed by the fourth cooling device and the fifth cooling device;

[0015] S5: Simultaneously reduce the third regulating valve, the sixth regulating valve, and the seventh regulating valve; until the pressure detected by the third pressure gauge meets the minimum required pressure of the second cooling device and the third cooling device; and the pressure detected by the second pressure gauge is not greater than the threshold pressure set for the first cooling device;

[0016] S6: According to the demand for seawater by the second cooling device and the third cooling device, the fourth regulating valve and / or the fifth regulating valve are adjusted, and the valve opening size is operated in reverse to distribute the seawater demand of the two devices; according to the fourth cooling device and the fifth cooling device, the first regulating valve and / or the second regulating valve are adjusted, and the valve opening size is operated in reverse to distribute the seawater demand of the two devices.

[0017] Furthermore, when the operating height of the lifting drilling platform is higher than the standard air gap height h1, the opening of the seventh regulating valve is reduced to increase the outlet pressure of the submersible pump and reduce the total flow rate; when the operating height of the lifting drilling platform is lower than the standard air gap height h1, the opening of the seventh regulating valve is increased to reduce the outlet pressure of the submersible pump and increase the total flow rate.

[0018] The control method according to claim 5 is characterized in that the pipe size of the pipe assembly of the adjustable water supply system satisfies the formula Where Q 6i is the flow requirement of each pipeline, that is, the equipment flow requirement, V i is the flow velocity in the pipe, the value range is: 2m / s≤V i ≤3m / s.

[0019] Furthermore, the rated displacement Q of the submersible pump B1 Q is the seawater cooling demand of each cooling equipment under drilling conditions Ji The sum of the two, taking a 20% margin, satisfies the formula: Rated pressure p B1 Satisfy the public notice: P B1 =ρg(h 1 +h 3 )+P 0 ; where h1 is the standard air gap height, h3 is the height of the cantilever beam drilling platform relative to the bottom of the ship, P 0 1~5bar.

[0020] The control method according to claim 5 is characterized in that the opening of the regulating valve is R=0-1, wherein in the step S2, the seventh regulating valve is gradually lowered from R=1, wherein the opening of the third regulating valve is adjusted to the interval; until the fourth pressure gauge measures the outlet pressure of the submersible pump P2≥ρg(h 1 +h 3 ), ρ is the seawater density, g is the acceleration due to gravity, h1 is the air gap height, and h3 is the height from the drilling platform to the bottom of the ship.

[0021] Furthermore, the adjustable water supply system is adjusted within a maximum adjustable air gap height h, and the maximum adjustable air gap height h satisfies the following formula: where h z1-z2 is the pipeline energy loss, P1 is the required pressure of the cantilever drilling platform (3); h max The pump operating point head height for regulating the pump flow rate of the jack-up drilling platform is limited to the maximum air gap h.

[0022] Specifically, in step S1, the equipment layout and system design are first confirmed: the lifting drilling platform is lifting type, and the standard operating air gap height is h1. The submersible pump is inserted below the sea level, and the outlet of the submersible pump is divided into three pipelines, namely the first pipeline, the second pipeline and the third pipeline. The first pipeline goes to the fourth cooling device and the fifth cooling device of the main hull. After the seawater cools the fourth cooling device and the fifth cooling device, it is connected to the main hull outlet, and a sixth regulating valve is installed on the outlet manifold of the fourth cooling device and the fifth cooling device. The second pipeline is transmitted to the roof of the living building to supply cooling water to the first cooling device. The first cooling device is large in size and requires a large amount of water, but the required pressure is small, requiring a pressure ≤ P4, and P4 can be 0.5 bar. After the seawater cools the first cooling device, it is directly discharged into the sea. The first cooling device has a cooling water ventilation and overflow port. The first cooling device is placed on the roof of the living building. A second pressure regulating valve is installed in front of the first cooling device to reduce pressure to avoid overflow from the ventilation port. The third pipeline is connected to the cantilever rig equipment. The equipment pressure requirement is ≥P5, and P5 can be 0.8 bar. After the seawater cools the second cooling equipment and the third cooling equipment, it returns to the main hull and returns to the second seawater discharge port on the collection pipe close to the main hull, and the eighth regulating valve is set. The seawater in the third pipeline is collected and discharged to the sea after cooling the seawater in the first pipeline. The second seawater discharge port is set with a total regulating valve, that is, the seventh regulating valve. Pressure gauges are installed at the outlet of the submersible pump and on each equipment pipeline to detect the pressure. Among them, h1 is the platform design air gap height, and h3 is the height of the cantilever rig relative to the bottom of the ship.

[0023] S2: Start the submersible pump, gradually reduce the opening of the seventh regulating valve from fully open R=1, and adjust the opening of the third regulating valve to the range of R=(0.1-0.3) until the outlet pressure of the submersible pump is greater than the pressure converted from the potential energy of each cooling device relative to the sea level.

[0024] S3: The third regulating valve on the second pipeline is adjusted up and down, and the second pressure gauge is checked to confirm that the pressure after decompression is not greater than the maximum allowable pressure of the first cooling device.

[0025] S4. The openings of the sixth and eighth regulating valves are adjusted alternately to smaller values. The third pressure gauge is checked to confirm that the pressure on the drilling platform rises to positive pressure. At the same time, the first pressure gauge is checked to confirm that the inlet pressures of the fourth and fifth cooling devices on the first pipeline of the main hull do not exceed the maximum allowable pressure of the devices.

[0026] S5: The valve openings of the seventh regulating valve, the third regulating valve, and the sixth regulating valve are simultaneously slightly reduced until the pressure on the drilling floor (the third pressure gauge) rises to the minimum pressure required by the equipment. At the same time, check the second pressure gauge on the second pipeline. If it exceeds the maximum allowable pressure of the first cooling device, the opening of the third regulating valve is further reduced to be less than the maximum allowable pressure of the equipment.

[0027] S6. After the pressure of the first pipeline, the second pipeline, and the third pipeline are adjusted in place, the first regulating valve, the second regulating valve, or the fourth regulating valve and the fifth regulating valve of each branch can be adjusted. The opening of the branch with large flow demand is increased, and the opening of the branch with small flow demand is decreased, so as to achieve the balance of water demand of each branch equipment. For example, when seawater reaches the second cooling equipment on the drilling platform, the third cooling equipment is divided into two branches. If the opening of the fifth regulating valve is reduced and the opening of the fourth regulating valve is increased, the flow of the branch of the third cooling equipment will decrease, and the flow of the branch of the second cooling equipment will increase; if the opening of the fifth regulating valve is increased and the opening of the fourth regulating valve is reduced, the flow of the branch of the third cooling equipment will increase, and the flow of the branch of the second cooling equipment will decrease.

[0028] S7: If the platform needs to operate at a higher air gap than the standard h1, the distance between the entire platform and the sea surface will increase, that is, the distance between each device and the sea surface will increase. If the valve opening is maintained according to the S2-S6 steps, the inlet pressure of each device will decrease. To maintain the original pressure, it is necessary to adjust the seventh regulating valve opening to further reduce it, so as to adjust the outlet pressure of the submersible pump to increase and the total flow rate to decrease. When the platform is operating below the standard air gap h1, the air gap becomes smaller, and the distance between each device and the sea surface becomes smaller. If the valve opening is maintained according to the S2-S6 steps, the inlet pressure of each device will increase. To maintain the original pressure, the seventh regulating valve opening is adjusted to further increase it, so as to adjust the outlet pressure of the pump to decrease and the total flow rate to increase.

[0029] The above adjustments are based on the pump characteristic curve. If the seventh regulating valve opening is reduced, that is, the flow rate is reduced, then the pressure on the corresponding curve will increase to overcome the pressure drop caused by the platform rising. If the seventh regulating valve opening is increased, that is, the flow rate is increased, then the pressure on the corresponding curve will decrease to reduce and offset the pressure increase on the pipeline caused by the platform falling. However, according to the pump characteristic curve, it can only be adjusted within a certain range, and the adjusted flow rate must meet the seawater cooling demand Q of each equipment under drilling conditions. Ji sum Q J0 , the platform is limited to adjust the pump flow at the maximum air gap h.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The adjustable water supply system with variable air gap height of the present invention does not need to design a seawater tank, so that the main hull has more accommodating space, and does not need a submersible pump to supply the seawater tank first. The entire system has a simple structure and high efficiency. At the same time, the adjustable water supply system of the present invention only needs one submersible pump to provide cooling seawater to multiple cooling devices with different potential energies, reducing the setting of additional electricity and cable channels, greatly saving occupied space and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the multi-pump water supply method in the background technology.

[0033] Figure 2 The invention discloses an adjustable water supply system with variable air gap height.

[0034] Figure 3 This is a comparison curve of the opening and the pressure drop in Example 2 of the present invention.

[0035] Figure 4 This is the pump characteristic curve in Example 2 of the present invention.

[0036] Figure 5 This is the simulation result under the standard air gap in Example 2 of the present invention.

[0037] Figure 6 This is the simulation result of Example 2 of the present invention under the condition of higher than standard air gap. DETAILED DESCRIPTION

[0038] The drawings in the embodiments provide a more detailed description of the technical solutions in the embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0039] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0040] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0041] Example 1

[0042] like Figure 2 The adjustable water supply system with variable air gap height is provided on a lifting drilling platform, and the lifting drilling platform includes a main hull 1, a living building roof 2, a cantilever beam drilling platform 3 and pile legs 4; the main hull 1 can be raised and lowered relative to the pile legs 4 to adjust the air gap height; the living building roof 2 is provided on the upper side of one end of the main hull 1; the cantilever beam drilling platform 3 is provided on the upper side of the other end of the main hull 1, and can slide horizontally relative to the main hull 1; the adjustable water supply system includes a submersible pump 5, a cooling equipment component and a pipeline assembly The cooling equipment assembly comprises a first cooling equipment 61 arranged on the living balcony; a second cooling equipment 62 and a third cooling equipment 63 arranged on the cantilever beam drilling platform 3; a fourth cooling equipment 64 and a fifth cooling equipment 65 arranged on the main hull 1; the submersible pump 5 and the cooling equipment assembly are connected through the pipeline assembly; a plurality of regulating valves and pressure gauges are arranged on the pipeline assembly, and the pressure in the pipeline assembly is detected by the pressure gauge, and then the opening and closing degree of the regulating valve is adjusted to achieve water supply regulation under different air gap heights.

[0043] The pipeline assembly includes a first pipeline 71, a second pipeline 72 and a third pipeline 73; the first pipeline 71 connects the submersible pump 5 with the fourth cooling device 64 and the fifth cooling device 65 on the main hull 1; the second pipeline 72 connects the submersible pump 5 with the first cooling device 61 on the living balcony, and the first cooling device 61 is connected to the first seawater discharge port 10; the third pipeline 73 connects the submersible pump 5 with the second cooling device 62 and the third cooling device 63 on the cantilever beam drilling platform 3; the inlet end of the fourth cooling device 64 and the fifth cooling device 65 is provided with a first pressure gauge 81, and the outlet end of the fourth cooling device 64 and the fifth cooling device 65 is respectively provided with a first regulating valve 91 and a second regulating valve 92; the inlet end of the first cooling device 61 is provided with a second pressure gauge 82 and a third regulating valve 93; the outlet end of the first cooling device 61 is provided with a first seawater discharge port 10; the inlet end of the second cooling device 62 and the third cooling device 63 is provided with a third pressure gauge 83, and the outlet end is respectively provided with a fourth regulating valve 94 and a fifth regulating valve 95.

[0044] A sixth regulating valve 96 is provided at the junction of the outlet ends of the fourth cooling device 64 and the fifth cooling device 65; the sixth regulating valve 96 is connected to the second seawater discharge port provided at the bottom of the main hull 1, and a seventh regulating valve 97 is provided between the sixth regulating valve 96 and the second seawater discharge port; an eighth regulating valve 98 is provided in the pipeline after the outlet ends of the second cooling device 62 and the third cooling device 63 are joined; the eighth regulating valve 98 is connected to the seventh regulating valve 97 and the second seawater discharge port in sequence.

[0045] The first pipeline 71 is a first hose 401 at the connection between the cantilever beam drilling platform 3 and the main hull 1; a return pipeline is provided at the outlet end of the second cooling device 62 and the third cooling device 63, and the return pipeline is a second hose 402 at the connection between the cantilever beam drilling platform 3 and the main hull 1, and a fourth pressure gauge 84 is also provided at the outlet of the submersible pump 5.

[0046] Example 2

[0047] This embodiment provides a control method for an adjustable water supply system with a variable air gap height. Figure 2 As shown, the specific steps include:

[0048] S1: Confirm equipment layout and system design: The platform is of lifting type, and the standard operating air gap height is h1. A submersible pump 5 is set up and inserted below the sea level. The outlet of the submersible pump 5 is divided into three pipelines: the first pipeline 71, the second pipeline 72, and the third pipeline 73. The first pipeline 71 goes to the fourth cooling device 64 and the fifth cooling device 65 of the main hull 1. After the seawater cools the above equipment, it is connected to the second seawater discharge port 20 designed for the main hull 1, and a fourth regulating valve 94 is installed on the parallel outlet collection pipes of the fourth cooling device 64 and the fifth cooling device 65. The second pipeline 72 goes to the roof 2 of the living building to supply cooling water to the first cooling device 61. The first cooling device 61 is large in size and requires a large amount of water, but the required pressure is small, requiring a pressure ≤ P4 (take 0.5 bar as an example). The seawater is directly discharged into the sea after the cooling device. The device has a cooling water ventilation and overflow port. The device is placed on the roof 2 of the living building. A second regulating valve 92 is installed in front of the first cooling device 61 to reduce pressure to prevent overpressure from overflowing from the ventilation port. The third pipeline 73 is connected to the cantilever beam drilling platform 3 equipment, and the equipment pressure requirement is ≥ P5 (take 0.8 bar as an example). After the seawater cools the second cooling equipment 62 and the third cooling equipment 63, it returns to the main hull 1. The third regulating valve 93 is set on the return collection pipe near the second seawater discharge port 20 of the main hull 1. The seawater in the third pipeline 73 and the seawater in the first pipeline 71 are cooled and discharged to the sea. The second seawater discharge port 20 is set with the first regulating valve 91 for total regulation. Pressure gauges are provided at the outlet of the submersible pump 5 and the pipelines of each equipment to detect the pressure.

[0049] The size of each pipeline is calculated according to the formula Calculate, where Q 6i is the flow requirement of each pipeline, that is, the equipment flow requirement; where V i is the flow velocity in the pipe, the value range is: 2m / s≤V i ≤3m / s, submersible pump 5 rated displacement Q B1 Q is the seawater cooling demand of each equipment under drilling conditions Ji The sum of the two, taking a 20% margin, is: Rated pressure p B1Designed to be the height potential energy from the cantilever beam drilling platform 3 to the sea surface plus more P 1 , that is: p B1 =ρg(h 1 +h 3 )+P 1

[0050] , where h1 is the designed air gap height of the platform and h3 is the height of the drilling platform relative to the bottom of the ship.

[0051] S2: Start the submersible pump 5, gradually reduce the opening of the first regulating valve 91 from full opening R = 1, and adjust the opening of the second regulating valve 92 to the range of R = 0.1-0.3. Figure 3 As shown in the figure, the opening adjustment and pressure drop comparison curve are all referred to in the following steps. The flow rate curves are changed until the outlet pressure of the submersible pump 5 (the fourth pressure gauge 84) is greater than the pressure converted from the potential energy of the cooling equipment of the drilling platform relative to the sea level, that is, the pressure p≥ρg(h 1 +h 3 ), ρ is the seawater density, g is the gravitational acceleration, h1 is the air gap height, and h3 is the height from the cantilever beam drilling platform 3 to the bottom of the ship.

[0052] S3: The second regulating valve 92 on the second pipeline 72 is adjusted up and down, and the second pressure gauge 82 is checked to confirm that the pressure after decompression is not greater than the maximum allowable pressure P4 of the first cooling device 61;

[0053] S4: The openings of the sixth regulating valve 96 and the eighth regulating valve 98 are adjusted alternately to decrease, and the third pressure gauge 83 is checked to confirm that the pressure on the drilling floor rises to a positive pressure. At the same time, the first pressure gauge 81 is checked to confirm that the inlet pressure of the fourth cooling device 64 on the first pipeline 71 of the main hull 1 pipeline does not exceed the maximum allowable pressure of the device.

[0054] S5: The openings of the third regulating valve 93, the sixth regulating valve 96, and the seventh regulating valve 97 are simultaneously slightly reduced until the drilling floor pressure (third pressure gauge 83) rises to the minimum pressure P3 required by the equipment (taken as 0.8 bar as an example). At the same time, the second pressure gauge 82 on the second pipeline 72 is checked. If it exceeds the maximum allowable pressure P4 of the first cooling device 61, the opening of the second regulating valve 92 is further reduced to be less than P4.

[0055] S6: After the pressure of the first pipeline 71, the second pipeline 72, and the third pipeline 73 are adjusted to the right position, the first regulating valve 91, the second regulating valve 92, or the fourth regulating valve 94, and the fifth regulating valve 95 of each branch can be adjusted, and the opening of the branch with large flow demand is increased, and the opening of the branch with small flow demand is decreased, so as to achieve the balance of water demand of each branch equipment. For example: when the seawater arrives at the drilling platform, it is divided into two branches according to the second cooling equipment 62 and the third cooling equipment 63. If the opening of the fifth regulating valve 95 is reduced and the opening of the fourth regulating valve 94 is increased, the flow of the branch of the third cooling equipment 63 is reduced, and the flow of the branch of the second cooling equipment 62 is increased; if the opening of the fifth regulating valve 95 is increased and the opening of the fourth regulating valve 94 is reduced, the flow of the branch of the third cooling equipment 63 is increased, and the flow of the branch of the second cooling equipment 62 is reduced.

[0056] S7. If the platform needs to operate at a higher air gap than the standard air gap h1, the distance between the entire platform and the sea surface will increase, that is, the distance between each device and the sea surface will increase. If the valve opening is maintained according to steps S2-S6, the inlet pressure of each device will decrease. To maintain the original pressure, it is necessary to adjust the opening of the first regulating valve 91 to further reduce it, so as to increase the pump outlet pressure and reduce the total flow. When the platform is operating below the standard air gap h1, the air gap becomes smaller, and the distance between each device and the sea surface becomes smaller. If the valve opening is maintained according to steps S2-S6, the inlet pressure of each device will increase. To maintain the original pressure, it is necessary to adjust the opening of the first regulating valve 91 to further increase it, so as to reduce the pump outlet pressure and increase the total flow. Figure 4 As shown, the above adjustment is based on the pump characteristic curve. If the opening of the first regulating valve 91 decreases, that is, the flow rate decreases, the pressure on the corresponding curve increases to overcome the pressure drop caused by the platform rising. If the opening of the first regulating valve 91 increases, that is, the flow rate increases, the pressure on the corresponding curve decreases to reduce and offset the pressure increase on the pipeline caused by the platform falling. However, according to the pump characteristic curve, it can only be adjusted within a certain range, and the adjusted flow rate must meet the seawater cooling demand Q of each equipment under drilling conditions. Ji sum Q J0 , that is, adjust within the shadow range of the pump characteristic curve. The standard design air gap height of the platform is h1. If the platform needs to be used higher than the design air gap, the flow rate in the pump characteristic curve is Q J0 The corresponding pressure is found to be p max , converted into lift height h max , the maximum air gap height can be inferred and calculated according to the following formula:

[0057]

[0058] where h z1-z2 is the pipeline energy consumption, P1 is the required pressure of the cantilever drilling platform 3;

[0059] like Figure 4As shown in the figure, the pump characteristic curve is shaded, that is, the platform is limited to adjust the pump flow under the maximum air gap h, and the pump working point head is h max .

[0060] The above adjustment method is based on fluid mechanics pipe network analysis. There are two theorems of material balance and energy conservation in the branch pipe network.

[0061] 1) Material balance - the sum of the seawater flow rates of each pipeline at each cross-sectional node is zero,

[0062]

[0063] Combination Figure 2 As shown, the first pipe 71, the second pipe 72, and the third pipe 73 of the three branches meet at the outlet pipe of the submersible pump 5. The mass flow rates of the three branches Q the first pipe 71, Q the second pipe 72, Q the third pipe 73 and the flow rate of the submersible pump 5 should be zero, that is,

[0064]

[0065] 2) Energy conservation - the energy relationship between any two cross-section nodes in the pipeline should comply with

[0066]

[0067] In an ideal fluid where multiple pipes converge, the above formula also applies, that is, the total energy head at any two nodes is a constant C, and the Bernoulli equation is as follows:

[0068]

[0069] Where P is the node pressure, v is the flow velocity, ρ is the air density, g is the gravitational acceleration, h is the potential energy height, and h z1-z2 is the energy loss of the two nodes. Substituting the known parameters into the equation can calculate the other unknowns.

[0070] In order to avoid complicated manual calculations, the CFD software FLOWMASTER is used here to perform simulation calculations to prove that the adjustment method under variable air gap is feasible, and the final results are used to verify the adjustment method and valve opening. A simplified model is established in the software.

[0071] 1 is set as the drilling platform working at the standard air gap of 15m, the second cooling device 62 and the third cooling device 63 of the drilling platform are 50m above sea level, the first cooling device 61 is 39m above sea level, the fourth cooling device 64 and the fifth cooling device 65 are 17m above sea level, and the rated working condition of the submersible pump 5 is 400m3 / h@60m. By directly setting the opening of the pressure regulating valve, the results are as follows Figure 5The data shows that under the appropriate opening, the submersible pump 5 is very close to working under the rated working condition of 0.011m3 / h@6.047bar (i.e. 400m3 / h@60m), the inlet pressure of the second cooling device 62 and the third cooling device 63 of the cantilever beam drilling platform 3 reaches 1.044bar to meet the use requirements, and the flow and pressure of the other pipelines are balanced to meet the requirements.

[0072] 2 It is assumed that the drilling platform works at a height of 5m above the standard air gap height, that is, at a height of 20m, the second cooling device 62 and the third cooling device 63 of the cantilever beam drilling platform 3 are at an altitude of 55m, the first cooling device 61 is at an altitude of 44m, and the fourth cooling device 64 and the fifth cooling device 65 are at an altitude of 22m. By directly setting the opening of the pressure regulating valve, the result is as follows Figure 6 , submersible pump 5 working condition is 0.0941m3 / h@6.485bar (ie 339m3 / h@65.4m), in line with Figure 4 The pump flow curve is in the shaded area and is within the adjustable range. The inlet pressure of the second cooling device 62 and the third cooling device 63 of the drilling platform reaches 1.036 bar, which meets the use requirements. The data shows that the flow of each device is relatively reduced, but the flow and pressure are balanced and still meet the requirements.

[0073] The above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit it. Although the present invention is described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention. Those skilled in the art may also make other changes within the spirit of the present invention and apply them to the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made according to the spirit of the present invention should be included in the scope of protection claimed by the present invention.

Claims

1. An adjustable water supply system with variable air gap height, provided on a lifting drilling platform, characterized in that: The lifting drilling platform comprises a main hull (1), a living roof (2), a cantilever beam drilling platform (3) and pile legs (4); The main hull (1) can be raised and lowered relative to the pile legs (4) to adjust the air gap height; The living building roof (2) is arranged on the upper side of one end of the main hull (1); The cantilever beam drilling platform (3) is arranged on the upper side of the other end of the main hull (1) and can slide horizontally relative to the main hull (1); The adjustable water supply system comprises a submersible pump (5), a cooling device assembly and a pipeline assembly; the cooling device assembly comprises a first cooling device (61) arranged on the roof of the living building; a second cooling device (62) and a third cooling device (63) arranged on the cantilever beam drilling platform (3); a fourth cooling device (64) and a fifth cooling device (65) arranged on the main hull (1); the submersible pump (5) and the cooling device assembly are connected via the pipeline assembly; The pipeline assembly comprises a first pipeline (71), a second pipeline (72) and a third pipeline (73); The first pipeline (71) connects the submersible pump (5) with the fourth cooling device (64) and the fifth cooling device (65) on the main hull (1); The second pipeline (72) is connected to the submersible pump (5) and the first cooling device (61) on the roof of the living building (2); The third pipeline (73) is in communication with the submersible pump (5) and the second cooling device (62) and the third cooling device (63) on the cantilever beam drilling platform (3); The inlet ends of the fourth cooling device (64) and the fifth cooling device (65) are provided with a first pressure gauge (81), and the outlet ends of the fourth cooling device (64) and the fifth cooling device (65) are provided with a first regulating valve (91) and a second regulating valve (92) respectively; the inlet end of the first cooling device (61) is provided with a second pressure gauge (82) and a third regulating valve (93); the outlet end of the first cooling device (61) is provided with a first seawater discharge port (10); the inlet ends of the second cooling device (62) and the third cooling device (63) are provided with a third pressure gauge (83), and the outlet ends are provided with a fourth regulating valve (94) and a fifth regulating valve (95) respectively; The pipeline assembly is provided with a plurality of regulating valves and pressure gauges, and the pressure in the pipeline assembly is detected by the pressure gauge, and then the opening and closing degree of the regulating valve is adjusted to achieve water supply regulation under different air gap heights; The height of the cantilever beam drilling platform (3) from the bottom of the ship is h3, and the height of the living building roof (2) from the bottom of the ship is h2, and the height h3 is greater than h2.

2. The adjustable water supply system according to claim 1, characterized in that: A sixth regulating valve (96) is provided at the junction of the outlet ends of the fourth cooling device (64) and the fifth cooling device (65); The sixth regulating valve (96) is connected to a second seawater discharge port provided at the bottom of the main hull (1), and a seventh regulating valve (97) is further provided between the sixth regulating valve (96) and the second seawater discharge port; An eighth regulating valve (98) is provided in the pipeline after the outlet ends of the second cooling device (62) and the third cooling device (63) are joined; the eighth regulating valve (98) is connected in sequence to the seventh regulating valve (97) and the second seawater discharge port.

3. The adjustable water supply system according to claim 1, characterized in that: The first pipeline (71) is a first hose (401) at the connection between the cantilever beam drilling platform (3) and the main hull (1); a return pipeline is provided at the outlet end of the second cooling device (62) and the third cooling device (63); the return pipeline is a second hose (402) at the connection between the cantilever beam drilling platform (3) and the main hull (1); and a fourth pressure gauge (84) is also provided at the outlet of the submersible pump (5).

4. A control method for an adjustable water supply system as claimed in claim 1, characterized in that: The following steps are involved: S1: Adjust the air gap height to the required air gap height, the maximum adjustable air gap height is h; S2: starting the submersible pump (5), gradually reducing the opening of the seventh regulating valve (97) from fully open, and adjusting the opening of the third regulating valve (93) to a range of 10% to 30%, until the outlet pressure of the submersible pump (5) is greater than the pressure converted from the potential energy of the highest cooling equipment component relative to the sea level; S3: adjusting the third regulating valve (93) on the second pipeline (72) so that the pressure detected by the second pressure gauge (82) is not greater than a threshold pressure set by the first cooling device (61); S4: regulating the sixth regulating valve (96) and the eighth regulating valve (98); so that the third pressure gauge (83) is at a positive pressure, and the pressure detected by the first pressure gauge (81) is not greater than the maximum threshold pressure allowed by the fourth cooling device (64) and the fifth cooling device (65); S5: simultaneously reducing the third regulating valve (93), the sixth regulating valve (96), and the seventh regulating valve (97); until the pressure detected by the third pressure gauge (83) meets the minimum required pressure of the second cooling device (62) and the third cooling device (63); and the pressure detected by the second pressure gauge (82) is not greater than the threshold pressure set for the first cooling device (61); S6: According to the demand for seawater by the second cooling device (62) and the third cooling device (63), the fourth regulating valve (94) and / or the fifth regulating valve (95) are adjusted, and the valve opening sizes are operated in reverse order to distribute the seawater demand of the two devices; according to the fourth cooling device (64) and the fifth cooling device (65), the first regulating valve (91) and / or the second regulating valve (92) are adjusted, and the valve opening sizes are operated in reverse order to distribute the seawater demand of the two devices.

5. The control method according to claim 4, characterized in that: When the operating height of the lifting drilling platform is higher than the standard air gap height h1, the opening of the seventh regulating valve (97) is reduced to increase the outlet pressure of the submersible pump (5) and reduce the total flow rate; when the operating height of the lifting drilling platform is lower than the standard air gap height h1, the opening of the seventh regulating valve (97) is increased to decrease the outlet pressure of the submersible pump (5) and increase the total flow rate.

6. The control method according to claim 5, characterized in that: The pipe size of the pipe assembly of the adjustable water supply system satisfies the formula ,in is the flow requirement of each pipeline, that is, the equipment flow requirement, is the flow velocity in the tube, and its value range is: .

7. The control method according to claim 4, characterized in that: The rated displacement of the submersible pump (5) The seawater cooling demand of each cooling equipment under drilling conditions The sum of , taking 20% ​​margin, satisfies the formula: ; Rated pressure Satisfy the formula: P B1 =ρg(h1+h3)+P0; where h1 is the standard air gap height, h3 is the height of the cantilever beam drilling platform (3) relative to the bottom of the ship, and P0 is 1~5 bar.

8. The control method according to claim 4, characterized in that: The opening of the regulating valve is R=0-1, wherein in step S2, the seventh regulating valve (97) is gradually adjusted down from R=1, wherein the opening of the third regulating valve (93) is adjusted to the interval of (0.1-0.3); until the fourth pressure gauge (84) measures the outlet pressure of the submersible pump (5) to be P2≥ρg(h1+h3), where ρ is the density of seawater, g is the acceleration of gravity, h1 is the air gap height, and h3 is the height from the drilling platform to the bottom of the ship.

9. The control method according to claim 4, characterized in that: The adjustable water supply system is adjusted within the maximum adjustable air gap height h, and the maximum adjustable air gap height h satisfies the following formula: ;in is the pipeline energy loss, P1 is the required pressure of the cantilever drilling platform (3); h max The pump operating point head height for regulating the pump flow rate of the jack-up drilling platform is limited to the maximum air gap h.

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