System and method for observing vertical section of seabed mud temperature in shallow sea area

Abstract

The invention discloses a system and a method for observing a vertical section of seabed mud temperature in a shallow sea area, and relates to the technical field of mud temperature observing.A mud temperature observation system is assembled on a deck of an ocean survey ship, the mud temperature observation system is lifted by a crane and slowly lowered, a PVC rod assembly firstly makes contact with seabed mud, a high-pressure flushing device is started, and high-pressure water impacts the seabed mud; and the underwater camera monitors the whole process, the mud temperature column is slowly pressed into the seabed mud, and after laying is completed, the mud temperature column measures the temperatures of the sea mud at different depths, and long-term measurement of the seabed mud temperature vertical section is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mud temperature observation, and in particular to an observation system and method for a vertical profile of seabed mud temperature in shallow sea areas. Background Art

[0002] The heat exchange between the sea and the air has been studied for a long time, and a large amount of long-term continuous observation data has been obtained, and a relatively mature parameterized model has been established. However, the heat exchange between seawater and seabed mud has been less studied, and there are few long-term continuous observations of seawater and sea mud temperature synchronization. Observational data in this area is urgently needed. Especially in the shallow waters of the continental shelf, the seawater temperature varies greatly with the seasons, and the temperature of the entire seawater layer changes accordingly, that is, the temperature of the seawater bottom layer that is in direct contact with the sea mud also changes dramatically, which is bound to cause a non-negligible heat exchange between the seawater and the sea mud.

[0003] Seabed mud temperature is an important seabed geophysical parameter and is of great significance to the study of marine corrosion. It is also a physical parameter that must be considered in marine engineering projects such as external heating of submarine oil pipelines, initial temperature setting for oil transportation, service life assessment of oil pipelines, and detection and exploitation of marine oil and natural gas.

[0004] However, in terms of ocean mud temperature measurement, there are few in-situ measurement data, even fewer long-term observation data (monthly and weekly), and almost no annual mud temperature observation data, resulting in a shallow understanding of seabed mud temperature in existing research. Therefore, it is urgent to carry out annual seabed mud temperature observations.

[0005] Most of China's coastal waters are shallow, and the seabed mud is mostly sandy and relatively soft. It is relatively easy to insert the device for measuring mud temperature into the sea mud at a certain depth to complete the measurement of mud temperature.

[0006] In the past, stainless steel was mostly used to measure the seabed mud temperature. The mud temperature measuring equipment was fixed in a stainless steel pipe or on the outside of the steel pipe to complete the mud temperature measurement. Steel has good thermal conductivity, and heat transfer is bound to occur during the measurement process, which affects the mud temperature measurement and makes the mud temperature measurement inaccurate, especially in long-term mud temperature observations. In order to improve the accuracy of mud temperature measurement, it is necessary to select insulating or extremely low thermal conductivity materials to replace stainless steel materials for mud temperature measurement, especially in long-term mud temperature observations. Summary of the invention

[0007] In order to solve the above problems, the present invention proposes an observation system for the vertical profile of seabed mud temperature in shallow sea areas, comprising: a mud temperature column, a high-pressure water flushing device, a real-time display terminal, and an underwater camera; The mud temperature column comprises: a PVC rod assembly and a self-contained mud temperature meter; the PVC rod assembly contacts the seabed mud, and the self-contained mud temperature meter is placed at different positions of the PVC rod assembly to measure the seabed mud temperature at different depths, thereby realizing long-term measurement of the vertical profile of the seabed mud; The underwater camera vertically monitors the mud temperature column downward and transmits the real-time picture to the real-time display terminal; The high-pressure water flushing device is used to form high-pressure water flushing from the bottom end of the mud temperature column to impact the seabed mud; In a preferred embodiment, the PVC rod assembly comprises: a PVC rod, a stainless steel cassette, and a stainless steel clasp; The PVC rod is bonded to the stainless steel pipe of the mud temperature column, and a stainless steel clamping ring slot, a self-contained mud temperature meter slot, a guide slot and a stainless steel cassette slot are provided on the PVC rod; The self-contained mud temperature meter slot is used to place the self-contained mud temperature meter, the stainless steel cassette slot is used to fix the stainless steel cassette, the stainless steel clamp ring slot is used to fix the stainless steel clamp ring, and the diversion groove is used to divert the seawater that impacts the sea mud with high pressure.

[0008] In a preferred embodiment, the PVC rod is provided with 7 self-contained mud temperature meter slots, so that the probes of the self-contained mud temperature meter are respectively located in the self-contained mud temperature meter slots at 0.0m, 0.5m, 1.0m, 1.5m, 2.0m, 2.5m, and 3.0m.

[0009] In a preferred embodiment, the observation system also includes a first weight block and a second weight block, a stainless steel clamping ring is fastened to the mud temperature column by bolts, and is connected to the first weight block by multiple U-shaped buckles; the second weight block is connected to the first weight block by multiple anchor chains, and the multiple U-shaped buckles are connected by shackles, and the second weight block has a hanging point and is connected to the multiple anchor chains by shackles.

[0010] In a preferred embodiment, the high-pressure water flushing device includes: a high-pressure water pump, a water inlet pipe, and a high-pressure water pipe; one end of the high-pressure water pump is connected to the water inlet pipe, and the other end is connected to the high-pressure water pipe, and the high-pressure water pipe is connected to the stainless steel pipe in the middle of the mud temperature column. The high-pressure water pipe introduces water into the stainless steel pipe in the middle of the mud temperature column, and high-pressure water flushing is formed from the bottom end of the mud temperature column to impact the sea mud on the seabed.

[0011] In a preferred embodiment, the PVC rod has a diameter of 12 cm, a length of 340 cm, and a conical lower end.

[0012] In a preferred embodiment, the self-contained mud temperature meter is powered by a lithium battery, has a sampling interval of 10 seconds, and a temperature measurement range of -5°C to 45°C.

[0013] The present invention also proposes an observation method for the vertical profile of seabed mud temperature in shallow sea areas, which is realized by the above-mentioned observation system. On the deck of an oceanographic survey ship, the mud temperature observation system is assembled, and the mud temperature observation system is slowly lowered by a crane. The PVC rod assembly first contacts the seabed mud, and the high-pressure water flushing device is started. The high-pressure water impacts the seabed mud and continues to be slowly lowered. An underwater camera monitors the entire process, and the mud temperature column is slowly pressed into the seabed mud. After the deployment is completed, the mud temperature column measures the sea mud temperature at different depths through self-contained mud temperature meters at different positions, thereby realizing long-term measurement of the vertical profile of the seabed mud temperature.

[0014] The present invention uses a PVC rod made of polyvinyl chloride (PVC) material with good thermal insulation performance as a carrier for mud temperature profile measurement, which has the following advantages: First, PVC rods have good thermal insulation properties, and the thermal conductivity of PVC rods is: 0.16 W / (m·K); in ocean observations, in order to minimize the corrosion of seawater to steel, stainless steel is generally used. The thermal conductivity of stainless steel is about 16 to 19 W / (m·K), which is a hundred times different from the previous one. In the ocean, the thermal conductivity of sea mud varies depending on the type of seabed mud, which is roughly around 1.0 W / (m·K); the thermal conductivity of seawater is 0.6-0.7 W / (m·K); from the above analysis, it can be seen that the thermal conductivity of PVC rods is extremely low. It can be seen that the use of PVC rod materials can greatly reduce the heat conduction caused by the mud temperature measurement device, thereby reducing the measurement error.

[0015] Second, PVC rods have stable physical and chemical properties and good salt resistance. They will not deform, become brittle, or corrode when immersed in sea mud. Their density is about 1.4g / cm 3 , the density of seawater is about 1.03g / cm 3 , greater than the density of sea water.

[0016] Third, PVC rods are cheap, easy to process, and widely used in the market.

[0017] Fourth, given that PVC rods have good thermal insulation and are easy to process, temperature measurement can be embedded in the PVC rods, which can reduce the resistance of the PVC rods inserted into the sea mud and facilitate offshore operations.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: Using PVC rods as the observation platform can greatly reduce the impact of heat conduction of the observation platform on mud temperature measurement and improve the accuracy of mud temperature measurement; A stainless steel pipe is embedded in the middle of the PVC rod, which increases the overall strength of the mud temperature column. It also leaves space for the installation of the self-contained mud temperature meter and makes the entire mud temperature column smoother and easier to insert into the sea mud. By using high-pressure water jets, it is easier to insert the mud temperature column into the sea mud, and the intensity of the high-pressure water jets can be adjusted to adapt to different seabed muds. The intensity of the high-pressure water jets can also be adjusted to allow the mud temperature column to be pressed deeper, so that the length of the mud temperature column can be increased to measure a deeper vertical profile of the mud temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall structural diagram of the observation method of the present invention; Figure 2 It is the structure diagram of mud temperature column; Figure 3 This is a schematic diagram of the mud temperature column after it is placed on the seabed; Figure 4 This is a schematic diagram of the second weight block and the stainless steel clamp ring; Figure 5 It is the vertical profile observation data of mud temperature. DETAILED DESCRIPTION

[0020] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 The figure shows the overall structure of the observation system for the vertical profile of seabed mud temperature in shallow waters.

[0022] The oceanographic survey vessel provides a supporting platform for the deployment and recovery of mud temperature columns.

[0023] One end of the high-pressure water pump is connected to the water inlet pipe, and the other end is connected to the high-pressure water pipe, which is then connected to the stainless steel pipe in the middle of the mud temperature column to form a high-pressure flushing device.

[0024] The stainless steel clamp is fastened to the mud temperature column by bolts and connected to the first weight block 1 by four U-shaped buckles. The second weight block 2 is connected to the first weight block 1 by four anchor chains with a specification of 8 mm, that is, connected to the above four U-shaped buckles by shackles, and the second weight block 2 has a hanging point and is connected to the four anchor chains by shackles.

[0025] The lifting cable of the oceanographic survey vessel is connected to four short steel cables, and the four short steel cables are connected to the four lifting points of the first weight 1 by shackles, so that the entire observation system can be lifted.

[0026] The camera end of the underwater camera is fixed on the lifting steel cable, which monitors the mud temperature column vertically downward, and the real-time image is transmitted to the real-time display terminal of the ocean survey ship.

[0027] The high-pressure water pump is used to extract seawater and generate high-pressure flushing water, which is introduced into the steel pipe in the middle of the mud temperature column by the high-pressure water pipe. High-pressure flushing water is formed from the bottom of the mud temperature column to impact the seabed mud, making the seabed mud soft. Under the pressure of the first weight block 1, the mud temperature column can slowly descend. As the depth of the mud temperature column inserted into the sea mud gradually increases, seawater flows out along the guide groove on the side of the mud temperature column and can carry the sea mud out. The mud temperature column can continue to descend until the mud temperature column is completely inserted into the sea mud and the deployment is completed.

[0028] It should be noted that the high-pressure water pump is used to extract seawater, and the process of generating high-pressure flushing water is as follows: the variable frequency motor is used to provide power, and the frequency of the variable frequency motor is adjusted to accurately control the water outlet pressure. In the process of impacting the sea mud, start with low water pressure, and gradually increase the frequency of the variable frequency motor according to the impact of the sea mud. When the appropriate water pressure is obtained, stop adjusting the motor frequency, and start to slowly press down the mud temperature column.

[0029] The underwater camera monitors the status of the mud temperature column and helps control the lowering speed when the lifting cable is lowered to ensure that the mud temperature column cannot tilt. It also monitors the lowering depth in real time. When the entire mud temperature column is pressed into the sea mud, the lowering is stopped and the high-pressure flushing is stopped.

[0030] The stainless steel clamp ring is fixed in the slot reserved in the mud temperature column and is tightly fixed on the mud temperature column. Firstly, when it is deployed, the mud temperature column can be slowly pressed into the sea mud under the pressure of the first weight block 1; secondly, during the observation process, the mud temperature column can be kept in place; thirdly, at the end of the observation, the entire mud temperature column can be slowly pulled out of the sea mud.

[0031] When the second weight block 2 is deployed, it falls to the seabed first, and then contacts the sea mud. It does not move, so it can keep the mud temperature column from swinging when pressing down the mud temperature column. It can stay in a fixed position even under the impact of high-pressure water and ensure that the mud temperature column is vertically pressed into the sea mud.

[0032] The mud temperature column is the key part of the whole mud temperature observation method, such as Figure 2 As shown, the mud temperature column consists of three parts: PVC rod assembly, stainless steel pipe, and self-contained mud temperature meter.

[0033] (1) PVC rod assembly The PVC rod assembly includes: a PVC rod, a stainless steel tape, and a stainless steel clamp ring.

[0034] First, make a whole PVC rod. During the production process, embed the stainless steel pipe in it. After the PVC material cools down, the PVC rod and the stainless steel pipe are bonded together to form a whole. Then make grooves on the PVC rod, including: stainless steel clamp ring groove, self-contained mud thermometer groove (two opposite sides of the PVC rod), guide groove and stainless steel cassette groove. Place the self-contained mud thermometer in the self-contained mud thermometer groove and fix it with a stainless steel cassette at the position of the stainless steel cassette groove. The lower end of the PVC is processed into a cone shape. Open two guide grooves on the other two opposite sides of the PVC rod.

[0035] PVC is the abbreviation of polyvinyl chloride. It has good thermal insulation and strong hardness, and can meet the requirements of sea mud temperature observation in muddy bottom sea areas.

[0036] Choose a PVC rod with a diameter of 12 cm and a length of 340 cm. The lower end of the PVC rod is processed into a cone shape to reduce the resistance when pressing down; the upper end of the PVC rod has a stainless steel clamp ring groove to fix the stainless steel clamp ring, so that the stainless steel clamp ring and the PVC rod are more firmly fixed together.

[0037] A groove is opened on the side of the PVC rod, and a self-contained mud temperature meter slot is provided. The depth of the groove is 3.0 cm and the length is 30 cm. The probe of the self-contained mud temperature measuring instrument can be fixed in the PVC rod. A stainless steel cassette slot is opened so that the stainless steel cassette falls into the slot, which can fix the self-contained mud temperature meter more firmly.

[0038] The PVC rod is equipped with 7 self-contained mud temperature meter slots, and the probes of the self-contained mud temperature meter are located at 0.0m, 0.5m, 1.0m, 1.5m, 2.0m, 2.5m, and 3.0m respectively. The number of layers can also be set according to the needs of the project. Slotting on the side of the PVC rod will inevitably affect the firmness of the PVC rod. In order to minimize the impact of slotting on the strength of the PVC rod, slots are made on both sides of the PVC rod. In addition to the slot for placing the self-contained mud temperature meter, diversion grooves are left on the other two sides of the PVC rod to divert the seawater that impacts the sea mud with high pressure. The probe part of the self-contained mud temperature meter is open to fully contact with the sea mud.

[0039] (2) Stainless steel pipe In the middle of the PVC rod, a stainless steel pipe is embedded with a diameter of 4cm and a wall thickness of 0.5cm. First, it can enhance the strength of the entire PVC rod and prevent it from breaking easily; second, it can be flushed with high pressure water to soften the sea mud and carry it away with the water flow, so that the mud temperature column can be pressed into the sea mud more easily. Silk patterns are processed on the upper end of the stainless steel pipe. After the mud temperature column is laid, the top of the stainless steel pipe is blocked to prevent the seawater and mud from flowing up and down.

[0040] (3) Self-contained mud temperature meter The self-contained mud temperature meter is preferably T to measure mud temperature. It is a self-contained temperature measurement device, powered by lithium batteries and automatically stored, with extremely low power consumption. It uses a sampling interval of 10s, and the power and storage are sufficient to complete annual observations. The temperature measurement accuracy is: 0.002℃, and the temperature measurement range is: -5℃ to 45℃. The mud temperature meter is 30cm long and 2.54cm in diameter.

[0041] The schematic diagram of the mud temperature column after it is placed on the seabed is as follows Figure 3 As shown. The mud temperature column is inserted vertically into the sea mud, and the insertion depth is about 3.1m. The second weight block 2 falls on the seabed interface, and the stainless steel clamp ring falls on the second weight block 2 and is fixed together with the second weight block 2. The stainless steel pipe is filled with sea mud, and the stainless steel pipe is sealed with a stainless steel pipe plugging cover to prevent the flow of sea mud inside the steel pipe. This mud temperature column can be placed on the seabed for a long time, and can measure the sea mud temperature at depths of 0.0m, 0.5m, 1.0m, 1.5m, 2.0m, 2.5m and 3.0m, completing the long-term measurement of the vertical profile of the seabed mud temperature.

[0042] The second weight 2 is made of lead material, which has a relatively high density of 11.3 g / cm 3 , which is 10 times the density of seawater, is used to stabilize the mud temperature column and is placed on the seabed. A 100 kg lead ring cake is made of lead material. The diameter of the inner ring in the middle is larger than the diameter of the mud temperature column, leaving space, and there are also 4 holes in the ring lead cake, so that the seawater on the seabed is fully in contact with the sea mud on the seabed, without affecting the mud temperature of the surface of the sea mud on the seabed, ensuring the accuracy of the mud temperature measurement.

[0043] The stainless steel clamp consists of two halves, which are tightly fixed to the mud temperature column with bolts and become one with the mud temperature column. It is convenient to hoist the mud temperature column when it is deployed. At the same time, it can withstand the pressure of the first weight block 1, so that the mud temperature column is slowly pressed into the sea mud. When recovering, the stainless steel clamp can be directly hoisted to lift the entire mud temperature column. The stainless steel clamp does not affect the contact between the seawater and the sea mud on the seabed.

[0044] Example 2 Offshore field observation operation process (1) The oceanographic survey ship arrives at the observation area and uses front and rear anchors to anchor the ship. During the entire deployment process of the mud temperature observation system, the ship's position must be kept fixed; (2) The oceanographic survey vessel is equipped with a crane with a lifting capacity of more than 500 kg. The crane boom can lift objects up to 4 meters high and can be extended beyond the hull.

[0045] (3) On the deck of the oceanographic survey ship, assemble the mud temperature observation system, lift the entire device with a crane, and place it outside the hull, then slowly lower it, with the PVC rod assembly first contacting the sea mud on the seabed. Then start the high-pressure water flushing device, and the high-pressure water will impact the sea mud on the seabed. At the same time, continue to slowly lower it, and the mud temperature column will slowly press into the sea mud on the seabed. During the lowering process, the underwater camera monitors the entire process to ensure that the deployment process is completed smoothly. Then the diver goes into the water, unfastens the connecting buckle between the first weight block 1 and the stainless steel clamp ring, recycles the first weight block 1 to the deck, and connects the second weight block 2 to the stainless steel clamp ring. The entire deployment work is completed.

[0046] Field observation data in the sea area Using this observation method in a specific sea area, a one-month vertical profile observation of mud temperature was carried out from November 22, 2023 to December 22, 2023. Mud temperature data at depths of 0.0m, 0.5m, 1.0m, 0.5m, 2.0m, 2.5m and 3.0m were obtained. The observation data are as follows Figure 5 shown.

[0047] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. The embodiments should therefore be considered exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An observation system for the vertical profile of seabed mud temperature in shallow sea areas, characterized in that: include: Mud temperature column, high-pressure water flushing device, real-time display terminal, underwater camera; The mud temperature column comprises: a PVC rod assembly and a self-contained mud temperature meter; The PVC rod assembly contacts the seabed mud, and the self-contained mud temperature meter is placed at different positions of the PVC rod assembly to measure the seabed mud temperature at different depths, thereby realizing long-term measurement of the vertical profile of the seabed mud; The underwater camera vertically monitors the mud temperature column downward and transmits the real-time picture to the real-time display terminal; The high-pressure water flushing device is used to form high-pressure water flushing from the bottom end of the mud temperature column to impact the seabed mud.

2. The shallow sea area seabed mud temperature vertical profile observation system according to claim 1 is characterized in that: The PVC rod assembly comprises: a PVC rod, a stainless steel cassette, and a stainless steel clasp; The PVC rod is bonded to the stainless steel pipe of the mud temperature column, and a stainless steel clamping ring slot, a self-contained mud temperature meter slot, a guide slot and a stainless steel cassette slot are provided on the PVC rod; The self-contained mud temperature meter slot is used to place the self-contained mud temperature meter, the stainless steel cassette slot is used to fix the stainless steel cassette, the stainless steel clamp ring slot is used to fix the stainless steel clamp ring, and the diversion groove is used to divert the seawater that impacts the sea mud with high pressure.

3. The shallow sea area seabed mud temperature vertical profile observation system according to claim 2 is characterized in that: The PVC rod is provided with 7 self-contained mud temperature meter slots, so that the probes of the self-contained mud temperature meter are respectively located in the self-contained mud temperature meter slots at 0.0m, 0.5m, 1.0m, 1.5m, 2.0m, 2.5m and 3.0m.

4. The shallow sea area seabed mud temperature vertical profile observation system according to claim 1, characterized in that: The observation system also includes a first weight block and a second weight block. The stainless steel clamp is fastened to the mud temperature column by bolts and is connected to the first weight block by multiple U-shaped buckles. The second weight block is connected to the first weight block by multiple anchor chains, and the multiple U-shaped buckles are connected by shackles. The second weight block has a hanging point and is connected to the multiple anchor chains by shackles.

5. The shallow sea area seabed mud temperature vertical profile observation system according to claim 1, characterized in that: The high-pressure water flushing device includes: a high-pressure water pump, a water inlet pipe, and a high-pressure water pipe; one end of the high-pressure water pump is connected to the water inlet pipe, and the other end is connected to the high-pressure water pipe, and the high-pressure water pipe is connected to the stainless steel pipe in the middle of the mud temperature column. The high-pressure water pipe introduces water into the stainless steel pipe in the middle of the mud temperature column, and high-pressure water flushing is formed from the bottom end of the mud temperature column to impact the sea mud on the seabed.

6. The shallow sea area seabed mud temperature vertical profile observation system according to claim 2, characterized in that: The PVC rod has a diameter of 12 cm, a length of 340 cm, and a conical lower end.

7. The shallow sea area seabed mud temperature vertical profile observation system according to claim 2, characterized in that: The self-contained mud temperature meter is powered by a lithium battery, has a sampling interval of 10 seconds, and a temperature measurement range of -5°C to 45°C.

8. A method for observing the vertical profile of seabed mud temperature in shallow waters, implemented by the observation system according to any one of claims 1 to 7, characterized in that: On the deck of the oceanographic survey ship, the mud temperature observation system is assembled and then lifted by a crane and slowly lowered. The PVC rod assembly first contacts the sea mud on the seabed, and the high-pressure water flushing device is started. The high-pressure water impacts the sea mud on the seabed and continues to be slowly lowered. The underwater camera monitors the entire process. The mud temperature column is slowly pressed into the sea mud on the seabed. After the deployment is completed, the mud temperature column measures the sea mud temperature at different depths through self-contained mud thermometers at different positions, thereby realizing long-term measurement of the vertical profile of the seabed mud temperature.

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