A low-temperature mousehole on the drill floor for segmental disassembly of a pressure-holding core barrel

Abstract

The present invention discloses a low-temperature mousehole on the drill floor for segmental disassembly of a pressure-maintaining corer, which is installed on the drill floor and includes an outer cylinder, an intermediate cylinder and an inner cylinder that are sequentially sleeved from the outside to the inside and support and fix each other; a sealed annular space is formed between the outer cylinder and the intermediate cylinder; the annular space between the inner cylinder and the intermediate cylinder forms a closed annular passage, and the annular passage is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the outlet of an external circulation machine through a pipeline, and the liquid outlet is connected to the inlet of the external circulation machine through a pipeline; a circulation passage for the coolant is formed between the annular passage and the external circulation machine; after the pressure-maintaining corer is salvaged from the subsea coring rope to the drill floor, it is directly vertically hoisted and placed into the inner cylinder for rapid segmental disassembly. This device realizes the hoisting and heat-insulating disassembly of the pressure-maintaining corer on the drill floor through water-cooled circulation refrigeration and heat preservation, avoids heat transfer with the atmospheric environment during the disassembly process, meets the environmental requirements of high pressure and low temperature, and ensures that the hydrate in the pressure-maintaining corer does not decompose.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore drilling equipment, and particularly relates to a low-temperature mousehole on the drill floor for segmented disassembly of a pressure-maintaining corer. Background Art

[0002] The pressure-maintaining coring of natural gas hydrate solves the problem of hydrate decomposition caused by temperature and pressure changes during the coring process. During the operation of pressure-maintaining coring, after coring in the well is completed, it is salvaged to the drill floor by a wireline for disassembly operation. When the pressure-maintaining corer exits the wellhead on the drill floor, if the disassembly time is too long, the high temperature in the air will transfer heat to the hydrate inside the pressure-maintaining corer. At this time, if the temperature is too high, it will cause the hydrate inside the pressure-maintaining corer to decompose, resulting in a sharp increase in the pressure inside the pressure-maintaining corer and affecting the operation safety. Summary of the Invention

[0003] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a low-temperature mousehole on the drill floor for segmented disassembly of a pressure-maintaining corer.

[0004] The present invention is realized by the following technical solutions: A low-temperature mousehole on the drill floor for segmented disassembly of a pressure-maintaining corer is vertically installed on the drill floor and includes an outer cylinder, an intermediate cylinder, and an inner cylinder that are sequentially sleeved from the outside to the inside and support and fix each other; a sealed annular space is formed between the outer cylinder and the intermediate cylinder; an enclosed annular passage is formed by the annular space between the inner cylinder and the intermediate cylinder, and the annular passage is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the outlet of an external circulation machine through a pipeline, and the liquid outlet is connected to the inlet of the external circulation machine through a pipeline; a circulation passage for the coolant is formed between the annular passage and the external circulation machine; after the pressure-maintaining corer is salvaged from the subsea coring wireline to the drill floor, it is directly vertically hoisted and placed into the inner cylinder for segmented rapid disassembly.

[0005] A circulation passage is formed between the annular passage and the external circulation machine. The coolant in the external circulation machine flows in the circulation passage and circulates in the annular passage to cool the inner cylinder, maintaining a low-temperature environment in the inner cylinder to meet the environmental preservation requirements of high pressure and low temperature for the hydrate inside the pressure-maintaining corer, ensuring that the hydrate inside the pressure-maintaining corer does not decompose, and thus ensuring the installation and disassembly operation requirements of the pressure-maintaining corer.

[0006] The annular space between the outer cylinder and the intermediate cylinder is filled with a heat-insulating layer, and the heat-insulating layer covers the outer side wall and the bottom of the intermediate cylinder. The setting of the heat-insulating layer can prevent heat loss during the coolant circulation refrigeration process of the annular passage, affecting the refrigeration effect. Covering the outer side wall and the bottom of the intermediate cylinder with the heat-insulating layer can ensure the heat-insulating effect.

[0007] The liquid inlet is connected to a liquid injection pipeline, and the liquid injection pipeline is located within the annulus channel; the outlet of the liquid injection pipeline is located at the center of the bottom of the annulus channel and on the bottom side of the inner cylinder; the liquid outlet is located at the upper part of the middle cylinder and below the liquid inlet. The outlet of the liquid infusion pipeline is the actual liquid inlet. This structure has a low liquid inlet and a high liquid outlet, and the liquid exchanges heat from bottom to top, which can meet the requirement of the cooling liquid flowing evenly in a circulating refrigeration manner from the bottom to the top of the annulus channel. Thus, the heat transfer of the cooling liquid is more persistent, the cooling effect of the inner cylinder is better, and the utilization rate of the cooling liquid is higher.

[0008] A structural load-bearing ring that surrounds the outer circumference of the inner cylinder is sleeved on the outer circumference of the inner cylinder. The outer end of the structural load-bearing ring abuts against the inner wall of the middle cylinder, and the inner cylinder is suspended inside the middle cylinder; the structural load-bearing ring is provided with mounting holes, and the liquid injection pipeline is threaded through the mounting holes. The structural load-bearing ring bears the weight of the inner cylinder, enabling the inner cylinder to be suspended inside the middle cylinder. The setting of the mounting holes is used to fix the liquid injection pipeline.

[0009] A reinforcing rib that surrounds the outer circumference of the middle cylinder is sleeved on the outer circumference of the middle cylinder. The inner end of the reinforcing rib is fixed to the inner side wall of the outer cylinder, and the outer end of the reinforcing rib is fixed to the outer wall surface of the middle cylinder.

[0010] The middle cylinder is also connected to an annular water outlet connecting pipe that surrounds half of the outer circumference of the upper part of the middle cylinder. The inlet of the annular water outlet connecting pipe communicates with the upper part of the middle cylinder, and its outlet communicates with the liquid outlet. The outlet of the annular water outlet connecting pipe communicates with the liquid outlet, forming two outlets, so that the cooling liquid can flow dispersedly and evenly, enhancing the uniform cooling effect.

[0011] A load-bearing plate is installed on the outer circumference of the top of the inner cylinder. The inner side of the load-bearing plate is fixed to the outer wall of the inner cylinder, the top end of the middle cylinder is fixed on the load-bearing plate, and the load-bearing plate seals the annulus channel and forms a sealed gap.

[0012] The structural load-bearing ring is provided with at least three circles, which are respectively the upper section, middle section, and lower section of the outer circumference of the inner cylinder. The structural load-bearing ring having at least three circles can make the support between the inner cylinder and the middle cylinder stable.

[0013] A number of the reinforcing ribs are provided, and the number of the reinforcing ribs is evenly sleeved on the outer circumference of the middle cylinder. Having a number of reinforcing ribs can provide stable support between the middle cylinder and the outer cylinder.

[0014] A load-bearing seat is sleeved on the outer periphery of the outer cylinder, and a lifting lug is arranged on the load-bearing seat; the lower half of the pressure-holding corer is a high-pressure sealing chamber. When the rope fishing operation is completed and the high-pressure sealing chamber is hoisted and lowered into the inner cylinder when the rope is fished to the drill floor, the upper half of the pressure-holding corer is exposed outside the inner cylinder. The load-bearing seat is used to support the overall weight of the entire low-temperature mousehole on the drill floor, and the lifting lug can be used by a lifting tool to lift the entire device. The upper half of the pressure-holding corer is exposed outside the inner cylinder, which can meet the disassembly requirements and avoid the thermal decomposition of the hydrate core during the disassembly process.

[0015] Compared with the prior art, the advantages of the present invention are as follows: Through water-cooled circulation refrigeration and heat preservation, the pressure-holding corer can be hoisted on the drill floor and disassembled in sections with heat preservation, avoiding heat transfer between the high-pressure sealing chamber of the pressure-holding corer and the atmospheric environment during the disassembly process, so as to meet the environmental requirements of high pressure and low temperature of the hydrate in the pressure-holding corer and ensure that the hydrate in the pressure-holding corer does not decompose. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0017] Figure 2 It is a schematic structural diagram of the embodiment of the present invention being lifted by a sling;

[0018] Figure 3 It is a schematic structural diagram of the embodiment of the present invention installed on the drill floor deck;

[0019] Figure 4 It is a schematic structural diagram of the embodiment of the present invention when loaded into the pressure-holding corer.

[0020] The meanings of the reference numerals in the drawings: 1. Outer cylinder; 2. Intermediate cylinder; 3. Inner cylinder; 4. Annular channel; 5. Liquid inlet; 6. Liquid outlet; 7. External circulation machine; 8. Heat preservation layer; 9. Liquid injection pipeline; 10. Structural load-bearing ring; 11. Installation hole; 12. Reinforcing rib; 13. Annular water outlet connecting pipe; 14. Load-bearing plate; 15. Load-bearing seat; 16. Lifting lug; 17. Drill floor deck; 18. Moonpool; 19. Pressure-holding corer; 20. High-pressure sealing chamber; 21. Hydrate core; 22. Sling. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following further describes the content of the present invention in detail in conjunction with the drawings and specific embodiments.

[0022] Embodiment

[0023] Refer to Figures 1 to 4, is a low-temperature mousehole on the drill floor for segmental disassembly of a pressure-maintaining corer, vertically installed on the drill floor, including an outer cylinder 1, an intermediate cylinder 2, and an inner cylinder 3 that are sequentially sleeved from the outside to the inside and support and fix each other; a sealed annular gap is formed between the outer cylinder 1 and the intermediate cylinder 2; the annular gap between the inner cylinder 3 and the intermediate cylinder 2 forms a sealed annular passage 4, and the annular passage 4 is provided with a liquid inlet 5 and a liquid outlet 6. The liquid inlet 5 is connected to the outlet of an external circulation machine 7 through a pipeline, and the liquid outlet 6 is connected to the inlet of the external circulation machine 7 through a pipeline; a circulation passage for the coolant is formed between the annular passage 4 and the external circulation machine 7; after the pressure-maintaining corer 19 is salvaged from the subsea coring rope on the drill floor, it is directly vertically hoisted and placed into the inner cylinder 3 for rapid segmental disassembly.

[0024] A circulation passage is formed between the annular passage 4 and the external circulation machine 7. The coolant in the external circulation machine 7 flows in the circulation passage and circulates in the annular passage 4 to cool the inner cylinder 3 and maintain a low-temperature environment in the inner cylinder 3 to meet the requirements for the high-pressure and low-temperature environmental preservation of hydrates inside the pressure-maintaining corer 19, ensuring that the hydrates inside the pressure-maintaining corer 19 do not decompose, thereby guaranteeing the installation and disassembly operation requirements of the pressure-maintaining corer 19.

[0025] The annular gap between the outer cylinder 1 and the intermediate cylinder 2 is filled with a heat-insulating layer 8, and the heat-insulating layer 8 covers the outer side wall and the bottom of the intermediate cylinder 2. The setting of the heat-insulating layer 8 can prevent heat loss during the coolant circulation refrigeration process of the annular passage 4 and affect the refrigeration effect. The heat-insulating layer 8 covering the outer side wall and the bottom of the intermediate cylinder 2 can ensure the heat-insulating effect.

[0026] The liquid inlet 5 is connected to a liquid injection pipeline 9, and the liquid injection pipeline 9 is located inside the annular passage 4; the outlet of the liquid injection pipeline 9 is located at the center of the bottom of the annular passage 4 and is on the bottom side of the inner cylinder 3; the liquid outlet 6 is located in the upper part of the intermediate cylinder 2 and is below the liquid inlet 5. The outlet of the infusion pipeline is the actual liquid inlet. This structure is for low-position liquid inlet and high-position liquid outlet, and the liquid exchanges heat from bottom to top, which can meet the requirement of uniform upward circulation refrigeration of the coolant in the annular passage 4 from the bottom, so that the heat transfer of the coolant is more persistent, the cooling effect of the inner cylinder 3 can be better, and the utilization rate of the coolant is higher.

[0027] A structural load-bearing ring 10 that surrounds the outer circumference of the inner cylinder 3 is sleeved on the outer circumference of the inner cylinder 3. The outer end of the structural load-bearing ring 10 abuts against the inner wall of the intermediate cylinder 2, and the inner cylinder 3 is suspended inside the intermediate cylinder 2; the structural load-bearing ring 10 is provided with an installation hole 11, and the liquid injection pipeline 9 is inserted into the installation hole 11. The structural load-bearing ring 10 bears the weight of the inner cylinder 3, enabling the inner cylinder 3 to be suspended inside the intermediate cylinder 2. The setting of the installation hole 11 is used to fix the liquid injection pipeline 9.

[0028] A reinforcing rib 12 that surrounds the outer circumference of the intermediate cylinder 2 is sleeved on the outer circumference of the intermediate cylinder 2. The inner end of the reinforcing rib 12 is fixed to the inner side wall of the outer cylinder 1, and the outer end of the reinforcing rib 12 is fixed to the outer wall surface of the intermediate cylinder 2.

[0029] The middle cylinder 2 is also connected with an annular water outlet connecting pipe 13 that surrounds the outer circumference of the upper part of the middle cylinder 2 for half a circle. The inlet of the annular water outlet connecting pipe 13 is communicated with the upper part of the middle cylinder 2, and its outlet is communicated with the liquid outlet 6. The outlet of the annular water outlet connecting pipe 13 is communicated with the liquid outlet 6, forming two outlets, so that the coolant can flow dispersedly and evenly, enhancing the uniform cooling effect.

[0030] A load-bearing plate 14 is installed on the outer circumference of the top of the inner cylinder 3. The inner side of the load-bearing plate 14 is fixed on the outer wall of the inner cylinder 3. The top end of the middle cylinder 2 is fixed on the load-bearing plate 14. The load-bearing plate 14 seals the annular empty channel 4 and forms a sealed gap.

[0031] The structural load-bearing rings 10 are provided with at least three circles, which are respectively located at the upper, middle and lower segments of the outer circumference of the inner cylinder 3. Having at least three circles of the structural load-bearing rings 10 can make the support between the inner cylinder 3 and the middle cylinder 2 stable.

[0032] A number of reinforcing ribs 12 are provided. The number of reinforcing ribs 12 is evenly sleeved on the outer circumference of the middle cylinder 2. Having a plurality of reinforcing ribs 12 can make the support between the middle cylinder 2 and the outer cylinder 1 stable.

[0033] A load-bearing seat 15 is sleeved on the outer circumference of the outer cylinder 1, and a lifting lug 16 is provided on the load-bearing seat 15; the lower half of the pressure-retaining corer 19 is a high-pressure sealed chamber 20. When the pressure-retaining coring operation for a round trip is completed and the wireline is fished to the drill floor, the high-pressure sealed chamber 20 is hoisted and lowered into the inner cylinder 1, and the upper half of the pressure-retaining corer 19 is exposed outside the inner cylinder 1. The load-bearing seat 15 is used to support the overall weight of the entire drill floor low-temperature mousehole, and the lifting lug 16 can be used by a lifting tool to lift the entire device. The upper half of the pressure-retaining corer 19 is exposed outside the inner cylinder 1, which can meet the disassembly requirements and avoid the thermal decomposition of the hydrate core 21 during the disassembly process.

[0034] In this embodiment, the drill floor low-temperature mousehole for the segmented disassembly of the pressure-retaining corer 19 is installed within the moonpool 18 of the drill floor deck 17. After the pressure-retaining corer 19 is fished from the seabed to the drill floor, it is hoisted into the inner cylinder 3 through a sling 22 for operation and disassembly. The pressure-retaining corer 19 containing the hydrate core 21 is inserted into the inner cylinder 3 for the pressure-retaining corer 19 to be disassembled therein. The pressure-retaining corer 19 has a high-pressure sealed chamber 20 inside, and the hydrate core 21 is loaded in the high-pressure sealed chamber 20.

[0035] The above detailed description is for the specific description of the feasible embodiments of the present invention. These embodiments are not intended to limit the patent scope of the present invention. Any equivalent implementation or modification without departing from the present invention should be included in the patent scope of this case.

Claims

1. A low-temperature mousehole on the drill floor for segmented disassembly of a pressure-maintaining corer, vertically installed on the drill floor, characterized in that: It includes an outer cylinder, an intermediate cylinder, and an inner cylinder that are sleeved from outside to inside in sequence and achieve mutual support and fixation; a sealed annular gap is formed between the outer cylinder and the intermediate cylinder; the annular gap between the inner cylinder and the intermediate cylinder forms a sealed annular passage. The annular passage is provided with a liquid inlet and a liquid outlet. The liquid inlet is connected to the outlet of an external circulation machine through a pipeline, and the liquid outlet is connected to the inlet of the external circulation machine through a pipeline; a circulation passage for the coolant is formed between the annular passage and the external circulation machine; after the pressure-maintaining corer is salvaged from the subsea coring rope to the drill floor, it is directly vertically hoisted and placed into the inner cylinder for segmented and rapid disassembly; the liquid inlet is connected to a liquid injection pipeline, and the liquid injection pipeline is located in the annular passage; the outlet of the liquid injection pipeline is located at the center of the bottom of the annular passage and at the bottom side of the inner cylinder; the liquid outlet is located at the upper part of the intermediate cylinder and below the liquid inlet; an outer peripheral structure load-bearing ring that surrounds the outer periphery of the inner cylinder in a circle is sleeved on the outer periphery of the inner cylinder. The outer end of the structure load-bearing ring abuts against the inner wall of the intermediate cylinder, and the inner cylinder is suspended inside the intermediate cylinder; the structure load-bearing ring is provided with mounting holes, and the liquid injection pipeline is inserted through the mounting holes.

2. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-holding corer according to claim 1, characterized in that: The annular gap between the outer cylinder and the intermediate cylinder is filled with a heat-insulating layer, and the heat-insulating layer covers the outer side wall and the bottom of the intermediate cylinder.

3. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-maintaining corer according to claim 1, characterized in that: Reinforcing ribs that surround the outer periphery of the intermediate cylinder in a circle are sleeved on the outer periphery of the intermediate cylinder. The inner ends of the reinforcing ribs are fixed to the inner side wall of the outer cylinder, and the outer ends of the reinforcing ribs are fixed to the outer wall surface of the intermediate cylinder.

4. The low-temperature mousehole on the drill floor for sectional disassembly of the pressure-holding corer according to claim 1, characterized in that: The intermediate cylinder is further connected to an annular water outlet connecting pipe that surrounds the upper outer periphery of the intermediate cylinder for half a circle. The inlet of the annular water outlet connecting pipe communicates with the upper part of the intermediate cylinder, and its outlet communicates with the liquid outlet.

5. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-maintaining corer according to claim 1, wherein: A load-bearing plate is installed on the outer periphery of the top of the inner cylinder. The inner side of the load-bearing plate is fixed to the outer wall of the inner cylinder. The top end of the intermediate cylinder is fixed on the load-bearing plate, and the load-bearing plate seals the annular passage and forms a sealed gap.

6. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-maintaining corer according to claim 1, characterized in that: There are at least three circles of the structure load-bearing rings, which are respectively located at the upper, middle, and lower segments of the outer periphery of the inner cylinder.

7. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-holding corer according to claim 3, characterized in that: A number of the reinforcing ribs are provided, and the number of the reinforcing ribs are evenly sleeved on the outer periphery of the intermediate cylinder.

8. The low-temperature mousehole on the drill floor for segmented disassembly of the pressure-holding corer according to claim 1, characterized in that: A load-bearing seat is sleeved on the outer periphery of the outer cylinder, and lifting lugs are provided on the load-bearing seat; the lower half of the pressure-maintaining corer is a high-pressure sealed chamber. When the pressure-maintaining coring operation for a round trip is completed and the rope is salvaged to the drill floor, the high-pressure sealed chamber is hoisted and lowered into the inner cylinder, and the upper half of the pressure-maintaining corer is exposed outside the inner cylinder.

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