An in-situ freezing-salting-out film-forming simulation device for gas hydrate while drilling

Abstract

The present invention belongs to the technical field of coring simulation devices, and particularly relates to an in-situ freezing-salting out film-forming simulation device for combustible ice during drilling. The simulation device of the present invention includes a deep-sea environment simulation chamber. Inside the deep-sea environment simulation chamber, there is a stroke piston and an outer coring drill which are connected to each other. An inner coring barrel is sleeved inside the outer coring drill. The inner coring barrel is rotationally connected to the stroke piston. A center rod bottom piston is sleeved inside the inner coring barrel. A center rod is connected to the center rod bottom piston. The center rod extends out of the inner coring barrel, the stroke piston, and the deep-sea environment simulation chamber. A liquid supply cavity is arranged inside the outer coring drill. The inner coring barrel is provided with inner coring barrel mesh holes. Before the liquid supply cavity is communicated with the inner coring barrel mesh holes after coring is completed, a liquid cold source is injected into the liquid supply cavity. When the inner coring barrel rotates to make the inner coring barrel mesh holes communicate with the liquid supply cavity, a salting-out liquid is injected into the liquid supply cavity. The present invention provides a coring device that couples the freezing-salting out film-forming principle of the film-forming liquid and can simulate the in-situ film-forming process during deep-sea drilling.

Description

Technical Field

[0001] The present invention belongs to the technical field of coring simulation devices, and particularly relates to a simulation device for in-situ freezing-salting out and film-forming while drilling for combustible ice. Background Art

[0002] Obtaining accurate material information within in-situ combustible ice samples has great scientific significance, and can provide guidance for the accurate exploration and evaluation of combustible ice reservoirs, and the research on the origin and migration law of alkanes by submarine microorganisms. However, the existing submarine sediment coring technology does not consider taking protective measures for the core. The core directly contacts the external environment, and it is difficult to avoid the diffusion and loss of substances in the core pores, which will lead to the distortion of the core analysis results and the extinction of the original microorganisms, and it is even more impossible to study the mysteries of submarine life science. Therefore, it is necessary to develop an in-situ film-forming and quality-preserving coring technology for combustible ice while drilling. By uniformly growing a dense polymer solid film with high barrier performance on the surface of the combustible ice core during the dynamic process of drilling, this layer of film can preserve the volatile alkane components in the combustible ice core, maintain the humidity stability inside the core and the in-situ dark and lightless environment, so as to truly obtain a core sample that preserves the true state of the seabed in-situ. Summary of the Invention

[0003] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a coring device that couples the film-forming principle of freezing-salting out of the film-forming liquid and can simulate the in-situ film-forming process while drilling in the deep sea.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A simulation device for in-situ freezing-salting out and film-forming while drilling for combustible ice, including a deep-sea environment simulation chamber. Inside the deep-sea environment simulation chamber, there is a stroke piston and an outer coring drill connected to each other. Inside the outer coring drill, there is a coring barrel sleeved. The coring barrel is rotationally connected to the stroke piston. Inside the coring barrel, there is a bottom piston of the central rod sleeved. The bottom piston of the central rod is connected with a central rod, and the central rod extends out of the coring barrel, the stroke piston and the deep-sea environment simulation chamber; a liquid supply cavity is arranged inside the outer coring drill, and the coring barrel is provided with coring barrel mesh holes. Before the liquid supply cavity is communicated with the coring barrel mesh holes after coring is completed, a liquid cold source is injected into the liquid supply cavity. When the coring barrel rotates to make the coring barrel mesh holes communicate with the liquid supply cavity, a salting-out liquid is injected into the liquid supply cavity.

[0006] The coring part is integrally hoisted above the seawater cavity through the central rod. By pumping seawater into the seawater cavity, the air is discharged from the seawater cavity outlet, so that the whole coring device is immersed in seawater to simulate the in-situ water environment in the deep sea. Using a high-pressure pump to continuously pump seawater into the seawater cavity to increase the pressure in the seawater cavity and simulate the high-pressure environment in the deep sea. By injecting a cold source liquid into the coolant cavity of the deep-sea environment simulation chamber, the temperature of the seawater in the seawater cavity is reduced to simulate the in-situ low-temperature environment of deep-sea combustible ice.

[0007] During coring, the central rod remains stationary. By pumping hydraulic oil, the stroke piston is pushed, further driving the core barrel and the outer coring drill downwards as a whole to drill the core. A relative movement occurs between the central rod and the core barrel, reducing the volume of the film-forming liquid cavity, and the film-forming liquid gradually displaces seawater in-situ to cover the surface of the core.

[0008] After the core completely enters the core barrel, a liquid cold source is injected into the liquid supply cavity of the outer coring drill. After the cold source circulates for a period of time, the film-forming liquid gradually undergoes a phase change reaction to form a solid film layer. The core barrel is rotated to connect the liquid supply cavity with the mesh holes of the core barrel, and then a salting-out liquid is injected into the liquid supply cavity of the outer coring drill. When the salting-out liquid contacts the solidified film, ions gradually diffuse into the film material, producing a salting-out effect, enhancing the barrier performance and mechanical properties of the film-forming liquid, and improving the preservation efficiency. Finally, a high-performance solid sealing film layer is simulated and generated in the low-temperature and high-pressure water environment reconstructed in the deep sea, and the original material information in the core is stored for a long time.

[0009] The present invention can realize the technological process of reconstructing the in-situ high-pressure and low-temperature environment in the deep sea, simulating the dynamic release of the film-forming liquid during drilling, and forming a solid sealing film layer on the surface of the core. The present invention couples the film-forming principle of freezing-salting-out of the film-forming liquid to rapidly form a solid sealing film with high barrier performance on the surface of the core during the coring process. The simulation device can inject the cold source and the salting-out liquid into the core sampler from the outside step by step by constructing a circulation channel, respectively realizing the freezing and salting-out functions, and has practicability in actual coring projects, providing a stable and efficient feasible solution for the implementation of the in-situ film-forming project of combustible ice during drilling.

[0010] As a preferred embodiment of the present invention, the liquid supply cavity includes an inlet flow channel of the outer coring drill, an outlet flow channel of the outer coring drill, and an annular flow channel of the outer coring drill. The inlet flow channel of the outer coring drill and the outlet flow channel of the outer coring drill are arranged on the circumferential surface of the outer coring drill, and the annular flow channel of the outer coring drill is arranged at the bottom of the outer coring drill. The annular flow channel of the outer coring drill is respectively communicated with the inlet flow channel of the outer coring drill and the outlet flow channel of the outer coring drill; mesh holes of the outer coring drill are arranged on the inner wall of the outer coring drill. When the mesh holes of the core barrel are aligned with the mesh holes of the outer coring drill, the inlet flow channel of the outer coring drill and the outlet flow channel of the outer coring drill are respectively communicated with the core barrel.

[0011] When a liquid cold source is introduced into the inlet flow channel of the outer coring drill, the liquid cold source enters the outlet flow channel of the outer coring drill through the annular flow channel of the outer coring drill, so that the liquid cold source can flow through all circumferential regions of the outer coring drill, ensuring that the film-forming liquid on the surface of the core is evenly cooled, and thus the film-forming liquid gradually undergoes a phase change reaction to form a solid film layer. When the mesh holes of the core barrel are aligned with the mesh holes of the outer coring drill, a salting-out liquid is injected into the outer coring drill. The salting-out liquid enters the core barrel through the inlet flow channel of the outer coring drill, the mesh holes of the outer coring drill, and the mesh holes of the core barrel. When the salting-out liquid contacts the solidified film, ions gradually diffuse into the film material, producing a salting-out effect, enhancing the barrier performance and mechanical properties of the film-forming liquid, and improving the preservation efficiency.

[0012] As a preferred embodiment of the present invention, a core barrel limiting key is provided on the outer wall of the core barrel, and a core barrel outer drill limiting key groove for limiting the core barrel limiting key is provided on the inner wall of the core barrel outer drill. In the initial state, there is an angular misalignment of 30° between the core barrel outer drill mesh holes and the core barrel mesh holes. When the core barrel is rotated, the core barrel outer drill limiting key groove limits the core barrel limiting key, and at this time, the core barrel outer drill mesh holes and the core barrel mesh holes are aligned, allowing the medium to flow through.

[0013] As a preferred embodiment of the present invention, a core barrel inlet flow channel and a core barrel outlet flow channel are provided at the upper end of the core barrel. The core barrel inlet flow channel is communicated with the core barrel outer drill inlet flow channel, and the core barrel outlet flow channel is communicated with the core barrel outer drill outlet flow channel; a central rod inlet flow channel and a central rod outlet flow channel are provided on the central rod. After the piston at the bottom of the central rod reaches the inner top of the core barrel, the central rod inlet flow channel is communicated with the core barrel inlet flow channel, and the central rod outlet flow channel is communicated with the core barrel outlet flow channel. The openings of the central rod inlet flow channel and the central rod outlet flow channel are both provided at the lower end of the central rod. After the piston at the bottom of the central rod reaches the inner top of the core barrel, the central rod inlet flow channel is communicated with the core barrel inlet flow channel and the central rod outlet flow channel is communicated with the core barrel outlet flow channel. At this time, a liquid cold source or salting-out liquid is injected through the central rod.

[0014] As a preferred embodiment of the present invention, a central rod convex block is provided on the top of the piston at the bottom of the central rod, and a core barrel concave groove is provided at the inner top of the core barrel. After the piston at the bottom of the central rod reaches the inner top of the core barrel, the central rod convex block is engaged with the core barrel concave groove. After the piston at the bottom of the central rod reaches the inner top of the core barrel, by rotating the central rod, the core barrel can be driven to rotate synchronously, so that the core barrel mesh holes are aligned with the core barrel outer drill mesh holes.

[0015] As a preferred embodiment of the present invention, a film-forming liquid cavity is formed by enclosing the upper sides of the core barrel, the central rod and the piston at the bottom of the central rod. A central rod film-forming liquid outlet is provided at the lower end of the central rod, and the film-forming liquid cavity, the central rod film-forming liquid outlet and the piston at the bottom of the central rod are communicated in sequence.

[0016] As a preferred embodiment of the present invention, a coolant cavity is provided in the deep-sea environment simulation chamber, and a coolant inlet and a coolant outlet communicated with the coolant cavity are provided on the deep-sea environment simulation chamber. By circulating cryogenic liquid nitrogen, low-temperature alcohol and other cold source liquids through the coolant inlet, the coolant outlet and the coolant cavity, the temperature of the seawater in the seawater cavity is reduced, and the in-situ low-temperature environment of deep-sea combustible ice is simulated.

[0017] As a preferred embodiment of the present invention, a hydraulic oil chamber is formed between the deep-sea environment simulation chamber and the upper side of the stroke piston, and a seawater chamber is formed between the deep-sea environment simulation chamber and the lower side of the stroke piston. The top of the deep-sea environment simulation chamber is provided with a hydraulic oil chamber inlet and a hydraulic oil chamber outlet that communicate with the hydraulic oil chamber, and the bottom of the deep-sea environment simulation chamber is provided with a seawater chamber inlet and a seawater chamber outlet that communicate with the seawater chamber. Seawater is pumped into the seawater chamber through the seawater chamber inlet, and air is discharged from the seawater chamber outlet, so that the whole core sampler is immersed in seawater to simulate the in-situ water environment of the deep sea. Subsequently, the seawater chamber outlet is closed, and a high-pressure pump is used to continuously pump seawater into the seawater chamber to increase the pressure in the seawater chamber and simulate the high-pressure environment of the deep sea. An external tensile machine keeps the central rod in a static state of force balance.

[0018] As a preferred embodiment of the present invention, a check valve is provided inside the piston at the bottom of the central rod.

[0019] As a preferred embodiment of the present invention, a bottom seal is connected to the bottom of the core barrel. During the process of the core entering the core barrel, the bottom seal with a closed petal-shaped structure automatically fits and opens along with the core, aligning the core in the center and closing the bottom of the core barrel at the same time to prevent a large amount of film-forming liquid from leaking.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention can realize the process of reconstructing the in-situ high-pressure and low-temperature environment of the deep sea, simulating the dynamic release of the film-forming liquid during drilling, and forming a solid sealing film layer on the surface of the core. The present invention couples the film-forming principle of freezing-salting out of the film-forming liquid to rapidly form a solid sealing film with high barrier performance on the surface of the core during the core sampling process. This simulation device can realize the step-by-step injection of the cold source and the salting-out liquid into the core sampler from the outside through the construction of a circulation channel, respectively realizing the freezing and salting-out functions, and has practicality in actual core sampling projects, providing a stable and efficient feasible solution for the implementation of the in-situ film-forming project of combustible ice during drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the present invention before core sampling;

[0023] Figure 2 is Figure 1 the schematic structural diagram in the A-A direction of

[0024] Figure 3 is Figure 1 the schematic structural diagram in the B-B direction of

[0025] Figure 4 is Figure 1 the schematic structural diagram in the C-C direction of

[0026] Figure 5 is a schematic structural diagram of the present invention during core sampling;

[0027] Figure 6 are partial structural diagrams of the present invention;

[0028] Figure 7 is a schematic structural diagram of the present invention when coring is completed;

[0029] Figure 8 is Figure 7 a schematic structural diagram in the D-D direction in;

[0030] Figure 9 is a schematic structural diagram of the present invention during the salting-out process;

[0031] Figure 10 is Figure 9 a schematic structural diagram in the E-E direction in;

[0032] Figure 11 is Figure 9 a schematic structural diagram in the F-F direction in.

[0033] In the figure: 1 - central rod; 2 - deep-sea environment simulation chamber; 3 - hydraulic oil chamber inlet; 4 - hydraulic oil chamber outlet; 5 - coolant outlet; 6 - stroke piston; 7 - connecting bearing; 8 - coring barrel; 9 - coring outer drill; 10 - coring barrel inlet flow channel; 11 - coring barrel outlet flow channel; 12 - coring barrel concave groove; 13 - coring outer drill inlet flow channel; 14 - coring outer drill outlet flow channel; 15 - coring outer drill mesh holes; 16 - coolant cavity; 17 - film-forming liquid cavity; 18 - central rod inlet flow channel; 19 - central rod outlet flow channel; 20 - central rod film-forming liquid outlet; 21 - central rod convex block; 22 - central rod bottom piston; 23 - one-way valve; 24 - bottom seal; 25 - core; 26 - seawater chamber; 27 - core base; 28 - coolant inlet; 29 - seawater chamber inlet; 30 - seawater chamber outlet; 31 - coring barrel mesh holes; 32 - coring outer drill limit key groove; 33 - coring barrel limit key; 34 - coring outer drill annular flow channel; 35 - hydraulic oil chamber; 36 - core top film-forming space; 37 - core side film-forming space; 38 - core bottom film-forming space. Specific Embodiments

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Accordingly, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention may be combined with each other.

[0036] As Figures 1 to 11 shown, the in-situ freezing-salting out and film-forming simulation device for combustible ice during drilling of this embodiment includes a deep-sea environment simulation chamber 2. Inside the deep-sea environment simulation chamber 2, there are a stroke piston 6 and a coring outer drill 9 connected to each other. A coring barrel 8 is sleeved inside the coring outer drill 9. The coring barrel 8 is rotatably connected to the stroke piston 6. A central rod bottom piston 22 is sleeved inside the coring barrel 8. A central rod 1 is connected to the central rod bottom piston 22. The central rod 1 extends out of the coring barrel 8, the stroke piston 6, and the deep-sea environment simulation chamber 2. A liquid supply cavity is provided inside the coring outer drill 9. Coring barrel mesh holes 31 are provided on the coring barrel 8. Before the liquid supply cavity communicates with the coring barrel mesh holes 31 after coring is completed, a liquid cold source is injected into the liquid supply cavity. When the coring barrel 8 rotates to make the coring barrel mesh holes 31 communicate with the liquid supply cavity, a salting-out liquid is injected into the liquid supply cavity.

[0037] The coring part is integrally hoisted above the seawater cavity 26 through the central rod 1. By pumping seawater into the seawater cavity 26, air is discharged from the seawater cavity outlet 30, so that the whole coring device is immersed in seawater to simulate the in-situ seawater environment in the deep sea. A high-pressure pump is used to continuously pump seawater into the seawater cavity 26 to increase the pressure inside the seawater cavity 26 and simulate the high-pressure environment in the deep sea. By injecting a cold source liquid into the coolant cavity 16 of the deep-sea environment simulation chamber 2, the temperature of the seawater in the seawater cavity 26 is reduced to simulate the in-situ low-temperature environment of combustible ice in the deep sea.

[0038] During coring, the central rod 1 remains stationary. By pumping hydraulic oil, the stroke piston 6 is pushed, and further the whole coring barrel and the coring outer drill 9 are pushed downward to drill the core 25. A relative movement occurs between the central rod 1 and the coring barrel, reducing the volume of the film-forming liquid cavity 17, and the film-forming liquid gradually displaces seawater in-situ to cover the surface of the core 25.

[0039] After the core 25 completely enters the core barrel 8, a liquid cryogenic source is injected into the liquid supply cavity of the outer core drill 9. After the cryogenic source circulates for a period of time, the film-forming liquid gradually undergoes a phase change reaction to form a solid film layer. The core barrel 8 is rotated to connect the liquid supply cavity with the core barrel mesh holes 31, and then a salting-out liquid is injected into the liquid supply cavity of the outer core drill 9. When the salting-out liquid contacts the solidified film, ions gradually diffuse into the film material, generating a salting-out effect, enhancing the barrier performance and mechanical properties of the film-forming liquid, and improving the quality preservation efficiency. Finally, a high-performance solid sealing film layer is simulated and generated in the low-temperature and high-pressure water environment reconstructed in the deep sea, and the original material information in the core 25 is preserved for a long time.

[0040] The present invention can realize the technological process of reconstructing the in-situ high-pressure and low-temperature environment in the deep sea, simulating the dynamic release of the film-forming liquid during drilling, and forming a solid sealing film layer on the surface of the core 25. The film-forming liquid is a material that will undergo physical and chemical changes in the low-temperature environment of the seabed to form a dense solid quality preservation film layer. In addition, if the film-forming liquid contacts a certain concentration of ionic solution after freezing and solidification, a salting-out effect will occur, improving the mechanical properties and barrier properties of the quality preservation film layer. The present invention couples the film-forming principle of freezing-salting-out of the film-forming liquid to quickly form a solid sealing film with high barrier performance on the surface of the core 25 during the core sampling process. The simulation device can inject the cryogenic source and the salting-out liquid into the core sampler from the outside step by step by constructing a circulation channel, respectively realizing the freezing and salting-out functions, and has practicability in actual core sampling projects, and can provide a stable and efficient feasible solution for the implementation of the in-situ film-forming project of combustible ice during drilling.

[0041] As a preferred embodiment of the present invention, the liquid supply cavity includes an outer core drill inlet flow channel 13, an outer core drill outlet flow channel 14, and an outer core drill annular flow channel 34. The outer core drill inlet flow channel 13 and the outer core drill outlet flow channel 14 are arranged on the circumferential surface of the outer core drill 9, and the outer core drill annular flow channel 34 is arranged at the bottom of the outer core drill 9. The outer core drill annular flow channel 34 is respectively communicated with the outer core drill inlet flow channel 13 and the outer core drill outlet flow channel 14; an outer core drill mesh hole 15 is arranged on the inner wall of the outer core drill 9. When the core barrel 8 rotates to align the core barrel mesh holes 31 with the outer core drill mesh holes 15, the outer core drill inlet flow channel 13 and the outer core drill outlet flow channel 14 are respectively communicated with the core barrel 8.

[0042] When a liquid cold source is introduced into the core outer drill inlet passage 13, the liquid cold source enters the core outer drill outlet passage 14 through the core outer drill annular passage 34, so that the liquid cold source can flow through all circumferential regions of the core outer drill 9 times, ensuring that the film-forming liquid on the surface of the core 25 is evenly cooled, so that the film-forming liquid gradually undergoes a phase change reaction to form a solid film layer. When the core barrel 8 rotates to align the core barrel mesh hole 31 with the core outer drill mesh hole 15, a salting-out liquid is injected into the core outer drill 9. The salting-out liquid enters the core barrel 8 through the core outer drill inlet passage 13, the core outer drill mesh hole 15 and the core barrel mesh hole 31. The salting-out liquid contacts the solidified film, and ions gradually diffuse into the film material, generating a salting-out effect, enhancing the barrier performance and mechanical properties of the film-forming liquid, and improving the quality preservation efficiency.

[0043] Among them, a core barrel limit key 33 is arranged on the outer wall of the core barrel 8, and a core outer drill limit key groove 32 for limiting the core barrel limit key 33 is arranged on the inner wall of the core outer drill 9. In the initial state, there is an angular misalignment of 30° between the core outer drill mesh hole 15 and the core barrel mesh hole 31. When the core barrel 8 rotates, the core outer drill limit key groove 32 limits the core barrel limit key 33. At this time, the core outer drill mesh hole 15 and the core barrel mesh hole 31 are aligned for the medium to flow through.

[0044] Specifically, a core barrel inlet passage 10 and a core barrel outlet passage 11 are arranged at the upper end of the core barrel 8. The core barrel inlet passage 10 is communicated with the core outer drill inlet passage 13, and the core barrel outlet passage 11 is communicated with the core outer drill outlet passage 14; a central rod inlet passage 18 and a central rod outlet passage 19 are arranged on the central rod 1. After the piston 22 at the bottom of the central rod reaches the inner top of the core barrel 8, the central rod inlet passage 18 is communicated with the core barrel inlet passage 10, and the central rod outlet passage 19 is communicated with the core barrel outlet passage 11. The openings of the central rod inlet passage 18 and the central rod outlet passage 19 are both arranged at the lower end of the central rod 1. After the piston 22 at the bottom of the central rod reaches the inner top of the core barrel 8, the central rod inlet passage 18 is communicated with the core barrel inlet passage 10 and the central rod outlet passage 19 is communicated with the core barrel outlet passage 11. At this time, a liquid cold source or a salting-out liquid is injected through the central rod 1.

[0045] A central rod convex block 21 is arranged on the top of the piston 22 at the bottom of the central rod. A core barrel concave groove 12 is arranged at the inner top of the core barrel 8. After the piston 22 at the bottom of the central rod reaches the inner top of the core barrel 8, the central rod convex block 21 is engaged with the core barrel concave groove 12. After the piston 22 at the bottom of the central rod reaches the inner top of the core barrel 8, by rotating the central rod 1, the core barrel 8 can be driven to rotate synchronously so that the core barrel mesh hole 31 is aligned with the core outer drill mesh hole 15.

[0046] Specifically, a film-forming liquid cavity 17 is formed by enclosing the core barrel 8, the central rod 1, and the upper side of the piston 22 at the bottom of the central rod. A central rod film-forming liquid outlet 20 is provided at the lower end of the central rod 1. The film-forming liquid cavity 17, the central rod film-forming liquid outlet 20, and the piston 22 at the bottom of the central rod are connected in sequence. A one-way valve 23 is provided inside the piston 22 at the bottom of the central rod. The bottom of the core barrel 8 is connected with a bottom seal 24. During the process of the core 25 entering the core barrel 8, the bottom seal 24 with a closed petal-shaped structure automatically fits and opens along with the core 25, aligning the core 25 in the center and closing the bottom of the core barrel 8 simultaneously to prevent a large amount of film-forming liquid from leaking.

[0047] Specifically, a coolant cavity 16 is provided inside the deep-sea environment simulation chamber 2. A coolant inlet 28 and a coolant outlet 5 communicating with the coolant cavity 16 are provided on the deep-sea environment simulation chamber 2. By circulating cryogenic liquid nitrogen, low-temperature alcohol and other cold source liquids through the coolant inlet 28, the coolant outlet 5, and the coolant cavity 16, the temperature of the seawater in the seawater cavity 26 is reduced to simulate the in-situ low-temperature environment of deep-sea combustible ice.

[0048] A hydraulic oil cavity 35 is formed by enclosing the upper side of the deep-sea environment simulation chamber 2 and the stroke piston 6. A seawater cavity 26 is formed by enclosing the lower side of the deep-sea environment simulation chamber 2 and the stroke piston 6. A hydraulic oil cavity inlet 3 and a hydraulic oil cavity outlet 4 communicating with the hydraulic oil cavity 35 are provided at the top of the deep-sea environment simulation chamber 2. A seawater cavity inlet 29 and a seawater cavity outlet 30 communicating with the seawater cavity 26 are provided at the bottom of the deep-sea environment simulation chamber 2. Seawater is pumped into the seawater cavity 26 through the seawater cavity inlet 29, and air is discharged from the seawater cavity outlet 30, immersing the whole core sampler in seawater to simulate the in-situ seawater environment in the deep sea. Then, the seawater cavity outlet 30 is closed, and a high-pressure pump is used to continuously pump seawater into the seawater cavity 26 to increase the pressure in the seawater cavity 26, simulating the high-pressure environment in the deep sea. An external tensile machine keeps the central rod 1 in a static state of force balance.

[0049] In summary, the present invention can be divided into the structure of the deep-sea environment simulation chamber 2 and the structure of the core sampling functional part.

[0050] Structure of the deep-sea environment simulation chamber 2:

[0051] 1) The stroke piston 6 can slide sealingly inside the deep-sea environment simulation chamber 2, dividing the deep-sea environment simulation chamber 2 into two parts. The upper part is the oil cylinder cavity, and the lower part is the seawater cavity 26. A hydraulic oil cavity inlet 3 and a hydraulic oil cavity outlet 4 are provided at the top of the deep-sea environment simulation chamber 2, connecting the oil cylinder cavity and the high-pressure pump. A seawater cavity inlet 29 and a seawater cavity outlet 30 are provided at the bottom of the deep-sea environment simulation chamber 2, and the seawater cavity inlet 29 connects the seawater cavity 26 and the high-pressure pump. The inner wall of the deep-sea environment simulation chamber 2 is provided with a coolant inlet 28, a coolant outlet 5, and a coolant cavity 16.

[0052] 2) Structure of the core sampling functional part:

[0053] The coring outer drill 9 is fixedly connected to the stroke piston 6 by screws. The coring barrel 8 is connected to the stroke piston 6 through a bearing and is nested inside the coring outer drill 9, and can rotate relative to the coring outer drill 9. Inside the coring outer drill 9, a coring outer drill inlet flow channel 13 and a coring outer drill outlet flow channel 14 are respectively opened as a whole (as Figure 2 shown). At the bottom of the coring outer drill 9, a coring outer drill annular flow channel 34 is opened to connect the coring outer drill inlet flow channel 13 and the coring outer drill outlet flow channel 14 (as Figure 4 shown). At the top of the coring barrel 8, a coring barrel inlet flow channel 10 and a coring barrel outlet flow channel 11 are provided, which are respectively connected to the coring outer drill inlet flow channel 13 and the coring outer drill outlet flow channel 14. On the outer wall of the coring barrel 8, a coring barrel limit key 33 is provided, and on the inner wall of the coring outer drill 9, a coring outer drill limit key groove 32 is provided. The coring barrel limit key 33 cooperates with the coring outer drill limit key groove 32, so that the coring barrel 8 and the coring outer drill 9 have a relative rotation angle of 30° (as Figure 3 shown). There are six or more groups of evenly distributed coring outer drill mesh holes 15 and coring barrel mesh holes 31 on the inner layer of the coring outer drill 9 and the coring barrel 8 respectively. In the initial state, the coring outer drill mesh holes 15 and the coring barrel mesh holes 31 are angularly misaligned by 30° and are not connected. This kind of pore opening method has multiple layers axially. Inside the center rod 1, a center rod inlet flow channel 18 and a center rod outlet flow channel 19 are opened, and the bottom is fixedly connected to the center rod bottom piston 22. Inside the center rod bottom piston 22, a center rod film-forming liquid outlet 20 is opened, and a one-way valve 23 is installed. The center rod 1, the center rod bottom piston 22, the coring barrel 8, and the coring outer drill 9 enclose a film-forming liquid cavity 17, and the film-forming liquid is stored in the film-forming liquid cavity 17. At the top of the center rod bottom piston 22, a center rod convex block 21 is provided, and on the inner wall surface of the top of the coring barrel 8, a concave groove of the coring barrel 8 is provided, and the center rod convex block 21 can be buckled with the concave groove of the coring barrel 8. The center rod 1 can slide relative to the deep-sea environment simulation chamber 2 and the coring barrel 8. The center rod 1 is connected to an external tensile machine. The core 25 is located on the core 25 base and is placed at the lower end of the seawater cavity 26 as a whole.

[0054] Working process:

[0055] 1) Before coring (as Figures 1 to 4 shown)

[0056] The film-forming liquid is pre-placed in the film-forming liquid cavity 17, and the coring part is hoisted as a whole above the seawater cavity 26 through the central rod 1. Seawater is pumped into the seawater cavity 26 through the seawater cavity inlet 29, and air is discharged from the seawater cavity outlet 30, so that the whole corer is immersed in seawater to simulate the in-situ deep-sea water environment. Subsequently, the seawater cavity outlet 30 is closed, and a high-pressure pump is used to continuously pump seawater into the seawater cavity 26 to increase the pressure in the seawater cavity 26 and simulate the deep-sea high-pressure environment. An external tensile machine keeps the central rod 1 in a static state of force balance. Liquid nitrogen, low-temperature alcohol and other cold-source liquids are circulated through the coolant inlet 28, the coolant outlet 5 and the coolant cavity 16 to reduce the seawater temperature in the seawater cavity 26 and simulate the in-situ low-temperature environment of deep-sea combustible ice.

[0057] 2) When coring (as Figure 5 and Figure 6 shown)

[0058] When coring, the central rod 1 remains stationary. Hydraulic oil is pumped into the cylinder cavity through the hydraulic oil cavity inlet 3 to push the stroke piston 6, and further push the coring barrel 8 and the coring outer drill 9 to move downward as a whole to drill the core 25. A relative movement occurs between the central rod 1 and the coring barrel 8, reducing the volume of the film-forming liquid cavity 17, and the film-forming liquid gradually discharges through the central rod film-forming liquid outlet 20 and the one-way valve 23 to displace seawater in-situ and cover the surface of the core 25. During the process of the core 25 entering the coring barrel 8, the bottom seal 24 is a closed petal-shaped structure made of high-elastic spring steel material, which can automatically open and fit the core 25, align the core 25 in the center, and at the same time seal the bottom of the coring barrel 8 to prevent a large amount of film-forming liquid from leaking.

[0059] 3) After coring, freeze and form a film (as Figure 7 and Figure 8 shown)

[0060] After the core 25 completely enters the coring barrel 8, the bottom seal 24 automatically rebounds to seal the bottom of the coring barrel 8, preventing the film-forming liquid at the bottom of the coring barrel 8 from leaking and ensuring the complete film-forming seal at the bottom of the coring barrel 8. The top surface of the core 25 and the bottom surface of the piston 22 at the bottom of the central rod form the top film-forming space of the core 25, the side surface of the core 25 and the inner wall of the coring barrel 8 form the side film-forming space of the core 25, and the bottom surface of the core 25 and the bottom seal 24 form the bottom film-forming space of the core 25. All the film-forming spaces are completely filled with the film-forming liquid. After the central rod 1 approaches the top of the coring barrel 8, the central rod inlet flow channel 18 → the coring barrel inlet flow channel 10 → the coring outer barrel inlet flow channel → the coring outer drill annular flow channel 34 → the coring outer barrel outlet flow channel → the coring barrel inlet flow channel 10 → the central rod outlet flow channel 19 form a circulation channel (as Figure 8 shown). Liquid nitrogen, low-temperature alcohol and other liquid cold sources are circulated through the central rod inlet flow channel 18. After the cold source is circulated for a period of time, the film-forming liquid gradually undergoes a phase change reaction to form a solid film layer.

[0061] 4) Salting-out effect after coring (as Figures 9 to 11 shown)

[0062] The convex block 21 of the central rod is matched with the concave groove of the coring barrel 8. By rotating the central rod 1, the coring barrel 8 is driven to rotate. The coring barrel 8 and the outer coring drill 9 rotate relative to each other. Under the limiting action of the coring barrel limiting key 33 and the outer coring drill limiting key groove 32, the mesh holes 31 of the coring barrel can be aligned with the mesh holes 15 of the outer coring drill, and the mesh holes 31 of the coring barrel are communicated with the inlet flow channel or the outlet flow channel of the outer coring barrel (as Figure 11 shown). The salting-out liquid (a high-concentration solution composed of salts such as sodium citrate, sodium sulfate, potassium sulfate, sodium carbonate, potassium carbonate, sodium chloride, etc., which have strong salting-out effects and Hofmeister effects) is pumped in a cycle from the central rod inlet flow channel 18 → the coring barrel inlet flow channel 10 → the outer coring barrel inlet flow channel → the outer coring drill annular flow channel 34 → the outer coring barrel outlet flow channel → the coring barrel inlet flow channel 10 → the central rod outlet flow channel 19 (as Figure 10 shown). When the salting-out liquid contacts the solidified film, ions gradually diffuse into the film material, producing a salting-out effect, enhancing the barrier performance and mechanical properties of the film-forming liquid, and improving the quality preservation efficiency. Finally, a high-performance solid sealing film layer is simulated and generated in the low-temperature and high-pressure water environment reconstructed in the deep sea, and the original material information in the core 25 is stored for a long time.

[0063] The present invention is not limited to the above optional embodiments. Anyone can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as the technical solutions fall within the scope defined by the claims of the present invention, they are all within the protection scope of the present invention.

Claims

1. A simulation device for in-situ freezing-salting out and film formation while drilling of combustible ice, characterized in that: It includes a deep - sea environment simulation chamber (2). Inside the deep - sea environment simulation chamber (2), there are a reciprocating piston (6) and a core - drilling outer drill (9) which are interconnected. A core barrel (8) is sleeved inside the core - drilling outer drill (9). The core barrel (8) is rotatably connected to the reciprocating piston (6). A central rod bottom piston (22) is sleeved inside the core barrel (8). A central rod (1) is connected to the central rod bottom piston (22). The central rod (1) extends out of the core barrel (8), the reciprocating piston (6), and the deep - sea environment simulation chamber (2). A liquid - supply cavity is arranged inside the core - drilling outer drill (9). Core - barrel mesh holes (31) are arranged on the core barrel (8). Before the liquid - supply cavity is connected to the core - barrel mesh holes (31) after coring is completed, a liquid cold source is injected into the liquid - supply cavity. When the core barrel (8) rotates to make the core - barrel mesh holes (31) communicate with the liquid - supply cavity, a salting - out liquid is injected into the liquid - supply cavity. The liquid - supply cavity includes a core - drilling outer - drill inlet channel (13), a core - drilling outer - drill outlet channel (14), and a core - drilling outer - drill annular channel (34). The core - drilling outer - drill inlet channel (13) and the core - drilling outer - drill outlet channel (14) are arranged on the circumferential surface of the core - drilling outer drill (9). The core - drilling outer - drill annular channel (34) is arranged at the bottom of the core - drilling outer drill (9). The core - drilling outer - drill annular channel (34) is respectively communicated with the core - drilling outer - drill inlet channel (13) and the core - drilling outer - drill outlet channel (14). Core - drilling outer - drill mesh holes (15) are arranged on the inner wall of the core - drilling outer drill (9). When the core barrel (8) rotates to align the core - barrel mesh holes (31) with the core - drilling outer - drill mesh holes (15), the core - drilling outer - drill inlet channel (13) and the core - drilling outer - drill outlet channel (14) are respectively communicated with the core barrel (8). An inlet channel (10) and an outlet channel (11) of the core barrel are arranged at the upper end of the core barrel (8). The inlet channel (10) of the core barrel is communicated with the inlet channel (13) of the core - drilling outer drill. The outlet channel (11) of the core barrel is communicated with the outlet channel (14) of the core - drilling outer drill. An inlet channel (18) and an outlet channel (19) of the central rod are arranged on the central rod (1). After the central rod bottom piston (22) reaches the inner top of the core barrel (8), the inlet channel (18) of the central rod is communicated with the inlet channel (10) of the core barrel, and the outlet channel (19) of the central rod is communicated with the outlet channel (11) of the core barrel. The upper sides of the core barrel (8), the central rod (1), and the central rod bottom piston (22) enclose a film - forming liquid cavity (17). A central - rod film - forming liquid outlet (20) is arranged at the lower end of the central rod (1). The film - forming liquid cavity (17), the central - rod film - forming liquid outlet (20), and the central rod bottom piston (22) are sequentially communicated. A coolant cavity (16) is arranged inside the deep - sea environment simulation chamber (2). A coolant inlet (28) and a coolant outlet (5) which are communicated with the coolant cavity (16) are arranged on the deep - sea environment simulation chamber (2). The deep - sea environment simulation chamber (2) and the upper side of the stroke piston (6) enclose a hydraulic oil chamber (35), and the deep - sea environment simulation chamber (2) and the lower side of the stroke piston (6) enclose a seawater chamber (26). The top of the deep - sea environment simulation chamber (2) is provided with a hydraulic oil chamber inlet (3) and a hydraulic oil chamber outlet (4) that communicate with the hydraulic oil chamber (35), and the bottom of the deep - sea environment simulation chamber (2) is provided with a seawater chamber inlet (29) and a seawater chamber outlet (30) that communicate with the seawater chamber (26).

2. The in-situ freezing-salting out and film-forming simulation device for combustible ice while drilling according to claim 1, wherein: A core barrel limit key (33) is provided on the outer wall of the core barrel (8), and a core outer drill limit key groove (32) for limiting the core barrel limit key (33) is provided on the inner wall of the core outer drill (9), which is beneficial to align the core barrel mesh holes (31) with the core outer drill mesh holes (15).

3. The in-situ freezing-salting out film-forming simulation device for combustible ice while drilling according to claim 1, wherein: A core rod bottom piston (22) is provided with a core rod convex block (21) at the top, and a core barrel concave groove (12) is provided at the inner top of the core barrel (8). After the core rod bottom piston (22) reaches the inner top of the core barrel (8), the core rod convex block (21) engages with the core barrel concave groove (12).

4. A simulation device for in-situ freezing-salting out and film formation while drilling combustible ice according to claim 1, characterized in that: A one - way valve (23) is provided inside the core rod bottom piston (22).

5. A simulation device for in-situ freezing-salting out and film formation while drilling of combustible ice according to any one of claims 1 to 4, characterized in that: The bottom of the core barrel (8) is connected to a bottom seal (24).

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