A pressurized jet suction and well-washing tool for natural gas hydrate reservoirs

Abstract

The present invention discloses a boosted ejector suction jet well-washing tool for natural gas hydrate reservoirs, comprising a boosted ejector pipe, a rotor, a drive core shaft, a suction turbine, and an ejector head. The rotor is mounted on the drive core shaft near the well-washing fluid input end of the boosted ejector pipe, the suction turbine is mounted on the drive core shaft near the mixed liquid output end of the boosted ejector pipe, and the ejector head is mounted on the mixed liquid output end of the boosted ejector pipe. The wall of the boosted ejector pipe is provided with a suction hole. When the well-washing fluid flows through the rotor, the rotor is driven to rotate, and the rotor drives the suction turbine to rotate via the drive core shaft. Liquid outside the boosted ejector pipe is sucked into the boosted ejector pipe through the suction hole, mixed with the well-washing fluid, and then ejected from the ejector head. The present invention uses the flow of well-washing fluid as a power source, drives the rotor through the flow of well-washing fluid, and drives the suction turbine to rotate via the drive core shaft, forming a boosted drainage method for circulating liquid inside and outside the pipe, and ejecting high-pressure liquid to the blocked part, effectively treating the blocked part of the outer wall of the screen pipe and achieving the purpose of efficient cleaning.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas hydrate exploitation, and in particular to a pressurized injection suction jet well-washing tool based on a natural gas hydrate reservoir. Background Art

[0002] Due to their vast reserves and widespread distribution, natural gas hydrates are considered a new clean energy source with enormous potential and are becoming a strategic future energy frontier for global competition. my country's South China Sea is rich in natural gas hydrate resources, primarily occurring in shallow, unconsolidated muddy silt reservoirs on deepwater continental slopes. These reservoirs feature fine grains and a high mud content. For example, in the Shenhu area, the median sand grain size ranges from 16.0 to 25.0 μm. Grain size distribution tests of some core samples show that clay and silt particles smaller than 63 μm account for nearly 94%. With hydrate phase transition and decomposition, multiphase flow, and changes in stress state, the reservoirs are susceptible to creep deformation, resulting in a decrease in original porosity and permeability, severely impacting natural gas hydrate production and the timeliness of extraction. Therefore, addressing the series of issues caused by hydrate reservoir creep has become a key technical challenge hindering the industrial development of natural gas hydrate resources.

[0003] Research has found that hydrate reservoir creep, on the one hand, causes the pore throats of the seepage channels to shrink, reducing porosity and permeability. On the other hand, the small amount of free solid particles originally in the hydrate reservoir, as well as solid particles that fall off the reservoir skeleton during extraction, migrate and accumulate at the necking points, accelerating the blockage of pore throats and further reducing the reservoir's porosity and permeability. Therefore, timely clearing the solid particles blocking the reservoir's seepage channels, thereby improving the permeability of the near-wellbore area of ​​the natural gas hydrate reservoir and increasing the production efficiency of gas and water from hydrate decomposition, is one of the key technologies for efficient hydrate development.

[0004] Currently, in several hydrate pilot projects around the world, drilling is performed within the reservoir to create a depressurized wellbore environment. Mechanical sand screens are then lowered into the wellbore to prevent muddy silt particles from entering the wellbore. However, as the depressurization continues, solid particles in the reservoir will gradually block the seepage channels and accumulate on the outer wall of the screen to form a dense barrier layer. Existing downhole tools can only clean inside the screen and cannot effectively deal with the blockage on the outer wall of the screen, resulting in poor cleaning results. Summary of the Invention

[0005] The object of the present invention is to provide a pressurized injection suction jet well washing tool based on a natural gas hydrate reservoir with an efficient cleaning function.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A pressurized ejector suction jet well washing tool based on a natural gas hydrate reservoir comprises a pressurized ejector pipe, a rotor, a transmission core shaft, a suction turbine and an ejector head. The rotor is mounted on the transmission core shaft and is close to the well washing fluid input end of the pressurized ejector pipe. The suction turbine is mounted on the transmission core shaft and is close to the mixed liquid output end of the pressurized ejector pipe. The ejector head is mounted on the mixed liquid output end of the pressurized ejector pipe. A suction hole is provided on the wall of the pressurized ejector pipe. When the well washing fluid flows through the rotor, the rotor is driven to rotate. The rotor drives the suction turbine to rotate via the transmission core shaft. The liquid outside the pressurized ejector pipe is sucked into the pressurized ejector pipe through the suction hole, mixed with the well washing fluid, and then ejected from the ejector head.

[0008] Furthermore, both ends of the transmission core shaft are mounted in the central hole of the support frame in the boost ejector tube through bearings, and liquid passing holes are distributed on the support frame and around the central hole.

[0009] Furthermore, steps are provided on the inner wall surface of the boost ejector tube and near the two ends of the boost ejector tube, and the two support frames are respectively tightly attached to the two steps. The threaded joints at both ends of the transmission core shaft respectively pass through the center holes of the two support frames and are threadedly connected to the two clamping nuts. The two clamping nuts press the support frames onto the two steps.

[0010] Furthermore, a middle support frame is provided in the middle of the boost ejector tube, and the transmission core shaft is installed in the center hole of the middle support frame through a bearing.

[0011] Furthermore, the rotor is a supercharged power turbine group, and the supercharged power turbine group is composed of multiple supercharged power turbines.

[0012] Furthermore, there are a plurality of suction holes, and the plurality of suction holes are distributed along the circumferential direction of the pressurized ejector tube.

[0013] Furthermore, the ejector tube includes a booster nipple and an ejector nipple, a Venturi tube is provided between the booster nipple and the ejector nipple, a negative pressure zone is formed between the reduced diameter section of the Venturi tube and the inner wall of the ejector nipple, and the suction hole is provided on the ejector nipple and is located in the negative pressure zone.

[0014] Furthermore, the external threaded end of the boosting short section and the internal threaded end of the ejector short section are threadedly connected, one end of the venturi tube is pressed against the end face of the boosting short section, an outer step is provided on the outer wall surface of the venturi tube, an inner step is provided on the inner wall surface of the ejector short section, and a compression spring is mounted on the venturi tube, and the compression spring is located between the inner step and the outer step.

[0015] Furthermore, a support washer is mounted on the venturi tube, one end of the compression spring presses on the outer step, and the other end presses on the support washer, and the support washer is tightly attached to the inner step.

[0016] Furthermore, a sliding sealing ring is provided between the venturi tube and the ejector nipple.

[0017] The beneficial effects of the present invention are:

[0018] This application uses the flow of well washing fluid as the power source, drives the rotor through the flow of well washing fluid, and the rotor drives the suction turbine to rotate through the transmission core shaft, forming a pressurized drainage method for liquid circulation inside and outside the pipe, and injecting high pressure to the blockage position, thereby effectively treating the blockage part of the outer wall of the screen pipe and achieving the purpose of efficient cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is further described with reference to the accompanying drawings. However, the embodiments in the accompanying drawings do not limit the present invention in any way. A person skilled in the art can derive other drawings based on the following drawings without inventive effort.

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 for Figure 1 The longitudinal half-section structure diagram shown;

[0022] Figure 3 for Figure 1 The longitudinal full-section structure diagram shown;

[0023] Figure 4 for Figure 3 An enlarged view of point A is shown;

[0024] Figure 5 for Figure 3 An enlarged view of point B is shown.

[0025] In the figure: 1. Booster ejector tube; 2. Rotor; 3. Drive core shaft; 4. Suction turbine; 5. Injector head; 6. Well washing fluid input port; 7. Suction hole; 8. Support frame; 9. Step; 10. Compression nut; 11. Middle support frame; 12. Booster nipple; 13. Ejector nipple; 14. Venturi tube; 15. Negative pressure area; 16. Inner step; 17. Compression spring; 18. Support washer; 19. Sliding seal; 20. Outer step. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other unless there is a conflict.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper surface", "lower surface", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "forward", "reverse", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0028] like Figure 1 、 2 As shown, a boosted ejector suction jet well-washing tool for natural gas hydrate reservoirs includes a boosted ejector pipe 1, a rotor 2, a drive shaft 3, a suction turbine 4, and an ejector head 5. The rotor 2 is mounted on the drive shaft 3 near the well-washing fluid input end 6 of the boosted ejector pipe 1. The suction turbine 4 is mounted on the drive shaft 3 near the mixed liquid output end of the boosted ejector pipe 1. The ejector head 5 is mounted on the mixed liquid output end of the boosted ejector pipe 1. Suction holes 7 are provided on the wall of the boosted ejector pipe 1. When well-washing fluid flows through the rotor 2, it drives the rotor 2 to rotate. The rotor 2 drives the suction turbine 4 via the drive shaft 3. Liquid outside the boosted ejector pipe 1 is sucked into the boosted ejector pipe 1 through the suction holes 7, mixed with the well-washing fluid, and then ejected from the ejector head 5. Multiple suction holes 7 are provided, distributed along the circumference of the boosted ejector pipe.

[0029] Both ends of the transmission core shaft 3 are mounted in the central hole of the support frame 8 in the boost ejector tube through bearings. Liquid passing holes are distributed on the support frame 8 and around the central hole.

[0030] like Figure 3 As shown, the ejector tube 1 includes a booster short section 12 and an ejector short section 13, a venturi tube 14 is provided between the booster short section 12 and the ejector short section 13, a negative pressure area 15 is formed between the reduced diameter section of the venturi tube 14 and the inner wall of the ejector short section 13, and the suction hole 7 is provided on the ejector short section 13 and is located at the position of the negative pressure area 15.

[0031] like Figure 4As shown, the specific connection method is as follows: the external threaded end of the boosting short section 12 and the internal threaded end of the ejector short section 13 are threadedly connected, one end of the venturi tube 14 is pressed against the end face of the boosting short section 12, an outer step 20 is provided on the outer wall surface of the venturi tube 14, and an inner step 16 is provided on the inner wall surface of the ejector short section 13. A compression spring 17 and a support washer 18 are mounted on the venturi tube 14, one end of the compression spring 17 is pressed against the outer step 20, and the other end is pressed against the support washer 18, the support washer 18 is tightly attached to the inner step 16, and a sliding sealing ring 19 is provided between the venturi tube 14 and the ejector short section 13.

[0032] like Figure 5 As shown, the support frame 8 is installed in a detachable manner. Steps 9 are provided on the inner wall surface of the boost ejector tube 1 and near the two ends of the boost ejector tube. Specifically, the steps 9 are provided on the inner wall surfaces of the boost short section 12 and the ejector short section 13. The two support frames 8 are respectively tightly attached to the two steps 9. The threaded joints at both ends of the transmission core shaft 3 pass through the center holes of the two support frames 8 and are threadedly connected to the two clamping nuts 10. The two clamping nuts 10 press the support frame 8 onto the two steps 9. A middle support frame 11 is provided in the middle of the boost ejector tube 1, and the transmission core shaft 3 is installed in the center hole of the middle support frame 11 through a bearing. The rotor 2 is a boost power turbine group, and the boost power turbine group is composed of multiple boost power turbines.

[0033] Working principle: The well washing tool is connected to the bottom of the drill pipe or oil pipe. The well washing fluid is pumped into the well washing tool from the drill pipe or oil pipe. The application uses the flow of well washing fluid as the power source to drive the upper booster turbine (rotor) to rotate. The upper booster turbine (rotor) drives the suction turbine to rotate through the transmission core shaft. A negative pressure area 15 is formed between the reduced diameter section of the venturi tube 14 and the inner wall of the ejector short section 13. The fluid outside the pipe is sucked into the pipe through the suction hole and mixed with the well washing fluid to increase the liquid flow in the pipe. The fluid then passes through the Venturi channel in the ejector short section 13 to further increase the liquid pressure in the pipe, forming a high-pressure flow, and finally forming a high-speed jet through the injection port of the ejector head 5. Under the impact of the high-speed jet, the solid particles inside and outside the screen tube are loosened and fall off, and carried by the flushing fluid into the suction hole, forming a local liquid circulation, thereby achieving the unblocking of the outer wall of the screen tube.

[0034] In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent. Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A pressurized injection suction jet well washing tool based on natural gas hydrate reservoir, characterized in that: The invention comprises a supercharging ejector pipe, a rotor, a transmission core shaft, a suction turbine and an injection head, wherein the rotor is mounted on the transmission core shaft and is close to the well washing fluid input end of the supercharging ejector pipe, the suction turbine is mounted on the transmission core shaft and is close to the mixed liquid output end of the supercharging ejector pipe, the injection head is mounted on the mixed liquid output end of the supercharging ejector pipe, a suction hole is provided on the pipe wall of the supercharging ejector pipe, when the well washing fluid flows through the rotor, the rotor is driven to rotate, and the rotor drives the suction turbine to rotate through the transmission core shaft, and the liquid outside the supercharging ejector pipe is sucked into the supercharging ejector pipe through the suction hole, mixed with the well washing fluid, and then ejected from the injection head; both ends of the transmission core shaft are mounted in the central hole of the support frame in the supercharging ejector pipe through bearings, and liquid passing holes are distributed on the support frame and around the central hole; The ejector tube includes a booster nipple and an ejector nipple, a Venturi tube is provided between the booster nipple and the ejector nipple, a negative pressure zone is formed between the reduced diameter section of the Venturi tube and the inner wall of the ejector nipple, the suction hole is provided on the ejector nipple and is located in the negative pressure zone; the external threaded end of the booster nipple and the internal threaded end of the ejector nipple are threadedly connected, one end of the Venturi tube is pressed against the end face of the booster nipple, an outer step is provided on the outer wall surface of the Venturi tube, an inner step is provided on the inner wall surface of the ejector nipple, a compression spring is mounted on the Venturi tube, and the compression spring is located between the inner step and the outer step; a support gasket is mounted on the Venturi tube, one end of the compression spring is pressed against the outer step, and the other end is pressed against the support gasket, and the support gasket is tightly attached to the inner step.

2. The pressurized injection suction jet well washing tool based on the natural gas hydrate reservoir according to claim 1 is characterized in that Steps are provided on the inner wall surface of the boost ejector tube and near the two ends of the boost ejector tube. The two support frames are respectively tightly attached to the two steps. The threaded joints at both ends of the transmission core shaft respectively pass through the center holes of the two support frames and are threadedly connected to the two clamping nuts. The two clamping nuts press the support frames onto the two steps.

3. The pressurized injection suction jet well flushing tool based on the natural gas hydrate reservoir according to claim 2 is characterized in that: A middle support frame is provided in the middle of the pressurized ejector tube, and the transmission core shaft is installed in the center hole of the middle support frame through a bearing.

4. The pressurized injection suction jet well flushing tool based on the natural gas hydrate reservoir according to claim 1 is characterized in that: The rotor is a supercharged power turbine group, and the supercharged power turbine group is composed of multiple supercharged power turbines.

5. The pressurized injection suction jet well flushing tool based on the natural gas hydrate reservoir according to claim 1 is characterized in that: There are multiple suction holes, and the multiple suction holes are distributed along the circumferential direction of the boost ejector tube.

6. The pressurized injection suction jet well flushing tool based on the natural gas hydrate reservoir according to claim 1 is characterized in that: A sliding sealing ring is provided between the venturi tube and the ejector nipple.

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