A downhole throttling structure and a gas production method based on the structure

Abstract

This invention relates to the field of oil and gas production engineering in the petroleum industry, and discloses a downhole throttling structure and a gas production method based on the structure. The downhole throttling structure includes: a mounting base for fixed connection with a gas pipe, the mounting base having a first inner cavity; and a downhole throttling device fitted within the first inner cavity, the outer wall of the downhole throttling device being connected to the side wall of the first inner cavity by a pin; wherein the pin is capable of breaking under external force, thereby disrupting the connection between the downhole throttling device and the mounting base. The detachable mounting base and downhole throttling device structure can simultaneously meet the process requirements of throttling production and the plunger gas lift stage, significantly reducing the time required for the corresponding process layout, improving production efficiency, and reducing process costs.

Description

Technical Field

[0001] This invention relates to the field of oil and gas production engineering in the petroleum industry, and more specifically, to a downhole throttling structure and a gas production method based on the structure. Background Technology

[0002] Shale gas wells are developed using a depletion-type development process. Initially, they have high pressure and large gas production, requiring throttling production to control the production pressure differential. However, as the well pressure and production rapidly decline, the formation energy continuously diminishes, quickly entering a low-pressure, low-production stage. The well's own energy is insufficient to bring the liquid inside the wellbore to the surface, causing liquid accumulation in the wellbore, increasing wellbore pressure loss, and affecting normal production. Therefore, drainage processes need to be implemented to maintain stable production. Moreover, the plunger gas lift process is the most economical and effective main technology for shale gas wells, and its application rate is expected to exceed 50%.

[0003] Currently, in the early stages of shale gas well production, surface needle valves are used in conjunction with water jacket furnaces or downhole throttles to control production. In the middle and later stages, when the wells experience poor liquid carrying capacity, plunger technology is implemented to stabilize the wells. The entire shale gas extraction cycle requires two construction operations, with two different process tubing strings designed to meet the drainage needs at different stages.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address the issue of multiple construction operations caused by the need to employ two different processes to meet the extraction requirements at different stages in the existing shale gas extraction cycle, this invention provides two solutions. Firstly, it offers a downhole throttling structure. Through structural design, including a detachable limiting sleeve and throttling nozzle, it can meet the requirements of different processes applied during the shale gas extraction cycle. Secondly, this invention provides a gas extraction method. Based on the aforementioned downhole throttling structure, it can quickly achieve process switching at different stages of shale gas extraction, thereby reducing extraction time and construction costs.

[0006] This invention is achieved through the following technical solution:

[0007] First aspect

[0008] This invention relates to a downhole throttling structure, comprising: a mounting base for fixed connection with a gas pipe, the mounting base having a first inner cavity; and a downhole throttling device sleeved in the first inner cavity, the outer wall of the downhole throttling device being connected to the side wall of the first inner cavity by a pin; wherein the pin is capable of breaking under external force, thereby disrupting the connection between the downhole throttling device and the mounting base.

[0009] In this solution, through the structural design of the downhole choke structure, a detachable mounting base and downhole choke structure are adopted. In the early stage of gas well production, downhole flow can be cut off through the downhole choke structure, thereby achieving gas well cut-off production. After the gas well has been producing for a period of time, when the gas volume is low and enters the low-pressure, low-production stage, the gas well's own energy is insufficient to bring the liquid in the wellbore to the surface. By adopting a plunger gas lift process, production can be assisted in achieving gas well production in the low-pressure, low-production stage. Furthermore, in this production stage, due to the disruption of the connection between the mounting base and the downhole choke, This effectively increases the inner diameter of the flow channel within the gas well, facilitating shale gas production. Furthermore, since the mounting base is connected to the gas pipe, it provides a corresponding downhole limiter for the subsequent plunger gas lift process, eliminating the need to deploy the downhole limiter again, thus saving operational steps and meeting the process requirements of the plunger gas lift stage. In summary, the use of this downhole throttling structure simultaneously satisfies the process requirements of both throttling production and the plunger gas lift stage, significantly reducing the time required for the corresponding process setup, improving production efficiency, and lowering process costs.

[0010] Furthermore, the downhole throttle has a second inner cavity coaxially arranged with the first inner cavity, the second inner cavity including a feed end; the downhole throttle is also provided with a throttle nozzle, the throttle nozzle being sleeved in the feed end.

[0011] Furthermore, the second inner cavity also includes a discharge end, which is a frustum-shaped structure, with the smaller diameter end of the discharge end located close to the feed end.

[0012] Furthermore, the end of the feed end near the small-diameter end of the discharge end is provided with a stepped surface, which is used to cooperate with the throttling nozzle to limit the relative position of the throttling nozzle in the axial direction of the feed end.

[0013] Furthermore, the throttling nozzle includes a nozzle sleeve and a nozzle, the nozzle being detachably fitted inside the nozzle sleeve, and the nozzle sleeve being fitted inside the feed end.

[0014] Furthermore, the first inner cavity includes a guide section and an installation section. The downhole throttle is fitted in the installation section. The guide section has a frustum-shaped structure, and the small-diameter end of the guide section is located close to the installation section.

[0015] Furthermore, the inner wall of the cavity slides and seals with the side wall of the downhole throttle.

[0016] Second aspect

[0017] This invention also relates to a gas production method based on the above-mentioned downhole throttling structure, comprising the following steps:

[0018] In the initial stage of gas well production, the gas pipe of the installation seat of the downhole throttling structure is fixedly connected to achieve production by downhole throttling.

[0019] In the mid-to-late stages of gas well production, when the formation energy decreases and downhole throttling is no longer required, the connection between the downhole throttling device and the mounting base is actively disrupted to separate the downhole throttling device from the mounting base and change the inner diameter of the gas pipe.

[0020] Gas extraction is carried out using a plunger process.

[0021] Furthermore, actively disrupting the connection between the downhole throttle and the mounting base specifically includes the following steps:

[0022] A ball is inserted into the tracheal cavity through the tracheal inlet, and the ball is used to seal the end of the downhole throttle near the tracheal inlet.

[0023] A pressurizing device is used to pressurize the inner cavity of the gas pipe through the gas pipe inlet, thereby disrupting the connection between the downhole choke and the mounting base and achieving separation of the downhole choke from the mounting base.

[0024] Furthermore, when the downhole throttling structure includes a throttling nozzle that is detachably connected to the downhole throttling device, the size of the throttling nozzle is determined based on the prediction of hydrate formation in the gas well to be put into production, and then connected to the downhole throttling device to realize the assembly of the downhole throttling device.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] This invention relates to a downhole throttling structure, which adopts a detachable mounting base and a downhole throttling device structure, and can simultaneously meet the process requirements of throttling production and plunger gas lift stage, greatly reducing the time required to arrange the corresponding stages, improving production efficiency, and reducing process costs.

[0027] This invention also relates to a gas extraction method, which, based on the aforementioned downhole throttling structure, enables rapid switching of processes at different stages during shale gas extraction, thereby reducing extraction time and construction costs. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0029] Figure 1 This is a schematic diagram illustrating the interaction between the downhole throttling structure and the ball provided in an embodiment of the present invention.

[0030] Figure 2This is a schematic diagram of the structure of the mounting base provided in an embodiment of the present invention;

[0031] Figure 3 This is an exploded schematic diagram of a downhole throttle provided in an embodiment of the present invention;

[0032] Figure 4 A flowchart of a gas extraction method provided in an embodiment of the present invention.

[0033] The reference numerals in the figure are as follows:

[0034] 100-Mounting base, 111-Guide section, 112-Mounting section, 200-Downhole throttle, 210-Second inner cavity, 211-Infeed end, 212-Outfeed end, 220-Throttle nozzle, 221-Nose sleeve, 222-Nose, 300-Pin, 400-Ball. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0037] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0039] Example

[0040] like Figure 1 As shown, this embodiment of the invention relates to a downhole throttling structure, comprising: a mounting base 100 for fixed connection with a gas pipe, the mounting base 100 having a first inner cavity; and a downhole throttling device 200 sleeved in the first inner cavity, the outer wall of the downhole throttling device 200 being connected to the side wall of the first inner cavity by a pin 300; wherein the pin 300 is capable of breaking under external force, thereby disrupting the connection between the downhole throttling device 200 and the mounting base 100.

[0041] It should be noted that the downhole throttle 200, as a throttling device, is mainly intended to reduce the gas flow path, thereby achieving throttling.

[0042] Specifically, the downhole throttling method simplifies the surface throttling device compared to the surface needle valve combined with a water jacket furnace. Utilizing the high temperature of the downhole environment, it can alleviate the problem of ice blockage after throttling and effectively save on the investment costs of surface water jacket furnaces and other equipment.

[0043] In this context, the downhole throttling structure serves as the working device for achieving downhole throttling production. Therefore, when the mounting base 100 is fixedly connected to the gas pipe, the first inner cavity should communicate with the inner cavity of the gas pipe to achieve gas collection from the gas well. Since the downhole throttling device 200 is sleeved in the first inner cavity, to avoid mutual interference between the gas pipe and the downhole throttling device 200, the specific connection relationship between the gas pipe, the downhole throttling device 200, and the mounting base 100 should be as follows: the mounting base 100 is sleeved in the gas pipe, and the downhole throttling device 200 is located in the cavity of the mounting base 100. Based on this, the end face of the mounting base 100 should form a stepped surface structure relative to the inner wall of the gas pipe. The corresponding stepped surface can serve as the limiting surface in the subsequent plunger gas lift process, thereby achieving plunger limiting and reducing the need to install a limiter in the gas pipe during the plunger gas lift process. This effectively improves production efficiency and reduces process costs.

[0044] In one specific embodiment of connecting the downhole choke 200 and the mounting base 100 with the pin 300, a through hole is provided on the side wall of the mounting base 100 for the pin 300 to pass through, and a positioning hole is provided on the outer side wall of the downhole choke 200 for the pin 300 to cooperate with each other. The end of the pin 300 passes through the through hole to cooperate with the positioning hole, thereby establishing the connection between the two.

[0045] Furthermore, as a technical solution to ensure the tight fit between the pin 300 and the positioning hole, the positioning hole is a threaded hole, and the end of the pin 300 is provided with a thread that mates with the threaded hole, thereby ensuring the tight fit between the two.

[0046] In this solution, through the structural design of the downhole throttling structure, a detachable mounting base 100 and a downhole throttling device 200 are adopted. In the initial stage of gas well production, downhole throttling can be achieved through the downhole throttling device 200, thereby enabling gas well production through throttling. After a period of production, when the gas volume is low and enters a low-pressure, low-production stage, the gas well's own energy is insufficient to bring the liquid in the wellbore to the surface. A plunger gas lift process is then employed to assist in achieving production during this low-pressure, low-production stage. Furthermore, during this production stage, due to the connection between the mounting base 100 and the downhole throttling device 200... The disruption of the system can effectively increase the inner diameter of the flow channel in the gas well, facilitating shale gas production. Furthermore, since the mounting base 100 is connected to the gas pipe, it can provide a corresponding downhole limiter for the subsequent plunger gas lift process, eliminating the need to deploy the downhole limiter again, saving operational steps, and meeting the process requirements of the plunger gas lift stage. In summary, the use of the downhole throttling structure can simultaneously meet the process requirements of throttling production and the plunger gas lift stage, significantly reducing the time required for the corresponding stage's process layout, improving production efficiency, and reducing process costs.

[0047] like Figure 3 As shown, in some embodiments, the downhole throttle 200 has a second inner cavity 210 coaxially arranged with the first inner cavity, the second inner cavity 210 including a feed end 211; the downhole throttle 200 is also provided with a throttle nozzle 220, the throttle nozzle 220 being sleeved in the feed end 211.

[0048] The structural design of the throttle nozzle 220 can further ensure the throttling effect of the downhole throttle device 200, thereby effectively ensuring the smooth progress of throttling production.

[0049] In some embodiments, the second inner cavity 210 further includes a discharge end 212, which is a frustum structure, and the small diameter end of the discharge end 212 is disposed near the feed end 211.

[0050] Specifically, the discharge end 212 is configured as a frustum structure, which facilitates pressurization when the ball 400 is used to seal the end of the downhole throttle 200. This increases the pressure of the ball 400 at the wellhead, thereby breaking the pin 300 and separating the mounting base 100 from the downhole throttle 200.

[0051] In order to ensure the sealing effect, the diameter of the ball 400 should be within the range of the diameter of the large diameter end and the small diameter end of the discharge end 212.

[0052] In some embodiments, the end of the feed end 211 near the small-diameter end of the discharge end 212 is provided with a stepped surface, which is used to cooperate with the throttle nozzle 220 to limit the relative position of the throttle nozzle 220 in the axial direction of the feed end 211.

[0053] As those skilled in the art should know, when implementing the throttling production process, the downhole pressure is relatively high. By setting the stepped surface, the relative position of the throttling nozzle 220 can be effectively guaranteed, preventing the throttling nozzle 220 from moving towards the wellhead position under pressure.

[0054] In some embodiments, the throttling nozzle 220 includes a nozzle sleeve 221 and a nozzle 222, wherein the nozzle 222 is detachably fitted in the inner cavity of the nozzle sleeve 221, and the nozzle sleeve 221 is fitted in the feed end 211.

[0055] The detachable structural design allows for the effective replacement of nozzle 222, thereby meeting different throttling production needs.

[0056] like Figure 2 As shown, in some embodiments, the first inner cavity includes a guide section 111 and an installation section 112. The downhole throttle 200 is sleeved in the installation section 112. The guide section 111 has a frustum structure, and the small-diameter end of the guide section 111 is located close to the installation section 112.

[0057] By designing the structure of the first inner cavity, it is possible to ensure that the ball 400 can quickly fall into the corresponding sealing position when the ball 400 is dropped, thereby achieving the sealing of the downhole throttling structure and improving the efficiency of production state switching.

[0058] In some embodiments, the inner wall of the cavity slides and seals with the side wall of the downhole choke 200.

[0059] like Figure 4 As shown, this embodiment of the invention also relates to a gas production method based on the above-mentioned downhole throttling structure, comprising the following steps:

[0060] In the initial stage of gas well production, the gas pipe is fixedly connected to the mounting base 100 of the downhole throttling structure to realize production by downhole throttling.

[0061] In the mid-to-late stage of gas well production, when the formation energy decreases and downhole throttling is no longer required, the connection between the downhole throttling device 200 and the mounting base 100 is actively disrupted to separate the downhole throttling device 200 from the mounting base 100 and change the inner diameter of the gas pipe.

[0062] Gas extraction is carried out using a plunger process.

[0063] As should be known to those skilled in the art, the actual switching between the throttling production process and the plunger process can be achieved using existing software, which is prior art and will not be elaborated upon here.

[0064] In some embodiments, actively disrupting the connection between the downhole throttle 200 and the mounting base 100 includes the following steps:

[0065] A ball 400 is inserted into the tracheal cavity through the tracheal inlet. The ball 400 is used to close the end of the downhole throttle 200 near the tracheal inlet.

[0066] A pressurizing device is used to pressurize the inner cavity of the trachea through the trachea inlet, thereby disrupting the connection between the downhole throttle 200 and the mounting base 100, and thus separating the downhole throttle 200 from the mounting base 100.

[0067] Specifically, a pressurizing device is used to pressurize the inner cavity of the gas pipe through the gas pipe inlet, thereby disrupting the connection between the downhole throttle 200 and the mounting base 100, i.e., shearing the pin 300 and breaking it, thus destroying the connection between the two.

[0068] In some embodiments, when the downhole choke structure includes a choke nozzle 220 detachably connected to the downhole choke 200, the size of the choke nozzle 220 is determined based on the hydrate formation prediction of the gas well to be put into production, and then connected to the downhole choke 200 to realize the assembly of the downhole choke 200.

[0069] It should be noted that, as those skilled in the art should know, determining the size of the throttling nozzle 220 based on the predicted hydrate formation in the gas well to be put into production is for the purpose of implementing a suitable throttling production process. The calculation of the size of the throttling nozzle 220 can be combined with professional calculation software to predict the changes in flow rate and temperature before and after downhole throttling, guiding the selection of the size of the throttling nozzle 220. This is a common method in the field and will not be elaborated here.

[0070] Specifically, the calculation results differ for gas wells with different drainage and gas production processes, which directly guides the matching of the tool throttle nozzle 220.

[0071] The above are preferred embodiments of the present invention. Those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions or modifications made by those skilled in the art based on the present invention shall fall within the protection scope of the present invention.

Claims

1. A downhole throttling structure, characterized in that, include: Mounting base (100), the mounting base (100) is used for fixed connection with the trachea, and the mounting base (100) has a first inner cavity; It also includes a downhole choke (200), which is sleeved in the first inner cavity, and the outer wall of the downhole choke (200) is connected to the side wall of the first inner cavity by a pin (300); The pin (300) can break under external force, thereby destroying the connection between the downhole throttle (200) and the mounting base (100). The downhole throttle (200) has a second inner cavity (210) coaxially arranged with the first inner cavity, the second inner cavity (210) including a feed end (211); the downhole throttle (200) is also provided with a throttle nozzle (220), the throttle nozzle (220) being sleeved in the feed end (211); The second inner cavity (210) also includes a discharge end (212), which is a frustum structure, and the small diameter end of the discharge end (212) is located close to the feed end (211); The feed end (211) near the small diameter end of the discharge end (212) is provided with a stepped surface, which is used to cooperate with the throttle nozzle (220) to limit the relative position of the throttle nozzle (220) in the axial direction of the feed end (211); The throttling nozzle (220) includes a nozzle sleeve (221) and a nozzle (222). The nozzle (222) is detachably fitted inside the nozzle sleeve (221), and the nozzle sleeve (221) is fitted inside the feed end (211).

2. The downhole throttling structure according to claim 1, characterized in that, The first inner cavity includes a guide section (111) and an installation section (112). The downhole throttle (200) is fitted in the installation section (112). The guide section (111) has a frustum structure, and the small-diameter end of the guide section (111) is located close to the installation section (112).

3. The downhole throttling structure according to claim 1, characterized in that, The inner wall of the first inner cavity is in sliding sealing fit with the side wall of the downhole throttle (200).

4. A gas production method based on the downhole throttling structure described in any one of claims 1-3, characterized in that, Includes the following steps: In the early stage of gas well production, the gas pipe is fixedly connected to the mounting base (100) of the downhole throttling structure to realize production by downhole throttling. In the middle and late stages of gas well production, when the formation energy decreases and downhole throttling is no longer required, the connection between the downhole throttling device (200) and the mounting base (100) is actively disrupted to separate the downhole throttling device (200) from the mounting base (100) and change the inner diameter of the gas pipe. Gas extraction is carried out using a plunger process.

5. A gas extraction method according to claim 4, characterized in that, Actively disrupting the connection between the downhole throttle (200) and the mounting base (100) includes the following steps: A ball is inserted into the tracheal cavity through the tracheal inlet, the ball being used to seal the end of the downhole choke (200) near the tracheal inlet; A pressurizing device is used to pressurize the inner cavity of the trachea through the trachea inlet, thereby disrupting the connection between the downhole throttle (200) and the mounting base (100) and achieving the separation of the downhole throttle (200) and the mounting base (100).

6. A gas extraction method according to claim 4, characterized in that, When the downhole throttling structure includes a throttling nozzle (220) that is detachably connected to the downhole throttling device (200), the size of the throttling nozzle (220) is determined based on the prediction of hydrate formation in the gas well to be put into production, and it is connected to the downhole throttling device (200) to realize the assembly of the downhole throttling device (200).

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