A large bore deep penetrating composite perforating completion structure for shallow oil sand reservoirs

Abstract

This invention relates to the field of perforation reinforcement technology, specifically to a large-diameter, deep-penetration composite perforation completion structure for shallow oil sand reservoirs. It includes an embedding assembly comprising a liner. The surface of the liner is uniformly and fixedly covered with several barbed anchor claws. The inner wall of the liner is coated with a low-melting-point alloy film. When the perforating projectile is launched, the low-melting-point alloy film coated on the inner wall of the liner melts instantaneously, releasing the folding constraint on the liner. The impact force of the launched perforating projectile pushes the liner radially to expand, forcing it to penetrate the loose sandstone of the perforation wall. Subsequently, the anchor claws on the liner surface penetrate the perforation wall, fixing the liner within the entire length of the perforation, preventing the formation of oil sand plugs inside the perforation, thereby avoiding the inability of injected fluid to enter the deep part of the perforation and preventing completion failure.

Description

Technical Field

[0001] This invention relates to the field of perforation reinforcement technology, and more specifically, to a large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs. Background Technology

[0002] Shallow oil sands reservoirs are characterized by shallow burial, low formation temperature, high oil pour point, loose reservoir cementation, high clay mineral content, and strong water sensitivity. In the development of these reservoirs, a combined perforation completion technique using large-diameter and deep-penetration perforations is typically employed to expand the drainage radius, reduce production pressure differential, and minimize sand production. Specifically, this technique first utilizes large-diameter perforating cartridges to create a large near-wellbore channel, and then implements deep-penetration perforations at the same depth, forming the final radial perforation system.

[0003] However, after the perforating shell detonates, the loose sandstone particles on the inner wall of the perforation channel are prone to detachment under stress release and high-temperature gas impact. Simultaneously, the formation temperature of this reservoir is typically lower than the freezing point of the oil sands, causing the oil sands seeping from the pores to quickly lose their fluidity. The detached sand particles rapidly mix and cement with the solidified oil sands at the inlet section of the perforation channel, forming a dense oil sand plug with high mechanical strength. Because the inner wall of the perforation completion equipment is exposed after the perforation operation, it is prone to form an oil-sand plug, and the formation process of the oil-sand plug is uninterrupted. The plug forms extremely quickly, usually completely sealing the inlet section of the wellbore within minutes to tens of minutes after the perforation operation is completed; In this situation, the microbial fluid, microemulsion, or thermal fluid subsequently injected for in-situ oil sand development is blocked by the oil sand plug at the wellhead. The injected fluid cannot penetrate deep into the well, nor can it dissolve or destroy the plug; it can only circulate short-circuit near the wellbore or return to the surface. Consequently, the well completion process cannot establish effective formation communication, the pre-designed injection and production process cannot be implemented, the reservoir utilization range is severely compressed, and the production capacity is far below the design target. In view of this, this invention proposes a large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs. Summary of the Invention

[0004] The purpose of this invention is to provide a large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs, in order to solve the problem mentioned in the background art where an oil sand plug quickly forms at the inlet of the perforation channel, blocking the subsequent injection of fluid into the reservoir and causing completion failure.

[0005] To address the aforementioned issues, a large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs is provided, comprising a perforation gun, wherein the perforation end of the perforation gun is provided with an embedding component, the embedding component comprising a liner, wherein the inner and outer diameters of the liner and the perforation gun are the same. The liner is made of shape memory alloy, and the initial state of the liner is a tightly folded shape; The surface of the liner is fixedly and evenly distributed with several barbed No. 1 anchor claws. In the initial state, the No. 1 anchor claws are attached to the outer wall of the liner, and the tip of the No. 1 anchor claws faces the side closer to the perforation gun. The inner wall of the liner is coated with a low-melting-point alloy film.

[0006] When the perforating projectile is fired, the internal temperature of the perforating gun and the liner rises rapidly as the projectile is fired. At this moment, the low-melting-point alloy film coated on the inner wall of the liner is instantly melted, releasing the folding constraint on the liner. This allows the liner to be released from its folded state. The impact force of the perforating projectile pushes the liner to expand radially, forcing it to penetrate the loose sandstone of the borehole wall. After the liner penetrates the loose sandstone of the borehole wall, the No. 1 anchor claw expands in all directions and penetrates the borehole wall, fixing the liner within the entire length of the borehole. This prevents the formation of oil sand plugs inside the borehole, thus avoiding the inability of injected fluid to enter the deep part of the borehole and causing well completion failure.

[0007] As a further improvement to this technical solution, the liner, after expansion, takes the shape of a cylinder that matches the penetration depth of the perforation. The liner is provided with multiple guide grooves, and the guide grooves take the shape of a V after the liner expands.

[0008] After the liner expands and embeds into the channel, the flow channel forms multiple continuous flow channels parallel to the well axis.

[0009] As a further improvement to this technical solution, the inside of the guide channel is fixedly provided with multiple protrusions for capturing tiny sand particles.

[0010] When sand particles or solidified oil sand that have fallen off the inner wall of the channel move toward the inlet section, the guide channel intercepts large-diameter particles between the protrusions through the bottom structure, while keeping the flow section of the top of the liner and the side wall of the liner from being completely blocked, ensuring that trace fluids and subsequently injected chemicals can continue to pass through the liner.

[0011] As a further improvement to this technical solution, an impact block is slidably arranged inside the launching tube, and a pre-compressed pressure spring is fixedly arranged at the end of the impact block away from the embedded component, and the pressure spring is fixedly arranged inside the launching tube.

[0012] When the pressure spring is released, it pushes the impact block out of the inside of the launch tube.

[0013] As a further improvement to this technical solution, a temperature-sensitive locking pin is provided at the end of the impact block away from the pressure spring. The temperature-sensitive locking pin is locked inside the launching tube and is used to limit the impact block in the initial state.

[0014] Under the limiting action of the temperature-sensitive locking pin, the pressure spring remains compressed, and the impact block cannot slide out from the inside of the firing tube.

[0015] As a further improvement to this technical solution, a heat-conducting block is provided on the lower side of the temperature-sensitive locking pin. The heat-conducting block is fixedly disposed between the perforating gun, the connecting sleeve and the firing tube. One end of the heat-conducting block is in contact with the bottom of the temperature-sensitive locking pin, and the other end of the heat-conducting block is disposed inside the perforating gun.

[0016] When the perforating projectile is fired, the temperature inside the perforating gun rises rapidly. The heat inside the perforating gun is transferred to the temperature-sensitive locking pin through the heat-conducting block, and gradually melts the temperature-sensitive locking pin. After the temperature-sensitive locking pin is melted, the pressure spring, which is in a compressed state, is immediately released and pushes out the impact block quickly. Since it takes a certain amount of time for the temperature-sensitive locking pin to melt, this action is performed after the perforation is completed.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this large-diameter deep-penetration composite perforation completion structure used in shallow oil sand reservoirs, when the perforating projectile is fired, the low-melting-point alloy film coated on the inner wall of the liner is instantly melted, releasing the folding constraint on the liner. This allows the liner to be released from its folded state. The impact force of the perforating projectile pushes the liner to expand radially, forcing the liner to penetrate into the loose sandstone of the borehole wall. Subsequently, the No. 1 anchor claw on the surface of the liner penetrates into the borehole wall, fixing the liner within the entire length of the borehole. This prevents the formation of oil sand plugs inside the borehole, thereby avoiding the inability of injected fluid to enter the deep part of the borehole and causing completion failure.

[0018] 2. In this large-diameter deep-penetration composite perforation completion structure used in shallow oil sand reservoirs, the temperature inside the perforating gun rises instantaneously when the perforating projectile is fired. The high temperature is transferred to the temperature-sensitive locking pin through the heat-conducting block and gradually melts it. After the temperature-sensitive locking pin is melted, the pressure spring in the compressed state quickly pushes out the impact block and impacts the force transmission block. This impact force is transmitted to the liner through the force transmission block and the collar, causing the liner to vibrate and dislodging the oil sand plug that has begun to condense, further reducing the probability of oil sand plug formation inside the channel. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the end structure of the perforating gun of the present invention; Figure 3 This is a schematic diagram of the liner of the present invention under compression. Figure 4 This is a schematic diagram of the structure of the liner in the expanded state of the present invention; Figure 5 This is a cross-sectional view of the liner of the present invention under expanded state; Figure 6For the present invention Figure 5 Enlarged view of the structure at point A in the middle; Figure 7 This is a cross-sectional view of the transmitting tube and connecting sleeve structure of the present invention; Figure 8 For the present invention Figure 7 Enlarged view of the structure at point B in the middle; Figure 9 This is a schematic diagram of the locking component and the embedding component of the present invention; Figure 10 For the present invention Figure 9 Enlarged view of the structure at point C.

[0020] The meanings of the labels in the diagram are as follows: 1. Perforation gun; 2. Embedded assembly; 21. Liner; 22. Anchor claw No. 1; 23. Flow guide channel; 24. Protrusion; 3. Impact assembly; 31. Launch tube; 32. Connecting sleeve; 33. Impact block; 34. Pressure spring; 35. Temperature-sensitive locking pin; 36. Heat-conducting block; 4. Locking assembly; 41. Collar; 42. Wedge block; 43. No. 2 anchor claw; 44. Pin; 5. Force transmission block. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," 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 limitations on this invention.

[0023] Example 1: First, please refer to Figure 1 and Figure 9The purpose of this embodiment is to provide a large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs, including a perforating gun 1. The perforating end of the perforating gun 1 is provided with an embedding component 2. The embedding component 2 includes a liner 21. Both ends of the embedding component 2 are provided with locking components 4. The locking component 4 includes a collar 41 fixedly connected to the end of the liner 21. The collar 41 near one end of the perforating gun 1 is inserted into the side wall of the perforating gun 1, and its inner and outer diameters are the same as those of the perforating gun 1, so as to ensure that the perforating bullet can be ejected from the collar 41. Furthermore, a plurality of pins 44 are inserted between the collar 41 near one end of the perforating gun 1 and the side wall of the perforating gun 1 to connect the perforating gun 1 and the collar 41. The pins 44 can be pulled out from the perforating gun 1 and the collar 41. After the pins 44 are pulled out, the collar 41 can be pulled out from the perforating gun 1 so that the collar 41 can be pulled out after the perforation is completed.

[0024] For further details, please refer to Figures 1-4 Align the collar 41 at the other end of the liner 21 with the perforation hole position, and fire the perforation projectile by operating the perforation gun 1. As the perforation gun 1 is a common existing technology, its structure and function will not be described in this solution. In order to make the perforation projectile be fired smoothly from the liner 21, the inner and outer diameters of the liner 21 and the perforation gun 1 are the same. Furthermore, the liner 21 is made of shape memory alloy. The initial state of the liner 21 is a tightly folded shape. The inner wall of the liner 21 is coated with a low melting point alloy film. When the perforating projectile is fired, the internal temperature of the perforating gun 1 and the liner 21 rises rapidly as the perforating projectile is fired. At this time, the low melting point alloy film coated on the inner wall of the liner 21 is instantly melted, releasing the folding constraint on the liner 21. This allows the liner 21 to be released from its folded state. The impact force of the perforating projectile pushes the liner 21 to expand radially, forcing the liner 21 to penetrate into the loose sandstone of the channel wall. After expansion, the liner 21 takes the shape of a cylinder that matches the penetration depth of the perforating projectile. Secondly, several barbed anchor claws 22 are evenly arranged on the surface of the liner 21. In the initial state, the anchor claws 22 are attached to the outer wall of the liner 21, and the tips of the anchor claws 22 face the side closer to the perforating gun 1. After the liner 21 penetrates the loose sandstone of the channel wall, the anchor claws 22 expand in all directions and penetrate into the channel wall, fixing the liner 21 within the entire length of the channel, preventing the formation of oil sand plugs inside the channel, thereby avoiding the inability of injected fluid to enter the deep part of the channel and causing well completion failure.

[0025] To prevent the ends of the liner 21 from shifting position after penetrating the injection channel, please refer to... Figures 9-10Multiple wedges 42 are evenly arranged on the side wall of the collar 41. Several second anchor claws 43 are fixed on the side of the wedges 42 away from the side wall of the collar 41. The tips of each second anchor claw 43 are facing the side closer to the perforating gun 1. The collars 41 at both ends of the liner 21 are inserted into the loose sandstone of the duct wall along with the liner 21. Then, several second anchor claws 43 are inserted into the duct wall at both ends of the liner 21 to fix the two ends of the liner 21 and prevent the two ends of the liner 21 from displacing.

[0026] Secondly, please refer to Figures 4-6 The liner 21 has multiple guide channels 23 inside, and the guide channels 23 are V-shaped after the liner 21 expands. Multiple protrusions 24 are fixedly installed inside the guide channels 23 to capture small sand particles. After the liner 21 expands and is embedded into the channel, the guide channels 23 form multiple continuous flow channels parallel to the well axis. When sand particles or solidified oil sand that fall off the inner wall of the channel move towards the inlet section, the guide channels 23 intercept large-diameter particles between the protrusions 24 through the bottom structure, while keeping the flow section of the top and side wall of the liner 21 from being completely closed, ensuring that the trace fluid and the subsequently injected chemical agent can still continuously pass through the liner 21.

[0027] For further details, please refer to Figures 2-9 An impact component 3 is provided at one end of the embedded component 2 near the perforating gun 1. The impact component 3 includes a firing tube 31, which is located on the upper side of the perforating gun 1. The firing tube 31 is open at one end near the embedded component 2 and closed at the other end. A connecting sleeve 32 is wrapped around the firing tube 31 and the perforating gun 1 to fix the firing tube 31 on the upper side of the perforating gun 1. An impact block 33 is slidably arranged inside the firing tube 31. A pre-compressed pressure spring 34 is fixedly arranged at one end of the impact block 33 away from the embedded component 2. The pressure spring 34 is fixedly arranged inside the firing tube 31. The pressure spring 34 is in a compressed state in the initial state. When it is released, it pushes the impact block 33 out of the firing tube 31. Furthermore, a temperature-sensitive locking pin 35 is provided at the end of the impact block 33 away from the pressure spring 34. The temperature-sensitive locking pin 35 is locked inside the firing tube 31. The temperature-sensitive locking pin 35 is used to limit the impact block 33 in the initial state to prevent the pressure spring 34 from pushing the impact block 33 out in the stationary state. A heat-conducting block 36 is provided on the lower side of the temperature-sensitive locking pin 35. The heat-conducting block 36 is fixedly disposed between the perforating gun 1, the connecting sleeve 32 and the firing tube 31. One end of the heat-conducting block 36 is in contact with the bottom of the temperature-sensitive locking pin 35. The other end of the heat-conducting block 36 is located inside the perforating gun 1. When the perforating bullet is fired, the temperature inside the perforating gun 1 rises rapidly. The temperature-sensitive locking pin 35 is made of a low-melting-point alloy. The heat inside the perforating gun 1 is transferred to the temperature-sensitive locking pin 35 through the heat-conducting block 36, and the temperature-sensitive locking pin 35 is gradually melted. After the temperature-sensitive locking pin 35 is melted, the pressure spring 34, which is in a compressed state, is immediately released and the impact block 33 is quickly pushed out. Since it takes a certain amount of time for the temperature-sensitive locking pin 35 to melt, this action is performed after the perforation is completed. A force transmission block 5 corresponding to the position of the impact block 33 is fixedly installed on the upper side of the collar 41 near one end of the perforating gun 1. After the impact block 33 is pushed out, it impacts the force transmission block 5. The impact force generated by the impact block 33 on the force transmission block 5 is transmitted to the liner 21 through the force transmission block 5 and the collar 41, causing the liner 21 to vibrate and shake off the oil sand plug that has begun to condense, further reducing the probability of oil sand plug formation inside the channel. Then, each pin 44 is removed and the perforating gun 1 is pulled out.

[0028] Therefore, based on the above, the working principle of this invention can be summarized as follows: After aligning the liner 21 with the perforation position, the perforation gun 1 is used to fire the perforation projectile. When the perforation projectile passes through the liner 21, the high temperature melts the low-melting-point alloy film on the inner wall of the liner 21. Subsequently, the liner 21 rapidly expands radially and penetrates the perforation channel as the perforation projectile is fired. It is then fixed within the entire length of the channel by the reinforcement of the first anchor claw 22 and the second anchor claw 43, preventing the formation of oil sand plugs inside the channel and thus avoiding the injection of fluid. Unable to penetrate deep into the borehole, resulting in well completion failure, the perforating gun, while being ejected, transfers some of its heat through the heat-conducting block 36 to the temperature-sensitive locking pin 35, gradually melting the temperature-sensitive locking pin 35. After the temperature-sensitive locking pin 35 is melted, the pressure spring 34 pushes out the impact block 33, which then impacts the force transmission block 5. The force transmission block 5 and the collar 41 transmit the impact force to the liner 21, causing the liner 21 to vibrate and dislodging the oil sand plug that has begun to condense, ensuring that the injected fluid can smoothly enter deep into the borehole.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs, comprising a perforation gun (1), characterized in that: The perforating gun (1) is provided with an embedding component (2) at the perforating end. The embedding component (2) includes a liner (21), and the inner and outer diameters of the liner (21) are the same as those of the perforating gun (1). The liner (21) is made of shape memory alloy, and the initial state of the liner (21) is a tightly folded shape; The surface of the liner (21) is fixedly and evenly arranged with several barbed No. 1 anchor claws (22). In the initial state, the No. 1 anchor claws (22) are attached to the outer wall of the liner (21), and the tip of the No. 1 anchor claws (22) faces the side closer to the perforating gun (1). The inner wall of the liner (21) is coated with a low-melting-point alloy film.

2. The large-bore deep-penetration composite perforation completion structure for shallow oil sand reservoirs of claim 1, characterized in that: The liner (21) expands to a cylindrical shape that matches the penetration depth of the perforation. The liner (21) has multiple guide grooves (23) inside, and the guide grooves (23) are V-shaped after the liner (21) expands.

3. The large-bore deep-penetration composite perforating completion structure for shallow oil sand reservoirs of claim 2, characterized in that: The guide channel (23) is fixedly provided with multiple protrusions (24) for capturing tiny sand particles.

4. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 1, characterized in that: The embedded component (2) is provided with an impact component (3) at one end near the perforating gun (1). The impact component (3) includes a firing tube (31) which is located on the upper side of the perforating gun (1). The transmitting tube (31) is open at one end near the embedded component (2) and closed at the other end.

5. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 4, characterized in that: The firing tube (31) and the perforating gun (1) are covered with a connecting sleeve (32) for fixing the firing tube (31) to the upper side of the perforating gun (1).

6. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 5, characterized in that: An impact block (33) is slidably disposed inside the firing tube (31). A pre-compressed pressure spring (34) is fixedly disposed at the end of the impact block (33) away from the embedded component (2). The pressure spring (34) is fixedly disposed inside the firing tube (31).

7. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 6, characterized in that: The impact block (33) is provided with a temperature-sensitive locking pin (35) at the end away from the pressure spring (34). The temperature-sensitive locking pin (35) is locked inside the firing tube (31) and is used to limit the impact block (33) in the initial state.

8. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 7, characterized in that: A heat-conducting block (36) is provided on the lower side of the temperature-sensitive locking pin (35). The heat-conducting block (36) is fixedly disposed between the perforating gun (1), the connecting sleeve (32) and the firing tube (31). One end of the heat-conducting block (36) is in contact with the bottom of the temperature-sensitive locking pin (35), and the other end of the heat-conducting block (36) is disposed inside the perforating gun (1).

9. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 1, characterized in that: Both ends of the embedded component (2) are provided with locking components (4). The locking component (4) includes a collar (41) fixedly connected to the end of the liner (21). The collar (41) near the end of the perforating gun (1) is inserted into the side wall of the perforating gun (1), and its inner and outer diameters are the same as those of the perforating gun (1). A force transmission block (5) corresponding to the position of the impact block (33) is fixedly installed on the upper side of the collar (41) near the end of the perforating gun (1).

10. The large-diameter deep-penetration composite perforation completion structure for shallow oil sand reservoirs according to claim 9, characterized in that: Multiple wedges (42) are evenly arranged on the side wall of the collar (41). Several second anchor claws (43) are fixed on the side of the wedges (42) away from the side wall of the collar (41). The tips of each second anchor claw (43) face the side closer to the perforating gun (1). Multiple pins (44) are inserted between the collar (41) near one end of the perforating gun (1) and the side wall of the perforating gun (1) to connect the perforating gun (1) and the collar (41).

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