Gravity-set lateral flow packer

Abstract

The invention is a washable well gravity setting side flow packer used in simple separate layer water injection string, belonging to oil production engineering application technology. The invention has two structures. The first structure shown in figure 1 is composed of upper body 1, center tube 2, big spring 4, liner 9, wash well piston 6, rubber cylinder group 10, lower body 16 and setting shear pin 15. The second structure shown in figure 2 is different from the first structure in that there is no upper side flow channel, but the lower side flow channel is provided with a check valve. The gravity setting side flow packer is used for separate layer water injection, and the water distribution plugger can be set on the center tube of the packer, without using independent water distributor, thus being beneficial to fine layer water injection and convenient for plugger fishing. The packer setting does not need pump truck pressure, but relies on pipe string heavy pressure for setting, and there is no problem of pipe string overload during pipe string lifting, thus simplifying the separate injection process.

Description

TECHNICAL FIELD

[0001] The present application is a packer used on a simple layering water injection string in an oil field, belonging to the technical field of oil production engineering application, and is a downhole tool. BACKGROUND

[0002] In order to reduce the production cost of an oil field, in the aspect of water injection technology, under the premise of meeting the requirements of oil field development on water injection programs, in order to facilitate production management and reduce production cost, the layering water injection string and the matching downhole tool are further optimized to form a simple layering water injection string, and the packer is the most important downhole tool on the layering water injection string, so the packer matched with the string should be researched and designed to solve the following problems:

[0003] At present, the washable hydraulic compression type packer is used on the conventional layering water injection string, which is seated by pressing and unseated by lifting, and in recent years, some people have developed and applied a packer without pressing, but the expansion range of the pressure bearing surface of the packer is limited due to the restriction of the radial size, and the compression amount of the rubber tube group of the packer seated by pressure alone is insufficient, so the ability of the packer to bear the longitudinal pressure difference after being seated is low.

[0004] In addition, the independent water distributor is used between the two-stage packers in the current layering water injection well, and the plug with a water nozzle is installed in the eccentric hole of the water distributor, and due to the length of the water distributor, the distance between the adjacent two packers is difficult to be less than 2.3 meters, which is not conducive to further subdividing layering water injection.

[0005] In addition, the packer used in the subdividing layering water injection has many stages, and the lifting load is large when the string is pulled out, although several types of packers are developed in recent years to avoid overloading of the lifting equipment when the string is pulled out, but the structure is relatively complex, and the single-stage bearing capacity is low, and the packer is easily unseated under high string internal pressure. Previously, the packer used on the well in the oil field has a gravity seating type, which has no overloading problem when the string is pulled out, but is generally used for water plugging in oil wells, and as long as the space of the sleeve ring is sealed, it is not necessary to have a side flow function, and it is not necessary to have a washable well function, and it is not necessary to have a pipe string internal oil prevention function. SUMMARY

[0006] The present application is a packer provided for the simple layering water injection string technology, which has a washable well function. The gravity seating type is adopted, and the string is seated by gravity, so that the work content of calling a pump truck to press and seat when the string is pulled out is avoided. The water distribution plug can be seated in the center pipe of the packer, so that the layering water injection string is provided with an independent water distributor, the height of the water distributor is avoided, which is conducive to subdividing water injection, and the structure of the string is also simplified.

[0007] The technical scheme adopted by the present application to solve the technical problems is as follows:

[0008] Because the simplified stratified injection tubing reduces the packer spacing to facilitate sub-stratified injection and to simplify packer removal and reduce workload, the water distribution packer is located inside the central tube of the packer, thus eliminating the need for a separate eccentric water distributor. The water flowing from the water distribution packer located in the central tube of the packer needs to enter the annulus space through the side wall of the packer and be injected into the formation. Therefore, this type of packer has transverse water flow channels on its side wall leading to the upper and lower annulus spaces of the packer, hence it can be called a side-flow packer.

[0009] When this packer is used in conjunction with a water distribution plug, a transverse fluid passage is provided at the same height on the upper body, the well-washing piston, and the central tube, serving as a water flow channel for injecting water into the oil layer above the packer. A transverse fluid passage is also provided below the rubber sleeve assembly, serving as a water flow channel for injecting water into the oil layer below the packer. The structure is shown in the attached figure. Figure 1 As shown.

[0010] When this type of side-flow packer is only used to seal the oil layer and does not need to be used in conjunction with the water distribution packer, the lateral liquid flow channel above the rubber sleeve assembly is not used; only the lateral liquid flow channel below the rubber sleeve assembly is retained to inject water into a single layer. However, a check valve is installed on this liquid flow channel to prevent oil from entering the oil pipe and causing resistance to the retrieval process. (See attached...) Figure 2 As shown (in the case of using it in conjunction with the water distribution plug, since the water distribution plug already has a single-flow function, there is no need to install single-flow valves in the two lateral flow channels above and below the packer sleeve assembly).

[0011] This type of side-flow packer uses gravity setting, eliminating the need for pressure setting during tubing string installation and simplifying the process. It also ensures that the lifting equipment is not overloaded during tubing string raising in multi-stage applications.

[0012] In addition, a well-washing piston is used between the central tube and the outer shell of the upper body, and a liner is applied to the outside of the central tube to provide a flow space for the well-washing water to flow downwards, thus enabling the well-washing function. At the same time, a spring is used on the well-washing piston to assist in resealing after well washing. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] Figure 1This is a schematic diagram of the basic structure of a dispensing packer with two lateral channels, used in conjunction with a water distribution plugger according to the present invention. It consists of an upper body 1, a central tube 2, a large spring 4, a well-washing piston 6, a liner 9, a rubber sleeve assembly 10, a setting shear pin 15, and a lower body 16. A breather hole 3 is provided at the upper part of the central tube 2, and an upper flow channel hole 5 is provided at the upper-middle part. The upper body 1 and the well-washing piston 6 also have corresponding fluid passage holes at the same height as the flow channel holes 5 in the central tube 2. A well-washing fluid inlet hole 8 is also provided at the lower part of the upper body 1. An outlet hole 13 is provided at the upper part of the lower body 16.

[0015] During application, once the tubing string reaches the predetermined depth and its tail is supported and fixed, the string continues to be lowered. Under the weight pressure of the tubing string above the packer, the setting shear pin 15 is sheared, and the rubber sleeve assembly 10 deforms and expands outward under pressure, sealing the collar space. The lower end of the central tube 2 rests on the inner step of the lower body 16, completing the packer's setting. At this time, the fluid outlet 13 on the upper part of the lower body 16 corresponds to the lower fluid outlet 11 of the liner 9, becoming the fluid outlet channel for the well washing fluid. Meanwhile, the fluid outlet 14 on the lower body 16 corresponds to the fluid outlet 12 of the central tube 2, forming a lower lateral flow channel, thus completing the packer's setting and the formation of each fluid outlet channel.

[0016] During water injection, the water injected into the tubing is distributed through a water distribution plug located on the packer's central tube. Water allocated to the upper layer of the packer flows through the central tube's outlet, then through the corresponding orifices of the well-washing piston 6 and the upper body 1, before entering the annulus space and being injected into the oil layer above the packer. Water allocated to the lower layer of the packer flows through the central tube's outlet 12, then through the lower body 16's outlet 14, entering the annulus space and being injected into the oil layer below the packer.

[0017] During well washing, high-pressure washing water injected from the annulus space enters through the washing inlet 8 of the upper main body 1, pushing the washing piston 6 to compress the spring 4 upwards. It then flows downwards through the inlet 7 of the liner 9, along the annular space between the liner 9 and the central tube 2, and is discharged through the outlet 13 of the lower main body 16 back into the annulus space. Finally, it flows back out through the bottom of the tubing string into the tubing, thus achieving the well washing function. When water injection is resumed after well washing, the washing piston 6 falls back under the pressure difference between the inside and outside of the tube and the push of the spring 4, resealing the inlet 7 of the liner 9.

[0018] When running the tubing string, simply lift the tubing string directly. The pressure on the rubber sleeve assembly 10 is released, and it radially contracts to detach from the wellbore, thus completing the unsealing of the packer.

[0019] Figure 2This is a schematic diagram of the basic structure of a single-injection packer used for single-layer water injection with only one lateral injection channel in this invention. Unlike the aforementioned multi-injection packer, it lacks the lateral fluid flow channel above the rubber sleeve assembly. However, it has a valve ball 17 and a small spring 14 on the lower fluid flow channel. Water in this channel pushes open the valve ball, rises, and enters the outlet hole 13 of the lower body 16 for discharge. Due to the function of the check valve, oil ingress prevention within the oil pipe is achieved.

Claims

1. A gravity-set side-flow packer, used for two-layer injection, is composed of an upper body (1), a central tube (2), a large spring (4), a liner (9), a well-washing piston (6), a rubber sleeve assembly (10), a setting shear pin (15), and a lower body (16); a vent hole (3) is opened at the upper part of the central tube (2), and an upper flow channel hole (5) is opened at the middle and upper part; the upper body (1) and the well-washing piston (6) are also provided with corresponding fluid passage holes at the same height as the upper flow channel hole (5) of the central tube (2); a well-washing fluid inlet hole (8) is also provided at the lower part of the upper body (1); and a first outlet hole (13) and a second outlet hole (14) are provided at the upper part of the lower body (16). Its features are: When used as a packer in conjunction with a plug, the upper flow channel hole (5) of the central tube (2) and the hole at the same height between the well washing piston (6) and the upper body (1) form a lateral flow channel; after the packer is set, the central tube (2) falls onto the inner step of the lower body (16), the lower outlet hole (11) of the liner (9) and the outlet hole one (13) of the lower body (16) form a well washing fluid discharge channel; at the same time, the outlet hole (12) on the central tube (2) and the outlet hole two (14) on the lower body (16) form another lateral fluid flow channel.

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