CN207686692U - Split injection string for horizontal well - Google Patents

Abstract

The utility model provides a horizontal well is with dividing tubular column of annotating. The tubing of the separate injection tubing string is sequentially provided with a first packer, a water distributor and a second packer from a well head to a well bottom direction, the first packer and the water distributor are positioned at the vertical section of the horizontal well, and the second packer is positioned at the horizontal section of the horizontal well; the oil pipe, the first packer, the water distributor and the second packer are accommodated in the casing; the casing pipe is provided with a first perforation channel and a second perforation channel which are respectively communicated with the first oil layer and the second oil layer; the water distributor comprises a working barrel and a flow distribution mechanism put in the working barrel, the working barrel is provided with a first water outlet communicated with the first perforation channel and the flow distribution mechanism, a second water outlet is formed in one end, far away from a wellhead, of the flow distribution mechanism, and the flow distribution mechanism is used for controlling the flow of working liquid of the first water outlet and the second water outlet. The utility model provides a horizontal well is with dividing the tubular column once to throw and drag for adjustable two-layer flow, has shortened operating cycle, has improved the exploitation efficiency of oil.

Description

Split injection string for horizontal well

technical field

The utility model relates to the technical field of oil production in oilfields, in particular to a separate injection pipe string for horizontal wells for layered water injection and acidification.

Background technique

In the process of oilfield development, with the exploitation and production of the oilfield, the formation pressure of the oilfield gradually decreases, which makes the recovery rate of crude oil decrease. In order to maintain the formation pressure and maintain the vigorous production capacity of the oil well, it is necessary to supplement the formation pressure with water injection. During the water injection process, due to the difference in physical properties of the reservoir, the water injection pressure and water absorption index of each water injection layer are different, it is urgent to carry out layered water injection to adjust the contradiction between layers; and the incompatibility of water injection water quality and formation fluid and other factors, As a result, the oil displacement effect of water injection becomes worse, so after a period of water injection, acidification is generally required to remove plugs.

In the prior art, vertical wells or wells with small inclination generally use conventional eccentric layered water injection strings for water injection and acidification. The conventional eccentric layered water injection string is from top to bottom, and the tubing is sequentially connected with telescopic pipe, hydraulic anchor, packer, first eccentric water distributor, packer, second eccentric water distributor, and check valve. Wherein, the first eccentric water distributor and the second eccentric water distributor may be arranged in the inclined well section. When in use, water or acidizing fluid passes through oil pipe, telescopic tube, hydraulic anchor, packer and the outlet hole of the first eccentric water distributor in sequence, enters the first water injection layer or acidizing layer, and part of the water or acidizing fluid passes through the second The main channel of the first eccentric water distributor, the packer and the outlet hole of the second eccentric water distributor enter the second water injection layer or acidification layer to realize layered water injection or acidification. The plug of the eccentric water distributor is installed in the lateral eccentric hole of the central channel, and the size of the nozzle is adjusted by pulling the plug to control the water injection volume of different layers.

In the process of measurement and adjustment, it is necessary to perform multiple fishing operations to adjust the eccentric plugs of the first and second eccentric water distributors. If the slope of the water injection well is large, the success rate of fishing is low and the workload of fishing is large, while the double-step Horizontal wells or horizontal wells have a lower success rate of injection and fishing, which affects the efficiency of oil extraction.

Utility model content

The utility model provides a separate injection pipe string for horizontal wells to overcome the problems of heavy fishing workload and low success rate of the existing separate injection pipe strings.

The utility model provides a split injection pipe string for a horizontal well, comprising: oil pipe, casing, a first packer, a water distributor and a second packer; the oil pipe is sequentially installed with the first packer from the wellhead to the bottom of the well , water distributor and second packer, and the first packer and water distributor are located in the vertical section of the horizontal well, and the second packer is located in the horizontal section of the horizontal well; the first packer and the second packer will A horizontal well is divided into a non-productive layer near the wellhead, a second oil layer near the bottom of the well, and a first oil layer between the non-productive layer and the second oil layer; tubing, first packer, water distributor, and second packer It is accommodated in the casing; the casing is provided with the first perforation channel and the second perforation channel respectively connected with the first oil layer and the second oil layer; the water distributor includes a work cylinder and a flow distribution mechanism put in the work cylinder, There is a first water outlet connected to the first perforation channel and the flow distribution mechanism. The end of the flow distribution mechanism away from the wellhead is formed with a second water outlet. The flow distribution mechanism is used to control the working fluid of the first water outlet and the second water outlet. flow.

The dispensing string for horizontal wells as described above, wherein the flow distribution mechanism includes an upper filter element and a lower filter element; the upper filter element includes an upper channel and a first channel opened on the side of the upper channel, and the first channel communicates with the first water outlet ; A first faucet is arranged in the upper channel to control the flow of the first channel; the lower filter element includes a lower channel and a second channel opened on the side of the lower channel, and the annular space between the second channel and the working cylinder and the upper filter element connected; the lower channel is provided with a second nozzle for controlling the flow of the lower channel; the second water outlet is set at the end of the lower channel away from the upper filter element.

The distributing pipe string for horizontal wells as described above, wherein the axis of the first nozzle is provided with a first flow hole for communicating with the upper channel and the first channel; the axis of the second nozzle is provided with a second flow hole. The hole is used to communicate with the lower channel and the second water outlet.

The dispensing string for horizontal wells as described above, wherein, the end of the working cylinder near the wellhead is provided with an upper joint for connecting with the tubing; the end of the working cylinder near the bottom of the well is provided with a lower joint for connecting with the tubing.

The above-mentioned injection string for horizontal wells also includes a centralizer group, which is used to make the second packer located at the axial center of the casing; the centralizer group includes a first centralizer and a second centralizer; the first The centralizer is located at one end of the second packer close to the wellhead, and the second centralizer is located at the end of the second packer close to the well bottom.

The above-mentioned split injection string for horizontal wells, wherein the second packer is a self-checking packer.

The above-mentioned dispensing string for horizontal wells also includes a first hydraulic anchor and a second hydraulic anchor; the first hydraulic anchor is set at the end of the first packer close to the wellhead; the second hydraulic anchor is set at the first centralizer The end near the mouth of the well.

The dispensing pipe string for horizontal wells as described above also includes a first telescopic pipe and a second telescopic pipe; the first telescopic pipe is arranged at the end of the first hydraulic anchor close to the wellhead; the second telescopic pipe is arranged at the end of the water distributor near the bottom of the well One end, and the second telescoping tube is located on the side of the first perforation tunnel close to the wellhead.

The dispensing string for horizontal wells as described above also includes a first hand-off joint and a second hand-off joint; the first hand-off joint is arranged between the first hydraulic anchor and the first telescopic pipe; the second hand-off joint Set at the end of the second hydraulic anchor close to the wellhead.

The above-mentioned split injection string for horizontal wells also includes a sand control screen and a shoe plug; the shoe plug is set at the end of the tubing near the bottom of the well; the sand control screen is set at the end of the shoe plug away from the bottom of the well .

In the utility model, the split injection pipe string for the horizontal well divides the horizontal well into the non-production layer near the wellhead, the second oil layer near the bottom of the well, and the non-production layer and the second oil layer through the first packer and the second packer. For the first oil layer between the oil layers, the casing is provided with the first perforation channel and the second perforation channel respectively connected with the first oil layer and the second oil layer, and the working cylinder of the water distributor is provided with the first perforation channel and the flow distribution channel. The first water outlet connected with the mechanism, the end of the flow distribution mechanism away from the wellhead forms a second water outlet, the flow distribution mechanism controls the flow of the working fluid from the first water outlet and the second water outlet, and then controls the flow out of the first perforation tunnel and the second water outlet. The working fluid flow rate of the second perforation channel realizes layered water injection and acidification, and the working fluid flow rate of two layers can be measured and adjusted at one time, reducing the operating procedures, shortening the operating cycle, and improving the efficiency of oil extraction.

Description of drawings

The above and other objects, features and advantages of the embodiments of the present invention will become more comprehensible through the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present utility model will be described by way of example and non-limitation, wherein:

Fig. 1 is the structural representation of the utility model horizontal well with dispensing pipe string;

Fig. 2 is a sectional view of the water distributor in Fig. 1;

Fig. 3 is a schematic diagram of the flow direction of the working fluid of the water distributor in Fig. 1 .

Explanation of reference signs:

1: Oil pipe; 2: Casing;

3: The first telescopic tube; 4: The first drop joint;

5: the first hydraulic anchor; 6: the first packer;

7: water distributor; 71: outer cylinder;

711: the first water outlet; 712: the upper joint;

72: the first filter element; 721: the third channel;

722: first channel; 723: filter hole;

724: fishing department; 725: annular space;

73: the second filter element; 731: the fourth channel;

732: the second channel; 733: the second water outlet;

74: intermediate filter element; 741: upper channel;

742: lower channel; 743: partition layer;

75: inner cylinder; 751: flow channel;

752: lower joint; 76: first faucet;

761: the first flow hole; 77: the second faucet;

771: second flow hole; 78: upper channel;

79: lower channel; 8: second telescopic tube;

9: The second drop joint; 10: The second hydraulic anchor;

11: the first centralizer; 12: the second packer;

13: Second centralizer; 14: Sand control screen;

15: plug; 16: first perforation tunnel;

17: Second perforation tunnel; 18: Oil casing annulus;

19: non-production layer; 20: first oil layer;

21: second oil layer; 22: ball seat.

Detailed ways

Oil extraction is the process of excavating and extracting oil in reservoirs that store oil. Oil extraction can be roughly divided into three stages:

Primary oil recovery usually relies on natural energy such as edge water drive, gravity, and natural gas expansion. At this stage, natural energy is mainly used to lift the oil in the reservoir to the wellhead through oil pipes; however, with the continuous output of crude oil and natural gas, The pressure of the oil layer gradually decreases, so that the oil well cannot realize self-flowing production, and the oil recovery rate at this stage is only 15%-20% on average, and most of the recoverable reserves remain underground.

Secondary oil recovery is mainly to increase the pressure of the oil layer through water injection, gas injection, etc., so that the oil well can continue to produce oil after the oil well stops blowing. Among them, water injection production is to inject water into the reservoir through special injection wells to maintain or restore the reservoir pressure, so that the reservoir will form a strong driving force to improve the recovery of the reservoir; gas injection production is mainly to use the injected gas Viscosity reduction, swelling, miscibility, molecular diffusion, etc. can reduce the interfacial tension, increase the permeability, and then increase the oil recovery rate of the oil field. Due to the heterogeneity of the formation, the injected fluid usually flows to the oil well along the path of less resistance, while the oil in the area of relatively greater resistance cannot be extracted, so the recovery rate of the secondary oil recovery stage is still limited.

Tertiary oil recovery mainly uses various physical and chemical methods to change the viscosity of crude oil and its adsorption to rocks, thereby increasing the flow capacity of crude oil and further enhancing oil recovery. Tertiary oil recovery methods mainly include thermal oil recovery, chemical flooding, miscible flooding, microbial flooding, etc.

During the water injection process, the rust generated on the inner wall of the water injection pipeline, the mechanical impurities in the water, and the reproduction of microorganisms, etc., enter the pores of the oil layer. In the pores of the rock near the bottom of the well, the initial liquid drainage was not complete, resulting in some blockages remaining in the original channels, affecting the flow of injected water. Therefore, it is necessary to take measures to increase the water absorption of the reservoir. At this stage, acidification is generally used for plugging removal.

The acidizing process of the oil layer is to inject the acid liquid into the oil layer to be treated through the high-pressure injection equipment on the ground, let the acid liquid contact with the oil layer to cause chemical dissolution, dissolve the blockage in the formation, and dredge the pores in the oil layer through the corrosion of strong acid. Oil, gas, water and other fluids in the oil layer flow smoothly. At the same time, use the acid liquid to contact the pollution near the bottom of the production well and water injection well, eliminate the clogging substances in the pores, expand the original pores of the formation, reduce the resistance of oil flow into the well or water injection resistance, improve the permeability of the oil layer, and reach the water injection well purpose of adding.

In the prior art, vertical wells or wells with small inclination generally use conventional eccentric layered water injection strings for water injection and acidification. The conventional eccentric layered water injection string is from top to bottom, and the tubing is sequentially connected with telescopic pipe, hydraulic anchor, packer, first eccentric water distributor, packer, second eccentric water distributor, and check valve. Wherein, the first eccentric water distributor and the second eccentric water distributor may be arranged in the inclined well section. When in use, water or acidizing fluid passes through oil pipe, telescopic tube, hydraulic anchor, packer and the outlet hole of the first eccentric water distributor in sequence, enters the first water injection layer or acidizing layer, and part of the water or acidizing fluid passes through the second The main channel of the first eccentric water distributor, the packer and the outlet hole of the second eccentric water distributor enter the second water injection layer or acidification layer to realize layered water injection or acidification. The plug of the eccentric water distributor is installed in the lateral eccentric hole of the central channel, and the size of the nozzle is adjusted by pulling the plug to control the water injection volume of different layers.

In the process of measurement and adjustment, it is necessary to perform multiple fishing operations to adjust the eccentric plugs of the first and second eccentric water distributors. If the slope of the water injection well is large, the success rate of fishing is low, and the workload of fishing is large, which will affect the oil production. mining efficiency. Affected by factors such as water injection and acidizing pressure fluctuations, the pipe string is prone to expansion and contraction, resulting in the unsealing of the packer. Affected by the well deviation, the pipe string wears seriously on key parts such as the packer during the process of entering the well, which easily leads to the failure of the packer. For this reason, the utility model provides a layered water injection and acidizing string suitable for double-step horizontal wells and horizontal wells.

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

It should be understood that, in the present utility model, the orientation word "upper" refers to the side near the wellhead, and the orientation word "down" refers to the side near the bottom of the well. In addition, in the utility model, in the stratified water injection operation, the working fluid refers to water; in the stratified acidification process, the working fluid refers to the acidizing fluid, but the utility model does not specifically limit the type of acidizing fluid.

Fig. 1 is a structural schematic diagram of a dispensing string for a horizontal well of the present invention; Fig. 2 is a cross-sectional view of the water distributor in Fig. 1; Fig. 3 is a schematic diagram of the flow of working fluid in the water distributor in Fig. 1 . Referring to FIG. 1 to FIG. 3 , the dispensing string for horizontal well provided in this embodiment includes: tubing 1 , casing 2 , first packer 6 , water distributor 7 and second packer 12 .

Specifically, the tubing 1 is sequentially installed with a first packer 6, a water distributor 7 and a second packer 12 from the wellhead to the bottom of the well, and the first packer 6 and the water distributor 7 are located in the vertical section of the horizontal well. The second packer 12 is located in the horizontal section of the horizontal well; the first packer 6 and the second packer 12 separate the horizontal well into a non-production layer 19 near the wellhead, a second oil layer 21 near the bottom of the well, and a non-production layer located in the non-production layer. The first oil layer 20 between the layer 19 and the second oil layer 21; the tubing 1, the first packer 6, the water distributor 7 and the second packer 12 are accommodated in the casing 2; The first perforation tunnel 16 and the second perforation tunnel 17 connected by the first oil layer 20 and the second oil layer 21; the water distributor 7 includes a working cylinder and a flow distribution mechanism installed in the working cylinder, and the working cylinder is provided with the first perforating passage. 16 communicates with the first water outlet 711 of the flow distribution mechanism. The end of the flow distribution mechanism away from the wellhead is formed with a second water outlet 733. The flow distribution mechanism is used to control the working fluid flow of the first water outlet 711 and the second water outlet 733.

The injection pipe string provided in this embodiment is used for water injection or acidizing operations in horizontal wells. Wherein, the oil pipe 1 and the casing pipe 2 are oil pipe and casing structures in the prior art, which are not specifically limited in the present invention. The tubing 1, the first packer 6, the water distributor 7 and the second packer 12 are accommodated in the casing 2, and the casing 2 is provided with a first perforation tunnel 16 and a second perforation tunnel 17 for making the casing The working fluid in 2 flows to different oil layers.

The first packer 6 and the second packer 12 can be packers of any structure such as self-testing packers for water injection, compression packers, and expansion packers in the prior art, The utility model is not specifically limited. The first packer 6 and the second packer 12 are set in a given method, and the packers are attached to the casing wall so that the packers are always in working condition, that is, set. Specifically, the first packer 6 and the second packer 12 are set and in working condition, separating the oil well into a non-production layer 19 near the wellhead, a second oil layer 21 near the bottom of the well, and a non-production layer 19 and the second oil layer. The first oil layer 20 between the two oil layers 21. When the packer needs to be pulled out, the working state of the packer is released according to the given method and load, that is, unpacking. After the layered water injection and acidizing operations are completed, the first packer 6 and the second packer 12 are unpacked and pulled out from the oil well. Of course, after the first packer 6 and the second packer 12 are set, the packers can be checked to verify whether the separation and sealing effects of the packers meet the preset requirements. The first packer 6 and/or the second packer 12 may be a self-testing packer, or a ground playback instrument, an outflow electromagnetic flowmeter and other methods may be selected to test the packer.

In order to test the sealing condition of the packer and ensure that the packer is in a good setting state, as a preferred embodiment, the second packer 12 is a self-testing packer. In actual operation, after throwing the ball in the tubing 1, inject liquid at low pump pressure to send the ball to the ball seat 22, and then continue to pressurize. The rubber cartridge seals the annulus between the tubing and the casing to realize the setting of the first packer 6 and the second packer 12 respectively; continue to increase the pressure, open the seal inspection channel to realize the seal inspection of the second packer 12, and After the seal is qualified, the pressure in the annular space between the tubing and the casing is increased to the set value to realize the seal check of the first packer 6 . After passing the seal inspection, continue to pressurize the oil pipe 1 to the set value, cut off the pin connecting the ball seat 22 and the oil pipe 1, and knock down the ball seat 22, so that the subsequent working fluid can be transported to the second oil layer 21.

The water distributor 7 includes a working barrel and a flow distribution mechanism installed in the working barrel. The working barrel is provided with a first water outlet 711, and the first water outlet 711 communicates with the first perforation channel 16 and the flow distribution mechanism respectively; the flow distribution mechanism A second water outlet 733 is formed at the end away from the wellhead. Part of the working fluid in the tubing 1 passes through the flow distribution mechanism and the first water outlet 711, enters the oil casing annulus 18, and then enters the first oil layer 20 through the first perforation tunnel 16; another part of the working fluid in the tubing 1 passes through the flow distribution mechanism The second water outlet 733 enters the tubing 1 at the lower end, and after reaching one end of the well bottom, enters the second oil layer 21 through the casing annulus 18 and the second perforation tunnel 17 . The flow distribution mechanism is used to control the flow rate of the working fluid in the first water outlet 711 and the second water outlet 733 , thereby controlling the flow rate of the working fluid in the first oil layer 20 and the second oil layer 21 . The flow distribution mechanism may be provided with nozzles to control the flow of the working fluid at the first water outlet 711 and the second water outlet 733, or may be provided with other flow adjustment mechanisms. The water distributor 7 can be provided with joints at both ends of the work cylinder for connecting with the oil pipe 1 .

In this embodiment, the horizontal well uses a separate injection string, and the horizontal well is divided into a non-production layer near the wellhead, a second oil layer near the bottom of the well, and a non-production layer and the second oil layer by the first packer and the second packer. For the first oil layer between the oil layers, the casing is provided with the first perforation channel and the second perforation channel respectively connected with the first oil layer and the second oil layer, and the working cylinder of the water distributor is provided with the first perforation channel and the flow distribution channel. The first water outlet connected with the mechanism, the end of the flow distribution mechanism away from the wellhead forms a second water outlet, the flow distribution mechanism controls the flow of the working fluid from the first water outlet and the second water outlet, and then controls the flow out of the first perforation tunnel and the second water outlet. The working fluid flow rate of the second perforation channel realizes layered water injection and acidification, and the working fluid flow rate of two layers can be measured and adjusted at one time, reducing the operating procedures, shortening the operating cycle, and improving the efficiency of oil extraction.

On the basis of the above embodiments, the flow distribution mechanism includes an upper filter element and a lower filter element; the upper filter element includes an upper channel 78 and a first channel 722 opened on the side of the upper channel 78, and the first channel 722 communicates with the first water outlet 711; The upper channel 78 is provided with a first nozzle 76 for controlling the flow rate of the first channel 722; the lower filter element includes a lower channel 79 and a second channel 732 provided on the side of the lower channel 79, and the second channel 732 is connected to the working cylinder and the upper channel. The annulus 725 between the filter elements is in communication; the lower channel 79 is provided with a second nozzle 77 for controlling the flow of the lower channel 79; the second water outlet 733 is set at the end of the lower channel 79 away from the upper filter element.

Specifically, the flow distribution mechanism in this embodiment includes a first filter element 72 , a second filter element 73 and an intermediate filter element 74 , one end of the intermediate filter element 74 is connected to the first filter element 72 , and the other end is connected to the second filter element 73 . The intermediate filter element 74 can be screwed, clamped, etc. connected with the first filter element 72 and the second filter element 73, and no specific limitation is set here. An upper channel 741 and a lower channel 742 are opened in the middle filter element 74 in the axial direction, and a partition layer 743 is arranged between the upper channel 741 and the lower channel 742 so that the two channels are not connected. Specifically, the upper filter element includes the first filter element 72 and the part above the partition layer 743 of the middle filter element 74 ; the lower filter element includes the second filter element 73 and the part below the partition layer 743 of the middle filter element 74 .

The upper end of the first filter element 72 is provided with a fishing part 724 for engaging with the fishing device to fish the flow distribution mechanism. A third channel 721 is axially opened at the lower end of the fishing part 724 , and the third channel 721 and the upper channel 741 of the middle filter element 74 form an upper channel 78 . A filter hole 723 is opened on the side wall of the third channel 721 , so that the working fluid in the oil pipe 1 enters the third channel 721 through the filter hole 723 . There are a plurality of filter holes 723, arranged in multiple circles and vertically along the side wall of the third channel 721, for example, four filter holes 723 are arranged in the circumferential direction, arranged in 4 rows vertically, the utility model does not make specific details on this limit. The end of the upper channel 741 connected to the first filter element 72 is provided with a first nozzle 76 , and the third channel 721 communicates with the lower channel 741 through the first nozzle 76 . The side wall of the upper channel 741 near the end of the partition layer 743 is opened to form a first channel 722 , and the working cylinder is opened at a corresponding position of the first channel 722 to form a first water outlet 711 , and the first channel 722 communicates with the first water outlet 711 . In addition, there may be multiple first channels 722 arranged at intervals along the circumferential direction of the upper channel 741 . It should be noted that there are also multiple first water outlets 711 corresponding to the first channels 722 one by one.

Referring to Fig. 2 and Fig. 3, in the actual operation process, part of the working fluid in the upper oil pipe 1 enters the third channel 721 through the filter hole 723, and the working fluid in the third channel 721 is controlled by the first nozzle 76 according to the preset flow rate. Enter the upper channel 741 , then enter the oil jacket annulus 18 through the first channel 722 and the first water outlet 711 in sequence, and finally enter the first oil layer 20 through the first perforation tunnel 16 .

The second filter element 73 is connected to the lower end of the intermediate filter element 74, and the lower channel 742 of the intermediate filter element 74 is provided with a second faucet 77 near the end of the partition layer 743, and the lower passage 742 is axially opened through the second faucet 77 and the second filter element 73. The fourth passage 731 communicates with each other, and the lower passage 742 and the fourth passage 731 form the lower passage 79 . The side wall of the lower channel 742 close to the end of the partition layer 743 is opened to form a second channel 732, and the second channel 732 communicates with the annular space 725 between the working cylinder and the upper filter element. A second water outlet 733 is opened on the side wall of the fourth passage 731 away from the second nozzle 77 , so that the working fluid in the fourth passage 731 flows to the lower oil pipe 1 . It should be noted that the second channel 732 may be provided in multiples, such as three, four, etc., and arranged at intervals along the circumferential direction of the lower channel 742 . The second water outlets 733 may also be provided in multiples, such as three, four, etc., arranged at intervals along the circumferential direction of the fourth channel 731 .

Continuing to refer to Fig. 2 and Fig. 3, in the actual operation process, another part of the working fluid in the upper oil pipe 1 enters the annulus 725 between the working cylinder and the upper filter element, bypasses the overflow passage 751, and enters through the second passage 732 The lower channel 742, the second water nozzle 77 controls the working fluid in the lower channel 742 to enter the fourth channel 731 according to the preset flow rate, and then enters the lower oil pipe 1 through the second water outlet 733, and the working fluid flows through the oil pipe 1 to the bottom of the well and enters the oil casing The annular space 18 is finally injected into the second oil layer 21 through the second perforation tunnel 17 .

In this embodiment, the first nozzle 76 and the second nozzle 77 are used to control the flow of the first channel 722 and the fourth channel 731 respectively, thereby controlling the working fluid in the first oil layer 20 and the second oil layer 21 . The first water nozzle 76 and the second water nozzle 77 can be provided with flow holes with different cross-sectional areas to adjust the flow.

As an example of the first faucet and the second faucet, the axis of the first faucet 76 is provided with a first flow hole 761 for connecting the upper passage 78 with the first passage 722 and the axis of the second faucet 77 A second flow hole 771 is opened to communicate with the lower channel 79 and the second water outlet 733 .

Specifically, a first flow hole 761 is opened at the axis of the first faucet 76 so that the third channel 721 of the upper channel 78 communicates with the upper channel 741 . The outer wall of the first faucet 76 is provided with a connecting portion, and the connecting portion can be a snap-fit structure, or a screw thread, etc.; structure, threads, etc., to realize the connection between the first faucet 76 and the upper filter element. As a preferred embodiment, the side wall of the upper channel 741 of the intermediate filter element 74 is provided with a limit step, the side wall of the third channel 721 of the first filter element 72 is also provided with a limit step, and the first nozzle 76 is arranged at two limit steps. Between the position steps, through the connection of the first filter element 72 and the intermediate filter element 74, the fixing of the first faucet 76 by the two limit steps is realized.

The axis of the second faucet 77 is provided with a second flow hole 771 , so that the lower channel 742 of the lower channel 79 communicates with the fourth channel 731 . The outer wall of the second faucet 77 is provided with a connecting portion, and the connecting portion can be a clamping structure, or a screw thread, etc.; etc., realize the connection of the second water nozzle 77 and the lower filter element. As a preferred embodiment, the side wall of the lower channel 742 of the middle filter element 74 is provided with a limit step, the side wall of the fourth channel 731 of the second filter element 73 is also provided with a limit step, and the second nozzle 77 is arranged at two limit steps. Between the position steps, through the connection of the second filter element 73 and the intermediate filter element 74, the fixing of the second faucet 77 by the two limit steps is realized.

When it is necessary to adjust the flow rate of the working fluid in the first oil layer and the second oil layer, the fishing tool is lowered through the steel wire, the flow distribution mechanism is lifted out of the work cylinder, and the water nozzles with different sizes of flow holes are replaced according to the requirements, so as to realize the first oil layer and the second oil layer. Adjustment of working fluid flow in oil layer.

Furthermore, an upper joint 712 is provided at the end of the working cylinder near the wellhead for connecting with the tubing 1 ; a lower joint 752 is provided at the end of the working cylinder near the bottom of the well for connecting with the tubing 1 .

Specifically, the working cylinder includes: an inner cylinder 75 and an outer cylinder 71, and the inner cylinder 75 and the outer cylinder 71 are fixedly connected. The inner cylinder 75 is sleeved on the outside of the first filter element 72, the intermediate filter element 74 and the second filter element 73, and a sealing ring is arranged between the inner cylinder 75 and the first filter element 72, the intermediate filter element 74, and the second filter element 73; the outer cylinder 71 It is sleeved on the outside of the inner cylinder 75 . Wherein, the outer cylinder 71 is opened at the corresponding position of the first channel 722 to form a first water outlet 711, and the side wall of the inner cylinder 75 extends toward the first water outlet 711 to form an overflow channel 751, and the working fluid in the first channel 722 passes through the overflow channel. The channel 751 and the first water outlet 711 enter the oil jacket annulus 18 , and then spray into the first oil layer 20 through the first perforation channel 16 . A passage is defined in the inner cylinder 75 at a position corresponding to the second passage 732 , so that the second passage 732 communicates with the lower passage 742 .

The upper end of the outer cylinder 71 is provided with an upper joint 712 for connecting with the upper oil pipe 1 . The upper joint 712 is preferably a tapered thread, which can be an internal thread or an external thread. The lower end of the inner cylinder 75 is provided with a lower joint 752 for connecting with the lower oil pipe 1 . The lower joint 752 is preferably a tapered thread, which can be an internal thread or an external thread.

On the basis of the above embodiments, the dispensing string for horizontal wells in this embodiment also includes a centralizer set for positioning the second packer 12 in the axial center of the casing 2; the centralizer set includes the first centralizer 11 and the second centralizer 13; the first centralizer 11 is located at one end of the second packer 12 close to the wellhead, and the second centralizer 13 is located at the end of the second packer 12 close to the well bottom.

Affected by the well deviation, the pipe string wears seriously on key parts such as the packer in the process of entering the well, which is likely to cause the failure of the packer. In this embodiment, first centralizers are respectively installed at both ends of the second packer 12 11 and the second centralizer 13, to ensure that the second packer 12 is located in the axial center of the casing 2, and to ensure that the packer will not be worn in the deviated well section and the horizontal section during the well entry process. The first centralizer and the second centralizer may be oil pipe centralizers of any structure in the prior art, and the present invention is not limited thereto.

Further, the dispensing string for horizontal wells in this embodiment also includes a first hydraulic anchor 5 and a second hydraulic anchor 10; the first hydraulic anchor 5 is arranged at one end of the first packer 6 near the wellhead; the second hydraulic anchor 10 It is installed at the end of the first centralizer 11 close to the wellhead.

Specifically, referring to Fig. 1, the first hydraulic anchor 5 is set in the vertical section of the horizontal well and installed on the upper end of the first packer 6. The pressure in the tubing 1 is constantly rising, and the pressure pushes the anchor of the first hydraulic anchor 5. The claws are extended to anchor the string to the casing 2, preventing the first packer 6 from creeping up and down due to pressure fluctuations. The second hydraulic anchor 10 is installed on the upper end of the first centralizer 11 , and has the same function as the first hydraulic anchor 5 and will not be repeated here. The first hydraulic anchor 5 and the second hydraulic anchor 10 can be hydraulic anchors of any structure in the prior art, which is not specifically limited in the present invention. In this embodiment, the fixing of the pipe string is realized by the first hydraulic anchor and the second hydraulic anchor, which prevents the packer from moving up and down due to pressure fluctuations, and avoids uncoordinated first packer and second packer or second packer Second, the tubing was lifted due to the damage of the packer, which ensured the normal progress of the construction work.

In order to prevent the first packer and the second packer from being unsealed abnormally due to the expansion and contraction of the pipe string, the dispensing string for horizontal wells in this embodiment also includes a first telescopic pipe 3 and a second telescopic pipe 8; The pipe 3 is set at the end of the first hydraulic anchor 5 close to the wellhead; the second telescopic tube 8 is set at the end of the water distributor 7 close to the bottom of the well, and the second telescopic tube 8 is located at the side of the first perforation tunnel 16 close to the wellhead.

In water injection and acidizing operations, changes in temperature and water injection pressure may easily cause the expansion and creep of the pipe string. In order to improve the safety of the use of the packer, the injection string for horizontal wells in this embodiment also includes the first telescopic pipe 3 and the second telescopic pipe 3. Two telescopic tubes 8. Wherein, the first telescopic tube 3 is arranged on the upper end of the first hydraulic anchor 5, the second telescopic tube 8 is provided on the lower end of the water distributor 7, and the first telescopic tube 3 and the second telescopic tube 8 are arranged according to different water injection volumes and acidification displacements. length. In addition, in order to prevent sand burial, the first telescopic tube 3 is located in the upper section of the first perforation tunnel 16 .

In order to prevent the downhole tool from being difficult to salvage when the pipe fails, the dispensing string for horizontal wells in this embodiment also includes a first drop joint 4 and a second drop joint 9; the first drop joint 4 is arranged at the first hydraulic Between the anchor 5 and the first telescopic pipe 3; the second hands-off joint 9 is arranged at the end of the second hydraulic anchor 10 close to the wellhead. Specifically, the first hands-free joint 4 and the second hands-free joint 9 may be safety joint structures in the prior art, which are not specifically limited in the present invention. The first hands-off joint 4 is installed between the first hydraulic anchor 5 and the first telescopic pipe 3. When the pipe fails, the first hands-off joint 4 is opened, and the pipe string below is salvaged by fishing tools such as drill pipes; The second drop-off joint 9 is arranged on the upper end of the second hydraulic anchor 10. When the pipe removal fails, the second drop-off joint 9 is opened, and the following pipe string is salvaged by fishing tools such as drill pipes.

Furthermore, the injection string for horizontal wells in this embodiment also includes a sand control screen 14 and a shoe plug 15; the shoe plug 15 is arranged at the end of the tubing near the bottom of the well; Plug 15 away from the end of the bottom of the well. Specifically, the boot shoe plug 15 is arranged at the end of the tubing 1 close to the bottom of the well for guiding the tubing 1 . A screen 14 is arranged on the upper end of the shoe plug 15. During water injection or acidizing operations, the working fluid in the tubing 1 enters the oil jacket annulus 18 through the screen 14, and enters the second oil layer 21 from the second perforation tunnel 17. The shoe plug and the screen can be existing plug and screen structures, which are not specifically limited in the present invention.

In the description of the present utility model, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the above description, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean specific features, structures described in connection with the embodiment or example , material or feature is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present utility model, and are not intended to limit it; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand : It can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the embodiments of the present utility model Scope of technical solutions.

Claims (10)

1. a kind of injection pipe string for horizontal well, it is characterized in that, comprises: oil pipe, sleeve pipe, the first packer, water distribution device and the second packer; Described oil pipe is installed successively from wellhead to bottom hole The first packer, the water distributor and the second packer, and the first packer and the water distributor are located in the vertical section of the horizontal well, and the second packer is located in the horizontal well the horizontal section; The first packer and the second packer separate the horizontal well into a non-production layer near the wellhead, a second oil layer near the bottom of the well, and a second oil layer located between the non-production layer and the the first oil layer between the second oil layers; The oil pipe, the first packer, the water distributor and the second packer are accommodated in the casing; The first perforation tunnel and the second perforation tunnel connected by the oil layer; The water distributor includes a working cylinder and a flow distribution mechanism placed in the working cylinder. The working cylinder is provided with a first water outlet communicating with the first perforation channel and the flow distribution mechanism. The flow distribution A second water outlet is formed at the end of the mechanism away from the wellhead, and the flow distribution mechanism is used to control the flow of working fluid at the first water outlet and the second water outlet. 2. The dispensing string for horizontal wells according to claim 1, wherein the flow distribution mechanism comprises an upper filter element and a lower filter element; The upper filter element includes an upper channel and a first channel opened on the side of the upper channel, and the first channel communicates with the first water outlet; the upper channel is provided with a first faucet for controlling the flow rate of the first channel; The lower filter element includes a lower channel and a second channel opened on the side of the lower channel, and the second channel communicates with the annulus between the working cylinder and the upper filter element; the lower channel is provided with The second water nozzle is used to control the flow of the lower channel; the second water outlet is set at the end of the lower channel away from the upper filter element. 3. The dispensing pipe string for horizontal wells according to claim 2, wherein a first flow hole is provided at the axis of the first nozzle for communicating with the upper channel and the first channel ; A second flow hole is opened at the axis of the second nozzle for communicating with the lower channel and the second water outlet. 4. The dispensing string for horizontal well according to claim 2, characterized in that, an upper joint is arranged at the end of the working cylinder close to the wellhead for connecting with the tubing; the working cylinder is close to the One end of the well bottom is provided with a lower joint for connecting with the tubing. 5. The dispensing string for horizontal wells according to any one of claims 1-4, further comprising a set of centralizers for positioning the second packer in the axial direction of the casing. center; The centralizer group includes a first centralizer and a second centralizer; the first centralizer is located at one end of the second packer close to the wellhead, and the second centralizer is located at the end of the second packer One end of the spacer near the bottom of the well. 6. The split injection string for horizontal wells according to claim 5, wherein the second packer is a self-testing packer. 7. The dispensing string for horizontal wells according to claim 5, further comprising a first hydraulic anchor and a second hydraulic anchor; the first hydraulic anchor is arranged near the first packer One end of the wellhead; the second hydraulic anchor is arranged at one end of the first centralizer close to the wellhead. 8. The dispensing string for horizontal wells according to claim 7, further comprising a first telescopic tube and a second telescopic tube; the first telescopic tube is arranged near the first hydraulic anchor One end of the wellhead; the second telescopic tube is provided at the end of the water distributor close to the bottom of the well, and the second telescopic tube is located at the side of the first perforation tunnel close to the wellhead. 9. The dispensing string for horizontal wells according to claim 8, further comprising a first hand-off joint and a second hand-off joint; the first hand-off joint is arranged on the first hydraulic anchor and the first telescopic pipe; the second release joint is arranged at the end of the second hydraulic anchor close to the wellhead. 10. The split injection string for horizontal wells according to any one of claims 1-4, characterized in that it also includes a sand control screen and a shoe plug; One end of the bottom of the well; the sand control screen is arranged at the end of the shoe plug away from the bottom of the well.