CN110685611B

CN110685611B - Pipe column and method for abrasive perforation and soluble bridge plug combined double-cluster fracturing

Info

Publication number: CN110685611B
Application number: CN201810730061.1A
Authority: CN
Inventors: 耿黎东; 王敏生; 蒋海军; 思娜; 光新军
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2018-07-05
Filing date: 2018-07-05
Publication date: 2021-06-15
Anticipated expiration: 2038-07-05
Also published as: CN110685611A

Abstract

The invention provides a pipe column for abrasive perforation and soluble bridge plug combined double-cluster fracturing, which comprises: the spray gun comprises a first spray gun and a second spray gun which are hollow, wherein the side walls of the first spray gun and the second spray gun are respectively provided with a first spray nozzle and a second spray nozzle, the interiors of the first spray gun and the second spray gun are respectively provided with a first sliding sleeve and a second sliding sleeve, and the first sliding sleeve and the second sliding sleeve are respectively fixed through a first pin and a second pin to close the first spray nozzle and the second spray nozzle in an initial state; the setting tool and the soluble bridge plug are sequentially connected to the downstream end of the second spray gun; the first and second sliding sleeves can open the first and second nozzles under the action of set pressure to perform perforation and fracturing construction. And resistance reducing layers for reducing the resistance of the first sliding sleeve and the second sliding sleeve are arranged on the inner walls of the first spray gun and the second spray gun. And the outer walls of the first spray gun and the second spray gun and the surfaces of the first spray nozzle and the second spray nozzle are provided with anti-corrosion and anti-abrasion enhancement layers. The invention also provides a method for dual-cluster fracturing by combining abrasive perforation and soluble bridge plugs.

Description

Pipe column and method for abrasive perforation and soluble bridge plug combined double-cluster fracturing

Technical Field

The invention relates to the technical field of oil and natural gas exploitation, in particular to a tubular column for dual-cluster fracturing by combining abrasive perforation and a soluble bridge plug. The invention also provides a method for dual-cluster fracturing by combining abrasive perforation and soluble bridge plugs.

Background

With the rapid development of economy in China, the demand for oil and gas resources is increasing. However, the probability of finding conventional reservoirs is becoming smaller and smaller, and the development of unconventional low permeability reservoirs with abundant reserves is receiving more and more attention. Taking natural gas as an example, the geological reserve of newly added conventional gas in 2016 of China is 6540 billionths of cubic meters, and the low-permeability gas and the dense gas account for 73 percent. Low permeability reservoirs have become an important unconventional energy source, and hydraulic fracturing is an effective way to mobilize and enhance low permeability reserves. In order to improve the yield of unconventional oil and gas resources such as low permeability gas, shale gas and the like, the horizontal well staged volume fracturing gradually becomes a main development mode. A method of fracturing multiple clusters in sections and multiple clusters simultaneously is adopted, and a staggered complex seam network is formed by utilizing mutual interference among the fractures, so that the reconstruction volume can be increased.

At present, the commonly used staged fracturing methods mainly include: flow-limiting staged fracturing, hydraulic jet staged fracturing, immobile string packer staged fracturing, drillable bridge plug staged fracturing, soluble bridge plug staged fracturing and the like. The staged fracturing by the flow limiting method has relatively poor pertinence, and the required perforation density is low, so that the effective wellbore radius expansion of the perforation is prevented. Also, during operation, excessive pressure drops may occur at the perforation tunnels and at the fracture inlets, and may affect the distribution of sand-laden fracturing fluid between the formations. In addition, the flow-restricting method provides a smaller fracture entrance area for perforating, which tends to allow proppant to return during flowback and production.

The hydraulic jet staged fracturing is a novel yield-increasing transformation technology integrating hydraulic jet perforation, hydraulic fracturing and isolation. Although accurate fixed-point injection can be realized, the actual hydraulic packing effect of the technology is poor, and in the abrasive material perforating, injecting and layering fracturing construction process, fracturing fluid easily flows to constructed closed cracks, so that the cracks are opened again, the sand spitting phenomenon is caused, and the staged fracturing effect is seriously influenced. Meanwhile, the technology can only fracture one section of reservoir stratum by one-time ball throwing, and is not beneficial to forming a complex fracture network. In addition, the abrasive perforation and back splash seriously abrade the surface of the tool, and the abrasive can also cause the diameter of the nozzle to be expanded, thereby influencing the jetting effect.

The principle of the staged fracturing process of the immobile pipe string packer is that after each fracturing layer section is jetted once, a pipe string with a plurality of packers is put in, and the existing perforating sections are separated by using the packers. And the balls with smaller and smaller sizes are put into the fracturing device in sequence to open the sliding sleeves with different stages, so that fracturing is carried out on different intervals. However, in the implementation process of the process, as the pipe column creeps, the packer is easy to set in advance, and the reservoir cannot be effectively sealed.

The drillable composite bridge plug staged fracturing construction period is relatively long, the cost is high, and the problems that the bridge plug is difficult to pump, the bridge plug is not released during setting and the like exist.

The soluble bridge plug staged fracturing string realizes staged fracturing by implementing in-stage sand blasting perforation induced staged fracturing and continuous oil pipe plug feeding. However, when the pipe column is used for sand blasting, perforating and staged fracturing, sand grains have serious back-splash impact on the outer wall of the ejector, and the abrasion of the ejector is easily caused. In addition, the nozzle is expanded due to the abrasion of sand grains, and the jet fracturing effect is seriously influenced.

Disclosure of Invention

In response to at least some of the technical problems described above, the present invention is directed to a string for abrasive perforation dual cluster fracturing in conjunction with a soluble bridge plug. The pipe column is subjected to simultaneous fracturing of two clusters, so that a complex seam net is formed, and the volume fracturing effect is improved. And the outer wall surface of the spray gun of the pipe column, the outer surface of the short section and the surface of the nozzle are provided with the enhanced layer films formed by the graphene/boron nitride nano multilayer films, so that the problem of abrasion of the abrasive to the surface of the tool and the nozzle in the abrasive perforating and jetting fracturing process is solved. And the inner wall surface of the spray gun and the inner surface of the short section are provided with a resistance reduction layer film formed by a graphene/titanium nitride nano multilayer film, so that the resistance reduction effect is achieved, and the sliding sleeve can slide in the spray gun. The hydraulic packing effect of abrasive material perforation jet fracturing is improved, and the phenomenon of sand spitting is avoided when the fracture is pressed. In addition, the application of the soluble bridge plug greatly shortens the construction period and obviously improves the construction efficiency.

The invention also provides a method for abrasive perforation and soluble bridge plug combined double-cluster fracturing, which uses the pipe string for abrasive perforation and soluble bridge plug combined double-cluster fracturing to perform operation.

To this end, according to the present invention, there is provided a string for dual cluster fracturing of abrasive perforations in conjunction with a soluble bridge plug, comprising: the spray gun comprises a first spray gun and a second spray gun which are constructed into hollow cylinders, wherein a plurality of first nozzles and a plurality of second nozzles are respectively arranged on the side walls of the first spray gun and the second spray gun, and the first spray gun and the second spray gun are distributed at intervals and connected through short sections; a first and second sliding sleeves disposed within the first and second spray guns, respectively, the first and second sliding sleeves configured to be secured by first and second pins, respectively, to close the first and second spray nozzles in an initial state; the setting tool and the soluble bridge plug are sequentially connected to the downstream end of the second spray gun; the first sliding sleeve and the second sliding sleeve can shear the first pin and the second pin under the action of set pressure and slide to the downstream of the second nozzle, so that the first nozzle and the second nozzle are opened for perforation and fracturing construction.

In a preferred embodiment, the first runner has an inner diameter greater than an inner diameter of the second runner.

In a preferred embodiment, a limiting step for preventing the second sliding sleeve from sliding out of the second spray gun is arranged at the inner wall of the lower end of the second spray gun, and the limiting step is arranged to extend radially inwards.

In a preferred embodiment, the pipe column further comprises a pressure-building ball for building pressure on the first and second sliding sleeves to cut off the first and second pins to open the first and second nozzles, and the diameter of the pressure-building ball is larger than the inner diameter of the first sliding sleeve and smaller than the inner diameters of the first and second spray guns.

In a preferred embodiment, the total length of the first sliding sleeve and the second sliding sleeve and the diameter of the pressure-holding ball is smaller than the distance from a second nozzle in the second spray gun to the limiting step.

In a preferred embodiment, a safety joint for connecting an oil pipe is arranged at the upstream end of the first spray gun, and a centralizer and a positioning instrument are further connected between the first spray gun and the safety joint.

In a preferred embodiment, the setting tool and the dissolvable bridge plug are connected by a drop bolt.

In a preferred embodiment, the inner walls of the first spray gun, the second spray gun and the short section are all provided with a drag reduction layer film, the drag reduction layer film is made of graphene/titanium nitride nano materials, and the thickness of the drag reduction layer film is less than 10 μm.

In a preferred embodiment, the outer walls of the first spray gun and the second spray gun and the surfaces of the first nozzle and the second nozzle are respectively provided with an enhancement layer film, and the enhancement layer film is made of graphene/boron nitride nano materials and has a thickness of less than 10 μm.

A method for abrasive perforation in combination with soluble bridge plugs for dual cluster fracturing, wherein the method uses a tubular string as described above, comprising the steps of:

the method comprises the following steps: the pipe column is lowered to a preset position in a shaft through an oil pipe, and positioning is carried out through a positioning instrument;

step two: putting a setting ball into a wellhead, pressing the ground, setting the soluble bridge plug through the setting tool, after releasing is finished, putting the pressure-holding ball into the wellhead, and continuously pressing the ground to enable the pressure-holding ball to sequentially shear the first pin and the second pin and slide to the position below the second nozzle, so that the first nozzle and the second nozzle are opened, wherein the diameter of the setting ball is smaller than the inner diameter of the second sliding sleeve;

step three: pumping perforating fluid into the tubular column from the ground, performing perforating operation through the first nozzle and the second nozzle, pumping fracturing fluid into the tubular column, performing fracturing operation, and taking out the tubular column after the fracturing operation is completed;

step four: repeating the steps, and performing the next section of perforating and fracturing operation until the perforating and fracturing operations of all the sections are completed;

step five: and (4) performing open flow, and after the soluble bridge plug is dissolved automatically, putting the soluble bridge plug into a production pipe column for production.

Drawings

The invention will now be described with reference to the accompanying drawings.

FIG. 1 shows the structure of a tubular string for staged fracturing with abrasive perforations in conjunction with a bridge plug in accordance with the present invention.

Fig. 2 shows a schematic diagram of the graphene/titanium nitride nano-multilayer film grown on the metal wall surface.

Fig. 3-9 show schematic construction steps of a method of staged fracturing using a tubular string for abrasive perforation in conjunction with a bridge plug according to the present invention.

In the present application, the drawings are all schematic and are used only for illustrating the principles of the invention and are not drawn to scale.

Detailed Description

The invention will be described in further detail with reference to the drawings and specific examples, without thereby limiting the scope of the invention.

It is noted that in this application, when a string for abrasive perforation and soluble bridge plug combined in a dual cluster fracturing is lowered into a downhole operation, the end near the wellhead is defined as the "upstream end" or the like, while the end away from the wellhead is defined as the "downstream end" or the like.

FIG. 1 shows the configuration of a tubular string 100 for abrasive perforation in combination with soluble bridge plugs for dual cluster fracturing in accordance with the present invention. As shown in fig. 1, the pipe string 100 comprises a safety joint 2, a centralizer 3, a positioning tool 4, a first spray gun 5, a pup joint 10, a second spray gun 11, a hydraulic setting device 17 and a soluble bridge plug 18 which are connected in sequence from top to bottom, and the tools are connected in sequence to form a perforation fracturing tool string. The pipe string 100 is connected with a conventional oil pipe or a coiled tubing 1 through a safety joint 2.

In one embodiment, the plain or coiled tubing 1, the positioning tool 4, the first lance 5, the second lance 11, the sub 10 and the hydraulic setting tool 17 are all threaded together. Meanwhile, the soluble bridge plug 18 and the hydraulic setting device 17 are connected together by a releasing bolt.

In use, the pipe string 100 is tested at the surface by the tools in the pipe string 100, and the tools are connected in the design sequence shown in fig. 1 after passing the test. One end (left end in fig. 1) of the pipe string 100 is connected to a conventional oil pipe or a coiled oil pipe 1 through a safety joint 2. During operation, the string 100 is lowered from the wellhead to a predetermined position in the bottom of the well by pulling the coiled tubing 1.

As shown in fig. 1, the positioning tool 4 is disposed at an upper portion of the tubular string 100, and is used for positioning the tubular string 100 when the tubular string 100 is lowered into the wellbore, so that the tubular string 100 can be accurately lowered into a predetermined position in the wellbore, the efficiency of the perforating fracturing operation is improved, and the effect of the perforating fracturing operation is enhanced. In addition, the centralizer 3 is arranged between the safety joint 2 and the positioning instrument 4 and used for centralizing the tubular column 100 in the construction process, so that the stability of the tubular column 100 and the accuracy of perforation are guaranteed, and the construction effect of perforation fracturing of the tubular column 100 is further enhanced.

As shown in fig. 1, the column 100 includes a first spray gun 5 and a second spray gun 11 as column bodies. The first spray gun 5 and the second spray gun 11 are each configured in a hollow cylindrical structure. The first lance 5 and the second lance 11 are spaced apart and connected by a nipple 10, the first lance 5 being at the upstream end of the second lance 11. The side walls of the first spray gun 5 and the second spray gun 11 are respectively provided with a plurality of first nozzles 6 and a plurality of second nozzles 12, wherein the number of the first nozzles 6 or the number of the second nozzles 12 are at least 2. The specific number of the first nozzles 6 and the second nozzles 12 is determined according to the fracturing discharge capacity and the sand adding amount in actual construction, and the plurality of the first nozzles 6 and the plurality of the second nozzles 12 are arranged along different radial directions. The first nozzles 6 and the second nozzles 12 are used for jetting perforating fluid at high pressure to perform perforating operation, double-cluster fracturing is performed through the first nozzles 6 and the second nozzles 12, stress interference is generated in the process that the first spray gun 5 and the second spray gun 11 form cracks, a complex crack net is favorably formed, and the volume fracturing effect can be remarkably improved.

In one embodiment, the sub 10 is a seamless steel pipe, and the length of the sub 10 is determined by the distance between adjacent fractures where perforation fracturing is desired.

According to the invention, a first sliding sleeve 9 is provided in the first lance 5. As shown in fig. 1, the first sliding sleeve 9 is configured to be fixed by the first pin 7 to close the first nozzle 6 in an initial state. Meanwhile, a second slide 14 is provided in the second spray gun 11, and the second slide 14 is configured to be fixed by the second pin 13 to close the second nozzle 12 in an initial state. The first sliding sleeve 9 can shear the first pin 7 under the action of external force and slide to the lower part of the first nozzle 6, so that the first nozzle 6 is opened. The inner wall of the first spray gun 5 is smooth, and the first sliding sleeve 9 can slide out of the first spray gun 5 and enter the second spray gun 11 through the short section 10. The second sliding sleeve 14 can shear the second pin 13 under the action of external force and slide to the downstream of the second nozzle 12, thereby opening the second nozzle 12. Increasing the applied force in turn shears the first pin 7 and the second pin 13 and opens the first nozzle 6 and the second nozzle 12. The lower extreme of second spray gun 11 is provided with spacing step 15, and spacing step 15 is radially inwards protruding for prevent that second sliding sleeve 14 roll-off second spray gun 11.

According to the invention, the inner diameter of the first sliding sleeve 9 in the first spray gun 5 is greater than the inner diameter of the second sliding sleeve 14 in the second spray gun 11. The string 100 also includes a pressure build ball 8 capable of pressure building the first sliding sleeve 9 to shear the first pin 7 and move down. In one embodiment, the pressure-holding ball 8 is a steel ball. The diameter of the pressure building ball 8 is larger than the inner diameter of the first sliding sleeve 9 and smaller than the inner diameters of the first spray gun 5 and the second spray gun 11. The sum of the length of the first sliding sleeve 9 in the first spray gun 5, the length of the second sliding sleeve 14 in the second spray gun 11 and the diameter of the pressure build-up ball 8 is less than the distance from the second nozzle 12 of the second spray gun 11 to the limit step 15, so that the second nozzle 12 can be opened.

As shown in fig. 1, a hydraulic setting tool 17 is connected to the lower end of the second lance 11, and a soluble bridge plug 18 is connected to the lower end of the hydraulic setting tool 17 by a throwout bolt. Before construction, when the soluble bridge plug 18 in the pipe column 100 is lowered to a preset position in a shaft, the setting ball 16 is thrown into a wellhead, the ground is pressed, and the soluble bridge plug 18 is set by high-pressure liquid, so that releasing is completed. In this embodiment, the diameter of the setting ball 16 is smaller than the inner diameter of the second sliding sleeve 14, and can pass through the limit step 15 at the lower end of the second spray gun 11. Preferably, the setting ball 16 is a steel ball. The mode of adopting the ball-throwing hydraulic setting bridge plug avoids using gunpowder, obviously reduces the construction difficulty and improves the safety. In one embodiment, the rubber cartridge of the dissolvable bridge plug 18 is a PPA sealing rubber cartridge, and the slips, mandrel, cone, joint, etc. are all made of a dissolvable magnesium aluminum alloy.

According to the invention, resistance reducing layers are arranged on the inner walls of the first spray gun 5, the second spray gun 11 and the short joint 10. In one embodiment, the drag reduction layer is a multilayer film formed by graphene/titanium nitride nano materials. The friction coefficient of the graphene is only 0.2, the titanium nitride also has excellent resistance reducing performance, and the graphene and the titanium nitride are alternately deposited and grown on the inner surfaces of the first spray gun 5, the second spray gun 11 and the short section 10. According to the invention, the graphene/titanium nitride nano multilayer film is alternately stacked by more than 100 layers, and the thickness of the graphene/titanium nitride nano multilayer film is less than 10 mu m. The drag reduction effect of the inner surfaces of the first spray gun 5, the second spray gun 11 and the short section 10 is greatly improved through the multilayer film, and the sliding of the first sliding sleeve 9 in the first spray gun 5, the second spray gun 11 and the short section 10 is facilitated. Meanwhile, by using a layer-by-layer self-assembly method, the outer walls of the first spray gun 5, the second spray gun 11 and the short joint 10 and the surfaces of the first nozzle 6 and the second nozzle 12 are provided with reinforced layers. In one embodiment, the enhancement layer employs a multilayer film formed of graphene/boron nitride nanomaterials. According to the invention, the graphene/titanium nitride nano multilayer film is alternately stacked by more than 100 layers, and the thickness of the graphene/titanium nitride nano multilayer film is less than 10 mu m. As shown in fig. 2, a resistance reducing layer or an enhancing layer is disposed on the metal wall 30 of the inner wall or the outer wall of the first spray gun 5, the second spray gun 11 and the short joint 10, wherein the resistance reducing layer or the enhancing layer is a multilayer film formed by a plurality of layers of graphene materials 31 and titanium nitride or boron nitride nano materials 32. The graphene and the boron nitride both have the characteristics of high abrasion resistance, high hardness, strong chemical stability and the like, so that the abrasion resistance and the corrosion resistance of the outer walls of the first spray gun 5, the second spray gun 11 and the short section 10 and the surfaces of the first nozzle 6 and the second nozzle 12 are greatly improved, and the common problems of serious abrasion of the spray gun by the abrasive, diameter expansion of the nozzle and the like in the conventional abrasive perforation and fracturing are effectively solved.

According to the tubular column 100 for the abrasive perforation and soluble bridge plug combined double-cluster fracturing, double-cluster simultaneous fracturing is formed through the first spray gun 5 and the second spray gun 11, so that a complex fracture network is formed, and the volume fracturing effect is effectively improved. And the graphene/boron nitride nano multilayer film is arranged on the outer wall surface of the spray gun of the pipe column 100, the outer surface of the short section and the surface of the nozzle, so that the problem of abrasion of the abrasive to the surface of a tool and the nozzle in the abrasive perforating jet fracturing process is effectively solved. And the graphene/titanium nitride nano multilayer film is arranged on the inner wall surface of the spray gun and the inner surface of the short section, so that the drag reduction effect is achieved, and the sliding sleeve can slide in the spray gun. Meanwhile, the tubular column 100 effectively improves the hydraulic packing effect of abrasive material perforation jet fracturing, and ensures that the fractured cracks can not generate sand spitting. In addition, the application of the soluble bridge plug greatly shortens the construction period and obviously improves the construction efficiency.

The present invention also provides a method for abrasive perforation and soluble bridge plug combined double cluster fracturing using the pipe string 100 according to the present invention, the working process of which is briefly described below.

First, each tool in the string 100 is tested at the surface, and after passing the test, the tool string is assembled by connecting according to the design sequence shown in fig. 1. Then, a perforation fracturing operation is performed by the following steps.

The method comprises the following steps: the pipe string 100 is lowered from the wellhead to a predetermined position in the well bottom through the plain or coiled tubing 1 and positioned by the locator 4.

Step two: and carrying out the first-stage double-cluster perforation and fracturing operation. After lowering the soluble bridge plug 18 to the design position, the setting ball 16 is dropped into the wellhead and the surface is pressurized, thereby setting the soluble bridge plug 18 with high pressure liquid, completing the release, as shown in fig. 3. Then, as shown in fig. 4, a pressure-holding ball 8 is thrown into the wellhead, the liquid pushes the pressure-holding ball 8 into the first spray gun 5, and the first spray gun sits on the first sliding sleeve 9, and the ground is pressurized, so that the pressure-holding ball 8 pushes the first sliding sleeve 9 to cut off the first pin 7. Then, as shown in fig. 5, the first sliding sleeve 9 slides out of the first spray gun 5, enters the second spray gun 11 through the short section 10, contacts with the second sliding sleeve 14 in the second spray gun 11, the ground is pressurized again, the first sliding sleeve 9 pushes the second sliding sleeve 14 to cut off the second pin 13 in the second spray gun 11, and the pressure-building ball 8, the first sliding sleeve 9 and the second sliding sleeve 14 slide down the limit step 15 to stop sliding. Thereby opening the first nozzle 6 and the second nozzle 12.

Step three: high pressure perforating fluid is pumped into the tubing string 100 from the surface and, as shown in fig. 6, is injected at high velocity through the first and

second nozzles

6 and 12 on the first and

second guns

5 and 11, respectively, toward the sidewall of the casing 110 and the formation 120 to perform a perforating operation, thereby creating perforations in the formation. The arrows in the axial direction of the tubular string 100 in fig. 6 indicate the flow direction of the perforating fluid in the tubular string 100, while the arrows in the radial direction of the tubular string 100 indicate the perforating direction of the high-pressure injection of the perforating fluid. After the perforation is finished, as shown in fig. 7, pumping fracturing fluid from a common oil pipe or a continuous oil pipe 1 and the shaft annulus according to the discharge capacity required by the design, performing fracturing operation, and after the abrasive perforation double-cluster fracturing operation is completed, taking out the pipe string 100. The arrows in the axial direction of the tubing string 100 in fig. 7 indicate the direction of flow of the fracturing fluid in the common tubing or coiled tubing 1 and the wellbore annulus, while the arrows in the radial direction of the tubing string 100 indicate the direction of high pressure injection of the fracturing fluid.

Step four: and repeating the steps, and performing the next stage of perforating and fracturing operation until all stages of perforating and fracturing operation are completed as shown in figure 8.

Step five: after completion of the perforation fracturing operation of all sections downhole, as shown in fig. 9, the soluble bridge plugs 18 dissolve to disappear automatically to facilitate the production of oil and gas in the formation, and are lowered into the production string for blowout production.

The arrows in the radial direction of the wellbore in fig. 8 and 9 indicate the injection direction of the perforating fluid and fracturing fluid in the perforating fracturing operation of the tubular string 100.

According to the invention, in order to enhance the perforating effect, an abrasive is added into the perforating fluid. Preferably, the abrasive is 5-10% by volume of the perforating fluid. In one embodiment, the abrasive may be quartz sand, and the particle size of the abrasive is preferably 20 to 40 mesh. Also, in one embodiment, the fracturing fluid is 30% proppant by volume of the fracturing fluid. Preferably, the proppant adopts ceramsite with the particle size of 20-40 meshes.

According to the staged fracturing method using the tubular column 100, the perforation efficiency is improved through simultaneous fracturing of double clusters, and the complex fracture network is favorably formed through the mutual influence of the stress generated among the multiple clusters of perforations, so that the volume fracturing effect is effectively improved. The pipe column 100 improves the hydraulic packing effect of abrasive perforating jet fracturing, and can effectively ensure that the pressed crack does not generate sand spitting in the construction process of abrasive perforating jet layered fracturing. And by using the soluble bridge plug 18, the working time is greatly saved, and the construction efficiency of perforation fracturing operation is further improved. In addition, the staged fracturing performed by the pipe string 100 can effectively avoid casing deformation caused by perforation and fracturing processes. Meanwhile, the method solves the problem of poor packing effect of conventional hydraulic jet fracturing, and has the advantages of wide application range, simple construction process, strong reliability and the like.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tubular string (100) for abrasive perforating in conjunction with soluble bridge plugs for dual cluster fracturing, comprising:

the spray gun comprises a first spray gun (5) and a second spray gun (11) which are constructed into hollow cylinders, wherein a plurality of first nozzles (6) and a plurality of second nozzles (12) are respectively arranged on the side walls of the first spray gun and the second spray gun, and the first spray gun and the second spray gun are distributed at intervals and are connected through short joints (10);

a first sliding sleeve (9) and a second sliding sleeve (14) respectively arranged inside the first spray gun and the second spray gun, the first sliding sleeve and the second sliding sleeve are respectively fixed by a first pin (7) and a second pin (13) to close the first spray nozzle and the second spray nozzle in an initial state;

a setting tool (17) and a soluble bridge plug (18) connected in sequence to the downstream end of the second lance;

wherein the first sliding sleeve and the second sliding sleeve can shear the first pin and the second pin under the action of set pressure and slide to the downstream of the second nozzle so as to open the first nozzle and the second nozzle for perforation and fracturing construction,

the spray gun comprises a first spray gun body, a second spray gun body, a nipple joint, a first spray gun body, a second spray gun body, a first spray gun body and a second spray gun body, wherein the first spray gun body, the second spray gun body and the nipple joint are arranged on the first spray gun body, the second spray gun body and the nipple joint, the first spray gun body, the second spray gun body and the first spray gun body are arranged on the first spray gun body, the second spray gun body and the.

2. The tubular string of claim 1, wherein an inner diameter of the first sleeve is greater than an inner diameter of the second sleeve.

3. The pipe string according to claim 1 or 2, wherein a limiting step (15) for preventing the second sliding sleeve from sliding out of the second spray gun is arranged on the inner wall of the second spray gun, and the limiting step is arranged to extend radially inwards.

4. The pipe string according to claim 3, further comprising a pressure build-up ball (8) for building up pressure on the first and second sliding sleeves to shear the first and second pins to open the first and second nozzles, wherein the pressure build-up ball has a diameter larger than an inner diameter of the first sliding sleeve and smaller than inner diameters of the first and second spray guns.

5. The pipe string of claim 4, wherein the total length of the first sliding sleeve and the second sliding sleeve and the diameter of the pressure build-up ball is smaller than the distance from a second nozzle in the second spray gun to the limiting step.

6. A pipe string according to claim 1, characterized in that a safety joint (2) for connecting a tubing is provided at the upstream end of the first lance, and a centralizer (3) and a locator (4) are connected between the first lance and the safety joint.

7. A pipe string according to claim 1, characterized in that the setting tool (17) and the soluble bridge plug (18) are connected by a throwout bolt.

8. The pipe string of claim 1 or 2, wherein the drag reducing layer film has a thickness of less than 10 μm.

9. A pipe string according to claim 1 or 2, wherein the reinforcement layer membrane has a thickness of less than 10 μm.

10. A method for abrasive perforation in dual cluster fracturing in conjunction with soluble bridge plugs, using a tubular string according to any of claims 1 to 9, comprising the steps of:

step two: a well mouth is thrown into a setting ball (16), ground is pressurized, the soluble bridge plug is set by the setting tool, after releasing is completed, the well mouth is thrown into a pressure-holding ball, and ground is continuously pressurized, so that the pressure-holding ball sequentially cuts off the first pin and the second pin and slides to the position below the second nozzle, the first nozzle and the second nozzle are opened, and the diameter of the setting ball is smaller than the inner diameter of the second sliding sleeve;