CN117780321A - Multilayer immobile string combining small-displacement perforation and large-displacement fracturing and construction method thereof - Google Patents

Abstract

The invention provides a multi-layer immobile string combined by small-displacement perforation and large-displacement fracturing and a construction method thereof, wherein the immobile string comprises an oil pipe, a safety joint, a multi-layer immobile string combination unit, a first-layer immobile string combination unit and a single-flow valve which are sequentially arranged from top to bottom, and the first-layer immobile string combination unit comprises a first-stage sliding sleeve packer, a first-stage adjusting oil pipe, a sliding sleeve type hydraulic injector and a large-diameter packer which are sequentially arranged from top to bottom; the multi-layer immobile pipe column combined unit comprises a second layer immobile pipe column combined unit and an nth layer immobile pipe column combined unit which are sequentially arranged from bottom to top, wherein a plurality of combined units are continuously arranged in the second layer immobile pipe column combined unit; the nth layer of fixed tubular column combination unit comprises an nth level sliding sleeve packer, an nth level adjusting oil pipe and an nth level hydraulic jetting sand packing integrated tool which are sequentially arranged from top to bottom. The fixed tubular column solves the construction problem of combination of one-trip drilling multi-layer small-displacement perforation and large-displacement fracturing, and realizes bidirectional packing of stratum at perforation positions.

Description

Multilayer immobile string combining small-displacement perforation and large-displacement fracturing and construction method thereof

Technical Field

The invention relates to the technical field of reservoir transformation of oil and gas fields, in particular to a multi-layer stationary pipe column combining small-displacement perforation and large-displacement fracturing and a construction method of the multi-layer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing.

Background

At present, the construction mode of fire perforation-scraping-fracturing is mainly adopted in the construction of the fixed tubular column, three rounds of drilling are needed to be started and stopped for one-time construction, the time consumption is long, the safety risk of drilling is high in the night after perforation, meanwhile, the construction limit is high, and the normal production organization on site can be influenced due to the requirements of safety forbidden stop and the like, so that the construction efficiency is reduced. Although the hydraulic sand blasting perforation fracturing technology has the characteristics of deep penetration, small stratum damage and low construction risk, in the operation, the hydraulic flow circulation is required to be established, only single-layer construction can be completed at a time, construction can be continued after stratum pressure is released through the steps of open blasting and the like, and the construction displacement in the fracturing process is smaller and cannot be further improved due to the fact that sand is added through a perforation tool. Therefore, the multilayer immobile string combining the small-displacement perforation and the large-displacement fracturing and the construction method thereof have important significance.

The application number is CN201310552299.7, and the Chinese patent with the name of hydraulic injection double-seal single-clamp perforation and fracturing integrated process pipe column discloses a hydraulic injection double-seal single-clamp perforation and fracturing integrated process pipe column, which realizes fracturing of multiple layers of a vertical well or multiple sections of a horizontal well by dragging the pipe column in a single pass, is not a fixed pipe column construction, and simultaneously fails to effectively solve the problem of large-displacement fracturing construction.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the purposes of the invention is to provide a small-displacement perforation and large-displacement fracturing combined multilayer stationary tubular column which has a reasonable structure and is suitable for multilayer or horizontal wells of a vertical well of an oil and gas field and can realize one-time drilling to complete multilayer hydraulic jet fracturing construction. For another example, another object of the invention is to provide a construction method for realizing accurate perforation fracturing of a construction layer section, completing the combination of one-time drilling multi-layer small-displacement perforation and large-displacement fracturing, improving the construction efficiency and reducing the operation risk.

In order to achieve the above purpose, the invention provides a multi-layer immobile string for combining small-displacement perforation and large-displacement fracturing, which can comprise an oil pipe, a safety joint, a multi-layer immobile string combination unit, a first-layer immobile string combination unit and a single-flow valve which are sequentially arranged from top to bottom, wherein the first-layer immobile string combination unit comprises a first-stage sliding sleeve packer, a first-stage adjusting oil pipe, a sliding sleeve type hydraulic injector and a large-diameter packer which are sequentially arranged from top to bottom; the multi-layer immobile pipe column combination unit comprises a second layer immobile pipe column combination unit, a n layer immobile pipe column combination unit and one or more immobile pipe column combination units, wherein the second layer immobile pipe column combination unit, the n layer immobile pipe column combination unit and the one or more immobile pipe column combination units are sequentially arranged from small to large in sequence, and n is a natural number larger than 1; the nth layer of fixed pipe column combination unit of the single layer level in the multilayer fixed pipe column combination unit comprises an nth level sliding sleeve packer, an nth level adjusting oil pipe and an nth level hydraulic jetting sand adding and packing integrated tool which are sequentially arranged from top to bottom; the large-drift-diameter packer can pack the stratum through the sliding sleeve type hydraulic ejector; the two-way stratum packing can be formed at the upper and lower parts of the first layer perforation position through the first layer of fixed string combination unit and the multi-layer fixed string combination unit, and the two-way stratum packing can be performed at one or more perforation positions from the second layer perforation position to the nth layer perforation position, which are continuously arranged in the sequence from the small value to the large value.

According to one or more exemplary embodiments of an aspect of the present invention, the nth stage hydraulic jetting sand adding and packing integrated tool may include a packing module, and a hydraulic jetting module, a central pipe and a lower joint sequentially disposed from top to bottom, wherein the packing module is a hollow cylinder, and is sleeved on the circumferential outer surface of the central pipe, and an upper inner wall of the packing module is connected with a lower outer wall of the hydraulic jetting module; the hydraulic jetting module is a hollow cylinder, three through holes are arranged on the outer circular wall of the hydraulic jetting module along the axial direction of the hydraulic jetting module at intervals, and the three through holes are sequentially provided with a sand outlet, an injection hole and a water hole channel from top to bottom; the size of the sand outlet is larger than that of the injection hole; the inner wall of the hydraulic jetting module is sequentially provided with a first control sliding sleeve and a second control sliding sleeve from top to bottom, the first control sliding sleeve seals and closes the sand outlet, and the second control sliding sleeve seals and closes the jetting hole and the water hole channel; a connecting gap is formed between the outer wall of the lower part of the hydraulic jetting module and the packing module, the outer wall of the central pipe is provided with a flow passage, and the connecting gap, the flow passage and the water hole passage form a hydraulic pressure transmission passage.

According to one or more exemplary embodiments of an aspect of the present invention, the reduced inner diameter of the lower joint may be formed with a seating step capable of receiving the first control sleeve and the second control sleeve which fall down during the construction process; the first sliding sleeve and the second sliding sleeve can be provided with annular grooves, shearing pins can be arranged on the circumferential outer surface of the hydraulic jetting module, the tail ends of the shearing pins are arranged in the annular grooves, the first sliding sleeve is connected with the hydraulic jetting module through the shearing pins, and the second sliding sleeve is connected with the hydraulic jetting module.

According to one or more exemplary embodiments of an aspect of the present invention, the upper and lower portions of the first control sleeve may be provided with double sets of sealing rings to form a seal with the inner wall of the hydraulic jetting module; the upper part, the lower part and the middle section of the second control sliding sleeve can be respectively provided with double groups of sealing rings so as to form a seal with the inner wall of the hydraulic jetting module.

According to one or more exemplary embodiments of an aspect of the present invention, the first-stage sliding sleeve packer and the nth-stage sliding sleeve packer may each include a packing module, and an upper joint, a central pipe and a lower joint sequentially disposed from top to bottom, where the packing module is a hollow cylinder, and is sleeved on a circumferential outer surface of the central pipe, and an upper inner wall of the packing module is connected with a lower outer wall of the hydraulic injection module; the outer wall of the upper joint is provided with a water hole channel; an inner sliding sleeve is arranged on the inner wall of the upper joint, and the inner sliding sleeve seals and closes the water hole channel; a connecting gap is formed between the outer wall of the lower part of the upper joint and the packing module, the outer wall of the central pipe is provided with a through-flow groove, and the connecting gap, the through-flow groove and the water hole channel form a hydraulic pressure transmission channel.

According to one or more exemplary embodiments of an aspect of the invention, the nth stage sliding sleeve packer may comprise an expanding packer.

According to one or more exemplary embodiments of an aspect of the present invention, the sliding sleeve type hydraulic injector may include an injector body, a control sliding sleeve, a sand outlet, and an injection hole, wherein the sand outlet and the injection hole are provided on the injector body, and the sand outlet is located above the injection hole; the control sliding sleeve is positioned on the inner wall of the ejector body, and the control sliding sleeve seals the sand outlet.

According to one or more exemplary embodiments of an aspect of the invention, the outer diameter of the large-diameter packer may be greater than a maximum outer diameter of the sliding sleeve in the sliding sleeve packer and a maximum outer diameter of the sliding sleeve in the sliding sleeve hydraulic injector.

According to one or more exemplary embodiments of an aspect of the present invention, the tubing, the safety joint, the multi-layer dead leg assembly unit, the first layer dead leg assembly unit, and the check valve may be threadably and sealingly connected to each other.

Another aspect of the present invention provides a construction method of a multi-layer stationary string combining small-displacement perforation and large-displacement fracturing, which may be implemented by combining small-displacement perforation and large-displacement fracturing as described above, the construction method may include the steps of: s1, a small-displacement perforation and a large-displacement fracturing are combined into a multi-layer stationary tubular column; s2, performing low-replacement setting on the large-drift-diameter packer; s3, performing first-layer hydraulic sand blasting perforation; s4, throwing a ball to open an inner sliding sleeve of the first-stage sliding sleeve packer and a sand outlet of the sliding sleeve type hydraulic injector; s5, carrying out first layer fracturing construction by using the double-seal single card; s6, throwing a ball to open a second control sliding sleeve of the nth stage hydraulic injection sand adding and packing integrated tool, and opening a water hole channel and an injection hole of the nth stage hydraulic injection sand adding and packing integrated tool; s7, carrying out hydraulic sand blasting perforation of the nth layer; s8, throwing a ball to open the sand outlet of the inner sliding sleeve of the nth-stage sliding sleeve packer and the nth-stage hydraulic jetting sand adding and sealing integrated tool; s9, carrying out nth layer fracturing construction by using the double-seal single card; s10, carrying out steps S6-S9 through each layer of immobile pipe column combination units of the multilayer immobile pipe column combination units, and carrying out multilayer fracturing construction; s11, performing layer-by-layer open-flow on all the constructed layer sections.

Compared with the prior art, the invention has the beneficial effects that at least one of the following contents is included:

(1) The multi-layer immobile tubular column combined by the small-displacement perforation and the large-displacement fracturing has reasonable structure, can be suitable for multi-layer or horizontal wells of the vertical wells of the oil and gas fields, and can realize the completion of multi-layer hydraulic jet fracturing construction by one drilling.

(2) The small-displacement perforation and large-displacement fracturing combined multilayer immobile string provided by the invention is adopted to carry out fracturing construction, so that the invention can replace the fire industry, improve the construction efficiency and reduce the operation risk.

(3) The hydraulic injection sand adding and packing integrated tool in the multi-layer motionless tubular column combining the small-displacement perforation and the large-displacement fracturing is integrated with the hydraulic injection sand adding module and the packing module, can realize the integration of packing stratum, hydraulic perforation and large-displacement sand adding, can realize various comprehensive application effects, and simplifies the structure of the motionless tubular column.

(4) The construction method for combining the small-displacement perforation and the large-displacement fracturing into the multi-layer stationary pipe column can realize accurate perforation fracturing of a construction layer section and complete combination of one-time drilling of the multi-layer small-displacement perforation and the large-displacement fracturing.

(5) The construction method for combining the small-displacement perforation and the large-displacement fracturing into the multi-layer stationary pipe column can effectively solve the problem of large-displacement fracturing construction.

Drawings

The foregoing and other objects and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a schematic of a small displacement perforating and large displacement fracturing combined multi-layer stationary string configuration in accordance with an exemplary embodiment of the present invention;

FIG. 2 illustrates a schematic view of a partial cross-sectional structure of an nth stage hydraulic jetting sand pack integrated tool according to an exemplary embodiment of the present invention;

FIG. 3 illustrates a schematic view of a partial cross-sectional configuration of an nth stage sliding sleeve packer according to an exemplary embodiment of the invention;

FIG. 4 shows an enlarged view of portion K of FIG. 3;

FIG. 5 illustrates a schematic structural view of a sliding sleeve hydraulic injector according to an exemplary embodiment of the present invention;

FIG. 6 shows a schematic view of the structure of a shear pin of a sliding sleeve in a ball cut fixed sliding sleeve packer;

FIG. 7 is a schematic diagram showing the structure of the inner sliding sleeve and the steel ball falling state after the shear pin of the inner sliding sleeve of the fixed sliding sleeve packer is sheared;

FIG. 8 is a schematic structural view showing a state that a shear pin of a first control slide sleeve of a fixed hydraulic injection sand packing integrated tool is sheared;

FIG. 9 is a schematic diagram showing the structure of the hydraulic injection sand packing integrated tool in a state in which a first control slide sleeve falls;

FIG. 10 illustrates a flow chart of a method of construction of a multi-layer stationary string for a combination of small-displacement perforations and large-displacement fracturing in accordance with another exemplary embodiment of the present invention.

Reference numerals:

1-oil pipe, 2-safety joint, 31-first-stage sliding sleeve packer, 311-packing module A, 312-upper joint, 313-central pipe A, 314-lower joint A, 315-water hole channel A, 316-inner sliding sleeve, 317-circlip, 318-fixed ring A, 3181-through hole I, 3182-counter bore, 319-shear pin A, 32-first-stage adjusting oil pipe, 33-sliding sleeve hydraulic injector, 34-large-diameter packer, 41-second-stage sliding sleeve packer, 42-second-stage adjusting oil pipe, 43-second-stage hydraulic injection sand packing integrated tool, 431-packing module B, 432-hydraulic injection module, 433-central pipe B, 434-lower joint B, 435-sand outlet B, 436-injection hole B, 437-water hole channel B, 438-first control sliding sleeve, 439-second control sliding sleeve, 4310-shear pin B; 5-uniflow valve; 61-injector body, 62-shear pin C, 63-control slide I, 64-sand outlet C, 65-injection hole C, 66-fixation ring C, 67-tightening screw.

Detailed Description

Hereinafter, the small-displacement perforating and large-displacement fracturing combined multilayer immobile string and the construction method thereof of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

In the description of the present application, it should be understood that the terms "middle," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," "forward," "reverse," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

The terms "first," "second," and the like are used merely for convenience of description and for convenience of distinction and should not be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

Example embodiment 1

The present exemplary embodiment provides a multi-layer stationary string for a combination of small displacement perforations and large displacement fracturing.

FIG. 1 illustrates a schematic of a small displacement perforating and large displacement fracturing combined multi-layer stationary string configuration in accordance with an exemplary embodiment of the present invention; FIG. 2 illustrates a schematic view of a partial cross-sectional structure of an nth stage hydraulic jetting sand pack integrated tool according to an exemplary embodiment of the present invention; FIG. 3 illustrates a schematic view of a partial cross-sectional configuration of an nth stage sliding sleeve packer according to an exemplary embodiment of the invention; FIG. 4 shows an enlarged view of portion K of FIG. 3; FIG. 5 illustrates a schematic structural view of a sliding sleeve hydraulic injector according to an exemplary embodiment of the present invention; FIG. 6 shows a schematic view of the structure of a shear pin of a sliding sleeve in a ball cut fixed sliding sleeve packer; FIG. 7 is a schematic diagram showing the structure of the inner sliding sleeve and the steel ball falling state after the shear pin of the inner sliding sleeve of the fixed sliding sleeve packer is sheared; FIG. 8 is a schematic structural view showing a state that a shear pin of a first control slide sleeve of a fixed hydraulic injection sand packing integrated tool is sheared; fig. 9 shows a schematic structural diagram of a hydraulic injection sand packing integrated tool in a state that a first control sliding sleeve falls. The small-displacement perforating and large-displacement fracturing combined multi-layer stationary string of the present exemplary embodiment is described below in conjunction with fig. 1-9. The top-to-bottom direction in the specification is the left-to-right direction in fig. 2, 3, and 5 to 9.

The multi-layer immobile string combining the small-displacement perforation and the large-displacement fracturing mainly comprises an oil pipe, a safety joint, a multi-layer immobile string combination unit, a first-layer immobile string combination unit and a single-flow valve which are sequentially arranged from top to bottom. Here, the tubing, safety joint, multi-layer dead leg assembly unit, first layer dead leg assembly unit, and single flow valve may be sealingly connected to each other by threads.

The first layer of fixed tubular column combination unit comprises a first-stage sliding sleeve packer, a first-stage adjusting oil pipe, a sliding sleeve type hydraulic injector and a large-diameter packer which are sequentially arranged from top to bottom; the first-stage sliding sleeve packer and the nth-stage sliding sleeve packer have the same structure.

The multi-layer immobile column combination unit comprises a second layer immobile column combination unit, an n layer immobile column combination unit and one or more immobile column combination units which are sequentially arranged from bottom to top in sequence from small to large, wherein n is a natural number which is larger than 1.

The nth layer of fixed pipe column combination unit of the single layer level in the multilayer fixed pipe column combination unit comprises an nth level sliding sleeve packer, an nth level adjusting oil pipe and an nth level hydraulic jetting sand adding and packing integrated tool which are sequentially arranged from top to bottom. The hydraulic jetting sand packing integrated tool in the multilayer immobile pipe column combined unit has the same structure.

The large-drift-diameter packer can pack the stratum through the sliding sleeve type hydraulic ejector; the two-way stratum packing can be formed at the upper and lower parts of the first layer perforation position through the first layer of fixed string combination unit and the multi-layer fixed string combination unit, and the two-way stratum packing can be performed at one or more perforation positions from the second layer perforation position to the nth layer perforation position, which are continuously arranged in the sequence from the small value to the large value.

In the present exemplary embodiment, the nth stage hydraulic jetting sand packing integrated tool may include a packing module, and a hydraulic jetting module, a center pipe, and a lower joint disposed in this order from top to bottom. The packing module is a hollow cylinder, is sleeved on the circumferential outer surface of the central tube, and the inner wall of the upper part of the packing module is connected with the outer wall of the lower part of the hydraulic jetting module; the hydraulic jetting module is a hollow cylinder, three through holes are arranged on the outer circular wall of the hydraulic jetting module along the axial direction of the hydraulic jetting module at intervals, and the three through holes are sequentially provided with a sand outlet, an injection hole and a water hole channel from top to bottom; the size of the sand outlet is larger than that of the injection hole; the inner wall of the hydraulic jetting module is sequentially provided with a first control sliding sleeve and a second control sliding sleeve from top to bottom, the first control sliding sleeve seals and closes the sand outlet, and the second control sliding sleeve seals and closes the jetting hole and the water hole channel; a connecting gap is formed between the outer wall of the lower part of the hydraulic jetting module and the packing module, the outer wall of the central pipe is provided with a flow passage, and the connecting gap, the flow passage and the water hole passage form a hydraulic pressure transmission passage.

In the present exemplary embodiment, the nth stage sliding sleeve packer may include a packing module and an upper joint, a center tube, and a lower joint disposed sequentially from top to bottom. The packing module is a hollow cylinder, is sleeved on the circumferential outer surface of the central tube, and the inner wall of the upper part of the packing module is connected with the outer wall of the lower part of the hydraulic jetting module; the outer wall of the upper joint is provided with a water hole channel; an inner sliding sleeve is arranged on the inner wall of the upper joint, and the inner sliding sleeve seals and closes the water hole channel; a connecting gap is formed between the outer wall of the lower part of the upper joint and the packing module, the outer wall of the central pipe is provided with a through-flow groove, and the connecting gap, the through-flow groove and the water hole channel form a hydraulic pressure transmission channel.

In the present exemplary embodiment, the number of layers of the multi-layer immobile string combination unit of the multi-layer immobile string combining the small-displacement perforation and the large-displacement fracturing may be added according to the number of layers of the construction well. The number of the stages of the immobile pipe columns can be changed according to the number of the layers of the construction well, and the immobile pipe columns can be a first-stage immobile pipe column, a second-stage immobile pipe column, a third-stage immobile pipe column, a fourth-stage immobile pipe column and the like. The first-stage immobile string has an oil pipe, a safety joint, a first-layer immobile string combination unit and a single flow valve. The second-level immovable pipe column is additionally provided with a second-layer immovable pipe column combination unit on the basis of the first-level immovable pipe column structure. The third-layer immovable pipe column is additionally provided with a third-layer immovable pipe column combination unit on the basis of the second-layer immovable pipe column. The fourth-level stationary pipe column is additionally provided with a fourth-layer stationary pipe column combination unit on the basis of the third-level stationary pipe column, so that the multi-layer stationary pipe column is combined with the small-displacement perforation and the large-displacement fracturing.

The structure of the stationary pipe column of the invention is described below by taking a multi-layer stationary pipe column of two-stage small-displacement perforation and large-displacement fracturing as an example, namely a two-stage stationary pipe column:

as shown in fig. 1, the secondary stationary pipe string may include an oil pipe 1, a safety joint 2, a second stage sliding sleeve packer 41, a second stage trim oil pipe 42, and a second stage hydraulic jet sand packing integrated tool 43, a first stage sliding sleeve packer 31, a first stage trim oil pipe 32, a sliding sleeve hydraulic injector 33, a large-diameter packer 34, and a single flow valve 5, which are disposed in this order from top to bottom. Here, all the devices in the secondary stationary pipe string can be connected by screw thread sealing.

The second-level stationary pipe column relates to an oil pipe and a safety joint, which can be a disclosed tool in the field of oil and gas field development, the oil pipe is used for connecting the pipe column to a wellhead through well conditions, and the safety joint can ensure that the pipe column can be safely pulled out when the pipe column is blocked and cannot be pulled out. The safety joint is connected to the upper end of the fixed tubular column tool, only the oil pipe is arranged on the safety joint, the fixed tubular column is provided with n stages, and the safety joint is connected to the n-th stage sliding sleeve packer.

The whole structure of the packer can be an expansion type packer, a water hole is designed on the packer, a launder is designed on a central pipe for transmitting hydraulic pressure required by setting of the packer, a sliding sleeve is designed in the upper joint for blocking the pressure, and a shear pin can be arranged on the sliding sleeve, so that the setting of the packer is controllable. When the lower layer is constructed, the sliding sleeve packer is not started, when the layer section is constructed, the sliding sleeve is opened by throwing steel balls with corresponding dimension specifications to hold pressure and shear pins, so that the sliding sleeve packer enters a working state, and at the moment, a certain throttling pressure difference is provided, so that the packer can be reliably set.

The hydraulic jetting sand adding sealing integrated tool is provided with a hydraulic jetting module and a sealing module, can integrate jetting, sand adding and sealing integrated functions, is provided with an injection hole and a sand outlet, is controlled to be opened and closed by two stages of different sliding sleeves in the integrated tool respectively, can be opened simultaneously with the injection hole of the hydraulic jetting module after a second sliding sleeve is opened by a ball throwing shearing pin, and can be used for jetting at the injection hole to generate throttling to enable the tool to be sealed when the perforation is finished and needs to be fractured, and can also be opened by throwing balls to open the first sliding sleeve to open the sand outlet so as to realize large-displacement sand adding fracturing in an oil pipe.

The hydraulic ejector is used for hydraulic sand blasting perforation and fracturing construction of a first layer of the fixed pipe column, a sliding sleeve is designed in the hydraulic ejector, a sand outlet is plugged by the sliding sleeve, and after hydraulic sand blasting perforation is carried out through an injection hole, when sand adding fracturing construction is needed, the sand outlet can be opened through ball throwing and pin shearing, so that sand adding fracturing displacement is improved.

In the present exemplary embodiment, as shown in fig. 5, the sliding sleeve type hydraulic injector may include an injector body 61, a fixing ring C66, a fastening screw 67, a shear pin C62, a control sliding sleeve I63, a sand outlet C64, and an injection hole C65. Wherein, sand outlet C64 and jet hole C65 are set up on sprayer body 61, and sand outlet C64 is located jet hole C65 top. The control sliding sleeve I63 is arranged in the inner cavity of the ejector body 61, the control sliding sleeve I63 is fixed by the shearing pin C62, and the sand outlet C64 is blocked by the control sliding sleeve I63. The fixing ring C66 is arranged in the inner cavity of the injector body 61 and is positioned above the control sliding sleeve I63, and fastening screws 67 are arranged on the wall of the injector body 61 to fix the fixing ring C66.

Further, 4 spray holes and 2 sand outlets can be formed in the sprayer body, and the two sand outlets are symmetrical and are different in phase angle distribution of 60 degrees.

The sliding sleeve type hydraulic injector of the invention is different from the conventional sliding sleeve type hydraulic injector in that: the sliding sleeve type hydraulic injector is provided with the injection hole and the sand outlet, wherein the sliding sleeve is only used for sealing the sand outlet, the hydraulic sand blasting perforation function of the injection hole can be normally executed before the sliding sleeve is opened, and the sliding sleeve is opened to open the sand outlet through throwing a ball when entering a fracturing flow after perforation, so that the sand adding discharge capacity can be improved compared with the conventional fracturing construction in the fracturing process, the conventional sliding sleeve type hydraulic injector is only provided with the injection hole, the injection hole is sealed through the sliding sleeve, and the whole hydraulic injector does not work before the sliding sleeve is opened.

The inner diameter of the large-diameter packer related to the fixed tubular column is increased by 10-15% relative to the K344 expansion packer disclosed in the oil-gas field development field, and the large-diameter packer is used for ensuring the sliding sleeve to pass through. The sliding sleeve can fall into the position of the single flow valve at the tail end of the pipe column through the central pipe while the sand passing amount is increased. The external diameter of the large-drift-diameter packer is required to be larger than the maximum external diameter of the sliding sleeve in the sliding sleeve packer and the maximum external diameter of the sliding sleeve in the sliding sleeve type hydraulic injector.

The utility model provides a uniflow valve that relates to in the motionless tubular column, it is the well-known instrument in the field of oil gas field development, mainly used in the work progress, shutoff oil pipe internal pressure when oil pipe forward pressurization provides the instrument tail end reverse circulation passageway simultaneously.

If the second-level fixed tubular column is adopted for construction, when the first layer is constructed, the tool used for the second-level construction is in an inactive state, when the first-level hydraulic sand blasting perforation is carried out, the jet hole of the sliding sleeve type hydraulic injector generates throttling pressure difference, so that the large-drift diameter packer seals the stratum, after the perforation is finished, the sliding sleeve corresponding to the size specification steel ball is put into the first-level sliding sleeve packer, the sliding sleeve at the water hole channel of the first-level sliding sleeve packer and the sliding sleeve at the sand outlet of the sliding sleeve type hydraulic injector are opened, the bidirectional stratum sealing is formed at the position of the first-level perforation up and down through the first-level sliding sleeve packer, the stratum is prevented from being channeling in the fracturing process, and the fracturing displacement of the oil pipe can be improved through the fracturing of the sand outlet opened by the sliding sleeve type hydraulic injector.

When the second layer is constructed, the second control sliding sleeve of the second-stage hydraulic injection sand adding and sealing integrated tool can be opened by throwing the steel ball I, a water hole channel and an injection hole of the second-stage hydraulic injection sand adding and sealing integrated tool are opened, after the second control sliding sleeve is opened, the second control sliding sleeve falls to the lower joint of the second-stage hydraulic injection sand adding and sealing integrated tool, and sealing and plugging oil pipe pressure is formed through the second control sliding sleeve and the steel ball I, so that the tools used for the first layer construction are all in an inactive state. When the second layer is perforated, throttle pressure difference is generated through the jet hole, the pressure difference is transmitted to a packing module of the second-stage hydraulic jet sand-adding packing integrated tool through a water hole channel, so that the second-stage hydraulic jet sand-adding packing integrated tool packs a lower stratum under construction, after perforation is finished, a steel ball II is thrown into, a first control sliding sleeve at a sand outlet of the second-stage sliding sleeve packer inner sliding sleeve and the second-stage hydraulic jet sand-adding packing integrated tool is simultaneously opened, bidirectional stratum packing is carried out at the perforation position of the second layer, and large-displacement oil pipe fracturing can be carried out through the sand outlet during fracturing.

The invention has the characteristic of opening the single-ball double-sliding sleeve, taking a secondary immovable pipe column as an example, the sliding sleeve of the first-stage sliding sleeve packer and the sliding sleeve of the sliding sleeve type hydraulic injector can be opened by one-time ball injection, and the sliding sleeve of the second-stage sliding sleeve packer and the first control sliding sleeve of the second-stage hydraulic injection sand-adding packing integrated tool can be opened by one-time ball injection.

In this exemplary embodiment, the present invention has a structural design of single-ball control double-sliding sleeve opening, and the specific working principle thereof may include: taking a second-stage non-moving tubular column as an example, when the inner sliding sleeve of the second-stage sliding sleeve packer is opened through ball throwing in the second-stage non-moving tubular column, the state that the shearing pin of the inner sliding sleeve is sheared and fixed by the pressure of the oil pipe is corresponding to the ball throwing shown in fig. 6. The inner sliding sleeve and the steel ball fall along the inner diameter of the central tube of the second-stage sliding sleeve packer, and the state corresponds to the state of structural representation of the state of the inner sliding sleeve and the steel ball falling after the shear pin for fixing the inner sliding sleeve is sheared as shown in fig. 7. When the inner sliding sleeve falls to the upper end of the first control sliding sleeve of the second-stage hydraulic jetting sand-adding and packing integrated tool, the tail end conical surface of the inner sliding sleeve is attached to the conical surface of the ball seat of the first control sliding sleeve to form a seal, and at the moment, the inner sliding sleeve and the steel ball correspondingly shown in fig. 8 fall to the first control sliding sleeve to cut off the shearing pin of the first control sliding sleeve. The oil pipe can be suppressed again, the shearing pin of the first control sliding sleeve is sheared off, the steel ball falls down together with the inner sliding sleeve and the first control sliding sleeve and is located at the lower joint, the two sliding sleeves are opened simultaneously after one ball injection is completed, and at the moment, the first control sliding sleeve corresponding to the state shown in fig. 9 falls down to the lower joint. The structure and the principle that the double sliding sleeves are controlled to be opened by the single ball can reduce the ball throwing times of the fixed tubular column, and the construction efficiency is saved. It is worth mentioning that, above-mentioned little discharge capacity perforation and big discharge capacity fracturing allies oneself with multilayer motionless tubular column when first layer construction, the design structure that the two sliding sleeves of a ball control are opened can also be adopted with sliding sleeve formula hydraulic injector to the first level sliding sleeve packer that uses, because its theory of operation is the same, and this is unnecessary.

In the present exemplary embodiment, the hydraulic jetting sand pack integrated tool in the multistage stationary pipe string is identical in structure. As shown in fig. 2, the second stage hydrajetting sanded packing integrated tool may include a hydrajetting module 432, a center tube B433, a lower sub B434, a first control slip 438, a second control slip 439, a sand outlet B435, a shear pin B4310, an injection hole B436, a water hole channel B437, and a packing module B431.

The hydraulic jetting module 432 is a hollow cylinder, and the outer circumferential surface of the hydraulic jetting module 432 is axially provided with three through holes with different sizes, the three through holes are symmetrically and uniformly distributed, threads are arranged in the three through holes, and the three through holes are a sand outlet B435, a jet hole B436 and a water hole channel B437. The second control sleeve 439 and the first control sleeve 438 are hollow cylinders, and the outer circle of the second control sleeve is the same as the inner diameter of the hydraulic jetting module 432. The two ends of the first control sliding sleeve are of double-group sealing ring structures, and two sealing rings are respectively arranged at the two ends and the middle part of the second control sliding sleeve. The center positions of the two control sliding sleeves are provided with annular grooves, and the two control sliding sleeves are arranged on the inner wall of the inner hole of the hydraulic injection module according to the directions of the first control sliding sleeve and the second control sliding sleeve. The shearing pin B4310 can be made of brass material and is connected with the hydraulic spraying module 432 through threads, meanwhile, the tail end of the shearing pin B4310 is arranged in the annular groove, and the two control sliding sleeves are respectively and fixedly connected with the hydraulic spraying module 432. The second control sliding sleeve 439 seals the injection hole B436 and the water hole channel B437 through the three groups of sealing rings, and the first control sliding sleeve 438 seals the sand outlet B435 through the two groups of sealing rings at two ends. The pressure cannot be transmitted outwards through this position until the control slide is opened. The hydraulic jetting module 432 is connected with the packing module B431 through external threads and is connected with the central pipe B433 through internal threads. The packing module B may be an expanding packing element structure that creates an expanding packing exterior space when hydraulic pressure is transferred to the inside of the packing module B. The central tube B can be of a long cylindrical structure, sealing rings are arranged at two ends of the central tube B to seal pressure, the inner diameter of the central tube B is consistent with that of the hydraulic jet module, the outer circular surface of the central tube B is provided with a flow passage, and the three parts form a hydraulic pressure transmission channel, namely a connection gap between the flow passage and the sealing module B and the hydraulic jet module and a water hole channel B. Lower fitting B434 may be threadably coupled to center tube B433. The inner diameter of the lower joint B is reduced at the tail end of the integrated tool to form a seating step, and the seating step can be used for receiving a first control sliding sleeve and a second control sliding sleeve which fall down after being sheared in the construction process.

In this exemplary embodiment, the working principle of the hydraulic jetting sand packing integrated tool of the present invention may include: under the condition that the first control sliding sleeve and the second control sliding sleeve are not opened, the hydraulic injection sand adding and packing integrated tool does not work. When the steel ball I falls to the upper end of the second control sliding sleeve, the shearing pin of the second control sliding sleeve and the hydraulic jetting module can be sheared and fixed through the oil pipe to hold pressure, the steel ball I and the second control sliding sleeve fall to a seating step position generated by the inner reducing of the lower joint along the central pipe of the tool, the pressure in the plugged oil pipe cannot be transmitted downwards, meanwhile, the injection hole is opened through the second control sliding sleeve, the pressure trap at the water hole channel is released, the pressure of the oil pipe is released along the injection hole to form a throttling pressure difference, the liquid with the throttling pressure difference passes through the water hole channel, the sealing module is connected with the hydraulic jetting module through a gap and the central pipe to enter the sealing module through a launder, so that the sealing module glue barrel expands to seal a constructed stratum, and the hydraulic blasting perforation operation can be carried out through the injection hole. When the steel ball II is put into, after the shearing pin of the first control sliding sleeve and the hydraulic injection module is sheared off, the first control sliding sleeve falls along the inner diameter of the central pipe and is located at the upper end of the second control sliding sleeve, at the moment, the pressure trap at the sand outlet B is relieved because the first control sliding sleeve is opened, and the discharge capacity of the oil pipe can be improved to carry out large-displacement fracturing because the drift diameter of the sand outlet B is far larger than that of the injection hole, and the effect of the hydraulic injection sand-adding packing integrated tool for packing stratum still exists because of throttling pressure difference.

In this exemplary embodiment, the sliding sleeve packer in the multistage stationary string is identical in structure, except that: in different immobile string levels, the internal sliding sleeve path of the sliding sleeve packer is different. As shown in fig. 3, the first stage sliding sleeve packer may include a packing module a 311, an upper sub 312, a base pipe a 313, a lower sub a 314, a water bore passage a 315, an inner sleeve 316, a circlip 317, a retaining ring a318, and a shear pin a 319.

The upper joint 312 and the packing module a 311 may be connected by threads, and the internal pressure may be trapped at the threaded connection by a sealing ring. The upper joint is internally provided with a step hole which is slightly larger than the inner diameter and is not the diameter besides the inner diameter, and is used for installing the fixing ring A. One end of the fixed ring A is contacted with the step surface of the inner hole of the upper joint. The fixed ring A318 is fixed after being provided with a circlip 317 through a retainer groove arranged at the front end of the inner hole of the upper joint 312. As shown in fig. 4, the fixing ring a may be provided with coaxial counter bore 3182 and through hole I3181 along radial symmetry of the fixing ring a itself, the counter bore 3182 and the through hole I3181 are both provided on the fixing ring a, and the counter bore 3182 is above the through hole I3181. The inner diameter of the counter bore is larger than the inner diameter of the through hole I. The purpose of setting up counter bore and through-hole I is used for installing shear pin A, and through-hole I is used for being connected interior sliding sleeve and solid fixed ring A through shear pin A shearing end, and the counter bore is used for installing the stiff end of shear pin, prevents that the shear pin accident from dropping. The diameter of the counter bore is larger than that of the through hole. As shown in fig. 3, the inner slide 316 is mounted inside the upper joint 312. The inner sliding sleeve 316 is provided with two sealing rings positioned at the left and right sides thereof to seal the water hole channel A315. The front end of the inner sliding sleeve is provided with an annular groove, a shearing pin A319 can be arranged at the coaxial hole of the fixed ring A318, and the tail end of the shearing pin A319 stretches into the annular groove to fix the inner sliding sleeve 316 with the fixed ring A318. The central tube A313 can be of a long cylindrical structure, sealing rings are arranged at the upper end and the lower end of the central tube A313 to seal pressure, and a through-flow groove is formed in the outer cylindrical surface of the central tube A313. The hydraulic pressure transmission channel is formed by the three parts of the flow trough, the connecting gap between the packing module A and the upper joint and the water hole channel A. The packing module a may be an expanding packing element structure that creates an expanding packing exterior space when hydraulic pressure is transferred to the inside of the packing module a. The end of the lower sub a 314 may be provided with external threads for connection to other tools.

In this exemplary embodiment, the working principle of the sliding sleeve packer of the present invention may include:

the sliding sleeve packer controls whether the sliding sleeve packer is in a working state or not through the sliding sleeve, so that the sliding sleeve packer can be selectively opened, and the inner sliding sleeve of the sliding sleeve packer is different in drift diameter in different fixed string layers. Under the initial state, the sliding sleeve packer is capable of trapping the pressure at the water hole channel through the inner sliding sleeve, when the stratum is required to be sealed and isolated, steel balls of corresponding specifications are put into the wellhead to be located at the upper end of the inner sliding sleeve, the inner sliding sleeve is enabled to fall along the inner diameter of the central tube through the shearing pin at the joint of the oil pipe pressure-blocking shearing fixing ring and the inner sliding sleeve, at the moment, the water hole channel is opened, the pressure in the oil pipe can be transmitted into the sealing and isolating module through the water hole channel, the gap between the upper joint and the sealing and isolating module and the liquid transmission channel formed by the central tube through the flow groove, so that the sealing and isolating module rubber cylinder is expanded and isolated to the constructed stratum.

Example embodiment 2

The embodiment provides a construction method for a multi-layer stationary pipe column combining small-displacement perforation and large-displacement fracturing.

FIG. 10 illustrates a flow chart of a method of construction of a multi-layer stationary string for a combination of small-displacement perforations and large-displacement fracturing in accordance with another exemplary embodiment of the present invention. The construction method of the small-displacement perforating and large-displacement fracturing combined multilayer stationary string of the present exemplary embodiment is described below with reference to fig. 10.

The construction method of the multilayer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing can be realized through the multilayer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing in the above-mentioned exemplary embodiment 1.

The construction method of the multi-layer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing of the embodiment can comprise the following steps:

s1, a small-displacement perforation and a large-displacement fracturing are combined into a multi-layer stationary tubular column.

S2, performing low-replacement setting on the large-drift-diameter packer.

S3, performing first-layer hydraulic sand blasting perforation.

S4, throwing balls to open an inner sliding sleeve of the first-stage sliding sleeve packer and a sand outlet of the sliding sleeve type hydraulic injector.

S5, carrying out first layer fracturing construction by the double-seal single card.

S6, throwing a ball to open a second control sliding sleeve of the nth stage hydraulic injection sand adding and packing integrated tool, and opening a water hole channel and an injection hole of the nth stage hydraulic injection sand adding and packing integrated tool.

S7, carrying out hydraulic sand blasting perforation of the nth layer.

S8, throwing a ball to open the sand outlet of the inner sliding sleeve and the nth hydraulic jetting sand adding and sealing integrated tool of the nth sliding sleeve packer.

S9, carrying out n-th layer fracturing construction by using the double-seal single card.

S10, carrying out steps S6-S9 through each layer of fixed pipe column combination units of the multi-layer fixed pipe column combination units, and carrying out multi-layer fracturing construction.

S11, performing layer-by-layer open-flow on all the constructed layer sections.

The construction method of the invention can comprise the following steps:

as shown in fig. 10, the construction is performed using a secondary or higher order immobile string, and the construction method may include the steps of: and (5) placing a fixed pipe column, and positioning and depth correction. And (5) performing low-replacement setting on the large-diameter packer. A first layer of hydro-abrasive perforations is performed. The ball is thrown to open the inner sliding sleeve of the sliding sleeve packer (namely the first-stage sliding sleeve packer) and the control sliding sleeve of the sliding sleeve type hydraulic injector, and the sand outlet of the sliding sleeve type hydraulic injector is opened. And carrying out first layer fracturing construction by the double-seal single card. And (3) throwing a ball to open a second control sliding sleeve of the second-stage hydraulic injection sand adding and packing integrated tool, and opening a water hole channel and an injection hole of the second-stage hydraulic injection sand adding and packing integrated tool. And carrying out second-layer hydraulic sand blasting perforation. And (3) throwing a ball to open the inner sliding sleeve of the second-stage sliding sleeve packer and the first control sliding sleeve of the second-stage hydraulic injection sand adding and packing integrated tool, and opening a sand outlet of the second-stage hydraulic injection sand adding and packing integrated tool. And carrying out second layer fracturing construction by the double-seal single card. If more stages exist, perforation fracturing construction is continued. And (5) performing layer-by-layer open-flow on all the constructed layer sections.

Specifically, the construction is carried out by adopting a secondary and above-level immobile tubular column, and the construction method can comprise the following steps:

1. and (3) setting a fixed pipe column tool according to the design construction level, measuring the length of the pipe column, correcting the depth, and determining that the pipe column is set to the design construction position.

2. And (3) performing first-layer fixed tubular column construction, performing low-level replacement according to the construction design, generating throttling pressure difference at the sliding sleeve type hydraulic injector, and setting the large-diameter packer.

3. And carrying out hydraulic sand blasting perforation of the first layer, and replacing the first layer in place after perforation is completed.

4. Putting into a steel ball with the corresponding size specification of the first stage, opening an inner sliding sleeve of a first-stage sliding sleeve packer and a sand outlet of a sliding sleeve type hydraulic injector, sealing an upper annular space of a pipe column by the first-stage sliding sleeve packer, sealing a lower annular space of the pipe column by a large-diameter packer, and forming a double-sealing single-clamp construction mode to prevent a channeling-pressing interval.

5. And carrying out first layer fracturing construction, and carrying out large-displacement sand adding fracturing through a sand outlet of the sliding sleeve type hydraulic ejector until the first layer sand adding fracturing construction is completed.

6. And (3) performing second-stage fixed tubular column construction, putting a steel ball I into the second control sliding sleeve of the second-stage hydraulic injection sand-adding packing integrated tool, opening a water hole channel and an injection hole of the integrated tool, at the moment, all parts in the first-stage tubular column are in an inactive state, and improving the injection displacement of the oil pipe to the perforation displacement so as to enable the packing unit to finish setting and packing the constructed stratum.

7. The second section of hydraulic sand blasting perforation is carried out through the jet hole of the hydraulic sand blasting packing integrated tool according to the design, and the perforation needs to be replaced in place after the perforation is completed.

8. And (3) putting the steel ball II into the pipe, opening the inner sliding sleeve of the second-stage sliding sleeve packer and the sand outlet of the second-stage hydraulic injection sand adding and packing integrated tool, and packing the annular space on the pipe column by the second-stage sliding sleeve packer at the moment, and packing the annular space by the second-stage hydraulic injection sand adding and packing integrated tool packing unit to form a double-packing single clamp.

9. And (3) sand fracturing is carried out through a sand outlet opened by the second-stage hydraulic jetting sand adding and packing integrated tool, and the second-layer construction is completed.

10. The number of the immobile pipe columns can be continuously added according to the number of the layers of the construction well, and the immobile pipe columns can be a first-stage immobile pipe column, a second-stage immobile pipe column, a third-stage immobile pipe column, a fourth-stage immobile pipe column and the like. If more stages exist, repeating the steps 6-9, and carrying out subsequent fixed pipe column construction through sliding sleeve packers and the like of corresponding stages until the fracturing construction is completed after the layers are designed.

11. And (5) performing layer-by-layer open-flow on all the constructed layer sections.

In summary, the advantages of the present invention include at least one of the following:

(1) The multi-layer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing can realize the combined construction of the small-displacement perforation and the large-displacement fracturing of the multi-layer stationary pipe column, the wellhead pressure is low when the small-displacement perforation is adopted, the well control risk is low, the stratum transformation effect is good after the perforation is finished through the large-displacement fracturing, and the overall performance is superior to that of the traditional hydraulic sand blasting perforation fracturing.

(2) The multi-layer stationary pipe column combining the small-displacement perforation and the large-displacement fracturing can replace the construction mode of 'firepower perforation-scraping-fracturing' of the conventional stationary pipe column, reduce the risk of fire work operation, and originally require three drills to realize fracturing construction, and realize perforation and fracturing combination by one drill at present, so that the construction efficiency is improved.

(3) The invention provides a control mode of opening single-ball double-sliding sleeve for a small-displacement perforation and large-displacement fracturing combined multilayer immobile pipe string, which comprises a sliding sleeve of a sliding sleeve packer, a control sliding sleeve of a hydraulic injection sand packing integrated tool, a sliding sleeve of the sliding sleeve packer and a sliding sleeve of a sliding sleeve type hydraulic injector, wherein the two sliding sleeves are controlled to be simultaneously opened through one-time ball throwing control, so that the ball throwing times of the immobile pipe string are reduced, and the construction steps are simplified.

(4) The multi-layer immobile string combining the small-displacement perforation and the large-displacement fracturing comprises a hydraulic injection sand adding and packing integrated tool, and the hydraulic injection sand adding module and the packing module are integrated in the tool, so that the integration of stratum packing, hydraulic perforation and large-displacement sand adding can be realized, multiple purposes of one tool are realized, and the immobile string structure is simplified.

(5) The multi-layer immobile string combining the small-displacement perforation and the large-displacement fracturing comprises the sliding sleeve packer, the sliding sleeve packer in different levels of the immobile string has different sliding sleeve inner diameters, the setting water hole is plugged by the sliding sleeve, and the selective opening of the packer can be realized.

(6) The multi-layer immobile tubular column combined by the small-displacement perforation and the large-displacement fracturing provided by the invention has a scientific and reasonable structure, and can be well applied to multi-layer or horizontal wells of the vertical wells of the oil and gas fields.

(7) The construction method for combining the small-displacement perforation and the large-displacement fracturing into the multilayer stationary pipe column can realize accurate perforation fracturing of a construction layer section, and the multilayer small-displacement perforation and the large-displacement fracturing can be drilled once.

While the small-displacement perforating and large-displacement fracturing combined multilayer immobile string and method of construction thereof of the present invention have been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. A multilayer stationary pipe column combining small-displacement perforation and large-displacement fracturing is characterized in that the stationary pipe column comprises an oil pipe, a safety joint, a multilayer stationary pipe column combination unit, a first layer stationary pipe column combination unit and a single-flow valve which are sequentially arranged from top to bottom,

The first layer of fixed tubular column combination unit comprises a first-stage sliding sleeve packer, a first-stage adjusting oil pipe, a sliding sleeve hydraulic injector and a large-diameter packer which are sequentially arranged from top to bottom;

the multi-layer immobile pipe column combination unit comprises a second layer immobile pipe column combination unit, a n layer immobile pipe column combination unit and one or more immobile pipe column combination units, wherein the second layer immobile pipe column combination unit, the n layer immobile pipe column combination unit and the one or more immobile pipe column combination units are sequentially arranged from small to large in sequence, and n is a natural number larger than 1;

the nth layer of fixed pipe column combination unit of the single layer level in the multilayer fixed pipe column combination unit comprises an nth level sliding sleeve packer, an nth level adjusting oil pipe and an nth level hydraulic jetting sand adding and packing integrated tool which are sequentially arranged from top to bottom;

the large-drift-diameter packer can pack the stratum through the sliding sleeve type hydraulic ejector;

the two-way stratum packing can be formed at the upper and lower parts of the first layer perforation position through the first layer of fixed string combination unit and the multi-layer fixed string combination unit, and the two-way stratum packing can be performed at one or more perforation positions from the second layer perforation position to the nth layer perforation position, which are continuously arranged in the sequence from the small value to the large value.

2. The multi-layer stationary string for combined operation of small-displacement perforation and large-displacement fracturing according to claim 1, wherein the nth-stage hydraulic jet sand-adding packing integrated tool comprises a packing module, a hydraulic jet module, a central pipe and a lower joint which are sequentially arranged from top to bottom,

The packing module is a hollow cylinder, is sleeved on the circumferential outer surface of the central tube, and the inner wall of the upper part of the packing module is connected with the outer wall of the lower part of the hydraulic jetting module;

the hydraulic jetting module is a hollow cylinder, three through holes are arranged on the outer circular wall of the hydraulic jetting module along the axial direction of the hydraulic jetting module at intervals, and the three through holes are sequentially provided with a sand outlet, an injection hole and a water hole channel from top to bottom; the size of the sand outlet is larger than that of the injection hole;

the inner wall of the hydraulic jetting module is sequentially provided with a first control sliding sleeve and a second control sliding sleeve from top to bottom, the first control sliding sleeve seals and closes the sand outlet, and the second control sliding sleeve seals and closes the jetting hole and the water hole channel;

a connecting gap is formed between the outer wall of the lower part of the hydraulic jetting module and the packing module, the outer wall of the central pipe is provided with a flow passage, and the connecting gap, the flow passage and the water hole passage form a hydraulic pressure transmission passage.

3. The multi-layer stationary string for combined operation of small-displacement perforation and large-displacement fracturing according to claim 2, wherein the inner diameter of the lower joint is reduced to form a seating step, and the seating step can receive a first control sliding sleeve and a second control sliding sleeve which fall down in the construction process;

the hydraulic injection device comprises a hydraulic injection module, a first sliding sleeve and a second sliding sleeve, wherein the first sliding sleeve and the second sliding sleeve are provided with annular grooves, shearing pins are arranged on the circumferential outer surface of the hydraulic injection module, the tail ends of the shearing pins are arranged in the annular grooves, the first sliding sleeve is connected with the hydraulic injection module through the shearing pins, and the second sliding sleeve is connected with the hydraulic injection module.

4. The multi-layer stationary string for combined operation of small-displacement perforation and large-displacement fracturing according to claim 2, wherein the upper part and the lower part of the first control sliding sleeve are provided with double groups of sealing rings so as to form a seal with the inner wall of the hydraulic jetting module; the upper part, the lower part and the middle section of the second control sliding sleeve are respectively provided with double groups of sealing rings so as to form sealing with the inner wall of the hydraulic jetting module.

5. The multi-layer stationary string for combined operation of small-displacement perforation and large-displacement fracturing according to claim 1, wherein the first-stage sliding sleeve packer and the nth-stage sliding sleeve packer comprise a packing module, an upper joint, a central tube and a lower joint which are sequentially arranged from top to bottom,

the packing module is a hollow cylinder, is sleeved on the circumferential outer surface of the central tube, and the inner wall of the upper part of the packing module is connected with the outer wall of the lower part of the hydraulic jetting module;

the outer wall of the upper joint is provided with a water hole channel;

an inner sliding sleeve is arranged on the inner wall of the upper joint, and the inner sliding sleeve seals and closes the water hole channel;

a connecting gap is formed between the outer wall of the lower part of the upper joint and the packing module, the outer wall of the central pipe is provided with a through-flow groove, and the connecting gap, the through-flow groove and the water hole channel form a hydraulic pressure transmission channel.

6. The small displacement perforating and large displacement fracturing combined multi-layer stationary string of claim 5, wherein the nth stage sliding sleeve packer comprises an expanding packer.

7. The combination small-displacement perforating and large-displacement fracturing multilayer stationary pipe column of claim 1, wherein the sliding sleeve type hydraulic injector comprises an injector body, a control sliding sleeve, a sand outlet and an injection hole, wherein,

the sand outlet and the injection hole are arranged on the injector body, and the sand outlet is positioned above the injection hole;

the control sliding sleeve is positioned on the inner wall of the ejector body, and the control sliding sleeve seals the sand outlet.

8. The multi-layer stationary string of small-displacement perforating and large-displacement fracturing combined operation of claim 1, wherein the outer diameter of the large-drift diameter packer is greater than the largest outer diameter of the sliding sleeve in the sliding sleeve packer and the largest outer diameter of the sliding sleeve in the sliding sleeve hydraulic injector.

9. The multi-layer stationary string for combined use of small-displacement perforations and large-displacement fracturing according to claim 1, wherein the tubing, safety joint, multi-layer stationary string combination unit, first-layer stationary string combination unit and single flow valve are in threaded sealing connection with each other.

10. A construction method of a multilayer stationary pipe string combining small-displacement perforation and large-displacement fracturing, which is characterized in that the construction method is realized by the multilayer stationary pipe string combining small-displacement perforation and large-displacement fracturing according to any one of claims 1 to 9, and the construction method comprises the following steps:

S1, a small-displacement perforation and a large-displacement fracturing are combined into a multi-layer stationary tubular column;

s2, performing low-replacement setting on the large-drift-diameter packer;

s3, performing first-layer hydraulic sand blasting perforation;

s4, throwing a ball to open an inner sliding sleeve of the first-stage sliding sleeve packer and a sand outlet of the sliding sleeve type hydraulic injector;

s5, carrying out first layer fracturing construction by using the double-seal single card;

s6, throwing a ball to open a second control sliding sleeve of the nth stage hydraulic injection sand adding and packing integrated tool, and opening a water hole channel and an injection hole of the nth stage hydraulic injection sand adding and packing integrated tool;

s7, carrying out hydraulic sand blasting perforation of the nth layer;

s8, throwing a ball to open the sand outlet of the inner sliding sleeve of the nth-stage sliding sleeve packer and the nth-stage hydraulic jetting sand adding and sealing integrated tool;

s9, carrying out nth layer fracturing construction by using the double-seal single card;

s10, carrying out steps S6-S9 through each layer of immobile pipe column combination units of the multilayer immobile pipe column combination units, and carrying out multilayer fracturing construction;

s11, performing layer-by-layer open-flow on all the constructed layer sections.