A variable diameter casing assembly and an installation method thereof for use in geological drilling

Abstract

The present invention provides a variable diameter casing assembly and an installation method thereof for geological drilling. The casing assembly includes a spiral combined pipe segment compressed into a tubular structure under the action of an external force and an assembly tool, and the contact surface of the adjacent spiral rings of the combined pipe segment is provided with mutually matching mother-and-child splicing parts; the assembly tool includes an inner and outer cylinder and a reducer with an assembly slot inside; when installing, the combined pipe segment is sleeved on the inner cylinder, assembled together into the outer cylinder, and placed in the casing installation position, the outer cylinder is fixed, and the inner cylinder is rotated to push the reducer head outward through the reducing mechanism at the bottom thereof, and then the inner cylinder is fixed, the outer cylinder is rotated in the reverse direction, and the reducer head is reversely rotated upward, and the combined pipe segment is introduced into the assembly slot to assemble into a complete pipe body. In the present invention, it is possible to realize the diameter reduction assembly after the pipe body enters from a hole of equal diameter or small diameter, and can be used as a casing for drilling, which solves the problems of great construction difficulty and high risk in the graded lowering of the casing.

Description

Technical Field

[0001] The present invention belongs to the field of geological drilling, and in particular relates to a variable diameter casing assembly and an installation method thereof in a geological borehole. The casing assembly comprises a variable diameter pipe and an installation tool. The variable diameter pipe can be changed in diameter in different states by the installation tool, and can be used in a geological borehole for installation as a casing, is not limited by the diameter of the installation hole, can be normally lowered into the hole, and realizes a change in diameter in the hole. Background Art

[0002] With the development of technologies such as resource exploration, engineering survey, and deep-sea drilling, the requirements for drilling efficiency and drilling quality are becoming increasingly higher. Broken rock formations and some special formations (such as water-sensitive formations, collapsible formations, etc.) are often encountered in geological drilling. Such formations are very easy to collapse during drilling, resulting in rock cuttings that cannot be completely salvaged and inability to advance. When drilling a single hole with a depth of more than 800 meters, there will be more complex formations encountered during the drilling process. When the drill bit is performing gas drilling operations through mudstone, sandstone and mudstone contact surfaces, coal seams and other formations that are prone to collapse, the hole mouth or hole wall is prone to collapse. If the hole mouth or hole wall collapses, accidents such as drilling resistance, stuckness, and drill burial may occur, which not only brings safety problems and increases drilling costs, but also seriously affects the progress of exploration.

[0003] For the above-mentioned hole collapse problem caused by special strata, the drilling treatment methods are: 1. Prepare high-quality mud or use chemical slurry, hoping that the mud can protect the hole wall and stop the collapse phenomenon; for strata that are not seriously broken, this solution is effective. This method is the first treatment method used for this type of strata because of its convenient slurry configuration, fast speed, low cost and simple operation. However, for some serious hole collapse or hole collapse at deeper drilling locations, this method is not very effective. 2. Cementation and solidification method, that is, injecting cementing materials such as quick-drying cement and other cementing materials into the stratum in the hole, hoping that the cementing materials can cement the broken stratum and stop the collapse of the stratum; this solution is also one of the more effective methods that are often used, but the implementation cycle of this method is relatively long, and the general solidification time takes 3 to 7 days. Sometimes it does not achieve the desired effect and wastes time. 3. Casing isolation method. Casing isolation is the most direct and most effective method. Situations that cannot be solved by general methods can be solved by casing isolation method. However, in the existing casing isolation method, casing must be lowered in stages during drilling. Each time the casing is lowered, a smaller casing than the previous one is lowered, and it is re-lowered from the hole mouth. This means that the casing needs to be lowered carefully, and often faces the risk of changing the drilling plan, or the need to re-expand the hole to the formation. Although this method is the most effective, it is costly, difficult to implement, and has high risks, so it is generally not used. In particular, in holes with a single hole depth of more than 800 meters, it is often necessary to lower casing of different diameters multiple times, and the method of lowering the casing is more complicated and more risky. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a variable diameter casing assembly and an installation method thereof for use in geological drilling. The variable diameter casing assembly can realize the change of the diameter of the pipe body under different conditions, and can be used in geological drilling as a geological drilling casing. By using the installation method of the present invention, the pipe body can be lowered into the borehole from a small-diameter hole, and assembled and its diameter can be changed in the borehole. The pipe body can be installed from a small-diameter hole with a smaller diameter or an equal diameter to the pipe body, and the risks and difficulties existing in the graded lowering of the existing casing can be solved.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is a reducer casing assembly, the casing assembly includes a combined pipe segment and a pipe segment assembly tool, the combined pipe segment is a spiral pipe segment compressed into a tubular structure under the action of an external force, and the contact surfaces of adjacent spiral rings thereof are provided with mutually matching mother-and-child splicing pieces, and when the combined pipe segment is compressed to the point where two adjacent spiral rings are in close contact, the mother-and-child splicing pieces on the contact surfaces of adjacent spiral rings are spliced ​​and connected to form a whole; the pipe segment assembly tool includes an inner cylinder, an outer cylinder and a reducer, the inner cylinder is placed in the outer cylinder, and a combined pipe segment installation cavity is provided between the inner cylinder and the outer cylinder; the reducer is an arc-shaped structure, wherein One end is installed at the bottom of the outer cylinder through a hinge, and an assembly slot is provided in the reducer. The inlet and outlet of the assembly slot are respectively arranged at the two ends of the arc-shaped reducer, and the inlet is arranged at the end adjacent to the hinge, and corresponds to the lower end outlet of the combined pipe segment installation cavity; a reducing mechanism is provided at the lower part of the inner cylinder, and when the inner cylinder is rotated, the reducing mechanism pushes the reducing head outward to complete the diameter reduction process, and the inlet of the reducing head after the diameter reduction still corresponds to the lower end outlet of the combined pipe segment installation cavity; the combined pipe segment is installed in the pipe segment installation cavity, and after the reducing head is expanded outward and reduced in diameter, the outer cylinder is rotated in reverse to introduce the combined pipe segment into the assembly slot for combined assembly of the combined pipe segment.

[0006] A preferred technical solution of the present invention: the casing assembly also includes a guide piece, the shape of the guide piece is exactly the same as that of the combined pipe segment, and the guide piece is made of plastic material; the guide piece is installed in the reducer.

[0007] The preferred technical solution of the present invention is as follows: the combined pipe segment is made of cold-rolled steel plate, the end of the combined pipe segment inserted into the assembly slot is sharpened into a pointed end, the thickness of the pipe segment is equal to the width of the combined pipe segment installation cavity, a first rack is provided on the inner wall of the combined pipe segment, the first rack is distributed along the spiral pipe segment, a second rack matching the first rack is provided on the outer wall of the inner tube, and when the combined pipe segment is installed in the combined pipe segment installation cavity, the first rack on the inner wall of the combined pipe segment and the second rack on the outer wall of the inner tube are meshed with each other, and the inner tube is connected to the outer tube.

[0008] The preferred technical solution of the present invention is as follows: the mother-and-child splicing parts include blocks and slots which are respectively arranged on the contact surfaces of two adjacent spiral ring segments and match each other, and when the combined pipe segments are compressed, the blocks on the contact surfaces of adjacent spiral ring segments are correspondingly embedded in the slots, and after compression and splicing, the inner walls of all the spiral ring segments are on the same plane, and the outer walls are also on the same plane; the upper and lower end surfaces of each spiral ring of the spiral pipe segment are respectively provided with mother-and-child splicing parts, and the splicing parts on the upper and lower end surfaces are the same or match each other; when the splicing parts on the upper and lower end surfaces of a single spiral ring are the same, the two adjacent spiral rings are spiral rings with different cross-sections, and the splicing parts on the two adjacent spiral rings match each other.

[0009] The preferred technical solution of the present invention is as follows: the length of the inner tube is greater than that of the outer tube; the diameter reducing mechanism is an arc-shaped groove arranged at the bottom of the inner tube; the curvature of the diameter reducing head is the same as that of the outer tube, and is hingedly connected to the pin seat at the bottom of the outer tube through a pin, and can rotate outward along the pin;

[0010] When the reducer is not expanded, it is embedded in the arc groove, and the outer diameter of the arc formed is equal to or smaller than the outer diameter of the outer cylinder. During the rotation of the inner cylinder, the reducer rotates along the arc groove and is pushed outward when rotating the connecting part of the arc groove and the inner cylinder, and the diameter of the arc formed at its outlet end is larger than the outer diameter of the outer cylinder.

[0011] A further technical solution of the present invention is as follows: the inlet of the reducer is arranged at one end adjacent to the hinge part, the height of the assembly slot at the inlet is equal to the height of a single spiral ring piece of the combined pipe segment, the height of the assembly slot at the outlet is the total height of the two spiral ring pieces minus the height of the mother-and-child splicing pieces on the two spiral ring pieces, an splicing piece slot is provided at the bottom of the assembly slot at the outlet, and a guide piece slot is provided on the side of the assembly slot at the outlet that is higher than the assembly slot area at the inlet and adjacent to the inlet; the lower end of the guide piece is inserted into the assembly slot from the guide piece slot and fixed at the outlet of the assembly slot, and the upper end is rotated in the opposite direction for one circle and then inserted into the assembly slot from the outlet of the assembly slot and spliced ​​with the lower end of the guide piece fixed at the outlet; the mother-and-child splicing piece fixed below the guide piece at the outlet of the assembly slot is embedded in the splicing piece slot.

[0012] The present invention also provides a method for installing the above-mentioned variable diameter casing assembly in a geological drilling hole, which is characterized by the following specific steps:

[0013] (1) When encountering a formation that requires casing during geological drilling, pull out the drill pipe, lower the drill pipe with a reaming drill bit to the specified depth, and expand the formation that needs to be isolated. The diameter of the expanded hole is at least 20 mm larger than the outer diameter of the combined pipe segment. The expansion depth is based on penetrating the formation that needs to be isolated. After the hole is expanded to the desired depth, pull out the drill pipe;

[0014] (2) Select the combined segments of corresponding specifications according to the drilling hole diameter, and determine the length of the combined segments after assembly according to the thickness of the formation to be isolated, calculate the number of spiral rings of the combined segments required to form the combined casing, and determine the cutting length of the combined segments;

[0015] (3) Select an assembly tool of appropriate length according to the length of the combined pipe segment, and sleeve the combined pipe segment of matching length inside the outer wall of the inner tube; assemble the guide piece into the assembly slot of the reducer, rotate it one circle, assemble and fix the two ends of the guide piece at the exit of the assembly slot, and install the reducer to the bottom of the outer tube; then insert the inner tube with the combined pipe segment into the outer tube, assemble them, and the assembled inner tube and outer tube can rotate relative to each other;

[0016] (4) Lower the assembled assembly tool and the combined pipe segment into the specified depth of the borehole, fix the outer tube, rotate the inner tube clockwise, and push the reducer outward through the reducer mechanism at the bottom of the inner tube until the outlet end of the reducer is located outside the outer tube wall;

[0017] (5) After the reducer is expanded outward to the right position, the inner tube is fixed and the outer tube is rotated counterclockwise, which drives the reducer to rotate counterclockwise. The combined pipe segment mounted on the inner tube is fixed with the inner tube and moves upward during the rotation of the reducer. When it moves to the lower end of the combined pipe segment, the lower end of the combined pipe segment enters the assembly slot from the inlet of the hinge end of the reducer. The outer tube is continued to be rotated counterclockwise. The reducer continues to rotate counterclockwise and moves upward. The combined pipe segment in the assembly slot moves downward from the outlet of the reducer to the assembly slot during the upward movement of the reducer. The combined pipe segment that comes out first and the combined pipe segment that comes out later are automatically crimped together to assemble into a complete pipe body. The outer tube is rotated continuously until the combined pipe segment on the outer wall of the inner tube is assembled. The outer tube and the inner tube are automatically separated, and the assembly tool is pulled out to complete the installation of the sleeve to be isolated.

[0018] A preferred technical solution of the present invention is as follows: the outer diameter of the selected combined pipe segment in step (2) is 5 mm smaller than the borehole diameter; in step (4), the assembly tool and the combined pipe segment are lowered to a depth that exceeds the isolation stratum depth by at least 0.5 m or reaches the bottom of the expanded hole.

[0019] A preferred technical solution of the present invention is as follows: in the step (3), the outer diameter of the inner tube is equal to the inner diameter of the combined tube segment, and mutually matching racks are provided on the outer wall of the inner tube and the inner wall of the combined tube segment. When the combined tube segment is sleeved on the outer wall of the inner tube, the rack on the outer wall of the inner tube meshes with the rack on the inner wall of the combined tube segment. The inlet end of the reducer is installed at the bottom of the outer tube through a hinge, and an arc-shaped groove-shaped reducer mechanism is provided at the bottom of the inner tube. After the reducer is installed, it is embedded in the arc-shaped groove at the bottom of the inner tube, and when the inner tube is rotated, the reducer rotates along the arc-shaped groove and is pushed outward to reduce the diameter when the arc-shaped groove contacts the inner tube. When the guide piece is installed, its lower end is inserted from the inlet of the assembly slot, and the reducer is rotated in the opposite direction by one circle, so that the upper end and the lower end of the guide piece are clamped and fixed at the outlet.

[0020] A preferred technical solution of the present invention is as follows: in the step (5), after the assembly of the combined pipe segments is completed, the outer cylinder is rotated to observe whether it moves upward or the force of the rotating outer cylinder is used to determine whether the inner hole combined pipe segments are installed smoothly. When the combined pipe segments are completely assembled, the assembly tool is pulled out.

[0021] Beneficial effects of the present invention:

[0022] (1) The combined reducer in the present invention has a smaller diameter in a relaxed state and a larger diameter after being compressed and assembled, thereby realizing the change of the diameter of the pipe body under different states. The combined reducer can be applied to the casing isolation method of geological drilling as a drilling casing to solve the hole collapse problem caused by special strata; the combined pipe forms a complete pipe body after being assembled, which can well support and protect the hole wall;

[0023] (2) The combined assembly tool of the present invention comprises an inner tube, an outer tube and a reducing head. A reducing mechanism is provided at the bottom of the inner tube. The reducing head is installed at the bottom of the outer tube and can be controlled to change its diameter by the reducing mechanism. The pipe segments of the combined reducing tube are installed between the inner tube and the outer tube, and the bottom of the loose parts is fixed on the reducing head. The reducing head is controlled by the reducing mechanism to drive the pipe segments to change their diameters. The reducing method is simple, and after the diameter change, the outer tube is directly controlled to rotate in the opposite direction, while the inner tube is kept stationary, so that the pipe segments can be quickly assembled during the rotation process.

[0024] (3) The installation method of the present invention can insert the combined reducer into the borehole when the diameter is relatively small, and after it is lowered to the installation position, it can be reduced in diameter and assembled, thus realizing the process of reducing the diameter of the pipe body after entering from a hole of equal diameter or small diameter, and can solve the problem of high difficulty and high risk in the existing staged lowering of casing.

[0025] (4) The installation tool used in the present invention has a simple structure and can quickly assemble the pipe body, which can quickly and effectively handle easily collapsed formations and greatly improve the drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 , Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the reducer of the present invention in a state where it is not expanded outward;

[0028] Figure 4 This is a schematic diagram of the reducer of the present invention in an outwardly expanded state;

[0029] Figure 5 It is an overall longitudinal cross-sectional view of the reducer of the present invention when it is not expanded outward;

[0030] Figure 6 It is an overall longitudinal cross-sectional view of the reducer of the present invention when it is expanded outward;

[0031] Figure 7 It is a schematic diagram of the inner cylinder structure of the present invention;

[0032] Figure 8 It is a schematic diagram of the outer cylinder structure of the present invention;

[0033] Fig. 9 It is a schematic diagram of the structure of the combined pipe segment of the present invention in a relaxed state;

[0034] Fig.10 yes Fig. 9 Middle AA section;

[0035] Fig.11 It is a schematic diagram of the structure of the combined pipe segment of the present invention in a compressed state;

[0036] Fig.12 yes Fig.11 BB cross-section diagram;

[0037] Fig.13 It is a schematic diagram of the end of the combined pipe segment inserted into the reducer;

[0038] Fig.14 It is a schematic diagram of the structure in which the combined pipe segment is installed on the inner tube;

[0039] Fig.15 and Fig.16 It is a structural schematic diagram of the reducer;

[0040] Fig.17 It is a schematic diagram of the structure of the guide piece;

[0041] Figures 18 to 20 It is a schematic diagram of various angles of the guide piece being assembled to the reducer;

[0042] Fig.21 yes Fig. 20 Middle AA section;

[0043] Figure 22 to Figure 28are cross-sectional views of different spiral rings;

[0044] Fig.29 There are two cross sections Fig. 22 Schematic diagram of the helical ring splicing;

[0045] Fig.30 There are two cross sections Fig.23 Schematic diagram of the helical ring splicing;

[0046] Fig.31 There are two cross sections Fig.24 Schematic diagram of the helical ring splicing;

[0047] Fig.32 The cross section is Fig.25 The spiral ring and cross section are Fig.26 Schematic diagram of the helical ring splicing;

[0048] Fig.33 The cross section is Fig. 27 The spiral ring and cross section are Fig.28 Schematic diagram of the spiral ring splicing.

[0049] In the figure: 1—inner tube, 100—second rack, 2—outer tube, 3—reducing head, 4—combined segment installation cavity, 5—assembly slot, 500—inlet, 501—outlet, 502—joining piece slot, 503—guide piece slot, 6—reducing mechanism, 7—combined segment, 700—first rack, 701—spiral ring, 8—hinge, 800—latch pin, 801—latch pin seat, 9—guide piece, 10—mother-child splicing, 1000—block, 1001—slot. DETAILED DESCRIPTION

[0050] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Figures 1 to 33 The accompanying drawings of the embodiments are drawn in a simplified manner and are only used to clearly and concisely illustrate the embodiments of the present invention. The technical solutions shown in the following drawings are specific solutions of the embodiments of the present invention and are not intended to limit the scope of the invention claimed for protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the utility model product is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0052] The embodiment provides a reducer casing assembly, the casing assembly comprising a combined pipe segment 7, a pipe segment assembly tool and a guide piece 9. Figures 9 to 12 As shown, the combined pipe segment 7 is a spiral pipe segment compressed into a tubular structure under the action of external force, and the contact surfaces of adjacent spiral rings 700 are provided with mutually matching mother-and-child splicing pieces 10, and when the combined pipe segment 7 is compressed to the point where the two adjacent spiral rings are in close contact, the mother-and-child splicing pieces 10 on the contact surfaces of the adjacent spiral rings are spliced ​​and connected as a whole. The combined pipe segment 7 is made of cold-rolled steel plate; the mother-and-child splicing piece 10 includes a clamping block 1000 and a clamping groove 1001, which are respectively arranged on the contact surfaces of two adjacent spiral ring segments 701 and match each other; a first rack 700 is provided on the inner wall of the combined pipe segment 7, and the first rack 700 is distributed in a spiral shape along the spiral pipe segment, and when the combined pipe segment 7 is compressed, as shown Fig.11 and Fig.12 As shown, the blocks 1000 of the contact surfaces of adjacent spiral ring pieces 701 are correspondingly embedded in the slots 1001, and after compression and splicing, the inner walls of all the spiral ring pieces 701 are on the same plane, and the outer walls are also on the same plane. Fig.13 As shown, the end of the combined pipe segment 7 inserted into the assembly slot 5 is cut into a pointed end.

[0053] The embodiment provides a reducer casing assembly, wherein the segment assembly tool is as follows: Figures 1 to 6 As shown, it includes an inner tube 1, an outer tube 2 and a reducer 3. The inner tube 1 is placed inside the outer tube 2. The length of the inner tube 1 is greater than that of the outer tube 2. A combined segment installation cavity 4 is provided between the inner tube 1 and the outer tube 2. The width of the combined segment installation cavity 4 is the same as the thickness of the combined segment 7. When the combined segment 7 is installed in the combined segment installation cavity 4, the inner tube 1 is connected to the outer tube 2. When the combined segment 7 is installed, as shown in FIG. Fig.14 As shown, the combined tube segment 7 is sleeved on the outer wall of the inner tube 1, and then embedded into the outer tube 2 together. Figure 7As shown, an arc-shaped groove-shaped diameter reducing mechanism 6 is provided at the bottom, and a second rack 100 matching the first rack 700 on the inner wall of the combined pipe segment 7 is provided on the outer wall of the inner tube 1. When the combined pipe segment 7 is installed on the inner tube 1, its second rack 100 is meshed with the first rack 700. As shown in FIG. 8, the outer tube 2 is provided with a latch seat 801 for installing a reducer 3 at the bottom, and the reducer 3 is also provided with latch holes matching each other. The reducer 3 is correspondingly inserted into the latch seat 801 and the latch holes on the reducer 3 through the latch 800, and the reducer 3 is hinged to the bottom of the outer tube 2. The reducer 3 can rotate along the latch 800 under the action of external force. The reducer 3 is an arc-shaped structure with the same curvature as that of the outer tube 2. When the diameter is not expanded, as shown in FIG. Figure 3 As shown, it is embedded in the arc groove. At this time, the outer diameter of the arc formed is equal to or smaller than the outer diameter of the outer cylinder 2; during the rotation of the inner cylinder 1, the reducer 3 rotates along the arc groove and is pushed outward to complete the diameter expansion process when the arc groove and the inner cylinder 1 are connected. Figure 4 As shown, the diameter of the arc formed by the outlet end of the diameter-changing mechanism is larger than the outer diameter of the outer cylinder 2 .

[0054] The embodiment provides a reducer sleeve assembly, wherein the guide piece 9 is as follows Fig.17 As shown, its shape is exactly the same as that of the combined pipe segment 7, which is equivalent to one of the spiral ring segments of the combined pipe segment 7. Its material is made of plastic material and is easy to deform. The guide piece 9 is pre-installed in the reducer 3 to play a role in forced positioning. The reducer 3 provided in the embodiment is as shown in FIG. Fig.15 and Fig.16 As shown, an assembly slot 5 is provided in the reducer 3, and the inlet 500 and outlet 501 of the assembly slot 5 are respectively arranged at the two ends of the arc reducer 3. The inlet 500 of the reducer 3 is arranged at the end adjacent to the hinge 8. The height of the assembly slot at the inlet is equal to the height of a single spiral ring piece 701 of the combined pipe segment 7, and the height of the assembly slot at the outlet is the total height of the two spiral ring pieces 701 minus the height of the mother-and-child splicing pieces 10 on the two spiral ring pieces 701. A splicing piece slot 502 is provided at the bottom of the assembly slot 5 at the outlet, and a guide piece slot 503 is provided at the side of the assembly slot at the outlet that is higher than the assembly slot area at the inlet near the inlet 500. The installation of the guide piece 9 is as shown in FIG. Figures 18 to 21As shown, the lower end of the guide piece 9 is inserted into the assembly slot 5 from the guide piece bayonet 503 and fixed at the outlet of the assembly slot 5, and the upper end is rotated in the opposite direction for one circle and then inserted into the assembly slot 5 from the outlet of the assembly slot 5 and is engaged with the lower end of the guide piece 9 fixed at the outlet; the mother-and-child assembly 10 fixed below the guide piece 9 at the outlet of the assembly slot 5 is embedded in the assembly piece bayonet 502. In actual installation, the guide piece 9 can also be inserted from the lower end from the inlet 500 of the assembly slot 5, and the reducer 3 is rotated in the opposite direction for one circle to just make the upper end of the guide piece 9 engage with the lower end, and then the inner tube 1, the combined pipe segment 7, the outer tube 2 and the reducer 3 with the guide piece 9 assembled are assembled, and the reducer 3 is expanded outward by rotating the inner tube 1, and then the outer tube is rotated in the opposite direction to drive the reducer 3 to rotate in the opposite direction, so that the lower end of the combined pipe segment 7 is introduced into the assembly slot 5, and assembled during the rotation process.

[0055] In the embodiment, the upper and lower end surfaces of each spiral ring segment 701 of the combined pipe segment 7 are respectively provided with a mother-and-child splicing piece 10, and the splicing pieces of the upper and lower end surfaces are identical or matched with each other; Figure 22 to Figure 24 The figure shows the matching of the parent-child splicing parts on the upper and lower end faces of the spiral ring piece 701, where Fig. 22 The spiral ring piece shown in the figure has an isosceles triangle block 1000 on its upper end surface and a matching slot 1001 on its lower end surface. The structure of the block 1000 and the slot 1001 is similar to that of Fig.23 Same, but in opposite directions, when splicing under pressure, such as Fig.29 As shown, the block 1000 on the upper end surface of each spiral ring is just embedded in the groove 1001 on the lower end surface of the adjacent spiral ring, and the inner surface and outer surface of the two adjacent spiral rings are respectively on the same plane.

[0056] Fig.23 and Fig.24 The spiral ring piece shown in the figure has a slot 1001 on its upper end surface and a matching block 1000 on its lower end surface. The block 1000 is arranged in an inverted isosceles triangle (such as Fig.23 shown) or an isosceles trapezoid ( Fig.24 As shown), the length of the card opening of the card slot 1001 is exactly the same as the bottom surface of the card block 1000, or is slightly smaller than the bottom surface thereof, so that the card block 1000 can be just inserted into the card slot 1001 under the action of pressure and will not fall off; Fig.23 The helical ring splicing in Fig.30 As shown, Fig.24 The helical ring splicing in Fig.31As shown, when the spiral rings are spliced ​​under pressure, the block 1000 on the lower end face of a spiral ring is just embedded in the slot 1001 on the upper end face of the adjacent spiral ring, and the inner surface and outer surface of the two adjacent spiral rings are respectively on the same plane. When the block 1000 is set to an isosceles trapezoid, in order to make it easier to insert, the notch of the slot 1001 can be set to the same inclined surface as the block.

[0057] Figure 25 to Figure 28 As shown, the upper and lower end surfaces of the spiral ring piece 701 have the same mother-and-child splicing pieces. In this case, two adjacent spiral ring pieces have different cross-sections, and the splicing pieces on the two adjacent spiral ring pieces 701 match each other. Fig.25 and Fig.26 The spiral rings match each other. Fig. 27 and Fig.28 The spiral ring pieces in the tube match each other; Fig.25 and Fig.26 The specific assembly diagram of the spiral ring is as follows: Fig.32 As shown, Fig. 27 and Fig.28 The specific assembly diagram of the spiral ring piece is as follows Fig.33 As shown, during the specific assembly, the spiral ring segments with blocks on both the upper and lower end faces and the spiral ring segments with grooves on both the upper and lower end faces are staggered. During the pressing process, the blocks 1000 on the upper and lower end faces of one spiral ring segment are correspondingly embedded in the grooves 1001 on the upper and lower two adjacent spiral ring segments. Since the adjacent spiral rings in the above situation have different cross-sections, the combined pipe segment of this structure cannot be made in one piece. Each spiral ring needs to be prepared separately and then assembled into an integral spiral pipe segment.

[0058] The installation steps of the present invention are further described below in conjunction with specific embodiments. In the following embodiments, the casing specification required for drilling is 90 mm; therefore, the combined pipe segment 7 is designed to have an inner diameter of 65 mm and an outer diameter of 85 mm in a normal relaxed state; the axial thread spacing is 30 mm; after the spiral pipe segment 1 is pressed and spliced, the inner diameter is 90 mm, the outer diameter is 110 mm, and the axial thread spacing is 13 mm. This solution can be installed into a casing with an inner diameter of 90 mm and an outer diameter of 110 mm by passing a part with an outer diameter of 85 mm through a 90 mm hole, and the pipe diameter is relatively enlarged by 25 mm. The size of its combined assembly tool matches the size of the combined pipe segment 7, and its design model size is a 65 mm to 90 mm reducer. The length of the inner tube 1 is slightly longer than that of the outer tube 2, and the inner tube and the outer tube form a relatively rotating body. The outer diameter of its reducer in the normal state is 85 mm. When in use, it is first lowered to the bottom of the hole, and the reducer can be screwed out by drilling the inner tube. The outer diameter after rotation and expansion is 120 mm. The letter splicing piece of the combined pipe segment 7 in the following embodiment adopts the structure shown in FIG. 23 , and the guide piece 9 has the same cross-sectional shape as the combined pipe segment 7 . The specific installation steps in the geological drilling hole are as follows:

[0059] (1) When encountering a formation that requires casing during geological drilling, the drill pipe is pulled out and the drill pipe with a reaming drill bit is re-inserted to the specified depth to expand the formation that needs to be isolated. The expanded hole diameter is required to be at least 20 mm larger than the outer diameter of the combined casing. The expansion depth is based on penetrating the formation that needs to be isolated. After the hole is expanded to the desired depth, the drill pipe is pulled out;

[0060] (2) Select the combined pipe segments of corresponding specifications according to the drilling hole diameter. The outer diameter of the selected combined pipe segments should be 5 mm smaller than the drilling hole diameter. Determine the length of the combined casing after assembly according to the required isolation formation thickness, calculate the number of turns of material required to form the combined casing, and then calculate the required length of the combined pipe segments. Select the material specifications as required and lay the corresponding amount of material.

[0061] (3) Install the combined pipe segment 7 to be lowered into the hole onto the inner tube 1 of the assembly tool for the above-mentioned reducer combined pipe, and the first rack 700 on the inner wall of the combined pipe segment 7 is meshed with the second rack 100 on the outer wall of the inner tube 1; assemble the guide piece 9 onto the reducer 3, install the reducer 3 onto the bottom of the outer tube 2, and then insert the inner tube 1 and the combined pipe segment 7 into the outer tube 2 together. At this time, the combined pipe segment 7 is placed in the annular installation cavity between the inner and outer tubes, and the outer tube 2 can rotate relatively;

[0062] (4) Use the drill pipe to lower the assembled assembly tool and the combined pipe segment 7 into the specified depth in the borehole, which is generally 0.5m beyond the depth of the formation to be isolated, or to the bottom of the expanded hole; fix the outer tube 2, rotate the inner tube 1 clockwise, and push the reducer 3 to the specified depth under the action of the reducer 6 at the bottom of the inner tube 1. Figure 4 As shown;

[0063] After the reducer 3 is expanded outwards to the right position, the inner cylinder 1 is fixed and the outer cylinder 2 is rotated counterclockwise, which drives the reducer 3 to rotate counterclockwise. Since the combined pipe segment 7 is fixed on the inner cylinder 1, the combined pipe segment 7, the outer cylinder 2 and the reducer 3 are relatively rotated. At this time, since the inner cylinder 1 is fixed and the outer cylinder 2 will drive the reducer 3 to rotate upward. When it moves to the lower end of the combined pipe segment 7, the lower end of the combined pipe segment 7 enters the assembly slot 5 from the inlet 500 of the hinge end of the reducer 3. The outer cylinder 1 is rotated counterclockwise and the reducer 3 is rotated upward. The combined pipe segment 7 moves downward from the outlet of the assembly slot 5. The combined pipe segment that comes out first is pressed together with the combined pipe segment that comes out later. The outer cylinder is rotated continuously and the bottom is assembled continuously until the combined pipe segments between the inner and outer cylinders of the assembly tool are used up and a complete sleeve is formed on the outside of the outer cylinder 2. The sleeve is just installed at the expansion position in step 1. At this time, the outer cylinder 2 and the inner cylinder 1 are automatically separated.

[0064] (6) After the combined casing is installed, the outer tube 2 can be rotated continuously to observe whether the outer tube 2 moves upward to judge whether the combined pipe segment in the hole is installed smoothly. It can also be roughly judged based on the force of rotating the outer tube. When the combined pipe segment is completely assembled, the assembly tool will automatically separate from the combined pipe segment and the assembly tool can be pulled out.

[0065] Since the combined casing in the present invention is mainly used for geological drilling, and the casing in the geological drilling mainly plays the role of isolating the strata, it is sufficient to use its skeleton support performance to prevent materials outside the pipe from entering the pipe, and there is no need to have any requirements for its waterproof performance. Therefore, the casing in the present invention can achieve the above-mentioned function of isolating the strata and supporting the pipe wall, and can be used in geological drilling. The present invention can completely overcome the problem of inconvenient casing installation in the previous casing isolation method.

[0066] In summary, the above is an embodiment of the present invention, but the present invention is not limited to the above embodiment. As long as the technical effect of the present invention is achieved by any same or similar means, it should fall within the scope of protection of the present invention.

Claims

1. A reducing sleeve assembly, characterized in that: The casing assembly comprises a combined pipe segment (7) and a pipe segment assembly tool. The combined pipe segment (7) is a spiral pipe segment compressed into a tubular structure under the action of an external force. The contact surfaces of adjacent spiral ring segments (701) are provided with mutually matching mother-and-child splicing pieces (10). When the combined pipe segment (7) is compressed until two adjacent spiral ring segments (701) are in close contact, the mother-and-child splicing pieces (10) on the contact surfaces of adjacent spiral ring segments (701) are spliced ​​and connected to form a whole. The pipe segment assembly tool comprises an inner tube (1), an outer tube (2) and a reducer (3). The inner tube (1) is placed in the outer tube (2), and a combined pipe segment installation cavity (4) is provided between the inner tube (1) and the outer tube (2). The reducer (3) is an arc-shaped structure, one end of which is installed at the bottom of the outer tube (2) through a hinge (8). ) is provided with an assembly slot (5), the inlet (500) and the outlet (501) of the assembly slot (5) are respectively arranged at two ends of the arc-shaped reducer (3), and the inlet (500) is arranged at one end adjacent to the hinge (8) and corresponds to the lower outlet of the combined pipe segment installation cavity (4); a reducing mechanism (6) is provided at the lower part of the inner cylinder (1), and when the inner cylinder (1) is rotated, the reducing mechanism (6) pushes the reducing head (3) outward to complete the reducing process, and the inlet (500) of the reducing head (3) after the reducing process still corresponds to the lower outlet of the combined pipe segment installation cavity (4); the combined pipe segment (7) is installed in the pipe segment installation cavity (4), and after the reducing head (3) is expanded outward and reduced in diameter, the outer cylinder (2) is rotated in the reverse direction to introduce the combined pipe segment (7) into the assembly slot (5) for combined assembly of the combined pipe segment (7); The combined pipe segment (7) is made of cold-rolled steel plate. The end of the combined pipe segment (7) inserted into the assembly slot (5) is sharpened into a pointed end. The thickness of the pipe segment is equal to the width of the combined pipe segment installation cavity (4). A first rack (700) is provided on the inner wall of the combined pipe segment (7). The first rack (700) is distributed along the spiral pipe segment. A second rack (100) matching the first rack (700) is provided on the outer wall of the inner tube (1). When the combined pipe segment (7) is installed in the combined pipe segment installation cavity (4), the first rack (700) on the inner wall of the combined pipe segment (7) and the second rack (100) on the outer wall of the inner tube (1) are meshed with each other, thereby connecting the inner tube (1) with the outer tube (2). The length of the inner cylinder (1) is greater than that of the outer cylinder (2); the reducing mechanism (6) is an arc-shaped groove arranged at the bottom of the inner cylinder (1); the reducing head (3) has the same arc as that of the outer cylinder (2), is hingedly connected to a latch seat (801) at the bottom of the outer cylinder (2) via a latch (800), and can rotate outward along the latch (800); when the reducing head (3) is not expanded, it is embedded in the arc-shaped groove, and the outer diameter of the arc formed is equal to or smaller than the outer diameter of the outer cylinder (2); during the rotation of the inner cylinder (1), the reducing head (3) rotates along the arc-shaped groove, and is pushed outward when the arc-shaped groove is rotated to the connection portion with the inner cylinder (1), and the diameter of the arc formed at its outlet end is greater than the outer diameter of the outer cylinder (2).

2. A reducing sleeve assembly according to claim 1, characterized in that: The sleeve assembly further comprises a guide piece (9), the shape of the guide piece (9) being completely identical to that of the combined pipe piece (7) and being made of a plastic material; the guide piece (9) is installed in the reducer (3).

3. A reducing sleeve assembly according to claim 1 or 2, characterized in that: The mother-and-child splicing piece (10) comprises a clamping block (1000) and a clamping groove (1001) respectively arranged on the contact surfaces of two adjacent spiral ring pieces (701) and matching each other, and when the combined pipe segment (7) is in a compressed state, the clamping blocks (1000) on the contact surfaces of adjacent spiral ring pieces (701) are correspondingly embedded in the clamping groove (1001), and after compression and splicing, the inner walls of all the spiral ring pieces (701) are on the same plane, and the outer walls are also on the same plane; the upper and lower end surfaces of each spiral ring piece (701) of the spiral pipe segment are respectively provided with a mother-and-child splicing piece (10), and the splicing pieces on the upper and lower end surfaces are the same or matching each other; when the splicing pieces on the upper and lower end surfaces of a single spiral ring piece (701) are the same, the two adjacent spiral ring pieces (701) are spiral rings with different cross-sections, and the splicing pieces on the two adjacent spiral ring pieces (701) match each other.

4. A reducing sleeve assembly according to claim 2, characterized in that: The inlet (500) of the reducer (3) is arranged at one end adjacent to the hinge member (8); the height of the assembly slot at the inlet portion is equal to the height of a single spiral ring piece (701) of the combined pipe segment (7); the height of the assembly slot at the outlet portion is the total height of the two spiral ring pieces (701) minus the height of the mother-and-child assembly pieces (10) on the two spiral ring pieces (701); a assembly piece slot (502) is provided at the bottom of the assembly slot (5) at the outlet portion, and the assembly slot at the outlet portion is higher than the assembly slot at the inlet portion. A guide piece snap-in opening (503) is provided on one side of the region adjacent to the inlet (500); the lower end of the guide piece (9) is inserted into the assembly slot (5) from the guide piece snap-in opening (503) and fixed at the outlet of the assembly slot (5); the upper end rotates in the opposite direction once and is inserted into the assembly slot (5) from the outlet of the assembly slot (5) and snap-connected with the lower end of the guide piece (9) fixed at the outlet; and the mother-and-child assembly piece (10) fixed below the guide piece (9) at the outlet of the assembly slot (5) is embedded in the assembly piece snap-in opening (502).

5. A method for installing the reducer sleeve assembly in claim 2 in a geological borehole, characterized in that The specific steps are as follows: (1) When encountering a formation that requires casing during geological drilling, pull out the drill pipe, lower the drill pipe with a reaming drill bit to the specified depth, and expand the formation that needs to be isolated. The diameter of the expanded hole is at least 20 mm larger than the outer diameter of the combined pipe segment. The expansion depth is based on penetrating the formation that needs to be isolated. After the hole is expanded to the desired depth, pull out the drill pipe; (2) Select the combined segments of corresponding specifications according to the drilling hole diameter, and determine the length of the combined segments after assembly according to the thickness of the formation to be isolated, calculate the number of spiral rings of the combined segments required to form the combined casing, and determine the cutting length of the combined segments; (3) Select an assembly tool of appropriate length according to the length of the combined pipe segment, and sleeve the combined pipe segment of matching length inside the outer wall of the inner tube; assemble the guide piece into the assembly slot of the reducer, rotate it one circle, assemble and fix the two ends of the guide piece at the exit of the assembly slot, and install the reducer to the bottom of the outer tube; then insert the inner tube with the combined pipe segment into the outer tube, assemble them, and the assembled inner tube and outer tube can rotate relative to each other; (4) Lower the assembled assembly tool and the combined pipe segment into the specified depth of the borehole, fix the outer tube, rotate the inner tube clockwise, and push the reducer outward through the reducer mechanism at the bottom of the inner tube until the outlet end of the reducer is located outside the outer tube wall; (5) After the reducer is expanded outward to the right position, the inner tube is fixed and the outer tube is rotated counterclockwise, which drives the reducer to rotate counterclockwise. The combined pipe segment mounted on the inner tube is fixed with the inner tube and moves upward during the rotation of the reducer. When it moves to the lower end of the combined pipe segment, the lower end of the combined pipe segment enters the assembly slot from the inlet of the hinge end of the reducer. The outer tube is continued to be rotated counterclockwise. The reducer continues to rotate counterclockwise and moves upward. The combined pipe segment in the assembly slot moves downward from the outlet of the reducer to the assembly slot during the upward movement of the reducer. The combined pipe segment that comes out first and the combined pipe segment that comes out later are automatically crimped together to assemble into a complete pipe body. The outer tube is rotated continuously until the combined pipe segment on the outer wall of the inner tube is assembled. The outer tube and the inner tube are automatically separated, and the assembly tool is pulled out to complete the installation of the sleeve to be isolated.

6. The installation method of a reducer sleeve assembly in a geological drilling hole according to claim 5, characterized in that: The outer diameter of the combined pipe segment selected in step (2) is 5 mm smaller than the borehole diameter; in step (4), the assembly tool and the combined pipe segment are lowered to a depth that exceeds the isolation stratum depth by at least 0.5 m or reaches the bottom of the expanded hole.

7. The installation method of a reducer sleeve assembly in a geological drilling hole according to claim 5, characterized in that: In the step (3), the outer diameter of the inner tube is equal to the inner diameter of the combined tube segment, and matching racks are provided on the outer wall of the inner tube and the inner wall of the combined tube segment. When the combined tube segment is sleeved on the outer wall of the inner tube, the rack on the outer wall of the inner tube meshes with the rack on the inner wall of the combined tube segment. The inlet end of the reducer is installed at the bottom of the outer tube through a hinge, and the bottom of the inner tube is provided with an arc-shaped groove-shaped reducer mechanism. After the reducer is installed, it is embedded in the arc-shaped groove at the bottom of the inner tube, and when the inner tube is rotated, the reducer rotates along the arc-shaped groove and is pushed outward to reduce the diameter when the arc-shaped groove contacts the inner tube. When the guide piece is installed, its lower end is inserted from the inlet of the assembly slot, and the reducer is rotated in the opposite direction for one circle, so that the upper end and the lower end of the guide piece are clamped and fixed at the outlet.

8. The installation method of a reducer sleeve assembly in a geological drilling hole according to claim 5, characterized in that: In the step (5), after the assembly of the combined pipe segments is completed, the outer cylinder is rotated to observe whether it moves upward or the force of rotating the outer cylinder is used to judge whether the inner hole combined pipe segments are installed smoothly. When the combined pipe segments are completely assembled, the assembly tool is pulled out.

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