Packing type grading cementing device

Abstract

The invention discloses a packing type graded cementing device, which relates to the technical field of oil exploitation, and comprises a closed sleeve piece, a floating foot, a centering and righting assembly, a separation assembly, a sleeve outer packing piece and an operation rubber plug mechanism. The closed casing pipe part comprises a plurality of casing pipes, floating feet are arranged at the lower end of the closed casing pipe part, centering and righting assemblies are arranged outside the casing pipes, separation assemblies are arranged among the casing pipes, casing pipe outer packing parts are arranged outside the casing pipes, and operation rubber plug mechanisms are arranged inside the casing pipes. The mounting rings at the two ends of the centering and righting assembly are fixed to the exterior of the sleeve, displacement, caused by elastic deformation, between the two mounting rings is counteracted through telescopic movement of a telescopic plate in the centering and righting assembly and the interior of the square sleeve, and it is guaranteed that the centering and righting assembly is located at the position outside the sleeve; the stability of the centralizer in the casing and the fixity of the position of the centralizer are improved, and after the interior of an oil well is detected, the centralizer is installed on the casing in advance, so that a greater effect can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploitation, in particular to a sealed-type graded cementing device. Background Art

[0002] With the increasing frequency of oil exploration and production activities, drilling technology is constantly developing. Effective cementing measures are needed before drilling into the oil layer. The continuous increase in drilling depth and the frequent occurrence of complex geological conditions have put forward higher requirements for cementing technology. Its purpose is to ensure that the annular space between the casing and the well wall is effectively sealed, thereby isolating different formation fluids (such as oil, gas, and water) and providing stable structural support for subsequent production activities. By forming a circular cement sealing ring on the well wall by injection, the corrosion effect of oil, gas, etc. (such as hydrogen sulfide) inside the soil layer on the casing is reduced.

[0003] However, when the current staged cementing device lowers the sealing casing by means of an elastic or rigid stabilizer installed on the outside, the casing is kept centered by the stabilizer. When cementing oil wells at greater depths, it is often necessary to stabilize the closed sleeve by means of an elastic stabilizer. The existing elastic stabilizer adopts a spring-type stabilizer. When the stabilizer penetrates deep into the oil well, the deformation of the spring will cause the circular rings at both ends of the stabilizer to expand and contract outside the casing. The movement between the casing and the circular rings at both ends of the stabilizer will cause the position of the stabilizer to change, which can easily change the position of the stabilizer outside the casing, affecting the centering of the casing and the grouting of cement slurry in the cementing operation.

[0004] In the existing technology, there is a lack of equipment and technology that can well solve the above problems. Summary of the invention

[0005] The invention provides a sealed-type graded cementing device, which is used to solve the defect in the prior art that an elastic centralizer of a cementing device placed in a deep well section is easy to move and dislocate.

[0006] The present invention provides a sealed graded cementing device, comprising: a closed casing component, which is composed of a plurality of casings uniformly distributed along the axial direction, with gaps between the casings, and connected by a connecting sleeve, the outer side wall of the connecting sleeve is provided with a plurality of uniformly distributed flow guide holes, and the outer side of the casing is provided with uniformly distributed limit clamps; a floating foot, which is arranged at the outer bottom end of the closed casing component, a one-way valve mechanism is arranged inside the floating foot, and a floating hoop is arranged on the lower side of the outer side of the closed casing component; a centering straightening component, which is arranged on each casing, and the centering straightening component is located between two limit clamps of the same casing; a partition component, which is arranged at the gap between the casings; a casing outer sealing component, which is arranged outside the casing; an operating plug mechanism, which is arranged inside the casing.

[0007] Optionally, the one-way valve mechanism includes a ball seat arranged inside the floating foot, the center of the ball seat is a circular hole connected up and down, the upper edge of the ball seat is provided with a plurality of flow bottom holes distributed around the central circular hole, the upper end of the ball seat is provided with a valve ball used to cooperate with the circular hole at the center, the upper end of the floating foot is a closing end used to cooperate with the valve ball, the interior of the floating foot and the interior of the sleeve are through-connected, and the valve ball can move up and down between the ball seat and the closing end.

[0008] Optionally, the centering and straightening assembly includes a mounting ring, which is arranged between two limit clamps on the same sleeve, and the sides of the mounting rings that are close to each other are hinged with a plurality of evenly distributed square sleeves, and telescopic plates are inserted inside the square sleeves, and the other ends of the telescopic plates inserted inside the square sleeves are hinged to each other, and rollers are arranged at the hinges between the telescopic plates through bearings; two insertion rods are fixedly connected to the sides of the square sleeves that are away from each other, and two evenly distributed connecting holes are provided at one end of the telescopic plate inserted into the square sleeve, and the insertion rods are inserted into the connecting holes, and the outsides of the insertion rods are sleeved with extrusion springs used in conjunction with the telescopic plates.

[0009] Optionally, the rod ends of the insertion rod away from the square sleeve are fixedly connected with anti-drop blocks, and the ends of the connecting holes away from the rollers are embedded with limit stop rings used in conjunction with the anti-drop blocks.

[0010] Optionally, the partition assembly includes a plurality of movable rings arranged in the gaps between the sleeves, the movable rings can move up and down in the gaps between the sleeves, and positioning retaining rings are arranged inside the movable rings, and the inner diameter of the positioning retaining rings gradually decreases from top to bottom; a plurality of evenly distributed limiting holes are opened at the upper end of the outer side of the movable rings, and a plurality of evenly distributed guide rods are fixedly connected to the lower end of the inner side of the gaps between the sleeves, the guide rods are adapted to the inner side of the limiting holes, and the outer side of the guide rods are sleeved with control springs used in conjunction with the movable rings, and the control springs are located on the lower side of the outer side of the movable rings.

[0011] Optionally, the casing outer sealing member includes a plurality of pressurized expansion rings evenly distributed on the casing, and a first water passage cavity, a second water passage cavity and a third water passage cavity are respectively opened on one side of the interior of the pressurized expansion ring from bottom to top, the interior of the first water passage cavity is through-connected with the interior of the casing, an end of the second water passage cavity close to the casing is through-connected with the middle of the first water passage cavity, the middle of the second water passage cavity is through-connected with the middle of the third water passage cavity, and the middle of the third water passage cavity is through-connected with the bottom end of the interior of the pressurized expansion ring; a first rebound valve is arranged inside the first water passage cavity, a second rebound valve is arranged inside the second water passage cavity, and a horizontally movable closing valve is arranged inside the third water passage cavity, a reflux tube cavity is opened on the side of the inner wall of the pressurized expansion ring close to the water passage cavity, and the upper end of the interior of the pressurized expansion ring and the side of the interior of the third water passage cavity close to the casing are through-connected via the reflux tube cavity.

[0012] Optionally, the first rebound valve can control the opening and closing of the connection between the first water channel and the second water channel, the second rebound valve can control the opening and closing of the connection between the second water channel and the third water channel, and the closing valve can control the opening and closing of the connection between the third water channel and the pressurized expansion ring and the connection between the third water channel and the second water channel.

[0013] Optionally, the operating rubber plug mechanism includes a plurality of opening rubber plugs and closing rubber plugs, the tail end of the closing rubber plug is made of a rigid material, and the radius of the tail end of the closing rubber plug gradually decreases from top to bottom.

[0014] Optionally, the base radius of the open rubber plug tail end is smaller than the inner diameter of all the positioning retaining rings, and the closed rubber plug tail end is matched with the positioning retaining rings.

[0015] Optionally, a sealing bushing is provided on the inner wall of the connecting sleeve to cooperate with the gap between the sleeves, and when the movable collar moves to the bottom at the gap between the sleeves, the guide hole is not blocked by the movable collar.

[0016] The present invention provides an isolation type staged cementing device, which is fixed by mounting rings at both ends of a centering straightening assembly and the outside of a casing, and the displacement between the two mounting rings caused by elastic deformation is offset by the telescopic movement of a telescopic plate in the centering straightening assembly and the inside of a square casing, thereby ensuring that the centering straightening assembly is located outside the casing, increasing the stability of the straightener on the casing and the fixity of its position, and after detecting the inside of an oil well, the straightener pre-installed on the casing can play a greater role. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the present invention; Figure 2 It is a partial structural stereoscopic schematic diagram of the present invention; Figure 3 The present invention Figure 2 The enlarged view of point A in the middle; Figure 4 This is a three-dimensional enlarged schematic diagram of the connecting sleeve of the present invention. Figure 1 ; Figure 5 This is a three-dimensional enlarged schematic diagram of the connecting sleeve of the present invention. Figure 2 ; Figure 6 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 2 ; Figure 8 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 3 ; Fig. 9 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 4 ; Fig.10 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 5 ; Fig.11 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 6 ; Fig.12 This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 7 ; Fig.13This is a schematic diagram of the stage state of the graded cement slurry injection of the present invention. Figure 8 ; Fig.14 It is a schematic diagram of the casing outer packing member of the present invention in a non-circulating state; Fig.15 It is a schematic diagram of the state of the casing outer packing member in circulation of the present invention; Fig.16 It is a schematic diagram of the state of the casing outer packing after circulation of the present invention; Fig.17 It is a schematic diagram of the three-dimensional structure of the centering and righting assembly of the present invention; Fig.18 It is a schematic diagram of the internal structure of the centering and righting assembly of the present invention; Fig.19 It is a schematic diagram of the three-dimensional structure of the partition component of the present invention.

[0019] Reference numerals: 1. Closed casing parts; 2. Floating feet; 3. Centering and straightening components; 301. Mounting ring; 302. Square casing; 303. Telescopic plate; 304. Roller; 305. Insertion rod; 306. Connection hole; 307. Extrusion spring; 308. Anti-drop block; 309. Limiting retaining ring; 4. Separation components; 401. Movable sleeve ring; 402. Positioning retaining ring; 403. Limiting hole; 404. Guide rod; 405. Control spring; 5. Casing outer packing; 501. Pressurized expansion ring; 502. The first water passage cavity; 503, the second water passage cavity; 504, the third water passage cavity; 505, the first rebound valve; 506, the second rebound valve; 507, the closing valve; 508, the reflux cavity; 6, the operating plug mechanism; 601, the opening plug; 602, the closing plug; 7, the sleeve; 8, the connecting sleeve; 9, the guide hole; 10, the limiting clamp ring; 11, the one-way valve mechanism; 1101, the ball seat; 1102, the flow bottom hole; 1103, the valve ball; 12, the floating hoop; 13, the sealing bushing. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0021] As mentioned above, when the current staged cementing device lowers the sealing casing by means of an elastic or rigid stabilizer installed externally, the centering of the casing is maintained by the stabilizer. When cementing oil wells at greater depths, it is often necessary to stabilize the closed sleeve by means of an elastic stabilizer. The existing elastic stabilizer adopts a spring-type stabilizer. When penetrating into the interior of the oil well, the deformation of the spring will cause the circular rings at both ends of the stabilizer to expand and contract outside the casing. Due to the movement between the casing and the circular rings at both ends of the stabilizer, the position of the stabilizer will change, which can easily change the position of the stabilizer outside the casing, affecting the centering of the casing and the grouting operation of the cement slurry in the cementing operation.

[0022] To address this problem, the present invention provides an isolation-type staged cementing device, which can connect a slurry centralizer to the outside of the casing in the form of fixing the two ends of the centralizer to the outside of the casing, and use the elasticity and telescopic properties of the centralizer itself to offset the relative displacement of the two ends of the centralizer caused by deformation.

[0023] Combine the following Figure 1 to Figure 19 The present invention is described in detail.

[0024] First embodiment: like Figure 1~Figure 3As shown, in this embodiment, the isolation type graded cementing device includes a closed casing member 1, which includes a plurality of casings 7 evenly distributed along the axial direction (three are used as an example in this application), and there is a gap between every two adjacent casings 7, and a connecting sleeve 8 is provided between the two adjacent casings 7, and a cylindrical sealing bushing 13 is fixedly connected to the inner wall of each connecting sleeve 8 for sealing, and a plurality of evenly distributed guide holes 9 are provided on the outer wall of the connecting sleeve 8, so that the interior of the connected closed casing members 1 can be connected with the oil well, and after the closed casing member 1 is deeply inserted into the interior of the oil well, an annulus is formed between the closed casing member 1 and the oil well, and cement grouting work is performed inside the annulus, and a movable collar 401 is provided inside the gap between each casing 7. , the height of the movable ring 401 is less than the height of the gap between the sleeves 7, and the movable ring 401 can move up and down inside the gap between the sleeves 7. A number of evenly distributed limiting holes 403 are evenly distributed along the circular ring at the outer upper end of the movable ring 401, and a number of evenly distributed guide rods 404 are also fixedly connected along the circular ring at the inner lower end of the gap between each sleeve 7. Each guide rod 404 is inserted into the corresponding limiting hole 403 opened on the movable ring 401 to prevent the movable ring 401 from rotating, and a control spring 405 is sleeved on each guide rod 404, and the control spring 405 is located on the outer lower side of the movable ring 401. In the absence of a certain external force, the control spring 405 pushes the movable ring 401 upward, which can block the guide hole 9 opened on the connecting sleeve 8, thereby completing the closure of the internal space of the sleeve 7.

[0025] A positioning retaining ring 402 is arranged inside each movable ring 401. Fig.19 As shown, there is an inward protrusion at an upper position, and starting from the protrusion position, it is connected with the inner bottom end of the movable ring 401 in the form of an inclined surface downward, and a complete separation component 4 is composed of the movable ring 401, the positioning retaining ring 402, the limiting hole 403, the guide rod 404 and the control spring 405. Two limiting clamps 10 are arranged on the outside of each sleeve 7, and the two limiting clamps 10 are fixed on the outer wall of the corresponding sleeve 7. A centering straightening component 3 is arranged between the two limiting clamps 10 on the outside of the same sleeve 7 on the outside of each sleeve 7. The centering straightening component 3 is mainly composed of two upper and lower distributed mounting rings 301, square sleeves 302 evenly distributed along the two mounting rings 301, a telescopic plate 303 inserted in the inside of the square sleeve 302, and rollers 304 arranged at the hinge after the upper and lower telescopic plates 303 extend to the outside of the square sleeve 302.

[0026] like Fig.17 and Fig.18 As shown, the upper and lower mounting rings 301 are arranged on the side where the two limiting clamps 10 outside the same casing 7 are close to each other, and the two mounting rings 301 are fixedly connected to the limiting clamps 10. A number of evenly distributed square casings 302 are hinged on the side where the two mounting rings 301 are close to each other. Two plug rods 305 are fixedly connected to one end of the interior of each square casing 302 close to the hinge of the mounting ring 301. A telescopic plate 303 is inserted into the interior of each square casing 302. The telescopic plates 303 arranged inside the two square casings 302 are opposite to each other, and the other ends of the two opposite telescopic plates 303 inserted into the square casing 302 are hinged to each other. The rollers 304 arranged at the hinges of the two opposite telescopic plates 303 are used to reduce the friction between the centering straightening assembly 3 and the inner wall of the oil well when the cement injector is lowered.

[0027] When the cementing device is lowered, the inner wall of the oil well is uneven and will contact the roller 304 of the centering straightening assembly 3, causing the roller 304 to be squeezed. The roller 304 squeezes the two telescopic plates 303, making the angle formed between the two telescopic plates 303 larger. After the angle increases, the ends of the telescopic plates 303 that are hinged to each other need to move away from each other to offset the distance change caused by the change in the angle. Two connecting holes 306 are provided at one end of the interior for inserting the plug rod 305. Two extrusion springs 307 are provided at one end of the interior of the square sleeve 302 close to the hinged end of the mounting ring 301. The two springs are correspondingly sleeved on the two plug rods 305 to squeeze the two telescopic plates 303 toward the outside of the square sleeve 302. In order to prevent the roller 304 from losing the squeeze of the inner wall of the oil well, the roller 304 can move outward again to fit the inner wall of the oil well.

[0028] The two telescopic plates 303 can be moved and retracted into the square sleeve 302 when squeezed to offset the problem of misalignment of the centralizer caused by the two mounting rings 301 moving away from each other when the squeezing centering straightening assembly 3 is squeezed and approaching each other when reset. At the same time, the telescopic plates 303 are extended and retracted inside the square sleeve 302, and the square sleeve 302 is hingedly rotated on the mounting ring 301 to offset the roller 304 moving toward or away from the sleeve 7. The square sleeve 302 is hingedly rotated on the mounting ring 301 to offset the telescopic plates 303 due to the roller 304. 04, when the inner wall of the oil well does not squeeze the roller 304, the two squeezing springs 307 will squeeze the telescopic plate 303 out. In order to prevent the telescopic plate 303 from being squeezed out of the square sleeve 302, an anti-slip block 308 is fixedly connected to the end of each plug rod 305 away from the connection with the square sleeve 302, and a limit ring 309 is embedded in the inside of each connecting hole 306 close to the corresponding plug-in end of the square sleeve 302 to prevent the telescopic plate 303 from moving out of the square sleeve 302.

[0029] The spring force is based on Hooke's law and is: , (Formula 1), in, F is the restoring force exerted by the spring, in Newtons ( N ); k It is the spring coefficient or elastic coefficient, which reflects the ability of the spring to resist deformation. It is related to the material and the unit is Newton per meter ( N / m ); x is the displacement of the spring relative to the unstressed state, that is, the distance it is stretched or shortened, in meters ( m ).

[0030] When the cementing device is lowered, the telescopic plate 303 moves toward the inside of the square casing 302 when the roller 304 is squeezed by the inner wall of the oil well. The amount by which the telescopic plate 303 retracts toward the inside of the square casing 302 is the amount by which the squeezing spring 307 is compressed, which is x .

[0031] like Figure 6~Figure 13As shown, in the present embodiment, when the rubber plug is inserted into the interior of the casing 7, the rubber plug presses against the movable collar 401, and the rubber plug is pumped into the interior of the movable collar 401 under the pressure of pressurization and pumping. If the tail of the rubber plug does not get stuck in the interior of the positioning retaining ring 402 inside the movable collar 401, the rubber plug will continue to move downward until it contacts the bottom of the pipe. If the tail of the rubber plug gets stuck in the interior of the positioning retaining ring 402, in the process of continuing to pressurize downward, the rubber plug will squeeze the movable collar 401 downward through the positioning retaining ring 402 until the movable collar 401 does not block the guide hole 9 opened on the outer wall of the connecting sleeve 8, so that the next stage of cementing can be carried out.

[0032] Therefore, an operating plug mechanism 6 is provided inside the combined sleeve 7, and the operating plug mechanism 6 includes two types of plugs, an opening plug 601 and a closing plug 602, and there are a plurality of each of the two types of plugs (taking a combination of three sleeves as an example in this application, there are a total of four opening plugs 601 and two closing plugs 602), such as Figures 6 to 13 As shown, after the three sleeves are assembled, a floating foot 2 is installed at the outer lower end of the lowermost sleeve 7, and the inside of the floating foot 2 is a one-way valve mechanism 11, wherein the inner upper end of the floating foot 2 is a closing opening that is closed to the middle both up and down, and a ball seat 1101 is arranged inside the floating foot 2, and the middle of the ball seat 1101 is a circular through hole that is connected up and down, and a plurality of evenly distributed flow bottom holes 1102 are opened around the center at the outer upper end of the ball seat 1101, and a valve ball 1103 is arranged at the center of the upper end of the ball seat 1101. 1103 can block the hole at the center of the upper end of the ball seat 1101. When the valve ball 1103 moves upward, it can block the closing end of the upper end of the floating foot 2, so that the liquid or cement slurry inside the casing 7 can flow downward from the inside through the closing end of the floating foot 2 and flow through the inside of the flow bottom hole 1102 to the annulus between the casing 7 and the inner wall of the oil well. However, when the pressure of the liquid or cement slurry in the annulus is relatively high and there is a tendency to flow back into the casing 7, the valve ball 1103 can prevent the backflow by blocking the closing end upward, thereby ensuring the stability of the injected cement slurry.

[0033] from Figure 6~Figure 13 It can be seen that the operation process of cement slurry injection at each stage, first before lowering the cement injector, the height distance between the bottom of the floating foot 2 and the first guide hole 9 outside the connecting sleeve 8 from the bottom to the top is measured, which is recorded as , and then measure the distance between the two external guide holes 9 of the connecting sleeve 8 After the cementing device is placed, the distance from the second diversion hole 9 outside the connecting sleeve 8 from the bottom to the wellhead is After the cementing device is lowered into the oil well, the drilling fluid is first injected into the casing. When the drilling fluid is injected, the height of the drilling fluid entering the annulus after it flows out from the casing 7 is detected by the measuring instrument. When the height of the drilling fluid reaches the bottom diversion hole 9 and is close to it (the error is less than 20 cm), the volume of the injected drilling fluid is recorded and recorded as , the total volume inside the sleeve 7 is , then the volume of cement slurry injected in the first stage is , and then continue to inject drilling fluid. After the detection instrument, when the drilling fluid enters the inside of the annulus and is less than 20 cm below the top diversion hole 9, the volume of drilling fluid injected at this time is recorded as , then the volume of cement slurry to be injected in the second stage is The final volume of drilling fluid filled is , then the third section is the last section of cementing work in this example, and the volume of cement slurry to be injected is .

[0034] Before pouring cement slurry, it is necessary to inject drilling fluid, flush the mud cake inside the annulus, and then inject isolation fluid to separate the drilling fluid and cement slurry to prevent the cement slurry from being affected by the drilling fluid. At the same time, the isolation fluid can clean the mud cake on the well wall inside the annulus more cleanly. After injecting the isolation fluid, inject After the cement slurry is injected, an open rubber plug 601 is immediately pumped into the interior of the casing 7. After the open rubber plug is placed into the interior of the casing 7, a volume of not less than the volume of each individual casing 7 needs to be pumped into the casing. The isolation fluid is then inserted into a closing rubber plug 602 and pumped into The cement slurry is pumped in, and then an open rubber plug 601 is placed, and then the drilling fluid and the closing rubber plug 602 are pumped in repeatedly. The upper tail end of the open rubber plug 601 is made of soft material, and the radius is smaller than the inner diameter of the positioning retaining ring 402, so that the open rubber plug 601 can pass through the interior of the positioning retaining ring 402 and move downward, and can pass directly to the bottom end. The upper tail end of the closing rubber plug 602 is made of rigid material such as steel and other hard materials, and the inner diameter of the inner protrusion of the positioning retaining ring 402 is It gradually shrinks, so that the upper positioning retaining ring 402 will not jam the closing plug 602 that needs to be put down, and the order of placing the closing plug 602 is also to put the smaller tail radius first, so that it can pass through the interior of the positioning retaining ring 402 with a larger inner diameter at the upper end. The internal protrusion of the positioning retaining ring 402 is located at the top, and it is connected to the inner bottom of the positioning retaining ring 402 in the form of a slope. The outer edge of the plug can be squeezed and fit tightly against the inner wall of the sleeve 7 or the positioning retaining ring 402, which is convenient for pressurization operation.

[0035] In order to ensure that the casing can remain stable after each cementing section is completed, a casing outer packing 5 is provided on the outside of each casing 7. The casing outer packing 5 is located on the lower side of the central straightening assembly 3, and the casing outer packing 5 is composed of three water passages, three valves and a return pipe, wherein the casing outer packing 5 includes a pressurized expansion ring 501 sleeved on the outside of the casing 7, the outer part of the pressurized expansion ring 501 is made of deformable rubber material, and the inside is hollow, and three water passages are opened from bottom to top at the lower end of one side of the inner part of the pressurized expansion ring 501, which are respectively called the first water passage 502, the second water passage 503 and the third water passage 504 from bottom to top, as shown in FIG. Figures 14 to 16 As shown, one end of the first water channel 502 close to the sleeve 7 and the interior of the sleeve 7 are connected through a small hole channel, and the middle position of the first water channel 502 is connected to the end of the second water channel 503 close to the sleeve 7, the middle part of the second water channel 503 is connected to the inner middle section of the third water channel 504, the inner middle section of the third water channel 504 is connected to the bottom end of the hollow interior of the pressurized expansion ring 501, and the through channel of the third water channel 504 and the pressurized expansion ring 501 is on the same vertical line as the through channel of the second water channel 503 and the third water channel 504.

[0036] At the starting position, a first rebound valve 505 is arranged inside the first water passage 502, and a second rebound valve 506 is arranged inside the second water passage 503. Both rebound valves are spring-type rebound valves. The two rebound valves are respectively fixed at one end of the two water passages away from the sleeve 7. The two rebound valves are squeezed toward the sleeve 7 by a spring. The starting position of the first rebound valve 505 blocks the through passage inside the sleeve 7 and the first water passage 502, and blocks the connecting cavity between the first and second water passages. The starting position of the second rebound valve 506 blocks the through passage between the second and third water passages, but does not block the connecting point between the first and second water passages. In this way, when the isolation liquid or other expansion liquid enters from the first water passage 502, the first rebound valve 505 is pushed to flow into the second water passage 503, and the second rebound valve 506 is also moved away from the sleeve 7.

[0037] A closing valve 507 that can move laterally is arranged inside the third water passage 504. The closing valve 507 is composed of two cylindrical plugs and a thin rod in the middle. The initial position of the closing valve 507 is as follows: Fig.14 As shown, the thin rod in the middle is in the communication position between the second and third water passages, and will not block the flow of isolation liquid and other liquids from the second water passage 503 to the third water passage 504. The maximum distance that the closing valve 507 moves toward the sleeve 7 is as shown in FIG. Fig.14As shown, the communication between the return tube cavity 508 opened on the inner wall of the pressurized expansion ring 501 and the third water passage 504 will not be blocked, and the farthest movement in the direction away from the sleeve 7 is as shown in FIG. Fig.16 As shown, the connection between the third water passage 504 and the inside of the pressurized expansion ring 501 is not out of the closed state. Fig.14 This is the initial state, that is, the state when no isolation fluid is injected under pressure. Fig.15 It is the state during the pressurized injection process. Fig.16 After the pressurized injection is completed, the isolation liquid flows through the inside of the three cavities to the inside of the pressurized expansion ring 501, and when the inside of the pressurized expansion ring 501 is filled, since the return tube cavity 508 is very thin, the pressurized expansion ring 501 expands first, and when the liquid expanded to the inside flows through the inside of the return tube cavity 508 to the inside of the third water passage 504 due to the pressure, it will push the closing valve 507 to move away from the sleeve, and completely close the passage. The expanded pressurized expansion ring 501 squeezes the external cement slurry, and finally ensures the stability of the sleeve 7 at the corresponding position. The elastic force of the springs in the two rebound valves is calculated as shown in (Formula 1).

[0038] The present invention adopts the above-mentioned design to perform graded isolation grouting operation on the oil well by adding cement slurry, rubber plug and spacer fluid in stages, such as Figures 6 to 13 As shown in the figure, various states of the cement slurry injection process are shown. After the drilling fluid is injected and cleaned, the isolation fluid is injected into the casing 7. The isolation fluid injection needs to wait until the annulus is completely filled with the isolation fluid, and then the isolation fluid in the casing 7 is extracted by pumping. Then, no less than 10000 t / cm3 of the casing 7 is injected into the casing 7. Then, an open rubber plug 601 is added behind the cement slurry. After the rubber plug 601 is opened, the isolation liquid is added. The maximum expansion volume of the pressurized expansion ring 501 that can be filled with liquid is , the volume of the isolation fluid added is , and then add a closing rubber plug 602 and start pressurizing.

[0039] The spring forces of the two rebound valves are , the pressure at the bottom partition assembly 4 is , (Formula 2) where, ρ is the density of the liquid; P It is pressure; h is the vertical distance or depth from the free surface to that point; g is the acceleration due to gravity (approximately 9.8 ).

[0040] The effective area of ​​the first rebound valve 505 close to one end of the sleeve 7 is A, the total pressure at the corresponding partition component 4 is ,in is the total pressure at that location, is the pressure when filling with isolation fluid, In order to apply pressure from the upper pipe end of the cementing device when squeezing the isolation fluid into the pressurized expansion ring 501, the pressure of the spring in the rebound valve should meet Less than ,and Greater than The conditions ensure that the rebound valve will not open during injection and can only be opened when pressurized. The isolation liquid passes through the first, second and third water passages, and after the interior of the pressurized expansion ring 501 expands, it passes through the reflux lumen 508 to squeeze the closing valve 507 away from the sleeve 7, so that the interior of the pressurized expansion ring 501 is closed.

[0041] Second embodiment: The graded cementing device can also be used for one-time cementing in relatively uniform oil wells or oil wells with a shorter depth. The cementing device is first placed in the oil well, and drilling fluid is first pumped into the casing 7. After the drilling fluid washes the mud cake in the annulus, spacer fluid and cement slurry are injected into the casing 7. The spacer fluid is used to completely separate the cement slurry and the drilling fluid. As the pump is pumped, the cement slurry completely squeezes the spacer fluid and the drilling fluid out of the annulus. At the wellhead, a circulating pump is used to perform extraction operations, and a certain volume of cement slurry is injected through the corresponding design elevation. For example, the volume of the annulus is V , then the injection is greater than V The cement slurry is filled in the casing 7 (to prevent excessive outflow of cement slurry from the wellhead), and then an open rubber plug 601 is immediately placed, and drilling fluid or isolation fluid is added to the casing 7 to be pressurized by pumping until the rubber plug touches the bottom and the cement mortar inside the casing 7 is completely squeezed out. After further pressurization, the isolation fluid injected later passes through the inside of the three cavities and enters the inside of the pressurized expansion ring 501, squeezing the cement inside the annulus to fix the casing.

[0042] Therefore, when this embodiment is implemented, the one-way valve mechanism 11 inside the bottom floating foot 2 is used as a closed control valve to prevent the cement inside the annulus from flowing back. The floating foot 2 and the floating hoop 12 are used to guide the cement injector when it is lowered. When it is lowered, the roller 304 of the centering straightening assembly 3 contacts the well wall for straightening to ensure the axial coincidence degree between the cement injector and the inside of the oil well, that is, the centering degree. Similarly, the telescopic plate 303 is used to telescope inside the square casing 302, and the square casing 302 is used to rotate around the mounting ring 301 by hinge, so as to convert the movement of the roller 304 toward the casing 7 due to the squeezing of the well wall into the retraction of the two telescopic plates 303 toward the inside of the square casing 302, so as to ensure that the two mounting rings 301 do not move, thereby increasing the stability of the straightening device on the casing 7 and the fixity of its position. After detecting the inside of the oil well, the straightening device pre-installed on the casing 7 can play a greater role.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A packer-type staged cementing device, characterized in that: include: A closed sleeve member (1), the closed sleeve member (1) comprising a plurality of sleeves (7) uniformly distributed along the axial direction, gaps between the sleeves (7), the sleeves (7) being connected by a connecting sleeve (8), the outer side wall of the connecting sleeve (8) being provided with a plurality of uniformly distributed flow guide holes (9), and the outer sides of the sleeves (7) being provided with uniformly distributed limit clamps (10); A floating foot (2), the floating foot (2) being arranged at the outer bottom end of the closed sleeve member (1), a one-way valve mechanism (11) being arranged inside the floating foot (2), and a floating hoop (12) being arranged on the outer lower side of the closed sleeve member (1); A centering and straightening assembly (3), wherein the centering and straightening assembly (3) is arranged on each sleeve (7), and the centering and straightening assembly (3) is located between two limit clamps (10) of the same sleeve (7); A partition component (4), wherein the partition component (4) is arranged at a gap between the sleeves (7); A casing outer sealing member (5), wherein the casing outer sealing member (5) is arranged outside the casing (7); An operating rubber plug mechanism (6), wherein the operating rubber plug mechanism (6) is arranged inside the sleeve (7).

2. The isolation type staged cementing device according to claim 1, characterized in that: The one-way valve mechanism (11) comprises a ball seat (1101) arranged inside the floating foot (2), the center of the ball seat (1101) is a circular hole connected up and down, the upper edge of the ball seat (1101) is provided with a plurality of flow bottom holes (1102) distributed around the central circular hole, the upper end of the ball seat (1101) is provided with a valve ball (1103) used in conjunction with the circular hole at the center, the upper end of the floating foot (2) is a closing end used in conjunction with the valve ball (1103), the interior of the floating foot (2) and the interior of the sleeve (7) are through-connected, and the valve ball (1103) can move up and down between the ball seat (1101) and the closing end.

3. The isolation type staged cementing device according to claim 1, characterized in that: The centering and straightening assembly (3) comprises a mounting ring (301), the mounting ring (301) being arranged between two limit clamping rings (10) on the same sleeve (7), a plurality of evenly distributed square sleeves (302) being hingedly connected on the mutually adjacent sides of the mounting ring (301), a telescopic plate (303) being inserted inside the square sleeve (302), the other ends of the telescopic plates (303) being inserted inside the square sleeve (302) being hingedly connected to each other, and rollers (304) being arranged at the hinges between the telescopic plates (303) via bearings; Two insertion rods (305) are fixedly connected to the sides of the square sleeve (302) that are away from each other. The end of the telescopic plate (303) inserted into the square sleeve (302) is provided with two evenly distributed connection holes (306). The insertion rods (305) are inserted into the connection holes (306). The outside of the insertion rods (305) is sleeved with a compression spring (307) used in conjunction with the telescopic plate (303).

4. The isolation type staged cementing device according to claim 3, characterized in that: The rod end of the insertion rod (305) away from the square sleeve (302) is fixedly connected to an anti-slip block (308), and the end of the connection hole (306) away from the roller (304) is embedded with a limit ring (309) used in conjunction with the anti-slip block (308).

5. The isolation type staged cementing device according to claim 1, characterized in that: The partition assembly (4) comprises a plurality of movable collars (401) arranged in the gaps between the sleeves (7), the movable collars (401) being movable up and down in the gaps between the sleeves (7), and positioning retaining rings (402) being arranged inside the movable collars (401), the inner diameter of the positioning retaining rings (402) gradually decreasing from top to bottom; The upper end of the outer portion of the movable collar (401) is provided with a plurality of evenly distributed limiting holes (403); the lower ends of the spaces between the sleeves (7) are fixedly connected with a plurality of evenly distributed guide rods (404); the guide rods (404) and the inner portions of the limiting holes (403) are adapted to each other; the outer portions of the guide rods (404) are sleeved with control springs (405) used in conjunction with the movable collar (401); and the control springs (405) are located on the lower side of the outer portion of the movable collar (401).

6. The isolation type staged cementing device according to claim 1, characterized in that: The casing outer sealing member (5) comprises a plurality of pressurized expansion rings (501) evenly distributed on the casing (7); a first water passage cavity (502), a second water passage cavity (503) and a third water passage cavity (504) are respectively provided on one side of the interior of the pressurized expansion ring (501) from bottom to top; the interior of the first water passage cavity (502) is connected to the interior of the casing (7); an end of the second water passage cavity (503) close to the casing (7) is connected to the middle of the first water passage cavity (502); the middle of the second water passage cavity (503) is connected to the middle of the third water passage cavity (504); and the middle of the third water passage cavity (504) is connected to the bottom of the interior of the pressurized expansion ring (501); A first rebound valve (505) is arranged inside the first water passage (502), a second rebound valve (506) is arranged inside the second water passage (503), a horizontally movable closing valve (507) is arranged inside the third water passage (504), a reflux lumen (508) is provided on the inner wall of the pressurized expansion ring (501) close to the water passage, and the upper end of the pressurized expansion ring (501) and the inner side of the third water passage (504) close to the sleeve (7) are connected via the reflux lumen (508).

7. The isolation type staged cementing device according to claim 6, characterized in that: The first rebound valve (505) can control the opening and closing of the connection between the first water passage (502) and the second water passage (503), the second rebound valve (506) can control the opening and closing of the connection between the second water passage (503) and the third water passage (504), and the closing valve (507) can control the opening and closing of the connection between the third water passage (504) and the pressurized expansion ring (501) and the connection between the third water passage (504) and the second water passage (503).

8. The isolation type staged cementing device according to claim 1, characterized in that: The operating rubber plug mechanism (6) comprises a plurality of opening rubber plugs (601) and closing rubber plugs (602); the tail end of the closing rubber plug (602) is made of a rigid material, and the radius of the tail end of the closing rubber plug (602) gradually decreases from top to bottom.

9. The isolation type staged cementing device according to claim 5 or 8, characterized in that: The base radius of the tail end of the open rubber plug (601) is smaller than the inner diameter of all the positioning retaining rings (402), and the tail end of the closed rubber plug (602) is matched with the positioning retaining ring (402).

10. The isolation type staged cementing device according to claim 5, characterized in that: The inner wall of the connecting sleeve (8) is provided with a sealing bushing (13) used to cooperate with the gap between the sleeves (7); when the movable collar (401) moves to the bottom end in the gap between the sleeves (7), the guide hole (9) is not blocked by the movable collar (401).

Images