A multifunctional compensating nipple for top drive casing running device

Abstract

The invention discloses a multifunctional compensating nipple for a top drive casing lowering device, comprising a main shaft, an upper bearing end cover, an intermediate spline sleeve, a lower sealing sleeve and a compensating unit. The middle part of the outer wall of the main shaft is clamped with an intermediate spline sleeve, the upper end of the intermediate spline sleeve is connected to the upper bearing end cover by threads, the lower end of the intermediate spline sleeve is connected to the lower sealing sleeve by threads, the lower end of the main shaft is inserted into the inner cavity of the lower sealing sleeve, and a guide ring and a sealing ring are arranged between the main shaft and the inner cavity, and a compensating unit is arranged in an annular cavity formed by the main shaft, the intermediate spline sleeve and the lower sealing sleeve, the compensating unit compensates for the weight of the casing lowering tool and the casing, prevents the damage of the precision thread due to excessive collision stress when the casing is lowered, and reduces the probability of operation accidents such as wrong threading during the threading process. The invention adopts a fully mechanical structure, improves the applicability to top drives and casing lowering devices of different models, and is convenient for installation, use and maintenance at the operation site.

Description

Technical Field

[0001] The invention relates to the field of oil drilling machinery and equipment, in particular to a short section which can be used to compensate for a casing lowering device, casing weight and casing thread length during casing lowering operation. Background Art

[0002] During the oil drilling process, casing running operation refers to the operation of lowering casing with a diameter smaller than that of the open hole into a pre-designed well section through a specific casing running device. It is a very important operation process in the drilling project, and the top drive casing running device is a new type of casing running device. The device has the ability to rotate the casing and circulate drilling fluid, which greatly reduces the probability of operating accidents such as casing obstruction during the operation. However, this type of equipment also has some shortcomings during use. First, during the casing running process, the weight of the top drive, the casing running device and a single casing is all transferred to the balance hydraulic cylinder between the top drive and the traveling block through the connection interface between the equipment, resulting in the compensation stroke of the top drive balance hydraulic cylinder being completely compressed, and the balance is lost. The top drive casing running device and the single casing weight compensation function; secondly, since the main shaft of the top drive casing running device and the top drive main shaft are rigidly connected by threads, the lowering distance is difficult to control during the top drive lowering process. If the operation is not precise, the weight of the casing running device and the single casing will be fully loaded on the casing pile and the single casing thread, which is very likely to cause the casing threads to collide with each other and cause thread damage; in addition, since the female thread on the casing pile needs to bear the entire weight of the casing running device and the single casing, it is very easy for the male thread and the female thread to be misthreaded or the thread to be damaged during the casing screwing process; finally, when using the top drive casing running device to perform single casing threading and unthreading operations, it is not easy to compensate for the length of the casing thread joint during the threading process. Summary of the invention

[0003] The purpose of the present invention is to provide a multifunctional compensating nipple for a top drive casing running device, so as to solve the problems that when a conventional top drive casing running device is used for casing running operation, weight concentration causes the top drive balancing hydraulic cylinder to lose its weight compensation function; the lowering distance is difficult to control, causing casing threads to collide with each other and cause thread damage; the male thread and the female thread are very likely to be crossed or the thread is damaged during the casing screwing process; and it is difficult to compensate for the length of the casing threaded joint during the screwing operation.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A multifunctional compensating nipple for a top drive casing device: comprising a main shaft, an upper bearing end cover, an intermediate spline sleeve, a lower sealing sleeve and a compensating unit, wherein the main shaft is arranged vertically, an intermediate spline sleeve is clamped in the middle of the outer wall of the main shaft, the upper end of the intermediate spline sleeve is connected to the upper bearing end cover by threads, a guide ring 2 and a dust ring are arranged between the upper end of the upper bearing end cover and the outer wall of the main shaft, the lower end of the intermediate spline sleeve is connected to the lower sealing sleeve by threads, the lower end of the main shaft is inserted into the inner cavity of the lower sealing sleeve, and a guide ring 1 and a sealing ring are arranged between the inner cavity, and a compensating unit is arranged in the annular cavity formed by the main shaft, the intermediate spline sleeve and the lower sealing sleeve;

[0006] The upper part of the outer wall of the main shaft is provided with a bearing boss, which is installed in the annular gap between the upper bearing end cover and the upper end face of the intermediate spline sleeve. The middle part of the main shaft is processed with an external spline, and the lower part of the main shaft is processed with a shoulder. The end face of the shoulder is provided with an array of bolt holes along the axial direction, and the end of the main shaft is provided with a sealing guide groove along the circumferential direction. A mud circulation channel is opened at the axis of the main shaft;

[0007] The compensation unit includes a cover plate, an upper spring seat, a compensation spring and a lower spring seat. The cover plate is pressed against the lower end of the external spline on the main shaft. The diameter of the cover plate is smaller than the diameter of the load-bearing end face. The upper spring seat is connected to the cover plate by screw 1. A bushing is provided between the upper spring seat and the main shaft. The lower spring seat is fixed to the lower shoulder of the main shaft by screw 2. The compensation spring is arranged between the upper spring seat and the lower spring seat. The compensation spring is in a pre-stressed state when installed, and the maximum elastic force is less than or equal to the sum of the weight of the top drive casing device and a single casing.

[0008] Preferably, the main shaft is made of alloy steel.

[0009] Preferably, the inner wall of the upper end of the intermediate spline sleeve is axially processed with an internal spline, the outer wall of the intermediate spline sleeve boss is radially provided with a plurality of oil cup mounting holes, an oil cup is provided in the oil cup mounting hole, and a load-bearing end face is processed in the inner cavity of the intermediate spline sleeve.

[0010] Preferably, the length of the internal spline is greater than the sum of the length of the external spline on the main shaft and the maximum thread length of the casing thread, and the internal spline and the external spline form a pair of spline pairs.

[0011] Preferably, the outer surfaces of the upper load-bearing end cover, the middle spline sleeve and the lower sealing sleeve are all processed with a plurality of flat surfaces for clamping a wrench when the threads are screwed on.

[0012] The use process of the present invention is:

[0013] When not in operation, the lower sealing sleeve does not suspend a load, the compensation spring is in an extended state, and the elastic force of the compensation spring pushes the load-bearing end surface of the intermediate spline sleeve upward through the upper spring seat and the cover plate under the guidance of the bushing until the cover plate contacts the lower end of the spline on the main shaft.

[0014] In the working state, the top drive casing device and the casing are connected to the male thread of the lower sealing short section, and a hanging load is applied to the lower sealing sleeve. Under the weight of the top drive casing device and the casing, the bearing end face of the intermediate spline sleeve presses down the cover plate, and then the load is transferred to the lower spring seat through the compensation spring. Since the lower spring seat is connected to the main shaft through screw 2, the elastic force of the compensation spring is transferred to the main shaft, thereby realizing the weight compensation function for the top drive casing device and the casing. When the compression amount of the compensation spring reaches a certain extent, the upper end face of the bearing boss on the main shaft contacts the lower end face of the upper bearing end cover, limiting the compensation spring from being further compressed, and preventing it from being damaged due to excessive compression.

[0015] After the top drive casing lowering device lowers a single casing onto the casing pile, the top drive continues to be lowered. At this time, the main shaft moves downward under the guidance of the external spline and the internal spline on the intermediate spline sleeve until the main shaft lowering distance is greater than or equal to the length of a casing thread. At this time, the top drive lowering distance is controlled by the distance measuring instrument in the driller's room. After the lowering is completed, the top drive is started to make up the operation. The make-up torque is transmitted to the internal spline through the external spline, and then to the lower sealing sleeve, and finally the make-up torque is transmitted to the casing. As the casing male thread is screwed into the female thread on the casing pile, the distance between the two thread shoulders gradually decreases. At this time, the external spline and the internal spline provide a guiding role. As the make-up process proceeds, the casing drives the lower sealing sleeve and the intermediate spline sleeve to move downward, thereby realizing the function of compensating the casing thread length during the make-up process of the present invention.

[0016] During the process of lowering and making up the casing, the external spline on the main shaft cooperates with the internal spline on the intermediate spline sleeve to meet the requirements of transmitting the top drive torque to achieve the operation of making up, making up or rotating the casing string of a single casing. The length of the internal spline should be greater than the sum of the length of the external spline and the length of the compensating thread.

[0017] During the entire working process, the upper end of the mud channel in the spindle mandrel is connected to the mud channel of the mandrel of the top drive casing lowering device, and the lower end of the mud channel is connected to the mud channel in the mandrel of the casing lowering tool. A sealing guide groove is machined at the end of the spindle mandrel, and the guide ring and the sealing ring are installed in the sealing guide groove to form a sealed cavity with the lower sealing sleeve. When the present invention performs weight compensation or thread compensation, the lower sealing sleeve moves relative to the spindle, and the guide ring and the sealing ring always seal the sealing chamber of the lower sleeve, realizing the dynamic sealing function of the present invention for mud.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention has a compensation unit installed on the main shaft. During the casing lowering operation, part of the casing lowering tool and the weight of a single casing are transferred from the casing joint thread to the main shaft of the present invention under the action of the compensation unit, which greatly reduces the collision load between the single casing and the casing joint on the casing pile during the lowering of the single casing, prevents the damage of the precise casing thread due to excessive collision stress during the lowering of the casing, and reduces the load borne by the thread during the threading and unthreading operations, thereby reducing the probability of operating accidents such as wrong threading and thread damage during the threading process.

[0020] (2) The external splines on the main shaft of the present invention cooperate with the internal splines of the intermediate spline sleeve to form a pair of spline pairs, thereby being able to meet the requirements of transmitting the top drive torque to achieve the operation of making and breaking out a single casing or rotating the casing string. The internal and external splines can slide relative to each other, providing conditions for the realization of the weight compensation function and the thread length compensation function of the present invention.

[0021] (3) The compensation unit of the present invention is integrally nested on the main shaft, which facilitates on-site connection and disassembly of the connecting thread between the intermediate spline sleeve and the lower sealing sleeve, simplifies the internal structure of the entire multifunctional compensation nipple, and has a simple and reliable structure, which reduces the occurrence of failures and improves equipment reliability.

[0022] (4) A bearing boss is machined on the main shaft of the present invention to meet the strength requirement of suspending the weight of all casing columns and the casing running device during the casing running operation.

[0023] (5) The main shaft of the present invention is processed with a mud circulation channel and a sealing guide groove, which, by cooperating with the lower sealing sleeve, can realize the mud injection and circulation functions during the casing operation and the dynamic sealing of the mud during the compensation operation.

[0024] (6) The present invention adopts a fully mechanical structure, eliminating the requirements for external interface configuration of hydraulic and electrical equipment, improving the applicability of the present invention to top drives and casing devices of different models, and achieving the design functions of the present invention without making major changes to existing equipment. At the same time, it is also convenient for the installation, use and maintenance of the present invention at the work site.

[0025] (7) In the present invention, the inner spline and the outer spline are lubricated by an oil cup to ensure the working performance when the main shaft and the intermediate spline sleeve slide against each other.

[0026] (8) In the present invention, a bushing is provided between the upper spring seat and the main shaft to guide the compensation spring and prevent the upper spring seat from generating excessive friction on the main shaft, thereby ensuring the normal operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a schematic diagram of the installation position of the present invention in the casing running system.

[0028] Figure 2 It is the overall external axonometric view of the present invention.

[0029] Figure 3 It is a cross-sectional view of the present invention in a non-working state.

[0030] Figure 4 It is a cross-sectional view of the working state of the present invention.

[0031] Figure 5 for Figure 2 Schematic diagram of the main shaft structure of the present invention.

[0032] Figure 6 for Figure 2 Schematic diagram of the intermediate spline sleeve of the present invention.

[0033] Figure 7 for Figure 3 A cross-sectional view of the compensation unit of the present invention.

[0034] Figure 8 for Figure 7 Schematic diagram of the bottom fixing structure of the compensation unit of the present invention.

[0035] Fig. 9 for Figure 3 Schematic diagram of the sealing guide structure in the lower sealing sleeve of the present invention.

[0036] Fig.10 It is a cross-sectional view of the overall structure of the present invention.

[0037] In the figure: 1. top drive, 2. multifunctional compensating short section, 3. top drive casing device, 4. casing, 5. main shaft, 5-1. bearing platform, 5-2. external spline, 5-3. sealing guide groove, 5-4. mud channel, 5-5. shoulder, 6. upper bearing end cover, 7. oil cup, 8. intermediate spline sleeve, 8-1. internal spline, 8-2. oil cup mounting hole, 8-3. bearing end face, 9. lower sealing sleeve, 10. compensation unit, 10-1. cover plate, 10-2. screw one, 10-3. upper spring seat, 10-4. bushing, 10-6. compensation spring, 10-7. lower spring seat, 10-8. screw two, 11. guide ring one, 12. sealing ring, 13. guide ring two, 14. dust ring. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0039] like Figure 1-Figure 9A multifunctional compensating nipple for a top drive casing lowering device is shown, comprising a main shaft 5, an upper bearing end cover 6, an intermediate spline sleeve 8, a lower sealing sleeve 9 and a compensating unit 10. The main shaft 5 is vertically arranged, and an intermediate spline sleeve 8 is clamped in the middle of the outer wall of the main shaft 5. The upper end of the intermediate spline sleeve 8 is connected to the upper bearing end cover 6 by threads, and a guide ring 13 and a dust ring 14 are provided between the upper end of the upper bearing end cover 6 and the outer wall of the main shaft. The lower end of the intermediate spline sleeve 8 is connected to the lower sealing sleeve 9 by threads. The lower end of the main shaft 5 is inserted into the inner cavity of the lower sealing sleeve 9, and a guide ring 11 and a sealing ring 12 are provided between the inner cavity, and the compensating unit 10 is provided in the annular cavity formed by the main shaft 5, the intermediate spline sleeve 8 and the lower sealing sleeve 9.

[0040] A bearing boss 5-1 is provided on the upper part of the outer wall of the main shaft 5, and the bearing boss 5-1 is installed in the annular gap between the upper bearing end cover 6 and the upper end face of the intermediate spline sleeve 8. An external spline 5-2 is processed in the middle part of the main shaft 5, and a shoulder 5-5 is processed in the lower part of the main shaft 5. An array of bolt holes is provided on the end face of the shoulder 5-5 along the axial direction, a sealing guide groove 5-3 is provided at the end of the main shaft 5 along the circumferential direction, and a mud circulation channel 5-4 is opened at the axis of the main shaft 5.

[0041] The main shaft 5 is made of alloy steel.

[0042] The inner wall of the upper end of the middle spline sleeve 8 is axially processed with an inner spline 8-1, the outer wall of the boss of the middle spline sleeve 8 is radially provided with several oil cup mounting holes 8-2, the oil cup mounting holes 8-2 are provided with oil cups 7, and the inner cavity of the middle spline sleeve 8 is processed with a load-bearing end face 8-3.

[0043] The length of the internal spline 8-1 is greater than the sum of the length of the external spline 5-2 on the main shaft 5 and the maximum thread length of the casing thread. The internal spline 8-1 and the external spline 5-2 form a pair of spline pairs.

[0044] The compensation unit 10 includes a cover plate 10-1, an upper spring seat 10-3, a compensation spring 10-6 and a lower spring seat 10-7. The cover plate 10-1 is pressed against the lower end of the external spline 5-2 on the main shaft 5. The diameter of the cover plate 10-1 is smaller than the diameter of the load-bearing end surface 8-3. The upper spring seat 10-3 is connected to the cover plate 10-1 by a screw 10-2. A bushing 10-4 is provided between the upper spring seat 10-3 and the main shaft 5. The lower spring seat 10-7 is fixed to the lower shoulder 5-5 of the main shaft 5 by a screw 10-8. The compensation spring 10-6 is provided between the upper spring seat 10-3 and the lower spring seat 10-7. The compensation spring 10-6 is in a pre-stressed state when installed, and the maximum elastic force is less than or equal to the sum of the weight of the top drive casing device and a single casing.

[0045] The outer surfaces of the upper bearing end cover 6, the middle spline sleeve 8 and the lower sealing sleeve 9 are all processed with a plurality of flat surfaces for holding a wrench when the threads are buckled.

[0046] The use process of the present invention is:

[0047] When in the non-working state, the lower sealing sleeve 9 does not hang any load, and the compensation spring 10-6 is in an extended state. The elastic force of the compensation spring 10-6 pushes the load-bearing end face 8-3 of the intermediate spline sleeve 8 upward through the upper spring seat 10-3 and the cover plate 10-1 under the guidance of the bushing 10-4 until the cover plate 10-1 contacts the lower end of the spline 5-2 on the main shaft 5.

[0048] In the working state, the top drive casing device 3 and the casing 4 are connected to the male thread of the lower sealing short section 9, and a hanging load is applied to the lower sealing sleeve 9. Under the weight of the top drive casing device 3 and the casing 4, the middle spline sleeve bearing end face 8-3 presses down the cover plate 10-1, and then transfers the load to the lower spring seat 10-7 through the compensation spring 10-6. Since the lower spring seat 10-7 is connected to the main shaft 5 through the screw 10-8, the elastic force of the compensation spring 10-6 is transferred to the main shaft 5, thereby realizing the weight compensation function of the top drive casing device 3 and the casing 4. When the compression amount of the compensation spring 10-6 reaches a certain extent, the upper end face of the bearing boss 5-1 on the main shaft 5 contacts the lower end face of the upper bearing end cover 6, which limits the compensation spring 10-6 from being further compressed to prevent it from being damaged due to excessive compression.

[0049] After the top drive casing lowering device 3 lowers a single casing 4 onto the casing pile, the top drive 1 continues to be lowered. At this time, the main shaft 5 moves downward under the guidance of the external spline 5-2 and the internal spline 8-1 on the intermediate spline sleeve 8, until the lowering distance of the main shaft 5 is greater than or equal to the length of a casing thread. At this time, the distance measuring instrument in the driller's room controls the lowering distance of the top drive. After the lowering is completed, the top drive 1 is started to make up the operation. The make-up torque is transmitted to the internal spline 8-1 through the external spline 5-2, and then to the lower sealing sleeve 9, and finally the make-up torque is transmitted to the casing 4. As the male thread of the casing 4 is screwed into the female thread on the casing pile, the distance between the two thread shoulders gradually decreases. At this time, the external spline 5-2 and the internal spline 8-1 provide a guiding effect. As the make-up process proceeds, the casing 4 drives the lower sealing sleeve 9 and the intermediate spline sleeve 8 to move downward, thereby realizing the function of compensating the casing thread length during the make-up process of the present invention.

[0050] During the process of lowering and making up the casing 4, the external spline 5-2 on the main shaft 5 cooperates with the internal spline 8-1 on the intermediate spline sleeve 8 to meet the requirements of transmitting the top drive torque to achieve the operation of making up, making up or rotating the casing string of a single casing. The length of the internal spline 8-1 is greater than the sum of the length of the external spline 5-2 and the length of the compensating thread.

[0051] During the entire working process, the upper end of the mud channel 5-4 in the mandrel of the main shaft 5 is connected to the mandrel mud channel of the top drive casing lowering device 3, and the lower end of the mud channel 5-4 is connected to the mud channel in the mandrel of the casing lowering tool. A sealing guide groove 5-3 is machined at the end of the mandrel of the main shaft 5, and the guide ring 11 and the sealing ring 12 are installed in the sealing guide groove 5-3, forming a sealed cavity with the lower sealing sleeve 9. When the present invention performs weight compensation or thread compensation, the lower sealing sleeve 9 moves relative to the main shaft 5, and the guide ring 11 and the sealing ring 12 always seal the sealed chamber of the lower sleeve 9, realizing the dynamic sealing function of the present invention for mud.

[0052] The present invention has a compensation unit installed on the main shaft. During the casing lowering operation, part of the casing lowering tool and the weight of a single casing are transferred from the casing joint thread to the main shaft of the present invention under the action of the compensation unit, which greatly reduces the collision load between the single casing and the casing joint on the casing pile during the lowering of the single casing, and prevents the damage of the precision thread of the casing due to excessive collision stress during the lowering of the casing. At the same time, it reduces the burden on the thread during the buckling and unbuckling operations, and reduces the probability of operating accidents such as wrong buckling and thread damage during the buckling process. The present invention adopts a fully mechanical structure, eliminates the requirements for the external interface configuration of hydraulic and electrical equipment, improves the applicability of the present invention to different models of top drives and casing lowering devices, and can achieve the design function of the present invention without making major changes to the existing equipment. At the same time, it is also convenient for the invention to be installed, used and maintained at the operation site.

Claims

1. A multifunctional compensating nipple for a top drive casing running device, characterized in that: The invention comprises a main shaft (5), an upper bearing end cover (6), an intermediate spline sleeve (8), a lower sealing sleeve (9) and a compensation unit (10), wherein the main shaft (5) is arranged vertically, an intermediate spline sleeve (8) is clamped in the middle of the outer wall of the main shaft (5), the upper end of the intermediate spline sleeve (8) is connected to the upper bearing end cover (6) by threads, a guide ring 2 (13) and a dust ring (14) are provided between the upper end of the upper bearing end cover (6) and the outer wall of the main shaft, the lower end of the intermediate spline sleeve (8) is connected to the lower sealing sleeve (9) by threads, the lower end of the main shaft (5) is inserted into the inner cavity of the lower sealing sleeve (9), and a guide ring 1 (11) and a sealing ring (12) are provided between the lower end of the main shaft (5) and the inner cavity, and a compensation unit (10) is provided in the annular cavity formed by the main shaft (5), the intermediate spline sleeve (8) and the lower sealing sleeve (9); The upper portion of the outer wall of the main shaft (5) is provided with a bearing boss (5-1), the bearing boss (5-1) being installed in the annular gap between the upper bearing end cover (6) and the upper end surface of the intermediate spline sleeve (8), the middle portion of the main shaft (5) is processed with an external spline (5-2), the lower portion of the main shaft (5) is processed with a shoulder (5-5), the end surface of the shoulder (5-5) is provided with a plurality of bolt holes in the axial direction, the end of the main shaft (5) is provided with a sealing guide groove (5-3) in the circumferential direction, and the axis of the main shaft (5) is provided with a mud circulation channel (5-4); The compensation unit (10) comprises a cover plate (10-1), an upper spring seat (10-3), a compensation spring (10-6) and a lower spring seat (10-7); the cover plate (10-1) is pressed against the lower end of the external spline (5-2) on the main shaft (5); the diameter of the cover plate (10-1) is smaller than the diameter of the bearing end surface (8-3); the upper spring seat (10-3) is connected to the cover plate (10-1) via a screw (10-2); A bushing (10-4) is provided between the upper spring seat (10-3) and the main shaft (5); the lower spring seat (10-7) is fixed to the lower shoulder (5-5) of the main shaft (5) by means of a second screw (10-8); a compensation spring (10-6) is provided between the upper spring seat (10-3) and the lower spring seat (10-7); the compensation spring (10-6) is in a pre-stressed state when installed, and the maximum elastic force is less than or equal to the sum of the weight of the top drive casing device and a single casing.

2. A multifunctional compensating nipple for a top drive casing running device according to claim 1, characterized in that: The main shaft (5) is made of alloy steel.

3. A multifunctional compensating nipple for a top drive casing running device according to claim 1 or 2, characterized in that: An inner spline (8-1) is machined along the axial direction on the inner wall of the upper end of the intermediate spline sleeve (8), a plurality of oil cup mounting holes (8-2) are radially provided on the outer wall of the boss of the intermediate spline sleeve (8), an oil cup (7) is provided in the oil cup mounting hole (8-2), and a bearing end surface (8-3) is machined in the inner cavity of the intermediate spline sleeve (8).

4. The multifunctional compensating nipple for a top drive casing running device according to claim 3, characterized in that: The length of the internal spline (8-1) is greater than the sum of the length of the external spline (5-2) on the main shaft (5) and the maximum thread length of the casing thread, and the internal spline (8-1) and the external spline (5-2) form a pair of spline pairs.

5. The multifunctional compensating nipple for a top drive casing running device according to claim 4, characterized in that: The outer surfaces of the upper bearing end cover (6), the middle spline sleeve (8) and the lower sealing sleeve (9) are all processed with a plurality of flat surfaces for holding a wrench when the threads are buckled.

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