Steel coiled pipe built-in cable downhole connection short section

Abstract

The present invention is a steel continuous pipe built-in cable downhole connection short section, comprising an outer tube, wherein the outer tube has a main channel, an oil passage channel and a cable channel, wherein the main channel is connected to the upper end of the outer tube, and the oil passage channel and the cable channel are both connected to the main channel, wherein the axes of the oil passage channel and the cable channel deviate from the center line of the main channel, and the lower part of the oil passage channel is connected to the lower end center of the outer tube after being deflected, and the cable channel can allow the built-in cable to pass through. A first sealing rubber tube and a slip connector are provided in the cable channel, and the built-in cable can pass through the first sealing rubber tube and the slip connector in sequence, wherein the first sealing rubber tube is arranged in an axially compressed state and can be sealed against the built-in cable, and wherein the slip connector has a slip that can contract radially and has teeth on the inner wall, wherein the slip is arranged in a contracted state and the teeth can bite the built-in cable. The present invention can simultaneously meet the functions of fixing and sealing the downhole cable, and has stable suspension and sealing, simple structure and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of oil production or operation of a steel coiled pipe with an internal cable, and in particular to a downhole connecting nipple of a steel coiled pipe with an internal cable. Background Art

[0002] In oilfield production, the liquid in the oil well can be lifted to the ground through the lifting operation of the electric submersible pump. The electric submersible pump in the oil well needs the motor to provide it with electric energy to perform the lifting operation. The electric energy needs to be transmitted through the cable. Therefore, it is necessary to connect a section of cable between the ground control cabinet and the motor at the lower end of the electric submersible pump, and the cable needs to be fixed, otherwise the construction operation cannot be realized. The traditional rodless oil production method is to directly connect the electric submersible pump by bundling the cable outside the pipe. The operation process is complicated, the operation efficiency is low, the operation cycle is long, and the cable is very easy to be damaged during the operation or the operation of the motor. Compared with the traditional oil production process, the process of connecting the electric submersible pump with the cable built into the continuous pipe has great advantages. The cable is set inside the continuous pipe, which can greatly reduce the damage to the cable. Moreover, the cable is built into the inner cavity of the continuous oil pipe, which avoids the cable from being stuck when the equipment in the maintenance well lifts the oil pipe, greatly simplifying the operation of the equipment in the maintenance well. At the same time, the cable can heat up when it is powered on, which reduces the rate of wax deposition on the inner wall of the continuous oil pipe, which can reduce the frequency of daily maintenance and well washing, and reduce production costs.

[0003] However, the existing coiled tube is not stable enough when setting the cable. It only fixes the part of the cable located at the openings at both ends of the coiled tube, resulting in the long section of the cable in the coiled tube being basically unrestricted, so that the product in the coiled tube contacts the cable during transportation, which easily causes the cable to shake under force and collide with its inner wall, resulting in damage to the cable, thereby reducing the service life of the cable and posing a safety hazard. In addition, there is a lack of sealing measures when the cable is passed out, so it is easy for air and liquid to enter the interior.

[0004] At present, there are two main types of patents about cables built into continuous pipes. One type is the underground fixation of built-in cables. For example, the Chinese utility model patent with the authorization announcement number CN 210948537 U and the authorization announcement date July 7, 2020, uses a cable installation block, a cable trough, a limit mechanism and a fixing buckle. By pulling the pull rope, the first limit buckle and the second limit buckle are simultaneously subjected to force and move toward the center of the connecting pipe, so that the longer section of cable inside the connecting pipe is squeezed and limited, and then the cable enters the positioning groove stably, thereby ensuring the limit fixation of the cable. Although this measure solves the problem of underground cables being damaged by friction due to shaking, it does not take into account the sealing that needs to be done when the cable is passed out, and has no certain practical value. The other is the sealing of the built-in cable underground, such as the Chinese utility model patent with authorization announcement number CN 204827415 U and authorization announcement date of December 2, 2015, and the Chinese invention patent with authorization announcement number CN 110649423 B and publication date of January 3, 2020, both of which have achieved cable sealing. Although the sealing is achieved, it is often necessary to divide the cable into multiple sections for joints, resulting in difficulties in sealing and unreliable use of both the cable break and the connection between the cable and the metal core, which leads to unstable signal transmission and even interruption of signal transmission in the transmission cable of the underground measurement and control instrument.

[0005] In addition, in the prior art, after the built-in cable is passed through the continuous pipe, it is basically connected to the lead-in cable of the electric submersible pump in the casing annulus. There is no protection measure at the joint between the built-in cable and the lead-in cable, which is very easy to be damaged.

[0006] With regard to the downhole suspension and sealing of the built-in cable in the continuous tubing pressure completion string, there is currently a lack of corresponding suspension devices or tools, supporting suspension process methods, supporting sealing methods, and protection measures for the joint between the built-in cable and the lead-in cable.

[0007] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes a downhole connection short section of a steel continuous pipe with a built-in cable to overcome the defects of the prior art. Summary of the invention

[0008] The object of the present invention is to provide a steel continuous pipe built-in cable downhole connecting nipple, which can simultaneously meet the functions of fixing and sealing the downhole cable, and has stable suspension and sealing, simple structure and low cost.

[0009] The object of the present invention is achieved in this way. A steel continuous pipe built-in cable downhole connection short section comprises an outer pipe; the outer pipe is provided with a main channel, an oil channel and a cable channel, the main channel is connected to the upper end of the outer pipe, the oil channel and the cable channel are both connected to the main channel, the axes of the oil channel and the cable channel are both deviated from the center line of the main channel, and the lower part of the oil channel is connected to the lower end center of the outer pipe after being deflected, and the cable channel can allow the built-in cable to pass through; a first sealing rubber tube and a slip connector are provided in the cable channel, the built-in cable can pass through the first sealing rubber tube and the slip connector in turn, the first sealing rubber tube is arranged in an axially compressed state and can be sealed against the built-in cable, the slip connector is provided with a slip that can be radially contracted and has teeth on the inner wall, the slip is arranged in a contracted state and the teeth can bite the built-in cable.

[0010] In a preferred embodiment of the present invention, the flow cross-sectional area of ​​the oil passage is the same as the flow cross-sectional area of ​​the steel coiled tubing.

[0011] In a preferred embodiment of the present invention, a first upper pressure ring and a first lower pressure ring are respectively provided at both ends of the first sealing rubber cylinder, and the first upper pressure ring is axially limited at the upper part of the cable channel; the cava connector also includes a tapered sleeve and a connecting pipe, and the tapered sleeve can be abutted against the first lower pressure ring; the tapered sleeve has an inner conical surface with a diameter gradually expanding downward, the outer wall of the cava is an outer conical surface matching the inner conical surface, and the cava is inserted into the tapered sleeve in a contracted state; the upper outer wall of the connecting pipe is threadedly connected to the lower inner wall of the cable channel, and the upper end of the connecting pipe can be abutted against the cava.

[0012] In a preferred embodiment of the present invention, the cava is a conical tube body with a longitudinal cut, the teeth are formed on the inner wall of the conical tube body, and the outer conical surface is formed on the outer wall of the conical tube body; a plurality of slits are formed on the tube wall of the conical tube body, and the slits extend to one of the ends of the conical tube body.

[0013] In a preferred embodiment of the present invention, the plurality of slits include a plurality of first slits and a plurality of second slits arranged alternately, the first slits extend upward to the upper end of the conical tube body, and the second slits extend downward to the lower end of the conical tube body.

[0014] In a preferred embodiment of the present invention, the upper end of the pipe is circumferentially fixedly connected to the lower end of the slip.

[0015] In a preferred embodiment of the present invention, an upper limit step and a lower limit step are formed on the inner wall of the cable channel, the first upper pressure ring can lean against the upper limit step, a limit ring is protruding outward from the lower part of the first lower pressure ring, the lower limit step is located above the limit ring, and can limit the axial position of the limit ring.

[0016] In a preferred embodiment of the present invention, an installation cavity is further provided in the outer tube, an opening is provided at a position of the tube wall of the outer tube corresponding to the installation cavity, and a pressure cover is sealed and connected at the opening; a limiting tube is sealed and fixed in the installation cavity, and the inner diameter of the limiting tube constitutes a cable channel; a notch is provided in the lower outer side wall of the outer tube, and the lower end of the installation cavity is connected to the notch through an oblique channel, and the leading cable of the submersible pump can be sealed and passed through the oblique channel, and the built-in cable and the leading cable can be connected in the installation cavity.

[0017] In a preferred embodiment of the present invention, the mounting cavity is a grease injection cavity, into which electrical insulating resin can be injected.

[0018] In a preferred embodiment of the present invention, the upper end of the installation cavity has an installation hole, the upper end of the limiting tube is threadedly connected to the installation hole, and a sealing ring is sandwiched between the limiting tube and the installation hole.

[0019] In a preferred embodiment of the present invention, a stepped hole with an increasing aperture is formed downwardly at the lower portion of the oblique channel, and a second upper pressure ring, a second sealing rubber tube, a second lower pressure ring and a hollow bolt are sequentially embedded in the stepped hole from top to bottom, the hollow bolt is threadedly connected to the hole wall of the stepped hole, and the hollow bolt can rest against the second lower pressure ring.

[0020] In a preferred embodiment of the present invention, the cross-section of the notch in the plane where the axis of the oil passage and the axis of the oblique channel are located is a trapezoid, and the lower base of the trapezoid corresponds to the opening end of the notch, the two waists of the trapezoid are both hypotenuses, and one of the hypotenuses is connected to the lower end of the oblique channel and is perpendicular to the axis of the oblique channel.

[0021] In a preferred embodiment of the present invention, the angle between the axis of the oblique channel and the axis of the outer tube is 5-10°, and the angle between the hypotenuse away from the oblique channel in the trapezoid and the axis of the outer tube is less than or equal to 30°.

[0022] In a preferred embodiment of the present invention, the outer tube includes an upper tube body, an intermediate tube body and a lower tube body which are sealed and connected in sequence from top to bottom, the main channel is formed in the upper tube body, the mounting cavity and the oblique channel are formed in the intermediate tube body; a part of the oil passage is formed in the intermediate tube body, and another part of the oil passage is formed in the lower tube body; the opening is opened on the intermediate tube body, a part of the notch is formed on the outer wall of the intermediate tube body, and another part is formed on the outer wall of the lower tube body.

[0023] As described above, the steel continuous pipe built-in cable downhole connection short section in the present invention realizes the installation of the built-in cable in the pipe through the cooperation of the oil passage and the cable passage, and does not affect the connection of the lower end of the entire connection short section with other tool strings. The radial contraction of the slips in the slip connector allows the teeth to bite the cable tightly, so that the cable can be suspended and fixed, and the suspension is stable; the axial compression of the first sealing rubber cylinder can ensure the sealing of the built-in cable when it passes through the cable channel, avoiding the air liquid in the oil sleeve ring from entering the outer pipe during use. The entire connection short section simultaneously meets the fixation and sealing of the built-in cable, and the suspension and sealing are reliable, the structure is simple, and the manufacturing and installation costs are low. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following drawings are intended only to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0025] Figure 1 : A cross-sectional view of a downhole connection short section of a steel continuous pipe with an internal cable provided by the present invention.

[0026] Figure 2 : A cross-sectional view of the outer tube provided by the present invention.

[0027] Figure 3 : A cross-sectional view of the position limiting tube provided by the present invention in cooperation with the first sealing rubber cylinder and the cava connector.

[0028] Figure 4 : A three-dimensional diagram of the first sealing rubber cylinder provided by the present invention.

[0029] Figure 5 : A cross-sectional view of the cone sleeve provided by the present invention.

[0030] Figure 6 : A three-dimensional diagram of the slip provided by the present invention.

[0031] Figure 7 : A cross-sectional view of the slip provided by the present invention.

[0032] Description of Figure Numbers:

[0033] 1. Outer tube; 11. Main channel; 12. Oil passage; 121. Axial channel; 122. Inclined channel; 13. Mounting cavity; 131. Gland; 132. Mounting hole; 14. Limiting tube; 141. Cable channel; 142. Upper limit step; 143. Lower limit step; 15. Oblique channel; 151. Step hole; 16. Notch; 17. Upper tube body; 18. Middle tube body; 19. Lower tube body;

[0034] 2. first sealing rubber cylinder; 20. plane; 21. first upper pressure ring; 22. first lower pressure ring; 221. limiting ring;

[0035] 3. Slip connector; 31. Conical sleeve; 311. Inner conical surface; 32. Slip; 321. Teeth; 322. Outer conical surface; 323. Longitudinal incision; 324. Slit; 3241. First slit; 3242. Second slit; 33. Connecting pipe;

[0036] 4. second sealing rubber cylinder; 41. second upper pressure ring; 42. second lower pressure ring;

[0037] 5. Hollow bolt. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0039] like Figures 1 to 7 As shown, this embodiment provides a steel continuous pipe built-in cable downhole connection short section, including an outer pipe 1. The outer pipe 1 has a main channel 11, an oil passage 12 and a cable channel 141. The main channel 11 is connected to the upper end of the outer pipe 1. The oil passage 12 and the cable channel 141 are both connected to the main channel 11. The axes of the oil passage 12 and the cable channel 141 are both deviated from the center line of the main channel 11, and the lower part of the oil passage 12 is connected to the lower end center of the outer pipe 1 after being deflected. The cable channel 141 can allow the built-in cable to pass through. A first sealing rubber tube 2 and a slip connector 3 are provided in the cable channel 141. The built-in cable can pass through the first sealing rubber tube 2 and the slip connector 3 in sequence. The first sealing rubber tube 2 is set in an axially compressed state and can be sealed against the built-in cable. The slip connector 3 has a slip 32 that can be radially contracted and has teeth 321 on the inner wall. The slip 32 is set in a contracted state and the teeth 321 can bite the built-in cable.

[0040] It can be understood that the center line of the main channel 11 is the center line of the outer tube 1, and the upper part of the oil passage 12 is arranged side by side with the cable channel 141. The cable channel 141 is used to pass the built-in cable, and the oil passage 12 is used to pass the oil. The oil passage 12 is deflected and passed to the center of the lower end of the outer tube 1, so as to be connected with other tool strings when used. The teeth 321 on the slip 32 can be serrated teeth or other shapes, as long as they can firmly bite the built-in cable after the slip 32 is radially contracted. The tip distance of the teeth 321 on the opposite side of the slip 32 matches the size of the armored tube of the armored cable. When used, the tooth tips of the teeth 321 of the slip 32 bite the armored tube of the armored cable to realize the suspension function. During installation, after the built-in cable passes through the first sealing rubber cylinder 2 and the slip connector 3, the first sealing rubber cylinder 2 is adjusted to the axial compression state, and the slip 32 is adjusted to the contracted state, so that the first sealing rubber cylinder 2 can be used to seal the built-in cable, and the slip 32 can be used to fix the cable.

[0041] Therefore, the steel continuous pipe built-in cable downhole connection short section in this embodiment realizes the installation of the built-in cable in the pipe through the cooperation of the oil passage 12 and the cable passage 141, and does not affect the connection of the lower end of the entire connection short section with other tool strings. The radial contraction of the slip 32 in the slip connector 3 enables the teeth 321 to bite the cable tightly, and the cable is suspended and fixed, and the suspension is stable; the axial compression of the first sealing rubber cylinder 2 can ensure the sealing of the built-in cable when it passes through the cable passage 141, and avoid the air liquid in the oil sleeve ring from entering the outer pipe 1 during use. The entire connection short section simultaneously meets the fixation and sealing of the built-in cable, and the suspension and sealing are reliable, the structure is simple, and the manufacturing and installation costs are low.

[0042] It should be noted that the upper and lower positions mentioned in the article refer to the connection of the short section according to the Figure 1 The upper and lower positions of the outer tube 1 when the axial direction is placed vertically are shown in the figure. The "top", "bottom", "upper", "lower" and similar expressions mentioned in this article are only for illustrative purposes and do not represent the only implementation method. In actual use, the connecting short section can be placed vertically or in other directions, depending on the specific needs. Generally, in actual applications, the connecting short section is mostly placed vertically along the axial direction of the outer tube 1.

[0043] In a specific implementation, the flow cross-sectional area of ​​the oil passage 12 is the same as the flow cross-sectional area of ​​the steel coiled pipe, so that no pressure drop is generated to avoid energy loss and the flow path is guaranteed.

[0044] Furthermore, in order to facilitate installation, the first sealing rubber cylinder 2 is adjusted to an axially compressed state, and the slips 32 are adjusted to a contracted state, such as Figure 1 , Figure 3 and Figure 6 As shown, a first upper pressure ring 21 and a first lower pressure ring 22 are respectively provided at both ends of the first sealing rubber cylinder 2, and the first upper pressure ring 21 is axially limited at the upper part of the cable channel 141. The slip connector 3 also includes a cone sleeve 31 and a pipe 33, and the cone sleeve 31 can be pressed against the first lower pressure ring 22. The cone sleeve 31 has an inner conical surface 311 with a diameter gradually expanding downward, and the outer wall of the slip 32 is an outer conical surface 322 matched with the inner conical surface 311. The slip 32 is inserted into the cone sleeve 31 in a contracted state. The upper outer wall of the pipe 33 is threadedly connected to the lower inner wall of the cable channel 141, and the upper end of the pipe 33 can be pressed against the slip 32.

[0045] The purpose of limited sealing can be achieved by pressing the slip 32 and the first sealing rubber tube 2 together through the threaded cooperation between the pipe 33 and the cable channel 141. Generally, the first sealing rubber tube 2 can adopt a waist-shaped structure, for example Figure 4As shown in the figure, two planes 20 are symmetrically cut on the cylindrical rubber cylinder body, and the part of the cable channel 141 that cooperates with it also adopts the same shape to prevent the first sealing rubber cylinder 2 from rotating and causing the connecting pipe 33 to be detached.

[0046] In order to make the slips 32 radially contract smoothly, Figure 6 and Figure 7 As shown, the slip 32 is a conical tube body with a longitudinal cutout 323, teeth 321 are formed on the inner wall of the conical tube body, and an outer conical surface 322 is formed on the outer wall of the conical tube body. A plurality of slits 324 are formed on the tube wall of the conical tube body, and the slits 324 extend to one end of the conical tube body. Due to the presence of the longitudinal cutout 323 and the plurality of slits 324, the slip 32 forms a multi-petal structure with gaps between each petal, so that the conical tube body has a certain elasticity, and the overall radial contraction or expansion of the slip 32 can be achieved by changing the width of the longitudinal cutout 323 and the gap width of the slits 324.

[0047] More specifically, the taper of the outer conical surface 322 of the slip 32 and the inner conical surface 311 of the cone sleeve 31 should be the same, and the two can fit each other when in use. At the same time, when the outer conical surface 322 of the slip 32 and the inner conical surface 311 of the cone sleeve 31 are naturally fitted (that is, the slip 32 is in a state of natural expansion and no radial contraction), there should be a certain distance (referred to as the first distance) between the upper end of the slip 32 and the first lower pressure ring 22; when the connecting pipe 33 just fits with the slip 32 during the process of screwing into the cable channel 141, there should also be a certain distance (referred to as the second distance) between the thread step of the connecting pipe 33 (specifically, the lowest end of its thread step) and the bottom end of the cable channel 141, and the second distance should be greater than the first distance.

[0048] When the connecting pipe 33 continues to be screwed in, the cava 32 will move upward. On the one hand, the cava 32 pushes the first lower pressure ring 22 and the first sealing rubber tube 2 upward, and the first sealing rubber tube 2 is axially compressed and radially expanded, so that it can be tightly attached to the built-in cable to ensure the sealing performance; on the other hand, during the upward movement of the cava 32, since the diameter of the inner conical surface 311 gradually decreases upward, each petal of the cava 32 will be compressed, so that the cava 32 is in a contracted state, and the distance between the tooth tips of the opposite side teeth 321 in the cava 32 is reduced. When the distance is reduced to less than the outer diameter of the armor tube of the armored cable, the tooth tips of the teeth 321 of the cava 32 will bite into the armor tube of the cable and tighten it, so that the armored cable cannot move, thereby achieving the fixation of the cable.

[0049] Therefore, the entire slip connector 3 is connected by the cone sleeve 31, slip 32 and pipe 33. The slip 32 can be pushed to move by continuously tightening the pipe 33. The slip 32 is used to push the first lower pressure ring 22 and the first sealing rubber tube 2 to achieve the sealing of the built-in cable. The tightening of the pipe 33 and the inner conical surface 311 of the cone sleeve 31 can drive the contraction of the slip 32, thereby biting the armor tube of the built-in cable. The biting effect of the teeth 321 on the slip 32 can ensure that the built-in cable is fixed and suspended reliably regardless of whether it is subjected to upward or downward forces. Moreover, when the built-in cable is subjected to an upward pulling force, the slip 32 will be pulled to move upward along the inner conical surface 311, which will make the bite tighter and tighter. On the one hand, the built-in cable is fixed underground. On the other hand, the biting of the slip 32 can make the built-in cable withstand greater pulling force, ensuring the stable suspension of the built-in cable underground.

[0050] In practical applications, in order to further improve the suspension effect of built-in cables, such as Figure 6 As shown, the plurality of slits 324 include a plurality of first slits 3241 and a plurality of second slits 3242 arranged in a staggered manner, the first slits 3241 extend upward to the upper end of the tapered tube body, and the second slits 3242 extend downward to the lower end of the tapered tube body. In the process of the pipe 33 being screwed in and driving the slip 32 to contract, the staggered first slits 3241 and the second slits 3242 can make the contraction deformation of the slip 32 more uniform, and the teeth 321 in the slip 32 can bite the built-in cable more uniformly, avoiding the situation where some teeth 321 bite tightly while some teeth 321 bite loosely, so that the slip 32 can fix the built-in cable more firmly.

[0051] Further preferably, the upper end of the connecting pipe 33 is circumferentially fixedly connected to the lower end of the slip 32 .

[0052] The circumferential fixation of the pipe 33 and the slip 32 can be achieved in this way: a plurality of grooves are provided at intervals in the circumferential direction on the lower end surface of the slip 32, and a plurality of protrusions are provided at intervals in the circumferential direction on the upper end of the pipe 33. The shape of the protrusions matches the shape of the grooves, and the protrusions can be embedded in the grooves. When the protrusions are locked in the grooves, the lower pipe 33 and the slip 32 are circumferentially fixed, and the slip 32 can rotate when the pipe 33 is screwed in; if the cable has a tendency to rotate during subsequent construction and production operations, the torque generated by the slip 32 can be borne by the pipe 33 and its meshing threads through the cooperation of the grooves and the protrusions, which can effectively prevent the internal cable from being twisted and damaged.

[0053] Furthermore, if Figure 3As shown, an upper limit step 142 and a lower limit step 143 are formed on the inner wall of the cable channel 141, and the first upper pressure ring 21 can lean against the upper limit step 142 to limit the axial position of the first upper pressure ring 21; a limit ring 221 is protruded outwardly from the lower part of the first lower pressure ring 22, and the lower limit step 143 is located above the limit ring 221 and can limit the axial position of the limit ring 221. When the first sealing rubber tube 2 is not axially compressed, a certain distance should be left between the limit ring 221 and the lower limit step 143. When the first sealing rubber tube 2 is axially compressed, the distance gradually decreases. The setting of the lower limit step 143 can limit the upper limit position of the first lower pressure ring 22, avoid the first sealing rubber tube 2 from being excessively compressed, and play a certain protective role for the first sealing rubber tube 2.

[0054] The above-mentioned internal cable can directly pass through the outer pipe 1 after passing through the lower end of the cable channel 141, and dock with the lead-in cable of the electric submersible pump in the oil casing annulus. However, in this way, the docking position of the internal cable and the lead-in cable is exposed in the oil casing annulus, which is easy to cause damage. In order to protect the docking position of the two in this embodiment, in a preferred embodiment, Figure 1 and Figure 2 As shown, an installation cavity 13 is also provided in the outer tube 1, and an opening is provided at a position of the tube wall of the outer tube 1 corresponding to the installation cavity 13, and a gland 131 is sealed and connected at the opening. A limit tube 14 is sealed and fixed in the installation cavity 13, and the inner diameter of the limit tube 14 constitutes a cable channel 141. A notch 16 is provided in the lower outer side wall of the outer tube 1, and the lower end of the installation cavity 13 is connected to the notch 16 through an oblique channel 15. The lead-in cable of the submersible pump can pass through the oblique channel 15 in a sealed manner, and the built-in cable and the lead-in cable can be connected in the installation cavity 13.

[0055] Among them, the upper part of the oil passage 12 is arranged side by side with the entire installation cavity 13, and the cable channel 141 is located in the installation cavity 13. The oblique channel 15 is opened in the outer tube 1, and there is a certain angle between the axis of the oblique channel 15 and the axis of the outer tube 1. The inner diameter of the upper end of the limit tube 14 and the inner diameter of the connecting pipe 33 should be slightly larger than the armor tube size of the armored cable. The upper limit step 142 and the lower limit step 143 are specifically formed on the inner wall of the limit tube 14. The upper part of the limit tube 14 has two stepped holes with increasing apertures downward, and the shoulders of the two stepped holes constitute the upper limit step 142 and the lower limit step 143 respectively.

[0056] During installation, after the built-in cable passes through the main channel 11 and the cable channel 141 in sequence and passes out of the cable channel 141, the lead cable of the electric submersible pump is passed through the oblique channel 15 into the installation cavity 13, the built-in cable and the lead cable are connected in the installation cavity 13, and then the gland 131 is covered. In this way, the first sealing rubber cylinder 2 and the slip connector 3 in the cable channel 141 are used to realize the stable suspension of the built-in cable and the sealing of the built-in cable when passing through the cable channel 141, and the sealing function of the oblique channel 15 ensures the sealing of the lead cable when passing through the oblique channel 15. The built-in cable and the lead cable are connected in the installation cavity 13 and sealed by the gland 131, which effectively prevents the oil sleeve ring air liquid from entering the outer tube 1 during use, and the docking position of the built-in cable and the lead cable is also effectively protected, avoiding damage to the docking position, and improving the service life as well as the safety and efficiency of the operation.

[0057] Preferably, the above-mentioned installation cavity 13 is a grease injection cavity, in which electrical insulating resin can be injected to achieve an insulating sealing effect. The hollow area in the installation cavity 13 can be completely filled with electrical insulating resin, which effectively prevents the entry of air and liquid into the oil sleeve ring, further improves the sealing performance, and makes the sealing more reliable. It can be understood that a grease injection hole will be opened on the gland 131. After the built-in cable and the lead cable are connected, the gland 131 is sealed and connected at the opening, and electrical insulating resin is injected into the grease injection cavity through the grease injection hole. Finally, a plug can be installed at the grease injection hole. The specific grease injection process is a prior art and will not be repeated here.

[0058] Generally, in order to facilitate the installation of the limiting tube 14, the upper end of the installation cavity 13 has a mounting hole 132, the upper end of the limiting tube 14 is threadedly connected to the mounting hole 132, and a sealing ring is sandwiched between the limiting tube 14 and the mounting hole 132. The mounting hole 132 is specifically formed in the outer tube 1 and communicates with the main channel 11 and the installation cavity 13.

[0059] Furthermore, in order to ensure the sealing of the lead cable when it passes through the outer tube 1, Figure 1 As shown, a stepped hole 151 with an increased aperture is formed downwardly at the lower portion of the oblique channel 15, and a second upper pressure ring 41, a second sealing rubber tube 4, a second lower pressure ring 42 and a hollow bolt 5 are sequentially embedded in the stepped hole 151 from top to bottom. The hollow bolt 5 is threadedly connected to the hole wall of the stepped hole 151, and the hollow bolt 5 can rest against the second lower pressure ring 42.

[0060] The stepped hole 151 extends downward to the bottom end of the oblique channel 15, and the top shoulder of the stepped hole 151 can limit the second upper pressure ring 41. There is an internal thread at the end of the stepped hole 151. The second sealing rubber tube 4 is sandwiched between the second upper pressure ring 41 and the second lower pressure ring 42. The outermost hollow bolt 5 has internal through holes passing through both ends thereof. The inner diameters of the second sealing rubber tube 4, the two pressure rings and the hollow bolt 5 should match the outer diameter of the armor tube of the armored cable. The front end external thread of the hollow bolt 5 can be connected with the end internal thread of the stepped hole 151, and the bolt head of the hollow bolt 5 is exposed to the outside. When the hollow bolt 5 is rotated to just contact the second lower pressure ring 42, the thread step of the hollow bolt 5 (specifically refers to the lowest end of its thread step, that is, the upper end position of the bolt head) should be at a certain distance from the stepped hole opening (that is, the lower end of the oblique channel 15), so that the hollow bolt 5 can continue to be screwed in to compress the radial expansion of the second sealing rubber tube 4, thereby sealing the annulus between the armor tube and the stepped hole 151.

[0061] Through the cooperation of the second upper pressure ring 41, the second lower pressure ring 42, the second sealing rubber tube 4 and the hollow bolt 5, when the hollow bolt 5 is continuously screwed inward, the second sealing rubber tube 4 is radially deformed under the extrusion of the second lower pressure ring 42, and plays the role of sealing the annulus between the cable armor tube and the stepped hole 151, effectively ensuring the sealing of the lead-in cable outlet end and preventing the oil casing annulus liquid from entering the tool. The upper part of the stepped hole 151 (i.e., the unthreaded part) and the second upper pressure ring 41, the second lower pressure ring 42 and the second sealing rubber tube 4 matched therewith are generally not in the shape of a perfect circle, so as to prevent the sealing assembly composed of the pressure ring and the second sealing rubber tube 4 from rotating during use, affecting the sealing effect.

[0062] The above-mentioned oblique channel 15 adopts an oblique design. Because the cable is coated with a few millimeters thick armor layer on the outside, it is difficult to bend. If the bending angle is too large, there is a risk of cable damage. The use of the oblique channel 15 with an oblique design allows the cable to be smoothly inserted into the installation cavity 13 without other internal docking links. Due to the bending of the armored cable product itself and considering the crossing distance, the angle between the axis of the oblique channel 15 and the axis of the outer tube 1 is preferably 5 to 10 degrees to facilitate the natural crossing of the lead cable.

[0063] Preferably, the cross section of the notch 16 in the plane where the axis of the oil passage 12 and the axis of the oblique passage 15 are located is a trapezoid, and the lower bottom of the trapezoid corresponds to the open end of the notch 16, and the two waists of the trapezoid are both hypotenuses, and one of the hypotenuses (i.e., the upper hypotenuse) is connected to the lower end of the oblique passage 15 and is perpendicular to the axis of the oblique passage 15. The two hypotenuses of the trapezoid correspond to the upper and lower oblique surfaces of the notch 16, and the two oblique surfaces of the notch 16 can facilitate the smooth entry of the lead cable into the installation cavity 13 and connect with the built-in cable. Generally, the angle between the upper hypotenuse of the trapezoid and the horizontal plane and the angle between the lower hypotenuse of the trapezoid and the axis of the outer tube 1 should be as small as possible, so that the lead cable can smoothly enter the installation cavity 13 and avoid the cable from being damaged by large bending. In this embodiment, because the upper hypotenuse of the trapezoid is perpendicular to the axis of the oblique passage 15, the angle between the upper hypotenuse of the trapezoid and the horizontal plane 20 is equal to the angle between the axis of the oblique passage 15 and the axis of the outer tube 1, and both are preferably 5 to 10°. The angle between the hypotenuse (ie, the lower hypotenuse) in the trapezoid away from the oblique channel 15 and the axis of the outer tube 1 is less than or equal to 30°.

[0064] In order to facilitate processing and installation, Figure 2 As shown, the outer tube 1 comprises an upper tube body 17, an intermediate tube body 18 and a lower tube body 19 which are sequentially sealed and connected from top to bottom, the main channel 11 is formed in the upper tube body 17, the mounting cavity 13 and the oblique channel 15 are formed in the intermediate tube body 18. A part of the oil passage 12 is formed in the intermediate tube body 18, and another part of the oil passage 12 is formed in the lower tube body 19. The opening is provided on the intermediate tube body 18, a part of the notch 16 is formed on the outer wall of the intermediate tube body 18, and another part is formed on the outer wall of the lower tube body 19.

[0065] The entire outer tube 1 constitutes an eccentric structure, which is divided into two parts below the main channel 11, and is provided with an oil passage 12 and a cable passage 141, which do not interfere with each other. The cable passage 141 is used to pass the built-in cable, and the second sealing rubber tube 4 and the slip connector 3 in the limiting tube 14 are used to seal and limit the armored cable. Generally, the lower end outer wall of the upper tube body 17 is threadedly connected to the upper end inner wall of the intermediate tube body 18, and the lower end inner wall of the intermediate tube body 18 is threadedly connected to the upper end outer wall of the lower tube body 19. There are grooves at each connection to add a sealing ring to achieve the purpose of sealing, so as to prevent leakage between the inner cavity of the outer tube 1 and the external liquid. The upper end of the upper tube body 17 is an inner thread of the oil pipe, which can be connected to the downhole tool string, and the lower end of the lower tube body 19 is an outer thread of the oil pipe, which can be connected to the tool string at the lower end. In order to facilitate processing, the oil passage 12 includes an axial passage 121 and an inclined passage 122 that are interconnected, the axis of the axial passage 121 is parallel to the axis of the outer tube 1, the axis of the inclined passage 122 is arranged at a certain angle to the axis of the axial passage 121, and the lower end of the inclined passage 122 is connected to the lower end center of the lower tube body 19. The axial passage 121 is located in the middle tube body 18 and arranged side by side with the mounting cavity 13, and the inclined passage 122 is located in the lower tube body 19.

[0066] Furthermore, the installation method of the above-mentioned steel coiled pipe built-in cable downhole connection short section is as follows:

[0067] The built-in cable is passed through the continuous tubing along the inner channel of the downhole tool string until it reaches the downhole connecting short section in this embodiment. Specifically, a suitable abandoned well is selected, and the continuous tubing vehicle is used to lower the continuous tubing into the casing of a vertical well of suitable depth. The continuous tubing should be kept vertical as much as possible, and the upper end of the continuous tubing is slightly exposed from the injection head and kept vertical. The injection head is fixed after the wellhead device is connected to the blowout preventer; the pulley is lifted by a crane and placed above the continuous tubing, and the staff passes the built-in cable through the pulley and vertically introduces it into the continuous tubing. Generally, an armored cable greater than the design depth of 5-10m is invested in the continuous tubing to increase the surplus volume and facilitate the insertion of later tools. The continuous tubing used can be the retired continuous tubing after fracturing, which rationally utilizes waste resources and greatly reduces production costs.

[0068] When installing the downhole connection nipple, first seal and connect the upper pipe body 17, the middle pipe body 18 and the lower pipe body 19, and connect the stop pipe 14 with the middle pipe body 18 through threaded matching, then pass the built-in cable through the assembled outer pipe 1, and then pass the built-in cable through the main channel 11 and the cable channel 141 in turn, and connect the upper end of the upper pipe body 17 with the downhole tool string after passing through a suitable distance. Then, pass the built-in cable through the first upper pressure ring 21, the first sealing rubber tube 2, the first lower pressure ring 22, the cone sleeve 31, the slip 32 and the pipe 33 in turn, and push these parts into the stop pipe 14, connect the external thread of the pipe 33 with the internal thread at the lower end of the stop pipe 14, and after the pipe 33 is completely tightened, the built-in cable is sealed by the first sealing rubber tube 2, and is tightly bitten by the slip 32 and will not move. Since the mating surface between the cava 32 and the cone sleeve 31 is a cone, when the built-in cable and the tool string are to move relative to each other, the cava 32 will be pressed tighter by the cone, and the built-in cable will be bitten tighter, ensuring the stable suspension and fixation of the built-in cable underground, and the first sealing rubber cylinder 2 will also be sealed more reliably.

[0069] Next, the lead-in cable of the electric submersible pump is passed through the hollow bolt 5, the second lower pressure ring 42, the second sealing rubber tube 4 and the second upper pressure ring 41 in sequence, and then passed into the installation cavity 13 through the oblique channel 15. Then, these four parts are placed in the oblique channel 15 in sequence, and the hollow bolt 5 is screwed in. During the screwing-in process, the hollow bolt 5 pushes the second lower pressure ring 42, and the second sealing rubber tube 4 is pressed to deform by pushing the second lower pressure ring 42, thereby sealing the annular space between the lead-in cable and the oblique channel 15.

[0070] The built-in cable is connected to the lead-in cable in the installation cavity 13. After the connection is completed, the pressure cover 131 is covered, and then 3M electrical insulating resin is injected into the installation cavity 13. The installation of the downhole connection short section of this embodiment is completed.

[0071] In summary, the downhole connection sub in this embodiment has the following advantages:

[0072] (1) In the process of oil production, the cable is a device for conducting signals between downhole instruments and uphole equipment. However, due to the particularity of the downhole environment and the inherent conditions in oil production, the cable will generate certain vibrations, which may cause the cable connection to loosen or break, resulting in the project having to be interrupted, thereby causing high maintenance costs and downtime costs. In this embodiment, through the cooperation of the cone sleeve 31, the slip 32 and the pipe 33 in the slip connector 3, the slip 32 and the cone sleeve 31 have conical surfaces, which cooperate with each other to grasp the outer armor layer of the armored cable through the wedging action of the slip 32, so as to achieve a firm suspension of the built-in cable. By using the slip connector 3 to accurately fix the position of the armored cable, on the one hand, the slip 32 can fix the armored cable, and on the other hand, the completion tool can withstand a load of less than 8T when going down the well, effectively avoiding signal connection interruption caused by external vibration.

[0073] (2) Common underwater cable insulation protection methods include lead seal insulation protection, heat shrink tubing protection, mechanical sealing, etc. However, these three methods have little effect in a 3000-meter downhole pressure difference environment of 3MPa. In this embodiment, by setting the first sealing rubber tube 2 in the limit tube 14, the threaded cooperation of the connecting pipe 33 and the limit tube 14 can provide a force for the movement of the slip 32 and the deformation of the first sealing rubber tube 2. The first sealing rubber tube 2 itself is squeezed and expanded by force, and the sealing of the built-in cable can be completed. By setting the second sealing rubber tube 4 and tightening the hollow bolt 5 to squeeze and expand it, the sealing of the lead cable can be completed. The two-stage sealing rubber tube is used for simultaneous sealing, which can protect the cable from wear and reduce the friction resistance of the liquid flow in the channel while realizing the cable-controlled intelligent oil production of power transmission and signal communication, thereby improving the reliability of the cable-controlled oil production system and effectively solving the sealing problem.

[0074] (3) After the built-in cable and the lead cable are connected in the installation cavity 13, electrical insulation resin is injected into the installation cavity 13 to achieve an overall insulation sealing effect. The sealing measures of the first sealing rubber tube 2, the second sealing rubber tube 4 and the electrical insulation resin are more reliable, effectively preventing the oil sleeve ring air liquid from entering the outer tube 1. In addition, the built-in cable and the lead cable are connected in the installation cavity 13 and the insulation seal is achieved by the electrical insulation resin, which effectively protects the connection position of the two and prolongs the service life.

[0075] (4) The fixing and sealing of the built-in cable adopts a split embedded structure, which does not affect the main flow path. The connection between the limit tube 14 and the intermediate tube body 18 adopts a threaded connection, which enhances the adaptability of on-site connection. It can achieve repeated sealing of the cable, enhance the adaptability to complex working conditions and the convenience of operation. The flow cross-sectional area of ​​the oil passage 12 is the same as the flow cross-sectional area of ​​the steel coiled tube, which ensures the flow path of the tool.

[0076] The entire downhole connection nipple can effectively protect the cable from being squeezed or eroded, avoid cable damage during oilfield mining operations, improve the reliability of downhole cable connections, simplify the operation process, improve the efficiency of construction operations and maintenance of well equipment, reduce production costs, and solve the problems of high cost, low efficiency, and long cycle in traditional mining operations. In addition to being suitable for conventional continuous pipe operations, it is particularly suitable for the application of complex downhole live (electric submersible pumps, etc.) processes, which can significantly reduce construction complexity and improve operating efficiency.

[0077] The above are only exemplary embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A steel coiled tubing built-in cable downhole connection nipple, characterized in that: Including outer tube; The outer tube has a main channel, an oil passage channel and a cable channel, the main channel is connected to the upper end of the outer tube, the oil passage channel and the cable channel are both connected to the main channel, the axes of the oil passage channel and the cable channel are both deviated from the center line of the main channel, and the lower part of the oil passage channel is connected to the center of the lower end of the outer tube after being deflected, and the cable channel can allow the built-in cable to pass through; A first sealing rubber tube and a slip connector are provided in the cable channel, and the built-in cable can pass through the first sealing rubber tube and the slip connector in sequence. The first sealing rubber tube is arranged in an axially compressed state and can be sealed against the built-in cable. The slip connector has a slip that can be radially contracted and has teeth on the inner wall. The slip is arranged in a contracted state and the teeth can bite the built-in cable. A first upper pressure ring and a first lower pressure ring are respectively provided at both ends of the first sealing rubber cylinder, and the first upper pressure ring is axially limited at the upper part of the cable channel; the cava connector also includes a tapered sleeve and a connecting pipe, and the tapered sleeve can be abutted against the first lower pressure ring; the tapered sleeve has an inner conical surface with a diameter gradually expanding downward, and the outer wall of the cava is an outer conical surface matching the inner conical surface, and the cava is inserted into the tapered sleeve in a contracted state; the outer wall of the upper end of the connecting pipe is threadedly connected to the inner wall of the lower end of the cable channel, and the upper end of the connecting pipe can be abutted against the cava; the cava is a conical tube body with a longitudinal incision, the teeth are formed on the inner wall of the conical tube body, and the outer conical surface is formed on the outer wall of the conical tube body; a plurality of slits are formed on the tube wall of the conical tube body, and the slits extend to one of the ends of the conical tube body.

2. The steel coiled tube built-in cable downhole connection nipple according to claim 1, characterized in that: The flow cross-sectional area of ​​the oil passage is the same as the flow cross-sectional area of ​​the steel coiled pipe.

3. The steel coiled tubing built-in cable downhole connection nipple according to claim 1, characterized in that: The plurality of slits include a plurality of first slits and a plurality of second slits that are staggered, the first slits extend upward to the upper end of the conical tube body, and the second slits extend downward to the lower end of the conical tube body.

4. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 1, characterized in that: The upper end of the connecting pipe is circumferentially fixedly connected to the lower end of the slip.

5. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 1, characterized in that: An upper limit step and a lower limit step are formed on the inner wall of the cable channel, the first upper pressure ring can lean against the upper limit step, a limit ring is protruded outwardly from the lower part of the first lower pressure ring, the lower limit step is located above the limit ring and can limit the axial position of the limit ring.

6. The steel coiled tubing built-in cable downhole connection nipple according to claim 1, characterized in that: The outer tube is also provided with an installation cavity, an opening is provided at a position of the tube wall of the outer tube corresponding to the installation cavity, and a gland is sealed and connected at the opening; a limiting tube is sealed and fixed in the installation cavity, and the inner diameter of the limiting tube constitutes the cable channel; A notch is provided on the lower outer side wall of the outer tube, and the lower end of the installation cavity is connected to the notch through an oblique channel. A lead-in cable for supplying an electric submersible pump can pass through the oblique channel in a sealed manner, and the built-in cable and the lead-in cable can be connected in the installation cavity.

7. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 6, characterized in that: The installation cavity is a grease injection cavity, into which electrical insulating resin can be injected.

8. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 6, characterized in that: The upper end of the installation cavity is provided with an installation hole, the upper end of the position limiting tube is threadedly connected to the installation hole, and a sealing ring is sandwiched between the position limiting tube and the installation hole.

9. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 6, characterized in that: A stepped hole with an increasing aperture is formed downwardly at the lower portion of the oblique channel, and a second upper pressure ring, a second sealing rubber tube, a second lower pressure ring and a hollow bolt are sequentially embedded in the stepped hole from top to bottom. The hollow bolt is threadedly connected to the hole wall of the stepped hole, and the hollow bolt can lean against the second lower pressure ring.

10. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 6, characterized in that: The cross-section of the notch in the plane where the axis of the oil passage and the axis of the oblique channel are located is a trapezoid, and the lower base of the trapezoid corresponds to the opening end of the notch, and the two waists of the trapezoid are both hypotenuses, and one of the hypotenuses is connected to the lower end of the oblique channel and is perpendicular to the axis of the oblique channel.

11. The steel coiled tubing built-in cable downhole connection nipple as claimed in claim 10, characterized in that: The angle between the axis of the oblique channel and the axis of the outer tube is 5-10°, and the angle between the hypotenuse in the trapezoid away from the oblique channel and the axis of the outer tube is less than or equal to 30°.

12. The steel coiled tubing built-in cable downhole connection nipple according to claim 6, characterized in that: The outer tube includes an upper tube body, an intermediate tube body and a lower tube body which are sealed and connected in sequence from top to bottom, the main channel is formed in the upper tube body, the mounting cavity and the oblique channel are formed in the intermediate tube body; a part of the oil passage is formed in the intermediate tube body, and another part of the oil passage is formed in the lower tube body; the opening is opened on the intermediate tube body, a part of the notch is formed on the outer wall of the intermediate tube body, and another part is formed on the outer wall of the lower tube body.

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