Toothed intermeshing switchable oil well completion plug

Abstract

The present application belongs to the technical field of oil and gas well downhole operation, and particularly relates to a tooth-shaped staggered switch type oil well completion plug, aiming at solving the problem that there is no completion tool capable of repeatedly and reliably controlling the communication and plugging of the whole wellbore in the prior art. The present application provides a tooth-shaped staggered switch type oil well completion plug, which comprises a sand blocking pipe, an anchoring plug, an emergency valve, a tooth-shaped staggered valve and a sand setting pipe connected in sequence. The opening or closing action of the tooth-shaped staggered structure is completed through the pressurization and pressure relief of the wellhead, the repeated and reliable opening and closing action of the well bottom is realized, the communication and plugging of the whole wellbore are completed, the reliability of the component activity is strengthened through the combined action of the sand blocking pipe and the sand setting pipe, the 100% opening of the wellbore is realized through the setting of the emergency structure design and the anchor plug design capable of being fished and triggered, and the 100% full bore of the wellbore in subsequent operations is ensured in necessary cases, so that the completion operation is ensured to be carried out smoothly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of downhole operation of oil and gas well, and particularly relates to a tooth-shaped staggered switch type oil well completion plug. BACKGROUND

[0002] Before the pump is put into production or the pump is repaired during the production process after the oil and gas layer of the oil well is opened, the general practice is to use well killing fluid to balance the formation pressure to ensure the safety of well control under the condition of well control, and then the completion operation is performed. The use of well killing fluid has two problems: one is that it pollutes the reservoir and affects the production, and the other is that it increases the cost input. At present, the oil well completion operation is performed without well killing, which is generally divided into three types: one is an internal control valve for non-well killing operation, which needs to be transmitted through the oil pipe and used on the oil pipe, and the opening and closing action is realized by pressing in the oil pipe, but it cannot be released, and cannot realize the connection and sealing of the whole wellbore in the casing, and is not suitable for the oil production operation such as pump lowering and pump repair after completion. Moreover, this opening and closing action valve relies on the long and short tracks in the tool to realize the action, and the reliability is low, and it often cannot be closed after being opened, or cannot be opened after being closed, and cannot be directly applied to the non-well killing operation of the whole wellbore. The second is a pressure operation device for non-well killing operation, including a coiled tubing operation device, which completes the operation of lowering the pipe string through the cooperation of the blowout preventer or the blowout preventer group, but if a large-diameter tool or an electric submersible pump with a cable is connected to the pipe string, the sealing cannot be realized through the rubber of the blowout preventer, resulting in the failure of the pressure operation. The third is a temporary plug for non-well killing operation, which is divided into a pressurized opening type and a soluble type. The pressurized opening type temporary plug is released after being lowered into the well through the oil pipe, and the temporary plug is set in the well, and after the pump or other wellbore operation is completed, the temporary plug is opened by pressing at the wellhead to form an oil flow channel. The soluble type temporary plug can be dissolved within a certain time after the wellbore operation is completed to form an oil flow channel. The problems of these two types of temporary plugs are that the tool is used once and cannot be repeatedly opened and closed, that is, after a period of production, if the wellbore operation such as pump repair is performed, well killing still needs to be performed, which causes damage to the production layer. Therefore, the tool is only suitable for non-well killing operation of new wells. At present, there is no completion tool that can repeatedly and reliably control the connection and sealing of the whole wellbore. SUMMARY

[0003] In order to solve the above-mentioned problems in the prior art, that is, in order to solve the problem that there is no completion tool that can repeatedly and reliably control the connection and sealing of the whole wellbore in the prior art, the present application provides a tooth-shaped staggered switch type oil well completion plug, which comprises a sand blocking pipe, an anchor plug, an emergency valve, a tooth-shaped staggered valve and a sand setting pipe connected in sequence, fluid can enter the sand setting pipe and be transported to the sand blocking pipe through the fluid passages of the tooth-shaped staggered valve, the emergency valve and the anchor plug in sequence, and be output from the oil production hole of the side wall of the sand blocking pipe; the fluid passage is composed of the first, second and third prefabricated holes respectively arranged on the anchor plug, the emergency valve and the tooth-shaped staggered valve.

[0004] The sand-blocking pipe is used to prevent solid impurities from settling into the well completion plug;

[0005] The anchoring plug includes slips for fitting against the inner wall of the well to suspend the completion plug;

[0006] The emergency valve contains a corrosive liquid that can be sprayed out under external force to corrode the slip and release the anchor plug.

[0007] The toothed interlaced valve is used to open or close the fluid passage;

[0008] The settling pipe is used for fluid entry and settling of solid impurities.

[0009] In some preferred technical solutions, the outer diameter of the sand-blocking pipe is smaller than the outer diameter of the anchoring plug, the end of the sand-blocking pipe away from the anchoring plug is sealed, and a number of oil production holes are evenly distributed along the circumference of the side wall of the sand-blocking pipe, with the opening direction of the oil production holes inclined upward.

[0010] In some preferred embodiments, the outer surface of the swivel is coated with a non-degradable coating, the interior of the swivel is made of a degradable material, and the non-degradable coating can be corroded by the corrosive liquid.

[0011] In some preferred technical solutions, the emergency valve includes a valve body, an inner plug, and an X valve. The valve body is a cylindrical structure with stepped through holes inside. The diameter of the holes at the upper part of the valve body is larger than the diameter of the holes at the lower part of the valve body. A number of even-numbered single-flow holes are evenly distributed along the circumference at the upper part of the valve body, and a single-flow ball is disposed in each single-flow hole.

[0012] The inner plug includes a first structural part and a second structural part arranged vertically. The first structural part matches the upper aperture of the valve body, and the second structural part matches the lower aperture of the valve body. The inner plug has a second pre-made hole in the middle. The inner plug is fixed in the upper aperture of the valve body by a pin.

[0013] The height of the first structural part is less than the distance from the lower edge of the single flow orifice to the step surface of the stepped through hole of the valve body, and the height of the second structural part is less than the distance from the step surface of the stepped through hole of the valve body to the lower end face. In the initial state, the inner plug blocks the single flow orifice.

[0014] In some preferred technical solutions, an acid chamber is provided at the bottom of the valve body, an acid bladder is provided in the acid chamber, an acid hole is provided between any two adjacent single flow holes, a number of acid holes are evenly distributed around the circumference of the valve body and the acid hole outlet is inclined upward, the acid hole is vertically arranged and a rupture disc is horizontally installed in the middle, and the bottom of the acid hole is connected to the top of the acid chamber.

[0015] The valve body is also provided with X-valve holes, and a number of even-numbered X-valve holes are in the same position as the single flow orifice and are evenly distributed circumferentially on the lower end face of the valve body; the bottom of the acid chamber is connected to the X-valve holes, and an X-shaped spring plate and a steel ball are provided inside the X-valve holes. Both the X-valve and the inner plug are opened by wellhead pressure. The opening pressure of the X-valve is greater than the opening pressure of the inner plug, and the bursting pressure of the rupture disc is between the opening pressure of the X-valve and the opening pressure of the inner plug.

[0016] In some preferred embodiments, a nozzle is installed at the outlet of the acid orifice; the inner flow channel of the nozzle is conical, and the nozzle is made of a material resistant to acid corrosion.

[0017] In some preferred embodiments, the toothed interlaced valve includes an outer cylinder, an upstream toothed valve, a downstream toothed valve, a central tube, and an elastic element; the upstream toothed valve, the downstream toothed valve, the central tube, and the elastic element are all installed inside the outer cylinder;

[0018] The outer cylinder is a stepped tubular structure, which includes a first tubular structure and a second tubular structure arranged vertically. The wall thickness of the first tubular structure is greater than that of the second tubular structure. An even number of fixed teeth are arranged circumferentially on the inner wall of the first tubular structure. The fixed teeth include tooth-shaped parts and tooth groove parts. The tooth-shaped parts are used to limit the movement range of the downstream tooth valve, and the tooth groove parts are used to limit the movement range of the upstream tooth valve.

[0019] The bottom of the central tube is sealed and detachably installed at the bottom of the outer cylinder. The central tube has an oil inlet hole in its circumference and several oil outlet holes are evenly distributed along the circumference of the middle sidewall of the central tube.

[0020] The upstream toothed valve includes an outer cylinder and a central cylinder. The outer cylinder is fitted over the central cylinder. The outer cylinder has a radially contracted inner portion forming an annular protrusion. The top of the central cylinder is connected to the outer cylinder through the annular protrusion. The central cylinder and the outer cylinder are coaxially arranged. The inner diameter of the annular protrusion is smaller than the inner diameter of the central cylinder. The outer diameter of the outer cylinder matches the inner diameter of the first tubular structure. The outer diameter of the central cylinder matches the inner diameter of the downstream toothed valve. The inner diameter of the central cylinder matches the outer diameter of the central tube. The lower end face of the outer cylinder is cut with upstream teeth. The number of upstream teeth is the same as the number of fixed teeth. The inclination angle and thickness of the upstream teeth are the same as the inclination angle and thickness of the fixed teeth. A fixed wedge is fixed in the vertical direction of the tooth tip of the upstream teeth. The width of the fixed wedge matches the tooth groove portion.

[0021] The downstream toothed valve has downstream teeth cut at its upper end. The number of downstream teeth is half the number of upstream teeth. The inclination angle and thickness of the downstream teeth are the same as those of the upstream teeth. The downstream teeth can mesh with the fixed teeth and the upstream teeth. The bottom outer edge of the downstream toothed valve matches the inner diameter of the second tubular structure. The downstream toothed valve is used to convert linear motion into rotational motion.

[0022] The elastic element is sleeved outside the central tube, and the bottom of the elastic element abuts against the upper surface of the bottom of the outer cylinder. The elastic element is used to provide a rebound force for the downstream toothed valve.

[0023] The annular space between the outer cylinder and the central tube forms a sealing structure, and the up-and-down movement of the sealing structure can open or close the oil drain hole on the central tube.

[0024] In some preferred embodiments, the toothed interlaced valve further includes a directional valve, which is installed at the top of the upstream toothed valve. The directional valve includes a valve block and a directional valve body. The side wall of the directional valve body has a fluid passage hole. The valve block is frustoconical and is operably installed at the bottom of the directional valve body. The top surface of the valve block is fixed by a tension spring. The bottom surface of the valve block matches the bottom of the directional valve body. The diameter of the bottom surface of the valve block is larger than the diameter of the constriction at the center hole of the upstream toothed valve. The valve block can seal the constriction.

[0025] In some preferred embodiments, the height of the toothed portion is greater than the height of the upstream tooth and the downstream tooth.

[0026] In some preferred technical solutions, the bottom of the sand settling pipe is a spherical head, and several flow channel holes are evenly distributed circumferentially on the upper part of the side wall of the sand settling pipe. A conical baffle is provided inside the upper end of the sand settling pipe, and the upper surface of the conical baffle is located above the flow channel holes, while the lower end face is a circular hole.

[0027] The beneficial effects of this invention are:

[0028] The toothed, interlaced, switchable well completion plug of this invention enables wellbore operation without pressure, including operation with various downhole tools such as production pumps and maintenance pumps. It is not limited by the tools themselves or the production formation. The pressure applied to the wellhead can be determined by adjusting the elastic force of the elastic element according to the pressure of the production formation, thus matching the pressure with the production formation pressure. This tool completes the action of pressurization and depressurization, rather than simply pressurizing, ensuring repeatable and reliable bottomhole switching action of the toothed, interlaced structure. It completes the connection and sealing of the entire wellbore. The combined action of the sand-blocking pipe and the sand-sinking pipe prevents the accumulation of solid impurities at moving parts, enhancing the reliability of the switching action. By incorporating an emergency structure and a retrievable, triggerable degradable structure, it achieves 100% wellbore opening and, if necessary, ensures 100% full-bore wellbore coverage during subsequent operations, thus guaranteeing the smooth progress of well completion operations. Attached Figure Description

[0029] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the structure of a toothed interlaced switch type oil well completion plug in the wellbore setting state according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the sand-blocking pipe in one embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of an emergency valve in one embodiment of the present invention;

[0033] Figure 4 This is a top view of an emergency valve in one embodiment of the present invention;

[0034] Figure 5 for Figure 4 Sectional view of AA;

[0035] Figure 6 for Figure 4 Sectional view of BB;

[0036] Figure 7 This is a schematic diagram of the toothed interlaced valve in one embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the outer cylinder structure in one embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the upstream toothed valve in one embodiment of the present invention;

[0039] Figure 10This is a cross-sectional view of the upstream toothed valve in one embodiment of the present invention;

[0040] Figure 11 This is a schematic diagram of the downstream toothed valve in one embodiment of the present invention;

[0041] Figure 12 This is a cross-sectional view of the downstream toothed valve in one embodiment of the present invention;

[0042] Figure 13 This is a cross-sectional view of a directional valve in one embodiment of the present invention;

[0043] Figure 14 This is a schematic diagram of the open state of the toothed interlaced valve in one embodiment of the present invention;

[0044] Figure 15 This is a schematic diagram of an embodiment of the present invention, showing the state in which the tip of the downstream toothed valve pushes the downstream toothed valve downward until it collides with the tip of the fixed tooth on the outer cylinder.

[0045] Figure 16 This is a schematic diagram of the downstream tooth valve sliding down along the tooth end face of the upstream tooth valve to the bottom of the tooth in one embodiment of the present invention.

[0046] Figure 17 This is a schematic diagram of the downstream tooth valve tooth tip entering the bottom of the toothed portion of the fixed tooth in one embodiment of the present invention.

[0047] Figure 18 This is a schematic diagram illustrating the state of the emergency valve spraying corrosive liquid in one embodiment of the present invention;

[0048] Figure 19 This is a schematic diagram illustrating the working principle of the sand settling valve in one embodiment of the present invention;

[0049] List of reference numerals in the attached diagram:

[0050] 1. Sand baffle pipe; 1-1. Oil wellhead; 2. Anchor plug; 2-1. Rubber ring; 2-2. Slip; 3. Emergency valve; 3-1. Valve body; 3-1-1. One-way orifice; 3-1-2. X-valve orifice; 3-1-3. Acid orifice; 3-2. Inner plug; 3-3. One-way ball; 3-4. X-valve; 3-4-1. X-shaped spring plate; 3-4-2. Steel ball; 3-5. Acid chamber; 3-6. Acid bladder; 3-7. Rupture disc; 3-8. Nozzle; 3-9. Pin; 4. Toothed staggered valve; 4-1. Outer cylinder; 4-1-1. Fixed tooth; 4-1-1-1. Toothed part; 4-1-1-2. Toothed groove part 4-1-2, Blind plug; 4-1-3, Oil inlet; 4-2, Upstream toothed valve; 4-2-1, Outer cylinder; 4-2-2, Central cylinder; 4-2-3, Upstream tooth; 4-2-4, Fixed wedge; 4-3, Downstream toothed valve; 4-3-1, Downstream tooth; 4-4, Central pipe; 4-4-1, Oil drain hole; 4-5, Directional valve; 4-5-1, Body; 4-5-2, Valve block; 4-5-3, Tension spring; 4-5-4, Fluid passage; 4-6, Spring; 4-7, Sealing structure; 5, Sand settling pipe; 5-1, Pipe body; 5-2, Flow channel hole; 5-3, Conical baffle; 6, Wellbore. Detailed Implementation

[0051] To make the embodiments, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0052] This invention discloses a toothed interlocking switch type well completion plug, which includes a sand-blocking pipe, an anchoring plug, an emergency valve, a toothed interlocking valve, and a sand-sinking pipe connected in sequence. Fluid can enter through the sand-sinking pipe and be transported to the sand-blocking pipe through the fluid channels of the toothed interlocking valve, the emergency valve, and the anchoring plug in sequence, and then exit from the oil production port on the side wall of the sand-blocking pipe. The fluid channel is formed by the connection of a first pre-drilled hole, a second pre-drilled hole, and a third pre-drilled hole respectively provided in the anchoring plug, the emergency valve, and the toothed interlocking valve.

[0053] The sand-blocking pipe is used to prevent solid impurities from settling into the well completion plug;

[0054] The anchoring plug includes slips for fitting against the inner wall of the well to suspend the completion plug;

[0055] The emergency valve contains a corrosive liquid that can be sprayed out under external force to corrode the slip and release the anchor plug.

[0056] The toothed interlaced valve is used to open or close the fluid passage;

[0057] The settling pipe is used for fluid entry and settling of solid impurities.

[0058] The toothed interlaced switch-type well completion plug of the present invention achieves repeatable and reliable bottom hole switching action through the toothed interlaced structure, completing the connection and sealing of the entire wellbore. The reliability of component movement is enhanced by the combined action of the sand-blocking pipe and the sand-sinking pipe. The full-bore of the wellbore is guaranteed in subsequent operations through the retrieveable and triggerable degradable structure. The smooth progress of well completion operations is guaranteed by the setting of emergency structure.

[0059] To more clearly illustrate the toothed interlaced switch type well completion plug of the present invention, a preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0060] As a preferred embodiment of the present invention, the toothed interlaced switching type oil well completion plug of the present invention, such as... Figure 1 As shown, the system includes a sand-blocking pipe 1, an anchoring plug 2, an emergency valve 3, a toothed cross valve 4, and a sand-sinking pipe 5 connected sequentially from top to bottom. Fluid can enter through the sand-sinking pipe 5 and be transported to the sand-blocking pipe 1 through the fluid channels of the toothed cross valve 4, the emergency valve 3, and the anchoring plug 2 in sequence, and then be output from the oil production hole on the side wall of the sand-blocking pipe 1. The fluid channel is formed by the connection of the first pre-drilled hole, the second pre-drilled hole, and the third pre-drilled hole respectively provided by the anchoring plug 2, the emergency valve 3, and the toothed cross valve 4.

[0061] See Figure 2 The sand-blocking pipe 1 is used to prevent solid impurities from settling into the completion plug. Specifically, the sand-blocking pipe 1 is a hollow circular tube, with one end being a blind plug and the other end connected to the anchor plug 2 via a male thread. The outer diameter of the sand-blocking pipe 1 is smaller than the outer diameter of the anchor plug 2, and it has four rows of six oil production holes evenly distributed on its side. The opening direction of the oil production holes 1-1 is inclined upward, and the size of the equivalent hydraulic diameter is larger than the maximum through-hole diameter of the entire completion plug.

[0062] The anchoring plug 2 includes slips 2-2, which are used to fit against the inner wall of the well to suspend the completion plug. Specifically, the anchoring plug 2 also includes a rubber ring 2-1 and an anchoring plug tubular structure. Both the rubber ring 2-1 and the slips 2-2 are fitted onto the outside of the anchoring plug tubular structure. The internal through-hole of the anchoring plug tubular structure is the aforementioned first pre-fabricated hole, which serves as part of the fluid channel. The anchoring plug 2 can be pressure-set and released via tubing or coiled tubing, and can also be retrieved via tubing or coiled tubing. The outer surfaces of the metal parts and the rubber ring parts of the anchoring plug 2 are made of non-degradable coatings, while the interior is made of degradable materials. Corrosive liquids can destroy the outer non-degradable coating, while the interior degradable material dissolves rapidly upon contact with corrosive liquids. The anchoring plug 2 is set above the depth of the producing layer and below the depth of the production pump. The slips 2-2 can support the entire completion plug against the well wall, and the rubber ring 2-1 divides the entire wellbore into upper and lower parts after setting.

[0063] The emergency valve 3 contains a corrosive liquid that can be ejected under external force to corrode the slip 2-2 and unseal the anchor plug 2. Furthermore, the emergency valve 3 can also serve as a temporary oil recovery route in case of a failure of the toothed interlocking valve 4. Preferably, the corrosive liquid in this application is acid.

[0064] Specifically, see Figures 3-6The emergency valve 3 includes a valve body 3-1, an inner plug 3-2, a single-flow ball 3-3, an X-valve 3-4, an acid chamber 3-5, an acid bladder 3-6, a rupture disc 3-7, a nozzle 3-8, and a pin 3-9. The valve body 3-1 is cylindrical with a hollow, stepped through-hole; the upper hole diameter is larger than the lower hole diameter. Four single-flow holes 3-1-1 are evenly distributed circumferentially on the upper part of the valve body, each containing a single-flow ball 3-3. In the same orientation as the single-flow holes 3-1-1, four X-valve holes 3-1-2 are evenly distributed circumferentially on the lower end face of the valve body. Between every two single-flow holes 3-1-1, four vertical acid holes 3-1-3 are evenly distributed circumferentially within the valve body. The acid outlet 3-1-3 is angled upwards on the valve body, pointing towards the connection of the anchor plug 2's slip 2-1. The middle section is divided into two non-connected parts by a rupture disc 3-7. Within the valve body 3-1, the thick-walled section corresponding to the small-diameter orifice is the acid chamber 3-5, which connects to the X valve orifice 3-1-2 at its lower part. An acid bladder 3-6 is placed inside the acid chamber 3-5. The acid bladder 3-6 is an acid-resistant rubber bladder filled with acid, and its outlet connects to the acid outlet 3-1-3. A nozzle 3-8 is installed at the outlet of the acid outlet 3-1-3. The inner flow channel of the nozzle 3-8 is conical and made of an acid-resistant material. The inner plug 3-2 is an outer stepped cylinder with a through-hole inside. The inner plug 3-2 includes a first structural part and a second structural part arranged vertically. The diameter of the first structural part of the inner plug 3-2 is larger than the diameter of the second structural part. The first structural part mates with the upper part of the inner hole of the valve body 3-1, and a seal is achieved at the single-flow orifice 3-1-1 by two O-rings. The height of the first structural part is less than the distance from the lower edge of the single-flow orifice 3-1-1 to the stepped surface of the inner hole of the valve body 3-1. The second structural part of the inner plug 3-2 mates with the lower part of the inner hole of the valve body 3-1, and a seal is achieved by one O-ring. The height of the second structural part is less than the distance from the stepped surface of the inner hole of the valve body 3-1 to the lower end face. The inner plug 3-2 is fixed in the inner hole of the valve body 3-1 by a pin 3-9. In the initial state, the inner plug 3-2 seals the single-flow orifice 3-1-1. The X valve 3-4 includes an X-shaped spring plate 3-4-1 and a steel ball 3-4-2, which are installed in the X valve hole 3-1-2. Both X valve 3-4 and inner plug 3-2 are opened by pressurizing the wellhead. The opening pressure of X valve 3-4 is greater than that of inner plug 3-2. The bursting pressure of rupture disc 3-7 is between the opening pressures of X valve 3-4 and inner plug 3-2.

[0065] Further, see Figure 7The toothed interlaced valve 4 is used to open or close the fluid passage. In a preferred embodiment of this application, the toothed interlaced valve 4 includes an outer cylinder 4-1, an upstream toothed valve 4-2, a downstream toothed valve 4-3, a central tube 4-4, a directional valve 4-5, and an elastic element. Preferably, the elastic element in this application is a spring 4-6. The outer cylinder 4-1 is the main body of the toothed interlaced valve and is a hollow, stepped cylinder. The outer cylinder includes a first tubular structure and a second tubular structure arranged vertically. The wall thickness of the first tubular structure is greater than that of the second tubular structure. Eight circumferentially distributed fixed teeth 4-1-1 are cut internally in the upper part of the first tubular structure. (See also...) Figure 8 The fixed tooth 4-1-1 is divided into a toothed portion 4-1-1-1 and a grooved portion 4-1-1-2. The thickness of the tooth is equal to the width at the stepped surface. The grooved portion 4-1-1-2 is a rectangular groove, formed by cutting off half of the toothed portion 4-1-1-1 and extending towards the top surface of the outer cylinder 4-1, with an extension distance greater than the maximum upward movement distance of the upstream toothed valve 4-2. The inclination angle of the toothed portion 4-1-1-1 is 60°, and its height is greater than the height of the teeth of the upstream toothed valve 4-2 and the downstream toothed valve 4-3. The bottom end face of the outer cylinder 4-1 is a blind plug 4-1-2, with eight oil inlet holes 4-1-3 distributed circumferentially on it, and a central tube 4-4 at the center. The blind plug 4-1-2 and the central tube 4-4 are fixed to the outer cylinder 4-1 by welding. The central tube 4-4 is a through-hole cylinder, with a sealing groove near the upper end. Six drain holes 4-4-1 are evenly distributed circumferentially in the middle section. Below the annulus between the outer cylinder 4-1 and the central tube 4-4, above the blind plug 4-1-2, a pressure spring 4-6 is fitted onto the central tube 4-4. The equivalent hydraulic diameter of the inlet hole 4-1-3 and the drain holes 4-4-1 is larger than the maximum through-hole diameter of the entire completion plug.

[0066] like Figure 9 and Figure 10As shown, the upstream toothed valve 4-2 is a cylindrical shape with the upper and lower parts of the central hole having the same diameter, connected in the middle by a necking. The upper part of the outer surface has a sealing groove with a diameter matching the inner diameter of the first tubular structure of the outer cylinder 4-1, achieving sealing through an O-ring. Specifically, the upstream toothed valve 4-2 includes an outer cylinder and a central cylinder. The outer cylinder is fitted over the central cylinder, and the outer cylinder's inner surface contracts radially to form an annular protrusion. The top of the central cylinder is connected to the outer cylinder through this annular protrusion. The central and outer cylinders are coaxially arranged, and the inner diameter of the annular protrusion is smaller than the inner diameter of the central cylinder. A sandwich is formed between the outer cylinder 4-2-1 and the central cylinder 4-2-2 of the upstream toothed valve 4-2. The lower end face of the outer cylinder 4-2-1 is line-cut with upstream teeth 4-2-3, evenly distributed circumferentially, totaling eight teeth. The inclination angle and thickness of the teeth are consistent with the inclination angle and thickness of the toothed portion 4-1-1-1. A fixed wedge 4-2-4, rectangular in shape, is positioned vertically at the tooth tip of the upstream tooth. Its width is slightly smaller than the width of the tooth groove portion 4-1-1-2, its thickness is the same as the thickness of the toothed portion 4-1-1-1, and its length is one-third of the extension distance of the tooth groove portion 4-1-1-2. The inner diameter of the central cylinder 4-2-2 matches the outer diameter of the central tube 4-4, forming a seal with an O-ring. Its outer diameter matches the inner diameter of the downstream toothed valve 4-3. A directional valve 4-5 is installed in the upper central hole of the upstream toothed valve 4-2. It is understood that the number of teeth in this application is only a preferred embodiment, and those skilled in the art can flexibly change the number of teeth, for example, 6, 10, 12, etc. It is understood that when the number of upstream teeth changes, the number of downstream teeth changes accordingly.

[0067] See Figure 13 The bottom of the directional valve 4-5 is an openable frustoconical valve block 4-5-2, which is fixed to the body 4-5-1 by a tension spring 4-5-3. The diameter of the lower surface of the valve block 4-5-2 is larger than the diameter of the constriction at the center hole of the upstream toothed valve 4-2, which can seal the constriction. Four fluid passage holes 4-5-4 are evenly distributed around the circumference of the body 4-5-1, which can change the flow direction of the fluid.

[0068] like Figure 11 and Figure 12As shown, the downstream gear valve 4-3 is a hollow cylinder with four circumferentially distributed downstream teeth 4-3-1 cut at its upper end. The inclination angle of these teeth is the same as that of the teeth in the upstream gear valve 4-2, and the thickness of the teeth is slightly less than twice the thickness of the teeth in the upstream gear valve 4-2, thus ensuring engagement with both the upstream gear valve 4-2 and the fixed teeth 4-1-1. The outer diameter of the lower end matches the inner diameter of the lower part of the outer cylinder 4-1, and an O-ring is used to achieve a seal. The inner diameter of the lower end matches the outer diameter of the central tube 4-4, and an O-ring is used to achieve a seal. A sealing structure 4-7 is formed in the annular space between the central tube 4-4 and the outer cylinder 4-1. Within the vertical range of motion of this sealing structure 4-7, the oil drain hole 4-4-1 on the central tube 4-4 can be opened and closed.

[0069] When installing the toothed interlaced valve 4, first insert the upstream toothed valve 4-2 and the downstream toothed valve 4-3 into the lower end face of the outer cylinder 4-1. During insertion, the teeth of the upstream toothed valve 4-2 should face downwards, while the teeth of the downstream toothed valve 4-3 should face upwards. The fixing wedge 4-2-4 of the upstream toothed valve 4-2 should be aligned with the tooth groove portion 4-1-1-2 of the fixing tooth 4-1-1. To ensure that the toothed interlaced valve 4 is in the open state during installation, align the tip of the teeth of the downstream toothed valve 4-3 with the tooth groove portion 4-1-1-2 before insertion. Then, mount the spring 4-6 onto the central tube 4-4, fix it to the blind plug 4-1-2, and insert it into the central cylinder 4-2-2 of the upstream toothed valve 4-2, fixing it to the bottom of the outer cylinder 4-1. Finally, install the directional valve 4-5 into the upper part of the central hole of the upstream toothed valve 4-2. The through hole of the central tube 4-4, the through hole of the downstream toothed valve 4-3, the through hole of the upstream toothed valve 4-2, and the liquid passage hole of the directional valve 4-5 together constitute the third prefabricated hole.

[0070] The settling pipe 5 is used for fluid entry and settling of solid impurities. See details. Figure 19 The bottom of the outer cylinder 5-1 of the sand-sinking pipe 5 is a spherical head, which facilitates the lowering of the entire completion plug into the well. Near the upper part of the side wall, there are 8 flow channel holes 5-2 evenly distributed around the circumference. The equivalent hydraulic diameter is larger than the maximum through-hole diameter of the entire completion plug. Inside the sand-sinking pipe 5 is a conical baffle 5-3. The upper surface of the baffle is located above the flow channel holes, and the lower end face is a circular hole.

[0071] The working principle of the toothed interlocking switch type oil well completion plug of this application is as follows:

[0072] See Figures 14-17With the toothed interleaved valve 4 closed, the entire completion plug is set within the wellbore 6, dividing the wellbore 6 into two disconnected sections. The wellhead pressure required for the valve to open and close is determined by the springs 4-6 within the toothed interleaved valve 4. This pressure can be adjusted by replacing springs 4-6, thereby matching the pressure of the producing formation. Pressurizing the wellhead with a pump truck allows the toothed interleaved valve 4 to open and close, thus altering the overall connectivity of the wellbore.

[0073] During oil production, the sand-blocking valve 1 prevents solid impurities in the wellbore 6 from settling into the anchor plug 2 and the toothed cross valve 4, causing them to get stuck in the moving parts and affecting their normal operation. At the bottom of the completion plug, when the formation fluid carrying solid impurities enters the sand-sinking pipe 5 through the flow channel hole 5-2, the fluid flows downward, and the flow space gradually increases, resulting in a gradual decrease in flow velocity. At low flow velocity, the solid impurities it carries gradually detach from the fluid under gravity and settle to the bottom of the sand-sinking pipe 5, while the fluid enters the conical body through the circular opening of the conical baffle 5-3. Similarly, the flow velocity decreases, again creating a settling effect on the solid impurities. Afterward, the fluid enters the oil inlet hole 4-1-3 of the toothed cross valve 4, ensuring that it carries as few solid impurities as possible and avoiding affecting the moving parts of the toothed cross valve 4.

[0074] During oil production, for the toothed interlocking valve 4, the resulting sealing structure 4-7 is located above the drain hole 4-4-1. After impurities are settled through the sand settling pipe 5, the oil flows into the cavity of the sealing structure 4-7 through the inlet hole 4-1-3, and then into the central pipe 4-4 through the drain hole 4-4-1, thus flowing upward to the directional valve 4-5. At this time, the valve block 4-5-2 of the directional valve 4-5 is pulled by the tension spring 4-5-3 and cooperates with the body 4-5-1. The oil flows through the neck and continues to flow upward through the fluid passage 4-5-4 on the side wall of the directional valve 4-5. After flowing through the anchor plug 2 and the sand baffle pipe 1, it is discharged into the space above the wellbore 6 and then discharged to the surface by the oil production pump. When the toothed interlocking valve 4 closes, pressure is applied through the wellhead, and this pressure acts on the valve block 4-5-2 of the directional valve 4-5, causing the valve block 4-5-2 to move downwards and block the oil flow passage at the neck of the central orifice. Simultaneously, under this pressure, the upstream toothed valve 4-2 moves downwards, its teeth meshing with the teeth of the downstream toothed valve 4-3, pushing the downstream toothed valve 4-3 downwards together until the tip of the downstream toothed valve 4-3 collides with the tip of the toothed portion 4-1-1-1 of the fixed tooth 4-1-1 on the outer cylinder 4-1. During this process, constrained by the groove portion 4-1-1-2 of the fixed tooth 4-1-1, neither the upstream toothed valve 4-2 nor the downstream toothed valve 4-3 rotates. At this time, the spring 4-6 is in a compressed state, and the sealing structure 4-7 has moved downwards and blocked the drain hole 4-4-1 on the central tube 4-4. The wellhead remains unpressurized. Upstream toothed valve 4-2 and downstream toothed valve 4-3 continue to move downwards. Without the obstruction of the tooth tip of toothed portion 4-1-1-1, downstream tooth 4-3-1 slides down the end face of upstream tooth 4-2-3 to the bottom of upstream tooth 4-2-3, undergoing a small-angle rotation. This causes them to spatially intersect within the corresponding range of the toothed portion 4-1-1-1 of fixed tooth 4-1-1. At this point, the wellhead is depressurized, and the elastic force of spring 4-6 acts on the sealing structure 4-7. Downstream toothed valve 4-3 pushes upstream toothed valve 4-2 upwards. The top of downstream tooth 4-3-1 enters the tooth end face of the toothed portion 4-1-1-1 of fixed tooth 4-1-1 and gradually slides to the bottom of the toothed portion 4-1-1-1. Although piston structure 4-7 moves upwards, it still blocks the drain hole 4-4-1, thus closing the oil flow channel. If the toothed interlocking valve 4 is opened from closed, the wellhead is pressurized, pushing the upstream toothed valve 4-2 and the downstream toothed valve 4-3 to move up and down. This causes the teeth of the downstream toothed valve 4-3 to engage with the groove portion 4-1-1-2 of the fixed tooth 4-1-1, causing the piston structure 4-7 to move upward, opening the drain hole 4-4-1, and resuming oil production. During the entire up-and-down movement, the upstream toothed valve 4-2 will not rotate due to the constraint of the fixed wedge 4-2-4, thus ensuring the stability of the engagement. By repeating this process, the toothed interlocking valve 4 can be repeatedly opened and closed, enabling pump running, pump inspection, or other operations without well pressure.It is understood that the positions of spring 4-6 and oil drain hole 4-4-1 are not explicitly defined. Preferably, the top of spring 4-6 is located below oil drain hole 4-4-1. In actual operation, since the spring is a spiral structure, even if oil drain hole 4-4-1 is located below the top of spring 4-6, it will not affect the flow of oil drain hole 4-4-1. Therefore, those skilled in the art can flexibly set the positional relationship between the two according to the actual situation.

[0075] When the toothed interleaved valve 4 fails to open due to unforeseen circumstances, pressure is applied through the wellhead to a level higher than the pressure required to open and close the toothed interleaved valve 4. Due to the area difference between the upper and lower surfaces of the inner plug 3-2 of the emergency valve 3, this pressure creates a pressure differential between the upper and lower surfaces of the inner plug 3-2. Under the action of this pressure differential, the inner plug 3-2 is forced to move downwards by shearing pin 3-9 until it reaches the diameter change point of the valve body 3-1, thereby opening the single-flow orifice 3-1-1. Oil flows through the single-flow orifice 3-1-1, pushing aside the single-flow ball 3-3 to form an oil flow channel, entering the valve body 3-1, and then upwards into the upper part of the wellbore 6 for oil production operations.

[0076] When subsequent operations require a complete full-bore wellbore, meaning there are no obstructions within the wellbore, the completion plug can be retrieved using coiled tubing or tubing. However, if unsealing and retrieval are not possible or unnecessary after prolonged operation, acid injection can be used. (See [reference needed]). Figure 18 This releases the anchor plug 2, causing the entire completion plug to slide to the bottom of the well. The working process involves pressurizing the wellhead to a pressure higher than the pressure required to open the inner plug 3-2 of the emergency plug 3. At this time, the upstream toothed valve 4-2 moves downwards, and the high-pressure fluid acts on the X valve 3-4 at the bottom of the emergency valve 3. The pressure pushes the steel ball 3-4-2 inwards, allowing the high-pressure fluid to enter the acid chamber 3-5. After depressurization at the wellhead, the X-shaped spring plate 3-4-1 bounces the steel ball 3-4-2 back to seal the channel, making the acid chamber 3-5 a high-pressure fluid chamber. The high-pressure fluid compresses the acid bladder 3-6, and the compressed acid rises to the point where the rupture disc 3-7 fractures, causing the rupture disc 3-7 to rupture and creating a connecting channel in the acid orifice 3-1-3. The acid in the acid sac 3-6 is ejected from the nozzle 3-8 through the acid hole 3-1-3, impacting the slips 2-2 and rubber ring 2-1 of the anchor plug 2, causing damage to the slips 2-2 and rubber ring 2-1. The slips 2-2 loosens rapidly. At the same time, the acid damages the coating of the slips 2-2 and rubber ring 2-1, causing the anchor plug 2 to undergo a trigger-induced degradation effect, thereby triggering the dissolution of the internal material. The anchor plug 2 is in an acid environment, accelerating its desealing failure, so that the entire completion plug falls into the bottom pocket of the well, forming the full bore of the wellbore 6.

[0077] The technical solutions described in the above embodiments of this application have at least the following technical effects and advantages:

[0078] The toothed, interlaced, switchable well completion plug of this invention enables wellbore operation without pressure, including operation with various downhole tools such as production pumps and maintenance pumps. It is not limited by the tools themselves or the production formation. The wellhead pressure can be determined by adjusting the spring force according to the pressure of the production formation, thus matching the pressure to the formation pressure. This tool completes the action by pressurizing and depressurizing, rather than simply pressurizing, ensuring repeatable and reliable bottomhole switching action of the toothed, interlaced structure. It completes the connection and sealing of the entire wellbore. The combined action of the sand-blocking pipe and the sand-sinking pipe prevents the accumulation of solid impurities at moving parts, enhancing the reliability of the switching action. By incorporating an emergency structure and a retrievable, triggerable degradable structure, it achieves 100% wellbore opening and, if necessary, ensures 100% full-bore wellbore coverage during subsequent operations, thus guaranteeing smooth well completion.

[0079] It should be noted that in the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0080] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0081] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0082] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A toothed, interlocking switch type oil well completion plug, characterized in that, The well completion plug includes a sand-blocking pipe, an anchoring plug, an emergency valve, a toothed cross valve, and a sand-sinking pipe connected in sequence. Fluid can enter through the sand-sinking pipe and be transported to the sand-blocking pipe through the fluid channels of the toothed cross valve, the emergency valve, and the anchoring plug in sequence, and then exit from the oil production port on the side wall of the sand-blocking pipe. The fluid channel is formed by the connection of a first pre-drilled hole, a second pre-drilled hole, and a third pre-drilled hole respectively provided in the anchoring plug, the emergency valve, and the toothed cross valve. The sand-blocking pipe is used to prevent solid impurities from settling into the well completion plug; The anchoring plug includes slips for fitting against the inner wall of the well to suspend the completion plug; The emergency valve contains a corrosive liquid that can be sprayed out under external force to corrode the slip and release the anchor plug. The toothed interlaced valve is used to open or close the fluid passage; The settling pipe is used for fluid entry and settling of solid impurities; The toothed interlaced valve includes an outer cylinder, an upstream toothed valve, a downstream toothed valve, a central tube, and an elastic element; the upstream toothed valve, the downstream toothed valve, the central tube, and the elastic element are all installed inside the outer cylinder; The outer cylinder is a stepped tubular structure, which includes a first tubular structure and a second tubular structure arranged vertically. The wall thickness of the first tubular structure is greater than that of the second tubular structure. An even number of fixed teeth are arranged circumferentially on the inner wall of the first tubular structure. The fixed teeth include tooth-shaped parts and tooth groove parts. The tooth-shaped parts are used to limit the movement range of the downstream tooth valve, and the tooth groove parts are used to limit the movement range of the upstream tooth valve. The bottom of the central tube is sealed and detachably installed at the bottom of the outer cylinder. The central tube has an oil inlet hole along the circumference and a number of oil outlet holes are evenly distributed along the circumference on the middle sidewall of the central tube. The upstream toothed valve includes an outer cylinder and a central cylinder. The outer cylinder is sleeved outside the central cylinder and connected by a necking. The outer diameter of the outer cylinder matches the inner diameter of the first tubular structure. The outer diameter of the central cylinder matches the inner diameter of the downstream toothed valve. The inner diameter of the central cylinder matches the outer diameter of the central tube. The lower end face of the outer cylinder is cut with upstream teeth. The number of upstream teeth is the same as the number of fixed teeth. The inclination angle and width of the upstream teeth are the same as the inclination angle and width of the fixed teeth. A fixed wedge is fixed in the vertical direction of the tooth tip of the upstream teeth. The width of the fixed wedge matches the tooth groove. The downstream toothed valve has downstream teeth cut at its upper end. The number of downstream teeth is half the number of upstream teeth. The inclination angle of the downstream teeth is the same as that of the upstream teeth. The downstream teeth can mesh with the fixed teeth and the upstream teeth. The bottom outer edge of the downstream toothed valve matches the inner diameter of the second tubular structure. The downstream toothed valve is used to convert linear motion into rotational motion. The elastic element is sleeved outside the central tube, and the bottom of the elastic element abuts against the bottom of the outer cylinder. The elastic element is used to provide support for the downstream toothed valve. The annular space between the downstream toothed valve and the central tube forms a piston structure, and the up-and-down movement of the piston structure can open or close the oil drain hole on the central tube.

2. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The outer diameter of the sand-blocking pipe is smaller than the outer diameter of the anchor plug. The end of the sand-blocking pipe away from the anchor plug is sealed. Several oil-producing holes are evenly distributed along the circumference of the side wall of the sand-blocking pipe. The opening direction of the oil-producing holes is inclined upward.

3. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The anchoring plug also includes a rubber ring, which is fitted over the slip. The outer surface of the slip is coated with a non-degradable coating, while the interior of the slip is made of a degradable material. The non-degradable coating can be corroded by the corrosive liquid.

4. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The emergency valve includes a valve body, an inner plug, and an X valve. The valve body is a cylindrical structure with stepped through holes inside. The diameter of the holes at the top of the valve body is larger than the diameter of the holes at the bottom of the valve body. A number of even-numbered single-flow holes are evenly distributed around the top of the valve body, and a single-flow ball is installed in each single-flow hole. The inner plug includes a first structural part and a second structural part arranged vertically. The first structural part matches the upper aperture of the valve body, and the second structural part matches the lower aperture of the valve body. The inner plug has a second pre-made hole in the middle. The inner plug is fixed in the upper aperture of the valve body by a pin. The height of the first structural part is less than the distance from the lower edge of the single flow orifice to the step surface of the stepped through hole of the valve body, and the height of the second structural part is less than the distance from the step surface of the stepped through hole of the valve body to the lower end face. In the initial state, the inner plug blocks the single flow orifice.

5. The toothed interlaced switch type oil well completion plug according to claim 4, characterized in that, An acid chamber is provided at the bottom of the valve body, and an acid bladder is provided inside the acid chamber. An acid hole is provided between any two adjacent single flow holes. Several acid holes are evenly distributed around the circumference of the valve body and are inclined upward at the outlet of the acid hole. The acid hole is vertically arranged and a rupture disc is horizontally installed in the middle. The bottom of the acid hole is connected to the top of the acid chamber. The valve body is also provided with X-valve holes, and a number of even-numbered X-valve holes are in the same position as the single flow orifice and are evenly distributed circumferentially along the lower end face of the valve body; the bottom of the acid chamber is connected to the X-valve holes, and an X-shaped spring plate and a steel ball are provided inside the X-valve holes. Both the X-valve and the inner plug are opened by wellhead pressure. The opening pressure of the X-valve is greater than the opening pressure of the inner plug, and the bursting pressure of the rupture disc is between the opening pressure of the X-valve and the inner plug.

6. The toothed interlaced switch type oil well completion plug according to claim 5, characterized in that, A nozzle is installed at the outlet of the acid orifice; the inner flow channel of the nozzle is conical, and the nozzle is made of a material resistant to acid corrosion.

7. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The toothed interlaced valve also includes a directional valve, which is installed on the top of the upstream toothed valve. The directional valve includes a valve block and a directional valve body. The side wall of the directional valve body has a fluid passage hole. The valve block is truncated cone-shaped and is operably installed at the bottom of the directional valve body. The upper surface of the valve block is fixed by tension spring. The lower surface of the valve block matches the bottom of the directional valve body. The diameter of the lower surface of the valve block is larger than the diameter of the constriction at the center hole of the upstream toothed valve. The valve block can block the constriction.

8. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The height of the toothed portion is greater than the height of the upstream tooth and the downstream tooth.

9. The toothed interlaced switch type oil well completion plug according to claim 1, characterized in that, The bottom of the sedimentation pipe is a spherical head, and several flow channel holes are evenly distributed circumferentially on the upper part of the side wall of the sedimentation pipe. A conical baffle is provided inside the upper end of the sedimentation pipe, and the upper surface of the conical baffle is located above the flow channel holes, while the lower end face is a circular hole.

Images