Water injection well head and valve freeze protector

Abstract

The present application belongs to the technical field of oilfield production equipment, and particularly relates to a water injection well wellhead and valve anti-freezer, which comprises a lower joint, a main body center pipe, a rubber sleeve, a sliding sleeve, a one-way leather cup, a tray, and an upper joint. An annular groove is formed in the end of the tray, and a sealing ring is arranged in the annular groove. A plurality of liquid passing holes are formed in the lower end of the sliding sleeve. Four supporting centralizing columns are arranged on the upper part of the main body center pipe. The upper joint is threadedly connected to one end of the main body center pipe, and the lower joint is threadedly connected to the other end of the main body center pipe. The sliding sleeve is sleeved on the main body center pipe and is supported by the supporting centralizing columns. The tray is threadedly installed on the sliding sleeve near the end of the upper joint. The one-way leather cup is seated on the tray. The rubber sleeve is sleeved on the sliding sleeve with the liquid passing holes. The water injection and polymer injection well can avoid the freezing of the valve and wellhead in winter. The well cannot be backwashed due to the freezing of the liquid in the casing in winter. The wellhead is convenient for well repair operation, energy saving, and environmental protection. The structure is simple, the cost is low, and the wellhead is economical and applicable.

Description

Technical Field

[0001] This invention belongs to the technical field of oilfield production equipment, specifically relating to an antifreeze device for water injection wellheads and valves. Background Technology

[0002] During winter in northern oilfields, both water injection wells and polymer injection wells experience casing valve damage from freezing. The valves are often frozen solid up to 1.5 meters below the wellhead, preventing backwashing. While steam-powered equipment can solve the problem, it takes half a day and causes environmental pollution around the well site. Furthermore, during pressurized environmental protection construction in water and polymer injection wells, the pressure inside the casing makes the process of hanging the tubing extremely difficult. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a wellhead and valve antifreeze device for water injection wells. The antifreeze device is simply placed below the first tubing at the wellhead. Due to the use of a sliding, inverted one-way valve cup, it can both backwash the well and clear accumulated water from the casing near the wellhead.

[0004] The technical solution adopted in this invention is as follows: a water injection wellhead and valve antifreeze device, the antifreeze device includes a lower connector, a main central tube, a rubber sleeve, a sliding sleeve, a one-way cup, a tray, and an upper connector; the end of the tray has an annular groove, and a sealing ring is provided in the annular groove; the lower end of the sliding sleeve has several fluid passage holes; the upper part of the main central tube is provided with 4 support and straightening columns; the upper connector is threaded to one end of the main central tube, and the lower connector is threaded to the other end of the main central tube; the sliding sleeve is fitted on the main central tube and supported by the support and straightening columns; the tray is threadedly installed on the sliding sleeve near the upper connector; the one-way cup sits on the tray; and the rubber sleeve is fitted on the sliding sleeve at the end with the fluid passage holes.

[0005] Furthermore, the sliding sleeve is provided with a groove for a ferrule sleeve.

[0006] Furthermore, the number of liquid passage holes is four.

[0007] Furthermore, the four supporting and straightening columns are evenly distributed in the circumferential direction and staggered in the axial direction.

[0008] Furthermore, a liquid-passing ring cavity is left between the main central tube and the sliding sleeve.

[0009] Further, the process method for preventing freezing and backwashing well using the anti-freezing device is as follows: the anti-freezing device is lowered to below the first oil pipe of the wellhead, the one-way cup is sealed with the casing through interference fit; under the action of the liquid pressure in the well, the one-way cup goes up together with the slide and the tray, and the sealing ring at the upper end of the tray is attached to the lower end surface of the upper joint, the sealing ring realizes the sealing of the liquid passage cavity outside the slide, and the sealing ring and the one-way cup realize the sealing of the upper cavity and the lower cavity of the anti-freezing device; at this time, the cavity above the upper end of the anti-freezing device to the casing of the wellhead is empty of water, and the wellhead or the wellhead valve is prevented from freezing.

[0010] When backwashing well is needed, the backwashing liquid is injected into the well from the wellhead, under the action of the liquid pressure, the one-way cup goes down together with the slide and the tray, and after the tray goes down, the sealing ring is separated from the lower end surface of the upper joint; at this time, the liquid above the anti-freezing device enters the liquid passage cavity between the main body center pipe and the slide, under the action of the backwashing liquid pressure, the backwashing liquid pushes away the rubber sleeve tightly sleeved at the end of the liquid passage hole, the backwashing liquid enters the well through the liquid passage hole to start backwashing well; after the well is washed, the rubber sleeve tightly sleeved on the liquid passage hole automatically shrinks, the liquid in the well pushes the one-way cup to go up, and the sealing is realized again.

[0011] The anti-freezing device for the wellhead and valve of the injection well has the advantages that: the anti-freezing device is lowered to below the first oil pipe of the wellhead, the one-way cup is sealed with the casing through interference fit, under the action of the liquid pressure in the well, the one-way cup goes up together with the slide and the tray, and the sealing ring at the upper end of the tray is attached to the lower end surface of the upper joint, the sealing ring realizes the sealing of the liquid passage cavity outside the slide, and the sealing ring and the one-way cup realize the sealing of the upper cavity and the lower cavity of the anti-freezing device; at this time, the cavity above the upper end of the anti-freezing device to the casing of the wellhead is empty of water, and the wellhead or the wellhead valve is prevented from freezing. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a structural schematic diagram of the anti-freezing device in example one;

[0013] Figure 2 is a structural schematic diagram of the lower joint in example one;

[0014] Figure 3 is a structural schematic diagram of the main body center pipe in example one;

[0015] Figure 4 is a structural schematic diagram of the rubber sleeve in example one;

[0016] Figure 5 is a structural schematic diagram of the slide in example one;

[0017] Figure 6 is a structural schematic diagram of the one-way cup in example one;

[0018] Figure 7 is a structural schematic diagram of the tray in example one;

[0019] Figure 8 is a structural schematic diagram of the upper joint in Example 1. DETAILED DESCRIPTION Embodiment

[0020] Referring to the drawings, a water injection wellhead and valve anti-freezer comprises a lower joint 1, a main body central pipe 2, a rubber sleeve 3, a sliding sleeve 4, a one-way leather cup 5, a tray 6, and an upper joint 7; the end of the tray is provided with a ring groove 61, and a sealing ring is arranged in the ring groove; the lower end of the sliding sleeve is provided with a plurality of liquid passing holes 41; the upper part of the main body central pipe is provided with four supporting centralizers 21; the upper joint is threadedly connected with one end of the main body central pipe, and the lower joint is threadedly connected with the other end of the main body central pipe; the sliding sleeve is sleeved on the main body central pipe and is supported by the supporting centralizers, the tray is threadedly installed on the sliding sleeve close to one end of the upper joint, the one-way leather cup is seated on the tray, and the rubber sleeve is sleeved on the sliding sleeve with the liquid passing holes at one end; the sliding sleeve is provided with a clamping groove for clamping the rubber sleeve; the number of the liquid passing holes is four; the four supporting centralizers are distributed in a circular manner in the circumferential direction and are distributed in a staggered manner in the axial direction; and a liquid passing ring cavity is left between the main body central pipe and the sliding sleeve.

[0021] The working principle of the anti-freezer is as follows: under the action of the liquid pressure in the well, the one-way leather cup goes up together with the sliding sleeve and the tray, and the sealing of the upper and lower cavities of the anti-freezer is realized by the sealing ring abutting against the lower end face of the upper joint and the one-way leather cup in interference fit with the casing. When the well is backwashed, the backwashing liquid is injected from the wellhead into the well to push the one-way leather cup together with the sliding sleeve and the tray to go down, the sealing ring is separated from the lower end face of the upper joint, the liquid in the upper part of the anti-freezer enters the liquid passing ring cavity between the main body central pipe and the sliding sleeve, the backwashing liquid pushes away the rubber sleeve sleeved at the end of the liquid passing hole, and the backwashing liquid enters the well through the liquid passing hole to start the backwashing of the well.

[0022] The anti-freezer is lowered below the first oil pipe at the wellhead, and the one-way leather cup is sealed with the casing in interference fit. Under the action of the liquid pressure in the well, the one-way leather cup goes up together with the sliding sleeve and the tray, the sealing ring at the upper end of the tray abuts against the lower end face of the upper joint, the sealing of the liquid passing ring cavity outside the sliding sleeve is realized by the sealing ring, and the sealing of the upper and lower cavities of the anti-freezer is realized by the sealing ring and the one-way leather cup. At this time, the cavity from the upper end of the anti-freezer to the casing at the wellhead is empty and has no water, so that the wellhead or the wellhead valve will not be frozen and damaged.

[0023] When the well needs to be backwashed, the backwash liquid is injected into the well from the wellhead. Under the push of the liquid pressure, the one-way leather cup goes down together with the sliding sleeve and the tray. After the tray goes down, the sealing ring is separated from the lower end surface of the upper joint. At this time, the liquid above the freeze-proof device enters the liquid passing ring cavity between the main body central pipe and the sliding sleeve. Under the action of the backwash liquid pressure, the backwash liquid pushes away the rubber sleeve tightly sleeved at the end of the liquid passing hole, and the backwash liquid enters the well through the liquid passing hole to start backwashing the well. After the well is washed, the rubber sleeve tightly sleeved at the liquid passing hole automatically contracts, the liquid in the well pushes the one-way leather cup up, and sealing is realized again.

[0024] Before winter comes, open the casing valve and drain the accumulated water at the wellhead. The accumulated water about 1.5 meters from the wellhead can also be pumped out by a manual pump, and then the valve is closed. In addition, in the case of pressure environmental protection construction, after the installation of the freeze-proof device, the first oil pipe and the oil pipe hanger, the casing will not spray water, which is convenient to operate and energy-saving and environmentally friendly.

Claims

1. A freeze protector for the wellhead and valve of a water injection well, characterized in that: The antifreeze device includes a lower connector, a main central tube, a rubber sleeve, a sliding sleeve, a one-way cup, a tray, and an upper connector. The tray has an annular groove at its end, within which a sealing ring is installed. The lower end of the sliding sleeve has several liquid passage holes. The upper part of the main central tube has four supporting columns. The upper connector is threaded to one end of the main central tube, and the lower connector is threaded to the other end of the main central tube. The sliding sleeve is fitted onto the main central tube and supported by the supporting columns. The tray is threaded onto the sliding sleeve near the upper connector. The one-way cup rests on the tray, and the rubber sleeve is fitted onto the sliding sleeve at the end with the liquid passage holes. The sliding sleeve is provided with a groove for the ferrule sleeve; The number of liquid passage holes is 4; The antifreeze is lowered below the first tubing at the wellhead. The one-way cup and casing are sealed with an interference fit to achieve well fluid sealing. The upper and lower cavities of the antifreeze are sealed by the sealing ring and the one-way cup.

2. The antifreeze device for the wellhead and valve of the water injection well according to claim 1, characterized in that: The four supporting and straightening columns are evenly distributed in the circumferential direction and staggered in the axial direction.

3. The antifreeze device for the wellhead and valve of the water injection well according to claim 1, characterized in that: A liquid-passing ring cavity is left between the main central tube and the sliding sleeve.

4. The antifreeze device for the wellhead and valve of the water injection well according to any one of claims 1-3, characterized in that: The process of using the aforementioned antifreeze device for wellhead antifreeze and backwashing is as follows: Under the action of the liquid pressure inside the well, the one-way cup, along with the sliding sleeve and the tray, moves upward, causing the sealing ring at the upper end of the tray to abut against the lower end face of the upper connector. The sealing ring seals the external liquid-passing ring cavity of the sliding sleeve, and the sealing ring and the one-way cup seal the upper and lower pipe cavities. At this time, the casing from the upper end of the antifreeze device to the wellhead is a waterless cavity, thus preventing the wellhead or wellhead valve from freezing. When backwashing is required, backwashing fluid is injected into the well from the wellhead. Under the pressure of the fluid, the one-way cup, along with the sliding sleeve and the tray, moves downward. After the tray moves downward, the sealing ring separates from the lower end face of the upper connector. At this time, the fluid above the antifreeze enters the fluid passage chamber between the main body central tube and the sliding sleeve. Under the pressure of the backwashing fluid, the backwashing fluid pushes open the rubber sleeve tightly fitted at the end of the fluid passage hole, and the backwashing fluid enters the well through the fluid passage hole to start backwashing. After the well is flushed, the rubber sleeve tightly fitted on the fluid passage hole automatically retracts, and the liquid inside the well pushes the one-way cup upward, achieving a seal again.

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