Freezing box for oil and gas well mouth hidden danger treatment

Abstract

The utility model provides a freezing box for oil and gas well mouth hidden danger treatment. The freezing box comprises a freezing box body, a freezing process and a connecting unit. Wherein the freezing box body is provided with a hollow cavity and comprises a first body and a second body; the freezing process comprises a freezing pipe, an inlet and an outlet; wherein the freezing pipe is arranged on the first body and the second body; the inlet and the outlet are formed in the freezing pipe and are respectively used for freezing substances to enter and exit the freezing pipe; the connecting unit comprises a first connecting assembly and a second connecting assembly which can connect the two ends of the first body and the two ends of the second body respectively. According to the utility model, the installation time of the liquid nitrogen freezing process can be obviously reduced, the workload of field operators is reduced, the pre-freezing operation time is reduced, and the influence on the freezing effect caused by larger temperature difference between the upper part and the lower part of the freezing process in the freezing operation process is eliminated.

Description

Technical Field

[0001] The utility model relates to the technical field of treatment of hidden danger wells of oil and natural gas, and in particular to a freezing box used for treatment of hidden dangers at wellheads of oil and gas wells. Background Art

[0002] The freezing temporary plugging technology is: under the wellhead pressure state, the freezing temporary plugging device is used to inject temporary plugging agent into the annulus of each layer of casing and the oil pipe, and the temperature around the casing is kept at a low temperature by using a freezing medium outside the casing. After a certain period of freezing operation, the temporary plugging agent in the annulus of each layer of casing and the oil pipe is condensed into a bridge plug, temporarily isolating the pressure in the well, so as to achieve the purpose of safely replacing the leaking wellhead device.

[0003] At present, the technology for resolving hidden dangers of wellhead replacement under pressure has been improved from temporary freezing plugging technology using dry ice as the freezing medium to temporary freezing plugging technology using liquid nitrogen as the freezing medium.

[0004] The freezing temporary plugging technology using liquid nitrogen as a freezing medium is a new process and technology for well repair under pressure. Its principle is that liquid nitrogen circulates continuously in the bellows wrapped around the surface casing, and absorbs heat through rapid gasification of liquid nitrogen, thereby reducing the temperature around the surface casing. As a control system for liquid nitrogen temperature control, the intelligent temperature-controlled liquid nitrogen freezing system can keep the temperature near the surface casing constant at -55℃~50℃. Through the continuous supply of liquid nitrogen, the low temperature can gradually cool the casing layers at the wellhead from the outside to the inside until the temporary plugging agent forms a freezing bridge plug in the oil and casing, and finally isolates the pressure in the well.

[0005] A Chinese patent document with publication number CN106337670A and publication date January 18, 2017 discloses a freezing box device suitable for a wellhead freezing temporary plugging process of an oil well. The device comprises two semi-circular ring box bodies connected to each other, the two semi-circular ring box bodies are hinged at one radial side end by hinges, and the two semi-circular ring box bodies are connected at the other radial side end by a locking device. The semi-circular ring box body is divided into an outer box and an inner box, the inner box is arranged inside the outer box in a pull-out manner, and a box cover is arranged at the upper end of the inner box. The inner wall of the outer box is provided with a limit table for preventing the inner box from escaping upward. Observation windows are provided on both the outer box and the inner box. The freezing box device described in the above patent document is designed to be hinged and telescopic, so that the device saves space and is easy to transport. However, the installation of the liquid nitrogen freezing process is relatively difficult at present, and it takes 3 to 4 people about 1 hour to complete the installation. The pre-freezing operation time is relatively long. The use of an articulated and telescopic freezing box cannot solve the problem of a large temperature difference between the upper and lower freezing process during the freezing operation, which affects the freezing effect. Utility Model Content

[0006] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to significantly reduce the installation time of the liquid nitrogen freezing process, reduce the workload of on-site operators, reduce the pre-freezing operation time, and eliminate the impact of the large temperature difference between the upper and lower freezing processes on the freezing effect during the freezing operation.

[0007] In order to achieve the above-mentioned purpose, the utility model provides a freezing box for treating hidden dangers at wellheads of oil and gas wells.

[0008] The freezing box may include a freezing box body, a freezing process and a connecting unit; wherein the freezing box body has a hollow cavity and includes a first body and a second body; the freezing process includes a freezing pipe, an inlet and an outlet; wherein the freezing pipe is arranged on the first body and the second body; the inlet and the outlet are arranged on the freezing pipe, and are used for freezing materials to enter and exit the freezing pipe respectively; the connecting unit includes a first connecting component and a second connecting component, both of which can connect the two ends of the first body and the second body respectively.

[0009] Optionally, the cross-section of the cavity may be circular, elliptical or polygonal.

[0010] Optionally, the freezing tube may be embedded in the inward walls of the first body and the second body.

[0011] Alternatively, the freezing pipe may be vertically arranged in an S-shape on the first body and the second body.

[0012] Alternatively, the cryotube may comprise a copper tube.

[0013] Optionally, the number of the inlets may be one or more, and the inlets may extend outward from the upper end or the lower end of the freezing box body.

[0014] Optionally, the number of the outlets may be one or more, and the outlets may extend outward from the upper end or the lower end of the freezing box body.

[0015] Optionally, both ends of the first body and the second body may be provided with connecting plates.

[0016] Optionally, the first connecting assembly and the second connecting assembly may both include a plurality of matching bolts and nuts; and the connecting plate is provided with a plurality of through holes for the bolts to pass through.

[0017] Optionally, both the first body and the second body may be provided with auxiliary armrests.

[0018] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0019] (1) The freezer box of the present invention is a two-half structure. The two-half freezer box body can be tightly connected by a connecting plate through connecting bolts. The installation method is simple and quick, and only 2 to 3 operators and 6 to 7 minutes are needed to complete the installation.

[0020] (2) The auxiliary handrail of the utility model is not only convenient for installation of the two-half type freezer box body, but also convenient for transportation and loading and unloading.

[0021] (3) The copper tube of the utility model is vertically embedded in the two-half freezer box body in an "S" shape, and the temperature difference between the upper and lower parts of the freezing area does not exceed 5°C. The temperature in the freezing area is more balanced and the freezing effect is better.

[0022] (4) The utility model has two channels for the freezing process inlet and the freezing process outlet, and liquid nitrogen can perform freezing operations simultaneously through the two channels, thereby achieving rapid cooling of the freezing process and improving the efficiency of the freezing operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects and / or features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0024] Figure 1 A structural schematic diagram of a freezing box for treating hidden dangers at wellheads of oil and gas wells according to the utility model is shown.

[0025] Description of main reference numerals:

[0026] 11-first body, 12-second body; 21-inlet, 22-outlet, 23-copper tube; 3-connecting plate; 4-connecting bolt; 5-auxiliary handrail. DETAILED DESCRIPTION

[0027] Hereinafter, the freezing box for treating hidden dangers at the wellhead of an oil and gas well of the present invention will be described in detail in conjunction with exemplary embodiments.

[0028] It should be noted that "first", "second", "third", "fourth", etc. are only for the convenience of description and distinction, and should not be understood as indicating or implying relative importance. "Up", "down", "front", "back", "left", "right", "inside", "outside", etc. are only for the convenience of description and the formation of relative orientation or position relationship, and do not indicate or imply that the referred parts must have such specific orientation or position. For ordinary technicians in this field, some terms "pressure" in this article are equivalent to pressure.

[0029] Exemplary Embodiment 1

[0030] This exemplary embodiment relates to a freezing box used for treating hidden dangers at the wellhead of an oil and gas well in a pressure well repair process.

[0031] The freezing box may include a freezing box body, a freezing process and a connecting unit. The freezing box body is a two-half freezing box body, and includes a first body and a second body. The freezing process includes a freezing pipe, a freezing process inlet (which may be referred to as the inlet) and a freezing process outlet (which may be referred to as the outlet); the freezing pipe is arranged on the freezing box body; the inlet and the outlet are connected to the freezing pipe. The connecting unit includes a first connecting component and a second connecting component, which can respectively connect the two ends of the first body and the second body.

[0032] In this embodiment, the cross section of the cavity formed by the first body and the second body can be circular, elliptical or polygonal. As an option of the present invention, the freezing box body can be cylindrical, and the first and second bodies are semicircular arc plates. The first body and the second body can have the same shape and size.

[0033] In this embodiment, the first body and the second body can be connected by a connecting member, and the connecting member can include a matching bolt and nut. Of course, the present invention is not limited thereto, and other connecting members can also be used. Both ends of the first body and the second body are provided with a connecting plate for connection, and the connecting plate can be provided with a through hole.

[0034] In this embodiment, the cooling pipe can be embedded in the inner walls of the first body and the second body facing inwards, for example, by means of snap fastening. Of course, other methods can also be used for embedding.

[0035] In this embodiment, the freezing tube can be arranged on the first body and the second body in an S-shaped vertical or annular manner. Preferably, the freezing tube is vertically embedded in the two-half freezing box body in an S-shaped manner, the temperature difference between the upper and lower parts of the freezing area does not exceed 5°C, the temperature in the freezing area is more uniform, the freezing effect is better, there are two channels for the freezing process inlet and the freezing process outlet, and liquid nitrogen can have two channels for simultaneous freezing operations, so as to achieve rapid cooling of the freezing process, shorten the pre-freezing operation time, and improve the efficiency of the freezing operation.

[0036] The number of the freezing tubes may be at least 1, for example 2, 3, or 4. As an example, two freezing tubes are embedded in the inner wall of the body in an axial S-shaped form, and the positions of the two freezing tubes are staggered.

[0037] In this embodiment, the freezing pipe can be a copper pipe, but it is certainly not limited to this, and other pipe materials can also be used.

[0038] In this embodiment, the number of inlets and outlets is one or more, and both can extend outward from the upper end or lower end of the freezing box body to connect to the external process. Further, the number of inlets and outlets is the same and both are ≥2, such as 3, 4, etc.

[0039] In this embodiment, auxiliary armrests are provided on both the first body and the second body, which not only facilitate the installation of the two-half freezing box body, but also facilitate transportation and loading and unloading.

[0040] In order to better understand the above exemplary embodiments, they are further described below with reference to specific examples.

[0041] Example 1

[0042] Combine the following Figure 1 To describe the freezing box of this example for treating hidden dangers at the wellhead of an oil and gas well.

[0043] The freezing box comprises a freezing box body, an auxiliary handrail 5, a connecting plate 3, connecting bolts 4 and a freezing process.

[0044] The freezing box body is a two-half freezing box body, and includes a first body 11 and a second body 12. Both ends of the first body and the second body are provided with a connecting plate 3, and three through holes are opened on the connecting plate 3. There are six connecting bolts 4, three on each side, which are used to connect the first body 11 and the second body 12; specifically, the connecting bolts 4 pass through the through holes on the connecting plate 3 and are tightly connected by matching nuts.

[0045] The freezing process consists of an inlet 21, an outlet 22 and a copper tube 23. The copper tube 23 is vertically embedded in the first body 11 and the second body 12 in an "S" shape. The temperature difference between the upper and lower parts of the freezing area does not exceed 5°C, the temperature in the freezing area is more uniform, and the freezing effect is better. The copper tube 23 is connected to the external process through the inlet 21 and the outlet 22.

[0046] The inlet 21 and the outlet 22 have two channels, and liquid nitrogen can perform freezing operations simultaneously through the two channels, thereby achieving rapid cooling of the freezing process, shortening the pre-freezing operation time, and improving the freezing operation efficiency.

[0047] The two auxiliary handrails 5 are respectively arranged on the first body 11 and the second body 12, which is not only convenient for installation of the two-half type freezing box body, but also convenient for transportation and loading and unloading.

[0048] Although the present invention has been described above in conjunction with the exemplary embodiments and the accompanying drawings, it should be apparent to those skilled in the art that various modifications may be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A freezing box for treating hidden dangers at the wellhead of an oil and gas well, characterized in that: The freezing box includes a freezing box body, a freezing process and a connecting unit, wherein: The freezing box body has a hollow cavity and includes a first body and a second body; The freezing process includes a freezing pipe, an inlet and an outlet; wherein the freezing pipe is arranged on the first body and the second body; the inlet and the outlet are arranged on the freezing pipe, and are used for freezing materials to enter and exit the freezing pipe respectively; The connecting unit includes a first connecting component and a second connecting component, which can respectively connect two ends of the first body and the second body.

2. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1 is characterized in that: The cross section of the cavity is circular, elliptical or polygonal.

3. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: The freezing tube is embedded in the inward walls of the first body and the second body.

4. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: The freezing pipe is vertically arranged in an S shape on the first body and the second body.

5. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: The freezing pipe comprises a copper pipe.

6. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: The number of the inlets is one or more, and the inlets extend outward from the upper end or the lower end of the freezing box body.

7. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: The number of the outlets is one or more, and the outlets extend outward from the upper end or the lower end of the freezing box body.

8. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: Both ends of the first body and the second body are provided with connecting plates.

9. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 8, characterized in that: The first connecting assembly and the second connecting assembly both include a plurality of matching bolts and nuts; The connecting plate is provided with a plurality of through holes for bolts to pass through.

10. The freezing box for treating hidden dangers at the wellhead of an oil and gas well according to claim 1, characterized in that: Auxiliary handrails are arranged on the first body and the second body.

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