CN204200154U - Casing head - Google Patents

Abstract

The utility model provides a casing head, belonging to the field of coalbed methane well drilling, comprising a body, the middle part of the body is provided with a first through hole for embedding a production casing, and the body is divided into a smooth section and a threaded section connected to each other. A through hole runs through the smooth section and the threaded section, and the outside of the threaded section is provided with an external thread for threaded connection with the surface casing. The threaded section of the body is provided with an external thread, and an internal thread is provided on the inner side of the surface casing, and the external thread cooperates with the internal thread; firstly, the body is screwed so that the external thread of the threaded section of the body cooperates with the internal thread on the inside of the surface casing, and then Put the production casing into the first through hole, because the body and the surface casing are connected by threads, no welding and cutting operations are required, which avoids damage to the metallographic structure of the surface casing and effectively improves the strength of the surface casing ;During installation, only the body needs to be screwed into the surface casing, the installation time is short, the process is simple, the labor intensity of the construction personnel is reduced, and the production efficiency is improved.

Description

casing head

technical field

The utility model relates to the field of coal bed gas well drilling, in particular to a casing head.

Background technique

Coalbed methane refers to the hydrocarbon gas stored in coal seams with methane as the main component, mainly adsorbed on the surface of coal matrix particles, and partly free in coal pores or dissolved in coal seam water. It is an associated mineral resource of coal and belongs to very Conventional natural gas is a clean and high-quality new energy that has emerged internationally in the past ten or twenty years.

Coalbed methane is mainly exploited by ground drilling. The drilling of coalbed methane wells adopts a double-opening wellbore structure, and two layers of casing are lowered into the well. The surface casing is fixed by cementing outside the pipe, and the wellhead is suspended by a ring-shaped steel plate.

According to the characteristics of coalbed methane exploration and development, for the technical consideration of protecting the coal reservoir, when the production casing is cemented, the cement slurry is returned to 300m above the coal seam, and there is no cement outside the production casing from this position to the wellhead (called the free section casing). ), the free section casing is not fixed.

At present, the wellhead devices of coalbed methane wells all use annular steel plates to hang the production casing. During the installation process of the annular steel plates, operations such as cutting and welding are required to fix them on the surface casing. This method is easy to damage the metallographic structure of the surface casing. , greatly reducing the strength inside the surface casing.

Utility model content

The utility model provides a casing head, which improves the above problems.

The utility model is achieved in that:

A casing head, including a body. The middle part of the body is provided with a first through hole for embedding a production casing. The body is divided into a smooth section and a threaded section connected to each other. The first through hole runs through the smooth section and the threaded section, and the threaded section The outer side of the segment is provided with an external thread for threaded connection with the surface casing.

Further, at least one tubular side ear is provided on the outside of the body, and the side ear is provided with a third through hole, and the third through hole passes through the side wall of the body and communicates with the first through hole.

Due to the larger contact area of the threaded connection between the body and the surface casing, the sealing performance is better; the upper layer is blocked by the production casing, and the airtightness of the annular space between the surface casing and the production casing is better; the side ear The third through hole communicates with the first through hole, so that the cavity in the body can communicate with the outside world, so that a plug, a flat valve, a pressure gauge, etc. can be installed on the end of the third through hole far away from the first through hole. A kind of accessories, realize the functions of sealing the annular space between the surface casing and the production casing, testing the pressure of the annular space between the surface casing and the production casing, removing the gas in the annular space, and squeezing cement through the external circulation, etc. .

Further, the outer diameter of the threaded section is smaller than the outer diameter of the smooth section.

The threaded section and the inner side of the surface casing are threaded, and the outer diameter of the threaded section is roughly equal to the inner diameter of the surface casing; the outer diameter of the threaded section is smaller than the outer diameter of the smooth section, that is, the outer diameter of the smooth section is larger than that of the surface casing Inner diameter, when the threaded section is fully screwed into the surface casing, the end of the smooth section close to the threaded section is against the top of the surface casing, and the casing head cannot be further screwed so that its position is relatively fixed and the stability of the body is improved. enhanced.

Further, the body and the production casing are connected through a hanger, the hanger is embedded in the first through hole, the hanger is provided with a second through hole for accommodating the production casing, and the hanger is fixedly connected with the production casing.

The hanger can be used in conjunction with the main body to connect the main body and the production casing. Before the last production casing is placed, the hanger can be placed in the designated position and fixed with the production casing. During the fixing process, it can be pre-installed. Do a good job of sealing, and then lower the fixed production casing to realize the cooperation between the hanger and the body. The operation is simple and convenient; Compared with the main body, the structure is simpler, the production and replacement costs are lower, and there is no need to produce or replace different sizes of the main body, reducing production costs.

Further, the inner side of the second through hole is provided with an internal thread for threaded connection with the production casing.

Internal threads are set in the second through hole, and corresponding external threads are made on the production casing, so that a threaded connection is formed between the hanger and the production casing, the contact area between the hanger and the production casing is larger, and the sealing effect is improved. Better; the hanger and the main body are used in production together, and the sealing effect between the hanger and the main body can be controlled according to the needs, thereby controlling the sealing performance of the annular space between the surface casing and the production casing.

Further, at least two fourth through holes are provided on the side wall of the main body, and the first jacking wire is threaded in the fourth through hole, and the first jacking wire is threadedly connected with the fourth through hole, and one end of the first jacking wire abuts against the Hold the hanger.

After the production casing cementing is completed, when the landing section is disassembled at the wellhead (the landing section is connected to the last production casing when the production casing is lowered to adjust the position of the top surface of the production casing string and connected to the cement head short casing), the construction personnel need to stand under the drill floor and hold the chain tongs by hand. However, this fixing method is weak and unstable. Once the production casing is reversed, it will cause casualties due to mechanical damage, which is dangerous. Great sex. The undercut phenomenon refers to the phenomenon that two adjacent production casings are loosened or slipped due to the reverse rotation between two adjacent production casings because the production casing is composed of multiple casings connected by threads.

The body and the surface casing are connected by threads, and the hanger and the production casing are connected by threads. They are relatively fixed and difficult to move relative to each other. However, the body and the hanger are only surface-fitting and not fixed. Mechanism: The main body and the hanger are fixed by the first jacking wire. When the landing joint is disassembled, the relative rotation between the main body and the hanger cannot occur, so as to realize the connection between the surface casing, the main body, the hanger and the production casing. The stability of the production casing, that is, the position of the production casing relative to the surface casing is stable. Since the surface casing itself is fixed, the production casing will not be reversed, avoiding the occurrence of undercuts, and reducing the safety hazard when disassembling the landing joint; at the same time There is no need to manually hold the chain tongs, which reduces the labor intensity of construction personnel.

Further, a movable rod is provided on the top of the body, and the movable rod is rotatably connected with the body, and a groove for embedding the movable rod is provided at the part of the top of the hanger close to the body.

The cooperation between the movable rod and the groove has a similar effect on the first jacking wire, which is to fix the body and the hanger, so as to realize the stable position of the production casing relative to the surface casing, that is, the production casing will not reverse, avoiding the reverse The occurrence of buckle phenomenon reduces the potential safety hazard when disassembling the roof joint; at the same time, manual chain pliers are not needed, which reduces the labor intensity of construction workers; the fixing method of using movable rods and grooves is similar to that of using the first top screw The operation is much simpler than that, when fixing, you only need to turn the movable rod to snap it into the groove; the movable rod and the groove can be used together with the first jacking wire, or can be used separately. There are various ways in which the movable rod is rotatably connected to the body. For example, a rotating shaft may be provided on the body. The direction of the rotating shaft is perpendicular to the axis of the first through hole, and the movable rod rotates around the rotating shaft. Other rotary connections.

Further, a fifth through hole is provided on the side wall of the smooth section near one end of the threaded section, and a second jacking thread is threaded in the fifth through hole, and the second jacking thread is threadedly connected with the fifth through hole, and the second jacking thread One end of the wire is held against the production sleeve.

If there is no other fixing device, the relative rotation between the main body and the production casing is easy to occur, and the undercut phenomenon is easy to occur when the landing joint is disassembled; a second jacking wire is added to the smooth section, and the position of the production casing is fixed. The wire fixes the main body and the production casing, so as to realize the fixation between the production casing and the surface casing. When the landing joint is disassembled, the production casing will not follow the rotation of the landing joint to avoid the occurrence of undercutting. In addition, even after installing the first jacking wire to fix the main body and the hanger, since the hanger and the production casing are connected by threads, the production casing may still rotate with the landing joint, causing the production casing to slip off from the hanger If undercut occurs, the second top screw can completely avoid loosening or slipping of the threaded connection between the production casing and the hanger, reducing the chance of undercut.

Further, a bump is provided on the end of the smooth section close to the threaded section, and the bump is arranged on the outside of the surface sleeve, and a sixth through hole is arranged on the bump, and a third jacking wire is pierced in the sixth through hole, and the third jacking wire is pierced in the sixth through hole. The three top wires are threadedly connected with the sixth through hole, and one end of the third top wire is against the surface sleeve.

Due to the threaded connection between the body and the surface casing, under the action of external forces such as dismantling the landing joint, the body may still rotate relative to each other, causing it to loosen or slip off from the surface casing, thus causing the entire casing head and the production casing to break. Rotation, undercut phenomenon occurs, the third top screw can effectively improve this problem.

Further, the hanger is provided with a circular truncated section, the outer diameter of the circular truncated section gradually decreases from top to bottom, the outer surface of the circular truncated section is attached to the inner surface of the body, and the circular truncated section is provided with a metal sealing ring or a rubber sealing ring.

The surface casing and the main body, and the hanger and the production casing are threaded, and the sealing effect is relatively good, while the sealing effect is poor between the body and the hanger through lamination, and it is difficult to ensure that the surface casing The tightness of the annular space between the casing and the production casing; after adding metal sealing rings and rubber sealing rings, the sealing effect between the body and the hanger can be increased, so that the annular space between the surface casing and the production casing is completely The sealed state can avoid the problems of water leakage and air leakage caused by the use of annular steel plates as wellhead devices in coalbed methane wells, and ensure the safe and stable production of coalbed methane wells; the outer diameter of the circular platform section gradually decreases from top to bottom, and cannot Continue to descend, and the inclined surface can squeeze the metal sealing ring or rubber sealing ring to make the sealing effect better.

Compared with the prior art, the utility model has the beneficial effects that: the threaded section of the body is provided with an external thread, and an internal thread is provided on the inner side of the surface casing, and the external thread cooperates with the internal thread; firstly, the threaded section of the body is screwed. The external thread of the casing cooperates with the internal thread on the inner side of the surface casing, and then the production casing is placed in the first through hole, the two form a whole, and the production casing is fixed by the body. Since the body and the surface casing are connected by threads, welding and cutting operations are not required, which avoids damage to the metallographic structure of the surface casing and effectively improves the strength of the surface casing; only the body needs to be screwed into the surface casing during installation The installation time is short, the process is simple, the labor intensity of the construction personnel is reduced, and the production efficiency is improved.

Description of drawings

Fig. 1 is the top view of the casing head provided by Embodiment 1 of the present utility model;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is the front view of the casing head provided by Embodiment 2 of the present utility model;

Fig. 4 is the side view of Fig. 3;

Fig. 5 is the top view of Fig. 3;

Fig. 6 is the B-B sectional view of Fig. 5;

Fig. 7 is the axonometric view of Fig. 3;

Fig. 8 is a top view of the casing head provided by Embodiment 3 of the present invention;

FIG. 9 is a C-C sectional view of FIG. 8 .

Main body 101; production casing 102; first through hole 103; smooth section 104; threaded section 105; side ear 107; third through hole 108; Movable rod 113; groove 114; second top wire 115; bump 116; third top wire 117.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Fig. 1 is a top view of the casing head provided by Embodiment 1 of the utility model; Fig. 2 is a sectional view of A-A of Fig. 1 . As shown in Fig. 1 and Fig. 2, Embodiment 1 of the present utility model provides a casing head, which includes a body 101. The middle part of the body 101 is provided with a first through hole 103 in which a production casing 102 is embedded. A step is provided in the hole 103, and the step can block the production casing 102. The body 101 is divided into a smooth section 104 and a threaded section 105 that are connected to each other. The first through hole 103 runs through the smooth section 104 and the threaded section 105. The outer side of the threaded section 105 An external thread for threaded connection with the surface casing is provided.

The threaded section 105 of the body 101 is provided with an external thread, and an internal thread is provided on the inner side of the surface casing, and the external thread cooperates with the internal thread; firstly, the body 101 is screwed so that the external thread of the threaded section 105 of the body 101 and the internal thread on the inside of the surface casing The threads cooperate with each other, and then the production casing 102 is put into the first through hole 103 , the two form a whole, and the production casing 102 is fixed by the body 101 . Since the body 101 and the surface casing are connected by threads, no welding or cutting operations are required, which avoids damage to the metallographic structure of the surface casing and effectively improves the strength of the surface casing; only the body 101 needs to be screwed into the casing during installation. The surface casing is enough, the installation time is short, the process is simple, the labor intensity of the construction personnel is reduced, and the production efficiency is improved. The surface casing and production casing 102 are not part of the casing head, but are only used to describe the installation and use of the casing head.

Fig. 3 is a front view of the casing head provided by Embodiment 2 of the utility model; Fig. 4 is a side view of Fig. 3; Fig. 5 is a top view of Fig. 3; Fig. 6 is a B-B sectional view of Fig. 5; Fig. 7 is an axis of Fig. 3 Mapping. As shown in Figures 2-7, compared with Embodiment 1, the sleeve head provided by Embodiment 2 of the present utility model is improved in that two tubular side ears 107 are provided on the outside of the main body 101, and of course one or more than one Yes, the side ear 107 is provided with a third through hole 108 , and the third through hole 108 passes through the side wall of the body 101 and communicates with the first through hole 103 .

Due to the large contact area of the threaded connection between the body 101 and the surface casing, the sealing performance is better; the upper layer is blocked by the production casing 102, and the airtightness of the annular space between the surface casing and the production casing 102 is relatively high. Good; the third through hole 108 of the side ear 107 communicates with the first through hole 103, so that the cavity in the body 101 can communicate with the outside world, so that a wire can be installed at the end of the third through hole 108 away from the first through hole 103 plug, flat valve, pressure gauge and other accessories to seal the annular space between the surface casing and the production casing 102, test the pressure of the annular space between the surface casing and the production casing 102, and exclude the annular space The function of gas and cement injection through external circulation.

As a preferred solution of this embodiment, the outer diameter of the threaded section 105 is smaller than the outer diameter of the smooth section 104 .

The threaded section 105 is threadedly connected to the inner side of the surface casing, and the outer diameter of the threaded section 105 is approximately equal to the inner diameter of the surface casing; the outer diameter of the threaded section 105 is smaller than the outer diameter of the smooth section 104, that is, the outer diameter of the smooth section 104 greater than the inner diameter of the surface casing, when the threaded section 105 is completely screwed into the surface casing, the end of the smooth section 104 close to the threaded section 105 is against the top of the surface casing, and the casing head cannot continue to be screwed so that its position Relatively fixed, the stability of the main body 101 is enhanced.

As a preferred solution of this embodiment, the main body 101 and the production casing 102 are connected through a hanger 109, the hanger 109 is embedded in the first through hole 103, and the hanger 109 is provided with a second through hole for accommodating the production casing 102, A step is provided at the top of the second through hole, and the step is used to clamp the production casing 102 , and the hanger 109 is fixedly connected with the production casing 102 .

The hanger 109 can be used in conjunction with the main body 101 for connecting the main body 101 and the production casing 102. Before the last production casing 102 is placed, the hanger 109 can be placed in a designated position and connected to the production casing 102. Fixing, the sealing work can be done in advance during the fixing process, and then the fixed production casing 102 can be lowered to realize the cooperation between the hanger 109 and the body 101, and the operation is simple and convenient; in addition, the hanger 109 with different diameters can be replaced Compatible with production casings 102 of different diameters, the structure of the hanger 109 is simpler than that of the main body 101, and the manufacturing and replacement costs are lower. It is not necessary to produce or replace the main body 101 of different sizes, reducing production costs.

As a preferred solution of this embodiment, an inner thread for threaded connection with the production casing 102 is provided on the inner side of the second through hole.

Internal threads are set in the second through hole, and corresponding external threads are made on the production casing 102, so that a threaded connection is formed between the hanger 109 and the production casing 102, and the contact area between the hanger 109 and the production casing 102 Larger, better sealing effect; the hanger 109 is used in conjunction with the body 101 for production, and the sealing effect between the hanger 109 and the body 101 can be controlled as required, thereby controlling the annular space between the surface casing and the production casing 102 of tightness.

As a preferred solution of this embodiment, four fourth through holes are arranged on the side wall of the main body 101, and the four fourth through holes are evenly distributed around the main body 101, and the first top wire is pierced in the fourth through holes. 110 , the first jacking wire 110 is threadedly connected with the fourth through hole, and one end of the first jacking wire 110 is against the hanger 109 . An annular steel ring can also be arranged on the top of the body 101. The top surface of the annular steel ring is a flange plane, that is, several through holes are arranged around the axis line of the annular steel ring around the flange plane, and a cover flange is used on the top. To cover, the underside of the cover flange fits with the flange plane of the annular steel ring. The cooperation between the annular steel ring and the cover flange can facilitate the installation of other components or seal the internal space. An annular groove is arranged on the side wall of the body 101 located inside the annular steel ring, and a stopper can be provided inside the annular groove as required. The first jacking wire 110 runs through the annular steel ring, and the end of the first jacking wire 110 is located at In the annular groove, the end is located in the annular groove, and the stopper is used to limit the range of movement of the first jacking wire 110, so that it can move within a certain angle range, thereby controlling the rotation angle of the annular steel ring. The first jacking wire 110 cannot continue to move after resisting the block, that is, the annular steel ring cannot continue to rotate, thereby preventing the production casing 102 from being buckled.

After the production casing 102 cementing is completed, when the landing section is disassembled at the wellhead (the landing section is connected to the last production casing 102 when the production casing 102 is lowered to adjust the position of the top surface of the production casing 102 column, and The short casing connected to the cement head), the construction personnel need to stand under the drill floor and hold the chain tongs by hand. However, this fixing method is weak and unstable. Once the production casing 102 is undercut, it will cause mechanical damage. Causing personal injury or death is extremely dangerous. The undercut phenomenon refers to the phenomenon that two adjacent production casings 102 are loosened or slipped due to the reverse rotation between two adjacent production casings 102 due to the production casing 102 is composed of multiple casings connected by threads.

The body 101 and the surface casing are connected by threads, and the hanger 109 and the production casing 102 are connected by threads. They are relatively fixed to each other, and it is difficult for relative movement to occur. However, the body 101 and the hanger 109 are only surface-mounted. There is no fixing mechanism; the main body 101 and the hanger 109 are fixed by the first jacking wire 110. When the landing joint is disassembled, the relative rotation between the main body 101 and the hanger 109 cannot occur, thereby realizing the surface casing, The stability between the main body 101, the hanger 109 and the production casing 102, that is, the position of the production casing 102 relative to the surface casing is stable, because the surface casing itself is fixed, so that the production casing 102 will not reverse and avoid undercutting The occurrence of the phenomenon reduces the potential safety hazard when disassembling the joint top joint; at the same time, it does not need manual chain tongs, which reduces the labor intensity of construction personnel.

As a preferred solution of this embodiment, the hanger 109 is provided with a circular truncated section, the outer diameter of the circular truncated section gradually decreases from top to bottom, the outer surface of the circular truncated section fits the inner surface of the body 101, and the circular truncated section is provided with a metal sealing ring 111 and rubber sealing ring 112.

The surface casing and the main body 101, and the hanger 109 and the production casing 102 are threaded, and the sealing effect is relatively good, while the sealing effect is poor between the main body 101 and the hanger 109 through bonding. It is difficult to ensure the tightness of the annular space between the surface casing and the production casing 102; after adding the metal sealing ring 111 and the rubber sealing ring 112, the sealing effect between the body 101 and the hanger 109 can be increased, so that the surface casing and the The annular space between the production casings 102 is in a completely sealed state, avoiding the problems of water leakage and gas leakage caused by using the annular steel plate as the wellhead device in the coalbed methane well, and ensuring the safe and stable production of the coalbed methane well; the outer diameter of the circular table section is from top to The bottom gradually decreases, and cannot continue to descend after being attached to the body 101, and the inclined surface can squeeze the metal sealing ring 111 or the rubber sealing ring 112, so that the sealing effect is better.

Fig. 8 is a top view of the casing head provided by Embodiment 3 of the present utility model; Fig. 9 is a C-C sectional view of Fig. 8 . As shown in Figure 8 and Figure 9, compared with Embodiment 2, the casing head provided by Embodiment 3 of the present utility model has the improvement that: a movable rod 113 is arranged on the top of the body 101, and the movable rod 113 is rotationally connected with the body 101. The part of the top of the hanger 109 close to the body 101 is provided with a groove 114 for embedding the movable rod 113 .

The cooperation of the movable rod 113 and the groove 114 has a similar effect on the first jacking wire 110, both of which fix the body 101 and the hanger 109, so as to realize the stable position of the production casing 102 relative to the surface casing, that is, the production casing 102 It will not reverse, avoid the occurrence of undercut phenomenon, and reduce the safety hazard when disassembling the landing joint; at the same time, it does not need manual chain pliers, which reduces the labor intensity of construction workers; the fixing method of using the movable rod 113 and the groove 114 is the same as Compared with the fixing method using the first jacking wire 110, the operation is simpler. When fixing, only the movable rod 113 needs to be rotated to snap into the groove 114; the movable rod 113 and the groove 114 can be connected with the first jacking wire 110 can be used at the same time, or they can be used separately. The movable rod 113 is rotationally connected with the body 101 in various ways. For example, a rotating shaft may be provided on the main body 101. The direction of the rotating shaft is perpendicular to the axis line of the first through hole 103, and the movable rod 113 rotates around the rotating shaft. Of course, other rotational connection methods are also possible.

As a preferred solution of this embodiment, a fifth through hole is provided on the side wall of the smooth section 104 near one end of the threaded section 105, and a second jacking thread 115 is pierced in the fifth through hole, and the second jacking thread 115 and the second jacking thread 115 are connected to each other. The five through holes are threadedly connected, and one end of the second jacking wire 115 is against the production casing 102 .

If there is no other fixing device, the relative rotation between the body 101 and the production casing 102 is easy to occur, and the undercut phenomenon is easy to occur when the landing joint is disassembled; the second jacking wire 115 is added to the smooth section 104, and the production casing 102 is fixed. , using the second jacking wire 115 to fix the main body 101 and the production casing 102, so as to realize the fixation between the production casing 102 and the surface casing, when the landing joint is disassembled, the production casing 102 will not follow the landing joint to rotate, Avoid the occurrence of buckling phenomenon. In addition, even after installing the first jacking wire 110 to fix the main body 101 and the hanger 109, because the threaded connection between the hanger 109 and the production casing 102 is used, the production casing 102 may still follow the rotation of the landing joint, resulting in production failure. When the casing 102 slips from the hanger 109 and the like occurs undercutting, the second jacking screw 115 can completely prevent the threaded connection between the production casing 102 and the hanger 109 from loosening or slipping off, thereby reducing the probability of undercutting.

As a preferred solution of this embodiment, one end of the smooth section 104 close to the threaded section 105 is provided with a bump 116, the bump 116 is arranged on the outside of the surface sleeve, and the bump 116 is provided with a sixth through hole, the sixth through hole A third jacking thread 117 is threaded inside, and the third jacking thread 117 is threadedly connected with the sixth through hole, and one end of the third jacking thread 117 is against the surface casing.

Due to the threaded connection between the body 101 and the surface casing, under the action of external forces such as dismantling the landing joint, the body 101 may still rotate relative to it and cause it to loosen or slip off from the surface casing, so that the entire casing head and production sleeve The tube 102 rotates, resulting in an undercut phenomenon, and the third jacking wire 117 can effectively improve this problem.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (10)

1. A casing head, characterized in that, comprising: A body, the middle part of the body is provided with a first through hole for embedding a production casing, the body is divided into a smooth section and a threaded section connected to each other, and the first through hole runs through the smooth section and the threaded section segment, and the outside of the threaded segment is provided with an external thread for threaded connection with the surface casing. 2. The casing head according to claim 1, wherein at least one tubular side ear is provided on the outside of the body, and the side ear is provided with a third through hole, and the third through hole runs through the body and communicate with the first through hole. 3. The casing head of claim 1, wherein the outside diameter of the threaded section is smaller than the outside diameter of the smooth section. 4. The casing head according to claim 1, wherein the main body is connected to the production casing through a hanger, the hanger is embedded in the first through hole, and the hanger A second through hole for accommodating the production casing is provided, and the hanger is fixedly connected with the production casing. 5 . The casing head according to claim 4 , wherein an internal thread for threaded connection with the production casing is provided on the inner side of the second through hole. 5 . 6. The casing head according to claim 4, characterized in that at least two fourth through holes are provided on the side wall of the body, and the first jacking wire is pierced in the fourth through holes, so that The first jacking wire is threadedly connected to the fourth through hole, and one end of the first jacking wire is against the hanger. 7. The casing head according to any one of claims 4-6, characterized in that, the top end of the body is provided with a movable rod, the movable rod is rotatably connected with the body, and the top end of the hanger is close to A part of the body is provided with a groove for embedding the movable rod. 8. The casing head according to any one of claims 1-6, wherein a fifth through hole is provided on the side wall of the smooth section near the end of the threaded section, and the fifth through hole is A second jacking wire is threaded in the hole, and the second jacking wire is threadedly connected with the fifth through hole, and one end of the second jacking wire is against the production casing. 9. The casing head according to any one of claims 1-6, characterized in that, one end of the smooth section close to the threaded section is provided with a bump, and the bump is arranged on the surface casing On the outer side of the bump, a sixth through hole is provided on the bump, and a third jacking wire is pierced in the sixth through hole, and the third jacking wire is threadedly connected with the sixth through hole. One end of the top wire is against the surface sleeve. 10. The casing head according to any one of claims 4-6, wherein the hanger is provided with a truncated circular section, the outer diameter of the truncated circular section gradually decreases from top to bottom, and the truncated circular section The outer surface is attached to the inner surface of the body, and a metal sealing ring or a rubber sealing ring is arranged on the circular platform section.