A wellhead heating device and method for wells at or below 140 MPa

Abstract

The present invention provides a wellhead heating device and method for 140MPa and below, belonging to the field of natural gas gathering and transportation methods and devices. It includes a cylinder and an electric heater, and the electric heater is connected to one side of the outside of the cylinder; the cylinder is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group is horizontally arranged in the cylinder; the natural gas inlet and the natural gas outlet are respectively connected to the two ends of the heat exchange coil group; the heat exchange coil group is arranged in a serpentine shape from top to bottom, and the connecting part and the end of the heat exchange coil group extend outside the cylinder. The present invention arranges the heat exchange coil connection part outside the cylinder, breaking the limitations of the selection of traditional heat exchange coil materials, increasing the coil design pressure, and significantly improving the overall pressure bearing capacity of the device; the device can directly heat the high-pressure end natural gas and effectively prevent the formation of hydrates.

Description

Technical Field

[0001] The present invention belongs to the field of natural gas gathering and transportation methods and devices, and in particular relates to a wellhead heating device and method for wells at pressures of 140 MPa or less. Background Art

[0002] When natural gas wells are opened, throttling and pressure reduction are required. The temperature reduction caused by the Joule-Thomson effect during throttling will produce hydrates, causing freezing of valves, pipe fittings and other parts. Due to the limitations of design standards and specifications, the working pressure of conventional heating furnaces is generally lower than 40MPa, which is lower than the opening pressure of many gas wells. Therefore, the heating furnace is generally arranged after the throttling manifold. In the early stage of opening the well, the high-pressure section is injected with alcohol to prevent freezing. If the heating furnace can be arranged in the high-pressure section, heating first and then throttling can be achieved, which is of great significance to ensure the safe operation of the wellhead manifold. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a wellhead heating device and method for 140MPa and below. The purpose of the present invention is to avoid the traditional welded heat exchange coil structure, set the heat exchange coil connection part outside the cylinder, break the limitations of the traditional heat exchange coil material selection, increase the coil design pressure, and significantly improve the overall pressure bearing capacity of the device; enable the device to directly heat the high-pressure section natural gas and effectively prevent the formation of hydrates.

[0004] In order to solve the above technical problems, the present invention provides a wellhead heating device for 140MPa and below, comprising a cylinder and an electric heater, wherein the electric heater is connected to one side of the outside of the cylinder;

[0005] The cylinder is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group is horizontally arranged in the cylinder; the natural gas inlet and the natural gas outlet are respectively connected to the two ends of the heat exchange coil group;

[0006] The heat exchange coil group is arranged in a serpentine shape from top to bottom, and the connecting parts and ends of the heat exchange coil group both extend outside the cylinder.

[0007] Furthermore, the electric heater includes a first heater and a second heater, and the first heater and the second heater are both connected to the cylinder through a connecting flange.

[0008] Furthermore, the heat exchange coil group includes a first I-shaped flange group and a second I-shaped flange group arranged in parallel, the first I-shaped flange group and the second I-shaped flange group are connected, the first I-shaped flange group is connected to the natural gas inlet, the second I-shaped flange group is connected to the natural gas outlet, the natural gas inlet is also connected to an inlet short circuit, and the natural gas outlet is also connected to an outlet short circuit.

[0009] Furthermore, the first I-shaped flange group and the second I-shaped flange group each include a plurality of I-shaped flanges arranged in a serpentine shape from top to bottom, both ends of each of the I-shaped flanges are fixedly connected with elbows after passing through the cylinder, and adjacent I-shaped flanges are fixedly connected by connecting short circuits, and both ends of each connecting short circuit are respectively fixedly connected to the corresponding elbows; the upper end of the first I-shaped flange group and the upper end of the second I-shaped flange group are fixedly connected by the connecting short circuit.

[0010] Furthermore, a flat head is provided at the position where the I-shaped flange passes through the cylinder, a hole is opened on the flat head for the I-shaped flange to pass through the cylinder, and a sealing structure is also provided on the outer side of the flat head.

[0011] Furthermore, the sealing structure includes a fixed seal, a movable seal and a sealing ring; the fixed seal is fixed to the flat head through the I-flange, the movable seal is threadedly connected to the fixed seal through the I-flange, and the sealing ring is arranged between the fixed seal and the movable seal.

[0012] Furthermore, the sealing ring is made of a material that is not affected by temperature and is not easily damaged by repeated deformation.

[0013] The present invention also provides a wellhead heating method for pressures of 140 MPa and below, using the wellhead heating device for pressures of 140 MPa and below, comprising the following steps:

[0014] S1. Connect the wellhead heating device to the front end of the throttling manifold in the test production process;

[0015] S2, natural gas is input through the natural gas inlet, flows through the heat exchange coil group, and is output from the natural gas outlet;

[0016] S3, the cylinder is filled with a heat exchange medium, and the electric heater heats the heat exchange coil group by heating the heat exchange medium;

[0017] S4. The heated heat exchange coil group then exchanges heat with the natural gas.

[0018] Furthermore, the heat exchange process in step S4 is performed by heat conduction and heat convection.

[0019] The present invention provides a wellhead heating device and method for a pressure of 140 MPa or less, which has at least the following beneficial effects:

[0020] By setting the connecting part of the heat exchange coil outside the cylinder, the limitations of the selection of traditional heat exchange coil materials are broken, the design pressure of the coil is increased, and the overall pressure bearing capacity of the device is significantly improved; the device can directly heat the high-pressure section of natural gas and effectively prevent the formation of hydrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a front view of a wellhead heating device for a pressure of 140 MPa or less according to an embodiment of the present invention;

[0022] Figure 2 A side view of a wellhead heating device for a pressure of 140 MPa or less according to an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of a specific connection method of a heat exchange coil unit according to an embodiment of the present invention;

[0024] Figure 4 for Figure 1 An enlarged schematic diagram of the sealing structure;

[0025] Figure 5 is a schematic diagram of a movable seal;

[0026] Figure 6 This is a flow chart of a wellhead heating method for a pressure of 140 MPa or less according to an embodiment of the present invention;

[0027] In the figure: 1. electric heater; 2. connecting flange; 3. elbow; 4. I-shaped flange; 5. sealing structure; 6. flat head; 7. cylinder; 8. connecting short circuit; 9. inlet short circuit; 10. outlet short circuit; 11. movable seal; 12. sealing ring; 13. fixed seal; 14. heat exchange coil group; 14-1, first I-shaped flange group; 14-2, second I-shaped flange group. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In order to better understand the purpose, structure and function of the present invention, the wellhead heating device and method for 140MPa and below of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0032] Example 1

[0033] like Figure 1 As shown, the present invention is a wellhead heating device for 140MPa and below, comprising a cylinder 7 and an electric heater 1, wherein the electric heater 1 is connected to one side of the outside of the cylinder 7;

[0034] The cylinder 7 is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group 14 is horizontally arranged in the cylinder 7; the natural gas inlet and outlet are respectively connected to the two ends of the heat exchange coil group 14;

[0035] The heat exchange coil group 14 is arranged in a serpentine shape from top to bottom, and the connecting parts and ends of the heat exchange coil group 14 extend to the outside of the cylinder 7.

[0036] Example 2

[0037] like Figure 1 As shown, the present invention is a wellhead heating device for 140MPa and below, comprising a cylinder 7 and an electric heater 1, wherein the electric heater 1 is connected to one side of the outside of the cylinder 7;

[0038] The cylinder 7 is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group 14 is horizontally arranged in the cylinder 7; the natural gas inlet and outlet are respectively connected to the two ends of the heat exchange coil group 14;

[0039] The heat exchange coil group 14 is arranged in a serpentine shape from top to bottom, and the connecting parts and ends of the heat exchange coil group 14 extend to the outside of the cylinder 7.

[0040] The difference between this embodiment and embodiment 1 is that:

[0041] like Figure 1 , Figure 2 and Figure 3As shown, the heat exchange coil group 14 includes a first I-shaped flange group 14-1 and a second I-shaped flange group 14-2 arranged in parallel, the first I-shaped flange group 14-1 and the second I-shaped flange group 14-2 are connected, the lower end of the first I-shaped flange group 14-1 is connected to the natural gas inlet, the lower end of the second I-shaped flange group 14-2 is connected to the natural gas outlet, the natural gas inlet is also connected to an inlet short circuit 9, and the natural gas outlet is also connected to an outlet short circuit 10;

[0042] The electric heater 1 includes a first heater and a second heater, and the first heater and the second heater are both connected to the cylinder 7 through a connecting flange 2;

[0043] The first I-shaped flange group 14-1 and the second I-shaped flange group 14-2 both include a plurality of I-shaped flanges 4 arranged in a serpentine shape from top to bottom, and both ends of each of the I-shaped flanges 4 are fixedly connected with elbows 3 after passing through the cylinder body, and adjacent I-shaped flanges 4 are fixedly connected by connecting short-circuits 8, and both ends of each connecting short-circuit 8 are respectively fixedly connected to the corresponding elbows 3; the upper end of the first I-shaped flange group 14-1 and the upper end of the second I-shaped flange group 14-2 are fixedly connected by the connecting short-circuit 8.

[0044] Example 3

[0045] like Figure 1 As shown, the present invention is a wellhead heating device for 140MPa and below, comprising a cylinder 7 and an electric heater 1, wherein the electric heater 1 is connected to one side of the outside of the cylinder 7;

[0046] The cylinder 7 is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group 14 is horizontally arranged in the cylinder 7; the natural gas inlet and outlet are respectively connected to the two ends of the heat exchange coil group 14;

[0047] The heat exchange coil group 14 is arranged in a serpentine shape from top to bottom, and the connecting parts and ends of the heat exchange coil group 14 extend to the outside of the cylinder 7.

[0048] The difference between this embodiment and the above embodiments is that:

[0049] like Figure 1 , Figure 4 and Figure 5 As shown, a flat head 6 is provided at the position where the I-shaped flange 4 passes through the cylinder 7, and a hole is opened on the flat head 6 for the I-shaped flange to pass through the cylinder, and the diameter of the hole is slightly larger than the outer diameter of the I-shaped flange 4; a sealing structure 5 is also provided on the outer side of the flat head 6;

[0050] The sealing structure comprises a fixed seal 13, a movable seal 11 and a sealing ring 12; the fixed seal 13 is fixed to the flat head through the I-shaped flange, the fixed seal 13 is provided with an internal thread, the movable seal 11 is provided with an external thread, the movable seal 11 is threadedly connected to the fixed seal 13 through the I-shaped flange 4, the sealing ring 12 is provided between the fixed seal 13 and the movable seal 11, and the movable seal 11 and the fixed seal 13 are sealed by compressing and deforming the sealing ring 12;

[0051] The sealing surfaces between the I-shaped flange, the elbow 3 and the connecting short circuit 8 are all sealed with steel rings, and the inlet short circuit 9, the outlet short circuit 10 and the I-shaped flange 4 are all connected with bolts and sealed with steel rings;

[0052] The connection surfaces of the elbow 3, the connecting short circuit 8, the inlet short circuit 9, and the outlet short circuit 10 all adopt the same flange surface as the I-shaped flange 4, and their number can be calculated and selected according to the area required for heating; the elbow 3, the connecting short circuit 8, the inlet short circuit 9, the outlet short circuit 10 and the I-shaped flange 4 are all integrally forged, and their material is 30CrMo or a material with higher strength.

[0053] Embodiment 4:

[0054] like Figure 6 As shown, the present invention provides a wellhead heating method for 140MPa and below, using the above-mentioned 140MPa wellhead heating device, comprising the following steps:

[0055] S1. Connect the wellhead heating device to the front end of the throttling manifold in the test production process;

[0056] S2, natural gas is input through the natural gas inlet, flows through the heat exchange coil group, and is output from the natural gas outlet;

[0057] S3, the cylinder is filled with a heat exchange medium (liquid), and the electric heater heats the heat exchange coil group by heating the heat exchange medium;

[0058] S4. The heated heat exchange coil group then exchanges heat with the natural gas.

[0059] The heat exchange process in step S4 is carried out by heat conduction and heat convection. The heat exchange coil group 14 includes a first I-shaped flange group 14-1 and a second I-shaped flange group 14-2 arranged in parallel. The first I-shaped flange group 14-1 and the second I-shaped flange group 14-2 both include a plurality of I-shaped flanges 4 arranged in a serpentine shape from top to bottom. The electric heater heats the I-shaped flange 4 by heating the heat exchange medium (liquid) in the cylinder, and then the I-shaped flange 4 exchanges heat with the natural gas flowing therethrough.

[0060] The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. In the absence of contradiction, various embodiments may be combined with each other to form new embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A wellhead heating device for 140MPa and below, characterized in that: It comprises a cylinder and an electric heater, wherein the electric heater is connected to one side of the outside of the cylinder; The cylinder is also provided with a natural gas inlet and a natural gas outlet, and a heat exchange coil group is horizontally arranged in the cylinder; the natural gas inlet and the natural gas outlet are respectively connected to the two ends of the heat exchange coil group; The heat exchange coil group is arranged in a serpentine shape from top to bottom, and the connecting part and the end part of the heat exchange coil group both extend outside the cylinder; The heat exchange coil group includes a first I-shaped flange group and a second I-shaped flange group arranged in parallel, the first I-shaped flange group and the second I-shaped flange group are connected, the first I-shaped flange group is connected to the natural gas inlet, the second I-shaped flange group is connected to the natural gas outlet, the natural gas inlet is also connected to an inlet short circuit, and the natural gas outlet is also connected to an outlet short circuit; The first I-shaped flange group and the second I-shaped flange group each include a plurality of I-shaped flanges arranged in a serpentine shape from top to bottom, both ends of each I-shaped flange are fixedly connected with elbows after passing through the cylinder, adjacent I-shaped flanges are fixedly connected by connecting short circuits, and both ends of each connecting short circuit are fixedly connected to the corresponding elbows respectively; the upper end of the first I-shaped flange group is fixedly connected to the upper end of the second I-shaped flange group by the connecting short circuit; A flat seal is provided at the position where the I-shaped flange passes through the cylinder. A hole is provided on the flat seal for the I-shaped flange to pass through the cylinder. A sealing structure is also provided on the outer side of the flat seal.

2. The wellhead heating device for 140MPa and below according to claim 1 is characterized in that: The electric heater comprises a first heater and a second heater, and both the first heater and the second heater are connected to the cylinder through a connecting flange.

3. The wellhead heating device for 140MPa and below according to claim 1 is characterized in that: The sealing structure includes a fixed seal, a movable seal and a sealing ring; the fixed seal passes through the I-shaped flange and is fixed to the flat head, the movable seal passes through the I-shaped flange and is threadedly connected to the fixed seal, and the sealing ring is arranged between the fixed seal and the movable seal.

4. The wellhead heating device for 140MPa and below according to claim 3 is characterized in that: The sealing ring is made of a material that is not affected by temperature and is not easily damaged by repeated deformation.

5. A method for heating a wellhead at 140 MPa or less, using the wellhead heating device at 140 MPa or less according to any one of claims 1 to 4, characterized in that: The steps include: S1. Connect the wellhead heating device to the front end of the throttling manifold in the test production process; S2, natural gas is input through the natural gas inlet, flows through the heat exchange coil group, and is output from the natural gas outlet; S3, the cylinder is filled with a heat exchange medium, and the electric heater heats the heat exchange coil group by heating the heat exchange medium; S4. The heated heat exchange coil group then exchanges heat with the natural gas.

6. The wellhead heating method for 140 MPa and below according to claim 5, characterized in that: The heat exchange process in step S4 is performed by heat conduction and heat convection.

Images