Wellhead sealing device for optical fiber long-term monitoring of high-pressure oil and gas well

Abstract

The invention discloses a wellhead sealing device for optical fiber long-term monitoring of a high-pressure oil and gas well, which can realize that a smooth optical cable penetrates through a wellhead to fix an underground optical cable, performs wellhead static sealing of optical fiber underground long-term monitoring, can monitor the pressure condition in each stage of sealing device in real time, ensures effective sealing, and performs emergency disposal under the leakage condition. The invention can also be used for underground monitoring wellhead sealing of smooth cables. Specifically, after a well-descending smooth optical cable penetrates through the rubber pier, the rubber pier tightly holds the well-descending optical cable under the extrusion of the gland and pressure from the interior of the well so as to achieve a static sealing effect. By arranging the lower blowout preventer connector on the outer wall of the sealing box body at one end of the downhole optical cable, the purpose of emergency well sealing under the leakage condition can be achieved, by installing the pressure wireless transmission module communicated with the interior of the sealing device on the connector, the pressure condition in each stage of sealing device can be monitored in real time, effective sealing is ensured, and the sealing effect is improved. And emergency disposal is carried out under the leakage condition.

Description

Technical Field

[0001] The invention belongs to the technical field of wellhead sealing, and relates to a wellhead sealing device used for long-term optical fiber monitoring of high-pressure oil and gas wells. Background Art

[0002] With the development of fiber optic monitoring technology, high-pressure oil and gas well long-term fiber optic monitoring technology has also been widely used. When conducting long-term fiber optic monitoring of high-pressure oil and gas wells, the optical fiber must remain in the well and remain suspended, and the upper end of the optical fiber must pass through the wellhead to connect with the data acquisition end. The long-term monitoring time of optical fiber is generally more than three months. It is required to ensure the sealing of the optical cable at the wellhead to meet the well control requirements and to be able to take emergency measures in case of emergency. The optical cable sealing devices used in the past cannot meet these new requirements. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the existing sealing devices in the prior art cannot ensure the sealing of the optical cable passing through the wellhead, cannot meet the well control requirements, and cannot perform emergency disposal in case of emergency, and provide a wellhead sealing device for long-term monitoring of optical fiber in high-pressure oil and gas wells.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention proposes a wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells, comprising a downhole optical cable;

[0006] A plurality of guide columns are sleeved on the downhole optical cable, and a rubber pier is provided between the downhole optical cable and the guide column; a sealing box body is provided on the outer wall of each guide column, and the plurality of sealing box bodies are connected by a connector; a gland and a lower blowout preventer connector are provided on the outer walls of the sealing box bodies at both ends of the downhole optical cable respectively; a pressure wireless transmission module connected to the inside of the sealing device is vertically installed on the connector.

[0007] Preferably, the lower blowout preventer connector includes a union and an integral union;

[0008] A union joint is arranged on the outer wall of the sealing box body at one end of the downhole optical cable, an end plug is arranged inside the union joint, a baffle ball and a baffle disc are arranged inside the end plug, and the downhole optical cable passes through the union joint, the end plug and the baffle ball in sequence and is connected with the baffle disc; the integral union is located outside the union joint.

[0009] Preferably, a first O-ring and a retaining ring are provided between the sealing box body and the gland, between the sealing box body and the connector, between the sealing box body and the union joint, and between the integral union and the union joint.

[0010] Preferably, a second O-ring is provided between the union and the end plug.

[0011] Preferably, the pressure wireless transmission module comprises a needle valve and a needle valve switch; the needle valve switch is mounted on the needle valve;

[0012] One end of the needle valve is connected to the connector, and the other end of the needle valve is connected to the three-way interface. The second port of the three-way interface is connected to a pressure sensor, and a data wireless transmitter is connected to the pressure sensor. The third port of the three-way interface is connected to a plug.

[0013] Preferably, the needle valve and the connector, as well as the needle valve and the three-way interface are connected via double male connectors.

[0014] Preferably, a grease nipple is provided between the three-way interface and the plug.

[0015] Preferably, an optical cable hanger is provided at the end of the gland.

[0016] Preferably, a sealing structure is provided outside the sealing box body.

[0017] Preferably, the other end of the lower blowout preventer connector is connected to a three-gate blowout preventer.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention proposes a wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells, which can realize the smooth optical cable passing through the wellhead to fix the downhole optical cable, perform static sealing of the wellhead for long-term optical fiber downhole monitoring, and can monitor the pressure conditions in each level of sealing devices in real time to ensure effective sealing and take emergency measures in case of leakage. The present invention can also be used for downhole monitoring wellhead sealing of smooth cables. Specifically, after the downhole smooth optical cable passes through the rubber pier, the rubber pier hugs the downhole optical cable under the pressure of the pressure cap and the pressure from the well to achieve a static sealing effect. By providing a lower blowout preventer connector on the outer wall of the sealing box body at one end of the downhole optical cable, the purpose of emergency sealing of the well can be achieved in case of leakage. By installing a pressure wireless transmission module connected to the downhole optical cable on the connector, the pressure conditions in each level of sealing devices can be monitored in real time to ensure effective sealing and take emergency measures in case of leakage.

[0020] Furthermore, the optical cable hanger can be provided to fix the downhole cable, thereby ensuring that the downhole optical cable will not move and fall into the well during long-term monitoring.

[0021] Furthermore, the lower blowout preventer connector is connected to the three-gate blowout preventer. If the optical cable wellhead static sealing device leaks during the monitoring process and the sealing component needs to be replaced, the two semi-sealed gates in the three-gate blowout preventer can be closed, and the sealing component can be replaced after the wellhead is sealed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a structural diagram of the optical cable long-term sealing device of the present invention.

[0024] Figure 2 This is an appearance diagram of the optical cable long-term sealing device of the present invention.

[0025] Figure 3 It is a top view of the long-term sealing device for optical cables of the present invention.

[0026] Figure 4 This is a wellhead installation diagram of the sealing device of the present invention.

[0027] Among them: 1- gland, 2- guide column, 3- rubber pier, 4- sealing box body, 5- connector, 6- union, 7- end plug, 8- overall union, 9- baffle ball, 10- baffle plate, 11- first O-ring, 12- baffle ring, 13- second O-ring, 17- double male connector, 18- needle valve, 19- three-way interface, 20- pressure sensor, 21- butter nipple, 22- optical cable hanger, 26- needle valve switch, 27- plug, 28- wireless data transmitter, 29- lower blowout preventer connector, 30- lower well optical cable, 32- three-gate blowout preventer, 33- wellhead conversion flange. 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[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 the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0035] The present invention proposes a wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells, such as Figures 1 to 4 As shown, it includes a downhole optical cable 30; a plurality of guide columns 2 are sleeved on the downhole optical cable 30, and a rubber pier 3 is provided between the downhole optical cable 30 and the guide column 2; a sealing box body 4 is provided on the outer wall of each guide column 2, and a plurality of sealing box bodies 4 are connected by a connector 5; a gland 1 and a lower blowout preventer connector 29 are provided on the outer walls of the sealing box bodies 4 at both ends of the downhole optical cable 30; a pressure wireless transmission module connected to the inside of the sealing device is vertically installed on the connector 5. The rubber pier must match the size of the downhole optical cable 30. After the downhole optical cable 30 passes through the rubber pier 3, the rubber pier 3 hugs the downhole optical cable 30 under the pressure of the gland 1 and the pressure from the well to achieve a static sealing effect.

[0036] Among them, the lower blowout preventer connector 29 includes a union 6 and an integral union 8; the outer wall of the sealing box body 4 at one end of the downhole optical cable 30 is provided with a union 6, an end plug 7 is provided inside the union 6, and a ball 9 and a baffle 10 are provided inside the end plug 7. The downhole optical cable 30 passes through the union 6, the end plug 7 and the ball 9 and is connected to the baffle 10 in sequence; the integral union 8 is located outside the union 6. The emergency full-sealed ball-blocking module composed of a Φ9.5mm baffle 9 and a baffle 10 of a matching size in the optical cable channel, when the downhole optical cable 30 is inserted into the channel, the baffle 9 will return to the ball chamber at the side position. If the downhole optical cable 30 is pulled out, the baffle 9 will enter the optical cable channel under the action of the pressure in the well, blocking the baffle 10 to seal the high-pressure fluid in the well, so as to achieve the purpose of emergency sealing of the well in case of leakage.

[0037] A first O-ring 11 and a retaining ring 12 are provided between the sealing box body 4 and the gland 1, between the sealing box body 4 and the connector 5, between the sealing box body 4 and the union 6, and between the integral union 8 and the union 6. A second O-ring 13 is provided between the union 6 and the end plug 7. The first O-ring 11, the retaining ring 12 and the second O-ring 13 are provided for achieving a good sealing effect.

[0038] The pressure wireless transmission module includes a needle valve 18 and a needle valve switch 26; the needle valve switch 26 is installed on the needle valve 18 to control the opening and closing of the needle valve 18; one end of the needle valve 18 is connected to the connector 5, and the other end of the needle valve 18 is connected to the three-way interface 19, the second port of the three-way interface 19 is connected to a pressure sensor 20, the pressure sensor 20 is connected to a data wireless transmitter 28, and the third port of the three-way interface 19 is connected to a plug 27. The needle valve 18 and the connector 5, and the needle valve 18 and the three-way interface 19 are connected through a double male connector 17. A grease nipple 21 is provided between the three-way interface 19 and the plug 27.

[0039] An optical cable hanger 22 is provided at the end of the gland 1 to fix the downhole cable 30, thereby ensuring that the downhole optical cable 30 will not move and fall into the well during long-term monitoring.

[0040] A sealing structure is provided on the outside of the sealing box body 4 to ensure that the entire structure is in a sealed state, thereby avoiding external interference during operation and affecting the detection accuracy.

[0041] The other end of the lower blowout preventer connector 29 is connected to a three-gate blowout preventer 32. The lower blowout preventer connector 29 is matched with the three-gate blowout preventer 32. If the optical cable wellhead static sealing device leaks during the monitoring process and the sealing component needs to be replaced, the two half-sealed gates in the three-gate blowout preventer 32 can be closed, and the lower blowout preventer connector 29 can be removed after sealing the wellhead to replace the sealing component.

[0042] The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells proposed by the present invention is used in the construction site for long-term optical fiber monitoring. The operation process is as follows:

[0043] Step 1: Shut down the well, replace the wellhead conversion flange 33, and install the three-gate blowout preventer 32.

[0044] Step 2: Lower the optical cable 30 into the monitoring well to the designed depth through a winch and a pulley.

[0045] Step 3: Close the two half-closed gates of the blowout preventer 32 and lock them, release the pressure to zero, remove the connecting buckle between the blowout preventer 32 and the blowout preventer, use a crane to lift the blowout preventer 20 cm, install a cable clamp on the upper end of the blowout preventer 32, fix the downhole optical cable 30, lay down the blowout preventer, and cut the optical cable at the predetermined calculated length above the cable clamp.

[0046] Step 4: In order, the optical cable 30 going downhole is passed through the optical cable hanger 22, the sealing box structure, the emergency full-sealing ball module, and the lower blowout preventer connector 29 in order.

[0047] Step 5: Install a cable fixing card on the upper part of the cable hanger 22, lift the cable fixing card with a crane, remove the cable fixing card on the blowout preventer 32, connect the wellhead sealing device with the three-gate blowout preventer 32, tighten the cable hanger 22, and fix the optical cable 30 in the well.

[0048] Step 6: Connect the uphole optical cable 30 to the acquisition end to monitor the downhole signal.

[0049] Step 7: Monitor the pressure conditions in each level of sealing device in real time through the pressure sensor 20 to ensure effective sealing and take emergency measures in case of leakage.

[0050] Therefore, the wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells proposed in the present invention can realize the smooth optical cable passing through the wellhead to fix the downhole optical cable, perform static sealing of the wellhead for long-term optical fiber downhole monitoring, and can monitor the pressure conditions in each level of sealing devices in real time to ensure effective sealing and perform emergency disposal in the event of leakage. The present invention can also be used for downhole monitoring wellhead sealing of smooth cables. To meet the well control requirements of wellhead sealing for long-term optical fiber monitoring of high-pressure oil and gas wells, and ensure well control safety during monitoring. The present invention can also be applied to downhole monitoring wellhead sealing of smooth cables.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells, It is characterized in that It includes a downhole optical cable (30); A plurality of guide columns (2) are sleeved on the downhole optical cable (30), and a rubber pier (3) is provided between the downhole optical cable (30) and the guide column (2); a sealing box body (4) is provided on the outer wall of each guide column (2), and a plurality of sealing box bodies (4) are connected by a connector (5); a gland (1) and a lower blowout preventer connector (29) are provided on the outer walls of the sealing box bodies (4) at both ends of the downhole optical cable (30); and a pressure wireless transmission module connected to the inside of the sealing device is vertically installed on the connector (5).

2. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 1, It is characterized in that The lower blowout preventer connector (29) comprises a union (6) and an integral union (8); A union joint (6) is provided on the outer wall of a sealing box body (4) at one end of a downhole optical cable (30), an end plug (7) is provided inside the union joint (6), a baffle ball (9) and a baffle plate (10) are provided inside the end plug (7), and the downhole optical cable (30) passes through the union joint (6), the end plug (7) and the baffle ball (9) in sequence and is connected to the baffle plate (10); the integral union (8) is located outside the union joint (6).

3. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 2, It is characterized in that A first O-ring (11) and a retaining ring (12) are provided between the sealing box body (4) and the pressure cover (1), between the sealing box body (4) and the connecting body (5), between the sealing box body (4) and the union joint (6), and between the integral union (8) and the union joint (6).

4. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 2, It is characterized in that A second O-ring (13) is provided between the union (6) and the end plug (7).

5. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 1, It is characterized in that The pressure wireless transmission module comprises a needle valve (18) and a needle valve switch (26); the needle valve switch (26) is mounted on the needle valve (18); One end of the needle valve (18) is connected to the connector (5), and the other end of the needle valve (18) is connected to the three-way interface (19). The second port of the three-way interface (19) is connected to a pressure sensor (20), and the pressure sensor (20) is connected to a data wireless transmitter (28). The third port of the three-way interface (19) is connected to a plug (27).

6. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 5, It is characterized in that The needle valve (18) and the connector (5), as well as the needle valve (18) and the three-way interface (19) are connected via double male connectors (17).

7. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 5, It is characterized in that A grease nipple (21) is provided between the three-way interface (19) and the plug (27).

8. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 1, It is characterized in that An optical cable hanger (22) is provided at the end of the gland (1).

9. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 1, It is characterized in that A sealing structure is provided on the outside of the sealing box main body (4).

10. The wellhead sealing device for long-term optical fiber monitoring of high-pressure oil and gas wells according to claim 1, It is characterized in that The other end of the lower blowout preventer connector (29) is connected to a three-gate blowout preventer (32).

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