While-drilling instrument lubricating system with compensation device and compensation method thereof

Abstract

The invention discloses a while-drilling instrument lubricating system with a compensation device. The problems that an existing while-drilling measurement instrument is poor in sealing reliability, and an executing mechanism works unstably are solved. The upper and lower ends of the system connector (11) are respectively connected with a compensation device and a lubricating system; the compensation device comprises a compensation device shell (1) and an actuating mechanism valve rod (2); a compensation device body protection cover (5) and a compensation device body (6) are arranged on the actuating mechanism valve rod; the compensation device body protection cover is fixedly connected with the compensation device body; the compensation device body protection cover is hermetically connected with the compensation device body, the compensation device shell and the actuating mechanism valve rod; and the upper end of the connector (11) is in threaded connection with a compensation device shell. According to the while-drilling instrument lubricating system with the compensation device, the normal-pressure design of the while-drilling instrument lubricating system is utilized, so that the lubricating compensation device unidirectionally moves towards the lubricating oil side under the action of external drilling fluid pressure, and the sealing reliability and the working stability of an executing mechanism are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of measurement while drilling technology in petroleum exploration, and particularly to a lubrication system for a drilling instrument with a compensation device and a compensation method thereof. Background Technology

[0002] Measurement while drilling (MWD) instruments are widely used in the oil drilling field. They can measure engineering parameters such as well inclination and azimuth, as well as geological parameters such as resistivity and gamma ray. These downhole measurement data are then transmitted to the surface for processing via communication signals. The lubrication system of the MWD instrument ensures the stable operation of the mechanical actuators that transmit communication signals. Chinese Patent 206205883U discloses a "piston-compensated pulse generator" that can balance internal and external pressures. Chinese Patent 205778839U discloses a "pressure balancing sealing device for a downhole pulse generator," which can achieve pressure balance between the inside and outside of the pulse generator. In the above cases, the balancing valve or piston moves towards the low-pressure side under the influence of pressure differential. Since the low-pressure side is in the drilling fluid environment and is affected by solid particles in the drilling fluid, the seal of the balancing valve or piston may fail when it moves towards the low-pressure side, potentially leading to the failure of the entire device. Summary of the Invention

[0003] This invention addresses the problems of poor sealing reliability and unstable operation of existing measurement-while-drilling (MWD) instruments by providing a MWD lubrication system with a compensation device. This MWD lubrication system utilizes the atmospheric pressure design of the MWD lubrication system, allowing the lubrication compensation device to move unidirectionally towards the lubricating oil side under external drilling fluid pressure, thus ensuring sealing reliability and actuator stability. This invention also provides a compensation method for the MWD lubrication system with the compensation device.

[0004] The present invention solves its problem through the following technical solution: the drilling instrument lubrication system with compensation device includes a connecting body, the upper and lower ends of which are respectively connected to the compensation device and the lubrication system; The compensation device includes a compensation device housing and an actuator valve stem. The actuator valve stem is equipped with a compensation device body protective cover and a compensation device body. The compensation device body protective cover is fixedly connected to the compensation device body. The compensation device body protective cover and the compensation device body are sealed to the compensation device housing and the actuator valve stem. The lower end of the connecting body is threaded to the compensation device housing.

[0005] Furthermore, the lubrication system includes a lubrication system housing, within which an actuator sliding rod is installed; the end of the actuator sliding rod is threadedly connected to an actuator transmission nut, and the upper end of the actuator sliding rod is threadedly connected to the actuator valve stem of a compensation device; an upper centering block and a lower centering block are respectively installed on the upper and lower parts of the actuator sliding rod; the lubrication system is threadedly connected to the upper end of the connecting body through the lubrication system housing.

[0006] Furthermore, the actuator sliding rod body is a stepped shaft-shaped rod body that is thinner at the top and thicker at the bottom; an axial center hole is opened in the center of the rod body; a keyway is radially opened in the middle of the actuator sliding rod body; an anti-rotation rod is installed between the keyway and the opposite connecting body, and the actuator sliding rod is anti-rotated by the anti-rotation rod; a cross hole is radially opened at the thin end of the actuator sliding rod body for the flow of lubricating oil in the cavity; a slot is opened at the thick end of the actuator sliding rod body, and the space between the slot at the thick end of the actuator sliding rod body and the actuator transmission nut is a lubricating oil chamber, and several oil holes are opened in the wall of the slot, through which lubricating oil enters the axial center hole inside the actuator sliding rod body; the top opening of the actuator sliding rod body faces the lubricating oil chamber.

[0007] Furthermore, the actuator transmission nut is threadedly connected to the actuator screw to achieve transmission.

[0008] Furthermore, an external seal is provided between the protective cover of the compensation device body and the compensation device body and the outer shell of the compensation device; an internal seal is provided between the protective cover of the compensation device body and the compensation device body and the valve stem of the actuator.

[0009] Furthermore, the actuator valve stem is threadedly connected to the lower end of the actuator sliding rod via a fastening nut.

[0010] Furthermore, a sealing ring is placed between the connector and the lubrication system housing and the compensation device housing.

[0011] Furthermore, the protective cover of the compensation device body is connected to the compensation device body by fixing screws.

[0012] The present invention also provides a compensation method for a lubrication system of a drilling instrument with a compensation device, comprising the following steps: The compensation device body and the compensation device body protective cover form a lubrication system compensation device through the sealing action of the compensation device shell and the inner and outer seals between the actuator valve stem. It utilizes the atmospheric pressure design of the drilling instrument lubrication system to make the internal pressure of the lubrication system lower than the external drilling fluid environment pressure. When the internal lubricating oil is lost in order to ensure the stable operation of the actuator, the lubrication system compensation device will move unidirectionally towards the lubrication system side under the action of the external drilling fluid pressure to compensate for the space generated by the lubricating oil loss. This ensures the reliability of the seal and the working stability of the lubrication system actuator, and is used to prevent the mixing of external drilling fluid and internal lubricating oil.

[0013] Furthermore, the lubrication system compensation device withstands a pressure of 20 MPa.

[0014] The present invention first installs the inner and outer seals on the compensation device body and the compensation device body protective cover to form the compensation device body assembly; then installs the assembly on the valve stem of the actuator; and then installs the formed mechanism together inside the compensation device housing to form a lubrication and sealing environment for the actuator, ensuring that the actuator works normally and stably in the lubrication and sealing environment.

[0015] Compared with the above-mentioned background technology, the present invention has the following beneficial effects: This invention relates to a compensation device with internal and external sealing grooves, used to seal the drilling fluid environment and the lubricating oil environment. This lubrication compensation device utilizes the atmospheric pressure design of the drilling instrument's lubrication system, ensuring that the internal pressure of the lubrication system is lower than the external drilling fluid environment pressure. When the internal lubricating oil is lost during stable operation of the actuator, the lubrication compensation device will move unidirectionally towards the lubricating oil side under the external drilling fluid pressure, compensating for the space lost due to lubricating oil loss.

[0016] This invention balances internal and external pressures and ensures the normal and stable operation of the lubrication system when the drilling instrument is working, while it can withstand pressures of up to 20 MPa. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure of the present invention.

[0018] In the diagram: 1. Compensation device housing; 2. Actuator valve stem; 3. Outer seal; 4. Inner seal; 5. Compensation device body protective cover; 6. Compensation device body; 7. Fixing screw; 8. Fastening nut; 9. Anti-rotation rod; 10. Actuator sliding rod; 11. Connecting body; 12. Lubrication system housing; 13. Actuator lead screw; 14. Actuator transmission nut; 15. Lower straightening block; 16. Upper straightening block. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0020] like Figure 1 As shown, a lubrication system for a drilling instrument with a compensation device includes a connector 11, the upper and lower ends of which are respectively connected to the compensation device and the lubrication system. The compensation device includes a compensation device housing 1 and an actuator valve stem 2. The actuator valve stem 2 is equipped with a compensation device body protective cover 5 and a compensation device body 6. The compensation device body protective cover 5 and the compensation device body 6 are threadedly connected by fixing screws 7. An outer seal 3 is placed between the compensation device body protective cover 5 and the compensation device body 6 and the compensation device housing 1. An inner seal 4 is placed between the compensation device body protective cover 5 and the compensation device body 6 and the actuator valve stem 2. The upper end of the connecting body 11 is threadedly connected to the compensation device housing 1.

[0021] The lubrication system includes a lubrication system housing 12, within which an actuator sliding rod 10 is installed. The lower end of the actuator sliding rod 10 is threadedly connected to an actuator transmission nut 14, and the upper end of the actuator sliding rod 10 is threadedly connected to the actuator valve stem 2 of the compensation device via a fastening nut 8. An upper regulating block 16 and a lower regulating block 15 are respectively installed on the upper and lower parts of the actuator sliding rod 10. The actuator transmission nut 14 is threadedly connected to an actuator lead screw 13 for transmission. The lubrication system is threadedly connected to the lower end of a connecting body 11 via the lubrication system housing 12.

[0022] The actuator sliding rod 10 has a stepped shaft-shaped rod body that is thinner at the top and thicker at the bottom; an axial center hole is opened in the center of the rod body; a keyway is radially opened in the middle of the actuator sliding rod body; an anti-rotation rod 9 is installed between the keyway and the opposite connecting body 11, and the actuator sliding rod 10 is anti-rotated by the anti-rotation rod 9; a cross hole is radially opened at the thinner end of the actuator sliding rod body for the flow of lubricating oil in the cavity; a slot is opened at the thicker end of the actuator sliding rod 10, and the space between the slot at the thicker end of the actuator sliding rod 10 and the actuator transmission nut 14 is a lubricating oil chamber. Three oil holes are opened in the wall of the slot, and lubricating oil enters the axial center hole inside the actuator sliding rod 10 through the oil holes; the bottom opening of the actuator sliding rod body faces the lubricating oil chamber.

[0023] The lubrication compensation process of a drilling instrument lubrication system with a compensation device is as follows: The actuator screw 13 rotates in both directions when there is no axial displacement, driven by an external micro motor. The external thread of the actuator screw 13 is connected to the internal thread of the actuator transmission nut 14, enabling the actuator transmission nut 14, actuator sliding rod 10, fastening nut 8, and actuator valve stem 2 to perform the actuator operation. Under the circumferential rotation limit action of the anti-rotation rod 9, it undergoes axial reciprocating movement. The lubricating oil lubricates the threads of the actuator screw 13 and actuator transmission nut 14, as well as the sliding mating surfaces of the actuator sliding rod 10 with the upper and lower regulating blocks 16 and 15. Lubricating oil enters the outer side of the actuator sliding rod 10 through the space formed by the outer surface of the actuator transmission nut 14 and the lubrication system housing 12. It then enters the axial center hole inside the actuator sliding rod 10 through three oil holes at the thicker end, and further enters the space formed by the actuator sliding rod 10, connecting body 11, upper centering block 16, and lower centering block 15 through the keyway hole, lubricating the outer surface of the actuator sliding rod 10. It also lubricates the connection between the actuator sliding rod 10 and the actuator valve stem 2 through the axial center hole inside the actuator sliding rod 10. Finally, lubricating oil enters the space formed by the compensating device body 6, compensating device housing 1, actuator valve stem 2, and actuator sliding rod 10 through the cross hole at the smaller end of the actuator sliding rod 10, lubricating the outer surface of the actuator valve stem 2. The fastening nut 8, anti-rotation rod 9, actuator sliding rod 10, actuator lead screw 13, actuator transmission nut 14, upper centering block 16, and lower centering block 15 are all within the lubricating environment of the lubricating oil. The space formed by the three parts of the compensation device housing 1, the actuator valve stem 2, and the compensation device body protective cover 5 is the external drilling fluid environment.

[0024] The compensation device body 6 and the compensation device body protective cover 5, through the sealing action of the inner and outer seals between the compensation device housing 1 and the actuator valve stem 2, respectively, form a lubrication system compensation device. Utilizing the atmospheric pressure design of the drilling instrument lubrication system, the internal pressure of the lubrication system is lower than the external drilling fluid environment pressure. When the internal lubricating oil is lost in order to ensure the stable operation of the actuator, the lubrication system compensation device will move unidirectionally towards the lubricating oil side under the action of the external drilling fluid pressure to compensate for the space generated by the lubricating oil loss. It can withstand a pressure of 20MPa, ensuring the reliability of the seal and the working stability of the lubrication system actuator, and is used to prevent the mixing of external drilling fluid and internal lubricating oil.

[0025] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A lubrication system for drilling instruments with a compensation device, comprising a connector (11), characterized in that: The upper and lower ends of the connector (11) are respectively connected to the compensation device and the lubrication system; The compensation device includes a compensation device housing (1) and an actuator valve stem (2). The actuator valve stem (2) is equipped with a compensation device body protective cover (5) and a compensation device body (6). The compensation device body protective cover (5) is fixedly connected to the compensation device body (6). The compensation device body protective cover (5) and the compensation device body (6) are sealed to the compensation device housing (1) and the actuator valve stem (2). The upper end of the connecting body (11) is threaded to the compensation device housing (1).

2. The drilling instrument lubrication system with a compensation device according to claim 1, characterized in that: The lubrication system includes a lubrication system housing (12), and an actuator sliding rod (10) is installed inside the lubrication system housing; the lower end of the actuator sliding rod (10) is threadedly connected to the actuator transmission nut (14), and the upper end of the actuator sliding rod is threadedly connected to the actuator valve stem (2) of the compensation device; an upper straightening block (16) and a lower straightening block (15) are respectively installed on the upper and lower parts of the actuator sliding rod; the lubrication system is threadedly connected to the lower end of the connector (11) through the lubrication system housing (12).

3. A lubrication system for drilling instruments with a compensation device according to claim 2, characterized in that: The actuator sliding rod (10) has a stepped shaft-shaped rod body that is thinner at the top and thicker at the bottom; an axial center hole is opened in the center of the rod body; a keyway is radially opened in the middle of the actuator sliding rod body; an anti-rotation rod (9) is installed between the keyway and the opposite connecting body (11), and the actuator sliding rod is anti-rotated by the anti-rotation rod; a cross hole is radially opened at the thin end of the actuator sliding rod body for the flow channel of lubricating oil in the cavity; a slot is opened at the thick end of the actuator sliding rod body, and the space between the slot at the thick end of the actuator sliding rod body and the actuator transmission nut is a lubricating oil chamber. Several oil holes are opened in the wall of the slot, and lubricating oil enters the axial center hole inside the actuator sliding rod body through the oil holes; the bottom opening of the actuator sliding rod body faces the lubricating oil chamber.

4. A drilling instrument lubrication system with a compensation device according to claim 2 or 3, characterized in that: The actuator transmission nut (14) is threadedly connected to the actuator screw (13) to achieve transmission.

5. A lubrication system for drilling instruments with a compensation device according to claim 1, characterized in that: An external seal (3) is provided between the protective cover (5) of the compensation device body and the compensation device body (6) and the outer shell (1) of the compensation device; an internal seal (4) is provided between the protective cover (5) of the compensation device body and the compensation device body (6) and the valve stem (2) of the actuator.

6. A lubrication system for drilling instruments with a compensation device according to claim 2, characterized in that: The actuator valve stem (2) is threadedly connected to the upper end of the actuator sliding rod (10) via a fastening nut (8).

7. A drilling instrument lubrication system with a compensation device according to claim 1 or 2, characterized in that: A sealing ring is placed between the connector (11) and the lubrication system housing (12) and the compensation device housing (1).

8. A lubrication system for drilling instruments with a compensation device according to claim 1, characterized in that: The protective cover (5) of the compensation device body is connected to the compensation device body (6) by fixing screws (7).

9. A compensation method for a drilling instrument lubrication system with a compensation device as described in any one of claims 1 to 8, characterized in that: Includes the following steps: The compensation device body and the compensation device body protective cover form a lubrication system compensation device through the sealing action of the compensation device shell and the inner and outer seals between the actuator valve stem. It utilizes the atmospheric pressure design of the drilling instrument lubrication system to make the internal pressure of the lubrication system lower than the external drilling fluid environment pressure. When the internal lubricating oil is lost in order to ensure the stable operation of the actuator, the lubrication system compensation device will move unidirectionally towards the lubrication system side under the action of the external drilling fluid pressure to compensate for the space generated by the lubricating oil loss. This ensures the reliability of the seal and the working stability of the lubrication system actuator, and is used to prevent the mixing of external drilling fluid and internal lubricating oil.

10. A lubrication system for drilling instruments with a compensation device according to claim 9, characterized in that: The lubrication system compensation device can withstand a pressure of 20MPa.

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