Passive angle measurement composite mud pulse generator based on SMA (Shape Memory Alloy) driving

Abstract

The invention provides a tool applied to the field of oil and gas exploitation, and particularly relates to a passive angle measurement composite mud pulse generator based on SMA driving. Comprising an upper connector, a gravity valve block, a coding flow channel, a fixing groove, a sealing plate, a reset spring, a blanking plug, an SMA spring, a converging flow channel, a mounting cylinder, a driving frame, a heating driving unit, a control unit, a communication unit, a power supply unit cover plate, a lower connector, a locking nut, a clamping spring and a locking nut. By utilizing a gravity tool face angle passive measurement method and the characteristics of thermally induced deformation and small structure of shape memory alloy, a tool face angle mud pulse signal is passively generated through the coding flow channel and the gravity valve block, and then the blanking plug is driven by the SMA spring to sequentially plug flow channel holes to form a composite mud pulse signal, so that the size is small, the power consumption is low, and the cost is low. The device adapts to the underground high-temperature and high-pressure complex working environment, multi-parameter synchronous transmission can be achieved, and the reliability of measurement while drilling and the data transmission efficiency are improved.

Description

Technical Field

[0001] This invention is applicable to the field of oil and gas extraction, and specifically relates to a passive angle-measuring composite mud pulse generator based on SMA drive. Background Technology

[0002] In directional drilling of oil and gas, measurement while drilling (MWD) is the core means to ensure precise control of the drilling trajectory and real-time acquisition of downhole conditions and formation parameters. Among these technologies, mud pulse generators are the most widely used wireless data transmission technology. This technology generates pulse signals by modulating the pressure changes of the drilling mud in the drill string, transmitting key parameters such as tool face angle to the surface. This provides data support for drill bit orientation correction, formation evaluation, and drilling safety early warning, and its reliability directly determines the efficiency and accuracy of directional drilling.

[0003] Existing mud pulse generators mostly rely on motors, solenoid valves, or hydraulic components for their drive mechanisms. Their inherent technical defects are difficult to overcome. The supporting mechanisms are bulky and consume a lot of power, which limits their use in drilling scenarios such as small wells. Under the high temperature and high pressure conditions downhole, the reliability of the transmission components is difficult to guarantee. Moreover, they generally lack multi-parameter composite coding capabilities and most can only transmit a single navigation parameter, resulting in low signal transmission efficiency and poor anti-interference.

[0004] For the reasons mentioned above, it is of great significance to develop a mud pulse generator that provides stable and reliable measurements with diverse and clear data. Gravity tool face angle passive measurement has the characteristics of stable signal and adaptability to high temperature and high pressure working environment. Shape memory alloy (SMA) has the characteristics of thermal deformation and compact structure. Based on the passive measurement of tool face angle, it can be used as a driving element to perform composite encoding of mud pulse signal, providing a unique design idea for drilling measurement. Summary of the Invention

[0005] The purpose of this invention is to propose a passive angle-measuring composite mud pulse generator based on SMA drive. It passively generates tool face angle mud pulse signals through an encoded flow channel and a gravity valve block, and then uses an SMA spring to drive a blocker to block the flow channel holes in sequence to form a composite mud pulse signal.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: the passive angle measurement composite mud pulse generator based on SMA drive includes a passive angle measurement assembly, a composite encoding assembly, and an autonomous control assembly; The passive angle measurement assembly includes an upper connector, a gravity valve block, an coded flow channel, a junction channel, a mounting cylinder, a drive frame, a lower connector, a locking nut, a snap ring, and a locking nut. The coded flow channel is threadedly connected and fixed to the upper connector. The coded flow channel rotates with the drill string. The coded flow channel has regularly distributed flow channel holes and grooves of different sizes. The gravity valve block is axially fixed to the coded flow channel by the locking nut. The gravity valve block has an eccentric block pointing in the direction of gravity. The eccentric block is close to the coded flow channel. When the coded flow channel rotates with the drill string, the gravity valve block always points in the direction of gravity. The eccentric block sequentially blocks different flow channel holes, causing the drilling mud pressure to fluctuate periodically. By filtering and interpreting the pressure fluctuations of the drilling mud on the surface, the angle of tool rotation can be calculated, thus realizing passive angle measurement. The composite coding assembly includes a fixed groove, a sealing plate, a return spring, a plug, and an SMA spring. The fixed groove is fixed to the coding channel by screws, and the sealing plate is fixed to the fixed groove by screws. The fixed groove has a wire groove, and the wire is installed in the wire groove. The plug has a pressure plate and a hole. The return spring is installed in the hole and connects the sealing plate and the plug. The SMA spring is insulated and wired to the heating drive unit. When the SMA spring is heated to the phase change temperature, it will contract. The SMA spring is installed between the fixed groove and the pressure plate. In the reset state, the return spring returns to the compressed state, causing the SMA spring to stretch. In the trigger state, the heating drive unit heats the SMA spring to the phase change temperature, the SMA spring contracts, the return spring is stretched, and the plug moves down to block the flow channel hole, reducing the flow channel hole area by half, forming a pressure-locking effect, thereby achieving composite coding based on passive angle measurement. The autonomous control assembly includes a heating drive unit, a control unit, a communication unit, and a power supply unit. The control unit can control the heating drive unit to output different currents to heat the SMA spring, thereby controlling the blocker to block or reset. The communication unit is responsible for receiving other signals measured while drilling, and the power supply unit provides power. The composite coding assembly consists of 6 groups, which are evenly installed in the grooves of the coding channel. Each group of composite coding assemblies acts on one channel hole. The control unit controls the 6 groups of composite coding assemblies to block the channel holes in a regular manner, modulating the signal on the peak value and peak period of the drilling mud pressure, thereby generating a composite signal based on passive angle measurement.

[0007] As a further technical solution of the present invention, the upper connector and the lower connector are connected by threads, the manifold and the coding channel are connected by screws, the drilling mud flows out from each channel hole and is collected in the manifold, the manifold has protrusions and is positioned and installed with the coding channel, the spline groove on the manifold and the spline inside the mounting cylinder are circumferentially fixed, the manifold and the mounting cylinder are axially fixed by locking nuts, the mounting cylinder is connected to the drive frame by screws, the heating drive unit is installed in the mounting port of the drive frame, the control unit, the communication unit and the power supply unit are installed on the mounting cylinder and fixed by snap rings, and all installations are sealed.

[0008] As a further technical solution of the present invention, the diameter of the flow channel hole is distributed clockwise from the 6 o'clock position as "small-medium-large-small-large-medium". The gravity valve block always points to the gravity direction and is located at the 6 o'clock position. When the coded flow channel rotates one revolution, the gravity valve block blocks the flow channel hole in turn, corresponding to the pressure change in turn as "small-medium-large-small-large-medium". This is one cycle. After multiple revolutions and stopping, the tool face angle can be measured by the pressure change cycle and the pressure amplitude of the last revolution.

[0009] Compared with the prior art, the beneficial effects of the present invention are: 1. By using the gravity valve block and the coded flow channel to passively measure the tool face angle, it can adapt to the complex downhole working environment of high temperature and high pressure, and has good stability and reliability.

[0010] 2. By using an SMA spring-driven blocker to block the flow channel hole, composite encoding is achieved based on passive angle measurement, enabling multi-dimensional signal transmission and improving signal transmission efficiency.

[0011] 3. By adopting a passive angle measurement and SMA spring drive, compared with mud pulse generators driven by motors, solenoid valves and other mechanisms, the integration and reliability of the drive mechanism are greatly optimized, making it suitable for small-diameter drilling scenarios. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the inner layer of the present invention; Figure 3 Isometric view of gravity valve block; Figure 4 Isometric view of the coded flow channel; Figure 5 This is a schematic diagram of the flow channel hole distribution; Figure 6 Isometric view of the plug; Figure 7 Axonometric drawing of the interchange; Figure 8 Isometric drawing for installation cylinder; Figure 9 Axonometric drawing of the drive frame; Figure 10 This is a schematic diagram of a mud pulse signal; The markings in the diagram are as follows: 1-Upper connector, 2-Gravity valve block, 3-Encoded flow channel, 4-Fixing groove, 5-Sealing plate, 6-Reset spring, 7-Blocker, 8-SMA spring, 9-Connecting channel, 10-Mounting cylinder, 11-Drive frame, 12-Heating drive unit, 13-Control unit, 14-Communication unit, 15-Power supply unit cover plate, 16-Lower connector, 17-Locking nut, 18-Snap ring, 19-Locking nut. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are only a part of the present invention, and not all of it. Other embodiments obtained by those skilled in the art based on these embodiments without creative effort are also within the protection scope of the present invention.

[0014] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 The coded flow channel 3 is threadedly connected and fixed to the upper connector 1. The coded flow channel 3 rotates with the drill string. The coded flow channel 3 has flow channel holes 301 and grooves 302 of different sizes evenly distributed in a regular manner. The gravity valve block 2 is axially fixed to the coded flow channel 3 by locking nut 19. The gravity valve block 2 has an eccentric block 201 pointing in the direction of gravity. The eccentric block 201 is close to the coded flow channel 3. When the coded flow channel 3 rotates with the drill string, the gravity valve block 2 always points in the direction of gravity. The eccentric block 201 sequentially blocks different flow channel holes 301, so that the pressure of the drilling mud forms a periodic fluctuation. The ground can filter and interpret the pressure fluctuation of the drilling mud to calculate the angle of tool rotation, realizing passive angle measurement. Reference Figure 1 , Figure 2 , Figure 6 The fixed groove 4 is fixed to the coding channel 3 by screws, and the sealing plate 5 is fixed to the fixed groove 4 by screws. The fixed groove 4 has a wire groove 401, and the wire is installed in the wire groove 401. The blocker 7 has a pressure plate 701 and a hole 702. The reset spring 6 is installed in the hole 702 and connects the sealing plate 5 and the blocker 7. The SMA spring 8 is insulated and is wired to the heating drive unit 12. When the SMA spring 8 is heated to the phase change temperature, it will contract. The SMA spring 8 is installed between the fixed groove 4 and the pressure plate 701. In the reset state, the reset spring 6 returns to the compressed state, which drives the SMA spring 8 to stretch. In the trigger state, the heating drive unit 12 heats the SMA spring 8 to the phase change temperature. The SMA spring 8 contracts, the reset spring 6 is stretched, and the blocker 7 moves down to block the channel hole 301. The area of ​​the channel hole 301 is reduced by half, forming a pressure-locking effect, thereby achieving composite coding based on passive angle measurement. Reference Figure 1The control unit 13 can control the heating drive unit 12 to output different currents to heat the SMA spring 8, thereby controlling the blocker 7 to block or reset. The communication unit 14 is responsible for receiving other signals measured while drilling, and the power supply unit 15 provides power. Reference Figure 1 The composite coding assembly consists of 6 groups, which are evenly installed in the groove 302 of the coding channel 3. Each group of composite coding assembly acts on a channel hole 301. The control unit 13 controls the 6 groups of composite coding assemblies to block the channel holes 301 in a regular manner, modulating the signal on the peak value or peak period of the drilling mud pressure, thereby generating a composite signal based on passive angle measurement.

[0015] Reference Figure 1 , Figure 4 , Figure 7 , Figure 8 , Figure 9 The upper connector 1 and the lower connector 16 are connected by threads. The confluence channel 9 and the coding channel 3 are connected by screws. Drilling mud flows out from each channel hole 301 and converges into the confluence channel 9. The confluence channel 9 has a protrusion 901 that is positioned and installed with the coding channel 3. The spline groove 902 on the confluence channel 9 is circumferentially fixed to the spline 1001 inside the mounting cylinder 10. The confluence channel 9 and the mounting cylinder 10 are axially fixed by a locking nut 17. The mounting cylinder 10 is connected to the drive frame 11 by screws. The heating drive unit 12 is installed in the mounting port 1101 of the drive frame 11. The control unit 13, the communication unit 14 and the power supply unit 15 are installed on the mounting cylinder 10 and fixed by a snap ring 18. All installations are sealed.

[0016] Reference Figure 3 , Figure 4 , Figure 5 The diameter of the flow channel hole 301 is distributed clockwise from the 6 o'clock position as "small-medium-large-small-large-medium". The gravity valve block 2 always points to the gravity direction and is located at the 6 o'clock position. When the coded flow channel 3 rotates one revolution, the gravity valve block 2 blocks the flow channel hole 301 in sequence, corresponding to the pressure change in sequence as "small-medium-large-small-large-medium". This is one cycle. After multiple revolutions and stopping, the angle of tool rotation can be measured by the pressure change cycle and the pressure amplitude of the last revolution.

[0017] Reference Figure 10In one specific embodiment, a passive angle-measuring composite mud pulse generator driven by SMA is lowered into the well along with the measurement-while-drilling (MWD) equipment. During drilling, the mud pump is activated to deliver mud, and the wellhead mud pressure is monitored on the surface. As the equipment continues to drill, the drill string drives the SMA-driven passive angle-measuring composite mud pulse generator to rotate. The coded flow channel 3 rotates with the drill string, and the gravity valve block 2 remains in the direction of gravity. The flow channel holes 301 are sequentially blocked by the gravity valve block. The diameter of the flow channel holes 301 is distributed clockwise from the 6 o'clock position as "small-medium-large-small-large-medium". At this time, the wellhead mud pressure change cycle detected on the surface is "small-medium-large-small-large-medium". When the rotation stops, the last cycle of pressure change is "small-medium-large", thus obtaining the current drill string rotation angle as 180° clockwise. Passive angle measurement is achieved through the periodic fluctuation of mud pressure. When the drilling measurement equipment detects that the bottom hole temperature is too high and communication with the surface is required, the communication unit 14 receives the drilling measurement information and sends it to the control unit 13. The control unit 13 controls the heating drive unit 12 to heat the SMA springs 8 corresponding to the two small holes. The SMA springs 8 contract when heated to the phase transition temperature, which causes the reset spring 6 to stretch. The plug 7 blocks the corresponding flow channel hole. Then, the control unit 13 controls the heating drive unit 12 to cancel the heating. The SMA springs 8 no longer generate contraction force, the reset spring 6 contracts, which causes the SMA springs 8 to stretch, and the plug 7 resets. The corresponding flow channel hole is no longer blocked. Then, in the same principle, the control unit 13 controls the two medium holes to be blocked and reset, and the two large holes to be blocked and reset. The surface detects that the wellhead mud pressure rises in a gradient manner, thus obtaining a signal that the bottom hole temperature is too high. Other signals are transmitted by generating regular amplitude changes in the periodic signal of passive angle measurement.

Claims

1. A passive angle-measuring composite mud pulse generator based on SMA drive, characterized in that: The SMA-driven passive angle measurement composite mud pulse generator includes a passive angle measurement assembly, a composite encoding assembly, and an autonomous control assembly. The passive angle measuring assembly includes an upper connector (1), a gravity valve block (2), an encoding flow channel (3), a junction channel (9), a mounting cylinder (10), a drive frame (11), a lower connector (16), a locking nut (17), a snap ring (18), and a locking nut (19). The encoding flow channel (3) is threadedly connected and fixed to the upper connector (1). The encoding flow channel (3) rotates with the drill string. The encoding flow channel (3) has regularly distributed flow channel holes (301) and grooves (302) of different sizes. The gravity valve block (2) is locked by the locking nut. The mother (19) is axially fixed on the coding flow channel (3). The gravity valve block (2) has an eccentric block (201) pointing in the direction of gravity. The eccentric block (201) is close to the coding flow channel (3). When the coding flow channel (3) rotates with the drill string, the gravity valve block (2) always points in the direction of gravity. The eccentric block (201) blocks different flow channel holes (301) in sequence, so that the pressure of the drilling mud forms a periodic fluctuation. The ground can calculate the angle of tool rotation by filtering and interpreting the pressure fluctuation of the drilling mud, thus realizing passive angle measurement. The composite coding assembly includes a fixing groove (4), a sealing plate (5), a return spring (6), a plug (7), and an SMA spring (8). The fixing groove (4) is fixed to the coding channel (3) by screws, and the sealing plate (5) is fixed to the fixing groove (4) by screws. The fixing groove (4) has a wire groove (401), and the wire is installed in the wire groove (401). The plug (7) has a pressure plate (701) and a hole (702). The return spring (6) is installed in the hole (702) and connects the sealing plate (5) and the plug (7). The SMA spring (8) is insulated and connected to the heating drive unit. (12) When the SMA spring (8) is heated to the phase change temperature, it will contract. The SMA spring (8) is installed between the fixed groove (4) and the pressure plate (701). In the reset state, the reset spring (6) returns to the compressed state, which drives the SMA spring (8) to stretch. In the trigger state, the heating drive unit (12) heats the SMA spring (8) to the phase change temperature. The SMA spring (8) contracts, the reset spring (6) is stretched, and the blocker (7) moves down to block the flow channel hole (301). The area of ​​the flow channel hole (301) is reduced by half, forming a pressure-holding effect, thereby performing composite coding on the basis of passive angle measurement. The autonomous control assembly includes a heating drive unit (12), a control unit (13), a communication unit (14), and a power supply unit (15). The control unit (13) can control the heating drive unit (12) to output different currents to heat the SMA spring (8), thereby controlling the blocker (7) to block or reset. The communication unit (14) is responsible for receiving other signals measured while drilling. The power supply unit (15) provides power. The composite coding assembly consists of 6 groups, which are evenly installed in the groove (302) of the coding channel (3). Each group of composite coding assembly acts on a channel hole (301). The control unit (13) controls the 6 groups of composite coding assemblies to block the channel holes (301) in a regular manner, and modulates the signal in the peak value and peak period of the drilling mud pressure, thereby generating a composite signal based on passive angle measurement.

2. The passive angle-measuring composite mud pulse generator based on SMA drive according to claim 1 is characterized in that: The upper connector (1) and the lower connector (16) are connected by threads. The confluence channel (9) and the coding channel (3) are connected by screws. Drilling mud flows out from each channel hole (301) and converges into the confluence channel (9). The confluence channel (9) has a protrusion (901) that is positioned and installed with the coding channel (3). The spline groove (902) on the confluence channel (9) is circumferentially fixed with the spline (1001) inside the mounting cylinder (10). The confluence channel (9) and the mounting cylinder (10) are axially fixed by a locking nut (17). The mounting cylinder (10) is connected to the drive frame (11) by screws. The heating drive unit (12) is installed in the mounting port (1101) of the drive frame (11). The control unit (13), the communication unit (14) and the power supply unit (15) are installed on the mounting cylinder (10) and fixed by a snap ring (18). All installations are sealed.

3. The passive angle-measuring composite mud pulse generator based on SMA drive according to claim 1 is characterized in that: The diameter of the flow channel hole (301) is distributed clockwise from the 6 o'clock position as "small-medium-large-small-large-medium". The gravity valve block (2) always points to the gravity direction and is located at the 6 o'clock position. When the coded flow channel (3) rotates one circle, the gravity valve block (2) blocks the flow channel hole (301) in turn, corresponding to the pressure change "small-medium-large-small-large-medium" in turn. This is one cycle. After multiple rotations, the tool face angle can be measured by the pressure change cycle and the pressure amplitude of the last cycle.

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