A small-displacement mud pulse MWD screw motor damper

Abstract

This utility model discloses a small-displacement mud pulse MWD screw motor damper, including a tubular pulse suppressor. From the instrument connection end to the MWD screw motor connection end, the tubular pulse suppressor is sequentially equipped with a nozzle, a spacer ring, and a negative pressure noise suppressor. The small-displacement mud pulse MWD screw motor damper utilizes the flow characteristics of fluid in different pipe diameter channels to generate a local negative pressure area, suppressing eddies and turbulence in the mud flow, disrupting vortex formation, thereby reducing pressure pulsation and noise. During mud transport, the mud flows into the damper from the upper connecting pipe, passes through the nozzle for dispersion, the spacer ring for velocity and pressure adjustment, and then enters the mixing chamber, throat, and diffusion chamber of the negative pressure noise suppressor for further processing, finally flowing smoothly to the screw motor below. Through the synergistic effect of these noise-reducing components, pipeline vibration and mud pressure pulsation caused by the screw motor are effectively reduced, ensuring the stable operation of the mud transport system.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic system technology, specifically relating to a small displacement mud pulse MWD screw motor wave suppressor. Background Technology

[0002] In the exploration and development of oil and gas, Measurement While Drilling (MWD) technology plays a crucial role, and the stable performance of the MWD screw motor, as the core power component of this technology system, is paramount. Within the management system, on the one hand, the screw motor generates strong mechanical vibrations during operation. The screw motor's working principle involves driving a rotor to rotate using high-pressure drilling mud; this rotational motion causes vibrations in itself and connected components. The direct connection between the screw motor and the instrument means that this vibration is transmitted indiscriminately to the instrument, affecting not only the measurement accuracy but also, over time, potentially causing loosening and damage to internal components, significantly shortening the instrument's lifespan. On the other hand, due to the direct connection between the screw motor and the instrument, the eddy currents in the upstream pipeline have a significant impact on the fluid in the downstream pipeline. When the drilling mud flows in the pipeline, the operation of the screw motor creates complex eddy currents in the surrounding water flow. These eddies cause instability in the drilling mud pressure, i.e., pressure pulsation. Pressure pulsation not only reduces the efficiency of drilling mud delivery and increases energy loss but also causes additional impacts on the pipeline system, accelerating pipeline wear and aging. In some long-distance, large-diameter mud transport pipelines, pressure pulsation may even cause resonance in the pipeline, seriously threatening the safe operation of the pipeline system.

[0003] Currently, while some solutions exist for the problems faced by MWD screw motors, most suffer from complex structures, high costs, and difficulties in practical application. Therefore, developing a device that effectively reduces pipeline vibration and mud pressure pulsation in MWD screw motors, with a simple structure and reliable performance, is of paramount practical significance for improving the efficiency and quality of oil drilling operations and reducing costs and risks. Utility Model Content

[0004] This invention provides a small-displacement mud pulse MWD screw motor damper, which can solve the problems existing in the prior art.

[0005] To solve the above problems, the technical solution provided by this utility model is as follows:

[0006] This utility model embodiment provides a small displacement mud pulse MWD screw motor damper, including a tubular pulse pressure device (1), one end of which is an instrument connection end and the other end is an MWD screw motor connection end; a nozzle (2), a spacer ring (3) and a negative pressure noise suppressor (4) are sequentially arranged between the instrument connection end and the MWD screw motor connection end of the tubular pulse pressure device (1).

[0007] The nozzle (2) is made of wear-resistant hard material to resist the wear caused by high-speed mud scouring; the cross-sectional area of ​​the flow channel of the spacer ring (3) is larger than that of the flow channel of the nozzle (2); the spacer ring (3) is arranged at intervals along the mud flow direction inside the tubular pressure pulsator (1). When the mud dispersed by the nozzle (2) flows through the spacer ring (3), the cross-sectional area of ​​the flow channel changes. According to the principle of fluid mechanics, the flow velocity and pressure distribution of the mud are adjusted, thereby optimizing the mud flow state, further stabilizing the flow velocity, and reducing the pressure pulsation amplitude.

[0008] The negative pressure noise suppressor (4) includes a mixing chamber (4-1), a throat (4-2), and a diffusion chamber (4-3). The opening of the mixing chamber (4-1) is a contraction structure with a gradually decreasing diameter. It is located on the side near the mud outlet of the spacer ring (3). The mixing chamber (4-1) ensures that the mud passing through the spacer ring (3) is fully mixed, disrupting any potential local unstable flow state within the mud. The opening of the throat (4-2) is a circular structure, used to connect after the mixing chamber (4-1). When the mud enters the throat (4-2) from the mixing chamber (4-1), the flow velocity increases instantaneously. According to Bernoulli's principle, the mud pressure decreases at this time, which helps to further suppress eddies and turbulence in the mud. The opening of the diffusion chamber (4-3) is a scaling structure with a gradually increasing diameter, used to connect after the throat (4-2). When the mud flow velocity in the diffusion chamber (4-3) gradually decreases, the pressure gradually recovers, but at this time the mud flow is more stable, and pressure pulsation is effectively suppressed.

[0009] In an optional embodiment of this utility model, the nozzle (2) has a plurality of grooves (2-3) on its side, and the tubular pulse injector has a plurality of protrusions corresponding to the plurality of grooves (2-3). The plurality of grooves (2-3) and the plurality of protrusions are connected by an interlocking method.

[0010] In one optional embodiment of this utility model, an O-ring is also fitted between each groove (2-3) and its corresponding protrusion.

[0011] In an optional embodiment of this utility model, the nozzle (2) has a notch (2-4) on the side facing the spacer ring (3), and one end of the spacer ring (3) is fixed against the notch (2-4).

[0012] Compared with existing technologies, this utility model provides a small-displacement mud pulse MWD screw motor silencer with the following effects: This small-displacement mud pulse MWD screw motor silencer utilizes the flow characteristics of fluid in different pipe diameter channels to generate local negative pressure areas, suppressing eddies and turbulence in the mud flow, disrupting vortex formation, thereby reducing pressure pulsation and noise. During mud transport, the mud flows into the silencer from the upper connecting pipe, sequentially passing through the nozzles for dispersion, the spacer rings for velocity and pressure adjustment, and then entering the mixing chamber, throat, and diffusion chamber of the negative pressure noise suppressor for further processing, finally flowing smoothly to the screw motor below. Through the synergistic effect of these silencer components, pipeline vibration and mud pressure pulsation caused by the screw motor are effectively reduced, ensuring the stable operation of the mud transport system. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a cross-sectional schematic diagram of a small-displacement mud pulse MWD screw motor damper provided in an embodiment of this application.

[0015] Figure 2 A schematic diagram of the nozzle cross-section of a small-displacement mud pulse MWD screw motor damper provided in an embodiment of this application.

[0016] Figure 3 A schematic diagram of the spacer ring cross-section of a small displacement mud pulse MWD screw motor silencer provided in an embodiment of this application.

[0017] Figure 4 A schematic diagram of the negative pressure noise suppressor of a small displacement mud pulse MWD screw motor wave suppressor provided in this application embodiment.

[0018] Figure 5 A schematic diagram of the negative pressure ring cross-section of a small displacement mud pulse MWD screw motor damper provided in an embodiment of this application.

[0019] Figure 6 This is a schematic diagram of the cross-sectional dimensions of a nozzle provided in an embodiment of this application.

[0020] Figure 7 This is a schematic diagram of the cross-sectional dimensions of a spacer ring provided in an embodiment of this application.

[0021] Figure 8This is a schematic diagram of the cross-sectional dimensions of a negative pressure noise suppressor provided in an embodiment of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The terms "upper," "lower," "front," "rear," "left," and "right," etc., used when describing the installation position or direction of the structure or components in this embodiment are based on the orientation shown in the accompanying drawings. They are merely for convenience of description, used to distinguish the relative positions of various components or directions, and do not represent the orientation of the device or functional component in this embodiment during use.

[0023] In response to the problem that the direct connection between the screw motor and the instrument in the existing technology results in strong mechanical vibration and water flow turbulence in the front pipeline affects the fluid in the rear pipeline, this utility model provides a small displacement mud pulse MWD screw motor damper, which aims to effectively attenuate pressure pulsation and reduce the impact of vibration.

[0024] like Figures 1-4 As shown, a small-displacement mud pulse MWD screw motor damper includes a tubular pulse injector 1, with one end serving as an instrument connection end and the other as an MWD screw motor connection end. From the instrument connection end to the MWD screw motor connection end, a nozzle 2, a spacer ring 3, and a negative pressure noise suppressor 4 are sequentially arranged on the tubular pulse injector 1. The instrument connection end has a connection interface adapted to the instrument, which is tightly connected to the instrument pipeline via threads or other sealing connections to prevent mud leakage. The MWD screw motor connection end is designed with a connection interface to the screw motor to ensure a stable connection with the screw motor.

[0025] Nozzle 2 is made of wear-resistant hard material to resist the wear caused by high-speed mud erosion. The cross-sectional area of ​​the flow channel of the spacer ring 3 is larger than that of the flow channel of nozzle 2. The spacer rings 3 are arranged at intervals along the mud flow direction inside the tubular pressure vent 1. When the mud dispersed by nozzle 2 flows through the spacer rings 3, the cross-sectional area of ​​the flow channel changes. According to the principles of fluid mechanics, the flow velocity and pressure distribution of the mud are adjusted, thereby optimizing the mud flow state, further stabilizing the flow velocity, and reducing the pressure pulsation amplitude.

[0026] The negative pressure noise suppressor 4 includes a mixing chamber 4-1, a throat 4-2, and a diffusion chamber 4-3. The mixing chamber 4-1 has a converging opening with a gradually decreasing diameter, located near the mud outlet of the spacer ring 3. The mixing chamber 4-1 ensures thorough mixing of the mud passing through the spacer ring 3, disrupting any potential localized unstable flow within the mud. The throat 4-2 has a circular opening and connects to the mixing chamber 4-1. When the mud enters the throat from the mixing chamber 4-1, the flow velocity increases instantaneously. According to Bernoulli's principle, this reduces the mud pressure, further suppressing eddies and turbulence in the mud. The diffusion chamber 4-3 has a tapering opening with a gradually increasing diameter, connecting to the throat 4-2. As the mud flow velocity gradually decreases within the diffusion chamber 4-3, the negative pressure ring 5 accelerates the formation of a localized strong negative pressure zone through the annular gap flow channel. This localized negative pressure causes some mud to flow back in reverse, reducing the pulsation amplitude. The pressure gradually recovers, but the mud flow is now more stable, and pressure pulsations are effectively suppressed. Figure 4 and Figure 5 , Figure 4 The position indicated by the dashed line is the negative pressure ring 5.

[0027] Figure 2 Combination Figure 1 The nozzle 2 is provided with a sloping flow channel 2-1 and a circular flow channel 2-2. Multiple grooves 2-3 are provided on the side of the nozzle 2, and a tubular pressure device is provided with multiple protrusions corresponding to these grooves 2-3. The grooves 2-3 and the protrusions are connected by an interlocking mechanism. An O-ring seal is also fitted between each groove 2-3 and its corresponding protrusion. A notch 2-4 is provided on the side of the nozzle 2 facing the spacer ring 3, and one end of the spacer ring 3 is held in place by the notch 2-4.

[0028] Structurally, this invention innovatively employs a special mechanical isolation structure (vibration damping structure) to isolate the screw motor from the instrument, preventing the strong mechanical vibrations generated by the screw motor from being directly transmitted to the instrument. This isolation structure (vibration damping structure) not only effectively buffers vibrations, but its compact design also avoids occupying excessive space, allowing for flexible installation of the entire tubular pulse compressor within limited tubing space. These isolation structures (vibration damping structures) effectively absorb and attenuate vibration energy while transmitting power, significantly reducing the vibration experienced by the instrument.

[0029] Figure 6 , Figure 7 and Figure 8 The dimensions marked in the figure are preferred dimensions designed and used by the inventor, and the unit of measurement is mm. No limitation is made in other embodiments.

[0030] Figure 6 Combination Figure 2The nozzle is made of wear-resistant, hard material to resist the abrasion caused by high-speed slurry erosion. The nozzle has a specific orifice shape; when slurry flows into the damper from the upper connecting pipe, it first passes through the nozzle. The nozzle outlet diameter is generally available in 7, 8, 9, and 10 mm, with 10 mm being preferred. For a given pump flow rate, a smaller nozzle outlet diameter results in a higher flow velocity and, within a certain range, a higher negative pressure. However, a nozzle outlet diameter that is too small is prone to clogging by debris. The taper β of the nozzle's ramp flow channel is generally between 8 and 15º; β takes a smaller value for higher pump pressures and a larger value for lower pressures. The ratio of the nozzle outlet diameter to the nozzle inlet diameter D is generally not less than 1 / 4. When β = 13º-15º, the nozzle length L0 = 2.2(D-d0) + d0, preferably 74 mm.

[0031] Figure 7 Combination Figure 3 Spacer rings are spaced apart along the direction of mud flow within the tubular pressure injector. They are typically made of metal, with an inner diameter smaller than that of the tubular pressure injector, forming an annular gap between the spacer rings and the injector. When the mud dispersed by the nozzle flows through the spacer rings, the cross-sectional area of ​​the flow channel changes. According to fluid mechanics principles, the mud velocity and pressure distribution are adjusted, thereby optimizing the mud flow state, further stabilizing the flow velocity, and reducing the amplitude of pressure pulsations.

[0032] Figure 8 Combination Figure 4 The negative pressure noise suppressor includes a mixing chamber, a throat, and a diffusion chamber. The mixing chamber typically has a convergence angle δ = 20-30º, an inlet diameter d1 = (1.5-2.0)d2, and a length L1 = 4.75(d1-d2), with the preferred length L1 being 21 mm. Located near the mud outlet of the spacer ring, its internal space is designed to ensure thorough mixing of the mud passing through the spacer ring, disrupting any potential localized unstable flow patterns within the mud.

[0033] The throat is generally selected with a diameter of d2 = (1.5-3.0)d0, preferably 20mm. The throat length L1 is selected empirically, with L2 = (1.2-1.7)d2. Connected after the mixing chamber, its diameter is relatively small. When the mud enters the throat from the mixing chamber, the flow velocity increases instantaneously. According to Bernoulli's principle, the mud pressure decreases at this time, which helps to further suppress eddies and turbulence in the mud.

[0034] The diffuser chamber is typically selected with a γ = 6-12º. The diameter d3 of the diffuser tube is empirically chosen as d3 = (2.5-4.0)d2, and the length L3 is calculated using the empirical formula L3 = 7.1(d3-d2). After connecting to the throat, the tube diameter gradually increases, the slurry velocity within the diffuser chamber gradually decreases, and the pressure gradually recovers. However, at this point, the slurry flow is more stable, and pressure pulsations are effectively suppressed.

[0035] The distance S between the nozzle and the mixing chamber: The optimal value is determined based on surface tests. Commonly used values ​​are between -5 and 20 mm. The lower cross-sectional area should be larger than the diffuser outlet cross-sectional area, and the suction hole must compensate for the negative pressure suction with minimal flow resistance. The ratio of the drain hole cross-sectional area to the suction hole cross-sectional area to the diffuser outlet cross-sectional area is 12:8:6.

[0036] This small-displacement mud pulse MWD screw motor silencer utilizes the flow characteristics of fluid in pipes of different diameters to generate localized negative pressure zones, suppressing eddies and turbulence in the mud flow, disrupting vortex formation, thereby reducing pressure pulsations and lowering noise generated by mud flow. During mud transport, the mud flows into the silencer from the upper connecting pipe, passes through nozzles for dispersion, and undergoes velocity and pressure adjustments via spacer rings. It then enters the mixing chamber, throat, and diffusion chamber of the negative pressure noise suppressor for further processing, finally flowing smoothly to the screw motor below. Through the synergistic effect of these noise-reducing components, pipeline vibration and mud pressure pulsations are effectively reduced, ensuring the stable operation of the mud transport system.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A small-displacement mud pulse MWD screw motor damper, characterized in that, The device includes a tubular pulse depressor (1), one end of which is an instrument connection end and the other end is an MWD screw motor connection end; a nozzle (2), a spacer ring (3) and a negative pressure noise suppressor (4) are sequentially arranged between the instrument connection end and the MWD screw motor connection end of the tubular pulse depressor (1). The nozzle (2) is made of wear-resistant hard material to resist the wear caused by high-speed mud scouring; the cross-sectional area of ​​the flow channel of the spacer ring (3) is larger than that of the flow channel of the nozzle (2); the spacer ring (3) is arranged at intervals along the mud flow direction inside the tubular pressure pulsator (1). When the mud dispersed by the nozzle (2) flows through the spacer ring (3), the cross-sectional area of ​​the flow channel changes. According to the principle of fluid mechanics, the flow velocity and pressure distribution of the mud are adjusted, thereby optimizing the mud flow state, further stabilizing the flow velocity, and reducing the pressure pulsation amplitude. The negative pressure noise suppressor (4) includes a mixing chamber (4-1), a throat (4-2), and a diffusion chamber (4-3). The opening of the mixing chamber (4-1) is a contraction structure with a gradually decreasing diameter. It is located on the side near the mud outlet of the spacer ring (3). The mixing chamber (4-1) ensures that the mud passing through the spacer ring (3) is fully mixed, disrupting any potential local unstable flow state within the mud. The opening of the throat (4-2) is a circular structure, used to connect after the mixing chamber (4-1). When the mud enters the throat (4-2) from the mixing chamber (4-1), the flow velocity increases instantaneously. According to Bernoulli's principle, the mud pressure decreases at this time, which helps to further suppress eddies and turbulence in the mud. The opening of the diffusion chamber (4-3) is a scaling structure with a gradually increasing diameter, used to connect after the throat (4-2). When the mud flow velocity in the diffusion chamber (4-3) gradually decreases, the pressure gradually recovers, but at this time the mud flow is more stable, and pressure pulsation is effectively suppressed.

2. The small-displacement mud pulse MWD screw motor damper according to claim 1, characterized in that, The nozzle (2) has multiple grooves (2-3) on its side, and the tubular pulse injector has multiple protrusions corresponding to the multiple grooves (2-3). The multiple grooves (2-3) and the multiple protrusions are connected by an interlocking method.

3. The small-displacement mud pulse MWD screw motor damper according to claim 2, characterized in that, Each groove (2-3) is also fitted with an O-ring between its corresponding protrusion and the groove (2-3).

4. The small-displacement mud pulse MWD screw motor damper according to claim 2, characterized in that, The nozzle (2) has a notch (2-4) on the side facing the spacer ring (3), and one end of the spacer ring (3) is fixed against the notch (2-4).

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