Mud pulser

Abstract

A mud pulser comprises an inlet assembly, a main valve assembly, a servo valve assembly, a motor assembly and a drill collar. The servo valve assembly comprises a servo valve, the servo valve comprises a servo valve blocking piece and a servo valve cavity used for containing the servo valve blocking piece, and the servo valve cavity is provided with a first valve port and a second valve port. The servo valve rod is connected with the servo valve blocking piece and can be driven to reciprocate, so that the servo valve blocking piece can alternately block the first valve port and the second valve port. Alternating clogging of the first and second valve ports triggers movement in the main valve assembly to limit or release the flow of mud to form a mud pulse.

Description

Technical Field

[0001] This invention relates to a mud pulser for use in drilling systems, used to generate pulses in drilling mud to transmit information from the wellbore to the surface. Background Technology

[0002] Oil and gas exploration and extraction utilize drilling systems to deliver and guide the drill bit to the producing formation. During drilling, data collected by sensors needs to be transmitted up the wellbore to the surface. This data is then decoded / translated into information about parameters such as temperature, pressure, wellbore inclination or dip angle, wellbore orientation or azimuth, and various geophysical parameters that are of significant value during drilling.

[0003] Mud pulse telemetry is one method of transmitting data from the wellbore to the surface. LWD (Log While Drilling) and MWD (Measurement While Drilling) data are encoded (i.e., converted) into amplitude-modulated mud pulses or frequency-modulated mud pulses and transmitted via a mud column within the drill string to a computer device at the surface. It is important to note that the pulses in the mud are actually pressure pulses detectable by pressure sensors installed at the surface. "Mud pulse" and "pressure pulse" are used interchangeably herein. One or more computing devices at the surface can then decode the modulated mud pulses to obtain information about the characteristics of the subsurface formation. A pulse generator (or mud pulser) is a device that generates modulated mud pulses. An example of such a pulse generator can be found in US Patent Application US 2021 / 0340864 A1.

[0004] Drilling deeper wells places higher demands on mud pulsers. Mud pulsers must be able to withstand high temperatures and pressures, and generate strong pulses, but ideally consume less power. Therefore, a new type of pulse generator is needed to efficiently and reliably generate pressure pulses and transmit them to pressure sensors at the surface via drilling fluid. Summary of the Invention

[0005] According to one embodiment of the present invention, a mud pulser includes an inlet assembly, a main valve assembly, a servo valve assembly, a motor assembly, and a drill collar. The inlet assembly allows mud to flow in. The main valve assembly includes a main valve, a main valve stem, and a main valve passage. The main valve includes a main valve plug, a main valve seat adapted to receive the main valve plug, and a main valve cavity for accommodating the main valve plug. The main valve stem is fixed to the main valve plug. The main valve passage is disposed within the main valve stem and connected to the inlet assembly. The servo valve assembly includes a servo valve, a servo valve stem, and a servo valve passage. The servo valve includes a servo valve plug and a servo valve cavity for accommodating the servo valve plug, the servo valve cavity having a first valve port and a second valve port. The servo valve stem is connected to the servo valve plug and configured to be driven to reciprocate, thereby allowing the servo valve plug to alternately plug the first valve port and the second valve port. The servo valve passage is connected to the servo valve cavity and the main valve assembly. The motor assembly includes a motor connected to the servo valve stem, the motor being capable of driving the servo valve stem to reciprocate. The drill collar houses the inlet assembly, main valve assembly, servo valve assembly, and motor assembly. Inside the drill collar, mud channels are formed around the main valve assembly, servo valve assembly, and motor assembly.

[0006] In one aspect of this embodiment, the main valve is configured to generate a pressure pulse by mud pressure toward the inlet assembly when the servo valve blockage member blocks the second valve port. This mud pressure can be generated by mud flowing from the servo valve chamber through the servo valve passage.

[0007] In one aspect of this embodiment, the main valve is configured to allow slurry to flow from the main valve assembly toward the servo valve assembly through the slurry channel when the servo valve blockage member blocks the second valve port.

[0008] In one aspect of this embodiment, the inlet assembly further includes a filter element through which a portion of the slurry can flow from the slurry channel into the main valve channel.

[0009] In one aspect of this embodiment, the main valve assembly further includes a piston fixed to the main valve stem and a piston chamber for receiving the piston, the piston chamber being connected to the servo valve chamber.

[0010] In one aspect of this embodiment, the main valve assembly further includes a spring housed within the piston chamber.

[0011] In one aspect of this embodiment, the piston is mounted on the main valve stem in a manner that allows it to provide thrust to the main valve stem. A spring is configured to provide thrust to the piston by compression from mud pressure in the direction of reciprocating movement of the main valve stem.

[0012] In one aspect of this embodiment, the mud pulser further includes a positioning ring fixed to the inner surface of the drill collar, the positioning ring being connected to a servo valve assembly or a motor assembly and having an opening therethrough through which a mud channel can pass. Attached Figure Description

[0013] The teachings of the present invention can be readily understood by referring to the accompanying drawings and the detailed description below.

[0014] Figure 1 A cross-sectional view of a mud pulser according to an exemplary embodiment is shown.

[0015] Figure 2 It shows that other drill collars are connected at both ends. Figure 1 The diagram shows a cross-sectional view of the mud pulser.

[0016] Figure 3 Showing Figure 1 A three-dimensional view of the inlet assembly of the mud pulser shown.

[0017] Figure 4 Showing Figure 3 The cross-sectional view of the inlet component is shown.

[0018] Figure 5 Showing Figure 1 A perspective view of the main valve assembly of the mud pulser shown.

[0019] Figure 6A Showing Figure 5 The cross-sectional view of the main valve assembly is shown.

[0020] Figure 6B A detailed view of the main valve blockage component is shown.

[0021] Figure 7 Showing Figure 1 A perspective view of the servo valve assembly of the mud pulser shown.

[0022] Figure 8 Showing Figure 7 The diagram shows a cross-sectional view of the servo valve assembly.

[0023] Figure 9 Showing Figure 1 The diagram shows a partial cross-sectional view of the mud pulser, in which the servo valve of the servo valve assembly is in the closed position and the main valve of the main valve assembly is in the open position.

[0024] Figure 10 Showing Figure 1 The diagram shows a partial cross-sectional view of the mud pulser, with the servo valve and main valve both in the open position.

[0025] Figure 11 Showing Figure 1 The diagram shows a partial cross-sectional view of the mud pulser, with the servo valve in the open position and the main valve in the closed position.

[0026] Figure 12 Showing Figure 1 The diagram shows a partial cross-sectional view of the mud pulser, with the servo valve and main valve both in the closed position.

[0027] Reference numerals: 10 – Mud pulser; 100 – Mud channel; 110 – Inlet assembly; 111 – Filter element; 112 – Inlet channel; 113 – Salvage spear; 120 – Main valve assembly; 121 – Main valve; 122 – Main valve stem; 123 – Main valve channel; 124 – Main valve plug; 1241 – Bypass port; 125 – Main valve seat; 126 – Main valve chamber; 127 – Piston; 128 – Piston chamber; 129 – Spring; 130 – Servo valve assembly; 131 – Servo valve; 132 – Servo valve stem; 133 – Servo valve channel; 134 – Servo valve plug; 135 – Servo valve chamber; 136 – First valve port; 137 – Second valve port; 138 – Outlet port; 140 – Motor assembly; 141 – Motor; 150 – Drill collar; 160 – Positioning ring. Detailed Implementation

[0028] Figure 1 A cross-sectional view of a mud pulser 10 according to an exemplary embodiment is shown. The mud pulser 10 includes an inlet assembly 110, a main valve assembly 120, a servo valve assembly 130, and a motor assembly 140, which are connected in series and arranged within a drill collar 150. The drill collar 150 is annular and has a proximal end that is closer to the ground during operation and a distal end that is farther from the ground during operation.

[0029] The motor assembly 140 includes a motor 141. A mud passage 100 is formed within the drill collar 150 around the main valve assembly 120, the servo valve assembly 130, and the motor assembly 140. The drill collar 150 can be connected to other drill collars as part of a drill string. Figure 1 In this case, the mud pulser 10 was not connected to any other drill collar. Meanwhile... Figure 2 In this system, the mud pulser 10 is connected to one drill collar at its distal end and to another drill collar at its proximal end. The size and material of the drill collars 150 are adapted to specific drilling operations, such as depth and mud flow rate.

[0030] In this exemplary embodiment, the mud pulser 10 also includes a positioning ring 160. The positioning ring 160 is fixed to the inner surface of the housing 150 and connected to the motor assembly 140. The positioning ring 160 has an opening 161 that allows the mud channel 100 to pass through. A positioning ring with a different diameter than the diameter of the positioning ring 160 can adapt the servo valve assembly 130 or the motor assembly 140 to a drill collar with a different diameter than the diameter of the drill collar 150.

[0031] Figure 3 and Figure 4Perspective and cross-sectional views of the inlet assembly 110 of the mud pulser 10 are shown. The inlet assembly 110 includes a filter 111, an inlet channel 112, and a retrieval spear 113. The filter 111 prevents debris from entering the inlet channel 112, which directs the mud flow to the main valve assembly 120. The retrieval spear 113 is a component used for mounting and removing the pulse generator from the drill collar 150. When the pulse generator is assembled and in operation, the mud channel 100 is isolated from the inlet channel 112. The mud channel 100 leads into the drill collar and receives most of the mud flow.

[0032] Figure 5 and Figure 6A A perspective view and a cross-sectional view of the main valve assembly 120 of the mud pulser 10 are shown. The main valve assembly 120 includes a main valve 121 and a main valve stem 122 that runs through the main valve assembly. The hollow center of the main valve stem 122 serves as a main valve passage 123 for mud flow.

[0033] The main valve 121 also includes a main valve plug 124 that is sleeved on the main valve stem 122 and arranged in the main valve chamber 126. Figure 6B A detailed view of the main valve plug 124 is shown. It should be noted that a plurality of grooves 1241 are provided on the proximal surface of the main valve plug 124. When the main valve plug 124 engages with the main valve seat 125, these grooves form bypass ports, allowing a small portion of the mud flow to enter the main valve chamber 126 and continue flowing into the mud passage 100. Therefore, when the main valve 121 is closed, the main valve plug 124 restricts the mud flow, but does not completely block it.

[0034] When the main valve plug 124 disengages from the main valve seat 125, the main valve opens, allowing the mud flow to pass through the main valve 121 without restriction (e.g., with minimal restriction within design limits). Therefore, movement of the main valve plug 124 alternately restricts or releases the mud flow, thereby creating pressure pulses in the mud flow.

[0035] It should be noted that the main valve passage 123 is located within the main valve stem 122 and connected to the inlet assembly 110, allowing a small diversion of mud to enter the passage 123. However, the majority of the mud flow passes through the mud passage 100 in the inlet assembly, fills the main valve chamber 126, and continues to flow downstream into the drill collar. In this case, the main valve chamber 126 can be considered as part of the mud passage 100.

[0036] The main valve plug 124 is fixed to the main valve stem 122, which abuts against the piston 127. The piston 127, in turn, contacts a spring 129 located within the piston chamber 128. The operation of the main valve 121 will be described in other parts of this document. In short, the piston 127 is configured to move back and forth, causing the main valve plug 124 to engage or disengage from the valve seat 125, thereby closing or opening the main valve 121. The stroke length of the main valve plug can vary depending on the design, ranging from 0.25” to 0.75”, for example, 0.50”.

[0037] In this paper, the state of the main valve 121 when the main valve plug 124 is separated from the main valve seat 125 is defined as the open position, and the state of the main valve 121 when the main valve plug 124 is engaged with the main valve seat 125 is defined as the closed position.

[0038] Figure 7 and Figure 8 A perspective view and a cross-sectional view of the servo valve assembly 130 of the mud pulser 10 are shown. The servo valve assembly 130 includes a servo valve 131, a servo valve stem 132, and multiple servo valve channels 133. The servo valve 131 includes a servo valve plug 134 and a servo valve chamber 135. The servo valve chamber 135 communicates with the piston chamber 128 through the servo valve channels 133. The servo valve chamber 135 also accommodates the servo valve plug 134. The servo valve chamber 135 has a first valve port 136 at its proximal end and a second valve port 137 at its distal end. The servo valve chamber 135 is also connected to the mud channel 100 through the second valve port 137 and multiple outlet holes 138 on the outer wall of the servo valve assembly 130. The servo valve stem 132 is connected to the servo valve plug 134 at its proximal end and to the motor 141 at its distal end.

[0039] In this embodiment, the servo valve blocking element 134 is a lift valve with two tips. The proximal end of the lift valve is designed to engage with and close the first valve port 136. The distal end of the lift valve is designed to engage with and close the second valve port 137. When the servo valve blocking element 134 blocks the first valve port 136, the state of the servo valve 131 is defined as the closed position; and when the servo valve blocking element 134 blocks the second valve port 137, the state of the servo valve 131 is defined as the open position.

[0040] The operation of the mud pulser 10 with this configuration will now be described. During operation, most of the mud flow fills the mud passage 100 in the inlet assembly 110, fills the main valve chamber 126, and applies pressure to the main valve plug 124. On the other hand, a small portion of the mud flow in the drill collar enters the inlet assembly 110 through the filter 111, fills the inlet passage 112 and the main valve passage 123 in the main valve assembly 120, and reaches the servo valve chamber 135 when the first valve port 136 is open. When the second valve port 137 is blocked by the servo valve plug 134, the mud flow enters the piston chamber 128 through the servo valve passage 133. The mud flow thus applies pressure to the piston 127, which in turn applies reverse pressure to the main valve plug 124 to close the main valve 121.

[0041] Motor 141 drives servo valve stem 132 to cause servo valve plug 134 to reciprocate within the servo valve chamber, alternately plugging the first and second valve ports. Pluging the first valve port reduces the reverse pressure and opens the main valve 121, while plugging the second valve port increases the reverse pressure and closes the main valve 121. The change in the relative magnitude of the positive and reverse pressures acting on the main valve plug 124 causes the main valve plug 124 to reciprocate, thereby restricting and releasing the mud flow to form pulses.

[0042] Figure 9 This illustration shows the servo valve 131 in the closed position and the main valve 121 in the open position. When the servo valve 131 is in the closed position (i.e., the servo valve plug 134 is blocking the first valve port 136), the slurry flowing from the inlet assembly 110 through the main valve passage 123 cannot flow further past the servo valve plug 134. Furthermore, since the main valve 121 is in the open position (i.e., the main valve plug 124 is separated from the main valve seat 125), the slurry flows through the main valve chamber 126 in the slurry passage 100, passing through the main valve assembly 120 and the servo valve assembly 130.

[0043] Figure 10 This shows the situation where servo valve 131 is in the open position and main valve 121 is also in the open position. Because servo valve 131 is in the open position (i.e., the servo valve plug 134 blocks the second valve port 137), slurry flows through servo valve plug 134 into servo valve chamber 135. However, because the second valve port 137 is blocked by servo valve plug 134, the slurry cannot leave servo valve chamber 135. Therefore, the slurry in servo valve chamber 135 flows into piston chamber 128 through servo valve passage 133. Simultaneously, main valve 121 is in the open position, and the slurry... Figure 9 The same manner is shown, with the slurry flowing through the main valve chamber 126 in the mud channel 100 to the main valve assembly 120 and the servo valve assembly 130.

[0044] Figure 11 This shows a situation where servo valve 131 is in the open position and main valve 121 is in the closed position. This situation can occur when... Figure 10 Following the operating mode shown. Specifically, when the mud pressure flowing from the servo valve chamber 135 into the piston chamber 128 increases, the piston 127 moves toward the inlet assembly 110. When the sum of the pressure of the compression spring 129 and the mud pressure flowing from the servo valve chamber 135 into the piston chamber 128 reaches a certain threshold pressure, the main valve plug 124 engages with the main valve seat 125, thereby placing the main valve 121 in the closed position. When the main valve 121 transitions from the open position to the closed position, the mud flowing into the mud passage 100 is restricted as it enters the main valve chamber 126. This restriction on the mud flow generates pressure surges in the mud flow, thus forming mud pulses.

[0045] Figure 12 The diagram shows the situation where both servo valve 131 and main valve 121 are in the closed position. When servo valve 131 is in the closed position, since the first valve port 136 is closed when servo valve 131 is in the closed position, the slurry in servo valve passage 133 and servo valve chamber 135 flows through slurry passage 100 via second valve port 137 and outlet hole 138 on the outer wall of servo valve assembly 130. This releases the pressure in piston chamber 128, causing the sum of the pressure of compression spring 129 and the slurry pressure flowing from servo valve chamber 135 into piston chamber 128 to fall below the threshold pressure. Consequently, under the action of slurry pressure flowing from inlet assembly 110 to main valve assembly 120, main valve plug 124 separates from main valve seat 125, thereby placing main valve 121 in the open position.

[0046] Figure 1-12 One embodiment of the invention is shown. Modifications can be made to this embodiment without departing from the basic design and working principle.

[0047] In some other embodiments, the main valve can be closed without using the spring 129, solely by the force generated by the mud flow from the servo valve chamber.

[0048] In other embodiments, the same components can be scaled up or down to accommodate different mud flow rates, mud flow pressures, etc. For example, the inner diameter of the drill collar used to house the mud pulser can range from 2.531” to 5.859”, for example, 3.469”. The inner diameter of the drill collar further defines the outer diameter of the main valve assembly. The valve port size of the main valve seat is between 1.115” and 2.375”, for example, 1.750”. The size of the first valve port in the servo valve chamber is between 0.125” and 0.375”, for example, 0.250”. The size of the second valve port in the servo valve chamber is between 0.438” and 0.750”, for example, 0.594”. The stroke length of the servo valve plug is between 0.250” and 0.750”, for example, 0.500”.

[0049] The descriptions of features or aspects in each example should be considered applicable to similar features or aspects in other examples as well. Suitable effects may also be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the invention is not limited by the specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included herein.

Claims

1. A mud pulser comprising: an inlet assembly adapted to receive a flow of mud; a main valve assembly including a main valve, a main valve stem, and a main valve passage, wherein the main valve includes a main valve plug, a main valve seat adapted to receive the main valve plug, and a main valve cavity for housing the main valve plug, wherein the main valve plug is fixed to the main valve stem, and wherein the main valve passage is disposed within the main valve stem and is connected to the inlet assembly; a servo valve assembly including a servo valve, a servo valve stem, and a servo valve passage, wherein the servo valve includes a servo valve plug and a servo valve cavity for housing the servo valve plug, the servo valve cavity having a first valve port and a second valve port, wherein the servo valve stem is connected to the servo valve plug and is configured to be driven for reciprocal movement so that the servo valve plug can alternately block the first valve port and the second valve port, and wherein the servo valve passage is connected to the servo valve cavity and the main valve assembly; a motor assembly including a motor connected to the servo valve stem, the motor being capable of driving the servo valve stem for reciprocal movement; and a drill collar capable of housing the inlet assembly, the main valve assembly, the servo valve assembly, and the motor assembly, and forming a mud passage for receiving a flow of mud therein, the mud passage surrounding the main valve assembly, the servo valve assembly, and the motor assembly.

2. The mud pulser of claim 1, wherein, The inlet assembly further includes a filter.

3. The mud pulser of claim 1, wherein, The main valve assembly further includes a piston fixed to the main valve stem, and a piston cavity for housing the piston, the piston cavity being connected to the servo valve cavity.

4. The mud pulser of claim 1, wherein, During operation, a pressure change in the flow of mud is created by exerting a force on the piston toward the inlet assembly when the servo valve plug blocks the first valve port.

5. The mud pulser of claim 3, wherein, The main valve assembly further includes a spring housed within the piston cavity, wherein the spring is in contact with the piston.

6. The mud pulser of claim 5, wherein, The piston is mounted on the main valve stem in a manner that the first force is exerted on the main valve stem, and the spring is disposed to be compressed by the mud pressure in a direction of reciprocal movement of the main valve stem so as to exert a second force on the piston.

7. The mud pulser of claim 1, wherein, A retaining ring is further included, the retaining ring being fixed to an inner surface of the drill collar and connected to the servo valve assembly or the motor assembly, the retaining ring having an opening through which the mud passage can extend.

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