Patent Application
20220003045
In the process of drilling oil and gas wells, downhole drilling motors may be connected to a drill string to rotate and steer a drill bit. Conventional drilling motors typically provide rotation with a power section, which may be a positive displacement motor driven by circulation of drilling fluid or drilling mud.
As wellbores are drilled faster, higher flow rates of drilling fluid are required to clear drill cuttings from the wellbore. Each drilling motor is designed to operate with a maximum flow rate of the drilling fluid. For example, a conventional drilling motor having an outer diameter of 6.75 inches may be designed for a maximum flow rate of about 600 gallons per minute (GPM). Exceeding the maximum flow rate for a drilling motor may cause premature failure of the bearing section due to erosion.
Existing tools can divert a portion or all of the drilling fluid above the drilling motor in order to reduce the flow rate of the drilling fluid before it reaches the drilling motor. If a tool is used to bypass all drilling fluid to the annulus, the drilling fluid can be changed to a different media, such as a LCM drilling fluid or even a fracking fluid. Some bypass diverter tools include passive valves, which are activated by an independent mechanism. For example, a ball, dart, or RFID device inserted into the drilling fluid at the surface engages a receptacle when it reaches the diverter tool, and this interaction opens the valve to begin diverting drilling fluid into the well annulus above the drilling motor. However, these passive valve tools involve a delay of 10 minutes to 15 minutes from the time the action is taken (e.g., the ball or dart is dropped at the surface) to the time the valve is opened. This delay increases the cost of drilling a wellbore.
Other bypass diverter tools include active valves, which are activated automatically in response to a downhole parameter. For example, a change in flow rate, pressure, density, or rotational rate to a predetermined threshold value automatically opens a valve to divert a portion of the drilling fluid into the wellbore annulus above the drilling motor. However, these active valve tools are sometimes unintentionally activated by downhole parameter changes independent from surface activation, such as vibration, bit plugging, or motor stalling. There is a need for an active valve tool that diverts a portion of a fluid flowing through a drill string into a wellbore annulus that is not unintentionally activated.
A flow rate control system includes a valve assembly slidingly disposed within a housing. The valve assembly slides between a closed position, a partially open position, and a fully open position. A spring applies a spring force to bias the valve assembly toward the closed position. The valve assembly is flow rate controlled in the closed position and pressure controlled in the fully open position.
In one embodiment, the flow rate control system also includes a sleeve assembly fixed within the housing. The valve assembly is slidingly disposed within the sleeve assembly to slide between the closed position, the partially open position, and the fully open position.
In the closed position, a fluid flowing through the system applies a force on a first active valve area. Increases in the fluid flow rate apply increased forces on the first active valve area. When the increased force exceeds a threshold value that overcomes the spring force, the valve assembly begins to slide toward the partially open position. When the valve assembly reaches the partially open position, a portion of the fluid may begin to flow through a bypass fluid path that leads to an annular space surrounding the housing. In this way, the flow rate control system ensures that the flow rate of fluid flowing to a drilling motor positioned below (i.e., downstream) does not exceed a maximum flow rate value that the drilling motor is designed to tolerate. Instead, the excess fluid flow is diverted through the bypass fluid path into the annular space surrounding the housing. The valve assembly has a second active valve area, which becomes active in the partially open position and remains active in the fully open position. The second active valve area is biased downward by the pressure differential between an inner bore of the valve assembly and the annular space around the housing. In the partially open and fully open positions, the pressure in the system applies a downward force on the second active valve area. When the bypass fluid flow begins in the partially open position, the force applied to the second active valve area continues to move the valve assembly toward the fully open position and prevents the valve assembly from closing.
In one embodiment, the valve assembly includes valve bypass bores providing fluid communication across a valve collar. In the closed position, the pressure above the valve collar is equal to the pressure below the valve collar. For this reason, the valve assembly is flow rate controlled in the closed position. However, in the partially open and fully open positions, the valve bypass bores are in fluid communication with the annular space surrounding the housing such that the pressure below the valve collar is less than the pressure above the valve collar. For this reason, the valve assembly is a pressure controlled valve in the partially open and fully open positions.
Accordingly, if the fluid pumping temporarily stops or slows (e.g., the pump stops, the drill bit becomes plugged, or the motor stalls), the valve assembly will not change position (i.e., the valve assembly will not return to the closed position) until the pressure differential between the inside of the flow rate control system and the annular space surrounding the housing is reduced. Increasing the pressure in the annular space, decreasing the pressure in the drill string, or allowing the pressure to equalize through the bypass fluid path allows the spring, which is exerting a force on the valve assembly in an upward direction toward the closed position, to begin to close the valve. When this upward force exceeds the force exerted on the second active valve area in the downward direction, the valve assembly moves into the closed position again.
In one embodiment, the flow rate control system includes dampening chambers disposed between the valve assembly and the sleeve assembly. Dampening nozzles through a radial surface of the valve assembly allow fluid communication between an inner bore of the valve assembly and the dampening chambers to slow the sliding movement of the valve assembly relative to the sleeve assembly.
In one embodiment, the flow rate control system may include a complete bypass position in which the inner bore of the valve assembly is completely closed below the bypass fluid path. In the complete bypass position, all of the drilling fluid flowing through the system is diverted to the annulus and the flow of drilling fluid to the motor below is stopped. With the flow rate control system in the complete bypass position, the drilling fluid can be replaced by other types of fluids, such as LCM fluid, perforating fluid, or fracking fluid.
Flow rate control system 10 may include sleeve assembly 17 secured within housing inner bore 18 and valve assembly 19 slidingly disposed within sleeve assembly 17. Sleeve assembly 17 may include valve sleeve 20, valve stop 22, and spring sleeve 24. Upper ring 26 may be secured within housing inner bore 18 between an upper end of valve sleeve 20 and a lower end of upper sub 12. In this way, sleeve assembly 17 is secured within housing inner bore 18 between upper ring 26 and lower housing shoulder 28. Valve assembly 19 may include valve 30, orifice ring 32, and spring mandrel 34. Spring 36, lower spring ring 38, and upper spring ring 40 may each be disposed around spring mandrel 34 and within spring sleeve 24. A lower end of spring 36 may engage lower spring ring 38, and an upper end of spring 36 may engage upper spring ring 40. Housing 14 may include one or more housing bypass openings 41 extending radially from housing inner bore 18 to an outer surface of housing 14. Housing 14 may include any number of housing bypass openings 41. For example, housing 14 may include between 1 and 10 housing bypass openings 41. Valve sleeve 20 is aligned with the one or more housing bypass openings 41 within housing inner bore 18, and valve 30 is slidingly disposed within an inner bore of valve sleeve 20.
With reference to
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Valve stop 22 is disposed within housing inner bore 18 below valve sleeve 20. Valve stop 22 may be formed of a generally tubular ring. The inner bore of valve stop 22 may include recess 136 configured to house an O-ring or other seal mechanism for providing a fluid seal between spring mandrel 34 and valve stop 22. In one embodiment, an upper end of seal block 120 engages a lower end of valve stop 22 in the closed position. Ports 132 and lower groove 104 may provide fluid communication between inner bore 118 of spring mandrel 34 and valve chamber 138. In the closed position, valve chamber 138 may be formed between valve sleeve 20 and spring mandrel 34. The upper end of valve chamber 138 may be formed by lower end 74 of valve 30, and the lower end of valve chamber 138 may be formed by an upper surface of valve stop 22.
With reference again to
Upper spring ring 40 may be disposed around spring mandrel 34. An upper surface of upper spring ring 40 may directly engage a lower surface of seal block 120 of spring mandrel 34. A lower surface of upper spring ring 40 may directly engage an upper end of spring 36. Upper spring ring 40 may have a generally tubular shape with an inner diameter dimensioned to receive spring mandrel 34. An outer diameter of upper spring ring 40 may be sized to provide annular space 152 between outer surface 154 of upper spring ring 40 and inner bore 142 of spring sleeve 24.
Lower spring ring 38 may also be disposed around spring mandrel 34. An upper surface of lower spring ring 38 may directly engage a lower end of spring 36. A lower surface of lower spring ring 38 may directly engage spring sleeve shoulder 148. Lower spring ring 38 may have a generally tubular shape with an inner diameter dimensioned to received spring mandrel 34. An outer diameter of lower spring ring 38 may be sized to fit within inner bore 142 of spring sleeve 24 above spring sleeve shoulder 148.
Spring 36 applies an upward spring force on valve assembly 19. Specifically, spring 36 applies an upward force on upper spring ring 40, which transmits the upward spring force to seal block 120 of spring mandrel 34. Upper end 114 of spring mandrel 34 transmits the upward spring force to orifice ring 32, which transmits the upward spring force to valve 30 through inner shoulder 100. In other words, the spring force biases upper spring ring 40, spring mandrel 34, orifice ring 32, and valve 30 toward the closed position. The upward movement of valve assembly 19 may be limited by upper surface 72 of valve 30 engaging the lower surface of upper ring 26. The upward movement of valve assembly 19 may also be limited by the upper end of seal block 120 of spring mandrel 34 engaging a lower surface of valve stop 22. Because of this upward spring force, the default position of flow rate control system 10 with no fluid flow is the closed position shown in
Referring still to
The one or more upper nozzles 128 provide fluid communication between inner bore 118 of spring mandrel 34 and upper dampening chamber 160. The one or more lower nozzles 130 provide fluid communication between inner bore 118 of spring mandrel 34 and lower dampening chamber 162. When a fluid begins to flow through inner bore 118 of spring mandrel 34, a small portion of the fluid may flow through nozzles 128, 130 to fill upper and lower dampening chambers 160, 162, respectively. Upper and lower nozzles 128 and 130 may be configured to provide a volumetric fluid flow rate between inner bore 118 of spring mandrel 34 and upper and lower dampening chambers 160, 162. As valve assembly 19 moves up or down, the volumes of upper and lower dampening chambers 160 and 162 change. The rate at which the fluid moves in and out of the upper and lower dampening chambers 160 and 162 controls the rate at which valve assembly 19 moves between open and closed positions. In one embodiment, upper and lower nozzles 128 and 130 each include a reduced diameter portion to restrict fluid flow dependent on the sum of the forces acting on valve assembly 19 from spring 36 and the pressure differential created by fluid flow across valve assembly 19.
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In order for spring mandrel 34 to slide downward, a portion of the fluid in lower dampening chamber 162 must be returned to inner bore 118 of spring mandrel 34 through lower nozzles 130 and more fluid must enter upper dampening chamber 160 through upper nozzles 128. The restricted diameter of nozzles 128 and 130 delay the movement of valve assembly 19 in response to a change in the fluid flow rate. In this way, the dampening chambers provide a dampening effect on the movement of valve assembly 19. Valve assembly 19 slides in response to average fluid flow rates over time as opposed to changes of short duration or quicker fluctuations. Fluid in valve chamber 138 must also return to inner bore 118 of spring mandrel 34 as valve 30 and spring mandrel 34 slide downward.
Valve assembly 19 slides downward in response to increasing fluid flow rates until reaching a partially open position illustrated in
With flow rate control system 10 in the partially open position, a portion of the fluid flowing through upper ring 26 is diverted through the bypass fluid path and into annulus 192. The diverted fluid may assist in clearing cuttings from wellbore annulus 192. Additionally, the diverted fluid flow may reduce the flow rate of fluid flowing to drilling motor 182, thereby preventing damage to drilling motor 182 that may be caused by higher flow rates.
In the partially open position, a bypass fluid path is created that may include bypass bores 84, inner bypass chamber 110, bypass openings 58, outer bypass chamber 66, and housing bypass openings 41. As fluid is forced through the bypass fluid path by the pressure differential between the inner bore of flow rate control system 10 and the annular area 192 (shown in
The pressure in annulus 192 is lower than the pressure within the inner bore of flow rate control system 10 due to the pressure drop across the bottom hole assembly, including drilling motor 182 and drill bit 184. In the partially open position, the pressure inside the portion of inner bore 60 of valve sleeve 20 that is above surface 72 of valve sleeve 30 is greater than the pressure in inner bypass chamber 110 (i.e., the pressure below valve collar 76), which is fluidly connected to annulus 192. For this reason, flow rate control system 10 is pressure controlled in the partially open position. “Pressure controlled” means that changes, up or down, in a pressure differential between a pressure of fluid in the inner bore of flow rate control system and a pressure in an annulus surrounding flow rate control system cause the valve assembly 19 to slide from the partially open position to a fully open position or to the closed position, respectively (and to slide from the fully open position to the partially open position, as described below). In other words, when partially open or fully open, flow rate control system 10 is controlled by the pressure differential between the pressure in the inner bores of flow rate control system 10 and the pressure in annulus 192. If fluid flow slows or temporarily stops while the pressure differential across flow rate control system 10 and annulus 192 remains, valve assembly 19 will not return to the closed position even with the reduction or temporary elimination of fluid flow. When fluid flow is stopped for a longer time, internal fluid pressure may bleed off through the bypass fluid path until the force acting on second active valve area D is less than the upward force from spring 36 causing the valve to close.
With flow rate control system 10 in the partially open position, the pressure differential between the inner bore of upper ring 26 and annulus 192 acts on the second active valve area D to slide valve assembly 19 further in the downward direction. As valve assembly 19 slides further downward, more of the fluid in lower dampening chamber 162 is returned to inner bore 118 of spring mandrel 34 through lower nozzles 130 and more fluid enters upper dampening chamber 160 through upper nozzles 128. The restricted diameter of nozzles 128 and 130 delay the movement of valve assembly 19 in response to changes in the pressure differential. Dampening chambers 160, 162 provide a dampening effect to cause valve assembly 19 to slide in response to average pressure values over time as opposed to changes of short duration or quicker fluctuations. More fluid in valve chamber 138 must also return to inner bore 118 of spring mandrel 34 as valve 30 and spring mandrel 34 slide further downward from the partially open position.
Increasing pressure differentials between the inner bore of upper ring 26 and annulus 192 cause valve assembly 19 to continue to slide downward until reaching a fully open position illustrated in
Flow rate control system 10 is pressure controlled in the fully open position. If fluid flow slows or temporarily stops (e.g., due to a plugged drill bit or a stalled motor) while the pressure differential between flow rate control system 10 and annulus 192 remains, valve assembly 19 will not slide upward towards the closed position. In order to cause valve assembly 19 to slide upward and return to the closed position shown in
Because flow rate control system 10 is flow rate controlled in the closed position, it is automatically activated when a fluid flow rate exceeds a maximum allowed for drilling motor 182. Flow rate control system 10 is pressure controlled in the partially open position and the fully open position. Accordingly, after beginning to divert a portion of the fluid flow to annulus 192, flow rate control system 10 is not unintentionally closed by flow rate changes. Flow rate control system 10 is transferred to the closed position only in response to a predefined pressure change created at surface 188. Additionally, the dampening effect provided by the arrangement of nozzles 128, 130 and dampening chambers 160, 162 prevents flow rate control system 10 from being unintentionally opened or closed due to pressure pulses, vibration, bit plugging, or motor stalling. In one embodiment, the dampening effect may effectively require a flow rate change or pressure change to be maintained for 30-45 seconds before the flow rate control system 10 changes positions (i.e., between the closed position and the partially open position, or between the partially open position and the fully open position).
Flow rate control system 10 is configured to reach the partially open position (in
In an alternate embodiment, upper and lower dampening chambers 160, 162 may be prefilled with a fluid, such as an oil or drilling fluid.
In another alternate embodiment, upper and lower nozzles 128, 130 may be replaced by one or more nozzles extending axially through seal block 120 to fluidly connect upper and lower dampening chambers 160, 162. In this embodiment, fluid flows directly from lower dampening chamber 162, through the nozzles, and into upper dampening chamber 160 as valve assembly 19 travels in the downward direction. Conversely, fluid flows directly from upper dampening chamber 160, through the nozzles, and into lower dampening chamber 162 as valve assembly 19 travels in the upward direction. The nozzles and dampening chambers provide a dampening effect to slow the movement of valve assembly 19 between the closed position, the partially open position, and the fully open position.
In another alternate embodiment, flow rate control system 10 may include only one dampening chamber. In this embodiment, a seal may be eliminated to allow fluid flow into a space on the opposite side of seal block 120.
In another alternate embodiment, the valve bypass bores 84 may extend radially from inner bore 98 of valve 30 through to lower collar surface 78, reduced diameter section 90, or lower valve shoulder 92 of valve 30.
In yet another alternate embodiment, one or more parts of the valve assembly may be integrally formed or may be split into separate parts. In one example, the orifice ring and the spring mandrel may be integrally formed of a single piece. In another example, the valve, the orifice ring, and the spring mandrel may be integrally formed of a single piece. In another example, the spring mandrel may be formed of two or more separate pieces that are secured together. In another example, the valve may be formed of two or more separate pieces that are secured together. Additionally, one or more parts of the sleeve assembly may be integrally formed or may be split into separate parts. In one example, the valve stop and the spring sleeve may be integrally formed of a single piece. In another example, the valve sleeve, the valve stop, and the spring sleeve may be integrally formed of a single piece. In another example, the spring sleeve may be formed of two or more separate pieces that are secured together. In another example, the valve sleeve may be formed of two or more separate pieces that are secured together.
In a further alternate embodiment, the flow rate control system may include a valve assembly without a sleeve assembly such that valve assembly slides directly within a housing inner bore.
In a further alternate embodiment, the flow rate control system may include a valve assembly that completely closes the flow of the drilling fluid through the mud motor below, thereby bypassing all drilling fluid to the annulus outside of the housing of the flow rate control system. In this complete bypass position, the drilling fluid can be changed to different fluids, such as LCM fluid, perforating fluid, or fracking fluid.
Flow rate control system 10 prevents drilling motor 182 from being exposed to a fluid flow rate that is higher than a maximum allowable flow rate by providing a bypass flow through the bypass fluid path when the flow rate in flow rate control system 10 exceeds the maximum allowable flow rate. For example, but not by way of limitation, if a drilling motor is rated for a maximum drilling fluid flow rate of 600 GPM, flow rate control system 10 may divert 300 GPM through the bypass fluid path when the drilling fluid flow rate in flow rate control system 10 reaches 900 GPM. In an alternate example, but not by way of limitation, if the maximum design flow rate of a drilling motor is 600 GPM, flow rate control system 10 may divert 100 GPM through the bypass fluid path when the drilling fluid flow rate in flow rate control system 10 reaches 700 GPM.
Except as otherwise described or illustrated, each of the components in this device has a generally cylindrical shape and may be formed of steel, another metal, or any other durable material. Portions of flow rate control system 10 may be formed of a wear resistant material, such as tungsten carbide or ceramic coated steel. In one embodiment, the portions of valve 30 and valve sleeve 20 at interface 108 (shown in
Each device described in this disclosure may include any combination of the described components, features, and/or functions of each of the individual device embodiments. Each method described in this disclosure may include any combination of the described steps in any order, including the absence of certain described steps and combinations of steps used in separate embodiments. Any range of numeric values disclosed herein includes any subrange therein. “Plurality” means two or more. “Above” and “below” shall each be construed to mean upstream and downstream, such that the directional orientation of the device is not limited to a vertical arrangement.
While preferred embodiments have been described, it is to be understood that the embodiments are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalents, many variations and modifications naturally occurring to those skilled in the art from a review hereof.
