Embodiments usable within the scope of the present disclosure relate, generally, to bypass systems usable to divert and/or bypass the flow of drilling mud past a power section of a drilling motor. And more specifically, embodiments relate to flow control and/or interior valves usable to release pressure within a drill string above a drilling motor.
Drilling companies drill wellbores all over the world to extract water, hydrocarbons, or other useful materials from production zones that are sometimes many thousands of feet underground. To drill wellbores, drilling rigs often employ a rotating drill bit, which may be attached at the end of a string of tubulars. The rotating drill bit may include teeth at the bottom end that break up the rock. The broken rock can then be taken away to the surface. In some instances, the drilling rig rotates the entire string of tubulars from the surface of the wellbore. During other operations, however, the drill string remains rotationally stationary while the drill bit is rotated using a downhole motor (e.g., a progressive cavity positive displacement motor). Downhole motors may rotate an associated drill bit in response to the flow of drilling mud through the motor. The drilling mud may be pumped from the surface of the wellbore through the tubulars into a stator housing of the downhole motor. The pressure of the drilling fluid causes a rotor within the stator housing to rotate. The rate at which the borehole can be extended, often referred to as the ROP (rate of penetration), can be increased, in some circumstances, by increasing the amount of pressure delivered to the downhole motor.
In operations where a downhole motor is used, operators may often attempt to increase the ROP by increasing the load on the motor in excess of the tolerance of the downhole motor. If the motor lacks sufficient horsepower or momentum to continue the drilling operation, the motor may stall. In other situations, the characteristics of the formation or damage to the drill bit can contribute to stalling of the motor. During a stall, the drill bit stops rotating, and if drilling fluid is continuously provided to the downhole motor, a differential pressure across the motor can become extremely high. A differential pressure that is too high can cause severe damage to the motor, or some components of the motor (e.g., rubber, composite, elastomeric liner of the stator housing, and/or the flex shaft or tie-rod).
Stalls can often be mitigated by an operator, if a signal or indication of the pressure differential is communicated to the surface, and the operator responds to the signal or indication. Operators, however, can sometimes be unresponsive to the signal, or they can be influenced by the incentive to maximize the ROP in spite of the risk of a stall. Additionally, a drill bit may stall no matter what the operator does, if the formation varies in hardness or composition. Devices can be used to reduce the damage caused by a stall by absorbing or dampening forces from the drilling mud. However, many mechanical and electronic devices are prone to damage and/or failure. Additionally, mechanical forces used by such devices (e.g., rapid extension of springs, constant wearing of reciprocal movement) can cause damage to threaded connections, tools, and other components, interfering with measurements in instruments and sensors in the bottomhole assembly, and potentially un-torqueing connections in the tubular string. Devices occupy precious space within the tubular string, which can make them unsuitable for use within smaller strings and wellbores.
Further, the devices within a tubular string shunt the drilling fluid to the outside of the tubular string to relieve the excessive pressure from above the drilling motor. Shunting, however, can cause additional other problems. For example, the tubular string may include other drilling tools downhole from the downhole motor. These tools may include directional drilling, cutting removal, or other tools that depend on fluid pressure to function properly. If drilling fluid is shunted outside the tubular string, less of the fluid will be used to power those downhole tools.
A need exists for devices and methods usable to control the flow of drilling fluid through a power section of a downhole motor to reduce the likelihood of a stall and/or minimize damage to components should a stall occur.
A need also exists for devices and methods usable to power further downhole tools, while bleeding excess pressure from above the power section of a downhole motor.
Embodiments usable within the scope of the present disclosure meet these needs.
Embodiments usable within the scope of the present disclosure include a drilling motor for providing rotational force within a wellbore. The drilling motor includes a housing including an interior and an exterior, wherein the housing is configured to connect to a drill string that receives pressurized drilling mud from the surface of the wellbore, a power section within the interior of the housing, wherein the power section includes a sealing elastomer, a rotor positioned within the power section, wherein the rotor includes rotor lobes within the power section configured to rotate in response to pressure from the pressurized drilling mud, a passage within the rotor, wherein the passage is configured to bypass a portion of the drilling mud from above the power section within the interior of the housing to below the power section within the interior of the housing, an interior valve, wherein the valve is configured to provide a closing force that closes the passage when the pressure from the pressurized drilling mud is less than a threshold pressure, and to pass drilling mud through the valve when the pressure from the pressurized drilling mud is greater than the threshold pressure.
Certain embodiments may also include an adjustment member configured to adjust the closing force. The adjustment member includes an adjustment screw configured to raise the closing force when screwed in a first direction, and lower the closing force when screwed in a second direction. The passage may be located through a center of the rotor. The valve may include a valve nozzle, a spring, and a ball, wherein the spring forces the ball against the nozzle to close the passage. The valve may include a plurality of bypasses configured to disperse the drilling mud passing through the valve into an annulus below the power section. The plurality of bypasses may include an angle of travel that is less than 90 degrees with respect to an axis of the drilling motor. The plurality of bypasses may include a first bypass with an opening at a first longitudinal location, and a second bypass with an opening at a second longitudinal location.
Certain embodiments may also include a method for relieving pressure in a drilling motor. The method may include receiving drilling mud to the drilling motor through a drilling string, rotating a rotor of the drilling motor, wherein the rotor rotates within a power section of a housing of the drilling motor in response to a pressure provided by the drilling mud, opening an interior valve within the drilling motor when the pressure is above a threshold pressure, wherein opening the valve bypasses a portion of the drilling mud through a passage within the rotor, wherein the passage flows from above the power section within the housing to below the power section within the housing, and closing the valve when the pressure is below the threshold pressure.
Certain embodiments of the method may also include depressing a spring loaded ball valve and/or dispersing the drilling mud through a plurality of bypasses after the drilling mud flows through the passage. The method may include tuning an adjustment member to adjust the threshold pressure at which the valve opens and/or powering a downhole tool with drilling mud below the power section of the drilling motor. Powering the downhole tool may include powering a drill bit, a reamer, a MWD, an LWD, a pulser valve, a rotary steerable, any other downhole tool, or any combination thereof. The method may also include forcing the drilling mud from a drill bit nozzle, wherein all the drilling mud is forced through the drill bit nozzle.
Certain embodiments may also include a system for drilling a well. The system may include drill string configured to convey drilling mud from a surface pump, a drilling motor connected to the drill string. The drilling motor may include a housing including an interior and an exterior, wherein the housing is configured to connect to a drill string that receives pressurized drilling mud from the surface of the wellbore, a power section within the interior of the housing, wherein the power section includes a sealing elastomer, a rotor positioned within the power section, wherein the rotor includes rotor lobes within the power section configured to rotate in response to pressure from the pressurized drilling mud, a passage within the rotor, wherein the passage is configured to bypass a portion of the drilling mud from above the power section within the interior of the housing to below the power section within the interior of the housing, a valve below the passage, wherein the valve is configured to provide a closing force that closes the passage when the pressure from the pressurized drilling mud is less than a threshold pressure, and to pass drilling mud through the valve when the pressure from the pressurized drilling mud is greater than the threshold pressure, a drill bit connected to, and configured to rotate with, the rotor, wherein the drill bit includes drilling nozzles that spray the drilling mud, and an additional downhole tool configured to be powered by the drilling mud.
In the detailed description of various embodiments usable within the scope of the present disclosure, presented below, reference is made to the accompanying drawings, in which:
One or more embodiments are described below with reference to the listed figures.
Before describing selected embodiments of the disclosure in detail, it is to be understood that the disclosure is not limited to the particular embodiments described herein. The disclosure and description herein is illustrative and explanatory of one or more example embodiments, and it will be appreciated by those skilled in the art that various changes in the design, organization, order of operation, means of operation, equipment structures and location, methodology, and use of mechanical equivalents may be made without departing from the spirit of this disclosure.
As well, it should be understood the drawings are intended to illustrate and disclose example embodiments to one of ordinary skill in the art, but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation. As well, the relative size and arrangement of the components may differ from that shown and still operate within the spirit of this disclosure as described herein.
Moreover, it will be understood that various directions such as “upper”, “lower”, “bottom”, “top”, “left”, “right”, and so forth are made only with respect to explanation in conjunction with the drawings, and that the components may be oriented differently, for instance, during transportation and manufacturing as well as operation. Because many varying and different embodiments may be made within the scope of the inventive concept(s) herein taught, and because many modifications may be made in the embodiments described herein, it is to be understood that the details herein are to be interpreted as illustrative and non-limiting.
The drilling system 10 depicted in
In the illustrated embodiment, the power section 44 includes a sealing elastomer 50 and rotor lobes 52. Various configurations may be used for the shape and configuration of the sealing elastomer 50 and rotor lobes 52. Whatever the configuration, as the drilling mud 36 flows from a higher pressure area 54 above the power section 44 to a lower pressure area 56 in an annulus 58 below the power section 44, the rotor 40 converts the pressure and motion into rotation. The difference between the higher pressure in the higher pressure area 54 and the lower pressure in the lower pressure area 56 may be 500-5000 psi, 1500-4500 psi, 2000-2500 psi, or other ranges depending on the size and shapes of the drilling system 10, drilling motor 12, wellbore, and the characteristics of the rock formations that are being drilled. The rotational speed of the rotor 40 may increase with an increase in pressure in the higher pressure area 54, but only to a certain point. Operators at the surface of the wellbore may increase the pressure beyond the capability of the rotor 40 to convert into rotational energy. That is, at a certain point increasing the pressure of the drilling mud 36 starts to degrade the components within the interior 34 of the drilling motor 12. Specifically, the sealing elastomer 50, which may be made out of polymers or rubber, may wear out prematurely if the pressure is too high. In certain embodiments, the drilling motor 12 may include release valves or sleeve valves that jettison drilling mud 36 from the higher pressure area 54 to the exterior 32 before the drilling mud 36 can damage the sealing elastomer 50. These embodiments, however, can suffer from the lack of drilling mud 36 below the rotor 40, decreasing the ability of the downhole tools 24 to function with full power, and the ability of the nozzles 16 to sufficiently convey the cuttings from the drill bit 14.
The illustrated embodiment includes a passage 60 within the rotor 40 of the power section 44 that enables the drilling mud 36 to bypass the power section 44 and remain within the interior 34 so that the downhole tools 24 and the nozzles 16 may work at full efficiency. The passage 60 may begin at a top end of the rotor catch mechanism 42, as illustrated, but may also include an opening through the rotor catch mechanism 42, or other components of the rotor 40 above the power section 44. The flow of drilling mud 36 through the passage 60 can be controlled by an interior valve 62 that mechanically stops the flow of drilling mud 36 until the pressure in the higher pressure area 54 reaches a threshold pressure. If the drilling mud 36 has a pressure below the threshold pressure, the interior valve 62 remains closed and no drilling mud 36 passes through the passage 60. If the drilling mud 36 rises in pressure above the threshold pressure, then the interior valve 62 will open up, and drilling mud 36 will flow through the passage 60, bypassing the rotor 40 of the power section 44.
If at some future time the pressure of the drilling mud 36 drops below the threshold pressure, the interior valve 62 closes once again, and all of the drilling mud 36 will flow through the power section 44 once more. This cycle of opening and closing the interior valve 62 may occur multiple times during the drilling of a wellbore. For example, a single wellbore may pass through a multitude of rock layers that each have varying degrees of hardness. If the drilling system 10 drills through a relatively softer rock layer and encounters a relatively harder rock layer, the drill bit 14 may slow down, causing the pressure to rise within the drill string 15. Before the increased pressure damages the sealing elastomer 50, however, the interior valve 62 opens and bypasses drilling mud 36 through the passage 60 until an operator responds, or the drilling system 10 drills through the harder rock layer.
Once the interior valve 62 is open, the drilling mud 36 flows through the valve nozzle 64 and out through a first bypass 68 (also shown in
While various embodiments usable within the scope of this disclosure have been described with emphasis, it should be understood that within the scope of the appended claims, the invention can be practiced other than as specifically described herein.
The present application is a non-provisional utility application claiming priority to U.S. Provisional Patent Application No. 62/542,259, entitled “Drilling Motor Interior Valve” and filed 7 Aug. 2017, and U.S. Provisional Patent Application No. 62/560,556, entitled “Drilling Motor Interior Valve” and filed 19 Sep. 2017. The contents of both provisional applications are incorporated herein by reference.
Number | Date | Country | |
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62542259 | Aug 2017 | US | |
62560556 | Sep 2017 | US |