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    • 专利摘要:
    bearing section for a mud engine. a mud motor bearing unit has a mandrel rotatably arranged in a cylindrical housing, with a rolling element thrust bearing arranged within an annular chamber sealed with oil, between the mandrel and the housing, to resist loads axial thrust at the base. axial thrust loads outside the bottom are resisted by a mud lubricated thrust bearing unit, located above the oil-sealed chamber. the lower end of a driveshaft adapter coupled to the mandrel is used to provide an upper load transfer shoulder for the thrust bearing off the bottom, with a lower load transfer shoulder being provided in association with the housing. the upper and lower shoulders come into contact under the thrust load outside the bottom, with the upper rotating shoulder (with the mandrel) relative to the lower shoulder.
    公开号:BR112013019051B1
    申请号:R112013019051-5
    申请日:2012-01-26
    公开日:2020-09-15
    发明作者:Nicholas Marchand
    申请人:National Oilwell Varco, L.P；
    IPC主号:
    专利说明:

    FIELD OF THE INVENTION
    [0001] The invention concerns, in general terms, bearing units for mud engines used in drilling oil, gas and water wells. More particularly, the invention concerns mud motor bearings to withstand thrust loads at the bottom and outside the bottom. TECHNICAL FUNDAMENTALS
    [0002] When drilling a well bore in the earth, such as for the recovery of hydrocarbons or minerals from a subsurface formation, it is conventional practice to connect a drill to the lower end of a unit of drill pipe sections connected end to end (commonly called a “drill string”) and then rotate the drill string so that the drill bit advances down into the earth to create the desired borehole. In conventional vertical borehole drilling operations, the drill string and drill bit are rotated by means of a “rotary table” or a “top transmission” associated with a drilling rig raised on the surface of the earth over the borehole. well (or offshore drilling operations, on a drilling platform supported by the seabed or in a suitably adapted floating vessel).
    [0003] During said drilling process, a drilling fluid (also commonly known in the industry as "drilling mud", or simply "mud") is pumped under pressure under the surface through the drill column, out of the drill, into the well hole and then upward back to the surface, through the annular space between the drill string and the well hole. The drilling fluid, which can be water-based or oil-based, is typically viscous for increasing its ability to transport borehole chips to the surface. The drilling fluid can perform a number of other valuable functions, including increasing drill performance (for example, by ejecting the fluid under pressure through the drill holes, creating jets of mud that collide with and weaken the underlying formation before the drill) , cooling the drill and forming a protective pie in the well hole wall (to stabilize and seal the well hole wall). To optimize these functions, it is desirable that as much of the drilling fluid as possible reach the drill bit.
    [0004] In particular, since the mid-1980s, it has become common and desirable and increasingly in the oil and gas industry to use “directional drilling” techniques to drill horizontal and other non-vertical well holes to facilitate more efficient access the production of larger regions of formations containing subsurface hydrocarbons that would not be possible using only vertical well holes. In directional drilling, specialized drill string components and “borehole units” (BHAS) are used to induce, monitor and control deviations in the drill path in order to produce a well hole of the desired non-vertical configuration.
    [0005] Directional drilling is typically performed using a “downhole motor” (alternatively referred to as a “mud motor”) embedded within the drill string, immediately above the drill. A typical mud engine includes several primary components, as follows (in order, starting from the top of the engine unit): • a sub top adapted to facilitate connection to the lower end of a drill string (“sub” being the general and common term in the oil and gas industry for any small and / or secondary drilling column component); • a force section comprising a positive displacement motor of a well-known model, with a helical vane rotor, eccentrically rotating within a stator section; • a driveshaft included in a driveshaft housing, with the upper end of the driveshaft being operably connected to the rotor of the power section; and • a bearing section comprising a coaxial cylindrical mandrel rotatably arranged within a cylindrical housing; with an upper end coupled to the lower end of the drive shaft; and a lower end adapted for connection to a drill. Typically, coupling to the drive shaft is performed by providing the upper end of the mandrel with a threaded “pin” connection, which screws into the connection “box” connection of an adapter associated with the lower end of the drive shaft unit. .
    [0006] In drilling processes using a mud motor, the drilling fluid is circulated under pressure through the drilling column and back to the surface, as in conventional drilling methods. However, the pressurized drilling fluid, leaving the lower end of the drill pipe, is deflected through the force section of the mud motor, to generate force to rotate the bit.
    [0007] The bearing section must allow relative rotation between the mandrel and the housing, while also transferring axial thrust loads between the mandrel and the housing. Axial thrust loads come in two operational drilling modes: “bottom” load and “bottom” load. Bottom load corresponds to the operational mode during which the drill is drilling in a subsurface formation under vertical load of the weight of the drill string, which in turn is in compression; in other words, the drill is at the bottom of the borehole. Off-bottom loading corresponds to the operational modes in which the drill is raised from the bottom of the well hole and the drill column is in tension (that is, when the drill is off the bottom of the well hole and is hanging from the drilling, such as when the drill string is being "displaced" out of the well hole, or when the well hole is being widened in the direction above the hole). Stress shits through the housing of the bearing section and the mandrel are also induced when drilling fluid is circulated with the drill out of the bottom, due to pressure drop through the drill and bearing unit.
    [0008] Therefore, the bearing section of a mud motor must be able to withstand the thrust loads in both axial directions, with the mandrel rotating inside the housing. One mud motor bearing section can be configured with one or more bearings that resist only buoyant loads in the bottom and with another one or more bearings that resist buoyant loads out of the bottom only. Alternatively, one or more bidirectional thrust bearings can be used to withstand loads on both the bottom and the bottom. A typical thrust bearing unit comprises bearings (commonly, but not necessarily rod bearings contained within a bearing housing) disposed within an annular bearing containment chamber. Suitable radial bearings (for example, trunnion bearings or sleeve bearings) are used to maintain coaxial alignment between the mandrel and the bearing housing.
    [0009] The thrust bearings contained in the bearing section of a mud engine can be lubricated with oil or lubricated with mud. In an oil-sealed bearing unit, thrust bearings are disposed within an oil-filled reservoir to provide a clean operating environment. The oil reservoir is located within an annular region between the mandrel and the housing, with the reservoir being defined by the internal surface of the housing and the external surface of the mandrel and by sealing elements at the upper and lower ends of the reservoir.
    [00010] Mud-lubricated bearing units comprise bearings that are designed for operation in drilling fluid (“mud”). A small portion of the drilling fluid flowing into the bit is diverted to flow through the bearings to provide lubrication and cooling.
    [00011] Oil sealed bearing units offer several advantages over mud lubricated bearing units. Due to the clean operating environment, oil-sealed components tend to have a longer service life. Since conventional mud lubricated bearing units require a portion of the drilling fluid to be diverted through the bearings and into the annular crown of the well hole, the total flow of fluid through the drill is reduced, thereby reducing efficiency the drilling fluid hydraulics through the drill. Oil-sealed units do not require drilling fluid to be bypassed and can be configured so that all drilling fluid is directed through the drill, thus optimizing the drilling fluid hydraulics through the drill. This can be particularly advantageous when passing additional drilling tools between the mud motor and the drill, such as a rotary steer system, where the total flow of the drilling fluid to the tool is required for optimal operation.
    [00012] However, mud-lubricated bearings have their own advantages. In particular, mud-lubricated bearings with flat bearing contact surfaces, can provide considerably greater static thrust load capacities than are obtained with conventional rolling element bearings. In addition, mud-lubricated bearings can operate reliably in harsh environments, without the need for a sealed bearing chamber.
    [00013] As previously noted, separate thrust bearings can be used for thrust loads on the bottom and off the bottom, or bidirectional thrust bearings can be used to withstand thrust loads both on the bottom and off the bottom. In any case, the mandrel must incorporate a load transfer cam located above the bearing outside the bottom, to transfer loads outside the mandrel bottom to the housing. This is commonly accomplished in bearing units through the use of a machined ring with a formation of high-tolerance annular grooves and ribs, dimensioned to join with the corresponding high-tolerance annular ribs and grooves in the mandrel. The ring is necessarily provided in the form of a slotted ring, to allow mounting on the mandrel. When mounted on the mandrel, the slotted ring provides the necessary shoulder for off-bottom loads, which are transferred from the non-bottom thrust bearing (or, alternatively, a bidirectional thrust bearing) to the mandrel through the annular grooves and ribs. mandrel and slotted ring union. The spacing of the grooves and ribs in the mandrel and the slotted ring must be very precise, so that the axial load is shared equally between each adjacent set of groove faces / joining ribs.
    [00014] A bearing rod bearing (that is, a bearing incorporating any type of bearing rod, such as spheres, cylindrical rollers, tapered roles and spherical rollers) will have static and dynamic load ratings that define allowable load limits during operation. A thrust bearing out of the bottom can experience high static loads if the drill bogs into the well hole and the drill column needs to be tensioned in an attempt to release the drill. If the static load limit of the bearing outside the bottom is exceeded, the engine will not be operable once the drill bit is released and the engine will not need to be removed from the well hole and replaced before drilling can continue.
    [00015] For at least the reasons discussed above, there remains a need in the art for an oil sealed mud motor bearing section, in which the mandrel is provided with a load transfer shoulder to react to thrust loads outside the but without the need for high tolerance machining of the mandrel and associated shoulder components. In addition, there remains a need in the art for a mud motor bearing section incorporating a thrust bearing out of the bottom, having a much higher static load limit than that provided by roller rod bearings. Furthermore, there remains a need in the art for a mud motor bearing section incorporating a mud-lubricated outside bearing unit, in which the flow of mud through the outside bearing unit is returned to the main mud flow. through the bearing section, instead of exiting into the annular crown of the well bore and thereby reducing the total mud flow reaching the drill. The embodiments described here are aimed at such needs. BRIEF DESCRIPTION SUMMARY
    [00016] The embodiments described here generally show mud motor bearing unit having an oil sealed bearing chamber, which houses at least one oil sealed thrust bearing, to withstand bottom thrust loads, with loads thrust bearings off the bottom being resisted by a mud lubricated thrust bearing, disposed inside an off bottom thrust bearing chamber located above the oil sealed bearing chamber. The axial loads acting on the bearing units are resisted by the radial bearings located inside the oil-sealed chamber. Being sealed with oil, the radial bearings and the thrust bearing at the bottom are in an optimal operating environment and there is no need to divert any drilling mud through the thrust bearing chamber at the bottom. The drilling mud used to lubricate and cool the thrust bearing off the bottom gathers the mud flow with the bit, instead of being discharged into the annular crown of the well hole.
    [00017] In accordance with the embodiments described here, the lower end of a driveshaft adapter connected to the mandrel effectively serves, directly or through an intermediate structure, as the required load transfer shoulder in association with the mandrel for transfer of buoyant loads out of the bottom. This eliminates the need for an intermediate support shoulder along the mandrel, such as the slotted ring shoulder used in prior art units, thus eliminating the need for high-tolerance machining required by such slotted ring shoulders. In addition, the use of the driveshaft adapter to transfer thrust loads off the bottom shortens the total length of the bearing unit. In addition, by eliminating the use of a rolling rod bearing for off-bottom thrust loads, the static load limit of the off-bottom thrust bearing unit is significantly increased, so that when the drill string is being pulled to release a jammed bit, there is little or no risk of overloading the thrust bearing off the bottom and thus rendering the mud engine inoperable after the bit has been released.
    [00018] Accordingly, those embodiments described here show a bearing section for a mud motor, comprising an elongated mandrel, rotatable and coaxially disposed within an elongated cylindrical housing, a first (or higher) annular bearing chamber, laterally limited by the external surface of the mandrel, the internal surface of the housing, an annular contiguity associated with the housing and the lower end of a cylindrical drive shaft adapter, fixed to the upper end of the mandrel; and a mud-lubricated thrust bearing unit, disposed within the first bearing chamber, so that the mud-lubricated thrust bearing unit which in compression between the annular contiguity and the drive shaft adapter, when the bearing is under tension, thus resisting buoyant loads outside the bottom. The mandrel is generally cylindrical, with a central hole for the passage of the drilling mud, and a generally cylindrical wall. One or more mud holes are formed through the mandrel wall, so that the drilling mud, flowing through the first bearing chamber, to lubricate and cool the thrust bearing unit, will exit the bearing chamber through the one or more mud holes, joining the main drilling mud stream, through the central chuck hole and down to the drill bit.
    [00019] In alternative embodiments, the bearing section also incorporates an annular oil reservoir limited by the external surface of the mandrel, the internal surface of the housing and the upper and lower rotating seals between the mandrel and the housing. A part of the oil reservoir defines a second (lower) annular bearing chamber, limited at its lower end by an annular lower shoulder associated with the mandrel, and at its upper end by an annular upper shoulder associated with the housing. A thrust bearing is disposed within the second bearing chamber, so that it is in compression between the upper and lower projections, when the bearing section is in compression, thereby resisting thrust loads at the bottom.
    [00020] In some embodiments, the bearing section also incorporates a mud lubricated radial bearing unit, disposed within the first (or higher) bearing chamber.
    [00021] Thus, the embodiments described here comprise a combination of details and advantages designed to address various deficiencies associated with certain devices, systems and methods. The various features described above, as well as other details, will be readily apparent to those skilled in the art when reading the following detailed description and by reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
    [00022] For a more detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings, in which: Figure 1 is a longitudinal cross section through the bearing section of a prior art mud motor, showing thrust bearings in the bottom and outside the bottom, with load transfer shoulders with associated slotted ring. Figure 1A is an enlarged view of the bearing chamber of the prior art section of Fig. 1, with the bearing section operating under buoyant load at the bottom; Figure 2 is a longitudinal cross section through the bearing section of an embodiment of a mud motor incorporating a thrust bearing unit off the bottom, according to the principles described here; Figure 3A is an enlarged view of that thrust bearing unit off the bottom of Figure 2, as configured when the bearing section is operating under conditions of thrust load off the bottom; and Figure 3B is an enlarged view of the thrust bearing unit off the bottom of Figure 2, indicating the flow path for the drilling fluid through the thrust bearing unit off the bottom. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
    [00023] The argument below is intended for various embodiments of the invention. Although one or more of said embodiments may be preferred, the described embodiments are not to be interpreted, or otherwise used as limiting the scope of the description, including the claims. In addition, a person skilled in the art will understand that the following description has wide application and argumentation of any embodiment is intended only to be exemplary of that embodiment, and is not intended to imply that the scope of the description, including its claims, they are limited to that embodiment.
    [00024] Certain terms are used throughout the following description and claims to refer to particular details or components. As a person skilled in the art will appreciate, different people may refer to the same detail or component by different names. This document is not intended to distinguish between components or details that differ in name, but in function. The drawing figures are not necessarily to scale. Certain details and components here may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interests of clarity and conciseness.
    [00025] In the following discussion and in the claims, the terms "including" and "comprising" are used in an unlimited manner, and thus should be interpreted to mean "including, but not limited to ...". Also, the term “couple” or “couple” is intended to mean an indirect or direct connection. Thus, if a first device is coupled to a second device, that connection can be through a direct connection, or through an indirect connection, via other devices, components and connections. In addition, as used herein, the terms "axial" and "axially" generally mean along or parallel to a central geometric axis (for example, central axis of a body or an orifice), while the terms "radial" and " radially ”generally mean perpendicular to the central geometric axis. For example, an axial distance refers to a distance measured along or parallel to the central geometric axis and a radial distance means a measured distance perpendicular to the central geometric axis.
    [00026] Figures 1 and IA illustrate an oil sealed bearing unit from bearing section 10 of a conventional mud motor. The bearing section 10 includes a mandrel 20 having an upper end 20U, a lower end 20L and a generally cylindrical mandrel wall 23, defining a central hole 22, through which the drilling fluid can be pumped down into a drill bit ( (not shown) directly or indirectly connected to the lower end 20L of mandrel 20. Mandrel 20 is coaxial and rotatably arranged within a cylindrical housing 30, which will typically consist of multiple subsections (such as 30A, 30B, 30C, 30D in Figure 1 ) screwed together. The housing 30 has an upper end 30U, adapted for connection to the lower end of the drive shaft housing (not shown) of the mud motor, and a lower end 30L (through which the lower end 20L of the mandrel 20 protrudes ). The upper end 20U of the mandrel 20 is adapted for connection to the drive shaft (not shown) of the mud motor, so that the drive shaft will rotate the mandrel 20 within and with respect to housing 30.
    [00027] As best shown in Figure 1 A, an annular bearing chamber 25 is formed between the mandrel 20 and the housing 30, in a middle region of the bearing section 10. A part of the outer surface 21 of the mandrel 20 within the chamber housings 25 are machined to form a group of annular grooves 28 and ribs 29, which fit into a slotted ring 40, which has a lower annular shoulder 41L, an upper annular shoulder 41U and an internal cylindrical surface 47. The internal cylindrical surface 47 of the slotted ring 40 is machined to form a group of annular ribs 49 and grooves 48, which join in a precision tolerance fit with the annular grooves 28 and ribs 29 of the mandrel 20. The annular grooves 18 and 48 and ribs ring 29 and 49 must be machined with great precision for uniform transfer of axial thrust loads between the mandrel 20 and the slotted ring 40. The slotted ring 40 is held in a radial position on the mandrel 20 by means of a retaining ring 42 , position in an annular recess 44 of the slotted ring 40 and held in position axially by a pressure ring 46.
    [00028] A lower thrust bearing lubricated with oil 50, with lower bearing track 51L and upper bearing track 51U, is disposed inside the bearing chamber 25 below and immediately adjacent to the lower shoulder 41L of the ring with slot 40. Shims 55 can be provided as shown in association to facilitate the positioning of the bearing 50 within the bearing chamber 25. The thrust loads outside the bottom (traction) are transferred from the mandrel 20 to the slotted ring 40 (via annular grooves 28 and 48 and annular ribs 29 and 49); thence via the lower shoulder 41L of the slotted ring 40 to the upper bearing track 51U, lower thrust bearing 50 and lower bearing track 51L; and thence to a lower shoulder 32 formed in the housing 30.
    [00029] An upper thrust bearing lubricated with oil 60, with lower bearing track 61L and upper bearing track 61U, is disposed inside the housing chamber 25 above and immediately adjacent to the upper shoulder 41U of the slotted ring 40. As best shown in Figure IA, thrust loads at the bottom (compressive) are transferred from mandrel 20 to the ring with slit 40 (via annular grooves 28 and 48 and annular ribs 29 and 49); from there, via the upper shoulder 41U of the ring with slot 40 to the lower bearing track 61L, upper thrust bearing 60 and upper bearing track 61U; and from there to an upper shoulder 34 formed within the housing 30.
    [00030] Consequently, the bearing chamber 25 of the conventional bearing section 10, is defined by the outer surface 21 of the mandrel 20, inner surface 31 of the housing 30, lower shoulder 32 of the housing 30 and upper shoulder 34 within the housing 30. Between the bearing chamber 25 and the lower end 30L of the housing 30, a lower radial bearing (shown in the form of a lower bushing 24) is provided under the bearing chamber 25 in an annular space between the mandrel 20 and the housing 30, to provide radial support for the mandrel 20 when it rotates within the housing 30. Similarly, an upper radial bearing (shown in the form of a bushing 26) is provided above the bearing chamber 25 in an annular space between the mandrel 20 and the accommodation 30.
    [00031] The bearing section 10 of Figure 1 also includes an annularly configured piston 72, arranged and axially movable within a cylindrical chamber 70, located in a region above the bearing chamber 25. The piston 72 is part of a system of pressure compensation, whereby piston position 72 automatically adjusts to compensate for changes in oil volume due to temperature changes and gradual oil leakage associated with rotating seals. The bearing chamber 25 and the cylindrical chamber 70 are contained within an annular oil reservoir sealed at its lower end by a lower rotating seal 15 and at its upper end by seals associated with the piston 72.
    [00032] With reference now to Figure 2, an embodiment of a mud motor bearing section 100, incorporating a thrust bearing in the oil-sealed bottom and a thrust bearing outside the bottom lubricated with mud, according to the principles described here, is shown. Bearing section 100 includes mandrel 20 and housing 30, generically as described and illustrated with reference to bearing section 10 of Figure 1. In Figure 2, bearing section 100 is shown incorporating an alternative pressure compensation system, different of the system shown in Figure 1, with the plunger 72 disposed within a cylindrical chamber 70, formed by a sleeve 74, not rotatably fixed in the housing 30. This alternative pressure compensation system is described in US Patent Application Serial No. 12 / 985,703, filed on January 8, 2011 and entitled “Pressure Compensation System For An Oil-sealed Mud Motor Bearing Assembly”, which is incorporated herein by reference in its entirety. The embodiments of the thrust bearing units off the bottom, in accordance with the principles described here, are particularly well suited for use in conjunction with those pressure compensation systems that are alternative. However, it should be understood that the embodiments described here are independent of and are in no way limited or restricted by any pressure compensation system incorporated in the mud motor bearing section incorporating the bearing units.
    [00033] As shown in Figure 2, bearing section 100 incorporates a thrust bearing at the bottom sealed with oil 60, with lower bearing track 61L and upper bearing track 61U, arranged within an annular lower bearing track 125 between the mandrel 20 and the housing 30. The thrust loads on the bottom (compressive) are transferred from the mandrel 20 to the lower bearing track 61L via a load transfer shoulder 27, formed on the mandrel 20 and, from there, into the housing 30, through thrust bearing 60, upper bearing track 61U and a load transfer shoulder 34, associated with housing 30 (for example, in the embodiment shown in Figure 2, the lower end of sleeve 74 serving as boss 34). In this way, the lower bearing chamber 125 of the bearing section 100 is defined by the outer surface 21 of the mandrel 20, inner surface 31 of the housing 30, shoulder 27 on the mandrel 20 and shoulder 34 on the housing 30.
    [00034] A lower radial bushing 24 is provided below the lower bearing chamber 125 in an annular space between mandrel 20 and housing 30, to provide radial support for mandrel 20 when it rotates within housing 30. Similarly, a upper radial bushing 26 is provided on top of the lower bearing chamber 125. The lower bearing chamber 125 and the cylindrical chamber 70 are contained within an annular oil reservoir sealed at its lower end by a lower rotating seal 125 between the mandrel 20 and housing 30, and at its upper end by an upper rotary seal 135 between mandrel 20 and housing 30
    [00035] As shown in Figure 2, the lower end of a cylindrical driveshaft housing 90 is screwed into the upper end 30U of housing 30 and the lower end of a driveshaft adapter 92 disposed within the driveshaft housing cylindrical 90 is screwed on the upper end 20U of mandrel 20 (as indicated by threaded connection 91). The cylindrical lower end of the drive shaft adapter 92 defines an annular contiguity 93 surrounding the upper end 20U of the mandrel 20. A drive shaft housing annular ring 97 is formed between the cylindrical drive shaft housing 90 and the drive adapter. drive shaft 92. The drive shaft adapter 92 is formed with mud flow channels 99 through which drilling mud can flow from the drive shaft housing ring 97 to the central hole 22 of the mandrel 20.
    [00036] Figures 3A and 3B illustrate an embodiment of an off-the-bottom thrust bearing unit 80 in accordance with the principles described here and also incorporating an optional radial bearing unit 140 (described in more detail below) . The thrust bearing unit off the bottom 80 is arranged within an annular upper bearing chamber 81 between the mandrel 20 and the housing 30. A lower load transfer shoulder, associated with the housing 30, is provided in the form of a annular lower thrust bearing track 82 fixed to the upper end of an annular contiguity 35 forming part of the housing 30, using suitable fixing means (such as by means of non-limiting example, pressure fitting or plug-in bearing track) shrinkage 82 within housing 30, or by using anti-rotation locking pins between bearing track 82 and housing 30), whereby relative rotation between lower thrust bearing track 82 and housing 30 is avoided. The lower thrust bearing track 82 has a flat top face 82U transverse to the geometric axis of the mandrel 20 and is preferably formed of, or has its top face 82U hardened with, a highly polished and wear resistant material, such as tungsten carbide or cemented carbide. An annular upper thrust bearing track 84, having a flat bottom face 84L, is fixed, by similar non-rotating means as previously described for the lower bearing track 82, to the lower end of an internally threaded ring 86, which has a surface flat top ring 86U and is screwed onto chuck 20 (as indicated by screw connection 85). The lower face 84L of the upper thrust bearing track 84 preferably has its face hardened like the upper face 82U of the lower bearing track 82, previously described.
    [00037] Figures 3A and 3B also illustrate the optional radial bearing unit 140, provided in conjunction with the thrust bearing unit outside the bottom 80. An internally threaded radial bearing support ring 110, having annular top and bottom surfaces flat 110U and 110L, is screwed coaxially into mandrel 20 (as indicated by threaded connection 111) over threaded ring 86, with the bottom surface 110L contacting the upper surface 86U of threaded ring 86 and with the upper surface 110U contacting the adjacency 93 of the drive shaft adapter 92. In the illustrated embodiment, the radial bearing unit 140 comprises an inner radial bearing track 142, coaxially and not rotatably mounted within housing 30. As best seen in Figure 3 A, the bearing track inner radial 142 has a cylindrical contact surface 142A and outer radial bearing raceway 144 has a cylindrical contact surface 144A. The contact surfaces 142A and 144A rotate in relation to each other and in union contact, when the mandrel 20 rotates in relation to the housing 30.
    [00038] The radial bearing rails 142 and 144 can be formed of or can have their respective contact surfaces 142A and 144A hardened on the faces with a highly polished and wear-resistant material, such as tungsten carbide or cemented carbide. Optionally, one or the other or both of the contact surfaces 142a and 144A can be provided with flow channels (not shown) to facilitate the flow of lubricating mud over the interface between the contact surfaces 142A and 144A. Although optional and not essential for the broader embodiments described here, the radial bearing unit 140 is advantageous for providing additional radial support for the upper end 20U of the mandrel 20 when it rotates within the housing 30.
    [00039] The operation of the bearing section 100 can be readily understood with reference to the Figures and the preceding description. In addition to being rotatable with respect to housing 30, mandrel 20 can also move axially with respect to housing 30 through a short travel range determined by the dimensions and positions of various components of the thrust bearing units off the bottom. More specifically, when the bearing section 100 is under load at the bottom, such as when the drill is under load at the bottom of a well hole, the mandrel 20 is moved slightly upwards into the housing 30, so that the bearing bottom thrust 60 and its associated tracks 61U and 61L are in compression between the load transfer shoulder 27 of the mandrel 20 and the load transfer shoulder 34 of the housing 30. Compressive bottom push loads are thus transferred from the mandrel 20 to housing 30 through thrust bearing 60.
    [00040] This upward displacement of the mandrel 20 inside the housing 30 has the effect of displacing the threaded ring 86 slightly upwards in relation to the housing 30, thus opening a gap between the lower face 84L of the bearing track 84 to the upper face 82U of the bearing track 82. However, when the compressive load on the bearing section 100 is released (by lifting the drill from the bottom of the well hole), the bearing section 100 will then be under thrust load off the bottom ( traction) and gravity and / or fluid pressure will cause the mandrel 20 to move axially downwardly relative to the housing 30, thereby bringing the lower face 84L of the bearing track 84 into tight contact with the upper face 82U of bearing track 82, as seen in Figure 3A. At the same time, the length of the lower bearing track 125 (that is, the distance between the load transfer lugs 27 and 34) will increase slightly, thereby unloading the thrust bearing 60. The thrust loads outside the bottom are thus resisted by contact between the surfaces 82U and 84L of the bearing tracks 82 and 84 of the thrust bearing unit outside the bottom 80.
    [00041] During operation of the mud motor, the drilling mud is pumped down through the annular crown of the shaft housing 97 and then directed into the central hole 22 of the mandrel 20, through the mud flow channels. 99 inside the drive shaft adapter 92. A small portion of the mud flow is diverted through the thrust bearing unit off the bottom 80, to provide lubrication and cooling to the thrust bearing unit 80 (and radial bearing unit 140 when included) before rejoining the main mud flow at the central hole 22. This is illustrated more specifically in Figure 3B, which shows a mud flow path 150 downstream of the drive shaft housing ring 97, through an annular space 95 between the driveshaft adapter 92 and the bearing section housing 30; then through the interface between the surfaces 142A and 144A of the radial bearing tracks 142 and 144, then down through the upper bearing track 81 and through the interface the lower face 84L of the upper thrust bearing track 84 and the face upper 82U of lower bearing track 82; and, finally, through one or more mud holes 155 through the mandrel wall 23 into the central hole 22. In this way, substantially all of the drilling mud is diverted through the upper bearing track 81 to lubricate and cool the cooling unit. bearing 80 will join the primary drilling fluid flow through central hole 22 to the drill.
    [00042] In an alternative embodiment not shown, where the bearing track 84 is not axially attached to the threaded ring 86, the fluid flow through the bearing unit will keep faces 82U and 84L together and one will open -it is between the bearing track 84 and the threaded ring 86, instead of between the bearing track 84 and the bearing track 82. However, the operation of the assembly will on the other hand be as described above.
    [00043] As previously noted, the radial bearing unit 140, shown in Figures 2, 3A and 3B, is optional. In an alternative embodiment, the threaded ring 86 and the radial bearing support ring 110 are combined to form a single piece. In a second alternative embodiment, the components of the thrust bearing unit outside the bottom 80 are essentially as described above and illustrated in Figures 2, 3A and 3B, except that the radial bearing support ring 110, radial bearing track inner 142 and outer radial support track 144 are eliminated. In this alternative embodiment, the upper surface 86U of the threaded ring 86 rests directly on the annular contiguity 93 of the drive shaft adapter 92, however the operation of the bearing section 100 under thrust load both on the bottom and outside the bottom is effectively the same as previously described here. In yet a third alternative embodiment, the threaded ring 86 is also eliminated and the upper thrust bearing track 84 is attached to the lower end of the drive shaft adapter 92.
    [00044] In the out-of-the-floor bearing unit lubricated with mud 80 shown in Figures 2, 3A and 3B, the load transfer surfaces (lower face 84L of bearing track 84 and upper face 82U of bearing track 82) are in direct contact when the bearing section 100 is operating out of the bottom, with the lower face 84L rotating in relation to the upper face 82U. However, this is just an example, other types of mud lubricated bearing units can be used, without deviating from the design and scope of the present description. For example, compact polycrystalline diamond (PDC) insert bearings of a type as available from US Synthetic Bearings of Orem, Utah, could be used in place of the illustrated unit, as could ceramic insert bearings of the type manufactured by Ceradyne, Inc. of Costa Mesa, California.
    [00045] Another alternative embodiment would use mud-lubricated roller bearings and raceways, such as mud-lubricated roller bearings available from QA Bearing Technologies Ltd. of Edmonton, Alberta and QA Bearing Technologies (USA) Inc. of Houston, Texas . While not providing as high static load capacities as are available with other types of mud lubricated bearings, these alternative bearings however would provide advantages over prior art bearing arrangements in that they do not require a high-tolerance slotted ring for provide load transfer lugs (as in the bearing section of the previous art in Figure 1).
    [00046] In alternative embodiments, the radial bearings 112 and 114 could be provided in the form of PDC insert bearings or ball bearings.
    [00047] In alternative embodiments the radial bearing unit 140 could be located under the thrust bearing unit outside the bottom lubricated with mud 80, instead of on top of it, as in the embodiment shown in Figures 2, 3A and 3B.
    [00048] Although the preferred embodiments have been shown and described, their modifications can be made by a person skilled in the art without deviating from the scope or teachings here. The embodiments described here are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus and processes described here are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials of which the various parts are made and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described here, but is only limited by the claims that follow, the scope of which will include all equivalents of the subject of the claims.
    权利要求:
    Claims (17)
    [0001]
    1. Bearing section (100) for a mud engine, which section has upper and lower ends and which comprises: an elongated mandrel (20), rotating and coaxially arranged inside an elongated cylindrical housing (30); the mandrel (20) having an upper end (20U), a lower end (20L), an outer surface (21) extending from the upper end (20U) to the lower end (20L), and a central hole (22) that extends from the upper end (20U) to the lower end (20L); a first annular bearing chamber (81) radially disposed between the mandrel (20) and the housing (30), the first bearing chamber (81) having a lower end defined by an annular adjacency (33) associated with the housing (30) ), and an upper end defined by a lower end of a cylindrical driveshaft adapter (92) which is attached to the upper end (20U) of the mandrel (20); a mud lubricated thrust bearing unit (80) disposed within the first bearing chamber (81) axially adjacent to that lower end of the first bearing chamber (81), wherein the mud lubricated thrust bearing unit (80) it is configured to support compression loads between that annular adjacency (33) and that transmission shaft adapter (92) when the bearing section (100) is under axial tension; and an annular space (97) between the driveshaft adapter (92) and the housing (30) which is in fluid communication with the first bearing chamber (81), and is configured to flow drilling fluid into the first chamber bearing (81); such a section characterized by further comprising: one or more holes (155) extending through the mandrel (20) from the first bearing chamber (81) to the central hole (22), in which that one or more holes (155) are configured to flow drilling fluid from the first bearing chamber (81) to the central hole (22).
    [0002]
    2. Bearing section (100) according to claim 1, characterized in that the mud lubricated thrust bearing unit (80) comprises: an upper bearing track (84), not rotatably fixed at the lower end the drive shaft adapter (92); and a lower bearing track (82), not rotatably fixed to the annular adjacency (33) associated with the housing (30).
    [0003]
    3. Bearing section (100), according to claim 2, characterized by the fact that: the upper bearing track (84) has a flat bottom face (84L) transversal to the geometric axis of the mandrel (20); and the lower bearing track (82) has a flat top face (82U) transverse to the geometric axis of the mandrel (20), said upper face (82U) being pluggable in union with that lower face (84L) of the upper bearing track ( 84).
    [0004]
    4. Bearing section (100) according to claim 3, characterized by the fact that the lower face (84L) of the upper bearing track (84) and the upper face (82U) of the lower bearing track (82) are hardened with a wear-resistant material.
    [0005]
    5. Bearing section (100), according to claim 4, characterized by the fact that such wear-resistant material comprises cemented carbide.
    [0006]
    6. Bearing section (100) according to claim 1, characterized in that such a mud lubricated thrust bearing unit (80) comprises compact polycrystalline diamond insert bearings.
    [0007]
    7. Bearing section (100) according to claim 1, characterized by the fact that such a mud lubricated thrust bearing unit (80) comprises ceramic insertion bearings.
    [0008]
    8. Bearing section (100) according to claim 1, characterized by the fact that such a mud lubricated thrust bearing unit (80) comprises roller bearings.
    [0009]
    9. Bearing section (100) according to claim 1, characterized in that it further comprises a radial bearing unit (140) disposed within the first bearing chamber (81).
    [0010]
    10. Bearing section (100) according to claim 9, characterized in that such a radial bearing unit (140) comprises: a radial bearing support ring (110) coaxially arranged around the mandrel ( 20); a cylindrical inner radial bearing track (142) having an outer cylindrical contact surface (142A), the inner radial bearing track (142) being coaxially arranged around the radial bearing support ring (110) and not rotationally fixed in him; a cylindrical outer radial bearing raceway (144) having an inner cylindrical contact surface (144A), the outer radial raceway raceway (144) being non-rotatably fixed in the housing (30) with that inner cylindrical contact surface (144A) in union with that external cylindrical contact surface (142A) of the inner radial bearing raceway (142).
    [0011]
    11. Bearing section (100) according to claim 9, characterized in that such radial bearing unit (140) comprises compact polycrystalline diamond insert bearings.
    [0012]
    12. Bearing section (100) according to claim 9, characterized by the fact that such a radial bearing unit (140) comprises ball bearings.
    [0013]
    13. Bearing section (100), according to claim 1, characterized by the fact that it further comprises: an annular oil reservoir that is radially disposed between the mandrel (20) and the housing (30), and which extends axially between an upper rotary seal (135) positioned between the mandrel (20) and the housing (30) and a lower rotary seal (115) positioned between the mandrel (20) and the housing (30), a portion of said oil reservoir defining a second annular bearing chamber (125), wherein that second bearing chamber (125) has a lower end limited by an annular lower shoulder (27) associated with said mandrel (20) and a limited upper end by an annular upper shoulder (34) associated with said housing (30); and a thrust bearing (60) disposed within the second bearing chamber (125), in which the thrust bearing (60) is configured to support compression loads between such upper (34) and lower (27) shoulders when the bearing section (100) is under axial compression.
    [0014]
    14. Bearing section (100), according to claim 9, characterized by the fact that it further comprises: an annular oil reservoir that is radially disposed between the mandrel (20) and the housing (30), and which extends axially between an upper rotary seal (135) positioned between the mandrel (20) and the housing (30) and a lower rotary seal (115) positioned between the mandrel (20) and the housing (30), a portion of said oil reservoir defining a second annular bearing chamber (125), wherein that second bearing chamber (125) has a lower end limited by an annular lower shoulder (27) associated with said mandrel (20) and a limited upper end by an annular upper shoulder (34) associated with said housing (30); and a thrust bearing (60) disposed within the second bearing chamber (125), in which the thrust bearing (60) is configured to support compression loads between such upper (34) and lower (27) shoulders when the bearing section (100) is under axial compression.
    [0015]
    15. Bearing section (100) for a mud engine, which section comprises: an elongated mandrel (20), rotating and coaxially arranged inside an elongated cylindrical housing (30); the mandrel (20) having an upper end (20U), a lower end (20L), an outer surface (21) extending from the upper end (20U) to the lower end (20L), and a central hole (22) that extends from the upper end (20U) to the lower end (20L); and the housing (30) with an internal surface (31); a first annular bearing chamber (81) which is arranged between the mandrel (20) and the housing (30), the first bearing chamber (81) having a lower end defined by an annular adjacency (33) associated with the housing ( 30), and an upper end defined by a lower end of a cylindrical driveshaft adapter (92) which is attached to the upper end (20U) of the mandrel (20); a mud lubricated thrust bearing unit (80) disposed within the first bearing chamber (81) axially adjacent to that lower end of the first bearing chamber (81), wherein the mud lubricated thrust bearing unit (80) it is configured to support compression loads between that annular adjacency (33) and that transmission shaft adapter (92) when the bearing section (100) is under axial tension; an annular oil reservoir which is laterally bounded by the mandrel (20) and the housing (30), and which extends between an upper rotating seal (135) positioned between the mandrel (20) and the housing (30) and a rotating seal lower (115) positioned between the mandrel (20) and the housing (30), a part of said oil reservoir defining a second annular bearing chamber (125), the second bearing chamber (125) having a limited lower end by an annular lower shoulder (27) associated with said mandrel (20) and an upper end limited by an annular upper shoulder (34) associated with said housing (30); a thrust bearing (60) disposed within the second bearing chamber (125), in which the thrust bearing (60) is configured to support compression loads between such upper (34) and lower (27) shoulders when the section bearing (100) is under axial compression; and an annular space (97) between the driveshaft adapter (92) and the housing (30) which is in fluid communication with the first bearing chamber (81), and is configured to flow drilling fluid into the first chamber bearing (81); such a section characterized by additionally comprising: one or more holes (155) extending through the mandrel (20) from the first bearing chamber (81) to the central hole (22), in which that one or more holes (155) are configured to flow drilling fluid from the first bearing chamber (81) to the central hole (22).
    [0016]
    16. Bearing section (100) according to claim 15, characterized in that it further comprises a radial bearing unit (140) disposed within the first bearing chamber (81).
    [0017]
    17. Bearing section (100) according to claim 16, characterized by the fact that such a radial bearing unit (140) comprises: a radial bearing support ring (110) coaxially arranged around the mandrel ( 20); a cylindrical inner radial bearing track (142) having an outer cylindrical contact surface (142A), the inner radial bearing track (142) being coaxially arranged around the radial bearing support ring (110) and not rotationally fixed in him; a cylindrical outer radial bearing raceway (144) having an inner cylindrical contact surface (144A), the outer radial raceway raceway (144) being non-rotatably fixed in the housing (30) with that inner cylindrical contact surface (144A) in joint fitting with that external cylindrical contact surface (142A) of the inner radial bearing raceway (142)
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    同族专利:
    公开号 | 公开日
    US8511906B2|2013-08-20|
    RU2559981C2|2015-08-20|
    WO2012103318A4|2013-05-23|
    WO2012103318A2|2012-08-02|
    WO2012103318A3|2013-03-14|
    CA2825027C|2016-05-03|
    RU2013135453A|2015-03-10|
    US20120195542A1|2012-08-02|
    BR112013019051A2|2017-02-21|
    CA2825027A1|2012-08-02|
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    法律状态:
    2018-12-18| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-10-22| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-06-02| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2020-09-15| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 26/01/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    US13/014819|2011-01-27|
    US13/014,819|US8511906B2|2011-01-27|2011-01-27|Oil-sealed mud motor bearing assembly with mud-lubricated off-bottom thrust bearing|
    PCT/US2012/022700|WO2012103318A2|2011-01-27|2012-01-26|Oil-sealed mud motor bearing assembly with mud-lubricated off-bottom thrust bearing|
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