CHIP DEFLECTOR ON A BLADE OF A DOWNHOLE REAMER AND METHODS THEREFORE
An expandable reamer apparatus for drilling a subterranean formation includes a tubular body, one or more blades, each blade positionally coupled to a sloped track of the tubular body having a hardfacing material on a portion thereof, a push sleeve and a drilling fluid flow path extending through an inner bore of the tubular body for conducting drilling fluid therethrough.
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This application is a utility conversion of U.S. Provisional Application Ser. No. 61/156,936, filed Mar. 3, 2009, for “CHIP DEFLECTOR ON A BLADE OF A DOWNHOLE REAMER AND METHODS THEREFOR,” the entire disclosure of which is hereby incorporated herein by this reference.
TECHNICAL FIELDThe present invention relates generally to improved blades for an expandable reamer apparatus for drilling a subterranean borehole and, more particularly, to improved blades for an expandable reamer apparatus for enlarging a subterranean borehole beneath a casing or liner.
BACKGROUNDExpandable reamers are typically employed for enlarging subterranean boreholes. Conventionally in drilling oil, gas, and geothermal wells, casing is installed and cemented to prevent the well bore walls from caving into the subterranean borehole while providing requisite shoring for subsequent drilling operations to achieve greater depths. Casing is also conventionally installed to isolate different formations, to prevent crossflow of formation fluids, and to enable control of formation fluids and pressure as the borehole is drilled. To increase the depth of a previously drilled borehole, new casing is laid within and extended below the previous casing. While adding additional casing allows a borehole to reach greater depths, it has the disadvantage of narrowing the borehole. Narrowing the borehole restricts the diameter of any subsequent sections of the well because the drill bit and any further casing must pass through the existing casing. As reductions in the borehole diameter are undesirable because they limit the production flow rate of oil and gas through the borehole, it is often desirable to enlarge a subterranean borehole to provide a larger borehole diameter for installing additional casing beyond previously installed casing as well as to enable better production flow rates of hydrocarbons through the borehole.
A variety of approaches have been employed for enlarging a borehole diameter. One conventional approach used to enlarge a subterranean borehole includes using eccentric and bi-center bits. For example, an eccentric bit with a laterally extended or enlarged cutting portion is rotated about its axis to produce an enlarged borehole diameter. An example of an eccentric bit is disclosed in U.S. Pat. No. 4,635,738, assigned to the assignee of the present invention. A bi-center bit assembly employs two longitudinally superimposed bit sections with laterally offset axes, which when rotated produce an enlarged borehole diameter. An example of a bi-center bit is disclosed in U.S. Pat. No. 5,957,223, which is also assigned to the assignee of the present invention.
Another conventional approach used to enlarge a subterranean borehole includes employing an extended bottomhole assembly with a pilot drill bit at the distal end thereof and a reamer assembly some distance above. This arrangement permits the use of any standard rotary drill bit type, be it a rock bit or a drag bit, as the pilot bit, and the extended nature of the assembly permits greater flexibility when passing through tight spots in the borehole as well as the opportunity to effectively stabilize the pilot drill bit so that the pilot hole and the following reamer will traverse the path intended for the borehole. This aspect of an extended bottomhole assembly is particularly significant in directional drilling. The assignee of the present invention has, to this end, designed as reaming structures so called “reamer wings,” which generally comprise a tubular body having a fishing neck with a threaded connection at the top thereof and a tong die surface at the bottom thereof, also with a threaded connection. U.S. Pat. Nos. 5,497,842 and 5,495,899, both assigned to the assignee of the present invention, disclose reaming structures including reamer wings. The upper midportion of the reamer wing tool includes one or more longitudinally extending blades projecting generally radially outwardly from the tubular body, the outer edges of the blades carrying PDC cutting elements.
As mentioned above, conventional expandable reamers may be used to enlarge a subterranean borehole and may include blades pivotably or hingedly affixed to a tubular body and actuated by way of a piston disposed therein as disclosed by U.S. Pat. No. 5,402,856 to Warren. In addition, U.S. Pat. No. 6,360,831 to Akesson et al. discloses a conventional borehole opener comprising a body equipped with at least two hole opening arms having cutting means that may be moved from a position of rest in the body to an active position by exposure to pressure of the drilling fluid flowing through the body. The blades in these reamers are initially retracted to permit the tool to be run through the borehole on a drill string and once the tool has passed beyond the end of the casing, the blades are extended so the bore diameter may be increased below the casing.
The blades of conventional expandable reamers have been sized to minimize a clearance between themselves and the tubular body in order to prevent any drilling mud and earth fragments from becoming lodged in the clearance and binding the blade against the tubular body. The blades of these conventional expandable reamers utilize pressure from inside the tool to apply force radially outward against pistons which move the blades, carrying cutting elements, laterally outward. It is felt by some that the nature of the conventional reamers allows misaligned forces to cock and jam the pistons and blades, preventing the springs from retracting the blades laterally inward. Also, designs of these conventional expandable reamer assemblies fail to help blade retraction when jammed and pulled upward against the borehole casing. Furthermore, some conventional hydraulically actuated reamers utilize expensive seals disposed around a very complex shaped and expensive piston, or blade, carrying cutting elements. In order to prevent cocking, some conventional reamers are designed having the piston shaped oddly in order to try to avoid the supposed cocking, requiring matching, complex seal configurations. These seals are feared to possibly leak after extended usage.
Hardfacing has been used in the downhole tool art for some time as a way to increase the erosion and abrasion resistance of certain areas of roller cone bits and steel body bits. Relatively thin layers of hardfacing have been applied to relatively large areas where erosion and abrasion from cuttings, high-velocity fluid and contact with the formation causes undesirable wear on the bit. Steel bits, such as roller cone bits, exhibit much more erosive and abrasive wear than so-called matrix bits which are manufactured by infiltration of molten metal into a matrix material comprising tungsten carbide or other powder. Many fixed cutter drill bits are manufactured from tungsten carbide matrix, as well as from steel. Steel body bits tend to exhibit superior toughness but limited erosion and abrasion resistance, whereas matrix bits tend to exhibit reduced toughness but exemplary erosion and abrasion resistance.
Hardfacing is generally composed of some form of hard particles delivered to a surface via a welding delivery system. Hardfacing refers to the deposited material rather than the constituent materials which make up the hardfacing. Constituent materials of hardfacing are referred to as a hardfacing composition. Hard particles may come from the following group of cast or sintered carbides consisting of chromium, molybdenum, niobium, tantalum, titanium, tungsten, and vanadium, and alloys and mixtures thereof, as disclosed by U.S. Pat. No. 5,663,512 to Schader et al., assigned to the assignee of the present invention and incorporated by reference herein. Commonly, a mixture of sintered, macrocrystalline, or cast tungsten carbides is captured within a mild steel tube. The steel tube containing the carbide mixture is then used as a welding rod to deposit hardfacing onto the desired surface, usually with a deoxidizer, or flux.
The shape, size, and relative percentage of different hard particles will affect the wear and toughness properties of the deposited hardfacing, as described by Schader et al. U.S. Pat. No. 5,492,186 to Overstreet, assigned to the assignee of the present invention and incorporated by reference herein, describes a hardfacing configuration for heel row teeth on a roller cone drill bit. The coating comprises two hardfacing compositions tailored for different properties. A first hardfacing composition may be characterized by good sliding wear resistance and/or abrasion resistance with a lower level of toughness. The second hardfacing composition contains carbide particles of spherical sintered, crushed sintered and cast tungsten carbide. A substantial portion of the particles in the second composition are characterized by a higher level of fracture resistance, or toughness, and a lower level of abrasion resistance.
Hardfacing compositions have been also used for coating the gage surfaces of roller cone teeth, as disclosed in U.S. Pat. No. 3,800,891 to White et al. White also discloses, with respect to the hardfacing of teeth on a milled steel tooth rolling cone-type bit, circumferential grooves and a transverse slot on each roller cone tooth for the deposition of hardfacing.
Hardfacing has been utilized with steel body bits in certain circumstances. For example, U.S. Pat. No. 4,499,958 to Radtke et al. discloses hardfacing on the blades and other portions of the bit subject to abrasive wear. However, use of hardfacing material as taught by Radtke et al. does not address issue of material toughness as may be required for various portions of the bit while also exploiting the advantages of an abrasion-resistant material.
So-called matrix bits, aforementioned for their superior abrasion and erosion resistance, have also been contemplated as benefitting from hardfacing as well. U.S. Pat. No. 4,884,477 to Smith et al., assigned to the assignee of the present invention, discloses a metal matrix bit body composed of a filler material of higher toughness than tungsten carbide with substantially all of the internal and external surfaces of the bit body coated with an erosion- and abrasion-resistant hardfacing comprised of tungsten carbide or silicon carbide. However, Smith et al. does not address strategic localization of a material according to its characteristics of either abrasion resistance or material toughness. Smith et al. fail to particularly address such issues with regard to a steel body bit.
Chip breakers serve to influence the formation of chips which are initiated at the leading edges of cutters and are pushed along the surface of a blade of the bit carrying the cutters such that they are weakened and subsequently broken into smaller elements during the drilling process. Such a chip breaker is described in greater detail in U.S. Pat. No. 5,582,258 to Tibbitts et al., assigned to the assignee of the present invention and incorporated by reference herein. Chip breakers form a “bump” in the surface of the blade and in the direct path of the formation of the chip which causes the chip to break before becoming overly elongated. This breakage prevents chips from building up along the surface of the bit and possibly balling the bit with an agglomeration of chips, as is known in the art. Chip breakers in steel body bits may be machined into the surface of the bit; however, this too may place limits on the bit design.
Gage elements for steel body bits are typically formed by drilling holes into the gage surface and pressing sintered tungsten carbide cylinders into the holes. As an additional measure, a layer of hardfacing may be applied around the sintered carbide cylinders, on the body of the bit, but the cylinders function as the main elements to prevent abrasion and wear on the gage, and are designed and configured to maximize the exposed area of the sintered cylinders to the borehole sidewall. Although sintered carbide cylinders function adequately as a drill bit gage, the necessity of milling precise holes for press fitting is cumbersome and limits the configuration of the gage. In addition, sintered carbide gage cylinders often exhibit cracking after use, referred to as crazing, perhaps attributable to the extreme heating and cooling cycles present during drilling conditions.
Notwithstanding the various prior approaches to drill and/or ream a larger diameter borehole below a smaller diameter borehole, the need exists for improved apparatus and methods for doing so. In view of the shortcomings in the art, it would be advantageous to provide an expandable reamer employing structural blades having hardfacing materials on portions thereof.
Accordingly, there is an ongoing desire to improve or extend performance of an expandable reamer apparatus regardless of the subterranean formation type being drilled. There is a further desire to provide a reamer apparatus that provides fail-safe blade retraction, is robustly designed with conventional seal or sleeve configurations, and may not require sensitive tolerances between moving parts.
BRIEF SUMMARY OF THE INVENTIONAn expandable reamer apparatus for drilling a subterranean formation including a tubular body, one or more blades positionally coupled to the track of the tubular body, a push sleeve and a drilling fluid flow path extending through the tubular body for conducting drilling fluid therethrough are disclosed. The tubular body includes a longitudinal axis, an inner bore, an outer surface, and at least one track communicating through the tubular body between the inner bore and the outer surface, the track exhibiting a slope at an acute angle to the longitudinal axis. The one or more blades each include hardfacing thereon and least one cutting element configured and oriented to remove material from the wall of a borehole of a subterranean formation to enlarge the borehole diameter responsive to rotation of the apparatus. The push sleeve is positionally coupled to the inner bore of the tubular body and coupled to at least one blade so as to be configured to selectively allow communication of drilling fluid passing through the tubular body to effect axial movement thereof responsive to a force or pressure of drilling fluid so as to transition the at least one blade along the track from a retracted position into an extended position for reaming.
While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as the invention, various features and advantages of this invention may be more readily ascertained from the following description of the invention when read in conjunction with the accompanying drawings, in which:
The illustrations presented herein are, in some instances, not actual views of any particular reamer tool, cutting element, or other feature of a reamer tool, but are merely idealized representations that are employed to describe the present invention. Additionally, elements common between figures may retain the same numerical designation.
An expandable reamer apparatus 100 according to an embodiment of the invention is shown in
Three sliding cutter blocks or blades 101, 102, 103 (see
Referring to
The expandable reamer apparatus 100 includes a shear assembly 150 for retaining the expandable reamer apparatus 100 in the initial position by securing the traveling sleeve 128 toward the upper end 191 thereof. Reference may also be made to
With reference to
Shock absorbing member 125 may comprise a flexible or compliant material, such as, for instance, an elastomer or other polymer. In one embodiment, shock absorbing member 125 may comprise a nitrile rubber. Utilizing a shock absorbing member 125 between the traveling sleeve 128 and seal sleeve 126 may reduce or prevent deformation of at least one of the traveling sleeve 128 and seal sleeve 126 that may otherwise occur due to impact therebetween.
It should be noted that any sealing elements or shock absorbing members disclosed herein that are included within expandable reamer apparatus 100 may comprise any suitable material as known in the art, such as, for instance, a polymer or elastomer. Optionally, a material comprising a sealing element may be selected for relatively high temperature (e.g., about 400° Fahrenheit or greater) use. For instance, seals may be comprised of TEFLON®, polyetheretherketone (“PEEK™”) material, a polymer material, or an elastomer, or may comprise a metal-to-metal seal suitable for expected borehole conditions. Specifically, any sealing element or shock absorbing member disclosed herein, such as shock absorbing member 125 and sealing elements, such as O-ring seals 134 and 135, discussed hereinabove, or sealing elements, such as T-seal seal 137, discussed herein below, or other sealing elements included by an expandable reamer apparatus of the invention may comprise a material configured for relatively high temperature use, as well as for use in highly corrosive borehole environments.
The seal sleeve 126 includes an O-ring seal 136 sealing it between the inner bore 151 of the tubular body 108, and a T-seal seal 137 sealing it between the outer bore 162 of the traveling sleeve 128, which completes fluid sealing between the traveling sleeve 128 and the nozzle intake port 164. Furthermore, the seal sleeve 126 axially aligns, guides and supports the traveling sleeve 128 within the tubular body 108. Moreover, the O-ring seal 136 and T-seal seal 137, respectively, may also prevent hydraulic fluid from leaking from within the expandable reamer apparatus 100 to outside the expandable reamer apparatus 100 by way of the nozzle intake port 164 prior to the traveling sleeve 128 being released from its initial position.
A downhole end 165 of the traveling sleeve 128 (also see
The dogs 166 are positionally retained between an annular groove 167 in the inner bore 151 of the tubular body 108 and the seat stop sleeve 130. Each dog 166 of the lowlock sleeve 117 is a collet or locking dog latch having an expandable detent 168 that may engage the annular groove 167 of the tubular body 108 when compressively engaged by the seat stop sleeve 130. The dogs 166 hold the lowlock sleeve 117 in place and prevent the push sleeve 115 from moving in the uphole direction 159 until the “end” or seat stop sleeve 130, with its larger outer diameter 169, travels beyond the lowlock sleeve 117 allowing the dogs 166 to retract axially inward toward the smaller outer diameter 170 of the traveling sleeve 128. When the dogs 166 retract axially inward they may be disengaged from the annular groove 167 of the tubular body 108, allowing the push sleeve 115 to be subjected to hydraulic pressure primarily in the axial direction, i.e., in the uphole direction 159.
The shear assembly 150 requires an affirmative act, such as introducing a ball or other restriction element into the expandable reamer apparatus 100 to cause the pressure from hydraulic fluid flow to increase, before the shear screws 127 will shear.
The downhole end 165 of the traveling sleeve 128 includes within its inner bore a ball trap sleeve 129 that includes a plug 131. An O-ring seal 139 may also provide a seal between the ball trap sleeve 129 and the plug 131. A restriction element in the form of a ball 147 (
Optionally, the ball 147 used to activate the expandable reamer apparatus 100 may engage the ball trap sleeve 129 and the plug 131 that include malleable characteristics, such that the ball 147 may swage therein as it seats in order to prevent the ball 147 from moving around and potentially causing problems or damage to the expandable reamer apparatus 100.
Also, in order to support the traveling sleeve 128 and mitigate vibration effects after the traveling sleeve 128 is axially retained, the seat stop sleeve 130 and the downhole end 165 of the traveling sleeve 128 are retained in a stabilizer sleeve 122. Reference may also be made to
After the traveling sleeve 128 travels sufficiently far enough to allow the dogs 166 of the lowlock sleeve 117 to be disengaged from the annular groove 167 of the tubular body 108, the dogs 166 of the lowlock sleeve 117, being connected to the push sleeve 115, may all move in the uphole direction 159. Reference may also be made to
The push sleeve 115 includes at its uphole section 176, a yoke 114 coupled thereto as shown in
In order that the blades 101, 102, 103 may transition between the extended and retracted positions, they are each positionally coupled to one of the blade tracks 148 in the tubular body 108 as particularly shown in
As previously stated, the blades 101, 102, 103 may be comprised of steel, tungsten carbide, a particle-matrix composite material (e.g., hard particles dispersed throughout a metal matrix material), or other suitable materials as known in the art. A blade 101, 102, 103 comprises a blade body including a plurality of primary cutter pockets 185 and secondary cutter pockets 186 located behind the primary cutter pockets 185, although the secondary cutter pockets 186 may be located within the kerf of a primary cutter pocket 185 but displaced from the centerline thereof. Additionally, although blades 101, 102, 103 have a primary cutter pockets 185 and secondary cutter pockets 186 therein, additional cutter pockets and cutting elements may be used on the blades as well as wear knots, and the like. Each of the primary cutter pockets 185 and secondary cutter pockets 186 have a cutting element 104 located therein. Each blade 101, 102, 103 includes a gage portion 101′ (see
Illustrated in
The blade track 148 includes a dovetail-shaped groove 179 (
Advantageously, the natural, reactive forces acting on the cutting elements 104 on the blades 101, 102, 103 during rotation of expandable reamer apparatus 100 in engaging a formation while reaming a borehole may help to further push the blades 101, 102, 103 in the extended outward direction, holding them with this force in their fully outward or extended position. Drilling forces acting on the cutting elements 104, therefore, along with higher pressure within expandable reamer apparatus 100 creating a pressure differential with that of the borehole exterior to the tool, help to further hold the blades 101, 102, 103 in the extended or outward position. Also, as the expandable reamer apparatus 100 is drilling, the fluid pressure may be reduced when the combination of the slanted slope 180 of the blade tracks 148 is sufficiently shallow, allowing the reactive forces acting on the cutting elements 104 to offset the biasing effect of the biasing spring 116. In this regard, application of hydraulic fluid pressure may be substantially minimized, while drilling as a mechanical advantage allows the reactive forces acting on the cutting elements 104 when coupled with the substantially shallower slanted slope 180 of the blade tracks 148 to provide the requisite reaction force for retaining the blades 101, 102, 103 in their extended position. Conventional reamers having blades extending substantially laterally outward from an extent of 35 degrees or greater (referenced to the longitudinal axis) requires the full, and continued, application of hydraulic pressure to maintain the blades in an extended position. Accordingly and unlike the case with conventional expandable reamers, the blades 101, 102, 103 of expandable reamer apparatus 100 have a tendency to open as opposed to tending to close when reaming a borehole. The direction of the net cutting force and, thus, of the reactive force may be adjusted by altering the backrake, exposure and siderake of the cutting elements 104 to better achieve a net force tending to move the blades 101, 102, 103 to their fullest outward extent.
Another advantage of a so-called “shallow track,” i.e., the substantially small slanted slope 180 having an acute angle, is greater spring force retraction efficiency. Improved retraction efficiency enables improved or customized spring rates to be utilized to control the extent of the biasing force by the spring 116, such as selecting the biasing force required to be overcome by hydraulic pressure to begin to move or fully extend the blades 101, 102, 103. Also, with improved retraction efficiency greater assurance of blade retraction is assured when the hydraulic fluid pressure is removed the expandable reamer apparatus 100. Optionally, the spring 116 may be preloaded when the expandable reamer apparatus 100 is in the initial or retracted positions, allowing a minimal amount of retraction force to be constantly applied.
Another advantage provided by the blade tracks 148 is the unitary design of each “dovetail-shaped” groove 179, there being one groove 179 for receiving one of the oppositely opposed “dovetail-shaped” rails 181 of the guides 187 on each side of the blades 101, 102, 103. In conventional expandable reamers, each side of a movable blade includes a plurality of ribs or channels for being received into opposing channels or ribs of the reamer body, respectively, such arrangements being highly prone to binding when the blades are subjected to operational forces and pressures. In addition to ease of blade extension and retraction without binding along or in the blade track 148, the single rail and cooperating groove design provides non-binding structural support for blade operation, particularly when engaging a formation while reaming.
In addition to the upper stabilizer block 105, the expandable reamer apparatus 100 also includes a mid stabilizer block 106 and a lower stabilizer block 107 (see
Advantageously, the upper stabilizer block 105 may be mounted, removed and/or replaced by a technician, particularly in the field, allowing the extent to which the blades 101, 102, 103 engage the borehole to be readily increased or decreased to a different extent than illustrated. Optionally, it is recognized that a stop associated on a track side of the upper stabilizer block 105 may be customized in order to arrest the extent to which the blades 101, 102, 103 may laterally extend when fully positioned to the extended position along the blade tracks 148. The stabilizer blocks 105, 106, 107 may include hardfaced bearing pads (not shown) to provide a surface for contacting a wall of a borehole while stabilizing the apparatus therein during a drilling operation.
Also, the expandable reamer apparatus 100 may include tungsten carbide nozzles 110 as shown in
The expandable reaming apparatus, or reamer, 100 is now described in terms of its operational aspects. Reference may be made to
Referring to
Thereafter, as illustrated in
As shown in
As reaming takes place with the expandable reamer apparatus 100, the hardfaced pads on the lower and mid stabilizer blocks 106, 107 help to stabilize the tubular body 108 as the cutting elements 104 of the blades 101, 102, 103 ream a larger borehole and the hardfaced pads on the upper stabilizer block 105 also help to stabilize the top of the expandable reamer apparatus 100 when the blades 101, 102 and 103 are in the retracted position.
After the traveling sleeve 128 with the ball 147 moves downward, it comes to a stop with the flow bypass or fluid ports 173 located above the ball 147 in the traveling sleeve 128 exiting against the inside wall 184 of the hardfaced protect sleeve 121, which helps to prevent or minimize erosion damage from drilling fluid flow impinging thereupon. The drilling fluid flow may then continue down the bottomhole assembly, and the upper end of the traveling sleeve 128 becomes “trapped,” i.e., locked, between the one or more ears 163 of the uplock sleeve 124 and the shock absorbing member 125 of the seal sleeve 126, and the lower end of the traveling sleeve 128 is laterally stabilized by the stabilizer sleeve 122.
When drilling fluid pressure is released, the spring 116 will help drive the lowlock sleeve 117 and the push sleeve 115 with the attached blades 101, 102, 103 back downwardly and inwardly substantially to their original or initial position into the retracted position, see
Whenever drilling fluid flow is re-established in the drill pipe and through the expandable reamer apparatus 100, the push sleeve 115, with the yoke 114 and blades 101, 102, 103, may move upward with the blades 101, 102, 103 following the ramps or blade tracks 148 to again cut/ream the prescribed larger diameter in a borehole. Whenever drilling fluid flow is stopped, i.e., the differential pressure falls below the restoring force of the spring 116, the blades 101, 102, 103 retract, as described above, via the spring 116.
In aspects of the invention, the expandable reamer apparatus 100 overcomes disadvantages of conventional reamers. For example, one conventional hydraulic reamer utilized pressure from inside the tool to apply force against cutter pistons which moved radially outward. It is felt by some that the nature of the conventional reamer allowed misaligned forces to cock and jam the pistons, preventing the springs from retracting them. By providing the expandable reamer apparatus 100, which slides each of the blades up a relatively shallow-angled ramp, higher drilling forces may be used to open and extend the blades to their maximum position while transferring the forces through to the upper hardface pad stop with no damage thereto and subsequently allowing the spring to retract the blades thereafter without jamming or cocking.
The expandable reamer apparatus 100 includes blades that, if not retracted by the spring, will be pushed down the ramp of the track by contact with the borehole wall and the casing and allow the expandable reamer apparatus 100 to be pulled through the casing, providing a kind of fail-safe function.
The expandable reamer apparatus 100 is not sealed around the blades 101, 102, 103 and does not require seals thereon, such as the expensive or custom made seals used in some conventional expandable reamers.
The expandable reamer apparatus 100 includes clearances of ranging from 0.010 of an inch to 0.030 of an inch between adjacent parts having dynamic seals therebetween. The dynamic seals are all conventional, circular seals. Moreover, the sliding mechanism or actuating means, which includes the blades in the tracks, includes clearances ranging from 0.050 of an inch to 0.100 of an inch, particularly about the dovetail portions. Clearances in the expandable reamer apparatus 100, the blades 101, 102, 103 and the blade tracks 148 may vary to a somewhat greater extent or a lesser extent than indicated herein. The larger clearances and tolerances of the parts of expandable reamer apparatus 100 promote ease of operation, particularly with a reduced likelihood of binding caused by particulates in the drilling fluid and formation debris cut from the borehole wall.
Additional aspects of the expandable reamer apparatus 100 are now provided:
The blade 101 may be held in place along the blade track 148 (shown in
The blades 101, 102, 103 are attached to a yoke 114 with the linkage assembly, as described herein, which allow the blades 101, 102, 103 to move upward and radially outward along the 5° to 25° (degree) ramp, in this embodiment of the invention, as the actuating means, i.e., the yoke 114 and push sleeve 115, moves axially upward. The link of the linkage assembly is pinned to both the blades 101, 102, 103 and the yoke 114 in a similar fashion. The linkage assembly, in addition to allowing the actuating means to directly extend and retract the blades 101, 102, 103 substantially in the longitudinal or axial direction, enables the upward and radially outward extension of the blades 101, 102, 103 by rotating through an angle, approximately 30-60 degrees in this embodiment of the invention, during the direct actuation of the actuating means and the blades 101, 102, 103.
In case the blades 101, 102, 103 somehow do not readily move back down the ramp of the blade tracks 148 under biasing force from the retraction spring 116, then as the expandable reamer apparatus 100 is pulled from the borehole, contact with the borehole wall will bump the blades 101, 102, 103 down the slanted slope 180 of the blade tracks 148. If needed, the blades 101, 102, 103 of the expandable reamer apparatus 100 may be pulled up against the casing, which may push the blades 101, 102, 103 further back into the retracted position thereby allowing access and removal of the expandable reamer apparatus 100 through the casing.
In other embodiments of the invention, the traveling sleeve 128 may be sealed to prevent fluid flow from exiting the tool through the blade passage ports 182 (
The nozzles 110, as mentioned above, may be directed in the direction of flow through the expandable reamer apparatus 100 from within the tubular body 108 downward and outward radially to the annulus between tubular body 108 and a borehole. Directing the nozzles 110 in such a downward direction causes counterflow as the flow exits the nozzle 110 and mixes with the annular moving counter flow returning up the borehole and may improve blade cleaning and cuttings removal. The nozzles 110 are directed at the cutting elements 104 of the blades 101, 102, 103 for maximum cleaning, and may be directionally optimized using computational fluid dynamics (“CFD”) analysis.
The expandable reamer apparatus 100 may include a lower saver sub 109 shown in
Still other aspects of the expandable reamer apparatus 100 are now provided:
The shear screws 127 of the shear assembly 150, retaining the traveling sleeve 128 and the uplock sleeve 124 in the initial position, are used to provide or create a trigger, releasing when pressure builds to a predetermined value. The predetermined value at which the shear screws 127 shear under drilling fluid pressure within expandable reamer apparatus 100 may be 1000 psi, for example, or even 2000 psi. It is recognized that the pressure may range to a greater or lesser extent than presented herein to trigger the expandable reamer apparatus 100. Optionally, it is recognized that a greater pressure at which the shear screws 127 shear may be provided to allow the spring 116 to be conditionally configured and biased to a greater extent in order to further provide desired assurance of blade retraction upon release of hydraulic fluid.
Optionally, one or more of the blades 101, 102, 103 may be replaced with stabilizer blocks having guides and rails as described herein for being received into dovetail-shaped grooves 179 of the blade track 148 in the expandable reamer apparatus 100, which may be used as an expandable concentric stabilizer rather than a reamer, which may further be utilized in a drill string with other concentric reamers or eccentric reamers.
Optionally, the blades 101, 102, 103 may each include one row or three or more rows of cutting elements 104 rather than the two rows of cutting elements 104 shown in
The measurement device 20 may be part of a nuclear based measurement system such as disclosed in U.S. Pat. No. 5,175,429 to Hall et al., the disclosure of which is fully incorporated herein by reference, and is assigned to the assignee of the invention herein disclosed. The measurement device 20 may also include sonic calipers, proximity sensors, or other sensors suitable for determining a distance between a wall of a borehole and the expandable reamer apparatus 10. Optionally, the measurement device 20 may be configured, mounted and used to determine the position of the movable blades and/or bearing pads of the expandable reamer apparatus 20, wherein the reamed minimum borehole diameter may be inferred from such measurements. Similarly, a measurement device may be positioned within the movable blade so as to be in contact with or proximate to the formation on the borehole wall when the movable blade is actuated to its outermost fullest extent.
As shown in
While the motion limiting members 210 and 220 (shown in
In other embodiments, the motion limiting members 210 or 220 may be simple structures for limiting the extent to which the actuating means may extend to limit the motion of the blades. For example, a motion limiting member may be a cylinder that floats within the space between the outer surface of the push sleeve 115 and the inner bore 151 of the tubular body 108, either between the spring 116 and the push sleeve 115 or the spring 116 and the tubular body 108.
The expandable reamer apparatus 100, as described above with reference to
In another aspect of the invention, the expandable reamer apparatus 100 drives the actuating means, i.e., the push sleeve 115, axially in a first direction while forcing the blades 101, 102, 103 to move to the extended position (the blades being directly coupled to the push sleeve 115 by a yoke 114 and linkage assembly). In the opposite direction, the push sleeve 115 directly retracts the blades 101, 102, 103 by pulling, via the yoke 114 and linkage assembly. Thus, activation means provides for the direct extension and retraction of the blades 101, 102, 103, irrespective of the biasing spring 116 or the hydraulic fluid as conventionally provided.
While particular embodiments of the invention have been shown and described, numerous variations and other embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention only be limited in terms of the appended claims and their legal equivalents.
Claims
1. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising:
- a tubular body having a longitudinal axis, an inner bore, an outer surface, and at least one track within the tubular body between the inner bore and the outer surface, the track sloped upwardly and outwardly at an acute angle to the longitudinal axis;
- a drilling fluid flow path extending through the inner bore;
- one or more blades each having at least one cutting element configured to remove material from a subterranean formation during reaming, at least one blade slidably coupled to the at least one track of the tubular body, the at least one blade having hardfacing material thereon; and
- a push sleeve disposed within the inner bore of the tubular body and coupled to the at least one blade, the push sleeve configured to move axially upward responsive to a pressure of drilling fluid passing through the drilling fluid flow path to extend the at least one blade along the at least one track and into an extended position.
2. The expandable reamer apparatus of claim 1, wherein at least one blade has a front surface having hardfacing material thereon.
3. The expandable reamer apparatus of claim 2, wherein the hardfacing material comprising a material having one of a curved surface, a substantially square cross-section, a substantially convex surface, and having two substantially convex surfaces.
4. The expandable reamer apparatus of claim 2, wherein at least one of the blades comprises a blade having a gage portion having hardfacing material located on a portion thereof.
5. The expandable reamer apparatus of claim 2, wherein at least one of the blades comprises a blade having a front surface having a channel located in a portion thereof, a portion of the channel containing hardfacing material therein.
6. The expandable reamer apparatus of claim 1, wherein at least one of the blades comprises a blade having an upper surface having at least one channel therein, at least a portion of at least one channel containing hardfacing material therein.
7. The expandable reamer apparatus of claim 1, further comprising a biasing element disposed within the inner bore of the tubular body, in contact with the push sleeve and oriented to bias the push sleeve in an axial downward direction to retract the at least one blade along the at least one track and into a retracted position when the push sleeve is not subjected to force or pressure of drilling fluid.
8. The expandable reamer apparatus of claim 1, wherein the at least one blade is directly coupled to the push sleeve by a linkage assembly.
9. The expandable reamer apparatus of claim 1, further including a guide structure for positionally retaining and guiding the at least one blade within the at least one track.
10. The expandable reamer apparatus of claim 1, further comprising a motion limiting member coupled between the tubular body and the push sleeve to limit the axial extent of the push sleeve.
11. The expandable reamer apparatus of claim 10, further comprising a traveling sleeve positioned within the inner bore of the tubular body and configured to selectively isolate the push sleeve and blades from exposure to force or pressure of drilling fluid, the traveling sleeve axially retained in an initial position by a shear assembly within the inner bore of the tubular body.
12. The expandable reamer apparatus of claim 11, wherein the push sleeve is axially retained in an initial position by a lowlock assembly coupled within the tubular body and comprising a lower end of the traveling sleeve, and the push sleeve is axially transitionable between the extended position and a retracted position after the traveling sleeve has axially transitioned sufficiently to release the push sleeve from the lowlock assembly.
13. The expandable reamer apparatus of claim 12, further comprising an uplock sleeve for axially retaining the traveling sleeve upon sufficient travel within the tubular body and upon exposing the push sleeve to exposure of force or pressure of drilling fluid within the flow path.
14. The expandable reamer apparatus of claim 1, further comprising a measurement device for determining a diameter of the enlarged borehole.
15. The expandable reamer apparatus of claim 12, further comprising a stabilizer sleeve coupled to the inner bore of a lower end of the tubular body for receiving a lower end of the traveling sleeve.
16. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising:
- a tubular body having a longitudinal axis, an inner bore, an outer surface, a plurality of upwardly and outwardly sloping tracks within the tubular body between the inner bore and the outer surface at an acute angle to the longitudinal axis;
- a drilling fluid flow path extending through the tubular body for conducting drilling fluid therethrough;
- a plurality of circumferentially spaced, generally radially and longitudinally extending blades, each blade slidably engaged with one of the plurality of tracks, carrying at least one cutting structure thereon and movable along its associated track between an extended position and a retracted position, each blade having hardfacing material thereon; and
- actuation structure positioned within the tubular body and configured to directly effect movement of the blades in the tracks in opposing directions responsive to a pressure of drilling fluid within the flow path and an opposing force.
17. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising:
- a tubular body having a longitudinal axis, an outer surface, and a track within the tubular body, the track sloped upwardly and outwardly at an acute angle to the longitudinal axis;
- a drilling fluid flow path extending through an inner bore of the tubular body;
- a blade having at least one cutting element configured to remove material from a subterranean formation during reaming and slidably coupled to the track, the blade having hardfacing material on a portion thereof;
- a push sleeve disposed within the inner bore of the tubular body and directly coupled to the blade, the push sleeve configured to move axially upward responsive to a pressure of drilling fluid passing through the inner bore to extend the blade along the track; and
- a traveling sleeve coupled to an inner bore of the push sleeve and configured to selectively allow communication of drilling fluid passing through the inner bore with the push sleeve to effect axial movement thereof and to secure the push sleeve in an initial position prior to movement thereof.
18. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising:
- a tubular body having a longitudinal axis and at least one track within a wall of the tubular body sloped upwardly and outwardly at an acute angle to the longitudinal axis;
- a drilling fluid flow path extending through an inner bore of the tubular body;
- at least one blade having at least one cutting element configured to remove material from a subterranean formation during reaming, the at least one blade slidably coupled to the at least one track, the at least one blade having hardfacing material on a portion thereof;
- a push sleeve disposed within the inner bore of the tubular body and directly coupled to the at least one blade, the push sleeve configured to move axially upward responsive to a pressure of drilling fluid passing through the inner bore to extend the at least one blade along the track;
- a longitudinal biasing element disposed within the inner bore of the tubular body and in contact with the push sleeve; and
- a motion limiting member coupled between the tubular body and the push sleeve to limit an extent of axial movement of the push sleeve responsive to the pressure.
19. An expandable reamer apparatus for enlarging a borehole in a subterranean formation, comprising:
- a body having a longitudinal axis;
- a drilling fluid flow path extending through the body for conducting drilling fluid therethrough;
- a plurality of blades carried by the body at an acute angle relative to the longitudinal axis, each blade carrying at least one cutting structure thereon, at least one blade having hardfacing material on a portion thereof; and
- an actuation means positioned within the body and configured to directly actuate the plurality of blades between an extended position and a retracted position in respective response to a pressure provided by the drilling fluid within the flow path and an opposing force.
20. A method of activating a downhole apparatus within a borehole of a subterranean formation, comprising:
- disposing a downhole apparatus within the subterranean formation having a plurality of blades, at least one blade having hardfacing material on a portion thereof, the downhole apparatus including a restriction element trap configured for retentively receiving a restriction element and positioned within a bore of an actuation element, positioned for movement within a bore of the downhole apparatus and configured to selectively isolate an operable component from drilling fluid pressure within the downhole apparatus prior to the movement;
- flowing drilling fluid through the downhole apparatus via a flow path;
- disposing a restriction element into the drilling fluid;
- receiving the restriction element in the restriction element trap carried by flowing drilling fluid through the flow path to occlude the flow path;
- releasing the actuation element for movement during or after occlusion of the fluid flow path; and
- effecting movement of the blades responsive to a pressure of drilling fluid within the flow path causing the plurality of blades to move outwardly in the borehole for the hardfacing material reducing wear of the at least one blade during operation of the downhole apparatus.
21. The method of claim 20, wherein receiving the restriction element in the restriction element trap is effected at a drilling fluid pressure substantially lower than a drilling fluid pressure required for releasing the actuation element.
22. A method of engaging a borehole of a subterranean formation using a downhole apparatus, comprising:
- disposing a downhole apparatus within the subterranean formation having a plurality of blades, at least one blade having a cutting element thereon for engaging the borehole and chip breaking material on a portion thereof for deflecting material from the borehole removed by the cutting element;
- flowing drilling fluid through the downhole apparatus via a flow path;
- effecting movement of the blades responsive to a pressure of drilling fluid within the flow path causing the plurality of blades to move outwardly in the borehole for the cutting element to engage the borehole;
- rotating the downhole apparatus for the cutting element to remove a portion of the subterranean formation; and
- deflecting from the at least one blade at least a portion of the portion of subterranean formation removed by the cutting element using the chip breaking material on the at least one blade.
23. A method of reducing wear on a blade of a downhole apparatus from the cuttings of a subterranean formation comprising:
- disposing a downhole apparatus within the subterranean formation having a plurality of blades, at least one blade having a cutting element thereon for engaging the borehole and chip breaking material on a portion thereof for deflecting material from the borehole removed by the cutting element;
- effecting movement of the blades outwardly in the borehole for the cutting element to engage the borehole;
- rotating the downhole apparatus for the cutting element to remove a portion of the subterranean formation; and
- deflecting at least a portion of the subterranean formation removed by the cutting element using the chip breaking material on the at least one blade.
Type: Application
Filed: Mar 2, 2010
Publication Date: Sep 9, 2010
Applicant: BAKER HUGHES INCORPORATED (Houston, TX)
Inventors: Steven R. Radford (The Woodlands, TX), Kevin G. Kidder (Carencro, LA)
Application Number: 12/715,610
International Classification: E21B 7/00 (20060101); E21B 10/26 (20060101);