Patent Application
20130087386
The invention, in various embodiments, relates generally to an expandable reamer apparatus for drilling a subterranean borehole and, more specifically, to enlarging a subterranean borehole beneath a casing or liner. The expandable reamer may comprise a tubular body configured with movable blades that may be directly radially or laterally displaced, the movable blades having cutting elements attached thereto.
State of the Art: Drill bits for drilling oil, gas, and geothermal wells, and other similar uses typically comprise a solid metal or composite matrix-type metal body having a lower cutting face region and an upper shank region for connection to the bottom hole assembly of a drill string formed of conventional jointed tubular members which are then rotated as a single unit by a rotary table or top drive drilling rig, or by a downhole motor selectively in combination with the surface equipment. Alternatively, rotary drill bits may be attached to a bottom hole assembly, including a downhole motor assembly, which is in turn connected to an essentially continuous tubing, also referred to as coiled, or reeled, tubing, wherein the downhole motor assembly rotates the drill bit. The bit body may have one or more internal passages for introducing drilling fluid, or mud, to the cutting face of the drill bit to cool cutters provided thereon and to facilitate formation chip and formation fines removal. The sides of the drill bit typically may include a plurality of radially or laterally extending blades that have an outermost surface of a substantially constant diameter and generally parallel to the central longitudinal axis of the drill bit, commonly known as gage pads. The gage pads generally contact the wall of the borehole being drilled in order to support and provide guidance to the drill bit as it advances along a desired cutting path, or trajectory.
As known within the art, blades provided on a rotary drill bit may be selected to be provided with replaceable cutting elements installed thereon, allowing the cutting elements to engage the formation being drilled and to assist in providing cutting action therealong. Replaceable cutters may also be placed adjacent to the gage area of the rotary drill bit and sometimes on the gage thereof. One type of cutting element, referred to as inserts, compacts, and cutters, has been known and used for providing the primary cutting action of rotary drill bits and drilling tools. These cutting elements are typically manufactured by forming a superabrasive layer, or table, upon a sintered tungsten carbide substrate. As an example, a tungsten carbide substrate having a polycrystalline diamond table or cutting face is sintered onto the substrate under high pressure and temperature, typically about 1450° C. to about 1600° C. and about 50 kilobar to about 70 kilobar pressure, to form a PDC cutting element or PDC cutter. During this process, a metal sintering aid or catalyst, such as cobalt, may be premixed with the powdered diamond or swept from the substrate into the diamond to form a bonding matrix at the interface between the diamond and substrate.
Further, in one conventional approach to enlarge a subterranean borehole, it is known to employ both eccentric and bi-center bits to enlarge a borehole below a tight or undersized portion thereof. For example, an eccentric bit includes an extended or enlarged cutting portion which, when the bit is rotated about its axis, produces an enlarged borehole. An example of an eccentric bit is disclosed in U.S. Pat. No. 4,635,738, assigned to the assignee of the present invention. Similarly, a bi-center bit assembly employs two longitudinally superimposed bit sections with laterally offset axes. An example of an exemplary bi-center bit is disclosed in U.S. Pat. No. 5,957,223, also assigned to the assignee of the present invention. The first axis is the center of the pass-through diameter, that is, the diameter of the smallest borehole the bit will pass through. Accordingly, this axis may be referred to as the pass-through axis. The second axis is the axis of the hole cut in the subterranean formation as the bit is rotated and may be referred to as the drilling axis. There is usually a first, lower and smaller diameter pilot section employed to commence the drilling, and rotation of the bit is centered about the drilling axis as the second, upper and larger diameter main bit section engages the formation to enlarge the borehole, the rotational axis of the bit assembly rapidly transitioning from the pass-through axis to the drilling axis when the full diameter, enlarged borehole is drilled.
In another conventional approach to enlarge a subterranean borehole, rather than employing a one-piece drilling structure such as an eccentric bit or a bi-center bit to enlarge a borehole below a constricted or reduced-diameter segment, it is also known to employ an extended bottom hole assembly (extended bi-center 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 bottom hole 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 structures 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 mid-portion 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. The mid-portion of the reamer wing also may include a stabilizing pad having an arcuate exterior surface having a radius that is the same as or slightly smaller than the radius of the pilot hole on the exterior of the tubular body and longitudinally below the blades. The stabilizer pad is characteristically placed on the opposite side of the body with respect to the reamer blades so that the reamer wing tool will ride on the pad due to the resultant force vector generated by the cutting of the blade or blades as the enlarged borehole is cut. U.S. Pat. No. 5,765,653, assigned to the assignee of the present invention, discloses the use of one or more eccentric stabilizers placed within or above the bottom hole reaming assembly to permit ready passage thereof through the pilot hole or pass-through diameter, while effectively radially stabilizing the assembly during the hole-opening operation thereafter.
Conventional expandable reamers 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 et al. In addition, U.S. Pat. No. 6,360,831 to Åkesson 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 way of a face thereof that is directly subjected to the pressure of the drilling fluid flowing through the body. However, the face, being directly exposed to the drilling fluid, may be subjected adversely to erosion or chemical effects caused thereby.
Notwithstanding the 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. For instance, bi-center and reamer wing assemblies are limited in the sense that the pass-through diameter is nonadjustable and limited by the reaming diameter. Further, conventional reaming assemblies may be subject to damage when passing through a smaller diameter borehole or casing section.
The present invention generally relates to an expandable reamer having movable blades that may be positioned at an initial smaller diameter and expanded to a subsequent diameter to ream and/or drill a larger diameter within a subterranean formation. Such an expandable reamer may be useful for enlarging a borehole within a subterranean formation below a particular depth, since the expandable reamer may be disposed within a borehole of an initial diameter and expanded, rotated, and displaced to form an enlarged borehole therebelow.
In one exemplary embodiment, the expandable reamer of the present invention may include an actuation sleeve whose position may determine deployment of a movable blade therein as described below. For instance, an actuation sleeve may be disposed within the expandable reamer and may have a reduced cross-sectional area aperture or orifice that drilling fluid passes through. Thus, the drilling fluid passing through the expandable reamer and reduced cross-sectional aperture or orifice may cause the actuation sleeve to be displaced by the force generated thereby. Sufficient displacement of the actuation sleeve may allow drilling fluid to communicate through apertures in the displaced actuation sleeve with movable blade sections, the pressure of the drilling fluid forcing the movable blades to expand radially or laterally outwardly. Further, the actuation sleeve may be biased in substantially the opposite direction of the force generated by drilling fluid passing through the reduced cross-sectional area of the actuation sleeve by way of a sleeve-biasing element. Such a sleeve-biasing element may cause the actuation sleeve to be repositioned, in the absence of, or against, the force generated by drilling fluid passing through the reduced cross-sectional orifice, thus preventing drilling fluid from communicating with the movable blades of the expandable reamer. Furthermore, the expandable reamer may include blade-biasing elements configured to return or bias the movable blades radially or laterally inward in the absence of, or against, the pressure of the drilling fluid acting on the movable blades. Moreover, a tapered or chamfered surface on the upper longitudinal region of each blade may also facilitate return of that movable blade inwardly as the taper or chamfer contacts the borehole wall. Thus, the expandable reamer of the present invention may return to its initial unexpanded condition depending on the position of the actuation sleeve.
In addition, the outermost position of the movable blades, when expanded, may be adjustable. For instance, the expandable reamer of the present invention may be configured so that an adjustable spacer element may be used to determine the outermost radial or lateral position of a movable blade. Such adjustable spacer element may generally comprise a block or pin that may be adjusted or replaced. In addition, in an embodiment including an actuation sleeve that enables the expansion of the movable blades, a sleeve-biasing element, and blade-biasing elements, the sleeve-biasing element may be configured in relation to the blade-biasing elements for the purpose of adjusting the conditions that may cause the movable blades to expand to their outermost radial or lateral positions. For instance, the sleeve-biasing element and reduced cross-sectional orifice may be configured so that a drilling fluid flow rate above a minimum drilling fluid flow rate causes the sleeve to be displaced, thus allowing drilling fluid to communicate with the movable blades. Accordingly, the blade-biasing elements may be configured so that only a drilling fluid flow rate exceeding the drilling fluid flow rate required to open communication between a movable blade and the drilling fluid may cause the movable blades to move radially or laterally outward to their outermost radial or lateral position.
The expandable reamer of the present invention is not limited to actuation sleeves for activating the expansion of the expandable reamer. Collets, shear pins, valves, burst discs, or other mechanisms that enable the expansion of the movable blades of the expandable reamer in relation to an operating condition thereof may be employed. Moreover, a flow restriction element may be disposed within the drill string to actuate the expansion of the expandable reamer. For instance, a ball may be disposed within the drilling fluid, traveling therein, ultimately seating within an actuation sleeve disposed at a first position. Pressure from the drilling fluid may subsequently build to force the ball and actuation sleeve, optionally held in place by way of a shear pin or other frangible member, into a second position, thereby actuating the expansion of the expandable reamer. Such a configuration may require that once the movable blades are expanded by the ball, in order to contract the movable blades, the flow is diverted around the seated ball to allow a maximum fluid flow rate through the tool. Thus, the expandable reamer may be configured as a “one-shot” tool, which may be reset after actuation.
Further, a pressure-actuated pin guide may be employed to cause the reamer to assume different operational conditions. More specifically, a pin guide may comprise a cylinder with a groove having alternating upwardly sloping and downwardly sloping arcuate paths formed at least partially along the circumference of the cylinder and a pin affixed to an actuation sleeve, the pin disposed within the groove. Alternating opposing forces may be applied to the pin and actuation sleeve assembly to cause the pin to traverse within the groove. One force may be created by way of drilling fluid passing through an orifice and an opposing force may be generated by way of a biasing element, as previously described in relation to an actuation sleeve and associated biasing element. For instance, a relatively high flow rate through the tool may cause the pin to traverse longitudinally downwardly within the groove. Upon the flow rate decreasing, a return force provided by way of the biasing element may cause the pin to traverse longitudinally upwardly within the groove. Further, the longitudinal position of the actuation sleeve may prevent or allow drilling fluid to communicate with the movable blades. Thus, the reamer may be caused to assume different operational conditions as the pin may be caused to traverse within the groove of the pin guide.
Thus, the expandable reamer of the present invention may be configured so that the movable blades expand to an outermost radial or lateral position under selected operating conditions as well as return to an inward radial or lateral position under selected operating conditions. Furthermore, movable blades disposed within the expandable reamer of the present invention may comprise tapered, spiral, or substantially straight longitudinally extending sections extending from the tubular body of the expandable reamer. It also may be advantageous to shape the movable blades so that the longitudinal sides of the movable blades are not straight. For instance, each longitudinal side of the movable blades may comprise an oval, elliptical, or other arcuate shape. Of course, the sides need not be symmetrical, but may be if so desired. Such a configuration may reduce binding of the movable blades as they move radially or laterally inwardly and/or outwardly.
Further, a movable blade of the present invention may be removable and/or replaceable. In one exemplary embodiment, removable lock rods extending through the body of the expandable reamer may be used to affix a spacing element associated with and configured to effectively retain the movable blade within the body of the expandable reamer. Accordingly, removable lock rods extending through the body of the expandable reamer and through the spacing elements may be selectively removed, thus allowing for the spacing element and movable blade to be repaired or replaced. Accordingly, such a configuration may allow for the expandable reamer of the present invention to be easily reconfigured for different diameters or repaired.
PDC cutting elements as described above may be affixed in pockets formed on the movable blades by way of an interference fit or brazing. Alternatively, cutting elements may comprise sintered tungsten carbide inserts (“TCI”) without a diamond layer; such a configuration may be useful for drilling out a section of casing, or creating a window within a casing section. Furthermore, blades may be fabricated with impregnated diamond cutting structures as known in the art. Alternatively, an expandable reamer may be configured with rotating roller cones having tungsten carbide inserts, PDC inserts, or steel inserts, as known in the art. Such a configuration may be particularly suited for drilling hard formations.
In addition, structures having an ovoid upper geometry may be disposed along the outer radial or lateral extent of a movable blade at one or more longitudinal positions thereof. Such ovoid structures may be desirable as inhibiting or preventing damage to proximate cutting elements disposed on a movable blade. For example, it may be possible for the respective longitudinal orientations of the expandable reamer or the movable blade to become tilted with respect to the longitudinal axis of the borehole, and cutting elements disposed on the movable blade may engage the sidewall of the borehole in an undesirable fashion. Thus, cutting elements may be damaged by prematurely or excessively contacting the sidewall of the borehole. Ovoid structures disposed along the movable blade may also inhibit or prevent excessive or premature contact between the sidewall of the borehole and associated cutting elements on the movable blade during certain types of operational conditions, such as whirling, rotation within a casing, or other unstable motion. Likewise, movable blades may be configured with rate-of-penetration (“ROP”) limiters and/or BRUTE® cutters, available from Hughes Christensen Company, located in Houston, Tex., as known in the art, to tailor the force/torque response of the expandable reamer during drilling operations.
In operating the expandable reamer of the present invention, it may be desirable to ascertain the operational state of the expandable reamer within the subterranean formation. To this end, a perceptible pressure response within the drilling fluid may indicate an operational state of the expandable reamer. For instance, upon drilling fluid communicating or ceasing to communicate with the movable blades, a perceptible pressure response may be generated. In one embodiment, some of the pressure communicating with the movable blades may be released through open nozzle orifices near each blade. This would result in a sudden decrease in pressure, indicating that the actuation sleeve has shifted to the lower position. In another embodiment, as the actuation sleeve is displaced so as to allow the drilling fluid passing through the reamer to communicate through apertures in the actuation sleeve with the movable blades, the internal pressure of the drilling fluid may drop noticeably. Subsequently, as the actuation sleeve is displaced to its lowermost longitudinal position and the blades expand to their outermost radial or lateral position, the pressure may increase perceptibly and may even increase over the steady-state operational pressure of the expandable reamer when the movable blades are expanded to their outermost radial or lateral position. In addition, a perceptible pressure response may occur as the drilling pressure drops, an actuation sleeve is displaced upwardly, and the drilling fluid within the reamer ceases to communicate with the movable blade sections.
Pressure response characteristics of the expandable reamer may also be changed or modified without removing the expandable reamer from the borehole. In one embodiment, an area restriction element may be positioned by way of a wireline to further reduce the area of the reduced cross-sectional area aperture. In addition, modification of the actuation sleeve apertures that allow the drilling fluid to communicate with the actuation mechanism or movable blades may be modified. Alternatively, a wireline may be used to remove an area restriction element from the reduced cross-sectional area aperture or the sleeve aperture(s) to modify pressure response characteristics of the expandable reamer.
Further, it may be advantageous to tailor the fluid path through the tool so that the pressure response to an operational state of the expandable reamer may be amplified or made more distinctive. One possible way to do this may be to provide a port that allows drilling fluid to pass through the body of the expandable reamer upon the drilling fluid becoming communicative with a movable blade, but as the movable blade expands radially or laterally outwardly, the port becomes increasingly sealed or blocked in relation to the displacement of the movable blade toward its outermost radial or lateral position. Thus, as the movable blade moves into an expanded lateral or radial position, the port becomes increasingly sealed or blocked thereby. In turn, as the port becomes blocked, the pressure within the expandable reamer may increase, forcing the blade outwardly and causing the port to be sealed. Such a phenomenon may exhibit a “positive feedback” type of behavior, where the drilling fluid pressure causes the port to restrict the flow of drilling fluid, thus increasing the drilling fluid pressure. Therefore, the drilling fluid pressure within the expandable reamer may rapidly increase as the movable blade(s) are displaced to their outermost radial or lateral position(s). Accordingly, the relatively rapid increase in drilling fluid pressure may be desirable as being detectable and indicating that a movable blade is positioned at its outermost position. Conversely, when a blade is not fully extended, the pressure will be lower. Of course, burst discs, shear pins, pressure accumulators, or other mechanical implements may be used to amplify or distinguish the pressure response of the drilling fluid to an operational state of the expandable reamer or a movable blade thereof.
The expandable reamer of the present invention may include static as well as dynamic seals. For instance, seals may be comprised of TEFLON®, polyetheretherketone (“PEEK™”) material, other plastic material, or an elastomer, or may comprise a metal-to-metal seal. Of course, dynamic seals within the tool may be disposed upon the blades as well. It may be advantageous to configure one or more backup wipers that “wipe” the surface that the seal engages. Accordingly, the one or more backup wipers may be configured with ridges that contact the surface intended to be cleaned or wiped. The one or more backup wipers may be configured to encounter the surface of engagement in the direction of movement prior to another seal or a main seal. Further, a backup wiper may also be disposed to surround a T-shaped seal, so that the T-shaped seal extends through or in between the backup wiper configuration. In such a configuration, the backup wiper may serve to inhibit the deformation and/or extrusion of the T-shaped seal.
In another aspect of the present invention, a lubricant compensator system may be included as part of any seals within the expandable reamer. Compensator systems are known in the art to be typically used within roller cone rotary drill bits for reducing the ability of drilling mud to enter the moving roller bearings within each cone. Within the present invention, a pressurized lubricant compensator system may be used to pressurize a seal or seal assembly, thus inhibiting contaminants from causing damage thereto or entering thereacross.
In another exemplary embodiment of the present invention, an oil-filled chamber and a separation element, such as a piston or membrane, may be configured so that the pressure developed by the drilling fluid may be transferred via the separation element and oil within the chamber to the movable blades. Such a configuration may protect the movable assemblies from contaminants, chemicals, or solids within the drilling fluid by transferring the drilling fluid pressure without contact of the drilling fluid with the movable blades of the expandable reamer.
In addition, at least one movable blade may be configured with a drilling fluid port to aid in cleaning the formation cuttings from the cutting elements affixed to the movable blades. In one exemplary embodiment, a drilling fluid port may be configured near the lower longitudinal cutters on the movable blade and may be oriented at an angle, for example, 15° from horizontal, toward the upper longitudinal end of the reamer. Alternatively, a drilling fluid port may be installed in the horizontal direction, perpendicular to the axis of the tool. A drilling fluid port may be located near to, or actually as a part of, an expanding blade. Other configurations for communicating fluid from the interior of the tubular body to the cutting elements on the movable blades are contemplated, including a plurality of fluid ports on at least one movable blade.
Another feature of an expandable reamer with movable blades that includes an actuation sleeve may be that, in case of a malfunction, the actuation sliding sleeve may be removed by a wireline with a fishing head configured to engage the reduced cross-sectional area orifice. Upon removal of the slidable sleeve, other operations or mechanical manipulation of the movable blades may be accomplished. Mechanisms for either actuating or returning movable blades that may be deployed by a wireline are also contemplated by the present invention. One example would be a linkage that could either force the blades radially or laterally inwardly or outwardly when provided with a force in a longitudinal direction.
Of course, many other mechanical arrangements for actuating the blades of the expandable reamer are contemplated by the present invention. For instance, the expandable reamer of the present invention may be actuated by mechanical means such as threaded elements, pistons, linkages, tapered elements or cams, or other mechanical configurations may be used. The blades may be hinged to allow for movement. Further, electromechanical actuators may be used, such as turbines, electrical motors coupled to worm gears, gears, lead screws, or other displacement equipment as known in the art. Accordingly, when controllable electromechanical means are used to actuate the movable reamer blades, a microprocessor may be used to control the position of the blades. Blade position may be controlled as a function of drilling conditions or other feedback. Also, the position of the blades may be programmed to respond to a measurable drilling condition. Thus, an expandable reamer of the present invention may be used to ream multiple desired diameters within a single borehole.
Alternatively, differently sized and/or spaced movable blades may be configured so that a first borehole diameter may be drilled at a first drilling fluid flow rate, and a second borehole diameter may be drilled at a second drilling fluid flow rate. For instance, a set of shear pins may restrain expansion of the movable blades up to a first drilling fluid pressure at a first radial or lateral position. Subsequently, drilling fluid pressure in excess of the first drilling fluid pressure may be applied to shear the set of shear pins and cause the movable blade sections to be displaced to another, more extended position. Many alternatives are contemplated for using the expandable reamer of the present invention to ream more than one size of borehole, including drilling a first larger borehole and a second smaller borehole, drilling a first smaller borehole and a second larger borehole, or simply drilling a first section of a borehole with a first plurality of movable blades configured to expand to a first diameter and a second section of the borehole with a second plurality of movable blades configured to expand to a second diameter.
In yet another exemplary embodiment, the expandable reamer of the present invention may be configured to enlarge a borehole relatively significantly. A single movable blade may be configured to expand and contract over a greater radial or lateral distance than multiple movable blades because interference between the movable blades may be eliminated. Thus, movable blades may be disposed at different axial positions and configured to radially or laterally expand and contract relatively significantly by utilizing space within the expandable reamer. Disposing movable blades at different axial positions along the axis of reaming may allow for the movable blades to extend and contract over a greater radial or lateral distance, since the interior of each movable blade may not interfere with the interior of another movable blade. Accordingly, the plenum for conducting drilling fluid may be disposed in an off-center manner if the movable blades extend into the center of the tool. In addition, more than one movable blade may be disposed at different axial and circumferential positions.
Further, the expandable reamer of the present invention may include a replaceable bearing pad disposed proximate to one end of a movable blade. Thus, in the direction of drilling/reaming, the replaceable bearing pad may longitudinally precede or follow the movable blade. Replaceable bearing pads may comprise hardfacing, diamond, tungsten carbide, or superabrasive materials. Further, a replaceable bearing pad may be configured to be affixed to and removed from the expandable reamer by way of removable lock rods extending along a longitudinal area of an expandable reamer as described hereinabove.
In addition, the expandable reamer of the present invention may include movable bearing pad sections that may be expanded radially or laterally outward under selectable operating conditions and are configured (if expanded) to engage the pilot borehole so as to stabilize the expandable reamer during reaming operations. The movable bearing pad sections may be actuated at substantially the same operating conditions as the movable blades of an expandable reamer or, alternatively, at differing operating conditions. It may be advantageous for the bearing pad sections to expand to their outermost radial or lateral position prior to the movable blades being actuated to their outermost radial or lateral position so as to stabilize the blades during their initial contact with the pilot borehole as well as during subsequent reaming operations. The expandable bearing pad sections may include biasing elements for returning the bearing pad sections to their innermost radial or lateral positions under selectable conditions. Movable bearing-pad-biasing elements may be adjustable from the outer surface of the tubular body of the expandable reamer to provide field-settable capabilities.
Although drilling fluid pressure may be the most available source for actuating movable blades and bearing pads, alternative sources are contemplated. For instance, it may be desirable to power an expandable reamer of the present invention by way of a downhole pump or turbine-generated electrical power. Downhole pumps or turbines may allow for an expandable reamer to be used when the flow rates and pressures that are required to actuate the tool are not available or desirable. Further, expansion or contraction of the movable blades of the expandable reamer of the present invention may be triggered by an external signal or condition such as a series of pressure pulses in the drilling fluid. Also, the movable blades may be actuated by weight-on-bit (WOB) force, torque, rotational forces, electrical energy, explosive charges or other energy sources.
Similarly, many different configurations may be employed for allowing drilling fluid pressure to communicate with movable blades of the present invention. The sliding sleeve actuation mechanism may be replaced with a hydraulic valve. In such a configuration, a sleeve may be used to separate the drilling fluid from the actuation fluid, the actuation fluid supplied by way of a turbine or other pressure-developing apparatus. Moreover, an electrically actuated valve may be configured to deploy a downhole motor, pump, or turbine that supplies drilling fluid pressure to the expandable reamer of the present invention, thus potentially eliminating the need for a sliding sleeve actuation mechanism.
Regardless of the actuation means for displacing the movable blades or bearing pads within the expandable reamer, the reamer may be configured so that the blades or bearing pads may be locked into a position. The locked position may be fully expanded or expanded to an intermediate position. Locking elements may slide in response to increasing drilling fluid pressure, or may comprise a tapered fit between a sliding element and the movable blades, or a locking mechanism such as linkages that engage the movable blades. Other locking mechanisms may be used as are known in the art.
Antiwhirl features as known in the art may be employed by the expandable reamer of the present invention. U.S. Pat. No. 5,495,899, assigned to the assignee of the present invention, describes a reaming wing assembly with antiwhirl features. More specifically, one of the movable blades may be configured to be a bearing surface, where the vector summation of the cutting element forces may be directed toward the bearing blade section. Accordingly, it may be advantageous to preferentially align the antiwhirl characteristics of the expandable reamer with the antiwhirl characteristics of the pilot bit. For instance, it may be advantageous to align the antiwhirl bearing pad of the expandable reamer with the antiwhirl bearing pad of the pilot bit.
The movable blades included within the expandable reamer of the present invention may be circumferentially symmetric, wherein each movable blade may be disposed at evenly spaced circumferential positions. Circumferentially asymmetric blade arrangements may also be employed, wherein movable blades may be placed at unevenly spaced circumferential positions. Asymmetric movable blade arrangements may require that blades exhibit different radial or lateral displacements so that each blade may be expanded to substantially identical outer radial or lateral extents.
Movable blades may be fabricated from steel or tungsten carbide matrix material, as known in the art. Steel movable blades may be hardfaced to increase their erosion and abrasion resistance. In addition, the expandable reamer of the present invention may include blades having chip breakers, typically used when drilling bit-balling shale formations, embodying a raised area on the blade surface proximate to the cutting elements for effecting improved cuttings removal. The raised area of the chip breaker causes a formation chip being cut to be forced away from the blade surface, thereby causing the formation chip to break away from the blade. The chip breaker may be a ramped surface, such as the ramped surface of the chip breakers disclosed in U.S. Pat. No. 5,582,258, assigned to the assignee of the present invention, and may include a protrusion positioned proximate each cutting element on the surface of the bit face such that, as a formation shaving slides across the cutting face of the cutting element, the protrusion splits and/or breaks up the chip into two or more segments as disclosed in U.S. Pat. No. 6,328,117, also assigned to the assignee of the present invention. Moreover, the expandable reamer of the present invention may be coated with a coating to enhance its durability or with a non-stick coating to reduce balling characteristics.
Features from any of the above-mentioned embodiments may be used in combination with one another in accordance with the present invention. Other features and advantages of the present invention will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.
In the drawings, which illustrate what is currently considered to be the best mode for carrying out the invention:
FIG. 1D1 is a perspective schematic view of one embodiment of a movable blade-retention apparatus and FIG. 1D2 is a partial sectional perspective schematic taken transverse to the longitudinal extent of the movable blade-retention apparatus of FIG. 1D1;
Referring to
In
Actuation sleeve 40 may be positioned longitudinally in a first position, where apertures or ports 42 are above actuation seal 43. Drilling fluid (not shown) may pass through actuation sleeve 40, thus passing by movable blades 12 and 14. Actuation seal 43 and lower sleeve seal 45 may prevent drilling fluid from interacting with movable blades 12 and 14. Further, sleeve-biasing element 44 may provide a bias force to actuation sleeve 40 to maintain its longitudinal position. However, as drilling fluid passes through actuation sleeve 40, a reduced cross-sectional orifice 50 may produce a force upon the actuation sleeve 40. As known in the art, drag of the drilling fluid through the reduced cross-sectional orifice 50 may cause a downward longitudinal force to develop on the actuation sleeve 40. As the drilling fluid force on the actuation sleeve 40 exceeds the force generated by the sleeve-biasing element 44, the actuation sleeve 40 may move longitudinally downward thereagainst. Thus, the longitudinal position of the actuation sleeve 40 may be modified by way of changing the flow rate of the drilling fluid passing therethrough. Alternatively, a collet or shear pins (not shown) may be used to resist the downward longitudinal force until the shear point of the shear pin or frictional force of the collet is exceeded. Thus, the downward longitudinal force generated by the drilling fluid moving through the reduced cross-sectional orifice 50 may cause a frangible or frictional element to release the actuation sleeve 40 and may cause the actuation sleeve 40 to move longitudinally downward.
Further, the longitudinal position of the actuation sleeve 40 may allow drilling fluid to be diverted to inner surfaces 21 and 23 of movable blades 12 and 14, respectively, via apertures or ports 42. In opposition to the force of the drilling fluid upon the inner surfaces 21 and 23 of movable blades 12 and 14, blade-biasing elements 24, 26, 28, and 30 may be configured to provide an inward radial or lateral force upon movable blades 12 and 14. However, drilling fluid acting upon the inner surfaces 21 and 23 may generate a force that exceeds the force applied to the movable blades 12 and 14 by way of the blade-biasing elements 24, 26, 28, and 30, and movable blades 12 and 14 may, therefore, move radially or laterally outwardly. Thus, expandable reamer 10 is shown in an expanded state in
Thus,
Further, at least one movable blade 12 of the expandable reamer 10 may be configured with a port 34 to aid in cleaning the formation cuttings from the cutting elements 36 affixed to the movable blades 12 and 14 during reaming. As shown in
Movable blades 12 and 14 may also be caused to contract radially or laterally. For instance, as the drilling fluid pressure decreases, blade-biasing elements 24, 26, 28, and 30 may exert a radial or lateral inward force to bias movable blades 12 and 14 radially or laterally inward. In addition, taper 19 may facilitate movable blades 12 and 14 returning radially or laterally inwardly during tripping out of the borehole if the blade-biasing elements 24, 26, 28, and 30 fail to do so. Specifically, impacts between the borehole and the taper 19 may tend to move the movable blades 12 and 14 radially or laterally inward.
FIGS. 1D1 and 1D2 show an embodiment of a movable blade-retention apparatus 201 consistent with the embodiments of expandable reamer 10, as shown in
As may also be seen in FIGS. 1D1 and 1D2, the cross-sectional shape of the movable blade 12 as it extends through the retention element 16 may be oval or elliptical. Such a shape may prevent binding of the movable blade 12 as it is moved laterally inwardly and outwardly during use. Thus, the shape of the longitudinal sides of the movable blades 12 and 14 may not be straight. For instance, each longitudinal side of a movable blade may comprise an oval, elliptical, or other arcuate shape. Further, the sides need not be symmetrical, but may be if symmetry is desirable.
As shown in
Ovoid structures 37 may comprise a sintered tungsten carbide compact having a domed or ovoidal top surface. However, ovoid structures 37 may comprise generally or partially planar or flat, cylindrical, conical, spherical, rectangular, triangular, or arcuate shapes, and/or be otherwise geometrically configured and suitably located to provide protection to associated cutting elements 36. The present invention is not limited only to sintered tungsten carbide ovoid structures; ovoid structures may comprise other metals, sintered metals, alloys, diamond, or ceramics.
In one example, under certain orientations of the expandable reamer or the movable blades, cutting elements 36 disposed on the movable blades 12 and 14 may engage the sidewall of the borehole in an undesirable fashion. Thus, cutting elements 36 may be damaged by prematurely or excessively contacting the sidewall of the borehole. Ovoid structures 37 disposed along the movable blades 12 and 14 may inhibit or prevent excessive or premature contact between the sidewall of the borehole and the cutting elements 36 on the movable blades 12 and 14.
As shown in
More particularly, ovoid structures 37 may be sized and positioned to initially exhibit substantially the same exposure as cutting elements 36 proximate thereto. However, ovoid structures 37 may also exhibit a relatively lower wear resistance to the formation. Thus, upon initially disposing the expandable reamer 10 within the borehole, the ovoid structures 37 may wear away, thus allowing the cutting elements 36 to assume a selected depth-of-cut into the formation. This may be advantageous because the ovoid structure 37 may prevent initial impact loading by making contact with the borehole or other surface at substantially the same exposure as the cutting elements 36 proximate thereto. Further, the ovoid structures 37, upon wearing, may limit contact between cutting elements 36 proximate thereto and the formation according to the amount of wear thereon. Additionally, cutting elements 36 and associated ovoid structures 37 may be replaced and ground (if necessary) to a desirable exposure, respectively.
The present invention contemplates that ovoid structures 37 may also inhibit excessive contact between associated cutters and the formation during unstable motion of the expandable reamer, i.e., whirling or when the expandable reamer is rotated inside the casing. Thus, movable blades 12 and 14 need not exhibit particular orientations or be tilted in order to benefit from ovoid structures 37. Ovoid structures 37 may be utilized within any of the embodiments described herein, without limitation.
As a further embodiment of the present invention, expandable reamer 410 is shown in
As depicted in
Actuation sleeve 440 may include a reduced cross-sectional orifice 450, which, in turn, may produce a downward longitudinal force as drilling fluid passes therethrough. Upon sufficient downward longitudinal force developing, the actuation sleeve 440 may be displaced longitudinally, as shown in
By configuring the expandable reamer 410 with an actuation sleeve 440 that may be displaced substantially the longitudinal length of the movable blades 412 and 414, several advantages may be realized. For instance, as may be seen in
Expandable reamer 710, as depicted in
Actuation sleeve 740 may include a reduced cross-sectional orifice 750 and may be displaced longitudinally in a fashion similar to the embodiments described hereinabove, in that drilling fluid flowing therethrough may produce a longitudinally downward force on the actuation sleeve 740.
Longitudinal displacement of actuation sleeve 740 below inner seal element 745 may allow drilling fluid to act upon inner surfaces 721 and 723 of movable blades 712 and 714, respectively, causing them to expand radially or laterally outwardly against the opposing forces of blade-biasing elements 724 and 726, as well as 728 and 730, retained by retention elements 716 and 720, respectively. Of course, movable blades 712 and 714 may return radially or laterally inwardly as the forces applied thereto by way of blade-biasing elements 724 and 726, as well as 728 and 730, respectively, exceed the forces of the drilling fluid upon the inner surfaces 721 and 723 of movable blades 712 and 714, respectively.
As may further be seen with respect to
As depicted in
However, a restriction element 266 may be deployed within the drilling fluid stream and may ultimately be disposed within sleeve seat 252, as shown in
In addition, the longitudinal position of the actuation sleeve 240 after the restriction element 266 is deployed, as shown in
In order to allow drilling fluid to pass through the expandable reamer 210, the actuation sleeve 240 may be configured with grooves 258 formed within but not through the thickness of the actuation sleeve 240 that do not extend below the lower sleeve seal 245 in the position as shown in
At least one movable blade of the expandable reamer 210 may be configured with a port 234 to aid in cleaning the formation cuttings from the cutting elements 236 affixed to the movable blades 212 and/or 214 during reaming/drilling. Port 234 may be configured near the lower longitudinal cutting elements 236 on the movable blade 212 and may be oriented at about 15° from the horizontal toward the upper longitudinal end of the expandable reamer 210. Of course, the present invention contemplates that a port 234 may be oriented as desired. Port 234 may be located near to, or actually as a part of, movable blade 212, as shown. Other configurations for communicating fluid from the interior of the tubular body 232 to the cutting elements 236 on the movable blades 212 and 214 are contemplated, including a plurality of ports 234 on at least one movable blade.
Accordingly, after radial or lateral expansion of movable blades 212 and 214, movable blades 212 and 214 may be caused to contract when the drilling fluid pressure decreases sufficiently so that blade-biasing elements 224, 226, 228, and 230 may exert a radially or laterally inward force to bias movable blades 212 and 214 radially or laterally inward. As noted hereinabove, a taper 219 may facilitate movable blades 212 and 214 returning radially or laterally inwardly via contact between the taper 219 and any other surface or body.
As a further aspect of the present invention, a pin guide sleeve assembly 360 as shown in
Therefore, considering the beginning at position A1 as shown in
In a further embodiment of the present invention, an expandable reamer sub 310 with a movable blade 312 having an expanded outermost diameter that may exceed the diameter that is ordinarily attainable via conventional expandable reamers is shown in
Expandable reamer sub 310 includes tubular body 332, bore 331, and movable blade 312 carrying cutting elements 336. In such a configuration, inner surface 321 of movable blade 312 may extend into the space near and past a longitudinal axis 325 (center) of the expandable reamer sub 310. Due to space limitations, where multiple movable blades are disposed with overlapping longitudinal extents, the radially inner surfaces may only extend to the longitudinal axis 325 of the expandable reamer sub 310. Retaining structures 350 and 352 may be disposed near the center of the expandable reamer sub 310, as shown in
However, since it may be preferred to drill with multiple reaming/drilling blades, multiple expandable reamer subs 310 may be assembled together or to other drilling equipment via female-threaded box connection 315 and male-threaded pin connection 311. Accordingly, each movable blade 312 of each expandable reamer sub 310 may be aligned circumferentially as desired in relation to one another. For instance, three expandable reamer subs 310 may be assembled so that each movable blade 312 is circumferentially separated from another movable blade 312 by about 120°. Of course, many different assemblies containing different numbers of movable blades in different arrangements are contemplated by the present invention.
During operation, movable blade 312 may be pinned into place by way of shear pins (not shown) disposed within holes 361 and 363 extending into respective holes within movable blade 312, as known in the art. Further, bias forces applied by way of blade-biasing elements 324 and 326 may provide forces to retain the movable blade 312 against the retaining structures 350 and 352. However, as drilling fluid pressure may be increased, the forces generated thereby may cause shear pins (not shown) within holes 361 and 363 and extending into movable blade 312 to fail. In turn, the pressure of the drilling fluid on the inner surface 321 of the movable blade 312 may cause the movable blade 312 to be disposed radially or laterally outwardly, matingly engaging retention element 316 as shown in
Turning to
Furthermore, different movable blades may be configured to drill at different diameters.
In any of the above embodiments of expandable reamers of the present invention, adjustable spacer elements may be employed so that an expandable reamer may be adjustable in its reaming diameter. Such a configuration may be advantageous to reduce inventory and machining costs, and for flexibility in use of the expandable reamer.
Also applicable generally to the embodiments of the present invention including movable blades is a particular seal arrangement, as shown in
Moreover, compensator systems may be employed in combination with any dynamic seals of the present invention. As an example, a compensator system such as the compensator system for roller cone rotary drill bits disclosed in U.S. Pat. No. 4,727,942, assigned to the assignee of the present invention and incorporated herein in its entirety by reference, may be included within the expandable reamer of the present invention.
As shown in
Compensator 470 may substantially equalize drilling fluid pressure with lubricant pressure and may cause lubricant 477 to be supplied to a seal (not shown). Flexible diaphragm 474 having a small perforation 476 therein may be exposed on one side to the pressure of the drilling fluid and on the other side to lubricant 477 supplied to a bearing or seal (not shown). If the pressure of the lubricant 477 exceeds the pressure of the drilling fluid, a portion of lubricant 477 may be released through the small perforation 476 into the drilling fluid, thereby substantially equalizing the pressure of the lubricant 477 to the drilling fluid pressure. If the pressure of the drilling fluid exceeds the pressure of the lubricant 477, the small perforation 476 may be effectively sealed thereby, and the flexible diaphragm 474 may deform to push a portion of lubricant 477 through aperture 475 and into lubricant delivery tube 480. Lubricant delivery tube 480 may typically communicate with a seal (not shown), thereby supplying lubricant 477 thereto.
As shown in
In another exemplary embodiment of the present invention, a separation element actuation system may actuate as well as maintain the cleanliness and functionality of movable blades 512 and 514 of expandable reamer 510 of the present invention.
Thus, during operation, separation element 560 may be positioned longitudinally in a first position, as shown in
As the longitudinal position of the separation element 560 changes, fluid within the upper chamber 513 may be transferred into the annulus 517 and pressure may develop therein. Thus, pressure developed within annulus 517 acts on the inner surfaces 521 and 523 of movable blades 512 and 514, respectively, against forces generated by way of blade-biasing elements 524, 526, 528, and 530. Sufficient pressure acting upon the inner surfaces 521 and 523 may cause the movable blades 512 and 514 to move radially or laterally outwardly to an outermost radial or lateral position, matingly engaging retention elements 516 and 520, respectively, as shown in
Alternatively, instead of a separation element that transmits or communicates pressure or forces to another fluid in communication with movable blades, movable blades of the present invention may be separated from drilling fluid by way of a fixed barrier. For instance, in reference to
In a further aspect of the present invention,
Movable bearing pads may also be included within the expandable reamer of the present invention.
The position of actuation sleeve 140 may allow or prevent drilling fluid from acting upon inner surfaces 121 and 123 of movable blades 112 and 114, respectively, as well as inner surfaces 151 and 153 of movable bearing pads 152 and 154, respectively. More specifically, actuation sleeve 140 may include a reduced cross-sectional orifice 150 configured to develop force thereon by way of drilling fluid flowing therethrough. Thus, in an initial position (not shown) apertures 142 may be positioned above actuation seal 143, preventing drilling fluid from acting on either the movable blades 112 and 114 or movable bearing pads 152 and 154. In addition, seal 145 may prevent drilling fluid passing through the actuation sleeve 140 from communicating with annulus 117. However, upon sufficient force developed by way of drilling fluid passing through the reduced cross-sectional orifice 150, the actuation sleeve 140 may move to a longitudinal position as shown in
Therefore, operation of expandable reamer 101 is generally similar to the operation described hereinabove with respect to
In a further exemplary embodiment of the expandable reamer of the present invention, the vector sum of the cutting forces may be directed toward a fixed bearing pad or movable bearing pad.
The vector sum of the forces generated by PDC cutting elements 254 carried by pilot drill bit 256 during drilling may be directed along direction vector 175. Likewise, the vector sum of the forces generated by PDC cutting elements 340 carried by expandable reamer 300 may be directed along direction vector 175. In doing so, the vector sum of the cutting forces of PDC cutting elements 254 carried by the pilot drill bit 256 may be directed toward the drill bit bearing pad 264. Further, the vector sum of the cutting forces of PDC cutting elements 340 carried by expandable reamer 300 may be directed toward movable bearing pad 302. Such a configuration may be advantageous as inhibiting whirl motion of the expandable reamer assembly 301. Alternatively, the drill bit bearing pad 264 and the movable bearing pad 302, as well as the respective sum of the cutting forces of each, may be directed to different circumferential positions to improve operational characteristics of the expandable reamer assembly 301. Thus, antiwhirl concepts may be applied to the movable blades, fixed bearing pads, and movable bearing pads of an expandable reamer of the present invention in any combination with drill bits and associated antiwhirl configurations.
As mentioned hereinabove, perceptible drilling fluid pressure responses may indicate an operational state of an expandable reamer of the present invention, and it may be advantageous to configure an expandable reamer of the present invention to exhibit such drilling fluid pressure responses.
Accordingly, as described above, the actuation sleeve configuration and movable blade configuration may be selectively tailored to correspondingly affect the drilling fluid pressure response in relation to an operational characteristic of the expandable reamer. Further, the present invention also contemplates additional alternatives for tailoring a drilling fluid pressure response during operation of an expandable reamer. For instance, the activation mechanism of the expandable reamer may be designed to gradually or suddenly prevent or allow communication of the drilling fluid with the movable blade sections, thus potentially creating differing drilling fluid pressure responses. Further, a fluid aperture or port that is included in an expandable reamer may be configured with at least one burst disc, which may be designed to rupture at a selected pressure and may generate a perceptible drilling fluid pressure response. Additionally, fluid aperture sizes, annulus sizes, and biasing elements may be tailored to enhance or modify the drilling fluid pressure response characteristics of an expandable reamer during operation thereof.
Further, it may be advantageous to tailor the fluid path through the expandable reamer in relation to an operational state thereof.
As in other embodiments of the expandable reamer of the present invention described herein, the position of actuation sleeve 640 may allow or prevent drilling fluid from acting upon inner surfaces 621 and 623 of movable blades 612 and 614, respectively. Specifically, actuation sleeve 640 may include a reduced cross-sectional orifice 650 configured to develop force thereon by way of drilling fluid flowing therethrough. Thus, in an initial position (not shown), apertures 642 may be positioned above an actuation seal 643, preventing drilling fluid from acting on movable blades 612 and 614, as shown in
In relation to a fluid path that may be tailored to generate an amplified or distinctive drilling fluid pressure response, as shown in
Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some exemplary embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the invention, as disclosed herein, which fall within the meaning and scope of the claims are to be embraced thereby.
This application is a continuation of U.S. patent application Ser. No. 13/213,641, filed Aug. 19, 2011, scheduled to issue as U.S. Pat. No. 8,215,418 on Jul. 10, 2012, which application is a continuation of U.S. patent application Ser. No. 12/749,884, filed Mar. 30, 2010, now U.S. Pat. No. 8,020,635, issued Sep. 20, 2011, which is a continuation of U.S. patent application Ser. No. 11/875,241, filed Oct. 19, 2007, now U.S. Pat. No. 7,721,823, issued May 25, 2010, which application is a continuation of U.S. patent application Ser. No. 11/413,615, filed Apr. 27, 2006, now U.S. Pat. No. 7,308,937, issued Dec. 18, 2007, which is a continuation of U.S. patent application Ser. No. 10/624,952, filed Jul. 22, 2003, now U.S. Pat. No. 7,036,611, issued May 2, 2006, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/399,531, filed Jul. 30, 2002, for EXPANDABLE REAMER APPARATUS FOR ENLARGING BOREHOLES WHILE DRILLING AND METHOD OF USE. This application is also related to U.S. patent application Ser. No. 10/999,811, filed Nov. 30, 2004, now U.S. Pat. No. 7,549,485, issued Jun. 23, 2009, and to U.S. patent application Ser. No. 11/875,651, filed Oct. 19, 2007, now U.S. Pat. No. 7,681,666, issued Mar. 23, 2010. The entire disclosure of each of the above-identified patent applications and patents is hereby incorporated herein by this reference. This application is also related to U.S. patent application Ser. No. 11/873,346, filed Oct. 16, 2007, now U.S. Pat. No. 7,594,552, issued Sep. 29, 2009.
| Number | Date | Country | |
|---|---|---|---|
| 60399531 | Jul 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13213641 | Aug 2011 | US |
| Child | 13544744 | US | |
| Parent | 12749884 | Mar 2010 | US |
| Child | 13213641 | US | |
| Parent | 11875241 | Oct 2007 | US |
| Child | 12749884 | US | |
| Parent | 11413615 | Apr 2006 | US |
| Child | 11875241 | US | |
| Parent | 10624952 | Jul 2003 | US |
| Child | 11413615 | US |
