Abstract:
A drilling sub assembly adapted to be coupled between a drill bit of a drilling rig and a drill pipe, the drilling sub assembling including a turbine unit directly coupled to the drill bit via a mandrel, such that passage of a drilling fluid through the drilling sub assembly rotates the turbine unit which in turn directly rotates the drill bit coupled thereto. The present invention further relates to a baffle for controlling and reducing debris present within a drilling fluid used in combination with the drilling sub assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to systems and methods for providing a hydraulic drilling sub assembly for use in the excavation, mining and drilling fields. Specifically, the present invention relates to a drilling sub assembly incorporating a hydraulically driven turbine that directly drives a drill bit without the use of gears or other mechanical means to limit the rate of rotation for the drill bit. 
     2. Background and Related Art 
     As the world becomes increasingly populated and developed, greater demands are made on the world&#39;s supply of natural resources. For example, as technology becomes increasingly accessible and affordable to third-world countries, demands for ground water, natural gas, and petroleum also increase. As a result, greater efforts have been required to recover these natural resources to meet the growing demands of the world&#39;s population. To address these challenges, the service industry must develop new technology while improving existing products to provide economical solutions to efficiently tap deep reservoirs of natural resources. 
     Hydraulic drilling is the process of using turbines to rotate a drill bit. As a drilling fluid is passed over the turbine, the turbine is rotated thereby causing the drill bit to rotate. Typically, a drilling fluid is delivered to the turbine via a string of drill pipes extending from the surface to the turbine. There are many types of drilling fluids including air, air and water, air and polymer, water, water-based mud, oil based mud, and synthetic-based fluid. On a drilling rig, drilling fluid (sometimes referred to as mud) is pumped from mud pits through the drill string where it sprays out of nozzles on the drill bit, cleaning and cooling the drill bit in the process. The mud then carries the crushed or cut rock up the annular space between the drill string and the sides of the hole being drilled. These cuttings are then driven up through the surface case where they emerge back at the surface. 
     The rate of rotation for the drill bit is commonly controlled by incorporating reducer gears between the turbine and the drill bit. In this way, one can select the speed of the bit by selecting an appropriate gear ratio for a given application. However, several difficulties exist with this method of speed control. 
     For example, reducer gears are commonly exposed to sediments and other debris found in the drilling fluid. Debris within the drilling fluid can become lodged within the reducer gears causing jams and other malfunctions that must be cleared. The process of clearing these jams are time consuming, expensive and potentially damaging to the drilling equipment. Furthermore, in the event that the drill bit becomes jammed while cutting the rock, the inclusion of reducer gears prevents the drill bit from spinning freely in a direction opposite to the jam. Accordingly, the process of undoing the jam results in downtime and may result in damage to the drill bit and other components of the drilling string. 
     Thus, while techniques currently exist for hydraulic drilling applications, challenges still exist with such techniques. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to systems and methods for providing a hydraulic drilling sub assembly for use in the excavation, mining and drilling fields. Specifically, the present invention relates to a drilling sub assembly incorporating a hydraulically driven turbine that directly drives a drill bit without the use of gears or other mechanical means to limit the rate of rotation for the drill bit. 
     In some implementations of the present invention, a drilling sub assembly is provided as a means for converting an upstream drilling fluid into a rotational force that directly drives a drill bit. Thus, in some implementations the drilling sub assembly is interposedly coupled between a string of drill pipes and a drill bit. 
     The drilling sub assembly generally includes an upper component, a mid component and a lower component, each component having an internal space through which a drilling fluid is capable of flowing. The upper component includes a body casing having an internal lumen for housing a baffle and a turbine unit. The baffle includes a fluid channel through which drilling fluid is directed and applied directly to the turbine unit. The position of the baffle is maintained within the internal lumen such that the baffle is prevented from rotating within the internal lumen. However, a bearing is interposed between the baffle and the turbine unit such that the turbine unit is permitted to rotate relative to the baffle. Thus, as the drilling fluid leaves the baffle and contacts the turbine unit, the turbine unit rotates freely relative to the fixed position of the baffle and body casing. 
     The mid component includes a bearing housing having a plurality of bearing surfaces for supporting various bearing units. The bearing housing is threadedly coupled to the body casing such that a first bearing unit is interposedly positioned between the bearing housing and the turbine unit. 
     The lower component includes a mandrel having a base from which extends a shaft. The shaft is extends through the bearing housing and is threadedly coupled to the turbine unit. A second bearing unit is interposedly positioned between the base portion of the mandrel and the bearing housing. The interposing second bearing unit thereby permits the mandrel to rotate freely relative to the fixed position of the bearing housing. Thus, as the drilling fluid rotates the turbine unit, the direct coupling between the turbine unit and the mandrel causing the mandrel to rotate at the same rate as the turbine unit. 
     A free end of the body casing includes a set of threads for threadedly coupling the drilling sub assembly to an upstream drill pipe. Furthermore, a free end of the mandrel includes a set of threads for threadedly coupling a drill bit. Thus, as the drilling fluid flows through the baffle and over the turbine unit, the turbine unit and coupled mandrel rotate thereby rotating the coupled drill bit relative to the fixed positions of the drill pip, the body casing, the baffle and the bearing housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only typical embodiments of the invention and are not therefore to be considered to limit the scope of the invention. 
         FIG. 1  is a perspective view of a drilling rig assembly incorporating a drilling sub assembly in accordance with a representative embodiment of the present invention. 
         FIG. 2  is a cross-section view of a drilling sub assembly in accordance with a representative embodiment of the present invention. 
         FIG. 3  is a cross-section view of body casing in accordance with a representative embodiment of the present invention. 
         FIG. 4A  is a perspective view of a baffle in accordance with a representative embodiment of the present invention. 
         FIG. 4B  is a cross-section view of a baffle in accordance with a representative embodiment of the present invention. 
         FIG. 5A  is a perspective view of a turbine unit in accordance with a representative embodiment of the present invention. 
         FIG. 5B  is a partial cross-section view of a turbine unit in accordance with a representative embodiment of the present invention. 
         FIG. 5C  is a cross-section view of a turbine unit in accordance with a representative embodiment of the present invention. 
         FIG. 6  is a cross-section view of a turbine unit threadedly coupled to a mandrel and a first bearing unit in accordance with a representative embodiment of the present invention. 
         FIG. 7  is a cross-section view of a mandrel in accordance with a representative embodiment of the present invention. 
         FIG. 8  is a cross-section view of a partially assembled drilling sub assembly in accordance with a representative embodiment of the present invention. 
         FIG. 9  is a cross-section view of a bearing housing in accordance with a representative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The presently preferred embodiments of the present invention will be best understood by reference to the drawings, wherein like reference numbers indicate identical or functionally similar elements. It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description, as represented in the figures, is not intended to limit the scope of the invention as claimed, but is merely representative of presently preferred embodiments of the invention. 
     Referring now to  FIG. 1 , an implementation of a drilling sub assembly  10  is shown as interposedly coupled between a drill pipe  12  and a drill bit  14 . The drill pipe  12  generally includes an elongate tubular member having an internal lumen for transferring a drilling fluid from the surface to the drill bit  14 . The drill bit  14  generally includes a drill bit or another known cutting surface configured to cut a borehole  16 . In some embodiments, the drill bit  14  further includes a fluid outlet whereby drilling fluid is released through the drill bit  14  to assist in removing debris from the borehole  16 . The debris are removed to the surface via the interstitial space  18  between the drill pipe  12  and the borehole  16 , as is known in the art. 
     In general, the drilling sub assembly  10  is provided as a means for converting the flow of drilling fluid into a rotational force at the drill bit  14 . Specifically, the drilling sub assembly  10  utilizes a turbine unit to convert the linear flow of drilling fluid into a rotational force needed to rotate the drill bit  14 . 
     Some embodiments of the drilling sub assembly  10  comprise a modular unit having a plurality of interconnected sections. Each section is configured to work compatibly with the remaining sections to achieve desired working conditions for the drill bit  14 . For example, in some embodiments the drilling sub assembly  10  includes an upper component  20 , a mid component  30  and a lower component  40 . The upper component  20  generally comprises a body casing having a first end  22  for threadedly coupling the drill pipe  12 . The upper component  20  further comprises a second end  24  for threadedly coupling the mid component  30  or bearing housing of the drilling sub  10 . 
     The bearing housing  30  houses various bearing units to permit free rotation of the lower component  40  or mandrel relative to the stationary drill pipe  12 , body casing  20  and bearing housing  30 . The mandrel  40  comprises a threaded end  42  for coupling the drill bit  14 . Thus, the various components  20 ,  30  and  40  of the drilling sub assembly  10  are configured to achieve gearless rotation of the drill bit  14 , as further described below. 
     Referring now to  FIG. 2 , a cross-section view of the drilling sub assembly  10  is shown, as isolated from the drill pipe and the drill bit. The upper component  20  or body casing generally comprises an elongate tubular member having an internal lumen  26 , as shown in  FIGS. 2 and 3 . The internal lumen  26  is generally configured to include various diameters to receive internal components of the sub assembly  10 . For example, in some embodiments the internal lumen  26  houses a baffle  50  adjacent to the first end  22  opening. The baffle  50  generally comprises a plug having a fluid channel  52  for directing and focusing a drilling fluid to selectively interact with downstream internal components. The position of the baffle  50  within the internal lumen  26  is generally maintained via a set screw  100 . Set screw  100  not only maintains the vertical position of baffle  50 , but also prevents baffle  50  from rotating relative to the body casing  20 . In some embodiments, a plurality of set screws  100  is provided to maintain the position of baffle  50 . In other embodiment, an o-ring  110  or other means for sealing is further interposed between the baffle  50  and the internal lumen  26  to prevent drilling fluid from bypassing the baffle  50 . 
     Baffle  50  comprises a first end  54  and a second end  56 , as shown in  FIGS. 2 ,  4 A and  4 B. The first end  54  comprises an upper chamber  70  for receiving an upstream drilling fluid. The upper chamber  70  is generally cylindrical having a bottom surface  74  that is slanted or oblique relative to the vertical walls  76  of the chamber  70 . The upper chamber  70  further includes a plurality of windows  78  in fluid communication with fluid channel  52 . Fluid channel  52  generally comprises a groove on the external surface of baffle  50 , wherein the inner surface  28  of the internal lumen  26  combines with the groove to complete the fluid channel  52 . Thus, the out diameter of baffle  50  is selected to minimize any tolerance between the baffle  50  and the inner surface  28  of the body casing  20 . 
     In some embodiments, fluid channel  52  comprises a first portion  60  and a second portion  62 , as shown in  FIG. 4A . First portion  60  is generally vertically oriented. However, second portion  62  is generally angled thereby redirecting the flow of the drilling fluid. The combined features of first and second portion  60  and  62  thereby provide means for directing the drilling fluid to selectively interact with a downstream internal component. In some embodiments, first portion  60  is angled to be aligned with second portion  62 . In other embodiments, second portion  62  is aligned vertically with first portion  60 . Still further, in other embodiments baffle  50  comprises more than two fluid channels  52 . 
     The slanted configuration of bottom surface  74  naturally provides the upper chamber  70  with varying depths. The portion of the upper chamber  70  having the greatest depth experiences aberrant currents as the drilling fluid flows down the slanted surface into the vertical interior wall  80 . In particular, drilling fluid within this portion of the upper chamber  70  experiences eddies that churn and otherwise mix the drilling fluid. 
     In some embodiments, unwanted debris within the drilling fluid gravitate to this portion of the upper chamber  70  where they are subjected to aberrant currents that reduce the size and/or trap the unwanted debris. Eventually, the unwanted debris is sufficiently reduced in size and thereby released from the aberrant current and permitted to exit the upper chamber  70  via the window  78 . In some embodiments, the dimensions of window  78  are selected to prevent passage of unwanted debris having a size sufficient to harm or jam downstream internal components. Accordingly, the combined features of the slanted bottom surface  74  and the plurality of windows  78  prevents jams and other malfunctions due to debris in the drilling fluid. 
     The second end  56  of baffle  50  comprises a lower chamber  72  for rotatably receiving a downstream internal component. In particular, lower chamber  72  comprises a recess for compatibly receiving a first end  92  of a turbine unit  90 , as shown in FIGS.  2  and  5 A- 5 C. 
     Turbine unit  90  generally comprises a cylindrical body having an outer sleeve  96  and an internal lumen  98 . A plurality of blades  120  is set within the internal lumen  98  whereby a drilling fluid is permitted to pass over the blades  120  and through the internal lumen  98 . The turbine unit  90  is positioned within the recess of the lower chamber  72  of the baffle  50  such that an outlet  64  of the fluid channel  52  (see  FIG. 4A ) guides the drilling fluid to directly contact the plurality of blades  120 . Thus, in some embodiments the second portion  62  of the fluid channel  52  is positioned at an angle  66  to achieve a desired contact between the drilling fluid and the plurality of blades  120 . For example, in some embodiments angle  66  is selected to be 90° to the plurality of blades  120 . In other embodiments, angle  66  is selected to be less than or greater than 90° to the plurality of blades  120 . 
     A second end  94  of the turbine unit  90  comprises a threaded opening  114  through which the drilling fluid exits the internal lumen  98 . As the drilling fluid passes over the blades  120 , the turbine unit  90  is activated resulting in rotation of unit  90 . 
     The first end  92  of the turbine unit  90  further includes a bearing surface  102  for supporting a bearing unit  112 , such as a sealed bearing. A complimentary bearing surface  122  is located in lower chamber  72  of baffle  50 . Thus, bearing unit  112  permits free rotation of turbine unit  90  relative to the stationary positions of baffle  50  and body casing  20 . 
     Referring now to  FIGS. 6 ,  7  and  8 , threaded opening  114  of turbine unit  90  is further configured to threadedly receive a shaft portion  132  of mandrel  40 . Mandrel  40  generally comprises a tubular member having a first end  140 , a second end  142  and a fluid pathway  150  extending therebetween. First end  140  comprises an elongate shaft having a set of external threads  144  to threadedly couple threaded opening  114  of turbine unit  90 . Once coupled, fluid pathway  150  and internal lumen  98  are in fluid communication. In some embodiments, an o-ring  110  or other sealing means is interposed between mandrel  40  and turbine unit  90  to contain the flow of drilling fluid to within the internal pathways  26 ,  70 ,  78 ,  52 ,  98  and  150  of the assembly  10 . 
     Second end  142  comprises a stepped base having a set of internal threads  146  to threadedly couple a drill bit  14 . The stepped configuration provides various horizontal surfaces which act to support various components of the assembly  10 , discussed in detail below. 
     With reference to  FIGS. 6 and 8 , the outer diameter of shaft portion  132  is selected to receive a first bearing unit  160 . Bearing unit  160  is provided to permit free rotation of turbine unit  90  and mandrel  40  relative to the stationary positions of body casing  20  (not shown) and bearing housing  30 . Thus, in some embodiments the second end  94  of turbine unit  90  comprises a generally horizontal bearing surface  104  to receive and support bearing unit  160 . 
     Bearing unit  160  may include any combination of bearings, spacers, sealing means, grommets, o-rings, and the like as known and commonly used in the art. In some embodiments, bearing unit  160  comprises a combination of various units including thrust bearings  162 , spacers  164 , and sealed bearings  170 . In other embodiments, bearing unit  160  further comprises a spacer  174  having a plurality of recesses to receive various o-rings, such as a Teflon® o-ring  176  and a rubber o-ring  178 . Thus, the combination of various units provides a bearing unit  160  configured to allow turbine unit  90  and mandrel  40  to freely rotate within the drilling sub assembly  10 . 
     Referring now to  FIGS. 6-9 , bearing housing  30  generally comprises a tubular member having an inner diameter  32  configured to rotatably receive shaft  132  of mandrel  40 . A first end  34  of bearing housing  30  comprises a set of threads for threadedly coupling the second end  24  of body casing  20 . The inner lumen of bearing housing  30  further includes an upper bearing surface  176  and a lower bearing surface  178  configured to support both the first bearing unit  160  and a second bearing unit  180 , respectively. In some embodiments, the second bearing unit  180  comprises a combination of various bearing units, similar to those described in connection with the first bearing unit  160 , above. The second bearing unit  180  is seated over shaft  132  of mandrel  40  such that the second bearing unit  180  is interposed between bearing surface  136  of mandrel  40  and lower bearing surface  178  of bearing housing  30 . 
     The first and second bearing units  160  and  180  are selectively set to a desired thrust load by threadedly coupling, to a desired torque, the turbine unit  90  and the mandrel  40 . One of skill in the art will appreciate that variations in the size, type and configuration of the bearing units will necessarily alter the required thrust load. In some embodiments, the desired thrust load of the bearing units is maintained by locking the threaded relationship between the turbine unit  90  and the mandrel  40  via a thread-lock material. In other embodiments, the threaded relationship between the turbine unit  90  and the mandrel  40  is maintained via a tack weld or a set screw (not shown). 
     The bearing unit  112  interposed between the turbine unit  90  and baffle  50  is set to a desired thrust load by threadedly coupling, to a desired torque, the bearing housing  30  and the body casing  20 . Thus, the first and second bearing units  160  and  180 , and bearing unit  112  are capable of being independently adjusted to desired thrust loads, as may be required by the individual bearing unit configurations. 
     In some embodiments, bearing housing  30  further comprises a valve  36 . Valve  36  is generally provided as a means for accessing the first and second bearing units  160  and  180  following assembly of the drilling sub device  10 . In some embodiments, valve  36  comprises a grease port whereby a lubricant is injected into the bearing housing  30  via valve  36 . Thus, valve  36  provides a means whereby the first and second bearing units  160  and  180  are capable of being repacked with a lubricant following use of the assembly  10 . In some embodiments, bearing housing  30  further comprises a second valve (not shown) to permit exchange of spent lubricant within the housing  30  during the process of injecting new lubricant via valve  36 . 
     Referring generally to the various Figures discussed above, of particular interest to the present invention is the lack of gears or other means for controlling the direction and/or speed of turbine unit  90 . In some embodiments of the present invention, the rate of rotation for the turbine unit  90  is directly proportional to the flow rate of drilling fluid through the drilling sub assembly  10 . Thus, the speed of the turbine unit  90  may be variably adjusted by increasing or decreasing the flow rate of the drilling fluid. In some embodiments, the flow rate of the drilling fluid is controlled by adjusting a pump or flow regulator associated with the drilling fluid. In other embodiments, the flow rate of the drilling fluid is adjusted by modifying the features of baffle  50 . 
     For example, in some embodiments baffle  50  is modified to include an increased number of windows  78  and fluid channels  52 , thereby increasing the flow rate of the drilling fluid through the drilling sub assembly  10 . In other embodiments, baffle  50  is modified to include fewer windows  78  and fluid channels  52 , thereby decreasing the flow rate of the drilling fluid through the drilling sub assembly  10 . In some embodiments, the dimensions of fluid channels  52  are modified to increase or decrease the flow rate of the drilling fluid through the baffle  50 . Finally, in some embodiments fluid channel  52  is tapered to accelerate the flow rate of the drilling fluid as it exits baffle  50 . 
     The absence of gears within the present invention eliminates the possibility of damage to the drilling sub assembly  10  in the event of an internal or external jam. For example, should the turbine unit  90  jam due to the presence of debris within the drilling fluid, the turbine unit  90  would simply cease to rotate. The drilling fluid would continue to bypass the turbine unit  90  until either the debris was dislodged by the drilling fluid, or the jam was physically removed. Similarly, in the event of the drill bit  14  becoming jammed, the turbine unit  90 , the mandrel  40  and the drill bit  14  would simply cease rotating. Accordingly, an operator would back the drill bit  14  away from the jam thereby permitting the turbine unit  90 , the mandrel  40  and the drill bit  14  to recover their rotation. The operator would then resume the drilling operation. 
     The drilling sub assembly  10  of the present invention is generally assembled by first positioning baffle  50  within body casing  20 . In some embodiments, o-ring  110  is first within internal lumen  26  so as to be interposed between baffle  50  and the abutting surface of the body casing  20 . Once in place, baffle  50  is secured via set screw  100  thereby preventing further movement or rotation of baffle  50 . 
     Prior to coupling the body casing  20  to the bearing housing  30 , the turbine unit  90 , the bearing housing  30 , the bearing units  160  and  180 , and the mandrel  40  are preassembled, as shown in  FIG. 8 . In particular, the second bearing unit  180  is first placed on bearing surface  136  of the mandrel  40 . Mandrel  40  and bearing unit  180  are then inserted into bearing unit  30  such that bearing unit  180  is seated against lower bearing surface  178 . First bearing unit  160  is then placed over shaft  132  of mandrel  40  such that bearing unit  160  is seated against upper bearing surface  176 . Mandrel  40  is then threadedly coupled to turbine unit  90 , such that o-ring  110  is interposed between threaded opening  114  and first end  140  of mandrel  40 . The mandrel  40  and turbine unit  90  are threadedly coupled to a desired torque so as to achieve a desired thrust load for the first and second bearing units  160  and  180 . 
     The final step in assembly is to threadedly couple the bearing housing  30  to the body casing  20 . Bearing unit  112  is first positioned on the first end  92  of turbine unit  90 . Turbine unit  90  is then inserted into the internal lumen  26  of the body casing  20 . Bearing housing  30  is then threadedly coupled to body casing  20  until bearing unit  112  is seated in within lower chamber  72  of baffle  50 . Bearing housing  30  and body casing  20  are threadedly coupled to a desired torque so as to achieve a desired thrust load for bearing unit  112 . 
     The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. Thus, the described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.