With Means Providing Pressurized Gas Contact With Drilling Liquid Patents (Class 175/205)
  • Patent number: 10167701
    Abstract: An injection valve assembly for use in a well, where pressurized gas or fluid from uphole in the well displaces a perforated valve head from a valve seat, allows for fluid flow of the pressurized gas or fluid into the valve head and further downhole in the well toward an electric submersible pump. A compression spring is coiled around a valve stem connected to the valve head, pushing the valve stem and valve head in an uphole direction opposite to the force from pressurized gas or fluid. The compression spring is in a chamber filled with hydraulic fluid, where the hydraulic fluid can pass through a dampening system assembly and a flow restrictor assembly, thereby regulating the speed at which the valve stem and valve head can move relative to the valve seat.
    Type: Grant
    Filed: October 16, 2017
    Date of Patent: January 1, 2019
    Assignee: Halliburton Energy Services, Inc.
    Inventor: Jimmie Robert Williamson, Jr.
  • Patent number: 10017995
    Abstract: Methods and systems for penetrating a subsurface formation are disclosed. An exemplary apparatus includes a kicker configured to direct a drilling apparatus towards a well casing and a flexible hose configured to convey a fluid from a surface pump to the drilling apparatus. The drilling apparatus includes a drill bit configured to penetrate a well casing and a subsurface formation, and wherein the drilling apparatus is configured to pull the flexible hose into the subsurface formation as the drilling apparatus penetrates the subsurface formation.
    Type: Grant
    Filed: June 12, 2013
    Date of Patent: July 10, 2018
    Assignee: ExxonMobil Upstream Research Company
    Inventor: Matthew A. Dawson
  • Patent number: 9970245
    Abstract: A ground drill system 10 has a drill string 14 which forms first and second mutually isolated fluid paths 16 and 18 respectively. The drill string 14 has an up hole end 20 coupled to a dual circulation rotation head 22 and a down hole end 24 which is coupled to a drilling tool 12. The drilling tool 12 is operated by the flow of fluid delivered through the first flow path 16. A second fluid outlet 26 is provided intermediate the up hole end 20 and the drilling tool 12. The outlet 26 is in fluid communication with the second fluid flow path 18 and located a constant or fixed distance from the drilling toll 12. The second fluid outlet 26 discharges a flushing fluid flowing through the flushing flow path 18 into a hole being drilled by the drilling system 10. The rotation head 22 provides torque to the drill string 14 and thus the drilling tool 12.
    Type: Grant
    Filed: December 21, 2015
    Date of Patent: May 15, 2018
    Assignee: Strada Design Limited
    Inventors: Ian Speer, Warren Strange
  • Patent number: 9708855
    Abstract: A drilling machine includes a compressor coupled to a prime mover through a hydraulic clutch, wherein the hydraulic clutch is repeatably moveable between engaged and disengaged conditions. The compressor is allowed to provide air and is restricted from providing air in response to the hydraulic clutch being in the engaged and disengaged conditions, respectively. The hydraulic clutch is moveable between the engaged and disengaged conditions during operation of the prime mover.
    Type: Grant
    Filed: February 10, 2014
    Date of Patent: July 18, 2017
    Assignee: Allas Copco Drilling Solutions, LLC
    Inventors: Timothy Ledbetter, Iain A. Peebles
  • Patent number: 8857540
    Abstract: An apparatus for releasing gas pressure from a drill string includes a tubular housing having a circumferential sidewall, an axis, a first end, a second end and a central passage extending between the first end and the second end. A pressure member is positioned in the central passage along the axis of the housing. The pressure member is movable from a first position retracted within the housing to a second position extending past the second end of the housing. An actuator is provided to move the pressure member from the first position to the second position, where the pressure member exerts a force to move a valve member of a float valve to an open position, thereby allowing gas trapped in the drill string to flow through the central passage.
    Type: Grant
    Filed: January 26, 2012
    Date of Patent: October 14, 2014
    Inventor: Adam Paul Blake
  • Patent number: 8646549
    Abstract: A drilling machine includes a compressor coupled to a prime mover through a hydraulic clutch, wherein the hydraulic clutch is repeatably moveable between engaged and disengaged conditions. The compressor is allowed to provide air and is restricted from providing air in response to the hydraulic clutch being in the engaged and disengaged conditions, respectively. The hydraulic clutch is moveable between the engaged and disengaged conditions during operation of the prime mover.
    Type: Grant
    Filed: October 8, 2009
    Date of Patent: February 11, 2014
    Assignee: Atlas Copco Drilling Solutions LLC
    Inventors: Timothy W. Ledbetter, Iain A. Peebles
  • Patent number: 8517122
    Abstract: A drill and a separator apparatus and a method of prolonging bearing life are described, the separator apparatus being suitable for separating an air/water mixture into discrete air and water streams during drilling of a blast hole. The separator apparatus includes a separator body which is adapted to be installed at a distal or lower region of a drill string and when installed at the distal or lower region forms one or more separation chambers or reservoirs, each separation chamber or reservoir comprising an inlet adapted to receive the air/water mixture, a first outlet in fluid communication with a drill bit for releasing air thereto and a second outlet in fluid communication with a wall of the blast hole and disposed in the distal or lower region of the drill string to release water separated from the air/water mixture in a region adjacent the drill bit.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: August 27, 2013
    Assignee: Cardinal Trading Company Pty Ltd.
    Inventor: Jacob Garth Lowry
  • Patent number: 8459376
    Abstract: A system for drilling a well bore with an under-balanced hydrostatic pressure. The system includes a tubular member containing a first port, a compression member disposed about the outer portion of the tubular member and having an internal sliding mandrel extending therefrom with a second port, an external sliding sleeve having a third port and being in contact with the internal sliding mandrel and operatively associated with the internal sliding mandrel, and a compressible seal disposed about the external sliding mandrel that is responsive to a longitudinal weight transferred to the compression member. In a closed position the first, second and third port are misaligned and in an open position the first, second and third ports are aligned.
    Type: Grant
    Filed: December 29, 2010
    Date of Patent: June 11, 2013
    Inventor: Danny T. Williams
  • Patent number: 8371399
    Abstract: According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: February 12, 2013
    Assignee: Vitruvian Exploration, LLC
    Inventor: Joseph Alan Zupanick
  • Patent number: 8316966
    Abstract: According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: November 27, 2012
    Assignee: Vitruvian Exploration, LLC
    Inventor: Joseph A. Zupanick
  • Patent number: 8272456
    Abstract: A system for drilling a well having a wellbore includes a first pipe string positioned in the wellbore with a first annulus being present between the first pipe string and the wellbore. A second pipe string, smaller in diameter than the first pipe string, is positioned within the first pipe string to form a second annulus between the first pipe string and the second pipe string. The second pipe string is configured to be attached to a drill bit. A first rotator is operably associated with the first pipe string to rotate the first pipe string in a first direction at a first speed, and a second rotator is operably associated with the second pipe string to rotate the second pipe string in a second direction at a second speed.
    Type: Grant
    Filed: December 31, 2008
    Date of Patent: September 25, 2012
    Assignee: Pine Trees Gas, LLC
    Inventor: Joseph A. Zupanick
  • Patent number: 8127866
    Abstract: The present invention is an air injection collar for use in the drilling industry that is used to reduce the weight of the column of returning drilling mud and debris without causing unnecessary frictional wear on the drill pipe. The invention is a unique sleeve that is coupled to a drill casing that includes an input port for receiving the pressurized air or other fluid from the surface, an annular plenum extending around the drill casing, and a series of openings in the plenum leading to the inside of the drill casing. These openings disperse the pressurized air or other fluid into the upflowing mud around the central drill pipe so that it is not concentrated in one place, especially the center of the casing, where it could cause frictional damage to the drill pipe.
    Type: Grant
    Filed: April 10, 2009
    Date of Patent: March 6, 2012
    Inventor: Paul G. Anthony
  • Patent number: 7886849
    Abstract: A system and method for drilling a well bore with an under-balanced hydrostatic pressure. The system used in the method includes a tubular member containing a first port, a compression member disposed about the outer portion of the tubular member and having an internal sliding mandrel extending therefrom with a second port, an external sliding sleeve having a third port and being in contact with the internal sliding mandrel and operatively associated with the internal sliding mandrel, and a compressible seal disposed about the external sliding mandrel that is responsive to a longitudinal weight transferred to the compression member. In a closed position the first, second and third port are misaligned and in an open position the first, second and third ports are aligned.
    Type: Grant
    Filed: February 11, 2008
    Date of Patent: February 15, 2011
    Inventor: Danny T. Williams
  • Publication number: 20090205872
    Abstract: The present invention is an air injection collar for use in the drilling industry that is used to reduce the weight of the column of returning drilling mud and debris without causing unnecessary frictional wear on the drill pipe. The invention is a unique sleeve that is coupled to a drill casing that includes an input port for receiving the pressurized air or other fluid from the surface, an annular plenum extending around the drill casing, and a series of openings in the plenum leading to the inside of the drill casing. These openings disperse the pressurized air or other fluid into the upflowing mud around the central drill pipe so that it is not concentrated in one place, especially the center of the casing, where it could cause frictional damage to the drill pipe.
    Type: Application
    Filed: April 10, 2009
    Publication date: August 20, 2009
    Inventor: Paul G. Anthony
  • Publication number: 20090200085
    Abstract: A system and method for drilling a well bore with an under-balanced hydrostatic pressure. The system comprises a tubular containing a first port and wherein a well bore annulus is formed between the well bore and the tubular member, and a compression member disposed about the outer portion of the tubular member, the compression member having extending therefrom an internal sliding mandrel, and wherein the internal sliding mandrel contains a second port. The system further comprises an external sliding sleeve operatively associated with the internal sliding mandrel, wherein the external sliding sleeve containing a third port, and wherein in a closed position the first, second and third port are misaligned and in an open position the first, second and third port are aligned. The system also includes a compressible seal disposed about the external sliding sleeve and in contact with the internal sliding mandrel, the compressible seal responsive to a longitudinal weight transferred to the compression member.
    Type: Application
    Filed: February 11, 2008
    Publication date: August 13, 2009
    Inventor: Danny T. Williams
  • Patent number: 7516803
    Abstract: The present invention is an air injection collar for use in the drilling industry that is used to reduce the weight of the column of returning drilling mud and debris without causing unnecessary frictional wear on the drill pipe. The invention is a unique sleeve that is coupled to a drill casing that includes an input port for receiving the pressurized air or other fluid from the surface, an annular plenum extending around the drill casing, and a series of openings in the plenum leading to the inside of the drill casing. These openings disperse the pressurized air or other fluid into the upflowing mud around the central drill pipe so that it is not concentrated in one place, especially the center of the casing, where it could cause frictional damage to the drill pipe.
    Type: Grant
    Filed: February 10, 2006
    Date of Patent: April 14, 2009
    Inventor: Paul G Anthony
  • Publication number: 20090020336
    Abstract: A system for facilitating flow of settled solids with drilling fluid from a container, the system including pressure nozzle apparatus with at least one nozzle from which is flowable fluid under pressure, powered rotation apparatus for selectively rotating the pressure nozzle apparatus so that the at least one nozzle is movable within the container as fluid is pumped through the at least one nozzle into the container; and, in one aspect, translation apparatus for moving the pressure nozzle apparatus with respect to the container as fluid under pressure is pumped to the at least one rotating nozzle.
    Type: Application
    Filed: September 17, 2008
    Publication date: January 22, 2009
    Inventors: Clyde Bohnsack, Guy L. McClung, III
  • Patent number: 7325629
    Abstract: A method for integrating a batch cement process with a cuttings reinjection process, the method comprising: equipping a batch cement skid with a particle classifier and a grinding pump, such that the batch cement skid sequentially implements the cuttings reinjection process and the batch cement process is disclosed. An apparatus for performing a batch cement process and a cuttings reinjection process, the apparatus comprising: a first tank and a second tank, a particle classifier having a coarse effluent stream feeding into the first tank and a fine effluent stream feeding into the second tank, and a grinding pump in fluid communication with the first tank and the particle classifier is also disclosed.
    Type: Grant
    Filed: September 8, 2005
    Date of Patent: February 5, 2008
    Assignee: Halliburton Energy Services, Inc.
    Inventors: Keith Edward Blaschke, Kevin Michael Stewart, Bryan Clint Walker, Timothy Neal Harvey, Danny Keith Mints
  • Patent number: 7111695
    Abstract: The invention relates to a method for horizontal ground drilling, in particular for rock drilling, by means of a ground drilling apparatus which can be driven forward in rotation and percussively, the apparatus having compressed air and drilling medium applied to it alternately or simultaneously, and the compressed air and the drilling medium being supplied via one channel.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: September 26, 2006
    Assignee: Tracto-Technik GmbH
    Inventor: Franz-Josef Puttmann
  • Patent number: 7093662
    Abstract: A system for controlling drilling mud density at a location either at the seabed (or just above the seabed) or alternatively below the seabed of wells in offshore and land-based drilling applications is disclosed. The present invention combines a base fluid of lesser/greater density than the drilling fluid required at the drill bit to drill the well to produce a combination return mud in the riser. By combining the appropriate quantities of drilling mud with a light fluid, a riser mud density at or near the density of seawater may be achieved to facilitate transporting the return mud to the surface. Alternatively, by injecting the appropriate quantities of heavy fluid into a light return mud, the column of return mud may be sufficiently weighted to protect the wellhead. At the surface, the combination return mud is passed through a treatment system to cleanse the mud of drill cuttings and to separate the drilling fluid from the base fluid.
    Type: Grant
    Filed: October 29, 2003
    Date of Patent: August 22, 2006
    Inventor: Luc deBoer
  • Patent number: 7059426
    Abstract: An underground drilling method and apparatus generates intense pressure pulses at a location at the surface. The pressure pulses propagate down through a drill string to a drill bit. The pulses may be generated by creating water hammer in flowing drilling mud. Intensity of the acoustic pulses is increased in the bit nozzles. Vigorous pulsing of the fluid exiting the bit nozzles results in better cleaning of the hole bottom and faster drilling. The pulses may be used to drive the operation of various down hole tools. One type of tool has multiple pistons arranged in series. High pressure pulses move the pistons to generate strong mechanical vibration in the drill string. Vibration of the drill string may also reduce the friction between the drill string and the hole, resulting in lower torque requirements.
    Type: Grant
    Filed: June 13, 2005
    Date of Patent: June 13, 2006
    Assignee: Lewal Drilling Ltd.
    Inventor: Bruno Walter
  • Patent number: 7025154
    Abstract: A method for circulating drilling fluid in a well system includes drilling a substantially vertical well bore from a surface to a subterranean zone and drilling an articulated well bore from the surface to the subterranean zone. The articulated well bore is horizontally offset from the substantially vertical well bore at the surface and intersects the substantially vertical well bore at a junction proximate the subterranean zone. The method includes drilling a drainage bore from the junction into the subterranean zone and pumping a drilling fluid through the drill string when drilling the drainage bore. The method also includes providing fluid down the substantially vertical well bore through a tubing. A fluid mixture returns up the substantially vertical well bore outside of the tubing. The fluid mixture comprises the drilling fluid after the drilling fluid exits the drill string.
    Type: Grant
    Filed: December 18, 2002
    Date of Patent: April 11, 2006
    Assignee: CDX Gas, LLC
    Inventor: Joseph A. Zupanick
  • Publication number: 20040195008
    Abstract: A drill bit shaft member for tapping a hole in a blast furnace is disclosed. The drill bit shaft member comprises an elongate rod, a first fluid pressure inlet, a second fluid pressure inlet, a chamber in fluid communication with the first fluid pressure inlet and the second fluid pressure inlet, and an outlet in fluid communication with the chamber. A liquid and a gas are combined in the drill bit shaft member to form a mist to provide cooling for the drill bit shaft member. By cooling the drill bit shaft member, certain components that would normally be destroyed may be re-used.
    Type: Application
    Filed: March 3, 2004
    Publication date: October 7, 2004
    Inventor: Gilbert R. Broom
  • Publication number: 20040074673
    Abstract: Disclosed is an apparatus for producing a pressurized stream of substantially inert gas. The apparatus includes a compressor having an intake manifold and an output manifold. The intake manifold receives a substantially inert gas stream and the output manifold receives a stream of pressurized gas from the compressor. The apparatus further includes a compressed gas re-circulation conduit connecting the output manifold to the intake manifold such that a portion of the pressurized gas from the compressor is re-circulated from the output manifold back to the intake manifold to maintain the gas pressure within the intake manifold above atmospheric pressure and to prevent atmospheric gases from being drawn into the intake manifold.
    Type: Application
    Filed: July 28, 2003
    Publication date: April 22, 2004
    Inventor: Ross Michael Krill
  • Patent number: 6588501
    Abstract: A pumping system for injecting buoyant spheres into an oil or gas well having a feeder containing a plurality of buoyant spheres; and a sphere pump in proximity to the feeder, having first and second rotatable wheels, wherein the first wheel has a plurality of notches and the second wheel has a corresponding plurality of notches, such that during rotation of the wheels the first and second wheel notches temporarily combine to form a plurality of pockets, wherein each pocket receives then ejects one of the plurality of buoyant spheres from the feeder during rotation of the first and second wheels.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: July 8, 2003
    Assignee: Varco I/P, Inc.
    Inventor: George Boyadjieff
  • Patent number: 6347675
    Abstract: A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC—CO2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC—CO2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC—CO2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC—CO2 much more effective than water jet erosion.
    Type: Grant
    Filed: March 9, 2000
    Date of Patent: February 19, 2002
    Assignee: Tempress Technologies, Inc.
    Inventor: Jack J. Kollé
  • Patent number: 6032747
    Abstract: A method and an apparatus is provided for use in an underbalanced drilling process using exhaust gases wherein some constituents of the exhaust gas combine with water to form acids. The present invention provides a means of deacidifying drilling fluids. The pH of the drilling fluid is monitored and adjusted to prevent corrosion of equipment by acidic drilling fluids. The drilling fluid may also be optionally treated with anti-scaling agents. The drilling fluid may be a gas, a liquid or a combination of both or it may be gasified oil based drilling fluid.
    Type: Grant
    Filed: June 10, 1998
    Date of Patent: March 7, 2000
    Assignee: Underbalanced Drilling Systems Limited
    Inventors: Eugene I. Moody, Donald A. Thorssen
  • Patent number: 5950736
    Abstract: A drilling apparatus includes a drill string, a drilling head located at a first end of the drill string, a drilling fluid pump located at a second end of the drill string, wherein the drilling fluid pump pumps a drilling fluid along the length of the drill string to the drilling head, and a traveling wave generator coupled to the drill string at a location downstream of the drilling fluid pump, wherein the traveling wave generator generates a series of ramped pressure pulses that are applied to the drilling fluid. The ramped pressure pulses are compressed by a reduction of the cross-sectional area of the drill string, and further by time compression caused by varying propagation rates of different portions of the pressure pulses pressure pulse if substantially formed at a surface of a drilling substrate. A shock wave associated with the compressed pressure pulse is generated substantially at the location of a surface of a drilling substrate.
    Type: Grant
    Filed: September 26, 1997
    Date of Patent: September 14, 1999
    Assignee: APTI Inc.
    Inventor: Yeshayahu S. Goldstein
  • Patent number: 5865261
    Abstract: A casing or tubing segment or segments are disclosed which can be used to create a parasite annulus during drilling. The cased wellbore receives a string containing valves and the drillstring operates through it. As the mud circulates, the segments of the tubing or casing provide communication at various depths from the parasite annulus (i.e., the outermost annulus) into the circulating mud, which is the innermost annulus. Each valve is adjustable to alter the amount of differential pressure required in order to open it. The valves are also in hydraulic pressure balance so that only the pressure added by the injected gas acts to open them. The valves close by a spring bias.
    Type: Grant
    Filed: March 3, 1997
    Date of Patent: February 2, 1999
    Assignee: Baker Hughes Incorporated
    Inventors: Gary E. Cooper, Alex Crabtree, David Cameron
  • Patent number: 5427190
    Abstract: In an underground borer with down hammer having a vehicle body 1, a guide stilt 2 standing on the vehicle body, and a rotary machine 4 having its bottom coupled with a screw shaft 3 and a down hammer B, a supply unit 5 is interposed between the rotary machine 4 and the screw shaft 3, a fluid conduit 6 is formed centrally of the screw shaft 3, compressed air conduits 7 and 7' are formed to surround the fluid conduit 6, and a fluid jetting pipe 8 is arranged centrally of the down hammer B to extend until the inside of a bit body 9 so that water may be discharged, along with high-pressure compressed air, from a central portion of the bottom surface of the bit body during boring to cool the bit body, promote anti-wear properties, suppress powdery dirts, reduce noises and increase the boring speed.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: June 27, 1995
    Assignees: Kencho Kobe Co., Ltd., Jeon Jin Mo
    Inventor: Jeon J. Mo
  • Patent number: 5330017
    Abstract: A method and associated apparatus are provided for processing the drilling mud used to flush cuttings from the bore hole while maintaining control of bore hole pressure. Air is injected into the lower regions of drilling mud in the working pits to agitate the drilling fluids and thus maintain particulate additives in suspension while simultaneously facilitating the settling of larger cuttings from the earth formations. Air is also injected into the bottom of the drilling mud and other waste fluids which are placed into the discard pit to evaporate the water and thereby accelerate consolidation or ultimate drying of the drilling mud for final disposal. This can be done as required during the drilling operation so that the consolidated or dried drilling mud can then be more easily and economically handled for transport to a hazardous waste disposal site, or can be more easily covered with earth while remaining in the discard pit.
    Type: Grant
    Filed: April 6, 1992
    Date of Patent: July 19, 1994
    Assignee: Profit Production, Inc.
    Inventors: Thomas H. Hart, Jimmy G. Reid
  • Patent number: 4474252
    Abstract: Means are provided to drill generally horizontal bores through heterogeneous fill and hard strata. A carriage providing power means to rotate a spindle is mounted on a generally horizontal track and is adapted to move longitudinally along the track. Swivel means about the spindle are provided with means to introduce a combined gas and liquid stream, suitably air and water, into a drill pipe connected to the spindle and through an impact drill mounted at the end of the drill pipe to power the drill and to flush cuttings from the hole.
    Type: Grant
    Filed: May 24, 1983
    Date of Patent: October 2, 1984
    Inventor: Farish R. Thompson
  • Patent number: 4194567
    Abstract: The invention relates to the balancing of the pressures in drilled strata, the pressures being lower than that of the liquid columns contained in the entire well.The hydrostatic level of fluid, e.g. a liquid, in the bottom of the well is selected to obtain the balance and the fluid is caused to flow, to additionally serve as a drilling fluid, by separating the fluid into two columns, communicating at either end, between the tubing of the well and a set of rods therein and within the set of rods, and injecting a fluid of lower density into the upper part of one of the columns.
    Type: Grant
    Filed: October 26, 1978
    Date of Patent: March 25, 1980
    Assignee: Compagnie Francaise des Petroles
    Inventor: Lionel R. Marais
  • Patent number: 3958650
    Abstract: A drill system for drilling very large holes in the earth, of diameters up to from 10 to 20 feet, by means of a rotary bit carrying a plurality of cutters, wherein the bit assembly is pressed against the bottom of the hole, so that the unit pressure against each of the cutters will be adequate for their optimum performance. The force holding the bit in contact with the bottom of the hole is created by the weight of the drilling liquid on top of the bit. A fluid seal is maintained between the outer edge of the bit and the wall of the bore hole. Liquid flows down the annulus around the drill pipe and through a plurality of orifices in the bit, terminating at the bit cutters. Rock cuttings are washed radially inwardly to a central drill pipe, which supports the bit, and through which torque is applied to the bit. The pressure drop in the orifices serves to create a differential pressure above and below the bit. The differential pressure times the exposed surface area of the bit provides the hold down force.
    Type: Grant
    Filed: May 28, 1975
    Date of Patent: May 25, 1976
    Assignee: The United States of America as represented by the Secretary of the Interior
    Inventors: James H. Cobbs, Roger J. Morrell