Downhole Coupling Or Connector Patents (Class 166/242.6)
  • Patent number: 6408946
    Abstract: An apparatus for disconnecting a bottom hole assembly from a work string, having an upper tool body, a piston biased away from a slidable collet, locking dogs held in engagement with a lower tool body by the slidable collet, and one or more collet fingers holding the collet in place, relative to the upper body. The piston can be hydraulically displaced against the biasing spring, thereby releasing the collet finger, followed by further displacement of the piston to contact the collet, then displacement of the piston and the collet to release the locking dogs from engagement with the lower tool body. A shear pin in the collet can provide a positive pressure indication of release of the disconnect device.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: June 25, 2002
    Assignee: Baker Hughes Incorporated
    Inventors: Gregory S. Marshall, Daniel R. Hart
  • Publication number: 20020074130
    Abstract: An apparatus for radially expanding a tubular member.
    Type: Application
    Filed: February 20, 2002
    Publication date: June 20, 2002
    Applicant: Shell Oil Co.
    Inventors: Robert Lance Cook, David Paul Brisco, Lev Ring, Michael Bullock
  • Publication number: 20020070032
    Abstract: The present invention generally provides a running tool comprising a torque-dampening system. A first portion and a second portion of the running tool are operably related by a torsion interface. In one embodiment, the torsion interface includes a plurality of interlaced teeth disposed on the each of the first and second portions. During relative rotation of the first and second portions, the teeth engage and “ride up” on one another, thereby forcing the first and second portions in opposite axial directions. At least one of the portions houses a flow restrictor assembly adapted to restrict fluid flow from one region to another during the axial movement of the portions. Accordingly, the relative rotation between the portions is inhibited, or dampened.
    Type: Application
    Filed: December 11, 2000
    Publication date: June 13, 2002
    Inventors: Patrick G. Maguire, Richard Duff, Tarald Gudmestad, Mark Murray
  • Patent number: 6382324
    Abstract: A system for permitting deployment of a polished bore receptacle, seal stack and production tubing in a single downhole trip into a wellbore. The system includes a polished bore receptacle, production tubing, a seal stack disposed about the production tubing, and a one trip seal latch that couples the production tubing to the polished bore receptacle. The seal latch includes an outer latch housing and an inner latch housing. The outer housing and inner housing are connected by a releasable coupling device. Thus, the polished bore receptacle can be moved downhole for latching to a packer without insertion of the seal stack into the interior of the polished bore receptacle. Upon latching of the polished bore receptacle to the packer, the coupler may be selectively released to permit insertion of the seal stack into the polished bore receptacle.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: May 7, 2002
    Assignee: Schlumberger Technology Corp.
    Inventor: Steven L. Anyan
  • Publication number: 20020046834
    Abstract: The present invention provides a hydraulic actuator adapted for use in downhole well applications that enables control of several hydraulic devices from a single control line.
    Type: Application
    Filed: February 7, 2001
    Publication date: April 25, 2002
    Inventors: Christophe M. Rayssiguier, Vong Vongphakdy
  • Patent number: 6352107
    Abstract: An elongated pump rod or sinkerbar for use in a pump rod string for a downhole reciprocating well pump is provided with an elongated sleeve of high density or ultra high density polyethylene over a major portion of the length of the sinkerbar to minimize wear on the sinkerbar and a well tubing string as a consequence of deflection of the sinkerbar into engagement width the tubing string and to minimize frictional drag on the pump actuating mechanism as a result of such engagement. The polyethylene sleeve may be assembled over the sinkerbar by apparatus including an elongated hydraulic actuator which may be configured to push a sinkerbar into the sleeve while the sleeve is held stationary within a support tube, or by holding the sinkerbar stationary on a support and pulling the sleeve over the sinkerbar and from a continuous length of tubing from which the sleeve is formed.
    Type: Grant
    Filed: February 11, 1999
    Date of Patent: March 5, 2002
    Assignee: Allen & Bennett, Inc.
    Inventors: Donald W. Bennett, Johnny B. Fayo, Scott W. Long
  • Patent number: 6349767
    Abstract: A disconnect tool includes a housing that has a first segment and a second segment. A first collet is coupled to the first segment and has a first plurality of fingers, each of the first plurality of fingers is bendable between a first position in which the fingers engage the first segment and prevent relative sliding movement between the first and second segments, and a second position in which the fingers do not engage the first segment and do not prevent relative sliding movement between the first and second segments. A first piston is positioned in the housing and has a third position wherein the piston engages and prevents the fingers from bending from the first position, and a fourth position wherein the piston does not engage and prevent the fingers from bending from the first position. The disconnect tool includes means for selectively retaining the first piston in the third position and means for moving the first piston from the third position to the fourth position.
    Type: Grant
    Filed: May 13, 1998
    Date of Patent: February 26, 2002
    Assignee: Halliburton Energy Services, Inc.
    Inventor: Robert W. Gissler
  • Publication number: 20020014336
    Abstract: An underwater or severe environment electrical connector, comprising first and second connector parts which are to be brought together in longitudinal alignment to establish electrical contact between respective contact portions of the first and second connector parts, the connector parts being relatively rotatable about a longitudinal axis when the connector parts are disconnected, and the contact portions being laterally spaced from said longitudinal axis and being arranged to make said electrical contact when the connector parts are connected, irrespective of the relative rotational positions of the first and second connector parts about said longitudinal axis.
    Type: Application
    Filed: July 5, 2001
    Publication date: February 7, 2002
    Inventor: Mark R. Jones
  • Publication number: 20020005282
    Abstract: The subsurface signal transmitting apparatus (10) including an insulation coupler (11), a carrier device (12) for mounting the telemetry instrumentation (75), and a by-pass system for avoiding pressure build-up either above or below the apparatus. The insulation coupler (11) includes a housing member (13) having a central opening (16) defined by an interior surface (22) extending in the longitudinal direction and a mandrel member (14) having an exterior surface (32) spaced from the interior surface (22) of the housing member (13) to provide a gap or clearance (33) with an insulating bonding material (29) occupying the clearance.
    Type: Application
    Filed: February 5, 2001
    Publication date: January 17, 2002
    Applicant: Weatherford/Lamb, Inc.
    Inventors: Marvin L. Holbert, James W. Haslett, Robert E. Smallwood, Frederick N. Trofimenkoff
  • Publication number: 20020000317
    Abstract: A downhole string includes a liner and devices positioned outside the liner. One or more control lines extend from the liner devices along the exterior of the liner to one or more connectors that provide connection points inside the liner. The one or more connectors may include electrical connectors (e.g., direct contact connectors), inductive connectors (e.g., inductive couplers), optical connectors (e.g., fiber optic connectors), and hydraulic connectors. The one or more control lines may be electrical lines, fiber optic lines, or hydraulic lines. The downhole string may also be used with a cement protector during cementing operations to protect both the inside of the liner as well as the one or more connectors attached to the liner. The cement protector includes a sleeve that isolates cement from the inside of the liner during a cementing operation so that a liner wiper plug is not needed. The cement protector is engageable to a pulling tool that is attached to a running tool.
    Type: Application
    Filed: August 22, 2001
    Publication date: January 3, 2002
    Inventors: Christophe M. Rayssiguier, Michael R. Johnson, Ronald E. Pringle, John A. Booker, Alexandre G.E. Kosmala
  • Publication number: 20020000334
    Abstract: A device for connecting a tool to a mechanical drive contains as the coupling element a spring washer coupling or clutch, which is made in one piece from metal and at least in the rotation direction has a limited resilience. Use is made thereof for preventing torque peaks in the case of a sudden deceleration of the tool, e.g. if a screw strikes a wood surface.
    Type: Application
    Filed: May 25, 2001
    Publication date: January 3, 2002
    Inventors: Karl Lieser, Andreas Dierolf, Frank Kollmar
  • Patent number: 6332499
    Abstract: A connector for use in a deployment system able to deploy and power a device, such as an electric submergible pumping system, in a well. The connector includes pluggable ends that permit connection adjacent segments, each having an outer section of tubing and an internal power cable. Each connector includes a tubing connector portion and a power cable connector portion that permit pluggable connection of sequential tubing segments when deploying a device or system downhole.
    Type: Grant
    Filed: November 23, 1999
    Date of Patent: December 25, 2001
    Assignee: Camco International, Inc.
    Inventors: Lee S. Kobylinski, John C. Pursell, Howard A. Oswald, Marcus D. McHugh, Pinke Halpert
  • Publication number: 20010045289
    Abstract: A wellbore casing formed by extruding a tubular liner off of a mandrel. The tubular liner and mandrel are positioned within a new section of a wellbore with the tubular liner in an overlapping relationship with an existing casing. A hardenable fluidic material is injected into the new section of the wellbore below the level of the mandrel and into the annular region between the tubular liner and the new section of the wellbore. The inner and outer regions of the tubular liner are then fluidicly isolated. A non hardenable fluidic material is then injected into a portion of an interior region of the tubular liner to pressurize the portion of the interior region of the tubular liner below the mandrel. The tubular liner is then extruded off of the mandrel.
    Type: Application
    Filed: May 9, 2001
    Publication date: November 29, 2001
    Inventors: Robert Lance Cook, David Paul Brisco, R. Bruce Stewart, Lev Ring, Richard Carl Haut, Robert Donald Mack
  • Publication number: 20010045283
    Abstract: The present invention discloses apparatus and methods that can be used to sever a control line. One embodiment of the invention is a shear sub comprising a first member and a second member that are releasably attached to each other. The first and second members define a control line passageway. The control line passageway comprises a pair of shearing blades that are adapted to shear a control line during release of the first member from the second member.
    Type: Application
    Filed: April 19, 2001
    Publication date: November 29, 2001
    Inventor: Dwayne D. Leismer
  • Publication number: 20010035288
    Abstract: A method and apparatus that allows communications of electrical power and signaling from downhole component to another downhole component employs an inductive coupler assembly. In one arrangement, one portion of the inductive coupler assembly is attached to a production tubing section and the other portion of the inductive coupler assembly is attached to a casing or other liner section. The production tubing inductive coupler portion is electrically connected to a cable over which electrical power and signals may be transmitted. Such power and signals are magnetically coupled to the inductive coupler portion in the casing or liner section and communicated to various electrical devices mounted outside the casing or liner section. In other arrangements, inductive coupler assemblies may be used to couple electrical power and signals from the main bore to components in lateral branches of a multilateral well.
    Type: Application
    Filed: May 17, 2001
    Publication date: November 1, 2001
    Inventors: Mark W. Brockman, Herve Ohmer, David L. Malone
  • Publication number: 20010030048
    Abstract: An Internal Bottom Hole Assembly (IBHA) for a Coiled Tubing (CT) enables the CT to be used with other devices downhole. The IBHA includes a connector, a valve assembly and an emergency disconnect device, all of which are mounted internally in the CT. The connector couples to the inside of the CT by means of wedges that are urged against the inside wall of the CT. The valve assembly may be mounted either between the connector and the disconnect device or may be on the side of the connector away from the disconnect device. The valve assembly includes one or more flapper valves that are able to pass a ball through at a minimum flow rate of fluid, enabling the ball to be used to operate the disconnect device.
    Type: Application
    Filed: May 17, 2001
    Publication date: October 18, 2001
    Inventors: Gordon Mackenzie, Darrin F. Willauer, Martin P. Coronado
  • Publication number: 20010026069
    Abstract: A percussive drilling component includes a cylindrical male screw thread formed of a steel material. The thread includes thread crests and thread roots interconnected by thread flanks. To protect the thread against corrosion, the thread is coated with a material having a higher electrode potential than the steel material. The coating is situated at least in regions located radially inwardly of the thread flanks. The male screw thread can be attached to a female screw thread of another percussive drilling component, the female screw thread also being coated with the material.
    Type: Application
    Filed: March 2, 2001
    Publication date: October 4, 2001
    Inventor: John Linden
  • Patent number: 6276386
    Abstract: There is described herein an apparatus for charging a fluid line through a coupler such as a penetrator. The apparatus comprises a body formed from a sidewall defining a bore positioned along the longitudinal axis and extending therethrough. The first end of the body forms a substantially flat face. There is a stem positioned within the bore of the body and being movably mounted in the body for movement from a first position to a second position with respect to the body. There is a valve means attached to the apparatus for filling the body with hydraulic fluid. The substantially flat face of the body is fastened to a coupler. There is also an adjustment means attached to the stem for adjusting the position of the stem within the body. A method for charging a downhole hydraulic system is also described. There is also a method for installing a tubing hanger having a production string depending therefrom in a subsea wellhead while maintaining a hydraulically actuated downhole valve in an open position.
    Type: Grant
    Filed: November 24, 1997
    Date of Patent: August 21, 2001
    Assignee: Kvaerner Oilfield Products, Inc.
    Inventor: Robert Diedrich Stubbeman
  • Patent number: 6269879
    Abstract: A side entry tool having a lower end portion for receiving a saver sub thereon. There is further provided a sleeve portion positioned in the lower end of the side entry tool having an outside diameter smaller than the inside diameter of the tool body; the sleeve would have undergone heat treatment to a certain rockwell hardness so that because of the smaller diameter of the sleeve, any contact of the wireline with the tool body would make contact with the hardened sleeve, which could take the contact without a groove or cut being formed in the sleeve. The sleeve would be held in place with a set screw at its lower end to prevent it from rotating. In the event the sleeve indicates wireline wear, the set screw would be loosened and the sleeve would be rotated so that the wireline would make contact with a non-affected portion of the sleeve.
    Type: Grant
    Filed: March 20, 2000
    Date of Patent: August 7, 2001
    Inventor: Harper Boyd
  • Publication number: 20010009189
    Abstract: A well has a vertical casing with a window, and a lateral wellbore which communicates with the window, and which may have a casing or liner. A window assembly aligned with the window has respective passageways for first and second tubing strings, and has a concave surface for deflecting the first tubing string out into the lateral wellbore. The passageway for the second tubing string has a portion which is inclined at a very small angle with respect to a vertical centerline of the vertical casing. As the first tubing string is run into the vertical casing, a rotational locator is releasably coupled thereto by a soft release coupling mechanism. After the locator effects rotational orientation, the coupling mechanism is released and then permits the first tubing string to move therepast without damage. A seal assembly on the first tubing string is covered by a protective sleeve as it is inserted into the well, and exits the protective sleeve after entering the lateral wellbore.
    Type: Application
    Filed: January 19, 2001
    Publication date: July 26, 2001
    Applicant: Dresser Industries, Inc.
    Inventors: Robert T. Brooks, David J. Steele, Dan P. Saurer, Larry R. Valentine, Jody R. McGlothen
  • Patent number: 6263983
    Abstract: The invention provides an improved apparatus for directional boring and in particular an improved system for boring through hard and rocky substrates frequently encountered when boring under obstacles such as roadways. According to one aspect of the invention, a directional drilling apparatus includes a drilling head having a front face angled relative to the lengthwise axis of the tool and configured for steering the drilling apparatus, a housing having an internal chamber for mounting an electronic locating device therein rearwardly of the drilling head for transmitting a signal indicating the orientation of the angled face of the drilling head, and a joint at which the drilling head is removably mounted to the housing of the locating device.
    Type: Grant
    Filed: August 12, 1999
    Date of Patent: July 24, 2001
    Assignee: Earth Tool Company, L.L.C.
    Inventors: Steven W. Wentworth, Robert F. Crane
  • Patent number: 6257792
    Abstract: The invention is directed to a retaining ring for securing components along a shaft by transferring the compression load between the components, thereby preventing the adjacent components from separating. The retaining ring includes a pair of arcuate interlocking members having a first end, a second end, an inner wall and an outer wall. The outer wall includes a first surface and the inner wall includes a second surface thereby defining a thickness between the first surface and the second surface. The inner wall also includes a third surface thereby defining a thickness between the third surface and the first surface, wherein the thickness between the third surface and the first surface is less than the thickness between the second surface and the first surface. The inner wall also includes a fourth surface joining the second surface and the third surface to define a smooth transition therebetween.
    Type: Grant
    Filed: March 25, 1999
    Date of Patent: July 10, 2001
    Assignee: Camco International Inc.
    Inventor: Dennis M. Read, Jr.
  • Patent number: 6247537
    Abstract: High pressure fluid seals for sealing against a bit guide in wellhead and a method of using the seals are described. The high pressure fluid seals are primarily intended for use with a blowout preventer protector. The high pressure fluid seals are elastomeric material bonded to an end of a mandrel for insertion into the wellhead. The end of the mandrel includes an annular ridge that protrudes into the elastomeric seal to inhibit the seal from being extruded away from the bore when the elastomeric seal is seated against the bit guide and the bore is subjected to elevated fluid pressures. The advantage is a high pressure fluid seal that ensures packoff against a bit guide even if the bit guide is worn but still serviceable. A further advantage is a more secure seal that improves safety and enables the use of higher pressures during well stimulation.
    Type: Grant
    Filed: April 26, 1999
    Date of Patent: June 19, 2001
    Inventor: L. Murray Dallas
  • Patent number: 6241022
    Abstract: The present invention is a connector which connects a first control line in a downhole well tool to a second control line. The connector may include a main body having a longitudinal bore therethrough, a tubular extension threadably secured within a mounting bore in the well tool, and a metal seal ring disposed between a shoulder on the tubular extension of the main body and having an outer conical surface engaged with a conical surface of the mounting bore. The connector may also include a sealing sleeve having a longitudinal bore including a first conical surface adjacent a first end of the sealing sleeve and a second conical surface adjacent a second end of the sealing sleeve; a first ferrule, a second ferrule, and a third ferrule, each being an annular member having an outer conical surface and disposed within the longitudinal bore of the main body.
    Type: Grant
    Filed: September 27, 1999
    Date of Patent: June 5, 2001
    Assignee: Camco International Inc.
    Inventors: Jason C. Mailand, Thomas M. Deaton
  • Patent number: 6230806
    Abstract: Temporary no-go assemblies for use in locating a downhole tool at a predetermined target depth in a well are disclosed. Certain ones of the assemblies include a no-go sleeve for interfacing with a no-go shoulder in a casing and an actuating system for releasing the assembly from the no-go sleeve. Other ones of the assemblies include a key for engaging a landing nipple in a casing and a key retractor for retracting the key from the nipple. Still other ones of the assemblies include a key for engaging a no-go shoulder in a casing and a key retractor for retracting the key from the no-go shoulder. The assemblies are particularly useful in drilling and completing wells from a floating drilling rig.
    Type: Grant
    Filed: January 24, 2000
    Date of Patent: May 15, 2001
    Assignee: Halliburton Energy Services, Inc.
    Inventor: John C. Gano
  • Patent number: 6213202
    Abstract: A connector permits separation of a submergible pumping system from its deployment system. The connector includes an upper assembly and a lower assembly that are connected by shear screws. A hydraulic separation mechanism is used to shear the shear screws and separate the upper and lower assemblies from a remote location.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: April 10, 2001
    Assignee: Camco International, Inc.
    Inventor: Dennis M. Read, Jr.
  • Patent number: 6209632
    Abstract: A subsurface signal transmitting apparatus including an insulation coupler, a carrier device for mounting the telemetry instrumentation, and a by-pass system for avoiding pressure build-up either above or below the apparatus. The insulation coupler includes a housing member having a central opening defined by an interior surface extending in the longitudinal direction and a mandrel member having an exterior surface spaced from the interior surface of the housing member to provide a gap or clearance with an insulating bonding material occupying the clearance. The surfaces are oriented so that when the coupling is in tension at least a portion of the two surfaces experience interacting forces towards each other in the longitudinal direction of the coupling and in event of failure of the bonding material, the mandrel member is unable to withdraw from the housing member.
    Type: Grant
    Filed: December 10, 1997
    Date of Patent: April 3, 2001
    Inventors: Marvin L. Holbert, James W. Haslett, Robert E. Smallwood, Frederick N. Trofimenkoff
  • Patent number: 6199632
    Abstract: A locator device (50) that is selectively lockable within a nipple profile (40) disposed within a wellbore (32). The locator device (50) comprises a locator key (106) disposed between a housing (104) and a mandrel (102) that is radially extendable through a window (108) of the housing (104). The locator key (106) has an engageable position and a retracted position with respect to nipple profile (40). A support ring (110) is disposed between the housing (104) and the mandrel (102) that maintains the locator key (106) in the engageable position until the support ring (110) is axially displaced relative to the mandrel (102).
    Type: Grant
    Filed: November 23, 1998
    Date of Patent: March 13, 2001
    Assignee: Halliburton Energy Services, Inc.
    Inventor: Perry C. Shy
  • Patent number: 6199633
    Abstract: The present invention provides a method and apparatus for mechanically interconnecting a lateral wellbore liner to a main, or parent, wellbore casing. The present invention further provides a method of wellbore construction for the construction of multiple wellbores which are interconnected downhole to form a manifold of pipelines in a reservoirs of interest. Provision is made for flow controls, sensors, data transmission, power generation, and other operations positioned in the lateral wellbores during the drilling, completion and production phases of such wellbores.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: March 13, 2001
    Inventor: James R. Longbottom
  • Patent number: 6196325
    Abstract: A heavy-duty logging and perforating cablehead for coiled tubing. The cablehead includes an upper and lower housing which are shearably connected by shear pins. An actuating piston is slidably disposed in the housing. When the piston is in a running position, the piston holds a lug in locking engagement with the upper and lower housings such that the shear pins cannot be sheared. When the piston is moved to a releasing position, the lugs are released so that the upper and lower housings may be separated, thereby shearing the shear pins. Actuation of the piston is accomplished by pumping fluid down the coiled tubing and through a flow path in the cablehead and by applying pressure to the piston.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: March 6, 2001
    Assignee: Halliburton Energy Services, Inc.
    Inventors: Michael L. Connell, Robert G. Howard, James C. Tucker
  • Patent number: 6193474
    Abstract: A well pump assembly has an electric motor that is secured to a lower end of a string of production tubing. The motor is powered by a power cable that extends alongside the tubing to the surface. The motor has an upper end with a drive shaft coupling. The pump for the motor is lowered through the production tubing on a wireline, wire rope or coiled tubing. The pump has a lower end which has a driven shaft coupling that makes up in stabbing engagement with the drive shaft coupling when the pump reaches the motor. The driven shaft coupling includes a guide which slides into a coupling housing. Orientating keys orient the guide and lock it from rotation.
    Type: Grant
    Filed: August 2, 1999
    Date of Patent: February 27, 2001
    Assignee: Baker Hughes Incorporated
    Inventor: Steven K. Tetzlaff
  • Patent number: 6186249
    Abstract: A release piece for a drill string is adapted to disengage upon activation in connection with a bit stuck in the lower portion of the bore hole during drilling. An elongated tubular release piece (10a, 10b) is, at the ends (12a, 12b) thereof, formed to be coupled into the drill string, upstream the bit. The drill string release piece comprises two substantially coaxial sleeve parts (10a, 10b) disposed in the continuation of each other and screwable together, the sleeve parts (10a, 10b) internally being provided with axially directed locking device (16a, 16a′, 16b, 16b′). An internal, axially displaceable locking device (18) has locking device (28′, 28″) capable of cooperating lockingly with the locking device (16a, 16a′, 16b, 16b′) of both sleeve parts (10a, 10b), the locking position being maintained by a spring (22).
    Type: Grant
    Filed: July 26, 1999
    Date of Patent: February 13, 2001
    Inventor: Thor Bjornstad
  • Patent number: 6173779
    Abstract: A well perforating apparatus has a first perforating gun section, a second perforating gun section, and a longitudinally collapsible unitary section connected between the first and second perforating gun sections. The unitary section can include a deformable member, or a frangible member, or a flexible member. One specific such member is a cable, such as implemented with a length of wireline material or slickline material. In a method of perforating a well having a plurality of zones to be perforated, a well perforating apparatus is lowered into the well. This includes separating a first perforating gun section from a second perforating gun section such that one gun section is adjacent one zone to be perforated and such that the other perforating gun section is adjacent another zone to be perforated.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: January 16, 2001
    Assignee: Halliburton Energy Services, Inc.
    Inventor: Ian W. Smith
  • Patent number: 6168213
    Abstract: A connector having a stinger and a receiver. The receiver is cocked by applying counter-acting torques to separate sections of the receiver. The counteracting torques compress a spring member. In the cocked position, the stinger is inserted into the receiver. When the counter-acting torques are released, the spring decompresses and locks the stinger in the receiver.
    Type: Grant
    Filed: June 27, 1997
    Date of Patent: January 2, 2001
    Assignee: Schlumberger Technology Corporation
    Inventor: Laurent E. Muller