|Publication number||US3463226 A|
|Publication date||Aug 26, 1969|
|Filing date||Nov 29, 1967|
|Priority date||Nov 29, 1967|
|Also published as||DE1811265A1|
|Publication number||US 3463226 A, US 3463226A, US-A-3463226, US3463226 A, US3463226A|
|Inventors||Johnson Glenn D|
|Original Assignee||Shell Oil Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (15), Classifications (27)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Aug. 26, 1969 Filed Nov. 29, 1967 G. D. JOHNSON UNDERWATER WELLHEAD APPARATUS 2 Sheets-Sheet 1 INVENTOR'.
GLENN D. JOHNSON BY; 9 5M HlS ATTORNEY 25, 1969 e. D. JOHNSON 3,463,226
UNDERWATER WELLHEAD APPARATUS Filed Nov. 29, 1967 2 Sheets-$heat 2 HIS ATTORNEY United States Patent O M 3,463,226 UNDERWATER WELLHEAD APPARATUS Glenn D. Johnson, Downey, Califi, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Nov. 29, 1967, Ser. No. 686,564 Int. Cl. EZlb 33/035; 1363c 11/00; B66c 1/62 U.S. Cl. 166-.5 8 Claims ABSTRACT OF THE DISCLOSURE Apparatus for carrying out operations at a wellhead positioned below the surface of a body of water while controlling the operations from a base positioned above the body of water. The apparatus comprises a wellhead assembly positioned below the water surface and at the top of a well drilled into the earth formations underlying the body of water. The wellhead assembly includes component means having movable portions thereof and a string of pipe affixed near its upper end to the wellhead assembly. The string of pipe extends downwardly into the earth formation, anchoring the wellhead assembly to the earth formation. Manipulator means is lowered through the water, removably positioned adjacent the Wellhead assembly and fixedly secured to the wellhead assembly. Arm means carried by the manipulator means includes grapple elements adapted to open and close about a piece of equipment. The grapple elements also include a wrench socket for turning bolts adapted to fit therein.
BACKGROUND OF THE INVENTION Field of the invention This invention relates to offshore wells drilled in earth formations lying below a body of water, wherein the wellhead equipment of the well is positioned below the surface of the water. The invention pertains more particularly to apparatus for manipulating equipment in the vicinity of, or which are components on, an underwater wellhead.
Description of the prior art This invention is an improvement over the underwater wellhead methods and apparatuses described in US. Patent No. 3,099,316, issued to Johnson July 30, 1963, and US. Patent No. 3,256,936, issued to Johnson et al. on
June 21, 1966. The history of drilling and completing oil and gas wells in the ocean floor was presented in detail in the above-mentioned patents; accordingly, further discussions leading up to the inventions of the above mentioned patents is deemed unnecessary.
The invention disclosed by Johnson involves a remotely-controlled manipulator device adapted to move through a body of water and be temporarily secured to an under: water wellhead while being movable therearound for carrying out any of the various operations of setting, adjusting, connecting or the disconnecting of a wellhead assembly positioned below the surface of a body of water, its components or associated equipment thereof. This manipulator device includes a rotatable object-engaging arm which is movable in any direction in a vertical or horizontal plane within the vicinity of the wellhead assembly. The rotatable arm, however, has grapple elements at one end and a wrench socket at the other. Thus, it is difiicult to maneuver the manipulator device when it is desired to simultaneously turn a bolt with the wrench socket while grasping a piece of equipment containing the bolt or in close proximity thereto.
In the patent to Johnson et al., the wrench socket (element 93 in FIGURES 6 and 7 of Johnson et a1.) is interchangeable with the grappling element when needed. However, this arrangement is undesirable for the reason 3,463,226 Patented Aug. 26, 1969 that the manipulator device must be surfaced to make this change.
SUMMARY OF THE INVENTION It is a primary object of this invention to provide apparatus for manipulating equipment in the vicinity of, or components on, a wellhead assembly positioned below the surface of a body of water.
A further object of the present invention to provide a remotely-controlled manipulator .device adapted to simultaneously grasp a piece of equipment while turning a bolt in close proximity to or carried by the piece of equipment.
It is a still further object of this invention to provide a simple and dependable method of combining a multiplicity of tools attached to a common spindle.
The apparatus for carrying out the invention comprises a wellhead assembly positioned below the surface of a body of water and at the top of a well drilled into the underlying earth formations. The wellhead assembly includes component means having movable portions thereof and a string of pipe affixed near its upper end to the wellhead assembly. The string of pipe extends downwardly into the earth formation anchoring the wellhead assembly to the earth formation. Manipulator means is lowered through the water, removably positioned adjacent the wellhead assembly and fixedly secured to the wellhead assembly. Arm means carried by the manipulator means includes grapple elements adapted to open and close about a piece of equipment. The grapple elements also include a wrench socket for turning bolts adapted to fit therein.
BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a diagrammatic view illustrating the manipulator device of the present invention positioned adjacent a wellhead assembly located on the ocean floor;
FIGURE 2 is a vertical sectional view of one embodiment of an arm of the manipulator device of FIGURE 1;
FIGURE 3 is a vertical sectional view taken along lines 3-3 of FIGURE 2; and
FIGURES 4 and 5 are vertical sectional views of a second embodiment of an arm of the manipulator device of FIGURE 1 showing the grapple elements in closed and open positions, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGURE 1 of the drawing, a foundation wellhead assembly 11 extends upwardly from the bottom 12 of a body of water 13. An operating station (not shown) is disposed on the surface of the body of water 13 above the approximate location of the assembly 11. The operating station may comprise means for raising and lowering a manipulator device 14 through operating line 15. A string of pipe 11a extends downwardly from assembly 11 into the earth bottom 12 as is well known in the art. For purposes of illustration, the wellhead assembly 11 is shown as being positioned on the ocean fioor 12. However, in many circumstances, for example, where the ocean floor is very muddy, it may be desirable to position the wellhead assembly 11 at some distance above the ocean floor 12 on the upper end of the conductor pipe 11a.
In the foregoing description, the term wellhead assembly is meant to'include any assemblage of components either fixedly or removably secured to the top of one or more strings of pipe extending into the ocean floor, either during the drilling, completion, production, re-working, or maintenance of a well. Thus, during the drilling of a well, the wellhead assembly may comprise certain components such as blow-out preventers, slips, etc., which would not be included therein when the well was being produced. Likewise, certain wellhead components of a producing well would be removed in order to carry out certain maintenance operations thereon.
Assembly 11 also includes, at its upper end, manipulator track 16 extending radially outwardly therearound. The manipulator track 16 is adapted to receive manipulator device 14 as described in detail in US. Patent No. 3,166,123 to Watkins. The manipulator device 14 is normally supported from the track 16 with operating cable or line attached thereto, the latter being suspended from the operating station. Electromotive and/or hydraulic force is conducted through the Operating line 15 from the station to the manipulator device 14 so as to operate wellhead components thereon, such as valves, and to secure elements to the foundation assembly through fastening bolts or other securing means.
Manipulator device 14 comprises a housing adapted to be lowered by means of line 15, swam into position by means of propellers 18 housing 17 and hung by means of a pair of wheels 19 on the track 16 to move thereabout while a pair of idler wheels 26 contact the outer surface of the larger diameter conductor pipe 21 which includes part of foundation assembly 11 as is well known in the art and described in detail in the patent to Johnson et al.
The manipulator device 14 is provided with at least one arm 22 preferably horizontally positioned, as illustrated, and adapted to move in and out, up and down, or to rotate at the discretion of an operator at a remote location on the operating station, as disclosed both hereinbelow and in the patent to Johnson. In this particular application, the movable arm 22 would be provided with a combination grapple device and wrench 23 for contacting movable components such as bolts 23a on the drilling head assembly 24. Lights 25 and a television camera 26 are preferably provided on the manipulator device 14 and are movable in any direction, normally being used to observe to operation carried out by the grapple device and wrench combination 23, or to align it on one of the bolts 23a. A movable operating arm 27 coupled to line 15 is pivotally attached to manipulator device 14 for operating the latter as discussed in detail in the patent to Johnson.
Turning to the embodiment of FIGURE 2, arm 22 includes a spindle housing 28 mounted or otherwise carried on the upper end of a vertical column( as, for example, column 29 in FIGURE 4), the latter being axially disposed within the body of the manipulator device 14 and remotely controlled in such a manner that the spindle 30 can be adjusted vertically and rotated with respect to the body. The tubular spindle 30 is axially contained within the body so that it can be rotated and/ or moved axially relative thereto.
A pair of partitions 31 and 32 integral with or otherwise connected to housing 28 form a piston chamber 33 therebetween. A piston 34 is carried on the inner end of spindle 30 and is reciprocable within chamber 33. Hydraulic pressure is introduced into chamber 33 through a pair of flexible hoses 35 and 36.
A first hose 35 is in communication at one end with a pressurized fluid source (not shown) and at the other end with a passageway 37 extending through partition 31. A second hose 36 is in communication at one end with a pressurized fluid source (also not shown) and at the other end with a passageway 38 extending through partition 32.
In operation, piston 34 co-acts with the cylindrical bore 39 of housing 28 in such a manner that, when hydraulic pressure is introduced through flexible hose 35, the spindle 30 is extended outwardly from housing 28. In reversing the flow of hydraulic pressure whereby it is admitted through flexible hose 36, the spindle 30, integral with or otherwise connected to piston 34, is caused to be retracted.
In order to impart rotation to spindle 30, a motor 40 is secured at 41 to the spindle housing 28 and coupled at 41 to a spline shaft 42, the latter being in engagement with the internal spline bore 43 of spindle 30. Shaft 42 passes through a bearing member 44 mounted in a partition 45 integral with or otherwise connected to housing 28. Shaft 42 also passes through an O-ring 46 mounted in an opening 47 formed in partition 31. Piston 34 also includes an O-ring 48 extending about its periphery and engaging bore 39. Spindle 30 passes through an O-ring 49 mounted in an opening 50 formed in partition 32.
In operation, the actuation of motor 40 through electric means (not shown) coupled to motor 40 through wires 51, directs as Well as controls the rotation of spindle 30.
As is illustrated in FIGURE 2, the outward operating end of the spindle 30 is provided with a manipulating head 52 which is mounted on the enlarged cup portion 53 integral with spindle 30. The upper grapple jaw portion 54 of head 52 is retained on partition 73 of cup portion 53 by means of a pin 55 mounted thereon. A lower grapple jaw portion 56 is integral with the bottom portion 57 of cup portion 53. A linkage 58 is pivotally attached to upper jaw portion 54. Linkage 58 has an endless slot 59 formed therein which engages a pin 60 integral with or otherwise fixed to the free end of a shaft 61. The pin 60 rides in slot 59 when shaft 61 is axially reciprocated within piston chamber 62. Piston chamber 62 is formed by a pair of partitions 63 and 64. The other end of shaft 61 is coupled to a piston 65 having an O-ring 66 extending about its periphery and adapted to engage the bore 67 of chamber 62. A resilient coil spring 68 is fastened at one end to partition 63 and at its other end to piston 65. Shaft 61 is slidable within an O-ring 69 mounted in an opening 70 formed in partition 64. Shaft 61 is also slidable Within an O-ring 71 mounted in an opening 72 formed in partition 73.
Hydraulic fluid is conducted into piston chamber 62 by means of a flexible hose 74 (FIGURE 3) in communication at one end with a pressurized fiuid source (not shown) and at the other end with a passageway 75 formed in bottom portion 57. Flexible hose 74 is reciprocable within a slot 76 formed in spindle housing 28.
A wrench socket 77 is formed or otherwise fixed in the extreme outer end 78 of the manipulator head 52. The longitudinal axis of socket 77 is preferably co-axial with the longitudinal axis of arm 22 of manipulating device 14. Wrench socket 77 is adapted to turn, in one direction or the other, bolts 23a adapted to fit therein.
In operation, manipulating device 14 is lowered into engagement with foundation assembly 11 and propelled about track 16 as discussed hereinabove. The grapplewrench device 23 of arm 22 is moved into engagement with selected instrumentation on assembly 11. For example, hoses and guide lines may be carried into place on assembly 11 by the grapple portion (i.e., jaws 54 and 56) of grapple-wrench device 23 and attached to the wellhead assembly and/or flowline connections. Wrench socket 77 simultaneously engages any necessary bolts on the well head assembly without the necessity of bringing device 14 to the surface to make necessary tool changes as required in prior art devices.
The manipulator device 14 is remotely controlled in such a manner that spindle 30, coupled to spline shaft 47, is rotated with respect to housing 28 through motor 40. Introduction of hydraulic fluid into piston chamber 33 through flexible hoses 35 and 36 selectively extends and retracts spindle 30 within housing 28.
The manipulating head 52 of grapple-wrench device 23 is operated independently of spindle 30. Introduction and withdrawal of hydraulic fluid into piston chamber 62 through flexible hose 74 selectively extends and retracts shaft 61 coupled to spring-biased piston 65. The free end of shaft 61 carries the manipulating head 52, head 52 having a linkage 58 coupled to an upper jaw portion 54. Linkage 58 has an endless slot 59 therein engaging pin 60 on shaft 61 so as to pivot upper jaw portion 54 about a pin 55 mounted on partition 73. In this maner, the arm 22 of the manipulating device 14 of FIGURE 2 is actuated in the manner described hereinabove.
Turning now to the embodiment of FIGURES 4 and 5, arm 79 includes a spindle housing 80 mounted on or otherwise carried on the upper end of vertical column 29 which is axially disposed within the body of the manipulator device 14 and remotely controlled as discussed above concerning arm 22 of FIGURE 2.
A pair of partitions 81 and 82 integral with or otherwise fastened to housing 28, as, for example, by screws 83 and 84, respectively, form a piston chamber 85 therebetween. A piston 86 is carried on the inner end of a spindle 87 and is reciprocable within chamber 85. Hydraulic pressure is introduced into chamber 33 through a pair of flexible hoses 88 and 89.
A first hose 88 is in communication at one end with a pressurized fluid source (not shown) and at the other end with a passageway 90 extending through housing 80. A second hose 89 is in communication at one end with a. pressurized fluid source (also not shown) and at the other end with a passageway 91 extending through housing 80.
In operation, piston 86 co-acts with the cylindrical bore 92 of housing 80 in such a manner that, when hydraulic pressure is introduced through flexible hose 89, the spindle 87 is extended outwardly from housing 80. When hydraulic pressure is introduced through flexible hose 88, the spindle 87, integral with or otherwise connected to piston 86, is retracted into housing 80.
Piston 86 also includes a pair of inwardly and outwardly radially extending O-rings 93 and 94, respectively. A sealing member 95, which includes a radially extending O-ring 96 and surrounds a packing member 97, abuts partition 81 with spindle 87 slidable therethrough. In order to impart rotation to spindle 87, a fluid motor 98 is secured as by screws 84 to partition 82. Motor 98 is coupled through motor shaft 99 to a spline shaft 100. Spline shaft 100 is in engagement with the internal spline bore 101 of spindle 87. Shaft 100 passes through a bearing member 102 mounted in a partition 103 also connected to housing 80 through screws 84. O-rings 104 extend radially about the faces of partition 103 as can be seen in FIGURE 4. The admission of hydraulic fluid to fluid motor 98 through either flexible hose 104 or 105 directs as well as controls the rotation of spindle 87 as is well known in the art.
As illustrated in FIGURE 4, the outward operating end of spindle 87 is provided with a manipulating head 106 which is telescopically received in the enlarged cup portion 107 integral with spindle 87. The upper grapple jaw portion 108 of head 106 includes a tubular extension portion 109 which extends into cup portion 107 and includes an inward movement limiting abutment portion 110. A lower grapple jaw portion 111 is pivotally carried in head 106 by a pivot pin 112 fixed to portion 108. A linkage 113 pivotally connects grapple jaw portion 111 at pivot 113a to a piston shaft 114. Piston shaft 114 is connected at pivot 113b to a piston 115 slidably mounted in piston chamber 116. Piston 115 also includes a plurality of radially extending O-rings 117. A compression spring 118 is connected at one end to a linkage button 119 which abuts against the upper portion 120 of lower jaw portion 111 and at its opposite end to a member 121 screw-threaded or otherwise mounted in upper jaw portion 108.
A slip ring 122 is carried by the manipulating head 106 in a manner such that head 106 may rotate therein and ring 122 is axially moved with head 106. A hollow guide bar 123 is carried by the slip ring 122, for example, screw-threaded as at 124, and arranged to slide within a bushing 125 formed or otherwise mounted in an extension portion 126 of housing 80 so as to prevent relative rotation of slip ring 122 with respect to spindle housing 80.
A flexible hose 127 is coupled at 128 to the free end of bar 123 and in communication with a passageway 129 extending through slip ring 122. Passageway 129 is in communication with holes 130 in the center spacing ring 130a of a packing cell 131. Holes 130 are in communication with a passageway 132 extending through extension portion 109. An annular space 133 is formed between a cylinder 134 and portion 109. A passageway 135 extends through cylinder 135 and a pin 136 retains portion 109 in engagement with cup portion 107. Pin 136 is slidable within a space 137 formed between slip ring 122 and cup portion 107.
A wrench socket 138 is formed or otherwise fixed in the extreme outer end 139 of the manipulator head 106. In the embodiment of FIGURE 4, socket 138 is preferably shown as a separable member 140 insertible in a passageway 141 in outer end 139 and retainable therein by a pin 142. The longitudinal axis of socket 138 is coaxial with the longitudinal axis of the spindle 87 as discussed previously in the embodiment of FIGURE 2. A removable cover plate 143 may be provided to retain all the linkage pins in position when the plate 143 is assembled by bolts (not shown) or other suitable fastening means. In this manner, ready access may be had to linkage 113.
In operation, once arm 79 and spindle 87 are in position in the manner discussed previously, hydraulic pressure is applied to piston in chamber 116 so that the lower grapple jaw portion 111 may move into gripping engagement (FIGURE 4). Compression spring 118, acting against portion 111, returns portion 111 to the open or released position of FIGURE 5. The dotted lines of FIGURE 4 indicate a hose or guide line gripped by jaws 108 and 111 prior to release therefrom.
Slip ring 122 permits hydraulic pressure to be conducted to piston 115 so that jaw portion 111 may be operated independently of the spindle 87 or rotational or axial adjustment. The hydraulic pressure fluid is introduced through hose 127 from a fluid pressure source (not shown) and into guide bar 123. The fluid then passes through the holes 130 in ring 130a and thus through passageway 132 in tubular extension portion 109 and into the annular space 133 between cylinder 134 and portion 109. From there, the fluid enters piston chamber 116 through passageway 135. This moves piston 115 from the release position of FIGURE 5 to the gripping position of FIGURE 4. Linkage 113 pivots jaw portion 111 into gripping engagement with the hose, guide line, or other instrument desired. The upper portion of jaw portion 111 abuts against spring-biased button 119 and maintains this position until release.
At this point, motor 98 may be actuated to rotate shaft 87 which is coupled to tubular portion 109 through pin 136. In this manner, wrench socket 138 may be rotated while in engagement with a bolt as discussed previously in the embodiment of FIGURE 2. Finally, withdrawal of fluid from chamber 116 enables piston 115 to move to the right (i.e., release position of FIGURE 5) and spindle 87 may be retracted as desired in the manner discussed hereinabove.
While only one general type of manipulator device has been described in detail, it is understood that any other type of manipulator device may be employed which is movable along a track adjacent a wellhead assembly.
The manipulator device of the present invention may be employed to carry out operations at any well production facilities positioned below the surface of a 'body of water which is provided with a suitable track or tracks on which the manipulator device may be propelled to its various indexed positions around the facilities. Underwater well production facilities, as employed herein, may comprise a wellhead assembly together with flow lines as described hereinabove. It may also include other production equipment such as underwater tanks positioned below the surface of the water for collecting, storing or metering production fluid from underwater wells, or for treating or separating the production fluid and then handling the separate phases thereof. Underwater tanks, if used, are preferably positioned around a wellhead assembly so that the manipulator device could be employed on its tracks by merely rotating the operative arm of the manipulator so that it is directed outwardly 7 away from the wellhead assembly where it could engage, control, or adjust the operative components such as valves, connectors, level controllers, etc., of normal production facilities. Also, Well production facilities having a track for a manipulator device could be positioned on the ocean floor between two or more wells.
The telescoping or advancing type arm and power wrench may be of any suitable design and construction, as, for example, similar to that shown in US. Patents 2,637,527 and 2,673,452. Alternatively, the grapple elements of the arms may be provided with a wrench socket (not shown) set at 90 degrees to the axis of the arm for turning bolts or other devices whose axis is positioned normal to the axis of the arm. A power wrench of this design is shown in US. Patent 2,854,217. Also, the arms could he provided with strain gauges to measure the amount of torque imposed by the wrench socket in turning an element.
Various apparatuses for varrying out the concepts of this invention may become apparent to one skilled in the art, and it is to be understood that such modifications fall within the scope of the appended claims.
I claim as my invention:
1. Apparatus for carrying out operations at a wellhead positioned below the surface of a body of water while controlling the operations from a base positioned above the body of water comprising a wellhead assembly, said Wellhead assembly being positioned below the water surface and at the top of a well drilled into the earth formations underlying the body of water, said wellhead assembly including component means having movable portions thereof, manipulator means removably positionable adjacent and adapted to be secured to the wellhead assembly, arm means carried by the manipulator means, said arm means including both grapple means adapted to open and close about a piece of equipment and a wrench socket for turning bolts adapted to be engaged thereby, wherein said grapple means carries said wrench socket.
2. The apparatus of claim 1 wherein said arm means is horizontally positioned on said manipulator means;
said grapple means being coupled to a shaft extending parallel to and contained within said arm means; and
said manipulator means including prime mover means coupled to said shaft adapted to extend and retract said shaft from said arm means.
3. The apparatus of claim 2 wherein said manipulator means further includes second prime mover means cou-. pled to said shaft adapted to rotate said shaft within said manipulator means.
4. The apparatus of claim 3 wherein said grapple means includes at least a first movable portion adapted to move into spring-biased gripping relationship with a second non-movable portion.
5. The apparatus of claim 4 wherein said first movable portion includes a lower spring-biased pivoted jaw portion;
said second non-movable portion being a fixed upper gripping portion including compression spring means having a button portion coupled thereto adapted to abut against said lower jaw portion; and
said compression spring means compressing said button outwardly from said upper gripping portion so as to bring said lower jaw portion into gripping relationship with said second non-movable portion.
6. The apparatus of claim 5 including a linkage arm pivotally coupled to said lower jaw portion;
a piston shaft pivotally coupled to said linkage arm;
piston means fixed to said piston shaft for opening and closing said first and second portions;
third prime mover means operatively engaging said piston means for extending and retracting said piston shaft from said arm means; and
said third prime mover means being actuable independent of said first and second prime mover means.
7. The apparatus of claim 6 wherein:
said wrench socket is carried by said second nonmovable portion, opens outwardly of said shaft and has its longitudinal axis co-axial with the longitudinal axis of said shaft.
8. The apparatus of claim 4 wherein said first movable portion includes an upper jaw portion adapted to be moved into gripping relationship with said second nonmovable portion;
a piston shaft being connected at one end to said first movable portion;
spring-biased piston means connected to the other end of said arm means;
said second non-movable portion being fixed to said arm means;
said wrench socket being carried by said second nonmovable portion, opening outwardly of said shaft and having its longitudinal axis co-axial with the longitudinal axis of said shaft; and
third prime mover means operatively engaging said piston means for actuating said piston means independent of said first and second prime mover means.
References Cited UNITED STATES PATENTS 2,040,956 5/1936 Romano 61-69 3,099,316 7/1963 Johnson 166-.6 3,299,950 1/1967 Shatto 166-.5 3,381,485 5/1968 Crooks et a1 61-69 3,418,818 12/1968 Vincent et al. -6 X CHARLES E. OCONNELL, Primary Examiner RICHARD E. FAVREAU, Assistant Examiner US. Cl. X.R.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2040956 *||Mar 27, 1933||May 19, 1936||Lula Romano||Underwater salvage device|
|US3099316 *||Apr 25, 1960||Jul 30, 1963||Shell Oil Co||Underwater wellhead apparatus and method|
|US3299950 *||Jun 20, 1963||Jan 24, 1967||Shell Oil Co||Pipe line connector|
|US3381485 *||Oct 23, 1965||May 7, 1968||Battelle Development Corp||General purpose underwater manipulating system|
|US3418818 *||Apr 22, 1966||Dec 31, 1968||Pan American Petroleum Corp||Underwater power source|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4149818 *||Aug 22, 1977||Apr 17, 1979||Perry Oceanographics, Inc.||Submersible chamber arrangement|
|US4460295 *||Feb 22, 1982||Jul 17, 1984||Compagnie Francaise Des Petroles||Submersible connector|
|US4602893 *||Feb 19, 1985||Jul 29, 1986||Shell Offshore Inc.||Ring gasket installation tool|
|US4618285 *||Feb 19, 1985||Oct 21, 1986||Shell Offshore Inc.||Buoyant ring gasket installation tool|
|US4648782 *||May 27, 1983||Mar 10, 1987||Kraft Brett W||Underwater manipulator system|
|US4936743 *||Mar 16, 1989||Jun 26, 1990||Siemens Aktiengesellschaft||Hydraulically controlled gripper tool|
|US5203645 *||Jan 10, 1992||Apr 20, 1993||The United States Of America As Represented By The United States Department Of Energy||Underwater manipulator|
|US5234244 *||Feb 27, 1992||Aug 10, 1993||Korea Institute Of Science And Technology (Kist)||Bi-directional feeding gripper device|
|US5273376 *||Feb 10, 1992||Dec 28, 1993||Shell Offshore Inc.||Back-up connector release tool|
|US8875798 *||Apr 16, 2010||Nov 4, 2014||National Oilwell Varco, L.P.||Wellsite replacement system and method for using same|
|US8978766 *||Sep 13, 2011||Mar 17, 2015||Schlumberger Technology Corporation||Temperature compensated accumulator|
|US9022126||Jun 15, 2010||May 5, 2015||National Oilwell Varco, L.P.||Wellsite equipment replacement system and method for using same|
|US20100270746 *||Oct 28, 2010||National Oilwell Varco, L.P.||Wellsite Replacement System and Method for Using Same|
|DE2725880A1 *||Jun 8, 1977||Dec 22, 1977||Emh||Verbesserungen an werkzeugen zur handhabung von vorrichtungen, wie z.b. elastischen gelenken, insbesondere fuer gelenksaeulen, auf dem meeresgrund|
|EP0295208A1 *||Jun 2, 1988||Dec 14, 1988||Gebrüder Sulzer Aktiengesellschaft||Robot gripper and arrangement of such a gripper|
|U.S. Classification||166/351, 901/39, 901/37, 166/368, 294/66.1, 901/30, 81/52, 405/191|
|International Classification||E21B41/00, E21B33/03, E21B41/04, E21B33/035, B25J15/00, B25J9/14, E21B7/12|
|Cooperative Classification||E21B41/0007, B25J15/00, E21B7/12, E21B33/035, E21B41/04, B25J9/144|
|European Classification||B25J15/00, E21B7/12, B25J9/14L, E21B41/00A, E21B41/04, E21B33/035|