Patent Publication Number: US-2016245037-A1

Title: Oilfield device with wireless telemetry

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 12/643,093 filed Dec. 21, 2009, which claims the benefit of U.S. Provisional Application No. 61/205,209 filed Jan. 15, 2009, which are hereby incorporated by reference for all purposes in their entirety. 
     This application claims the benefit of U.S. Provisional Application No. 61/394,155 filed on Oct. 18, 2010, which is hereby incorporated by reference for all purposes in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     REFERENCE TO MICROFICHE APPENDIX 
     N/A 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to subsea drilling, and in particular to a system and method for unlatching and/or latching a rotating control device (RCD) or other oilfield device. 
     2. Description of Related Art 
     Marine risers extending from a wellhead fixed on the floor of an ocean have been used to circulate drilling fluid back to a structure or rig. An example of a marine riser and some of the associated drilling components is proposed in U.S. Pat. Nos. 4,626,135 and 7,258,171. RCDs have been proposed to be positioned with marine risers. U.S. Pat. No. 6,913,092 proposes a seal housing with a RCD positioned above sea level on the upper section of a marine riser to facilitate a mechanically controlled pressurized system. U.S. Pat. No. 7,237,623 proposes a method for drilling from a floating structure using an RCD positioned on a marine riser. U.S. Pat. Nos. 6,470,975, 7,159,669; and 7,258,171 propose positioning an RCD assembly in a housing disposed in a marine riser. In the &#39;171 patent, the system for drilling in the floor of an ocean uses a RCD with a bearing assembly and a holding member for removably positioning the bearing assembly in a subsea housing. Also, an RCD has also been proposed in U.S. Pat. No. 6,138,774 to be positioned subsea without a marine riser. 
     More recently, the advantages of using underbalanced drilling, particularly in mature geological deepwater environments, have become known. RCD&#39;s, such as disclosed in U.S. Pat. No. 5,662,181, have provided a dependable seal between a rotating pipe and the riser while drilling operations are being conducted. U.S. Pat. No. 6,138,774 proposes the use of a RCD for overbalanced drilling of a borehole through subsea geological formations. U.S. Pat. No. 6,263,982 proposes an underbalanced drilling concept of using a RCD to seal a marine riser while drilling in the floor of an ocean from a floating structure. Additionally, U.S. Provisional Application No. 60/122,350, filed Mar. 2, 1999, entitled “Concepts for the Application of Rotating Control Head Technology to Deepwater Drilling Operations” proposes use of a RCD in deepwater drilling. U.S. Pat. No. 4,813,495 proposes a subsea RCD as an alternative to the conventional drilling system and method when used in conjunction with a subsea pump that returns the drilling fluid to a drilling vessel. 
     Conventional RCD assemblies have been sealed with a subsea housing using active sealing mechanisms in the subsea housing. Pub. No. US 2010/0175882 proposes a mechanically extrudable seal or a hydraulically expanded seal to seal the RCD with the riser. Additionally, conventional RCD assemblies, such as proposed by U.S. Pat. No. 6,230,824, have used powered latching mechanisms in the subsea housing to position the RCD. U.S. Pat. No. 7,487,837 proposes a latch assembly for use with a riser for positioning an RCD. U.S. Pat. No. 7,836,946 B2 proposes a latching system to latch an RCD to a housing and active seals. U.S. Pat. No. 7,926,593 proposes a docking station housing positioned above the surface of the water for latching with an RCD. Pub. No. US 2009/0139724 proposes a latch position indicator system for remotely determining whether a latch assembly is latched or unlatched. 
     U.S. Pat. No. 6,129,152 proposes a flexible rotating bladder and seal assembly that is hydraulically latchable with its rotating blow-out preventer housing. U.S. Pat. No. 6,457,529 proposes a circumferential ring that forces dogs outward to releasably attach an RCD with a manifold. U.S. Pat. No. 7,040,394 proposes inflatable bladders/seals. U.S. Pat. No. 7,080,685 proposes a rotatable packer that may be latchingly removed independently of the bearings and other non-rotating portions of the RCD. The &#39;685 patent also proposes the use of an indicator pin urged by a piston to indicate the position of the piston. 
     Latching assemblies for RCDs have been proposed to be operated subsea with an electro-hydraulic umbilical line from the surface. A remotely operated vehicle (ROV) and a human diver have also been proposed to operate the latching assemblies. However, an umbilical line may become damaged. It is also possible for sea depths and/or conditions to be unsafe and/or impractical for a diver or a ROV. In such situations, the marine riser may have to be removed to extract the RCD. 
     U.S. Pat. No. 3,405,387 proposes an acoustical control apparatus for controlling the operation of underwater valve equipment from the surface. U.S. Pat. No. 4,065,747 proposes an apparatus for transmitting command or control signals to underwater equipment. U.S. Pat. No. 7,123,162 proposes a subsea communication system for communicating with an apparatus at the seabed. Pub. No. US 2007/0173957 proposes a modular cable unit positioned subsea for the attachment of devices such as sensors and motors. 
     The above discussed U.S. Pat. Nos. 3,405,387; 4,065,747; 4,626,135; 4,813,495; 5,662,181; 6,129,152; 6,138,774; 6,230,824; 6,263,982; 6,457,529; 6,470,975; 6,913,092; 7,040,394; 7,080,685; 7,123,162; 7,159,669; 7,237,623; 7,258.171; 7,487,837; 7,836,946 B2; and 7,926,593 and Pub. Nos. US 2007/0173957; 2009/0139724; and 2010/0175882; and U.S. Provisional Application No. 60/122,350, filed Mar. 2, 1999, entitled “Concepts for the Application of Rotating Control Head Technology to Deepwater Drilling Operations” are all hereby incorporated by reference for all purposes in their entirety. 
     It would be desirable to have a system and method to unlatch an RCD or other oilfield device from a subsea latching assembly when the umbilical line primarily responsible for operating the latching assembly is damaged or use of the umbilical line is impractical or not desirable, and using a diver or an ROV may be unsafe or impractical. 
     BRIEF SUMMARY OF THE INVENTION 
     An acoustic control system may remotely operate a subsea latch assembly. In one embodiment, the acoustic control system may control a subsea first accumulator storing hydraulic fluid. The hydraulic fluid may be pressurized. The first accumulator may be remotely and/or manually charged and purged. In response to an acoustic signal, the first accumulator may release its fluid to operate the subsea latching assembly. The released fluid may move a piston in the latching assembly to unlatch an RCD or other oilfield device. The latching assembly may be disposed with a marine riser and/or a subsea wellhead if there is no marine riser. If there is a marine riser, the latching assembly may be disposed below the tension lines or tension ring supporting the top of the riser from the drilling structure or rig. 
     The acoustic control system may have a surface control unit, a subsea control unit, and two or more acoustic signal devices. One of the acoustic signal devices may be capable of transmitting an acoustic signal, and the other acoustic signal device may be capable of receiving the acoustic signal. In one embodiment, acoustic signal devices may be transceivers connected with transducers each capable of transmitting and receiving acoustic signals between each other to provide for two-way communication between the surface control unit and the subsea control unit. The subsea control unit may control the first accumulator. 
     A second accumulator or a compensator may be used to capture hydraulic fluid moving out of the latching system to prevent its escape into the environment. The acoustic control system may be used as a secondary or back-up system in case of damage to the primary electro-hydraulic umbilical line, or it may be used as the primary system for operating the latching assembly. In one embodiment, one or more valves or a valve pack may be disposed with the accumulators and the umbilical line to switch to the secondary acoustic control system as needed. 
     In other embodiments, the acoustic control system may be used to both latch and/or unlatch the RCD or other oilfield device with the subsea housing or marine riser, including by moving primary and/or secondary pistons within the latch assembly. In another embodiment, the system may be used to operate active seals to retain and/or release a RCD or other oilfield device disposed with a subsea housing or marine riser. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention can be obtained with the following detailed descriptions of the various disclosed embodiments in the drawings, which are given by way of illustration only, and thus are not limiting the invention, and wherein: 
         FIG. 1  is a cross-sectional elevational view of an RCD having two passive seals and latched with a riser spool or housing having two latching members shown in the latched position and an active packer seal shown in the unsealed position. 
         FIG. 1A  is a section view along stepped line  1 A- 1 A of  FIG. 1  showing second retainer member as a plurality of dogs in the latched position, a plurality of vertical grooves on the outside surface of the RCD, and a plurality of fluid passageways between the dogs and the RCD. 
         FIG. 2  is a cross-sectional elevational view of an RCD with three passive seals latched with a riser spool or housing having two latching members shown in the latched position, an active seal shown in the unsealed position, and a bypass channel or line having a valve therein. 
         FIG. 3A  is a cross-sectional elevational partial view of an RCD having a seal assembly disposed with an RCD running tool and latched with a riser spool or housing having two latching members shown in the latched position and an active seal shown in the sealed position. 
         FIG. 3B  is a section view along line  3 B- 3 B of  FIG. 3A  showing an ROV panel and an exemplary placement of lines, such as choke lines, kill lines, booster lines, umbilical lines and/or other lines, cables and conduits around the riser spool. 
         FIGS. 4A-4B  are a cross-sectional elevational view of an RCD with three passive seals having a seal assembly disposed with an RCD running tool and latched with a riser spool or housing having three latching members shown in the latched position, the lower latch member engaging the seal assembly, and a bypass conduit or line having a valve therein. 
         FIGS. 5A-5B  are a cross-sectional elevational view of an RCD with three passive seals having a seal assembly disposed with an RCD running tool and sealed with a riser housing and the RCD latched with the riser housing having two latching members shown in the latched position and a bypass conduit or line having a valve therein. 
         FIG. 6A  is a cross-sectional elevational partial view of an RCD having a seal assembly with a mechanically extrudable seal assembly seal shown in the unsealed position, the seal assembly having two unsheared shear pins and a ratchet shear ring. 
         FIG. 6B  is a cross-sectional elevational partial broken view of the RCD of  FIG. 6A  with the RCD running tool moved downward from its position in  FIG. 6A  to shear the seal assembly upper shear pin and ratchet the ratchet shear ring to extrude the seal assembly seal to the sealed position. 
         FIG. 6C  is a cross-sectional elevational partial broken view of the RCD of  FIG. 6B  with the RCD running tool moved upward from its position in  FIG. 6B , the seal assembly upper shear pin sheared but in its unsheared position, the ratchet shear ring sheared to allow the seal assembly seal to move to the unsealed position, and the riser spool or housing latching members shown in the unlatched position. 
         FIG. 7A  is a cross-sectional elevational partial view of an RCD having a seal assembly with a seal assembly seal shown in the unsealed position, the seal assembly having upper, intermediate, and lower shear pins, a unidirectional ratchet or lock ring, and two concentric split C-rings. 
         FIG. 7B  is a cross-sectional elevational partial broken view of the RCD of  FIG. 7A  with the RCD running tool moved downward from its position in  FIG. 7A , the seal assembly upper shear pin and lower shear pin shown sheared and the ratchet ring ratched to extrude the seal assembly seal to the sealed position. 
         FIG. 7C  is a cross-sectional elevational partial broken view of the RCD of  FIG. 7B  with the RCD running tool moved upward from its position in  FIG. 7B , the seal assembly upper shear pin and lower shear pin sheared but in their unsheared positions, the intermediate shear pin sheared to allow the seal assembly seal to move to the unsealed position while all the riser spool or housing latching members remain in the latched position. 
         FIG. 8A  is a cross-sectional elevational partial split view of an RCD having a seal assembly with a seal assembly seal shown in the unsealed position and a RCD seal assembly loss motion connection latched with a riser spool or housing, on the right side of the break line an upper shear pin and a lower shear pin disposed with an RCD running tool both unsheared, and on the left side of the break line, the RCD running tool moved upward from its position on the right side of the break line to shear the lower shear pin. 
         FIG. 8B  is a cross-sectional elevational partial broken view of the RCD of  FIG. 8A  with the RCD running tool moved upward from its position on the left side of the break line in  FIG. 8A , the lower latch member retainer moved to the lower end of the loss motion connection and the unidirectional ratchet ring ratcheted upwardly to extrude the seal assembly seal. 
         FIG. 8C  is a cross-sectional elevational partial broken view of the RCD of  FIG. 8B  with the RCD running tool moved downward from its position in  FIG. 8B , the seal assembly seal in the sealed position and the radially outward split C-ring moved from its concentric position to its shouldered position. 
         FIG. 8D  is a cross-sectional elevational partial broken view of the RCD of  FIG. 8C  with the RCD running tool moved upward from its position in  FIG. 8C  so that a running tool shoulder engages the racially inward split C-ring. 
         FIG. 8E  is a cross-sectional elevational partial broken view of the RCD of  FIG. 8D  with the RCD running tool moved further upward from its position in  FIG. 8D  so that the shouldered C-rings shear the upper shear pin to allow the seal assembly seal to move to the unsealed position after the two upper latch members are unlatched. 
         FIG. 9A  is a cross-sectional elevational partial view of an RCD having a seal assembly with a seal assembly seal shown in the unsealed position, a seal assembly latching member in the latched position, upper, intermediate and lower shear pins, all unsheared, and an upper and a lower unidirectional ratchet or lock rings, the RCD seal assembly disposed with an RCD running tool, and latched with a riser spool having three latching members shown in the latched position and a bypass conduit or line. 
         FIG. 9B  is a cross-sectional elevational partial broken view of the RCD of  FIG. 9A  with the RCD running tool moved downward from its position in  FIG. 9A , the upper shear pin sheared and the lower ratchet ring ratcheted to extrude the seal assembly seal. 
         FIG. 9C  is a cross-sectional elevational partial broken view of the RCD of  FIG. 9B  with the RCD running tool moved downward from its position in  FIG. 9B , the lower shear pin sheared, and the seal assembly seal to the sealed position and the radially outward garter springed segments moved from their concentric position to their shouldered position. 
         FIG. 9D  is a cross-sectional elevational partial broken view of the RCD of  FIG. 9C  with the RCD running tool moved upward from its position in  FIG. 9C  so that the shouldered garter spring segments shear the intermediate shear pin to allow the seal assembly dog to move to the unlatched position after the two upper latch members are unlatched. 
         FIG. 9E  is a cross-sectional elevational partial broken view of the RCD of  FIG. 9D  with the RCD running tool moved further upward from its position in  FIG. 9D , the lower shear pin sheared but in its unsheared position, the seal assembly dog in the unlatched position to allow the seal assembly seal to move to the unsealed position after the two upper latch members are unlatched. 
         FIG. 10A  is a cross-sectional elevational partial view of an RCD having a seal assembly, similar to  FIG. 4B , with the seal assembly seal shown in the unsealed position, a seal assembly dog shown in the latched position, unsheared upper and lower shear pins, and a unidirectional ratchet or lock ring, the lower shear pin disposed between an RCD running tool and garter springed segments, and a riser spool having three latching members shown in the latched position and a bypass conduit or line. 
         FIG. 10B  is a cross-sectional elevational partial broken view of the RCD of  FIG. 10A  with the RCD running tool moved upward from its position in  FIG. 10A , the RCD seal assembly loss motion connection receiving the lower latch member retainer and the lower shear pin sheared to allow the lower garter springed segments to move inwardly in a slot on the running tool. 
         FIG. 10C  is a cross-sectional elevational partial broken view of the RCD of  FIG. 10B  with the RCD running tool moved downward after it had moved further upward from its position in  FIG. 10B  to move the lower latch member retainer to the lower end of the loss motion connection and the unidirectional ratchet or lock ring maintaining the seal assembly seal in the sealed position and to move the upper garter springed segments from their concentric position to their shouldered position. 
         FIG. 10D  is a cross-sectional elevational partial broken view of the RCD of  FIG. 10C  with the RCD running tool moved upward from its position in  FIG. 10C  after running down hole, so the shouldered garter spring segments shear the upper shear pin while the seal assembly seal is maintained in the sealed position after the two upper latch members are unlatched. 
         FIG. 10E  is a cross-sectional elevational partial broken view of the RCD of  FIG. 10D  with the RCD running tool moved further upward from its position in  FIG. 10D  so the seal assembly dog can move to its unlatched position to allow the seal assembly seal to move to the unsealed position after the two upper latch members are unlatched. 
         FIG. 11  is a cross-sectional elevational view of an RCD disposed with a single hydraulic latch assembly. 
         FIG. 12  is a cross-sectional elevational view of an RCD disposed with a dual hydraulic latch assembly. 
         FIG. 13  is an elevational view of an RCD latched with a latching assembly (not shown) in a housing with a first umbilical line on the left side extending from a first umbilical line reel and connected with the housing, and a second umbilical line on the right side extending from a second umbilical line reel and attached with a valve pack (not shown) connected to accumulators, with a signal device in a stowed position below the accumulators. 
         FIG. 14  is a schematic view of an acoustic control system including a surface control unit, a subsea control unit, a first acoustic signal device supported below sea level from a reel, and second and third acoustic signal devices shown in exploded view disposed with a valve pack and a plurality of subsea accumulators positioned with a subsea housing having an internal latching assembly. 
         FIG. 15  is a schematic view of the accumulators and valve pack of  FIG. 14  disposed with hydraulic lines, check valves, and sensors. 
         FIG. 16  is a schematic view of the acoustic control system of  FIGS. 14 and 15  with the valve pack and accumulators disposed with a semi-submersible floating rig positioned with a marine riser and BOP stack over a wellhead in elevational view. 
         FIG. 17  is a cross-sectional elevational view of an RCD disposed with a subsea housing allowing drilling with no marine riser. 
         FIG. 18  is a cross-sectional elevational view of an RCD disposed with a subsea housing over a subsea BOP stack allowing drilling with no marine riser. 
         FIG. 19  is an elevational view of an RCD in phantom view latchable with a housing, with accumulators releaseably coupled with the housing with an accumulator clamp ring, and a signal device disposed below the accumulators in a stowed position. 
         FIG. 20  is the same as  FIG. 19  except with the signal device in a deployed position. 
         FIG. 21  is the same as  FIG. 19  except with the housing rotated 90 degrees about a vertical axis to show three operating accumulators and one receiving accumulator or compensator. 
         FIG. 22  is a plan view of  FIG. 21  with the four accumulators attached with the housing with an accumulator clamp ring, and with the signal device moved from a stowed position, in phantom view, to a deployed position. 
         FIG. 23A  is a schematic view of the accumulators and valve pack of  FIG. 14  disposed with hydraulic lines, check valves, and sensors. 
         FIG. 23B  is a schematic view of the accumulators and valve pack of  FIG. 14  disposed with hydraulic lines, check valves, and sensors. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Generally, a system and method for unlatching and/or latching an RCD or other oilfield device positioned with a latching assembly is disclosed. Also, a system and method for sealing and/or unsealing an RCD or other oilfield device using an active seal is disclosed. The latching assembly may be disposed with a marine riser and/or subsea housing. If there is a marine riser, it is contemplated that the latching assembly be disposed below the tension lines or tension ring supporting the top of the riser from the drilling structure or rig. An RCD may have an inner member rotatable relative to an outer member about thrust and axial bearings, such as RCD Model 7875, available from Weatherford International of Houston, Tex., and other RCDs proposed in the &#39;181, &#39;171 and &#39;774 patents. Although certain RCD types and sizes are shown in the embodiments, other RCD types and sizes are contemplated for all embodiments, including RCDs with different numbers, configurations and orientations of passive seals, and/or RCDs with one or more active seals. It is also contemplated that the system and method may be used to operate these active seals. 
     In  FIG. 1 , riser spool or housing  12  is positioned with marine riser sections ( 4 ,  10 ). Marine riser sections ( 4 ,  10 ) are part of a marine riser, such as disclosed above in the Background of the Invention. Housing  12  is illustrated bolted with bolts ( 24 ,  26 ) to respective marine riser sections ( 4 ,  10 ). Other attachment means are contemplated. An RCD  2  with two passive stripper seals ( 6 ,  8 ) is landed in and latched to housing  12  using latching assemblies, such as first latching piston  14  and second latching piston  18 , both of which may be actuated, such as described in the &#39;837 patent (see FIGS. 2 and 3 of &#39;837 patent). Active packer seal  22  in housing  12 , shown in its noninflated and unsealed position, may be hydraulically expandable to a sealed position to sealingly engage the outside diameter of RCD  2  using the present invention. 
     Remote Operated Vehicle (ROV) subsea control panel  28  may be positioned with housing  12  between protective flanges ( 30 ,  32 ) for operation of hydraulic latching pistons ( 14 ,  18 ) and active packer seal  22 . An ROV  3  containing hydraulic fluid may be sent below sea level to connect with the ROV panel  28  to control operations the housing  12  components. The ROV  3  may be controlled remotely from the surface. In particular, by supplying hydraulic fluid to different components using shutter valves and other mechanical devices, latching pistons ( 14 ,  18 ) and active seal  22  may be operated when practical. Alternatively, or in addition for redundancy, one or more hydraulic lines, such as umbilical line  5 , may be run from the surface to supply hydraulic fluid for remote operation of the housing  12  latching pistons ( 14 ,  18 ) and active seal  22 . Alternatively, or in addition for further redundancy and safety, an accumulator  7  for storing hydraulic fluid may be activated remotely to operate the housing  12  components or store fluids under pressure. It is contemplated that all three means for hydraulic fluid could be provided. It is also contemplated that a similar ROV panel, ROV, hydraulic lines, and/or accumulator may be used with all embodiments of the invention. 
     The RCD  2  outside diameter is smaller than the housing  12  inside diameter or straight thru bore. First retainer member  16  and second retainer member  20  are shown in  FIG. 1  after having been moved from their respective first or unlatched positions to their respective second or latched positions. RCD  2  may have a change in outside diameter that occurs at first retainer member  16 . As shown in  FIG. 1 , the upper outside diameter  9  of RCD  2  may be greater than the lower outside diameter  31  of RCD  2 . Other RCD outside surface configurations are contemplated, including the RCD not having a change in outside diameter. 
     As shown in  FIGS. 1 and 1A , the RCD  2  upper outside diameter  9  above the second retainer member  20  and between the first  16  and second  20  retainer members may have a plurality of vertical grooves  23 . As shown in  FIG. 1A , second retainer member  20  may be a plurality of dogs. First retainer member  16  may also be a plurality of dogs like second retainer member  20 . Retainer members ( 16 ,  20 ) may be segmented locking dogs. Retainer members ( 16 ,  20 ) may each be a split ring or C-shaped member, or they may each be a plurality of segments of split ring or C-shaped members. Retainer members ( 16 ,  20 ) may be biased radially outwardly. Retainer members ( 16 ,  20 ) may each be mechanical interlocking members, such as tongue and groove type or T-slide type, for positive retraction. Other retainer member configurations are contemplated. 
     The vertical grooves  23  along the outside surface of RCD  2  allow for fluid passageways  25  when dogs  20  are in the latched position as shown in  FIG. 1A . The vertical grooves  23  allow for the movement of fluids around the RCD  2  when the RCD  2  is moved in the riser. The vertical grooves  23  are provided to prevent the compression or surging of fluids in the riser below the RCD  2  when RCD  2  is lowered or landed in the riser and swabbing or a vacuum effect when the RCD  2  is raised or retrieved from the riser. 
     Returning to  FIG. 1 , first retainer member  16  blocks the downward movement of the RCD  2  during landing by contacting RCD blocking shoulder  11 , resulting from the change between upper RCD outside diameter  9  and lower RCD outside diameter  31 . Second retainer member  20  has engaged the RCD  2  in a horizontal radial receiving groove  33  around the upper outside diameter  9  of RCD  2  to squeeze or compress the RCD  2  between retainer members ( 16 ,  20 ) to resist rotation. In their second or latched positions, retainer members ( 16 ,  20 ) also may squeeze or compress RCD  2  radially inwardly. It is contemplated that retainer members ( 16 ,  20 ) may be alternatively moved to their latched positions radially inwardly and axially upwardly to squeeze or compress the RCD  2  using retainer members ( 16 ,  20 ) to resist rotation. As can now be understood, the RCD may be squeezed or compressed axially upwardly and downwardly and radially inwardly. In their first or unlatched positions, retainer members ( 16 ,  20 ) allow clearance between the RCD  2  and housing  12 . In their second or latched positions, retainer members ( 16 ,  20 ) block and latchingly engage the RCD  2 , respectively, to resist vertical movement and rotation. The embodiment shown in  FIGS. 1 and 1A  for the outside surface of the RCD  2  may be used for all embodiments shown in all the Figures. 
     While it is contemplated that housing  12  may have a 10,000 psi body pressure rating, other pressure ratings are contemplated. Also, while it is contemplated that the opposed housing flanges ( 30 ,  32 ) may have a 39 inch (99.1 cm) outside diameter, other sizes are contemplated. RCD  2  may be latchingly attached with a 21.250 inch (54 cm) thru bore  34  of marine riser sections ( 4 ,  10 ) with a 19.25 (48.9 cm) inch inside bore  12 A of housing  12 . Other sizes are contemplated. It is also contemplated that housing  12  may be positioned above or be integral with a marine diverter, such as a 59 inch (149.9 cm) inside diameter marine diverter. Other sizes are contemplated. The diverter will allow fluid moving down the drill pipe and up the annulus to flow out the diverter opening below the lower stripper seal  8  and the same active seal  22 . Although active seal  22  is shown below the bearing assembly of the RCD  2  and below latching pistons ( 14 ,  18 ), it is contemplated that active seal  22  may be positioned above the RCD bearing assembly and latching pistons ( 14 ,  18 ). It is also contemplated that there may be active seals both above and below the RCD bearing assembly and latching pistons ( 14 ,  18 ). All types of seals, active or passive, as are known in the art are contemplated. While the active seal  22  is illustrated positioned with the housing  12 , it is contemplated that the seal, active or passive, could instead be positioned with the outer surface of the RCD  2 . 
     In the method, to establish a landing for RCD  2 , which may be an 18.00 inch (45.7 cm) outer diameter RCD, the first retainer member  16  is remotely activated to the latched or loading position. The RCD  2  is then moved into the housing  12  until the RCD  2  lands with the RCD blocking shoulder  11  contacting the first retainer member  16 . The second retainer member  20  is then remotely activated with hydraulic fluid supplied as discussed above to the latched position to engage the RCD receiving groove  33 , thereby creating a clamping force on the RCD  2  outer surface to, among other benefits, resist torque or rotation. In particular, the top chamfer on first retainer member  16  is engaged with the RCD shoulder  11 . When the bottom chamfer on the second retainer member  20  moves into receiving groove  33  on the RCD  2  outer surface, the bottom chamfer “squeezes” the RCD between the two retainer members ( 16 ,  20 ) to apply a squeezing force on the RCD  2  to resist torque or rotation. The active seal  22  may then be expanded with hydraulic fluid supplied as discussed herein to seal against the RCD  2  lower outer surface to seal the gap or annulus between the RCD  2  and the housing  12 . 
     The operations of the housing  12  may be controlled remotely through the ROV fluid supplied to the control panel  28 , with hydraulic line  5  and/or accumulator  7 . Other methods are contemplated, including activating the second retainer member  20  simultaneously with the active seal  22 . Although a bypass channel or line, such as an internal bypass channel  68  shown in  FIG. 2  and an external bypass line  186  shown in  FIG. 4A , is not shown in  FIG. 1 , it is contemplated that a similar external bypass line or internal bypass channel with a valve may be used in  FIG. 1  or in any other embodiment herein. The operation of a bypass line with a valve is discussed in detail below with  FIG. 2 . 
     Back-up or secondary pistons ( 1000 ,  1002 ) may move respective primary pistons ( 14 ,  18 ) to their unlatched positions should the hydraulic system fail to move primary pistons ( 14 ,  18 ). Secondary pistons ( 1000 ,  1002 ) may operate independently of each other. 
     Turning to  FIG. 2 , an RCD  40  with three passive stripper seals ( 41 ,  46 ,  48 ) is positioned with riser spool or housing  72  with first retainer member  56  and second retainer member  60 , both of which are activated by respective hydraulic pistons in respective latching assemblies ( 54 ,  58 ). First retainer member  56  blocks movement of the RCD  40  when blocking shoulder  43  engages retainer member  56  and second retainer member  60  is positioned with RCD receiving formation or groove  45 . The operations of the housing  72  components may be controlled remotely using ROV  61  connected with ROV control panel  62  positioned between flanges ( 74 ,  76 ) and further protected by shielding member  64 . Alternatively, or in addition, as discussed above, housing  74  components may be operated by hydraulic lines and/or accumulators. RCD stripper seal  41  is inverted from the other stripper seals ( 46 ,  48 ) to, among other reasons, resist “suck down” of drilling fluids during a total or partial loss circulation. Such a loss circulation could result in the collapse of the riser if no fluids were in the riser to counteract the outside forces on the riser. For RCD  40  in  FIG. 2 , and for similar RCD stripper seal embodiments in the other Figures, it is contemplated that the two opposing stripper seals, such as stripper seals ( 41 ,  46 ), may be one integral or continuous seal rather than two separate seals. 
     The RCD  40  outside diameter is smaller than the housing  72  inside diameter, which may be 19.25 inches (48.9 cm). Other sizes are contemplated. While the riser housing  72  may have a 10.000 psi body pressure rating, other pressure ratings are contemplated. Retainer members ( 56 ,  60 ) may be a plurality of dogs or a C-shaped member, although other types of members are contemplated. Active seal  66 , shown in an unexpanded or unsealed position, may be expanded to sealingly engage RCD  40  using the present invention. Alternatively, or in addition, an active seal may be positioned above the RCD bearing assembly and latching assemblies ( 54 ,  58 ). Housing  74  is illustrated bolted with bolts ( 50 ,  52 ) to marine riser sections ( 42 ,  44 ). As discussed above, other attachment means are contemplated. While it is contemplated that the opposed housing flanges ( 74 ,  76 ) may have a 45 inch (114.3 cm) outside diameter, other sizes are contemplated. As can now be understood, the RCD  40  may be latchingly attached with the thru bore of housing  72 . It is also contemplated that housing  74  may be positioned with a 59 inch (149.9 cm) inside diameter marine diverter. 
     The system shown in  FIG. 2  is generally similar to the system shown in  FIG. 1 , except for internal bypass channel  68 , which, as stated above, may be used with any of the embodiments. Valve  78 , such as a gate valve, may be positioned in bypass channel  68 . Two end plugs  70  may be used after internal bypass channel  68  is manufactured, such as shown in  FIG. 2 , to seal communication with atmospheric pressure outside the wellbore. Bypass channel  68  with gate valve  78  acts as a check valve in well kick or blowout conditions. Gate valve  78  may be operated remotely. For example, if hazardous weather conditions are forecasted, the valve  78  could be closed with the riser sealable controlled and the offshore rig moved to a safer location. Also, if the riser is raised with the RCD in place, valve  78  could be opened to allow fluid to bypass the RCD  40  and out the riser below the housing  72  and RCD  40 . In such conditions, fluid may be allowed to flow through bypass channel  68 , around RCD  40 , via bypass channel first end  80  and bypass channel second end  82 , thereby bypassing the RCD  40  sealed with housing  72 . Alternatively to internal bypass channel  68 , it is contemplated that an external bypass line, such as bypass line  186  in  FIG. 4A , may be used with  FIG. 2  and any other embodiments. 
     In  FIG. 3A , riser spool or housing  98  is illustrated connected with threaded shafts and nuts  116  to marine riser section  100 . An RCD  90  having a seal assembly  92  is positioned with an RCD running tool  94  with housing  98 . Seal assembly latching formations  118  may be positioned in the J-hook receiving grooves  96  in RCD running tool  94  so that the running tool  94  and RCD  90  are moved together on the drill string through the marine riser and housing  98 . Other attachment means are contemplated as are known in the art. A running tool, such as running tool  94 , may be used to position an RCD with any riser spool or housing embodiments. RCD  90  is landed with housing  98  with first retainer member  106  and squeezed with second retainer member  110 , both of which are remotely actuated by respective hydraulic pistons in respective latching assemblies ( 104 ,  108 ). First retainer member  106  blocks RCD shoulder  105  and second retainer member  110  is positioned with RCD second receiving formation or groove  107 . 
     ROV control panel  114  may be positioned with housing  98  between upper and lower shielding protrusions  112  (only lower protrusion shown) to protect the panel  114 . Other shielding means are contemplated. While it is contemplated that the opposed housing flanges  120  (only lower flange shown) of housing  98  may have a 45 inch (114.3 cm) outside diameter, other sizes are contemplated. The RCD  90  outside diameter is smaller than the housing  98  inside diameter. Retainer members ( 106 ,  110 ) may be a plurality of dogs or a C-shaped member. Active seal  102 , shown in an expanded or sealed position, sealingly engages RCD  102 . After the RCD  90  is sealed as shown in  FIG. 3A , the running tool  94  may be disengaged from the RCD seal assembly  92  and continue moving with the drill string down the riser for drilling operations. Alternatively, or in addition, an active or passive seal may be positioned on RCD  90  instead of on housing  98 , and/or may be positioned both above and below RCD bearing assembly or latching assemblies ( 104 ,  108 ). Alternatively to the embodiment shown in  FIG. 3A , a seal assembly, such as seal assembly  92 , may be positioned above the RCD bearing assembly or latching assemblies ( 104 ,  108 ) to engage an RCD running tool. The alternative seal assembly may be used to either house a seal, such as seal  102 , or be used as the portion of the RCD to be sealed by a seal in a housing, similar to the embodiment shown in  FIG. 3A . 
     Generally, lines and cables extend radially outwardly from the riser, as shown in FIG. 1 of the &#39;171 patent, and male and female members of the lines and cables can be plugged together as the riser sections are joined together. Turning to  FIG. 3B , an exemplary rerouting or placement of these lines and cables is shown external to housing  98  within the design criteria inside diameter  130  as the lines and cables traverse across the housing  98 . Exemplary lines and cables may include 1.875 inch OD multiplex cables  134 , 2.375×2.000 rigid conduit lines  136 , a 5.563×4.5 mud boost line  138 , a 7×4.5 kill line  140 , a 7×4.5 choke line  142 , a 7.5×6 mud return line  144 , and a 7.5×6 seawater fluid power line  146 . Other sizes, lines (such as the discussed umbilical lines) and cables and configurations are contemplated. It is also contemplated that an ROV or accumulator(s) may be used to replace some of the lines and/or conduits. 
     It is contemplated that a marine riser segment would stab the male or pin end of its riser tubular segment lines and cables with the female or box end of a lower riser tubular segment lines and cables. The lines and cables, such as shown in  FIG. 3B , may also be stabbed or plugged with riser tubular segment lines and cables extending radially outward so that they may be plugged together when connecting the riser segments. In other words, the lines and/or cables shown in  FIG. 3B  are rerouted along the vertical elevation profile exterior to housing  98  to avoid housing protrusions, such as panel  114  and protrusion  112 , but the lines and cables are aligned radially outward to allow them to be connected with their respective lines and cables from the adjoining riser segments. Although section  3 B- 3 B is only shown with  FIG. 3A , similar exemplary placement of the ROV panel, lines, and cables as shown in  FIG. 3B  may be used with any of the embodiments. 
     An external bypass line  186  with gate valve  188  is shown and discussed below with  FIG. 4A . Although  FIG. 3A  does not show a bypass line and gate valve, it is contemplated that the embodiment in  FIG. 3A  may have a bypass line and gate valve.  FIG. 3B  shows an exemplary placement of a gate valve  141  with actuator  143  if used with  FIG. 3A . A similar placement may be used for the embodiment in  FIG. 4A  and other embodiments. 
     In  FIGS. 4A-4B , riser spools or housings ( 152 A,  152 B) are bolted between marine riser sections ( 154 ,  158 ) with respective bolts ( 156 ,  160 ). Housing  152 A is bolted with housing  152 B using bolts  157 . A protection member  161  may be positioned with one or more of the bolts  157  (e.g., three openings in the protection member to receive three bolts) to protect an ROV panel, which is not shown. An RCD  150  with three passive stripper seals ( 162 ,  164 ,  168 ) is positioned with riser spools or housings ( 152 A,  152 B) with first retainer member  172 , second retainer member  176 , and third retainer member or seal assembly retainer  182  all of which are activated by respective hydraulic pistons in their respective latching assemblies ( 170 ,  174 ,  180 ). Retainer members ( 172 ,  176 ,  182 ) in housing  152 B as shown in  FIG. 4B  have been moved from their respective first or unlatched positions to their respective second or latched positions. First retainer member  172  blocks RCD shoulder  173  and second retainer member  176  is positioned with RCD receiving formation or groove  175 . The operations of the housing  152 B may be controlled remotely using in any combination an ROV connected with an ROV containing hydraulic fluid and control panel, hydraulic lines, and/or accumulators, all of which have been previously described but not shown for clarity of the Figure. 
     The RCD seal assembly, generally indicated at  178 , for RCD  150  and the RCD running tool  184  are similar to the seal assembly and running tool shown in  FIGS. 10A-10E  and are described in detail below with those Figures. RCD stripper seal  162  is inverted from the other stripper seals ( 164 ,  168 ). Although RCD seal assembly  178  is shown below the RCD bearing assembly and below the first and second latching assemblies ( 170 ,  174 ), a seal assembly may alternatively be positioned above the RCD bearing assembly and the first and second latching assemblies ( 170 ,  174 ) for all embodiments. 
     External bypass line  186  with valve  188  may be attached with housing  152  with bolts ( 192 ,  196 ). Other attachment means are contemplated. A similar bypass line and valve may be positioned with any embodiment. Unlike bypass channel  68  in  FIG. 2 , bypass line  186  in  FIGS. 4A-4B  is external to and releasable from the housings ( 152 A.  152 B). Bypass line  186  with gate valve  188  acts as a check valve in well kick or blowout conditions. Gate valve  188  may be operated remotely. Also, if hazardous weather conditions are forecasted, the valve  188  could be closed with the riser sealable controlled and the offshore rig moved to a safer location. 
     Also, when the riser is raised with the RCD in place, valve  188  could be opened to allow fluid to bypass the RCD  150  and out the riser below the housing  152 B and RCD  150 . In such conditions when seal assembly extrudable seal  198  is in a sealing position (as described below in detail with  FIGS. 10A-10E ), fluid may be allowed to flow through bypass line  186 , around RCD  150 , via bypass line first end  190  and bypass line second end  194 , thereby bypassing RCD  150  sealed with housing  152 B. Alternatively to external bypass line  186 , it is contemplated that an internal bypass channel, such as bypass channel  68  in  FIG. 2 , may be used with  FIGS. 4A-4B  and any other embodiment. 
     Turning to  FIGS. 5A-5B , riser spool or housing  202  is illustrated bolted to marine riser sections ( 204 ,  208 ) with respective bolts ( 206 ,  210 ). An RCD  200  having three passive seals ( 240 ,  242 ,  244 ) and a seal assembly  212  is positioned with an RCD running tool  216  used for positioning the RCD  200  with housing  202 . Seal assembly latching formations  214  may be positioned in the J-hook receiving grooves  218  in RCD running tool  216  and the running tool  216  and RCD  200  moved together on the drill string through the marine riser. RCD  200  is landed with housing  202  with first retainer member  222  and latched with second retainer member  226 , both of which are remotely actuated by respective hydraulic pistons in respective latching assemblies ( 220 ,  224 ). First retainer member  222  blocks RCD shoulder  223  and second retainer member  226  is positioned with RCD receiving formation or groove  225 . 
     Upper  202 A, intermediate  202 B, and lower  202 C active packer seals may be activated using the present invention to seal the annulus between the housing  202  and RCD  200 . Upper seal  202 A and lower active seal  202 C may be sealed together to protect latching assemblies ( 220 ,  224 ). Intermediate active seal  202 B may provide further division or redundancy for seal  202 C. It is also contemplated that lower active seal  202 C may be sealed first to seal off the pressure in the riser below the lower seal  202 C. Upper active seal  202 A may then be sealed at a pressure to act as a wiper to resist debris and trash from contacting latching members ( 220 ,  224 ). Other methods are contemplated. Sensors ( 219 ,  229 ,  237 ) may be positioned with housing  202  between the seals ( 202 A.  202 B,  202 C) to detect wellbore parameters, such as pressure, temperature, and/or flow. Such measurements may be useful in determining the effectiveness of the seals ( 202 A,  202 B,  202 C), and may indicate if a seal ( 202 A,  202 B,  202 C) is not sealing properly or has been damaged or failed. 
     It is also contemplated that other sensors may be used to determine the relative difference in rotational speed (RPM) between any of the RCD passive seals ( 240 ,  242 ,  244 ), for example, seals  240  and  242 . For the embodiment shown in  FIGS. 5A-5B , as well as all other embodiments, a data information gathering system, such as DIGS, provided by Weatherford may be used with a PLC to monitor and/or reduce relative slippage of the sealing elements ( 240 ,  242 ,  244 ) with the drill string. It is contemplated that real time revolutions per minute (RPM) of the sealing elements ( 240 ,  242 ,  244 ) may be measured. If one of the sealing elements ( 240 ,  242 ,  244 ) is on an independent inner member and is turning at a different rate than another sealing element ( 240 ,  242 ,  244 ), then it may indicate slippage of one of the sealing elements with tubular. Also, the rotation rate of the sealing elements can be compared to the drill string measured at the top drive (not shown) or at the rotary table in the drilling floor. 
     The information from all sensors, including sensors ( 219 ,  229 ,  237 ), may be transmitted to the surface for processing with a CPU through an electrical line or cable positioned with hydraulic line  5  shown in  FIG. 1 . An ROV may also be used to access the information at ROV panel  228  for processing either at the surface or by the ROV. Other methods are contemplated, including remote accessing of the information. After the RCD  200  is latched and sealed as shown in  FIG. 5B , the running tool  216  may be disengaged from the RCD  200  and continue moving with the drill string down the riser for drilling operations. 
     ROV control panel  228  may be positioned with housing  200  between two shielding protrusions  230  to protect the panel  228 . The RCD  200  outside diameter is smaller than the housing  202  inside diameter. Retainer members ( 222 ,  226 ) may be a plurality of dogs or a C-shaped member. External bypass line  232  with valve  238  may be attached with housing  202  with bolts ( 234 ,  236 ). Other attachment means are contemplated. Bypass line  232  with gate valve  238  acts as a check valve in well kick or blowout conditions. Valve  238  may be operated remotely. 
     Turning to  FIG. 6A , RCD  250  having a seal assembly, generally designated at  286 , is shown latched in riser spool or housing  252  with first retainer member  256 , second retainer member  260 , and third retainer member or seal assembly retainer  264  of respective latching assemblies ( 254 ,  258 ,  262 ) in their respective second or latched/landed positions. First retainer member  256  blocks RCD shoulder  257  and second retainer member  260  is positioned with RCD receiving formation or groove  259 . An external bypass line  272  is positioned with housing  252 . An ROV panel  266  is disposed with housing  252  between two shielding protrusions  268 . Seal assembly  286  comprises RCD extension or extending member  278 , tool member  274 , retainer receiving member  288 , seal assembly seal  276 , upper or first shear pins  282 , lower or second shear pins  280 , and ratchet shear ring or ratchet shear  284 . Although two upper  282  and two lower  280  shear pins are shown for this and other embodiments, it is contemplated that there may be only one upper  282  and one lower  280  shear pin or that there may be a plurality of upper  282  and lower  280  shear pins of different sizes, metallurgy and shear rating. Other mechanical shearing devices as are known in the art are also contemplated. 
     Seal assembly seal  276  may be bonded with tool member blocking shoulder  290  and retainer receiving member  288 , such as by epoxy. A lip retainer formation in either or both the tool member  274  and retainer receiving member  288  that fits with a corresponding formation(s) in seal  276  is contemplated. This retainer formation, similar to formation  320  shown and/or described with  FIG. 7A , allows seal  276  to be connected with the tool member  274  and/or retainer receiving member  288 . A combination of bonding and mechanical attachment as described above may be used. Other attachment methods are contemplated. The attachment means shown and discussed for use with extrudable seal  276  may be used with any extrudable seal shown in any embodiment. 
     Extrudable seal  276  in  FIG. 6A , as well as all similar extrudable seals shown in all RCD sealing assemblies in all embodiments, may be made from one integral or monolithic piece of material, or alternatively, it may be made from two or more segments of different materials that are formed together with structural supports, such as wire mesh or metal supports. The different segments of material may have different properties. For example, if the seal  276  were made in three segments of elastomers, such as an upper, intermediate, and lower segment when viewed in elevational cross section, the upper and lower segments may have certain properties to enhance their ability to sandwich or compress a more extrudable intermediate segment. The intermediate segment may be formed differently or have different properties that allow it to extrude laterally when compressed to better seal with the riser housing. Other combinations and materials are contemplated. 
     Seal assembly  286  is positioned with RCD running tool  270  with lower shear pins  280  and running tool shoulder  271 . After the running tool is made up in the drill string, the running tool  270  and RCD  250  are moved together from the surface down through the marine riser to housing  252  in the landing position shown in  FIG. 6A . In one method, it is contemplated that before the RCD  250  is lowered into the housing  252 , first retainer member  256  would be in the landing position, and second  260  and third  264  retainer members would be in their unlatched positions. RCD shoulder  257  would contact first retainer member  256 , which would block downward movement. Second retainer member  260  would then be moved to its latched position engaging RCD receiving formation  259 , which, as discussed above, would squeeze the RCD between the first  256  and second  260  retaining members to resist rotation. Third retaining member would then be moved to its latched position with retainer receiving member  288 , as shown in  FIG. 6A . After landing, the seal assembly seal  276  may be extruded as shown in  FIG. 6B . It should be understood that the downward movement of the running tool and RCD may be accomplished using the weight of the drill string. For all embodiments of the invention shown in all the Figures, it is contemplated that a latch position indicator system, such as one of the embodiments proposed in the &#39;837 patent or the &#39;724 publication, may be used to determine whether the latching pistons, such as latching assemblies ( 254 ,  258 ,  262 ) of  FIG. 6A , are in their latched or unlatched positions. It is contemplated that a programmable logic controller (PLC) having a comparator may compare hydraulic fluid values or parameters to determine the positions of the latches. It is also contemplated that an electrical switch system, a mechanical valve system and/or a proximity sensor system may be positioned with a retainer member. Other methods are contemplated. 
     It is contemplated that seal assembly  286  may be detachable from RCD  250 , such as at locations ( 277 A,  277 B). Other attachment locations are contemplated. Seal assembly  286  may be threadingly attached with RCD  250  at locations ( 277 A,  277 B). Other types of connections are contemplated. The releasable seal assembly  286  may be removed for repair, and/or for replacement with a different seal assembly. It is contemplated that the replacement seal assembly would accommodate the same vertical distance between the first retainer member  256 , the second retainer member  260  and the third retainer member  264 . All seal assemblies in all the other embodiments in the Figures may similarly be detached from their RCD. 
       FIG. 6B  shows the setting position used to set or extrude seal assembly seal  276  to seal with housing  252 . To set the extrudable seal  276 , the running tool  270  is moved downward from the landing position shown in  FIG. 6A . This downward motion shears the upper shear pin  282  but not the lower shear pin  280 . This downward movement also ratchets the ratchet shear ring  284  upwardly. As can now be understood, lower shear pin  280  has a higher shear and ratchet force than upper shear pin  282  and ratchet shear ring  284 , respectively, relative to retainer receiving member  288  and then maintains the relative position. Therefore, ratchet shear ring  284  allows the downward movement of the tool member  274 . The running tool  270  pulls the tool member  274  downward. It is contemplated that the force needed to fully extrude seal  276  is less than the shear strength of upper shear pin  282 . 
     When upper shear pin  282  is sheared, there is sufficient force to fully extrude seal  276 . Tool member  274  will move downward after upper shear pin  282  is sheared. Tool member blocking shoulder  292  prevents further downward movement of the tool member  274  when shoulder  292  contacts the upward facing blocking shoulder  294  of RCD extending member  278 . However, it is contemplated that the seal  276  will be fully extruded before tool member  274  blocking shoulder  292  contacts upward facing shoulder  294 . Ratchet shear ring  284  prevents tool member  274  from moving back upwards after tool member  274  moves downwards. 
     Shoulder  290  of tool member  274  compresses and extrudes seal  276  against retainer receiving member  288 , which is held fixed by third retainer member  264 . During setting, ratchet shear ring  284  allows tool member  274  to ratchet downward with minimal resistance and without shearing the ring  284 . After the seal  276  is set as shown in  FIG. 6B , running tool  270  may continue downward through the riser for drilling operations by shearing the lower shear pin  280 . Ratchet shear ring  284  maintains tool member  274  from moving upward after the lower shear pin  280  is sheared, thereby keeping seal assembly seal  276  extruded as shown in  FIG. 6B  during drilling operations. As can now be understood, for the embodiment shown in  FIGS. 6A-6C , the weight of the drill string moves the running tool  270  downward for setting the seal assembly seal  276 . 
     As shown in the  FIG. 6B  view, it is contemplated that shoulder  290  of tool member  274  may be sloped with a positive slope to enhance the extrusion and sealing of seal  276  with housing  252  in the sealed position. It is also contemplated that the upper edge of retainer receiving member  288  that may be bonded with seal  276  may have a negative slope to enhance the extrusion and sealing of seal  276  in the sealed position with housing  252 . The above described sloping of members adjacent to the extrudable seal may be used with all embodiments having an extrudable seal. For  FIG. 6A  and other embodiments with extrudable seals, it is contemplated that if the distance between the outer facing surface of the unextruded seal  276  as it is shown in  FIG. 6A , and the riser housing  252  inner bore surface where the extruded seal  276  makes contact when extruded is 0.75 inch (1.91 cm) to 1 inch (2.54 cm), then 2000 to 3000 of sealing force could be provided. Other distances or gaps and sealing forces are contemplated. It should be understood that the greater the distance or gap, the lower the sealing force of the seal  276 . It should also be understood that the material composition of the extrudable seal will also affect its sealing force. 
       FIG. 6C  shows the housing  252  in the fully released position for removal or retrieval of the RCD  250  from the housing  252 . After drilling operations are completed, the running tool  270  may be moved upward through the riser toward the housing  252 . When running tool shoulder  271  makes contact with tool member  274 , as shown in  FIG. 6C , first, second and third retainer members ( 256 ,  260 ,  264 ) should be in their latched positions, as shown in  FIGS. 6A and 6B . Running tool shoulder  271  then pushes tool member  274  upward, shearing the teeth of ratchet shear ring  284 . As can now be understood, ratchet shear ring  284  allows ratcheting in one direction, but shears when moved in the opposite direction upon application of a sufficient force. Tool member  274  moves upward until upwardly facing blocking shoulder  296  of tool member  274  contacts downwardly facing blocking shoulder  298  of extending member  278 . The pin openings used to hold the upper  282  and lower  280  shear pins should be at substantially the same elevation before the pins were sheared.  FIG. 6C  shows the sheared upper  282  and lower  280  shear pins being aligned. Again, the pins could be continuous in the pin opening or equidistantly spaced as desired and depending on the pin being used. 
     When tool member  274  moves upward, tool member blocking shoulder  290  moves upward, pulling seal assembly seal  276  relative to fixed retainer receiving member  288  retained by the third retainer member  264  in the latched position. The seal  276  is preferably stretched to substantially its initial shape, as shown in  FIG. 6C . The retainer members ( 256 ,  260 ,  264 ) may then be moved to their first or unlatched positions as shown in  FIG. 6C , and the RCD  250  and running tool  270  removed together upward from the housing  252 . 
     Turning to  FIG. 7A , RCD  300  and its seal assembly, generally designated  340 , are shown latched in riser spool or housing  302  with first retainer member  304 , second retainer member  308 , and third retainer member or seal assembly retainer  324  of respective latching pistons ( 306 ,  310 ,  322 ) in their respective second or latched/landed positions. First retainer member  304  blocks RCD shoulder  342  and second retainer member  308  is positioned with RCD second receiving formation  344 . An external bypass line  346  is positioned with housing  302 . An ROV panel  348  is disposed with housing  302  between a shielding protrusion  350  and flange  302 A. Seal assembly  340  comprises RCD extending member  312 , RCD tool member  314 , tool member  330 , retainer receiving member  326 , seal assembly seal  318 , upper shear pins  316 , intermediate shear pins  332 , lower shear pins  334 , ratchet or lock ring  328 , inner split C-ring  352 , and outer split C-ring  354 . Inner C-ring  352  has shoulder  358 . Tool member  314  has downwardly facing blocking shoulders ( 368 ,  360 ). Tool member  330  has upwardly facing blocking shoulders  362  and downwardly facing blocking shoulder  364 . Retainer receiving member  326  has downwardly facing blocking shoulder  366 . Extending member  312  has downwardly facing blocking shoulder  370 . 
     Although two upper  316 , two lower  334  and two intermediate  332  shear pins are shown, it is contemplated that there may be only one upper  316 , one lower  334  and one intermediate  332  shear pin or, as discussed above, that there may be a plurality of upper  316 , lower  334  and intermediate  332  shear pins. Other mechanical shearing devices as are known in the art are also contemplated. Seal assembly seal  318  may be bonded with RCD tool member  314  and retainer receiving member  326 , such as by epoxy. A lip retainer formation  320  in RCD tool member  314  fits with a corresponding formation in seal  318  to allow seal  318  to be pulled by RCD tool member  314 . Although not shown, a similar lip formation may be used to connect the seal  318  with retainer receiving member  326 . A combination of bonding and mechanical attachment as described above may be used. 
     Seal assembly  340  is positioned with RCD running tool  336  with lower shear pins  334 , running tool shoulder  356 , and concentric C-rings ( 352 ,  354 ). The running tool  336  and RCD  300  are moved together from the surface through the marine riser down into housing  302  in the landing position shown in  FIG. 7A . In one method, it is contemplated that before the RCD  300  is lowered into the housing  302 , first retainer member  304  would be in the landed position, and second  308  and third  324  retainer members would be in their unlatched positions. RCD shoulder  342  would be blocked by first retainer member  304  to block the downward movement of the RCD  300 . Second retainer member  308  would then be moved to its latched position engaging RCD receiving formation  344 , which would squeeze the RCD between the first  304  and second  308  retaining members to resist rotation. Third retaining member  324  would then be moved to its latched position with retainer receiving member  326  as shown in  FIGS. 7A-7C . After landing is completed, the seal assembly seal  318  may be set or extruded. 
       FIG. 7B  shows the setting position used to set or extrude seal assembly seal  318  with housing  302 . To set the extrudable seal  318 , the running tool  336  is moved downward from the landing position shown in  FIG. 7A  so that the shoulder  365  of running tool  336  pushes the inner C-ring  352  downward. Inner C-ring  352  contacts blocking shoulder  362  of tool member  330 , and pushes the tool member  330  down until the blocking shoulder  364  of the tool member  330  contacts the blocking shoulder  366  of retainer receiving member  326 , as shown in  FIG. 7B . Outer C-ring  354  then moves inward into groove  358  of inner C-ring  352  as shown in  FIG. 7B . The downward motion of the running tool  336  first shears the lower shear pins  334 , and after inner C-ring  352  urges tool member  330  downward, the upper shear pins  316  are sheared, as shown in  FIG. 7B . The intermediate shear pins  332  are not sheared. As can now be understood, the intermediate shear pins  332  have a higher shear strength than the upper shear pins  316  and lower shear pins  334 . The intermediate shear pin  332  pulls RCD tool member  314  downward until downwardly facing blocking shoulder  368  of RCD tool member  314  contacts upwardly facing blocking shoulder  370  of RCD extending member  312 . The ratchet or lock ring  328  allows the downward ratcheting of tool member  330  relative to retainer receiving member  326 . Like ratchet shear ring  284  of  FIGS. 6A-6C , ratchet or lock ring  328  of  FIGS. 7A-7C  allows ratcheting. However, unlike ratchet shear ring  284  of  FIGS. 6A-6C , ratchet or lock ring  328  of  FIGS. 7A-7C  is not designed to shear when tool member  330  moves upwards, but rather ratchet or lock ring  328  resists the upward movement of the adjacent member to maintain the relative positions. 
     Shoulder  360  of RCD tool member  314  compresses and extrudes seal  318  against retainer receiving member  326 , which is fixed by third retainer member  324 . After the seal  318  is set as shown in  FIG. 7B , running tool  336  may continue downward through the riser for drilling operations. Ratchet or lock ring  328  and intermediate shear pin  332  prevent tool member  330  and RCD tool member  314  from moving upwards, thereby maintaining seal assembly seal  318  extruded as shown in  FIG. 7B  during drilling operations. As can now be understood, for the embodiment shown in  FIGS. 7A-7C , the running tool  336  is moved downward for setting the seal assembly seal  318  and pulled to release. The weight of the drill string may be relied upon for the downward force. 
       FIG. 7C  shows the running tool  336  moved up in the housing  302  after drilling operations for unsetting the seal  318  and thereafter retrieving the RCD  300  from the housing  302 . Running tool shoulder  370  makes contact with inner C-ring  352 . First, second and third retainer members ( 304 ,  308 ,  324 ) are in their latched positions, as shown for first  304  and third  324  retainer members in  FIG. 7C . Inner C-ring  352  shoulders with outer C-ring  354 , outer C-ring  354  shoulders with RCD tool member  314  to shear intermediate shear pins  332 . Ratchet or lock ring  328  maintains tool member  330 . As can now be understood, ratchet or lock ring  328  allows movement of tool member  330 , in one direction, but resists movement in the opposite direction. RCD tool member  314  moves upward until blocking shoulder  361  of RCD tool member  314  contacts blocking shoulder  371  of extending member  312 . The openings used to hold the upper  316  and lower  334  shear pins should be at substantially the same elevation before the pins were started. 
     When RCD tool member  314  moves upward, RCD tool member blocking shoulder  360  moves upward, pulling seal assembly seal  318  with lip retainer formation  320  and/or the bonded connection since retainer receiving member  326  is fixed by the third retainer member  324  in the latched position. The retainer members ( 304 ,  308 ,  324 ) may then be moved to their first or unlatched positions, and the RCD  300  and running tool  336  together pulled upwards from the housing  302 . 
     Turning to  FIG. 8A , RCD  380  and its seal assembly, generally indicated  436 , are shown latched in riser spool or housing  382  with first retainer member  386 , second retainer member  390 , and third retainer member or seal assembly retainer  398  of respective latching pistons ( 388 ,  392 ,  400 ) in their respective second or latched positions. First retainer member  386  blocks RCD shoulder  438  and second retainer member  390  is positioned with RCD receiving formation  440 . An external bypass line  384  is positioned with housing  382 . A valve may be positioned with line  384  and any additional bypass line. An ROV panel  394  is disposed with housing  382  between a shielding protrusion  396  and a protection member  381  positioned with flange  382 A, similar to protection member  161  in  FIG. 4A . Returning to  FIG. 8A , seal assembly  436  comprises RCD extending member  402 , tool member  418 , retainer receiving member  416 , seal assembly seal  404 , upper shear pins  422 , lower shear pins  408 , ratchet lock ring  420 , lower shear pin retainer ring or third C-ring  410 , inner or first C-ring  428 , and outer or second C-ring  430 . Inner C-ring  428  has groove  432  for seating outer C-ring  430  when running tool  412  is moved downward from its position shown on the left side of the break line in  FIG. 8A , as will be described in detail with  FIG. 8C . Tool member  418  has blocking shoulder  426 . Retainer receiving member  416  has blocking shoulder  424  and loss motion connection or groove  434  for a loss motion connection with third retainer member  398  in its latched position, as shown in  FIG. 8A . Extending member  402  has a lip retainer formation  406  for positioning with a corresponding formation on seal  404 . 
     Although two upper  422  and two lower  408  shear pins are shown for this embodiment, it is contemplated that there may be only one upper  422  and one lower  408  shear pin or, as discussed above, that there may be a plurality of upper  422  and lower  408  shear pins for this embodiment of the invention. Other mechanical shearing devices as are known in the art are also contemplated. Seal assembly seal  404  may be bonded with extending member  402  and retainer receiving member  416 , such as by epoxy. A lip retainer formation  406  in RCD extending member  402  fits with a corresponding formation in seal  404  to allow seal  404  to be pulled by extending member  402 . Although not shown, a similar lip formation may be used to connect the seal  404  with retainer receiving member  416 . A combination of bonding and mechanical attachment as described above may be used. Other attachment methods are contemplated. 
     Seal assembly  436  is positioned with RCD running tool  412  with lower shear pins  408  and third C-ring  410 , running tool shoulder  414 , and concentric inner and outer C-rings ( 428 ,  430 ). The running tool  412  and RCD  380  are moved together from the surface through the marine riser down into housing  382  in the position landing shown on the right side of the break line in  FIG. 8A . In one method, it is contemplated that before the RCD  380  is lowered into the housing  382 , first retainer member  386  would be in the latched or landing position, and second  390  and third  398  retainer members would be in their unlatched positions. RCD shoulder  438  would contact first retainer member  386 , which would block the downward movement of the RCD  380 . Second retainer member  390  would then be moved to its latched position engaging RCD receiving formation  440  to squeeze the RCD  380  between the first retaining members  386  and second retaining members  390  to resist rotation. Third retaining member  398  would then be moved to its latched position with retainer receiving member  416 , as shown in  FIG. 8A . 
     On the left side of the break line in  FIG. 8A , the running tool  412  has moved upwards, shearing the lower shear pins  408 . Shoulder  426  of tool member  418  pushes lower shear pin retainer C-ring  410  downward to slot  413  of running tool  412 . C-ring  410  has an inward bias and contracted inward from its position shown on the right side of the break line due to the diameter of the running tool  413 . Blocking shoulder  414  of running tool  412  has made contact with blocking shoulder  424  of retainer receiving member  416 . 
       FIG. 8B  shows the setting position to mechanically set or extrude seal assembly seal  404  with housing  382 . To set the extrudable seal  404 , the running tool  412  is moved upward from the landing position, shown on the right side of  FIG. 8A , to the position shown on the left side of  FIG. 8A . The blocking shoulder  414  of running tool  412  pushes the retainer receiving member  416  upward. Loss motion groove  434  of retainer receiving member  416  allows retainer receiving member  416  to move upward until it is blocked by downwardly facing blocking shoulder  426  of tool member  418  and the upward facing shoulder  427  of retainer receiving member  46  as shown in  FIG. 8C . The ratchet or lock ring  420  allows upward ratcheting of retainer receiving member  416  with tool member  418 . It should be understood that the tool member  418  does not move downwards to set the seal  404  in  FIG. 8C . Like the ratchet or lock ring  328  of  FIGS. 7A-7C , ratchet or lock ring  420  maintains the positions of its respective members. 
     Retainer receiving member  416  compresses and extrudes seal  404  against RCD extending member  402 , which is latched with held by first retainer member  386 . After the seal  404  is set as shown in  FIG. 8B , running tool  412  may begin moving downward as shown in  FIG. 8C  through the riser for drilling operations. Ratchet or lock ring  420  maintains retainer receiving member  416  from moving downwards, thereby keeping seal assembly seal  404  extruded as shown in  FIG. 8B  during drilling operations. As can now be understood, for the embodiment shown in  FIGS. 8A-8E , unlike the embodiments shown in  FIGS. 6A-6C and 7A-7C , the running tool  412  is moved upwards for extruding the seal assembly seal  404 . 
     In  FIG. 8C , the running tool  412  has begun moving down through the housing  382  from its position in  FIG. 8B  to begin drilling operations after seal  404  has been extruded. RCD  380  remains latched with housing  382 . Running tool shoulder  440  makes contact with inner C-ring  428  pushing it downwards. Outer C-ring  430 , which has a radially inward bias, moves from its concentric position inward into groove  432  in inner C-ring  428 , and inner C-ring  428  moves outward enough to allow running tool shoulder  440  to move downward past inner C-ring  428 . Running tool may then move downward with the drill string for drilling operations. 
       FIG. 8D  shows RCD running tool  412  returning from drilling operations and moving upwards into housing  382  for the RCD  380  retrieval process. Shoulder  442  of running tool  412  shoulders inner C-ring  428 , as shown in  FIG. 8D .  FIG. 8E  shows the seal assembly  436  and housing  382  in the RCD retrieval position. The first retainer members  386  and second retainer members  390  are in their first or unlatched positions. Running tool  412  moves upwards and running tool shoulder  442  shoulders inner C-ring  428  upwards, which shoulders outer C-ring  430 . Outer C-ring  430  then shoulders unlatched RCD extending member  402  upwards. RCD  380  having RCD extending member  402  may move upwards since first  386  and second  390  retainer members are unlatched. Lip formation  406  of extending member  402  pulls seal  404  upwards. Seal  404  may also be bonded with extending member  402 . Retainer receiving member  416  remains shouldered against third retainer  398  in the latched position. It is contemplated that seal  404  may also be bonded with retainer receiving member  416 , and/or may also have a lip formation connection similar to formation  406  on extending member  402 . In all embodiments of the invention, when retrieving or releasing an RCD from the housing, the running tool is pulled or moves upwards into the housing. 
     Turning to  FIG. 9A , RCD  444  and its seal assembly  466  are shown latched in riser spool or housing  446  with first retainer member  448 , second retainer member  452 , and third retainer member or seal assembly retainer member  462  of respective latching pistons ( 450 ,  454 ,  464 ) in their respective second or latched positions. First retainer member  448  blocks RCD shoulder  492  and second retainer member  452  is positioned with RCD receiving formation  494 . An external bypass line  456  is positioned with housing  446 . An ROV panel  458  is disposed with housing  446  between a shouldering protrusion  460  and flange  446 A. Seal assembly  466  comprises RCD or extending member  470 , RCD tool member  490 , tool member  482 , retainer receiving member  496 , seal member  476 , seal assembly seal  480 , upper shear pins  472 , intermediate shear pins  474 , lower shear pins  484 , seal assembly dog  478 , upper lock ring ratchet or lock ring  488 , lower ratchet or lock ring  486 , inner or first C-ring  498 , and outer segments  500  with two garter springs  502 . It is contemplated that there may be a plurality of segments  500  held together radially around inner C-ring  498  by garter springs  502 . Segments  500  with garter springs  502  are a radially enlargeable member urged to be contracted radially inward. It is also contemplated that there may be only one garter spring  502  or a plurality of garter springs  502 . It is also contemplated that an outer C-ring may be used instead of outer segments  500  with garter springs  502 . An outer C-ring may also be used with garter springs. Inner C-ring  498  is disposed between running tool shoulders ( 518 ,  520 ). Inner C-ring  498  has groove  504  for seating outer segments  500  when running tool  468  is moved downward from its position in  FIG. 9A , as will be described in detail with  FIG. 9C . 
     Upper ratchet or lock ring  488  is disposed in groove  524  of RCD extending member  470 . Although two upper  472 , two lower  484  and two intermediate  474  shear pins are shown for this embodiment, it is contemplated that there may be only one upper shear pin  472 , one lower shear pin  484  and one intermediate sheer pin  474  shear pin or, as discussed above, that there may be a plurality of upper  472 , lower  484  and intermediate  474  shear pins. Other mechanical shearing devices as are known in the art are also contemplated. Seal assembly seal  480  may be bonded with seal member  476  and retainer receiving member  496 , such as by epoxy. A lip retainer formation  506  in seal member  476  fits with a corresponding formation in seal  480  to allow seal  480  to be pulled by seal member  476 , as will be described below in detail with  FIG. 9E . Although not shown, a similar lip formation may be used to connect the seal  480  with retainer receiving member  496 . A combination of bonding and mechanical attachment, as described above, may be used. Other attachment methods are contemplated. 
     Seal assembly, generally indicated as  466 , is positioned with RCD running tool  468  with lower shear pins  484 , running tool shoulder  508 , inner C-ring  498 , and segments  500  with garter springs  502 . The running tool  468  and RCD  444  are moved together from the surface through the marine riser down into housing  446  in the landing position shown in  FIG. 9A . In one method, it is contemplated that before the RCD  444  is lowered into the housing  446 , first retainer member  448  would be in the landing position, and second  452  and third  462  retainer members would be in their unlatched positions. RCD shoulder  492  would contact first retainer member  448  to block the downward movement of the RCD  444 . Second retainer member  452  would then be moved to its latched position engaging RCD receiving formation  494 , which would squeeze the RCD between the first  448  and second  452  retaining members to resist rotation. Third retaining member  462  would then be moved to its latched position with retainer receiving member  496  as shown in  FIG. 9A . 
       FIG. 9B  shows the first stage of the setting position used to mechanically set or extrude seal assembly seal  480  with housing  446 . To set the extrudable seal  480 , the running tool  468  is moved downward from the landing position shown in  FIG. 9A . The lower shear pin  484  pulls tool member  482  downward with running tool  468 . Tool member shoulder  518  also shoulders inner C-ring  498  downward relative to outer segments  500  held with garter springs  502 . Similar to ratchet or lock ring  328  of  FIGS. 7A-7C , lower ratchet or lock ring  486  allows the downward movement of tool member  482  while resisting the upward movement of the tool member  482 . Similarly, upper ratchet or lock ring  488  allows the downward movement of RCD tool member  490  while resisting the upward movement of the RCD tool member  490 . However, as will be discussed below with  FIG. 9D , upper ratchet or lock ring  488  is positioned in slot  524  of extending member  470 , allowing movement of upper ratchet or lock ring  488 . 
     RCD tool member  490  is pulled downward by intermediate shear pins  474  disposed with tool member  482 . The downward movement of tool member  482  shears upper shear pins  472 . As can now be understood, the shear strength of upper shear pins  472  is lower than the shear strengths of intermediate shear pins  474  and lower shear pins  484  shear pins. Tool member  482  moves downward until its downwardly facing blocking shoulder  514  contacts retainer receiving member upwardly facing blocking shoulder  516 . Seal assembly retaining dog  478  pulls seal member  476  downward until its downwardly facing shoulder  510  contacts extending member upwardly facing shoulder  512 . Dog  478  may be a C-ring with radially inward bias. Other devices are contemplated. Seal assembly retainer  462  is latched, fixing retainer receiving member  496 . Seal assembly seal  480  is extruded or set as shown in  FIG. 9B . Lower ratchet or lock ring  486  resists tool member  482  from moving upwards, and dog  478  resists seal member  476  from moving upwards, thereby maintaining seal assembly seal  480  extruded as shown in  FIG. 9B  during drilling operations. 
       FIG. 9C  shows the final stage of setting the seal  480 . Running tool  468  is moved downward from its position in  FIG. 9B  using the weight of the drill string to shear lower shear pin  484 . As can now be understood, lower shear pin  484  has a lower shear strength than intermediate shear pin  474 . RCD running tool shoulder  518  pushes inner C-ring  498  downward and outer segments  500  may move inward into groove  504  of inner C-ring  498 , as shown in  FIG. 9C . Running tool  468  may then proceed downward with the drill string for drilling operations, leaving RCD  444  sealed with the housing  446 . As can now be understood, for the embodiment shown in  FIGS. 9A-9E , the running tool  468  is moved downward for setting the seal assembly seal  480 . The weight of the drill string may be relied upon for the downward force. 
       FIG. 9D  shows the running tool  468  moving up in the housing  446  after drilling operations for the first stage of unsetting or releasing the seal  480  and thereafter retrieving the RCD  444  from the housing  446 . Running tool shoulder  520  shoulders inner C-ring  498 . Third retainer member  462  is in its latched position. Inner C-ring  498  shoulders outer segments  500  upwards by the shoulder in groove  504 , and outer segments  500  shoulders RCD tool member  490  upwards, shearing intermediate shear pins  474 . Upper ratchet or lock ring  488  moves upwards in slot  524  of RCD extending member  470  until it is blocked by shoulder  526  of extending member  470 . Seal assembly retainer dog  478  is allowed to move inwardly or retracts into slot  522  of RCD tool member  490 . Although not shown in  FIGS. 9D-9E , first  448  retainer member and second retainer member  452 , shown in  FIG. 9A , are moved into their first or unlatched positions. It is also contemplated that both or either of first retainer member  448  and second retainer member  452  may be moved to their unlatched positions before the movement of the running tool  468  shown in  FIG. 9D . 
     Turning to  FIG. 9E , the final stage for unsealing seal  480  is shown. Running tool  468  is moved upwards from its position in  FIG. 9D , and running tool shoulder  520  shoulders inner C-ring  498  upwards. Inner C-ring  498  shoulders outer segments  500  disposed in slot  504  of inner C-ring  498  upwards. Outer segments  500  shoulders RCD tool member  490  upwards. Since upper ratchet or lock ring  488  had previously contacted shoulder  526  of extension member  470  in  FIG. 9D , upper ratchet or ring  488  now shoulders RCD extending member  470  upwards by pushing on shoulder  526 . RCD extending member  470  may move upwards with RCD  444  since first retaining member  448  and second retaining member  452  are in their unlatched positions. Upwardly facing shoulder  512  of extending member  470  pulls downwardly facing shoulder  510  of seal member  476  upwards, and seal member  476 , in turn, stretches seal  480  upwards through lip formation  506  and/or bonding with seal  480 . 
     Third retainer member  462  maintains retainer receiving member  496  and the one end of seal  480  fixed, since seal  480  is bonded and/or mechanically attached with retainer receiving member  496 . Seal assembly retainer dog  478  moves along slot  522  of RCD tool member  490 . Seal  480  is preferably stretched to substantially its initial shape, as shown in  FIG. 9E , at which time the openings in running tool  468  and tool member  482  for holding lower shear pins  484 , which was previously sheared, are at the same elevation when the lower shear pin  484  was not sheared. Seal assembly retainer member or third retainer member  462  may then be moved to its first or unlatched position, allowing RCD running tool  468  to lift the RCD  444  to the surface. 
     Turning to  FIG. 10A , RCD  530  and its seal assembly  548  are shown latched in riser spool or housing  532  with first retainer member  536 , second retainer member  540 , and third retainer member  544  of respective latching pistons ( 538 ,  542 ,  546 ) in their respective second or latched positions. First retainer member  536  blocks RCD shoulder  582  and second retainer member  540  is positioned with RCD receiving formation  584 . An external bypass line  534  is positioned with housing  532 . Seal assembly, generally indicated at  548 , comprises RCD extending member  550 , RCD tool member  580 , tool member  560 , retainer receiving member  554 , seal assembly seal  570 , upper shear pins  578 , lower shear pins  558 , lower shear pin holding segments  556  with garter springs  586 , ratchet or lock ring  562 , inner C-ring  564 , outer segments  566  with garter springs  568 , and seal assembly retaining dog  576 . It is contemplated that C-rings may be used instead of segments ( 566 ,  556 ) with respective garter springs ( 568 ,  586 ), or that C-rings may be used with garter springs. Tool member shoulder  600  shoulders with lower shear pin segments  556 . Inner C-ring  564  has groove  572  for seating outer segments  566  when running tool  552  is moved as described with and shown in  FIG. 10C . Inner C-ring  562  shoulders with running tool shoulder  588 . Retainer receiving member  554  has a blocking shoulder  590  in the loss motion connection or groove  592  for a loss motion connection with third retainer member  544  in its latched position, as shown in  FIG. 10A . 
     Although two upper shear pins  578  and two lower shear pins  558  are shown, it is contemplated that there may be only one upper shear pin  578  and one lower shear pin  558  or, as discussed above, that there may be a plurality of upper shear pins  578  and lower shear pins  558 . Other mechanical shearing devices as are known in the art are also contemplated. Seal assembly seal  570  may be bonded with extending member  550  and retainer receiving member  554 , such as by epoxy. A lip retainer formation  574  in RCD extending member  550  fits with a corresponding formation in seal  570  to allow seal  570  to be pulled by extending member  550 . Although not shown, a similar lip formation may be used to connect the seal  570  with retainer receiving member  554 . A combination of bonding and mechanical attachment as described above may be used. Other attachment methods are contemplated. 
     Seal assembly, generally indicated at  548 , is positioned with RCD running tool  552  with lower shear pins  558  and lower shear pin segments  556 , running tool shoulder  588 , inner C-ring  564 , and outer segments  566  with garter springs  568 . Lower shear pin segments  556  are disposed on running tool surface  594 , which has a larger diameter than adjacent running tool slot  596 . The running tool  552  and RCD  530  are moved together from the surface through the marine riser down into housing  532  in the landing position shown in  FIG. 10A . In one method, it is contemplated that before the RCD  530  is lowered into the housing  532 , first retainer member  536  would be in the landing position, and second  540  and third  544  retainer members would be in their unlatched positions. RCD shoulder  582  would be blocked by first retainer member  536 , which would block downward movement of the RCD  530 . Second retainer member  540  would then be moved to its latched position engaging RCD receiving formation  584 , which would squeeze the RCD  530  between the first  536  and second  540  retaining members to resist rotation. Third retaining member  544  would then be moved to its latched position with retainer receiving member  554  in loss motion connection or groove  592  as shown in  FIG. 10A . After landing is completed, the process of extruding the seal assembly seal  570  may begin as shown in  FIGS. 10B-10C . 
     In  FIG. 10B , the running tool  552  has moved upwards, and blocking shoulder  600  of tool member  560  has pushed lower shear pin holding segments  556  downward from running tool surface  594  to running tool slot  596 . Garter springs  586  contract segments  556  radially inward. The lower shear pin  558  has been sheared by the movement of segments  556 . 
     To continue setting or extruding seal  570 , the running tool  552  is further moved upwards from its position shown in  FIG. 10B . The seal  570  final setting position is shown in  FIG. 10C , but in  FIG. 10C  the running tool  552  has already been further moved upwards from its position in  FIG. 10B , and then is shown moving downwards in  FIG. 10C  with the drill string for drilling operations. To set the seal  570  as shown in  FIG. 10C , the running tool  552  moves up from its position in  FIG. 10B , and running tool shoulder  598  shoulders retainer receiving member  554  upwards until blocked by shoulder  600  of tool member  560 . The ratchet or lock ring  562  allows the unidirectional upward movement of retainer receiving member  554  relative to tool member  560 . Like the ratchet or lock ring  328  of  FIGS. 7A-7C , ratchet or lock ring  562  resists the upward movement of the tool member  560 . 
     Loss motion connection or groove  592  of retainer receiving member  554  allows retainer receiving member  554  to move upward until it is blocked by the third retainer  544  contacting shoulder  590  at one end of groove  592 , as shown in  FIG. 10C . Retainer receiving member  554  mechanically compresses and extrudes seal  570  against RCD extending member  550 , which, as shown in  FIG. 10A , is latchingly fixed by first retainer member  536 . After the seal  570  is set with the upward movement of the running tool  552  from its position shown in  FIG. 10B , inner C-ring  564  and outer segments  566  will still be concentrically disposed as shown in  FIG. 10B . Running tool  552  may then be moved downward with the drill string for drilling operations. With this downward movement, running tool shoulder  588  shoulders inner C-ring  564  downwards, and outer segments  566  with their garter springs  568  will move inward into groove  572  in inner C-ring  564  in the position shown in  FIG. 10C . The running tool  552  then, as described above, continues moving down out of the housing  530  for drilling operations. Ratchet or lock ring  562  resists retainer receiving member  554  from moving downwards, thereby maintaining seal assembly seal  570  extruded, as shown in  FIG. 10C  during the drilling operations. As can now be understood, for the embodiment shown in  FIGS. 10A-10E , like the embodiment shown in  FIGS. 8A-8E . and unlike the embodiments shown in  FIGS. 6A-6C, 7A-7C and 9A-9E , the running tool is moved upwards for mechanically setting or extruding the seal assembly seal. 
       FIG. 10D  shows RCD running tool  552  moving upwards into housing  532  returning upon drilling operations for the beginning of the RCD  530  retrieval process. When blocking shoulder  602  of running tool  552  shoulders inner C-ring  564 , as shown in  FIG. 10D , the first retainer members  536  and second retainer members  540  are preferably in their first or unlatched positions. It is also contemplated that the retainer members  536 ,  540  may be unlatched after the running tool  552  is in the position shown in  FIG. 10D  but before the position shown in  FIG. 10E . Shoulder  612  of inner C-ring groove  572  shoulders outer segments  566  upward. Outer segments  566 , in turn, shoulders RCD tool member  580  upwards. RCD tool member  580 , in turn, moves upward until its upwardly facing blocking shoulder  608  is blocked by downwardly facing shoulder  610  of RCD extending member  550 . The upward movement of RCD tool member  580 , as shown in  FIG. 1  OD, allows the retraction of seal assembly dog  576  into slot  606 . 
     Turning now to  FIG. 10E , running tool  552  moves further upward from its position in  FIG. 10D  continuing to shoulder inner C-ring  564  upward with running tool shoulder  602 . Outer segments  566  continue to shoulder RCD tool member  580  so seal assembly dog  576  moves along slot  606  until contacting shoulder  604  at the end of the RCD tool member slot  606 . Dog  576  may be a C-ring or other similar device with a radially inward bias. Blocking shoulder  608  of RCD tool member  580  shoulders blocking shoulder  610  of RCD extending member  550  upwards. RCD  530  having RCD extending member  550  moves upward since first retainer members  536  and second retainer members  540  are unlatched. Lip formation  574  of extending member  550  pulls and stretches seal  570  upward. Seal  570  may also be bonded with extending member  550 . Retainer receiving member  554  shouldered at shoulder  590  is blocked by third retainer  544  in the latched position. It is contemplated that retainer receiving member  554  may also have a lip formation similar to formation  574  on extending member  550  and be bonded for further restraining both ends of seal  570 . After seal  570  is unset or released, third retainer member  544  may be moved to its unlatched position and the running tool  552  moved upward to the surface with the RCD  530 . 
     For all embodiments in all of the Figures, it is contemplated that the riser spool or housing with RCD disposed therein may be positioned with or adjacent the top of the riser, in any intermediate location along the length of the riser, or on or adjacent the ocean floor, such as over a conductor casing similar to shown in the &#39;774 patent or over a BOP stack similar to shown in FIG. 4 of the &#39;171 patent. 
     In  FIG. 11 , RCD  100 ′ is disposed in a single hydraulic latch assembly  240 ′.  FIG. 11  is a cross-section view of an embodiment of a single diverter housing section, riser section, or other applicable wellbore tubular section (hereinafter a “housing section”), and a single hydraulic latch assembly to better illustrate the rotating control device  100 ′. As shown in  FIG. 11 , a latch assembly separately indicated at  210 ′ is bolted to a housing section  200 ′ with bolts  212 A′ and  212 B′. Although only two bolts  212 A′ and  212 B′ are shown in  FIG. 11 , any number of bolts and any desired arrangement of bolt positions can be used to provide the desired securement and sealing of the latch assembly  210 ′ to the housing section  200 ′. As shown in  FIG. 11 , the housing section  200 ′ has a single outlet  202 ′ for connection to a diverter conduit  204 ′, shown in phantom view; however, other numbers of outlets and conduits can be used with diverter conduits  115 ′ and  117 ′. Again, this conduit  204 ′ can be connected to a choke. The size, shape, and configuration of the housing section  200 ′ and latch assembly  210 ′ are exemplary and illustrative only, and other sizes, shapes, and configurations can be used to allow connection of the latch assembly  210 ′ to a riser. In addition, although the hydraulic latch assembly is shown connected to a nipple, the latch assembly can be connected to any conveniently configured section of a wellbore tubular or riser. 
     A landing formation  206 ′ of the housing section  200 ′ engages a shoulder  208 ′ of the rotating control device  100 ′, limiting downhole movement of the rotating control device  100 ′ when positioning the rotating control device  100 ′. The relative position of the rotating control device  100 ′ and housing section  200 ′ and latching assembly  210 ′ are exemplary and illustrative only, and other relative positions can be used. 
       FIG. 11  shows the latch assembly  210 ′ latched to the rotating control device  100 ′. A retainer member  218 ′ extends radially inwardly from the latch assembly  210 ′, engaging a latching formation  216 ′ in the rotating control device  100 ′, latching the rotating control device  100 ′ with the latch assembly  210 ′ and therefore with the housing section  200 ′ bolted with the latch assembly  210 ′. In some embodiments, the retainer member  218 ′ can be “C-shaped”, that can be compressed to a smaller diameter for engagement with the latching formation  216 ′. However, other types and shapes of retainer rings are contemplated. In other embodiments, the retainer member  218 ′ can be a plurality of dog, key, pin, or slip members, spaced apart and positioned around the latch assembly  210 ′. In embodiments where the retainer member  218 ′ is a plurality of dog or key members, the dog or key members can optionally be spring-biased. Although a single retainer member  218 ′ is described herein, a plurality of retainer members  218 ′ can be used. The retainer member  218 ′ has a cross section sufficient to engage the latching formation  216 ′ positively and sufficiently to limit axial movement of the rotating control device  100 ′ and still engage with the latch assembly  210 ′. An annular piston  220 ′ is shown in a first position in  FIG. 11 , in which the piston  220 ′ blocks the retainer member  218 ′ in the radially inward position for latching with the rotating control device  100 ′. Movement of the piston  220 ′ from a second position to the first position compresses or moves the retainer member  218 ′ radially inwardly to the engaged or latched position shown in  FIG. 11 . Although shown in  FIG. 11  as an annular piston  220 ′, the piston  220 ′ can be implemented, for example, as a plurality of separate pistons disposed about the latch assembly  210 ′. 
     When the piston  220 ′ moves to a second position, the retainer member  218 ′ can expand or move radially outwardly to disengage from and unlatch the rotating control device  100  from the latch assembly  210 ′. The retainer member  218 ′ and latching formation  216 ′ can be formed such that a predetermined upward force on the rotating control device  100 ′ will urge the retainer member radially outwardly to unlatch the rotating control device  100 ′. A second or auxiliary piston  222 ′ can be used to urge the first piston  220 ′ into the second position to unlatch the rotating control device  100 ′, providing a backup unlatching capability. The shape and configuration of pistons  220 ′ and  222 ′ are exemplary and illustrative only, and other shapes and configurations can be used. 
     Hydraulic ports  232 ′ and  234 ′ and corresponding gun-drilled passageways allow hydraulic actuation of the piston  220 ′. Increasing the relative pressure on port  232 ′ causes the piston  220 ′ to move to the first position, latching the rotating control device  100 ′ to the latch assembly  210 ′ with the retainer member  218 ′. Increasing the relative pressure on port  234 ′ causes the piston  220 ′ to move to the second position, allowing the rotating control device  100 ′ to unlatch by allowing the retainer member  218 ′ to expand or move and disengage from the rotating control device  100 ′. Connecting hydraulic lines (not shown in the figure for clarity) to ports  232 ′ and  234 ′ allows remote actuation of the piston  220 ′. 
     The second or auxiliary annular piston  222 ′ is also shown as hydraulically actuated using hydraulic port  230 ′ and its corresponding gun-drilled passageway. Increasing the relative pressure on port  230 ′ causes the piston  222 ′ to push or urge the piston  220 ′ into the second or unlatched position, should direct pressure via port  234 ′ fail to move piston  220 ′ for any reason. 
     The hydraulic ports  230 ′,  232 ′ and  234 ′ and their corresponding passageways shown in  FIG. 11  are exemplary and illustrative only, and other numbers and arrangements of hydraulic ports and passageways can be used. In addition, other techniques for remote actuation of pistons  220 ′ and  222 ′, other than hydraulic actuation, are contemplated for remote control of the latch assembly  210 ′. 
     Thus, the rotating control device illustrated in  FIG. 11  can be positioned, latched, unlatched, and removed from the housing section  200 ′ and latch assembly  210 ′ without sending personnel below the rotary table into the moon pool to manually connect and disconnect the rotating control device  100 ′. 
     An assortment of seals is used between the various elements described herein, such as wiper seals and O-rings, known to those of ordinary skill in the art. For example, each piston  220 ′ preferably has an inner and outer seal to allow fluid pressure to build up and force the piston in the direction of the force. Likewise, seals can be used to seal the joints and retain the fluid from leaking between various components. In general, these seals will not be further discussed herein. 
     For example, seals  224 A′ and  224 B′ seal the rotating control device  100 ′ to the latch assembly  210 ′. Although two seals  224 A′ and  224 B′ are shown in  FIG. 11 , any number and arrangement of seals can be used. In one embodiment, seals  224 A′ and  224 B′ are Parker Polypak®@¼-inch cross section seals from Parker Hannifin Corporation. Other seal types can be used to provide the desired sealing. 
     In  FIG. 12 , RCD  100 ′ is disposed in a dual hydraulic latch assembly  300 ′.  FIG. 12  illustrates another embodiment of a latch assembly, generally indicated at  300 ′, that is a dual hydraulic latch assembly. As with the single latch assembly  210 ′ embodiment illustrated in  FIG. 11 , piston  220 ′ compresses or moves retainer member  218 ′ radially inwardly to latch the rotating control device  100 ′ to the latch assembly  300 ′. The retainer member  218 ′ latches the rotating control device  100 ′ in a latching formation, shown as an annular groove  320 ′, in an outer housing of the rotating control device  100 ′ in  FIG. 12 . The use and shape of annular groove  320 ′ is exemplary and illustrative only and other latching formations and formation shapes can be used. The dual hydraulic latch assembly includes the pistons  220 ′ and  222 ′ and retainer member  218 ′ of the single latch assembly embodiment of  FIG. 11  as a first latch subassembly. The various embodiments of the dual hydraulic latch assembly discussed below as they relate to the first latch subassembly can be equally applied to the single hydraulic latch assembly of  FIG. 11 . 
     In addition to the first latch subassembly comprising the pistons  220 ′ and  222 ′ and the retainer member  218 ′, the dual hydraulic latch assembly  300 ′ embodiment illustrated in  FIG. 12  provides a second latch subassembly comprising a third piston  302 ′ and a second retainer member  304 ′. In this embodiment, the latch assembly  300 ′ is itself latchable to a housing section  310 ′, shown as a riser nipple, allowing remote positioning and removal of the latch assembly  300 ′. In such an embodiment, the housing section  310 ′ and dual hydraulic latch assembly  300 ′ are preferably matched with each other, with different configurations of the dual hydraulic latch assembly implemented to fit with different configurations of the housing section  310 ′. A common embodiment of the rotating control device  100 ′ can be used with multiple dual hydraulic latch assembly embodiments; alternately, different embodiments of the rotating control device  100 ′ can be used with each embodiment of the dual hydraulic latch assembly  300 ′ and housing section  310 ′. 
     As with the first latch subassembly, the piston  302 ′ moves to a first or latching position. However, the retainer member  304 ′ instead expands radially outwardly, as compared to inwardly, from the latch assembly  300 ′ into a latching formation  311 ′ in the housing section  310 ′. Shown in  FIG. 12  as an annular groove  311 ′, the latching formation  311 ′ can be any suitable passive formation for engaging with the retainer member  304 ′. As with pistons  220 ′ and  222 ′, the shape and configuration of piston  302 ′ is exemplary and illustrative only and other shapes and configurations of piston  302 ′ can be used. In some embodiments, the retainer member  304 ′ can be “C-shaped” that can be expanded to a larger diameter for engagement with the latching formation  311 ′. However, other types and shapes of retainer rings are contemplated. In other embodiments, the retainer member  304 ′ can be a plurality of dog, key, pin, or slip members, positioned around the latch assembly  300 ′. In embodiments where the retainer member  304 ′ is a plurality of dog or key members, the dog or key members can optionally be spring-biased. Although a single retainer member  304 ′ is described herein, a plurality of retainer members  304 ′ can be used. The retainer member  304 ′ has a cross section sufficient to engage positively the latching formation  311 ′ to limit axial movement of the latch assembly  300 ′ and still engage with the latch assembly  300 ′. 
     Shoulder  208 ′ of the rotating control device  100 ′ in this embodiment lands on a landing formation  308 ′ of the latch assembly  300 ′, limiting downward or downhole movement of the rotating control device  100 ′ in the latch assembly  300 ′. As stated above, the latch assembly  300 ′ can be manufactured for use with a specific housing section, such as housing section  310 ′, designed to mate with the latch assembly  300 ′. In contrast, the latch assembly  210 ′ of  FIG. 11  can be manufactured to standard sizes and for use with various generic housing sections  200 ′, which need no modification for use with the latch assembly  210 ′. 
     Cables (not shown) can be connected to eyelets or rings  322 A′ and  322 B′ mounted on the rotating control device  100 ′ to allow positioning of the rotating control device  100 ′ before and after installation in a latch assembly. The use of cables and eyelets for positioning and removal of the rotating control device  100 ′ is exemplary and illustrative, and other positioning apparatus and numbers and arrangements of eyelets or other attachment apparatus, such as discussed below, can be used. 
     Similarly, the latch assembly  300 ′ can be positioned in the housing section  310 ′ using cables (not shown) connected to eyelets  306 A′ and  306 B′, mounted on an upper surface of the latch assembly  300 ′. Although only two such eyelets  306 A′ and  306 B′ are shown in  FIG. 12 , other numbers and placements of eyelets can be used. Additionally, other techniques for mounting cables and other techniques for positioning the unlatched latch assembly  300 ′, such as discussed below, can be used. As desired by the operator of a rig, the latch assembly  300 ′ can be positioned or removed in the housing section  310 ′ with or without the rotating control device  100 ′. Thus, should the rotating control device  100  fail to unlatch from the latch assembly  300 ′ when desired, for example, the latched rotating control device  100 ′ and latch assembly  300 ′ can be unlatched from the housing section  310 ′ and removed as a unit for repair or replacement. In other embodiments, a shoulder of a running tool, tool joint  260 A′ of a string  260 ′ of pipe, or any other shoulder on a tubular that could engage lower stripper rubber  246 ′ can be used for positioning the rotating control device  100  instead of the above-discussed eyelets and cables. An exemplary tool joint  260 A′ of a string of pipe  260 ′ is illustrated in phantom in  FIG. 11 . 
     As best shown in  FIG. 11 , the rotating control device  100  includes a bearing assembly  240 ′. The bearing assembly  240 ′ is similar to the Weatherford-Williams model 7875 rotating control device, now available from Weatherford International, Inc., of Houston, Tex. Alternatively. Weatherford-Williams models 7000, 7100, IP-1000, 7800, 8000/9000, and 9200 rotating control devices or the Weatherford RPM SYSTEM 3000™, now available from Weatherford International, Inc., could be used. Preferably, a rotating control device  240 ′ with two spaced-apart seals, such as stripper rubbers, is used to provide redundant sealing. The major components of the bearing assembly  240 ′ are described in U.S. Pat. No. 5,662,181, now owned by Weatherford/Lamb, Inc., which is incorporated herein by reference in its entirety for all purposes. Generally, the bearing assembly  240 ′ includes a top rubber pot  242 ′ that is sized to receive a top stripper rubber or inner member seal  244 ′; however, the top rubber pot  242 ′ and seal  244 ′ can be omitted, if desired. Preferably, a bottom stripper rubber or inner member seal  246 ′ is connected with the top seal  244 ′ by the inner member of the bearing assembly  240 ′. The outer member of the bearing assembly  240 ′ is rotatably connected with the inner member. In addition, the seals  244 ′ and  246 ′ can be passive stripper rubber seals, as illustrated, or active seals as known by those of ordinary skill in the art. 
     In the embodiment of a single hydraulic latch assembly  210 ′, such as illustrated in  FIG. 11 , a lower accumulator may be required because hoses and lines cannot be used to maintain hydraulic fluid pressure in the bearing assembly  100 ′ lower portion. In addition, an accumulator allows the bearings (not shown) to be self-lubricating. An additional accumulator can be provided in the upper portion of the bearing assembly  100 ′ if desired. 
     Turning to  FIG. 13 , RCD  1022  is latched with housing  1020 . While in operation, housing  1020  would be disposed subsea with a marine riser or directly with the wellhead or BOP stack if there were no riser. Housing  1020  has an internal latching assembly for latching the RCD  1022  or other oilfield device. First electro-hydraulic umbilical line  1024  is connected at one end with housing  1020  and may provide for the primary control for the latching assembly in housing  1020 . Second electro-hydraulic umbilical line  1026  is connected at one end with a valve pack (not shown) and may also provide control for the latching assembly in housing  1020 . Accumulators ( 1023 ,  1025 ) are removably attached to housing  1020  with accumulator clamp ring  1021 . There may be four accumulators, such as shown in  FIG. 21 . Other numbers of accumulators are also contemplated. Returning to  FIG. 13 , signal device  1031  is in a stowed position below accumulators ( 1023 ,  1025 ). The valve pack may switch between the fluid flowing through second electro-hydraulic umbilical line  1026  and the fluid flowing from accumulators ( 1023 ,  1025 ), as will be discussed in detail below. Umbilical reels ( 1028 ,  1030 ) store respective umbilical lines ( 1024 ,  1026 ). Although an RCD  1022  is shown, it is contemplated that any oilfield device may be latched with the housing  1020 , including, but not limited to, protective sleeves, bearing assemblies with no stripper rubbers, stripper rubbers, wireline devices, and any other oilfield devices for use with a wellbore. 
     In  FIG. 14 , acoustic control system  1007  may include surface control unit  1004 , subsea control unit  1010 , first acoustic signal device  1006  and second acoustic signal device  1008 . A third acoustic signal device  1008 A is also contemplated, as are additional acoustic signal devices. Second and third acoustic signal devices ( 1008 ,  1008 A), subsea control unit  1010 , and valve pack  1012  may be disposed directly with one or more operating accumulators  1016 , one or more receiving accumulators or compensators  1062 , on housing  1014 , but are shown in exploded view in  FIG. 14  for clarity. Housing  1014  contains an internal latching assembly to latch with an oilfield device, such as an RCD. 
     It is contemplated that the subsea components, including second and third acoustic signal devices ( 1008 ,  1008 A), subsea control unit  1010 , valve pack  1012 , operating accumulators  1016 , and receiving accumulator  1062 , may be housed on a frame structure or pod around housing  1014 . Second and third acoustic signal devices ( 1008 ,  1008 A) may be supported on pivoting arms or extensions from the frame structure, although other attachment means are also contemplated. First signal device  1006  may be held below the water surface by reel  1005 . First signal device  1006  may transmit acoustic signals as controlled by surface control unit  1004 , and second acoustic device  1008  may receive the acoustic signals and transmit them to subsea control unit  1012 . 
     First and second acoustic signal devices ( 1006 ,  1008 ) may be transceivers to provide for two-way communication so that both devices ( 1006 ,  1008 ) may transmit and receive communication signals from each other as controlled by their respective control units ( 1004 ,  1010 ). Devices ( 1006 ,  1008 ) may also be transceivers connected with transducers. Third signal device  1008 A may also be a transceiver or a transceiver coupled with a transducer. 
     Acoustic control systems may be available from Kongsberg Maritime AS of Horten, Norway; Sonardyne Inc. of Houston, Tex.; Nautronix of Aberdeen, Scotland; and/or Oceaneering International Inc. of Houston, Tex., among others. An acoustic actuator may be used in the acoustic control system, such as is available from ORE Offshore of West Wareham, Mass., among others. It is contemplated that acoustic control system  1007  may operate in depths of up to 200 feet (61 m). It is also contemplated that acoustic signal devices ( 1006 ,  1008 ,  1008 A) may be sonde devices. Other acoustic transmitting and receiving means as are known in the art are also contemplated. It is also contemplated that alternative optical and/or electromagnetic transmission techniques may be used. 
     Acoustic control system  1007  allows communication through acoustic signaling between the control unit  1004  above the surface of the water and the subsea control unit  1010 . Subsea control unit  1010  may be in electrical communication or connection with valve pack  1012 , which may be operable to activate one or more operating accumulators  1016  and release their stored hydraulic fluid. Operating accumulators  1016  may be pre-charged to 44 Barg, although other pressures are also contemplated. Unlike operating accumulators  1016 , one or more receiving accumulators or compensators  1062  may not store pressurized hydraulic fluid for operation of the latching assembly in RCD housing  1014 , but rather may receive hydraulic fluid exiting the latching assembly. 
     Valve pack  1012  may also be used to switch from a primary umbilical line system, such as second umbilical line  1026  in  FIG. 13 , to the secondary acoustic control system. It is also contemplated that the acoustic control system may be the primary system. Operating accumulators  1016  may be remotely or manually charged and/or purged, including by an ROV or diver. Although two operating accumulators  1016  are shown, it is contemplated that there may be only one operating accumulator  1016 , or more than two operating accumulators  1016 . 
     Operating accumulators  1016  and receiving accumulator  1064  are disposed with housing  1014 , which may be positioned with a marine riser or otherwise with the subsea wellbore, such as with a subsea housing. An RCD or other oilfield device (not shown in  FIG. 14 ) may be latched with the internal latching assembly in housing  1014 . The housing  1014  latching assembly (not shown) may be similar to those latching assemblies shown in  FIGS. 1 to 12 . Housing  1014  may be disposed on a marine riser below the tension lines or tension ring. Operating accumulators  1016  may provide storage of energized hydraulic fluid to operate the latching assembly upon signal from the acoustic control system  1007 . It is contemplated that bladder type accumulators may be used. Other types of accumulators are also contemplated, such as piston type. Operating accumulators  1016  may be rechargeable in their subsea position. 
     Using  FIG. 1  for illustrative purposes, after the acoustic control system and latching system of  FIG. 14  is disposed with the system of  FIG. 1 , operating accumulators  1016  may discharge their fluid into the latching assembly to move lower secondary piston  1000  and/or upper secondary piston  1002 , and urge their respective adjacent primary pistons ( 14 ,  18 ) upward so as to release their respective retaining members ( 16 ,  20 ) and unlatch the RCD  100  from the housing  12  or marine riser  10 . It is also contemplated that accumulators may be used to directly move the primary pistons ( 14 ,  18 ). It is also contemplated that the accumulators may be used to expand active seal  22 . 
     Returning to  FIG. 14 , housing  1014  with latching assembly may have a bottom flange that may be bolted to the marine riser, subsea housing, wellhead and/or BOP stack. The housing  1014  inside profile may contain a hydraulic latch that is fabricated to receive, retain, and release the RCD or other oilfield device with locking retainer members. The housing  1014  may have lifting eyes for convenience in positioning. 
     Turning to  FIG. 15 , an exemplary configuration is shown for a secondary latch operating system and a primary umbilical line system. The secondary system may be operated using the acoustic control system  1007  of  FIG. 14 . Other embodiments and configurations are also contemplated. Returning to  FIG. 15 , operating accumulators  1016  are shown in hydraulic fluid communication with valve pack  1012 . Operating accumulators  1016  may contain hydraulic fluid under pressure, such as pressurized by Nitrogen gas. Although two operating accumulators  1016  are shown, it is also contemplated that only one operating accumulator  1016  may be used. Operating accumulators  1016  may be periodically charged and/or purged. It is contemplated that a gauge may continuously monitor their pressure(s). The gauge and/or valves on the charge line may be used to charge and/or purge accumulators  1016 . 
     Valve pack  1012  may include first valve  1040 , second valve  1042  and third valve  1044 , each of which may be a two-position hydraulic valve. Other types of valves are also contemplated. Valves ( 1040 ,  1042 ,  1044 ) may be controlled by a hydraulic “pilot” line  1078  that is pressurized to move the valve. It is also contemplated that a processor or PLC could control the valves ( 1040 ,  1042 ,  1044 ) using an electrical line. Remote operation is also contemplated. The valve pack  1012  may contain electric over hydraulic valves, pilot operated control valves, and manual control valves. 
     The subsea control unit  1010  (as shown in  FIG. 14 ) may primarily direct the operation of the valve pack  1012  through commands sent to it from the surface control unit or console  1004 . The subsea control unit  1010  may be attached at the same location as a measurement device or sensor  1064 . Other locations for attachment are also contemplated. It is contemplated that measurement devices or sensors ( 1064 ,  1066 ,  1074 ,  1076 ) may measure temperature, pressure, flow, and/or other conditions. Sensors ( 1074 ,  1076 ) may be open to seawater. It is contemplated that sensors ( 1064 ,  1066 ) may measure hydraulic pressure and/or seawater pressure, sensor  1076  may measure seawater temperature, and sensor  1074  may measure seawater pressure. It is also contemplated that other temperatures and pressures may be measured, like well pressure. 
     An electro-hydraulic umbilical line, such as second electro-hydraulic line  1026  shown in  FIG. 13 , comprising three independent hydraulic lines may extend from the drilling rig or structure to the housing with a latching assembly and/or active seal. A first hydraulic line may be attached with first umbilical input port  1046  connected with first inner umbilical line  1046 A, a second hydraulic line may be attached with second umbilical input port  1048  connected with second inner umbilical line  1048 A, and a third hydraulic line may be attached with third umbilical input port  1050  connected with third inner umbilical line  1050 A. The housing with latching assembly may be attached with first input port  1052 , second input port  1054 , and third input port  1056 . First input port  1052  may be in fluid communication with the cavities or space above the primary piston(s) in the latching assembly, second input port  1054  may be in fluid communication with the cavities or space immediately below the primary piston(s) in the latching assembly, and third input port  1056  may be in fluid communication with the cavities or space below the secondary piston(s) in the latching assembly. Other configurations are also contemplated. 
     Using  FIG. 1  for illustrative purposes, for the primary latching assembly operation, when allowed by first valve  1040 , hydraulic fluid from umbilical line may move through first inner umbilical line  1046 A through first input port  1052  to the latching assembly for latching or closing the latches by moving the primary pistons ( 14 ,  18 ) downward to the positions shown in  FIG. 1 . When allowed by second valve  1042 , hydraulic fluid from umbilical line may move through second inner umbilical line  1048 A through second input port  1054  to the latching assembly for unlatching or opening the latches by moving the primary pistons ( 14 ,  18 ) upward from the positions shown in  FIG. 1 . When allowed by third valve  1044 , hydraulic fluid from umbilical line may move through third input port  1056  to the latching assembly for unlatching or opening the latches by moving the secondary pistons ( 1000 ,  1002 ) upward from the positions shown in  FIG. 1 . Operation of the secondary pistons ( 1000 ,  1002 ) is generally used for emergency situations when the primary pistons may not be moved. 
     When the umbilical line is damaged, and the secondary operating system may be required to remove a latched RCD or other oilfield device. A PLC may control valve pack  1012  to close the movement of hydraulic fluid from first, second and third inner umbilical lines ( 1046 A,  1048 A,  1050 A) and open first accumulator line  1080 , second accumulator line  1082 , and third accumulator line  1083 . As can now be understood, first, second and third valves ( 1040 ,  1042 ,  1044 ) of the valve pack  1012  may have a first and a second position. The first position may allow operation of the primary system, and the second position may allow operation of the secondary system using the acoustic control system  1007 . 
     Check valves ( 1068 ,  1070 ,  1072 ) in the hydraulic lines allow flow in the forward direction, and prevent flow in the reverse direction. However, it is contemplated that check valves ( 1068 ,  1070 ,  1072 ) may be pilot-to-open check valves that do allow flow in the reverse direction when needed by opening the poppet. Other types of check valves are also contemplated. It is also contemplated that there may be no check valve  1072  in second accumulator line  1082 . 
     When allowed by valve pack  1012 , operating accumulators  1016  may discharge their stored charged hydraulic fluid through third accumulator line  1083  to move the secondary piston(s), such as secondary pistons ( 1000 ,  1002 ) in  FIG. 1 . Hydraulic fluid from the latch assembly displaced by the movement of the secondary pistons may move through first accumulator line  1080  and/or check valve  1068  to receiving accumulator or compensator  1062 . Other paths are also contemplated. Receiving accumulator  1062 , unlike operating accumulators  1016 , may not contain pressurized hydraulic fluid. Rather, it may contain seawater, fresh water or other liquid and may be used to receive or catch the hydraulic fluid returns from the latching assembly to prevent their discharge into the environment or sea. It is also contemplated that, if desired, there could be no receiving accumulator  1062 . 
     It is contemplated that the acoustic control system  1007  may be used as a back-up to the primary system, which may be one or more umbilical lines. An electro-hydraulic umbilical reel may be used to store the primary line and supply electric and hydraulic power to the RCD housing. It is also contemplated that there may also be ROV and/or human diver access for system operation. It is contemplated that the system may operate in seawater depths up to 197 feet (60 m). It is contemplated that the system may operate in temperatures ranging from 32° F. (0° C.) to 104° F. (40° C.). It is contemplated that the system opening pressure may be 700 psi (48 bar) or greater when performing an unlatching operation. It is contemplated that the system opening pressure may not exceed 1200 psi (83 bar) when performing an unlatching operation. 
     It is contemplated that the system flow rate may not be more than 10 gpm (381 pm) or greater when performing an unlatching operation. It is contemplated that the system flow rate may be 0.75 gpm (2.81 bar) or greater to fully unlatch the primary and secondary latches. It is contemplated that system flow volume may be between 0.75 gallons (2.84 liters) and 1.35 gallons (5.11 liters) to unlatch (open) the primary and secondary latches at least once. The operating accumulators  1016  may be rechargeable in their subsea positions. It is contemplated that the system be operable with Weatherford Model 7878 BTR. As alternative embodiments, instead of operating accumulators  1016 , or in addition to them, a self contained power source, such as electrical, hydraulic, radio control, or other type, may be used so that when remotely signaled it would release stored energy to cause the primary and secondary unlock circuits of the latching assembly to function. 
     It is contemplated that fluid returns from the latching assembly when operating with the acoustic control system and latch operating system shown in  FIGS. 14 and 15  would not be ejected into the environment, but captured. It is contemplated that a monitoring gauge may be attached with the charge line of the operating accumulators  1016 , such as to monitor pressure. The gauge may be used to add or remove hydraulic fluid and to increase or decrease pressure. There may be valves about the accumulator charge line connection and gauge to permit manual charging or purging of the system. The system may be easily attached with the housing. 
       FIGS. 16 to 18  show some of the environments in which the acoustic control system  1007  and latch operating system of  FIGS. 13-15  may be used. Other environments are also contemplated. In  FIG. 16 , floating drilling rig or structure S is disposed over wellhead W. Subsea BOP stack BOPS is disposed on wellhead W, and marine riser R with gas handler annular BOP GH extends between the BOPS and rig S. Tension lines T are attached with the slip joint SJ near the top of the riser R with a tensioner ring (not shown). A diverter D is below the rig floor F. 
     Acoustic control system  1007  is positioned with structure S and riser R. An RCD or other oilfield device (not shown) may be latched within housing  1014  positioned with riser R below tension lines T and tension ring adjacent the location of the gas handler annular BOP GH. It is contemplated than a housing  1014  with latched RCD or other oilfield device may be disposed with a frame structure or pod supporting valve pack  1012 , accumulators ( 1016 ,  1062 ), subsea control unit  1010 , and subsea signal devices ( 1008 ,  1008 A). Surface equipment including surface control unit  1004 , reel  1005 , and signal device  1006  may be supported from the rig S. 
     In  FIG. 17 , RCD  38 A is disposed with a subsea housing SH at the sea floor SF and disposed with the subsea wellhead W. Subsea housing SH and RCD  38 A allow for subsea drilling with no marine riser. In  FIG. 18 . RCD  38 A is disposed with a subsea housing SH 1  disposed over subsea BOP stack BOPS. Subsea housing SH 1  and RCD  38 A allow for subsea drilling with no marine riser. The acoustic control system  1007  and latch operating system as shown in  FIGS. 13-16  may be disposed with the subsea housings (SH, SH 1 ) of  FIGS. 17 and 18  and used for operating a latch assembly for latching and unlatching the RCD  38 A and/or for expanding and decreasing an active seal. It is contemplated that the components of the system may be supported on a frame structure or pod. 
     Turning to  FIG. 19 , an RCD  1102  is latched with housing  1100 . Although an RCD  1102  is shown, it is contemplated that any oilfield device may be latched with the housing  1100 . While in operation, housing  1100  would be disposed subsea with a marine riser or directly with the wellhead or BOP stack if there were no riser. Housing  1100  has an internal latching assembly for latching the RCD  1102  or other oilfield device. Accumulators ( 1106 ,  1108 ) are removably attached to housing  1100  with accumulator clamp ring  1104 . There may be four accumulators, such as shown in  FIG. 21 . As discussed above, other numbers of accumulators are contemplated. Returning to  FIG. 19 , signal device  1110  is in a stowed position below accumulators ( 1106 ,  1108 ). Accumulators may store a fluid for operation of the internal latching assembly of the housing  1100 . In  FIG. 20 , signal device  1110  has been moved to a deployed position. 
     In  FIG. 21 , three operating accumulators ( 1106 ,  1108 ,  1112 ) are provided for releasing hydraulic fluid to the latching assembly, as discussed above, in housing  1100 . A receiving accumulator or compensator  1114  is for receiving hydraulic fluid from the latching assembly in housing  1100 . The accumulators ( 1106 ,  1108 ,  1112 ,  1114 ) are attached to housing  1100  using accumulator clamp ring  1104 . As shown in  FIG. 22 , the signal device ( 1110 ,  1110 A) is movable by pivoting from a stowed position (in phantom view) to a deployed position. 
     Turning to  FIGS. 23A-23B , an exemplary configuration is shown for a secondary latch operating system and a primary umbilical line system. The secondary system may be operated with acoustic control system  1007 . Other embodiments and configurations are also contemplated. Operating accumulators ( 1120 ,  1122 ,  1124 ) are shown in hydraulic fluid communication with manifold or valve pack  1128 . Operating accumulators ( 1120 ,  1122 ,  1124 ) may contain hydraulic fluid under pressure, such as pressurized by Nitrogen gas. Although three operating accumulators are shown in  FIGS. 21-23A , it is also contemplated that only one operating accumulator could be used. Operating accumulators may be periodically charged and/or purged. It is contemplated that a gauge may continuously monitor their pressure(s). The gauge and/or valves on the charge line may be used to charge and/or purge accumulators. Accumulator or compensator  1126  may be used to received hydraulic fluid as discussed above. 
     Manifold or valve pack  1128  may include first valve  1130 , second valve  1132  and third valve  1134 , each of which may be two-position hydraulic valves. Other types of valves are also contemplated. Valves ( 1130 ,  1132 ,  1134 ) may be controlled by a hydraulic “pilot” line  1136  that is pressurized to move the respective valve. As best shown in  FIG. 23B , the acoustic control system  1007  may use an electric over hydraulic control over valves ( 1130 ,  1132 ,  1134 ). The valves ( 1160 ,  1162 ,  1164 ) control the function of both switching from the primary umbilical line system to the secondary latch operating system and performing the emergency unlatch operation by the secondary latch operating system. Valves ( 1160 ,  1162 ) may be electrically controlled by subsea control units (SCU) ( 1136 ,  1138 ) as shown in  FIG. 23A . Valve  1164  is pilot-operated by valve  1162 . 
     In particular, activation of valve  1164  will pilot-operate and switch valves ( 1130 ,  1132 ,  1134 ) from the primary umbilical line system to the secondary latch operating system. This switching allows the emergency unlatching of the latching assembly where valve  1164  is activated by the pilot-operated control valve  1162 . Activation of valve  1164  allows pressurized hydraulic fluid from the accumulator(s) ( 1120 ,  1122 ,  1124 ) to unlatch the RCD or other oilfield device from the housing using the secondary latch operating system. The accumulators ( 1120 ,  1122 ,  1124 ) may be 10-liter subsea bladder accumulators with a seal subfluid connection, ¼″ BSPM gas connection, a C/W lifting eye bolt, SCHRADER valve and cushion ring. Compensator  1126  may be a 10-liter subsea compensator being internally nickel-plated ½″ BSP hydraulic fluid connection open seawater connection 207 BARG design pressure and C/W cushion ring. A valve  1166  may be a ⅜″ NB subsea manual needle valve C/W ½″ OD×0.65″ WT 38 mm long tube tail. Coupler  168  may be a ⅜″ NB male flange mounted mono coupler universal un-vented C/W 1000 mm tube tail ½″×0.065″ WT. Coupler  1170  may be a ⅜″ NB female mono coupler universal (un-vented) C/W JIC #8 CHEMRAS seals. Couplings  1172  may be a ¼″ NB female stabplate mounted hydraulic coupling universal C/W 17 mm seal-sub back end ¼″ UNC holes un-vented. Couplings  1174  may be ¼″ NB stabplate mounted male “reduced forge” hydraulic couplings universal #8 JIC un-vented. The valves  1130 ,  1132  and  1134  may be 2-position, 3-way normally open poppet valve. Valve  1164  may be a 2-position, 2-way normally closed poppet valve. Valves  1160  and  1162  may be 2-position, 3-way normally closed 24 volt DC solenoid valve C/W 3 m RAYCHEM Fyling leads. Sensor  1146  may be a ¼″ BSP manifold-mounted pressure transducer, 0-1000 BARG. Transducer  1144  could be a ¼″ BSP manifold-mounted temperature transducer (seawater temp). Ports  1154 ,  1156  and  1158  could include a ¼″ stabplate coupling male, 569 BARG ½″×0.065″ WT×1000 mm tube tail. It is also contemplated that a processor or PLC could control the valves ( 1130 ,  1132 ,  1134 ) using an electrical line. Remote operation is also contemplated. The valve pack  1128  may contain electric over hydraulic valves, pilot operated control valves, and/or manual control valves. 
     Subsea control units ( 1136 ,  1138 ) may primarily direct the operation of the valve pack  1128  through commands sent to the subsea control units from a surface control unit or console, such as unit  1004  shown in  FIGS. 14 and 16 . The subsea control units ( 1136 ,  1138 ) may be attached at the same location as measurement device or sensor  1140 . Other locations for attachment are also contemplated. Measurement devices or sensors ( 1140 ,  1142 ,  1144 ,  1146 ) may measure temperature, pressure, flow, and/or other conditions. Sensors ( 1144 ,  1146 ) may be open to seawater. It is contemplated that sensors ( 1140 ,  1142 ) may measure hydraulic pressure and/or seawater pressure, sensor  1146  may measure seawater temperature, and sensor  1144  may measure seawater pressure. It is also contemplated that other temperatures and pressures may be measured, like well pressure. 
     An electro-hydraulic umbilical line, such as second electro-hydraulic line  1026 , shown in  FIG. 13 , containing three independent hydraulic lines may extend from the drilling rig or structure to the housing with a latching assembly or active seal. Referring to both  FIGS. 23A and 23B , a first hydraulic line may be attached with first umbilical input port  1148  connected with first inner umbilical line  1148 A, a second hydraulic line may be attached with second umbilical input port  1150  connected with second inner umbilical line  1150 A, and a third hydraulic line may be attached with third umbilical input port  1152  connected with third inner umbilical line  1152 A. The housing with latching assembly may be attached with first input port  1154 , second input port  1156 , and third input port  1158 . First input port  1154  may be in fluid communication with the cavities or space above the primary pistons in the latching assembly, second input port  1156  may be in fluid communication with the cavities or space immediately below the primary pistons in the latching assembly, and third input port  1158  may be in fluid communication with the cavities or space below the secondary pistons in the latching assembly. Other configurations are also contemplated. 
     As can now be understood, the system may monitor seawater temperature and pressure and stored hydraulic supply and return pressure. The system also provides the ability to remotely control the open and close valves and provides enough stored volume in the accumulators to operate the emergency unlatching in the event of a primary and secondary latch hydraulic failure. The design of the control system may be based on two acoustic subsea control units (SCUs) mounted on the housing that will receive signals from the topside acoustic command unit and operate the directional control valves. The two acoustic subsea control units will also send signals, such as 4-20 mA signals, to the topside acoustic control unit. As best shown in  FIG. 23A , two acoustic subsea control units (SCUs) ( 1136 ,  1138 ) may be used but it should be understood that only one SCU may be used to implement the function of the acoustic control system  1007 . The design of the system may offer, among other things, (1) a redundant subsea system with two complete sets of electronics with separate replaceable batteries, (2) high availability and reliability based on equipment selection, design principles, (3) low electrical power consumption, and (4) low maintenance. 
     It is contemplated that the system may operate in seawater up to 197 feet (60 meters) below the surface. The system may operate in a temperature range from 32° F. (0° C.) to 104° F. (40° C.). The system opening pressure may be 700 psi (48 bar) or greater when performing an emergency unlatching (open) operation. The system opening pressure may not exceed 1200 psi (83 bar) when performing an emergency unlatching (open) operation. The system flow rate may not exceed 0.75 gpm (2.81 bar) when performing an emergency unlatching (open) operation. The system flow volume may be between 0.75 gallons (2.84 liters) and 1.35 gallons (5.11 liters) to fully unlatch (open) the primary and the secondary latch pistons. 
     The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and system, and the construction and the method of operation may be made without departing from the spirit of the invention.