AU2012202558B2 - Riser Rotating Control Device - Google Patents

Abstract

A latch assembly is connectable to a riser. A rotating control device can be positioned with the riser, sealing the rotating control device with the latch assembly and removably latching the rotating control device to the latch assembly and to the riser. The latch assembly can be remotely actuated. The latch assembly can provide an auxiliary safety mechanism to provide a backup actuation mechanism to unlatch the rotating control device from the latch assembly. The latch assembly can be bolted to the riser. Alternately, the latch assembly can be latched with the riser using a similar latching mechanism as used to latch the latch assembly to the rotating control device. A pressure transducer protector assembly can protect a transducer for monitoring wellbore pressure in the riser. A remote indicator panel can indicate the status of the latch assembly. RISER ROTATING CONTROL Thomas F. Bailey, et al Serial No. not yet assigned CM 055010.0051 -_ e

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: WEATHERFORD/LAMB, INC. Actual Inventors: Thomas F. BAILEY, and James W. CHAMBERS Address for Service: FRASER OLD & SOHN Patent Attorneys Level 6, 118 Alfred Street MILSONS POINT NSW 2061 Invention Title: Riser Rotating Control Device Details of Parent Application: 2005 234 651 Dated 17 November 2005 In the name of Weatherford/Lamb, Inc The following statement is a full description of this invention, including the best method of performing it known to us: 1 3067AP-D1 RISER ROTATING CONTROL DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention {0001] The present invention relates to the field of oilfield drilling equipment and in particular to an apparatus and method for remotely sealing and latching a rotating control device with a riser. 2. Description of the Related Art [00021 Conventional offshore drilling techniques focus upon a decades-old technique that was hydraulic pressure generated by a preselected fluid inside the wellbore to control pressures in a formation being drilled. However, a majority of known resources, gas hydrates excluded, are considered economically undrillable with conventional techniques. [00031 Pore pressure depletion, the need to drill in deeper water, and increasing drilling costs indicate that the amount of known resources considered economically undrillable will continue to increase. Newer techniques, such as underbalanced drilling and managed pressure drilling have been used to control pressure in the wellbore. However, these techniques present a need for pressure management devices such as rotating control devices and diverters. [00041 Rotating control devices have been used in conventional offshore drilling. A rotating control device is a drill-through device with a rotating seal that contacts and seals against the drillstring (drill pipe, casing, Kelly, etc.) for the purposes of controlling the pressure or fluid flow to the surface. However, rig operators typically bolt conventional rotating control devices to a riser below the rotary table of a drilling rig. Such a fixed connection has presented health, safety, and environmental (HSE) problems for drilling operators because retrieving the rotating control device has required unbolting the rotating control device from the riser, requiring personnel to go below the rotary table of the rig in the moon pool to disconnect the rotating control device. In addition to the HSE concerns, the retrieval procedure is complex and time consuming, decreasing operational efficiency of the rig. Furthermore, space in the 1 3067AP-D1 area above the riser typically limits the drilling rig operator's ability to install equipment on top of the riser. BRIEF SUMMARY OF THE INVENTION [0004A] According to a first aspect of the invention there is provided an apparatus, comprising: a latch assembly comprising: a retainer member movable between an unlatched position and a latched position; and a first piston movable between a first position and a second position, the first piston causing the retainer member to move to the latched position when the first piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the first piston is in the second position, wherein the latch assembly is remotely actuatable for moving the first piston to the latched position; and a measuring device coupled to the latch assembly, said measuring device used to indicate the position of the first piston. [0004B1 According to a second aspect of the invention there is provided an apparatus, comprising: a housing section; a rotating control device adapted for positioning with the housing section; and a latch assembly latchable to the rotating control device, sealable with the rotating control device, and adapted to connect to the housing section, comprising: a retainer member movable between an unlatched position and a latched position, the retainer member latched with the rotating control device in the latched position; and a piston, movable between a first position and a second position, the piston causing the retainer member to move to the latched position when the piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the piston is in the second position; a latch position indicator system coupled to the latch assembly, comprising: 2 3067AP-I a fluid line operatively coupled to communicate fluid to the latch assembly; a measuring device, coupled to the fluid line for measuring a fluid value; and a comparator, coupled to the measuring device, configured to compare the measured fluid value to a predetermined fluid value. [0004C] According to a third aspect of the invention there is provided an apparatus, comprising: a housing section; a rotating control device having a rotatable inner member and an outer member, and adapted to seal with the housing section; and a latch assembly latchable to the rotating control device, sealable with the rotating control device, and adapted to connect to the housing section, wherein the latch assembly is remotely and hydraulically actuatable to latch the rotating control device with the housing section, and a latch position indicator system remotely and hydraulically coupled to the latch assembly. [0004D] According to another aspect of the invention there is provided a method, comprising: providing a latch assembly comprising: a retainer member movable between an unlatched position and a latched position; and a first piston movable between a first position and a second position, the first piston causing the retainer member to move to the latched position when the first piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the first piston is in the second position; remotely actuating the latch assembly so as to move the first piston to the latched position; and indicating the position of the first piston using a measuring device coupled to the latch assembly. 3 3067AP-DI [00051 Preferably, a rotating control device can be stabbed into and removably latched to an upper section of the riser or a riser or bell nipple positioned on the riser (hereinafter both referred to as a "housing section"), sealing the rotating control device to the upper section of the housing section. A remotely actuatable latch assembly latches the rotating control device to the housing section. Remote actuation allows an operator to unlatch the rotating control device from the riser quickly, without sending personnel into the moon pool to disconnect the rotating control device. Similarly, the rotating control device can be remotely latched with a latch assembly latched to the housing section. The latch assembly can be remotely latched and unlatched with the housing section. [0006] In one preferred embodiment, a latch assembly is bolted or otherwise fixedly attached to the riser. The rotating control device then latches with the latch assembly and seals with the latch assembly. A piston in the latch assembly moves between a first and a second position, respectively compressing a retainer member, which can be a plurality of spaced-apart dog members, radially inwardly to latch with the rotating control device and allowing the retainer member to disengage from the rotating control device. In a further preferred embodiment, a second piston can urge the first piston to move to the second position, providing a backup unlatching mechanism. The rotating control device has a latching formation that engages with the retainer member to latch the rotating control device with the latch assembly. The rotating control device can have a shoulder that lands on a landing formation of the housing section to limit downhole movement of the rotating control device. [00071 In another preferred embodiment, the latch assembly itself is latchable to the housing section, using a similar piston mechanism as used to latch the rotating control device to the latch assembly. In this other preferred embodiment, a third piston, when moved to a first position, expands a second retainer member, which can be a plurality of spaced-apart dog members, radially outwardly, engaging a latching formation of the housing section, to latch the latch assembly to the housing section. The latch assembly can be remotely actuated. The housing section has a landing formation that engages a landing shoulder of the latch assembly, limiting downhole movement of the latch assembly. The latch assembly also has a landing formation 4 3067AP-DI that engages a landing shoulder of the rotating control device, to limit downhole movement of the rotating control device. [0008] In one preferred embodiment, while a tool joint can be used to remove the rotating control device from the latch assembly, eyelets on an upper surface of the rotating control device are provided for moving the rotating control device before installation and could be used for positioning the rotating control device with the latch assembly. In another preferred embodiment, eyelets on an upper surface of the latch assembly can be used to position the latch assembly with the housing section. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0009] A better understanding of the present invention can be obtained when the following detailed description of various preferred embodiments is considered, by way of example only, in conjunction with the following drawings, in which: Figure 1 is an elevational view of a rotating control device and a dual diverter housing positioned on a blowout preventer stack below a rotary table; Figure 2 is a cross-section view of one embodiment of the rotating control device and a single hydraulic latch assembly to better illustrate the rotating control device shown in elevational view in Figure 1; Figure 2A is a cross-section view of a portion of one embodiment of the hydraulic latch assembly of Figure 2 illustrating using a plurality of dog members as a retaining member; Figure 3 is a cross-section view of the rotating control device and a second embodiment of a single diverter housing and a dual hydraulic latch assembly; Figure 4 is an enlarged cross-section detail view of an upper end of the rotating control device of Figures 1, 2, and 3 with an accumulator; Figure 5 is an enlarged cross-section detail view of a lower end of the rotating control device of Figures 1, 2, and 3 with an accumulator; 5 3067AP-Di Figure 6 is an enlarged cross-section detail view of one side of the dual hydraulic latch assembly of Figure 3, with both the rotating control device and the housing section unlatched from the latch assembly; Figure 7 is an enlarged cross-section detail view similar to Figure 6 with the dual hydraulic Latch assembly shown in the latched position with both the rotating control device and the housing section; Figure 8 is an enlarged cross-section detail view similar to Figure 6 with the dual hydraulic latch assembly shown in the unlatched position from both the rotating control device and the housing section and an auxiliary piston in an unlatched position; Figure 9 is a enlarged cross-section detail view of a transducer protector assembly in a housing section; and Figures IOA and lOB are enlarged cross-section views of two configurations of the transducer protector assembly in a housing section in relation to the dual hydraulic latch assembly of Figures 6-8.; Figures 1 IA-1 1H are enlarged cross-section detail views of the dual hydraulic latch assembly of Figures 6-8 taken along lines A-A, A-B, A-C, A-D, A-E, A-F, A G, and A-H of Figure 12, illustrating passageways of a hydraulic fluid pressure sensing system for communicating whether the dual latch assembly is unlatched or latched; Figure 12 is an end view of the dual hydraulic latch assembly of Figures 6-8 illustrating hydraulic connection ports corresponding to the cross-section views of Figures 1IA-l 1H; Figure 13 is a schematic view of a latch position indicator system for the dual hydraulic latch assembly of Figures 6-8; Figure 14 is a front view of an indicator panel for use with the latch position indicator system of Figure 13; 6 3067AP-D I Figures 15K-150 are enlarged cross-section views of the dual hydraulic latch assembly of Figures 6-8 taken along lines K-K, K-L, K-M, K-N, and K-O of Figure 16, illustrating passageways of a hydraulic fluid volume-sensing system for communicating whether the dual latch assembly is unlatched or latched; Figure 16 is an end view of the dual hydraulic latch assembly of Figures 6-8 illustrating hydraulic connection ports corresponding to the cross-section views of Figures 15K-150; Figure 17 is an enlarged cross-section detail view illustrating an electrical indicator system for transmitting whether the dual hydraulic latch assembly is unlatched or latched to the indicator panel of Figure 14; and Figure 18 is a diagram illustrating exemplary conditions for activating an alarm or a hom of the indicator panel of Figure 14 for safety purposes. DETAILED DESCRIPTION OF THE INVENTION 10010] Although the following is described in terms of a fixed offshore platform environment, other preferred embodiments are contemplated for onshore use. Additionally, although the following is described in terms of oilfield drilling, the disclosed preferred embodiments can be used in other operating environments and for drilling for non-petroleum fluids. 10011] Turning to Figure 1, a rotating control device 100 is shown latched into a riser or bell nipple 110 above a typical blowout preventer (BOP) stack, generally indicated at 120. As illustrated in Figure 1, the exemplary BOP stack 120 contains an annular BOP 121 and four ram-type BOPs 122A-122D. Other BOP stack 120 configurations are contemplated and the configuration of these BOP stacks is determined by the work being performed. The rotating control device 100 is shown below the rotary table 130 in a moon pool of a fixed offshore drilling rig, such as a jackup or platform rig. The remainder of the drilling rig is not shown for clarity of the figure and is not significant to this application. Two diverter conduits 115 and 117 extend from the riser nipple 110. The diverter conduits 115 and 117 are typically rigid conduits; however, flexible conduits or lines are contemplated. With the rotating control device 100 latched with the riser nipple 110, the combination of the rotating 7 3067AP-DI control device 100 and riser nipple 110 functions as a rotatable marine diverter. In this configuration, the operator can rotate drill pipe (not shown) while the rotating marine diverter is closed or connected to a choke, for managed pressure or underbalanced drilling. The present invention could be used with the closed-loop circulating systems as disclosed in U.S. Patent Application Publication No. 2003/0079912 Al published May 1, 2003 entitled "Drilling System and Method", International Publication No. 02/50398 Al published June 27, 2002 entitled "Closed Loop Fluid-Handling System for Well Drilling", and International Publication No. WO 03/071091 Al published August 28, 2003 entitled "Dynamic Annular Pressure Control Apparatus and Method." The disclosures of U.S. Patent Application Publication No. 2003/0079912 Al, International Publication No. WO 02/50398 Al and International Publication No. WO 03/071091 Al are incorporated herein in their entirety for all purposes. 100121 Figure 2 is a cross-section view of a preferred 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 of Figure 1. As shown in Figure 2, a latch assembly separately indicated at 210 is bolted to a housing section 200 with bolts 212A and 212B. Although only two bolts 212A and 212B are shown in Figure 2, 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 Figure 2, 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, as shown, for example, in the dual diverter preferred embodiment of Figure 1 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. 8 3067AP-D1 [0013] 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. [0014] Figure 2 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 preferred embodiments, the retainer member 218 can be a "C-shaped" retainer ring 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 preferred 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, as illustrated by dog members 250A, 250B, 250C, 250D, 250E, 250F, 250G, 250H, and 250I in Figure 2A. In preferred embodiments where the retainer member 218 is a plurality of dog or key members, the dog or key members can optionally be spring biased. The number, shape, and arrangement of dog members 250 illustrated in Figure 2A is illustrative and exemplary only, and other numbers, arrangements, and shapes can be used. 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. [00151 An annular piston 220 is shown in a first position in Figure 2, 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 Figure 2. Although shown in 3067AP-DI Figure 2 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. [00161 As best shown in the dual hydraulic latch assembly preferred embodiment of Figure 6, 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 (Figure 2) or 320 (Figure 6) 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, [0017] Returning now to Figure 2, 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, [00181 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. [00191 The hydraulic ports 230, 232 and 234 and their corresponding passageways shown in Figure 2 are exemplary and illustrative only, and other numbers and arrangements of hydraulic ports and passageways can be used. In 10 3067AP-DI 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. [0020] Thus, the rotating control device 100 illustrated in Figure 2 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. [0021] An assortment of seals is used between the various elements described herein, such as wiper seals and 0-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. [0022] For example, seals 224A and 224B seal the rotating control device 100 to the latch assembly 210. Although two seals 224A and 224B are shown in Figure 2, any number and arrangement of seals can be used. In one preferred embodiment, seals 224A and 224B are Parker Polypak* M-inch cross section seals from Parker Hannifin Corporation. Other seal types can be used to provide the desired sealing. [0023] Figure 3 illustrates a second preferred embodiment of a latch assembly, generally indicated at 300, that is a dual hydraulic latch assembly As with the single latch assembly 210 preferred embodiment illustrated in Figure 2, 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 Figure 3. 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 preferred embodiment of Figure 2 as a first latch subassembly. The various preferred embodiments of the dual hydraulic latch assembly discussed below as they relate to 11 3067AP-DI the first latch subassembly can be equally applied to the single hydraulic latch assembly of Figure 2. [0024] In addition to the first latch subassembly comprising the pistons 220 and 222 and the retainer member 218, the dual hydraulic latch assembly 300 preferred embodiment illustrated in Figure 3 provides a second latch subassembly comprising a third piston 302 and a second retainer member 304, In this preferred 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 preferred 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 preferred embodiment of the rotating control device 100 can be used with multiple dual hydraulic latch assembly preferred embodiments; alternately, different preferred embodiments of the rotating control device 100 can be used with each preferred embodiment of the dual hydraulic latch assembly 300 and housing section 310. [00251 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 Figure 3 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. [00261 In some preferred embodiments, the retainer member 304 can be a "C shaped" retainer ring 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 preferred embodiments, the retainer member 304 can be a plurality of dog, key, pin, or slip members,, positioned around the latch assembly 300. In preferred 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 12 3067AP-Dt 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. [0027] Shoulder 208 of the rotating control device 100 in this preferred 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 Figure 2 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. 100281 Cables (not shown) can be connected to eyelets or rings 322A and 322B 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. [0029] Similarly, the latch assembly 300 can be positioned in the housing section 310 using cables (not shown) connected to eyelets 306A and 306B, mounted on an upper surface of the latch assembly 300. Although only two such eyelets 306A and 306B are shown in Figure 3, 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 preferred embodiments, a shoulder of a running tool, tool joint 260A of a string 260 of pipe, or any other shoulder on a tubular that 13 3067AP-DI 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 260A of a string of pipe 260 is illustrated in phantom in Figure 2. [00301 As best shown in Figures 2, 4, and 5, 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, Texas. Alternatively, Weatherford Williams models 7000, 7100, IP-1000, 7800, 8000/9000, and 9200 rotating control devices or the Weatherford RPM SYSTEM 3000TM, 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. Patent 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 cr 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. [00311 In the preferred embodiment of a single hydraulic latch assembly 210, such as illustrated in Figure 2, the lower accumulator 510 as shown in Figure 5 is required, because hoses and lines cannot be used to maintain hydraulic fluid pressure in the bearing assembly 100 lower portion. In addition, the accumulator 510 allows the bearings (not shown) to be self-lubricating. An additional accumulator 410, as shown in Figure 4, can be provided in the upper portion of the bearing assembly 100 if desired. 100321 Turning to Figure 6, an enlarged cross-section view illustrates one side of the latch assembly 300. Both the first retainer member 218 and the second retainer member 304 are shown in their unlatched position, with pistons 220 and 302 in their 14 3067AP-D2 respective second, or unlatched, position. Sections 640 and 650 form an outer housing for the latch assembly 300, while sections 620 and 630 form an inner housing, illustrated in Figure 6 as threadedly connected to the outer housing 640 and 650. Other types of connections can be used to connect the inner housing and outer housing of the latch assembly 300. Furthermore, the number, shape, relative sizes, and structural interrelationships of the sections 620, 630, 640 and 650 are exemplary and illustrative only and other relative sizes, numbers, shapes, and configurations of sections, and arrangements of sections can be used to form inner and outer housings for the latch assembly 300. The inner housings 620 and 630 and the outer housings 640 and 650 form chambers 600 and 610, respectively. Pistons 220 and 222 are slidably positioned in chamber 600 and piston 302 is slidably positioned in chamber 610. The relative size and position of chambers 600 and 610 are exemplary and illustrative only. In particular, some preferred embodiments of the latch assembly 300 can have the relative position of chambers 610 and 600 reversed, with the first latch subassembly of pistons 220, 222, and retainer member 218 being lower (relative to Figure 6) than the second latch subassembly of piston 302 and retainer member 304, [0033] As illustrated in Figure 6, the piston 220 is axially aligned in an offset manner from the retainer member 218 by an amount sufficient to engage a tapered surface 604 on the outer periphery of the retainer member 218 with a corresponding tapered surface 602 on the inner periphery of the piston 220. The force exerted between the tapered surfaces 602 and 604 compresses the retainer member 218 radially inwardly to engage the groove 320. Similarly, the piston 302 is axially aligned in an offset manner from the retainer member 304 by an amount sufficient to engage a tapered surface 614 on the inner periphery of the retainer member 304 with a corresponding tapered surface 612 on the outer periphery of the piston 302. The force exerted between the tapered surfaces 612 and 614 expands the retainer member 304 radially outwardly to engage the groove 311. [0034] Although no piston is shown for urging piston 302 similar to the second or auxiliary piston 222 used to disengage the rotating control device from the latch assembly 300, it is contemplated that an auxiliary piston (not shown) to urge piston 302 from the first, latched position to the second, unlatched position could be used, if desired. 15 3067AP-DI [00351 Figures 6 to 8 illustrate the latch assembly 300 in three different positions. In Figure 6, both the retainer members 218 and 304 are in their retracted or unlatched position. Hydraulic fluid pressure in passageways 660 and 670 (the port for passageway 670 is not shown) move pistons 220 and 302 upward relative to the figure, allowing retainer member 218 to move radially outwardly and retainer member 304 to move radially inwardly to unlatch the rotating control device 100 from the latch assembly 300 and the latch assembly 300 from the housing section 310. No direct manipulation is required to move the retainer members 218 and 304 to their unlatched position. 10036] In Figures 6 to 8, the passageways 660, 670, 710, 720, and 810 that traverse the latch assembly 300 and the housing section 310 connect to ports on the side of the housing section 310. However, other positions for the connection ports can be used, such as on the top surface of the riser nipple as shown in Figure 2, with corresponding redirection of the passageways 660, 670, 710, 720, and 810 without traversing the housing section 310. Therefore, the position of the hydraulic ports and corresponding passageways shown in Figures 6 to 8 are illustrative and exemplary only, and other hydraulic ports and passageways and location of ports and passageways can be used. In particular, although Figures 6 to 8 show the passageways 660, 670, 710, 720, and 810 traversing the latch assembly 300 and housing section 310, the passageways can be contained solely within the latch assembly 300. [0037] Figure 7 shows both retainer members 218 and 304 in their latched position. Hydraulic pressure in passageway 710 (port not shown) and 720 move pistons 220 and 302 to their latched position, urging retainer members 218 and 304 to their respective latched positions. [0038] Figure 8 shows use of the auxiliary or secondary piston 222 to urge or move the piston 220 to its second, unlatched position, allowing radially outward expansion of retainer member 218 to unlatch the rotating control device 100 from the latch assembly 300. Hydraulic passageway 810 provides fluid pressure to actuate the piston 222. 16 3067AP-DI [00391 Furthermore, although Figures 6 to 8 illustrate the retainer member 218 and the retainer member 304 with both retainer members 218 and 304 being latched or both retainer members 218 and 304 being unlatched, operation of the latch assembly 300 can allow retainer member 218 to be in a latched position while retainer member 304 is in an unlatched position and vice versa. This variety of positioning is achieved since each of the hydraulic passageways 660,670, 710, 720, and 810 can be selectively and separately pressurized. [0040] Turning to Figure 9, a pressure transducer protector assembly, generally indicated at 900, attached to a sidewall of the housing section 310 protects a pressure transducer 950. A passage 905 extends through the sidewall of the housing section 310 between a wellbore W or an inward surface of the housing section 310 to an external surface 31OA of the housing section 310. A housing for the pressure transducer protector assembly 900 comprises sections 902 and 904 in the exemplary preferred embodiment illustrated in Figure 9. Section 904 extends through the passage 905 of the housing section 310 to the wellbore W, positioning a conventional diaphragm 910 at the wellbore end of section 904. A bore or chamber 920 formed interior to section 904 provides fluid communication from the diaphragm 910 to a pressure transducer 950 mounted in chamber 930 of section 902. Sections 902 and 904 are shown bolted to each other and to the housing section 310, to form the pressure transducer protector assembly 900. Other ways of connecting sections 902 and 904 to each other and to the housing section 310 or other housing section can be used. Additionally, the pressure transducer protector assembly 900 can be unitary, instead of comprising the two sections 902 and 904. Other shapes, arrangements, and configurations of sections 902 and 904 can be used. 10041] Pressure transducer 950 is a conventional pressure transducer and can be of any suitable type or manufacture. In one preferred embodiment, the pressure transducer 950 is a sealed guage pressure transducer. Additionally, other instrumentation can be inserted into the passage 905 for monitoring predetermined characteristics of the wellbore W. 10042] A plug 940 allows electrical connection to the transducer 950 for monitoring the pressure transducer 950. Electrical connections between the 17 3067AP-D] transducer 950 and plug 940 and between the plug 940 to an external monitor are not shown for clarity of the figure. [0043] Figures 1OA and 1OB illustrate two alternate preferred embodiments of the pressure transducer protector assembly 900 and illustrate an exemplary placement of the pressure transducer protector assembly 900 in the housing section 310. The placement of the pressure transducer protector assembly 900 in Figures 1 OA and 1 OB is exemplary and illustrative only, and the assembly 900 can be placed in any suitable location of the housing section 310. The assembly 900A of Figure 1 OA differs from the assembly 900B of Figure 1 OB only in the length of the section 904 and position of the diaphragm 910. In Figure I0A, the section 904A extends all the way through the housing section 310, placing the diaphragm 910 at the interior or wellbore W surface of the housing section 310. The alternate preferred embodiment of Figure 1OB instead limits the length of section 904B, placing the diaphragm 910 at the exterior end of a bore 1000 formed in the housing section 310. The alternate preferred embodiments of Figures 10A and lOB are exemplary cnly and other section 904 lengths and diaphragm 910 placements can be used, including one in which diaphragm 910 is positioned interior to the housing section 310 at the end of a passage similar to passage 1000 extending part way through the housing section 310. The preferred embodiment of Figure IOA is preferable, to avoid potential problems with mud or other substances clogging the diaphragm 910. The wellbore pressure measured by pressure transducer 950 can be used to protect against unlatching the selected latching assembly 300 if the wellbore pressure is above a predetermined amount. One value contemplated for the predetermined wellbore pressure is a range of above 20-30 PSI. Although illustrated with the dual hydraulic latch assembly 300 in Figures 1OA and I OB, the pressure transducer protector assembly 900 can be used with the single hydraulic latch assembly 210 of Figure 2. [0044] Figures 11 A-17 illustrate various alternate preferred embodiments for a latch position indicator system that can allow a system or rig operator to determine remotely whether the dual hydraulic latch assembly 300 is latched or unlatched to the housing section, such as housing section 310, and the rotating control device 100. Although Figures 1 A-17 are configured for the dual hydraulic latch assembly 300, one skilled in the art would recognize that the relevant portions of the latch position 18 3067AP-D indicator system can also be used with the single hydraulic latch assembly 210 of Figure 2, using only those elements related to latching the latch assembly to the rotating control device 100. [0045] In one preferred embodiment, illustrated in Figures 1 A-I H and Figure 12, hydraulic lines (not shown) provide fluid to the latch assembly 300 for determining whether the latch assembly 300 is latched or unlatched from the rotating control device 100 and the housing section 310. Hydraulic lines also provide fluid to the latch assembly 300 to move the pistons 220, 222, and 302. In the illustrated preferred embodiment, hydraulic fluid is provided from a fluid source (not shown) through a hydraulic line (not shown) to ports, best shown in Figure 12. Passageways internal to the housing section 310 and latch assembly 300 communicate the fluid to the pistons 220, 222, and 302 for moving the pistons 220, 222, and 302 between their unlatched and latched positions. In addition, passageways internal to the housing section 310 and latch assembly 300 communicate the fluid to the pistons 220, 222, and 302 for the latch position indicator system. Channels are formed in a surface of the pistons 220 and 302. As illustrated in Figures 1lA-11H, these channels in an operating orientation are substantially horizontal grooves that traverse a surface of the pistons 220 and 302. If piston 220 or 302 is in the latched position, the channel aligns with at least two of the passageways, allowing a return passageway for the hydraulic fluid. As described below in more detail with respect to Figure 13, a hydraulic fluid pressure in the return line can be used to indicate whether the piston 220 or 302 is in the latched or unlatched position. If the piston 220 or 302 is in the latched position, a hydraulic fluid pressure will indicate that the channel is providing fluid communication between the input hydraulic line and the return hydraulic line. If the piston 220 or 302 is in the unlatched position, the channel is not aligned with the passageways, producing a lower pressure on the return line. As described below in more detail, the pressure measurement could also be on the input line, with a higher pressure indicating non-alignment of the channel and passageways, hence the piston 220 or 302 is in the unlatched position, and a lower pressure indicating alignment of the channel and passageways, hence the piston 220 or 302 is in the latched position. As described below in more detail, a remote latch position indicator system can use these pressure values to cause indicators to display whether the pistons 220 and 302 are latched or unlatched. 19 3067AP-D1 [00461 Typically, the passageways are holes formed by drilling the applicable element, sometimes known as "gun-drilled holes." More than one drilling can be used for passageways that are not a single straight passageway, but that make turns within one or more element. However, other techniques for forming the passageways can be used. The positions, orientations, and relative sizes of the passageways illustrated in Figures 11 A- 11H are exemplary and illustrative only and other position, orientations, and relative sizes can be used. [00471 The channels of Figure 11 A-1 I H are illustrated as grooves, but any shape or configuration of channel can be used as desired, The positions, shape, orientations, and relative sizes of the channels illustrated in Figures 11 A- 11H are exemplary and illustrative only and other position, orientations, and relative sizes can be used. 100481 Turning to Figure 1 IA, which illustrates a slice of the latch assembly 300 and housing section 310 along line A-A, passageway 1101 formed in housing section 310 provides fluid communication from a hydraulic line (not shown) to the latch assembly 300 to provide hydraulic fluid to move piston 220 from the unlatched position to the latched position. A passageway 1103 formed in outer housing element 640 communications passageway 1101 and the chamber 600, allowing fluid to enter the chamber 600 and move piston 220 to the latched position. Passageway 1103 may actually be multiple passageways in multiple radial slices of latch assembly 300, as illustrated in Figures 11A, 11D, 11E, 11 F, and 11H, allowing fluid communication between passageway 1101 and chamber 600 in various rotational orientations of latch assembly 300 relative to housing section 310. In some preferred embodiments, corresponding channels (not labeled) in the housing section 310 can be used to provide fluid communication between the multiple passageways 1103. [0049] Also shown in Figure 11 A, passageway 1104 is formed in outer housing element 640, which communicates with a channel 1102 formed on a surface of piston 220 when piston 220 is in the latched position. Although, as shown in Figure 11 A, the passageway 1104 does not directly communicate with a hydraulic line input or return passageway in the housing section 310, a plurality of passageways 1104 in the various slices of Figures l lA-1I H are in fluid communication with each other via the channel 1102 when the piston 220 is in the latched position. 20 ? 3067AP-D1 [00501 Another plurality of passageways 1105 formed in outer housing element 640 provides fluid communication to chamber 600 between piston 220 and piston 222. Fluid pressure in chamber 600 through passageway 1105 urges piston 220 into the unlatched position, and moves piston 222 away from piston 220. Yet another plurality of passageways 1107 formed in outer housing element 640 provides fluid communication to chamber 600 such that fluid pressure urges piston 222 towards piston 220, and can, once piston 222 contacts piston 220, cause piston 220 to move into the unlatched position as an auxiliary or backup way of unlatching the latch assembly 300 from the rotating control device 100, should fluid pressure via passageway 1105 fail to move piston 220. Although as illustrated in Figure 11A, pistons 220 and 222 are in contact with each other when piston 220 is in the latched position, pistons 220 and 222 can be separated by a gap between them when the piston 220 is in the latched position, depending on the size and shape of the pistons 220 and 222 and the chamber 600. [00511 In addition, a passageway 1100 is formed in outer housing element 640. This passageway forms a portion of passageway 1112 described below with respect to Figure 11C. [0052] Turning now to Figure 11 B, piston 220 is shown in the latched position, as in Figure 1 IA, causing the passageway 1104 to be in fluid communication with the channel 1102 in piston 220. As illustrated in Figure 11B, passageway 1104 is further in fluid communication with passageway 1106 formed in housing section 310, which can be connected with a hydraulic line for supply or return of fluid to the latch assembly 300. If passageway 1106 is connected to a supply line, then hydraulic fluid input through passageway 1106 traverses passageway 1104 and channel 1102, then returns via passageways 1108 and 1110 to a return hydraulic line, as shown in Figure 11C. If passageway 1106 is connected to a return line, then hydraulic fluid input through passageways 1108 and 1110 traverses the channel 1102 to return via passageways 1104 and 1106 to the return line. Because fluid communication between passageways 1106 and 1108 is interrupted when piston 220 moves to the unlatched position, as shown in Figure 11 C, pressure in the line (supply or return) connected to passageway 1106 can indicate the position of piston 220. For example, if passageway 1106 is connected to a supply hydraulic line, a measured pressure value in the supply 21 3067AP-D1 line above a predetermined pressure value will indicate that the piston 220 is in the unlatched position. Alternately, if passageway 1106 is connected to a return hydraulic line, a measured pressure value in the return line below a predetermined pressure value will indicate that the piston 220 is in the unlatched position. [0053] Figure 1 IC illustrates a passageway 1108 in housing section 310 that is in fluid communication with passageway 1110 in outer housing element 640 of the latch assembly 300. As described above, when piston 220 is in the latched position, passageways 1108 and 1106 are in fluid communication with each other, via passageways 1104 and 1110, together with channel 1102 and are not in fluid communication when piston 220 is in the unlatched position. In addition, passageway 1108 is in fluid communication with passageway 1112. Turning to both Figure 11 C and Figure 1 IF, when piston 302 is in the latched position, as shown in Figure 11 F, passageway 1112 is in fluid communication with passageways 1116 and 1118 via channel 1114 formed in piston 302. Thus, when piston 302 is in the latched position, hydraulic fluid supplied by a hydraulic supply line connected to one of passageways 1108 and 1118 flows through the housing section 310 and latch assembly 300 to a hydraulic return line connected to the other of passageways 1108 and 1118. As with the passageways for indicating the position of piston 220, such fluid communication between passageways 1108 and 1118 can indicate that piston 302 is in the latched position, and lack of fluid communication between passageways 1108 and 1118 can indicate that piston 302 is in the unlatched position. For example, if passageway 1108 is connected to a hydraulic supply line, then if the measured pressure value in the supply line exceeds a predetermined pressure value, piston 302 is in the unlatched position, and if the measured pressure value in the supply line is below a predetermined pressure value, piston 302 is in the unlatched position. Alternately, if passageway 1108 is connected to a hydraulic return line, if the measured pressure value in the return line is equal to or above a predetermined pressure value, then piston 302 is in the latched position, and if the pressure in the return line is equal to or less than a predetermined pressure value, then piston 302 is in the unlatched position. [00541 Turning now to Figure I1D, passageway 1109 in the housing section 310 can provide hydraulic fluid through passageway 1105 in the- latch assembly 300 to chamber 600, urging piston 220 from the latched position to the unlatched position, as 22 3067AP-D1 -well as to move piston 222 away from piston 220. Similarly, in Figure 11E, passageway 1111 in the housing section 310 can provide hydraulic fluid through passageway 1107 in the latch assembly 300, urging piston 222, providing a backup technique for moving piston 220 from the latched position into the unlatched position, once piston 222 contacts piston 220. Likewise, as illustrated in Figure 11G, hydraulic fluid in passageway 1117 in the housing section 310 traverses passageway 1119 to enter chamber 610, moving piston 302 from the unlatched position to the latched position, while hydraulic fluid in passageway 1121 in the housing section 310, illustrated in Figure 1 1H, traverses passageway 1123 to enter chamber 610, moving piston 302 from the latched position to the unlatched position. [0055] Although described above in each case as entering chamber 600 or 610 from the corresponding passageways, one skilled in the art will recognize that fluid can also exit from the chambers when the piston is moved, depending on the direction of the move. For example, viewing Figure 11 A and Figure 11 D, pumping fluid through passageways 1101 and 1103 into chamber 600 can cause fluid to exit chamber 600 via passageways 1105 and I109, while pumping fluid through passageways 1109 and 1105 into chamber 600 can cause fluid to return from chamber 600 via passageways 1103 and 1101, as the piston 220 moves within chamber 600. [0056] Turning now to Figure 12, port 1210 is connected to passageway 1101, port 1220 is connected to passageway 1106, port 1230 is connected to passageway 1108, port 1240 is connected to passageway 1109, port 1250 is connected to passageway I11, port 1260 is connected to passageway 1118, port 1270 is connected to passageway 1117, and port 1280 is connected to passageway 1121. The arrangement of ports and order of the slices illustrated in Figures 11 A-11 H is exemplary and illustrative only, and other orders and arrangements of ports can be used. In addition, the placement of ports 1210 to 1280 illustrated in end view in Figure 12 is exemplary only, and other locations for the ports 1210 to 1280 can be used, such as discussed above on the side of the housing section 310, as desired. [0057] In addition to the ports 1210 to 1280, Figure 12 illustrates eyelets that can be used to connect cables or other equipment to the housing section 310 and latch assembly 300 for positioning the housing section 310 and latch assembly 300. 23 3067AP-DI Because the housing section 310 and latch assembly 300 can be latched and unlatched from each other and to the rotating control device 100 remotely using hydraulic line connected to ports 1210, 1240, 1250, 1270, and 1280, the housing section 310, the latch assembly 300 and the rotating control device 100 can be latched to or unlatched from each other and repositioned as desired without sending personnel below the rotary table 130. Likewise, because ports 1220, 1230, and 1260 can provide supply and return lines to a remote latch position indicator system, an operator of the rig does not need to send personnel below the rotary table 130 to determine the position of the latch assembly 300, but can do so remotely. 10058] Turning now to Figure 13, a schematic diagram for an alternate preferred embodiment of a system S for controlling the latch assembly 300 of Figures 6 to 8, including a latch position indicator system for remotely indicating the position of the latch assembly 300. The elements of Figure 13 represent functional characteristics of the system S rather than actual physical implementation, as is conventional with such schematics. [0059] Block 1400 represents a remote control display for the latch position indicator subsystem of the system S, and is further described in one preferred embodiment in Figure 14. Control lines 1310 connect pressure transducers (PT) 1340, 1342, 1344, 1346, and 1348 and flow meters (FM) 1350, 1352, 1354, 1356, 1358, and 1360. The flow meters FM can be totalizing flow meters. Typically, a programmable logic controller (PLC) or other similar measurement and control device, either at each pressure transducer PT and flow meter FM or remotely in the block 1400 reads an electrical output from the pressure transducer PT or flow meter FM and converts the output into a signal for use by the remote control display 1400, possibly by comparing a flow value or pressure value measured by the flow meter FM or pressure transducer PT to a predetermined flow value or pressure value, controlling the state of an indicator in the display 1400 according to a relative relationship between the measured value and the predetermined value. For example, if the measured flow value is less than a predetermined value, the display 1400 may indicate one state of the flow meter FM or corresponding device, and if the measured flow value is greater than a predetermined value, the display 1400 may indicate another state of the flow meter FM or corresponding device. 24 3067AP-D] [00601 A fluid supply subsystem 1330 provides a controlled hydraulic fluid pressure to a fluid valve subsystem 1320. As illustrated in Figure 13, the fluid supply subsystem 1330 includes shutoff valves 1331A and 1331B, reservoirs 1332A and 1332B, an accumulator 1333, a fluid filter 1334, a pump 1335, pressure relief valves 1336 and 1337, a gauge 1338, and a check valve 1339, connected as illustrated. However, the fluid supply subsystem 1330 illustrated in Figure 13 can be any convenient fluid supply subsystem for supplying hydraulic fluid at a controlled pressure. [00611 A fluid valve subsystem 1320 controls the provision of fluid to hydraulic fluid lines (unnumbered) that connect to the cylinders 1370, 1380 and 1390. Figure 13 illustrates the subsystem 1320 using three directional valves 1324, 1325 and 1326, each connected to one of reservoirs 1321, 1322 and 1323, Each of the valves 1324, 1325, and 1326 are illustrated as three-position, four-way electrically actuated hydraulic valves. Valves 1325 and 1326, respectively, can be connected to pressure relief valves 1328 and 1329. The elements of the fluid valve subsystem 1320 as illustrated in Figure 13 arc exemplary and illustrative only, and other components, and numbers, arrangements, and connections of components can be used as desired. [0062] Pressure transducers PT or other pressure measuring devices 1340, 1342, 1344, 1346 and 1348 measure the fluid pressure in the hydraulic lines between the fluid valve subsystem 1320 and the cylinders 1370, 1380 and 1390. Control lines 1310 connect the pressure measuring devices 1340, 1342, 1344, 1346 and 1348 to the remote control display 1400. In addition, flow meters FM 1350, 1352, 1354, 1356, 1358 and 1360 measure the flow of hydraulic fluid to the cylinders 1370-1390, which can allow measuring the volume of fluid that is delivered to the cylinders 1370, 1380 and 1390. Although the system S includes both pressure transducers PT and flow meters FM, either the pressure transducers PT or the flow meters FM can be omitted if desired. Although expressed herein in terms of pressure transducers PT and flow meters FM, other types of pressure and flow measuring devices can be used as desired. [0063] Turning now to Figure 14, an exemplary indicator panel is illustrated for remote control display 1400 for the system S of Figure 13 In the following, the term 25 3067AP-Di "switch" will be used to indicate any type of control that can be activated or deactivated, without limitation to specific types of controls. Exemplary switches are toggle switches and push buttons, but other types of switches can be used. Pressure gauges 1402, 1404, 1406, and 1408 connected by control lines 1310 to the pressure transducers, such as the pressure transducers PT of Figure 13, indicate the pressure in various parts of the system S. Indicators on the panel include wellbore pressure gauge 1402, bearing latch pressure gauge 1404, pump pressure gauge 1406, and body latch pressure guage1408. The rotating control device or bearing latch pressure 1404 indicates the pressure in the chamber 600 at the end of the chamber where fluid is introduced to move the piston 220 into the latched position. The housing section or body latch pressure gauge 1408 indicates the pressure in the chamber 610 at the end of the chamber where fluid is introduced to move the piston 302 into the latched position. A switch or other control 1420 can be provided to cause the system S to manipulate the fluid valve subsystem 1320 to move the piston 302 between the latched (closed) and unlatched (open) positions. For safety reasons, the body latch control 1420 is preferably protected with a switch cover 1422 or other apparatus for preventing accidental manipulation of the control 1420. For safety reasons, in some preferred embodiments, an enable switch 1410 can be similarly protected by a switch cover 1412. The enable switch 1410 must be simultaneously or closely in time engaged with any other switch, except the Off/On control 1430 to enable the other switch. In one preferred embodiment, engaging the enable switch allows activation of other switches within 10 seconds of engaging the enable switch. This technique helps prevent accidental unlatching or other dangerous actions that might otherwise be caused by accidental engagement of the other switch. 100641 An Off/On control 1430 controls the operation the pump 1335. A Drill Nipple/Bearing Assembly control 1440 controls a pressure value produced by the pump 1335. The pressure value can be reduced if a drilling nipple or other thin walled apparatus is installed. For example, when the control 1440 is in the "Drill Nipple" position, the pump 1335 can pressurize the fluid to 200 PSI, but when the control is in the "Bearing Assembly" position, the pump 1335 can pressurize the fluid to 1000 PSI. Additionally, an "Off' position can be provided to set the pump pressure to 0 PSI. Other fluid pressure values can be used. For example, in one preferred embodiment, the "Bearing Assembly" position can cause pressurization depending on 26 3067AP-Dl the position of the Bearing Latch switch 1450, such as 800 PSI if switch 1450 is closed and 2000 PSI if switch 1450 is open. [00651 Control 1450 controls the position of the piston 220, latching the rotating control device 100 to the latch assembly 300 in the "closed" position by moving the piston 220 to the latched position. Likewise, the control 1460 controls the position of the auxiliary or secondary piston 222, causing the piston 222 to move to urge the piston 220 to the unlatched position when the bearing latch control 1460 is in the "open" position. Indicators 1470, 1472, 1474, 1476, 1478, 1480, 1482, 1484, 1486, and 1488 provide indicators of the state of the latch assembly and other useful indicators. As illustrated in Figure 14, the indicators are single color lamps, which illuminate to indicate the specific condition. In one preferred embodiment, indicators 1472, 1474, 1476, and 1478 are green lamps, while indicators 1470, 1480, 1482, 1484, 1486, and 1488 are red lamps; however, other colors can be used as desired. Other types of indicators can be used as desired, including multicolor indicators that combine the separate open/closed indicators illustrated in Figure 14. Such illuminated indicators are known to the art. Indicator 1470 indicates whether the hydraulic pump 1335 of Figure 13 is operating. Specifically, indicators 1472 and 1482 indicate whether the bearing latch is closed or open, respectively, corresponding to the piston 220 being in the latched or unlatched position, indicating the rotating control device 100 is latched to the latch assembly 300. Indicators 1474 and 1484 indicate whether the auxiliary or secondary latch is closed or open, respectively, corresponding to the piston 222 being in the first or second position. Indicators 1476 and 1486 indicate whether the body latch is closed or open, respectively, i.e., whether the latch assembly 300 is latched to the housing section 310, corresponding to whether the piston 302 is in the unlatched or latched positions. Additionally, hydraulic fluid indicators 1478 and 1488 indicate low fluid or fluid leak conditions, respectively. [00661 An additional alarm indicator indicates various alarm conditions. Some exemplary alarm conditions include: low fluid, fluid leak, pump not working, pump being turned off while wellbore pressure is present and latch switch being moved to open when wellbore pressure is greater than a predetermined value, such as 25 PSI. In addition, a horn (not shown) can be provided for an additional audible alarm for safety purposes. The display 1400 allows remote control of the latch assembly 210 and 300, as well as remote 27 3067AP-Di indication of the state of the latch assembly 210 and 300, as well as other related elements. [00671 Figure 18 illustrates an exemplary set of conditions that can cause the alarm indicator 1480 and horn to be activated. As shown by blocks 1830 and 1840, if any of the flow meters FM of Figure 13 indicate greater than a predetermined flow rate, illustrated in Figure 18 as 3 GPM, then both the alarm light 1480 and the horn will be activated. As shown by blocks 1820, 1822, 1824, 1826, and 1840, if the wellbore pressure is in a predetermined relative relation to a predetermined pressure value, illustrated in Figure 18 as greater than 100 PSI, and any of the bearing latch switch 1450, the body latch switch 1420, or the secondary latch switch 1460 are open, then both the alarm 1480 and the horn are activated. As shown by blocks 1810, 1814, 1815, 1816, and 1840, if the wellbore pressure is in a predetermined relative relationship to a predetermined pressure value, illustrated in Figure 18 as greater than 25 PSI, and either the pump motor is not turned on by switch 1430, the fluid leak indicator 1488 is activated for a predetermined time, illustrated in Figure 18 as greater than 1 minute, or the low fluid indicator 1478 is activated for a predetermined time, illustrated in Figure 18 as greater than 1 minute, then both the alarm 1480 and horn are activated. Additionally, as indicated by blocks 1810, 1811, 1812, 1813, and 1850, if the wellbore pressure is in a predetermined relative relationship to a predetermined pressure value, illustrated in Figure 18 as greater than 25 PSI, and either the body latch switch 1420 is open, the bearing latch switch 1450 is open, or the secondary latch switch 1460 is open, then the alarm indicator 1480 is activated, but the horn is not activated. The conditions that cause activation of the alarm 1480 and horn of Figure 18 are illustrative and exemplary only, and other conditions and combinations of conditions can cause the alarm 1480 or horn to be activated. [00681 Figures 15K, 15L, 15M, 15N, 150 and 16 illustrate an preferred embodiment in which measurement of the volume of fluid pumped into chambers 600 and 610 can be used to indicate the state of the latch assembly 300. Passageways 1501 and 1503 as shown in Figure 15K, corresponding to passageways 1101 and 1103 as shown in Figure I I A, allow hydraulic fluid to be pumped into chamber 600, causing piston 220 to move to the latched position. Passageways 1505 and 1509 as shown in Figure 15 L, corresponding to passageways 1105 and 1109, allow hydraulic 28 3067AP-DI fluid to be pumped into chamber 600, causing piston 220 to move to the unlatched position and piston 222 to move away from piston 220. Passageways 1507 and 1511 as shown in Figure 15M, corresponding to passageways 1107 and 1111 as shown in Figure 1IE, allow hydraulic fluid to be pumped into chamber 600, causing piston 222 to urge piston 220 from the latched to the unlatched position. Passageways 1517 and 1519 as shown in Figure 15N, corresponding to passageways 1117 and 1119 as shown in Figure 11 G, allow hydraulic fluid to be pumped into chamber 610, causing piston 302 to move to the latched position. Passageways 1521 and 1523 as shown in Figure 150, corresponding to passageways 1121 and 1123 as shown in Figure 11 H, allow hydraulic fluid to be pumped into chamber 610, causing piston 302 to move to the unlatched position. Ports 1610, 1620, 1630, 1640, and 1650 allow connection of hydraulic lines to passageways 1501, 1509, 1511, 1517 and 1521, respectively. By measuring the flow of fluid with flow meters FM, the amount or volume of fluid pumped through passageways 1501, 1509, 1511, 1517 and 1521 can be measured and compared to a predetermined volume. Based on the relative relationship between the measured volume value and the predetermined volume value, the system S of Figure 13 can determine and indicate on display 1400 the position of the pistons 220, 222 and 302, hence whether the latch assembly 300 is latched to the rotating control device 100 and whether the latch assembly 300 is latched to the housing section, such as housing section 310, as described above. [0069] In one preferred embodiment, the predetermined volume value is a range of predetermined volume values. The predetermined volume value can be experimentally determined. An exemplary range of predetermined volume values is 0.9 to 1.6 gallons of hydraulic fluid, including 2 gallon to account for air that may be in either the chamber or the hydraulic line. Other ranges of predetermined volume values are contemplated. [0070] Figure 17 illustrates an alternate preferred embodiment that uses an electrical switch to indicate whether the latch assembly 300 is latched to the housing section 310. Movement of the retainer member 304 by the piston 302 can be sensed by a piston 1700 protruding in the latching formation 311. The piston 1700 is moved outwardly by the retainer member 304, Movement of the piston 1700 causes electrical switch 1710 to open or close, which can in turn cause an electrical signal via 29 3067AP-m1 electrical connector 1720 to a remote indicator position system and to display 1400. Internal wiring is not shown in Figure 17 for clarity of the drawing. Any convenient type of switch 1710 and electrical connector 1720 can be used. Preferably, piston 1700 is biased inwardly toward the latch assembly 300, either by switch 1710 or by a spring or similar apparatus, so that piston 1700 will move inwardly toward the latch assembly 300 when the retainer member 304 retracts upon unlatching the latch assembly 300 from the housing section 310. [00711 The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and construction and the method of operation may be made without departing from the spirit of the invention. [00721 In particular, variations in the orientation of the rotating control device 100, latch assemblies 210, 300, housing section 310, and other system components are possible. For example, the retainer members 218 and 304 can be biased radially inward or outward. The pistons 220, 222, and 302 can be a continuous annular member or a series of cylindrical pistons disposed about the latch assembly. Furthermore, while the preferred embodiments described above have discussed rotating control devices, the apparatus and techniques disclosed herein can be used to advantage on other tools, including rotating blowout preventers. [00731 All movements and positions, such as "above," "top," "below," "bottom," "side," "lower," and "upper" described herein are relative to positions of objects as viewed in the drawings such as the rotating control device. Further, terms such as "coupling," "engaging," "surrounding," and variations thereof are intended to encompass direct and indirect "coupling," "engaging," "surrounding," and so forth. For example, the retainer member 218 can engage directly with the rotating control device 100 or can be engaged with the rotating control device 100 indirectly through an intermediate member and still fall within the scope of the disclosure, [0074] The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and 30 3067AP-DI construction and the method of operation may be made without departing from the spirit of the invention. [0075] Although the invention has been described in terms of preferred preferred embodiments as set forth above, it should be understood that these preferred embodiments are illustrative only and that the claims are not limited to those preferred embodiments. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in the invention, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein. [0076] The foregoing describes only preferred embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. [0077] The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "including" or "having" and not in the exclusive sense of "consisting only of. 31 3067AP-DI

Claims (27)

1. An apparatus, comprising: a latch assembly comprising: a retainer member movable between an unlatched position and a latched position; and a first piston movable between a first position and a second position, the first piston causing the retainer member to move to the latched position when the first piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the first piston is in the second position, wherein the latch assembly is remotely actuatable for moving the first piston to the latched position; and a measuring device coupled to the latch assembly, said measuring device used to indicate the position of the first piston.

2. The apparatus of claim 1, further comprising: a rotating control device, wherein the retainer member latches the rotating control device to the latch assembly when the retainer member is in the latched position.

3. The apparatus of claim 1, wherein the retainer member is radially compressed to move to the latched position.

4. The apparatus of claim 1, further comprising: a housing section, the latch assembly removably connectable to the housing section.

5. The apparatus of claim 1, wherein the retainer member is a C-shaped ring or a plurality of spaced-apart dog members.

6. The apparatus of claim 1, further comprising: a fluid line operatively coupled to the latch assembly for delivering a fluid to the latch assembly; 3067AP-D1 33 wherein the measuring device is coupled to the latch assembly with the fluid line, the measuring device measuring a fluid volume value for the fluid delivered to the latch assembly; and a comparator configured to compare the measured fluid volume value to a predetermined fluid volume value,

7. The apparatus of claim 6, wherein the latch assembly is unlatched when the measured fluid volume value is in a predetermined relative relationship to the predetermined fluid volume value.

8. The apparatus of claim 6, further comprising a display coupled to the comparator, the display comprising an indicator light.

9. The apparatus of claim 8, the indicator light comprising a multicolor light, wherein a first color of the multicolor light indicates the latch assembly is latched wherein a second color of the multicolor light indicates the latch assembly is unlatched.

10. The apparatus of claim 1, further comprising: a first fluid line operatively coupled to the latch assembly for delivering a fluid to the latch assembly; a second fluid line operatively coupled to the latch assembly for returning the fluid from the latch assembly, wherein the measuring device is coupled to the latch assembly with the second fluid line, the measuring device measuring a fluid pressure value for fluid returned from the latch assembly; and a comparator configured to compare the measured fluid pressure value to a predetermined fluid pressure value.

11. The apparatus of claim 10, wherein the latch assembly is latched when the measured fluid pressure value is in a predetermined relative relationship to the predetermined fluid pressure value. 3067AP-D1 34

12. The apparatus of claim 1, further comprising: a first fluid line operatively coupled to the latch assembly for delivering a fluid to the latch assembly; a second fluid line operatively coupled to the latch assembly for returning the fluid from the latch assembly; wherein the measuring device is coupled to the latch assembly with the second fluid line, the measuring device measuring a fluid flow rate value for the fluid returned from the latch assembly; and a comparator configured to compare the measured fluid flow rate value to a predetermined fluid flow rate value.

13. The apparatus of claim 12, wherein the latch assembly is latched when the measured fluid flow rate value is in a first predetermined relative relationship to the predetermined fluid flow rate value, and wherein the latch assembly is unlatched when the measured fluid flow rate value is in a second predetermined relative relationship to the predetermined fluid flow rate value.

14. The apparatus of claim 1, the latch assembly further comprising: a second piston positioned with the first piston and movable between a first position and a second position, wherein moving the second piston to the second position of the second piston urges the first piston into the second position of the first piston.

15. The apparatus of claim 14, wherein the second piston is hydraulically actuated.

16. The apparatus of claim 14, wherein the first piston and/or, where provided, the second piston is an annular piston.

17. An apparatus, comprising: a housing section; a rotating control device adapted for positioning with the housing section; and 3067AP-D1 35 a latch assembly latchable to the rotating control device, sealable with the rotating control device, and adapted to connect to the housing section, comprising: a retainer member movable between an unlatched position and a latched position, the retainer member latched with the rotating control device in the latched position; and a piston, movable between a first position and a second position, the piston causing the retainer member to move to the latched position when the piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the piston is in the second position; a latch position indicator system coupled to the latch assembly, comprising: a fluid line operatively coupled to communicate fluid to the latch assembly; a measuring device, coupled to the fluid line for measuring a fluid value; and a comparator, coupled to the measuring device, configured to compare the measured fluid value to a predetermined fluid value.

18. The apparatus of claim 17, wherein: the measured fluid value is a measured fluid volume value, and the predetermined fluid value is a predetermined fluid volume value; or the measured fluid value is a measured fluid pressure value, and the predetennined fluid value is a predetermined fluid pressure value; or the measured fluid value is a measured fluid flow rate value, and the predetermined fluid value is a predetermined fluid flow rate value.

19. An apparatus, comprising: a housing section; a rotating control device having a rotatable inner member and an outer member, and adapted to seal with the housing section; and a latch assembly latchable to the rotating control device, sealable with the rotating control device, and adapted to connect to the housing section, 3067AP-D1 36 wherein the latch assembly is emotely and hydraulically actuatable to latch the rotating control device with the housing section, and a latch position indicator system remotely and hydraulically coupled to the latch assembly.

20. The apparatus of claim 4 or 19, wherein the latch assembly is boltable to the housing section.

21. The apparatus of claim 19, wherein the latch position indicator system comprises a measuring device used to indicate the position of the latch assembly.

22. The apparatus of claim 21, wherein the measuring device is a meter.

23. The apparatus of claim 2 1, wherein the measuring device is a pressure transducer.

24. A method, comprising: providing a latch assembly comprising: a retainer member movable between an unlatched position and a latched position; and a first piston movable between a first position and a second position, the first piston causing the retainer member to move to the latched position when the first piston is in the first position and the first piston allowing the retainer member to move to the unlatched position when the first piston is in the second position; remotely actuating the latch assembly so as to move the first piston to the latched position; and indicating the position of the first piston using a measuring device coupled to the latch assembly.

25. An apparatus comprising a latch assembly, the apparatus being substantially as herein described with reference to any one or more of the accompanying drawings. 3067AP-D1 37

26. An apparatus comprising a housing section, the apparatus being substantially as herein described with reference to any one or more of the accompanying drawings.

27. A method of providing a latch assembly, the method being substantially as herein described with reference to any one or more of the accompanying drawings. Dated this 4th day of November 2013 WEATHERFORD/LAMB, INC. By FRASER OLD & SOHN Patent Attorneys for the Applicant 3067AP-DI