Patent Publication Number: US-10329853-B2

Title: Motion compensator system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/469,743 filed on Mar. 10, 2017, which is incorporated herein by reference in its entirety. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a compensator system in an extended position. 
       FIG. 2  is a perspective view of the compensator system in a retracted position. 
       FIG. 3  is an exploded view of the various components of the compensator system. 
       FIG. 4  is a perspective view of a safety shutoff system of the compensator system. 
       FIG. 5  is a schematic view of a tank assembly of the compensator system. 
       FIG. 6  is a perspective detail view of a filter manifold of the compensator system. 
       FIG. 7  is a front view of a lock assembly of the compensator system. 
       FIG. 8  is a front cutaway view of the lower compensator carriage with the locking assembly in an unlocked position. 
       FIG. 9  is a front view of the lock assembly in a locked position. 
       FIG. 10  is a front cutaway view of the lower compensator carriage with the locking assembly in the locked position. 
       FIGS. 11A and 11B  are schematic views of the safety shutoff system. 
       FIG. 12  is a detail schematic view of one compensator cylinder in the safety shutoff system. 
       FIG. 13  is a perspective view of a coil tubing lift frame attached to the compensator system. 
       FIG. 14  is a perspective view of a winching frame attached to the compensator system. 
       FIG. 15  is a perspective view of the winching frame. 
       FIG. 16  is a partially-exploded view of the winching frame showing the components of a fastener assembly. 
       FIG. 17  is a front detail view of the winching frame attached to the lower carriage assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Motion compensators are used on offshore drilling platforms to compensate for the wave action which results in vertical displacement of the drilling platform deck. Prior art motion compensators are described in U.S. Pat. No. 7,191,837, issued on Mar. 20, 2007, to Coles, which is incorporated herein by reference, and U.S. Pat. No. 6,929,071, issued on Aug. 16, 2005, to Moncus et al., which is incorporated herein by reference. A novel compensator system and method of use is disclosed herein. The compensator system includes: (i) the compensator, (ii) the carriage components that retain the compensator, (iii) a safety shut off system, and (iv) a locking mechanism. The carriage components assist in mounting the compensator to a derrick or crane. The carriage components also assist in mounting a load, such as a drill string or lift frame, to the compensator. The safety shut off system is configured to monitor the cylinders in the inner cylinder assembly. If one or more of these cylinders fails, the safety shut off system isolates the failed cylinder(s) so that operations can continue and distribute the load on the remaining operable cylinders until repair operations can be implemented. This prevents the compensator from failing. A failure in the compensator could result in the load being dropped, damaging both equipment and people who may be in the area. Additionally, the compensator system includes a locking mechanism which functions to lock the compensator system in a retracted position. The compensator system described herein is capable of supporting a load of up to 750 tons. 
       FIG. 1  illustrates one embodiment of the compensator system. Compensator system  10  includes an upper compensator carriage  12 , a cylinder carriage  14 , a lower compensator carriage  16 , an outer guide cylinder assembly  18 , and an inner compensator cylinder assembly  20 . The upper compensator carriage  12  is connected to the cylinder carriage  14 . Cylinder carriage  14  and lower compensator carriage  16  are configured to retain the outer cylinder assembly  18  and the inner cylinder assembly  20  in the compensator system  10 . Upper compensator carriage  12  is configured to be mounted to a derrick or crane. Lower compensator carriage  16  is configured to suspend a load, such as a drill string, to the compensator system. The compensator system  10  is configured to operate in a fully extended position shown in  FIG. 1 , a fully retracted position shown in  FIG. 2 , or any position therebetween. The operational position of the compensator system  10 , whether extended, retracted, or in an intermediate position, will be determined by the height of the deck from the seabed. The height of the deck from the seabed is determined by the water surface, which is subject to change due to wave action and/or tidal phases. 
     The upper compensator carriage  12  is configured to mount the compensator system  10  to a derrick or crane. The upper compensator carriage  12  includes lift eyes  22  each having central aperture  25  and side apertures  28 . Central aperture  25  is dimensioned to receive a fastener to attach the upper compensator carriage  12  to a derrick or crane. 
     The cylinder carriage  14  attaches to the upper compensator carriage  12  and retains the upper end of both the outer guide cylinder assembly  18  and the inner compensator cylinder assembly  20 . As shown in  FIG. 3 , the upper end of the cylinder carriage  14  includes mounting members  69 . In one embodiment, cylinder carriage  14  may include four mounting members  69 . Each mounting member  69  includes aperture  70 . Mounting members  69  connect the cylinder carriage  14  to the upper compensator carriage  12 . Mounting members  69  are positioned to align with the spaces between lift eyes  22  of the upper compensator carriage  12  so that apertures  70  in mounting member  69  align with central apertures  25  of the lift eyes  22 . Upper compensator carriage  12  and cylinder carriage  14  together form an upper carriage for the compensator system  10 . 
     Referring to  FIG. 3 , in one embodiment, a pin  94  is secured through side apertures  28  of each set of adjacent lift eyes  22  and aperture  70  of the corresponding mounting member  69  disposed between the adjacent lift eyes  22 . Each pin  94  may be locked in apertures  28  and  70  by affixing a mounting plate  98  over aperture  28  of the outer lift eye  22 . In this way, pins  94  connect the cylinder carriage  14  to the upper compensator carriage  12 . 
     With reference to  FIG. 3 , the lower compensator carriage  16  is configured to secure a load, such as a drill string, to the compensator system  10 . Lower compensator carriage  16  is also configured to retain the lower ends of outer guide cylinder assembly  18  and inner compensator cylinder assembly  20  (as described in more detail below). In the embodiment illustrated, lower compensator carriage  16  includes two mounting brackets  106  extending below from the remainder of lower compensator carriage  16 . Each mounting bracket  106  includes a mounting aperture  108  configured to receive a fastener, such as a pin, screw, bolt, rope, hoist, hook, or any other suitable fastener for attaching a load to the compensator system  10 . Mounting brackets  106  are centrally positioned in lower compensator carriage  16  such that when a load is mounted to mounting brackets  106 , the weight of the load is evenly distributed through the compensator system  10 . Each mounting bracket  106  also includes a locking pin aperture configured to receive part of a locking assembly (described in more detail below) and cylinder apertures configured to receive a fastener to connect the inner compensator cylinder assembly  20  and outer guide cylinder assembly  18  to the lower compensator carriage  16 . 
     Outer guide cylinder assembly  18  is connected to cylinder carriage  14  and lower compensator carriage  16 . The outer guide cylinder assembly  18  includes cylinders  162 . Cylinders  162  have an inner bore  163  defined by an inner bore wall. Cylinder  162  also has an enlarged external diameter  165  located at the lower end of cylinder  162 . The outer cylinder assembly  18  may include four cylinders  162 , with a pair of cylinders  162  located on either side of inner compensator cylinder assembly  20 . Outer cylinder assembly  18  also includes guide rods  166  and brackets  167 . Each bracket  167  is secured to a pair of adjacent cylinders  162 . Bracket  167  includes paired bracket mounts  168  for mounting the bracket  167  to cylinders  162 . Central portion  169  of bracket  167  interconnects bracket mounts  168 . Central portion  169  includes lower projection  171  having aperture  173 , which is disposed below bracket mounts  168 . Aperture  173  forms a through bore for locking the outer cylinder assembly  18  in a retracted position. Aperture  173  is dimensioned to receive a locking system (described below). Bracket  167  is positioned on the lower end of cylinder  162  and is retained on cylinder  162  by the enlarged diameter bottom portion of cylinder  162 . 
     Guide rod  166  is slidingly disposed in the inner bore  163  of cylinder  162 . Guide rod  166  includes an enlarged diameter upper portion  170  and length designations  172  along the length of guide rod  166 . Guide rods  166  are of a smaller diameter than the inner bore  163  of cylinder  162  and are allowed to freely slide vertically along the length of cylinder  162 . The upper end of cylinder  162  is closed. The lower end of cylinder  162  has an internal collar that reduces the diameter of the inner bore  163  at the bottom of cylinder  162 . Enlarged diameter upper portions  170  of guide rods  166  have a diameter that is greater than that of the remaining length of guide rods  166 . The diameter of enlarged diameter upper portion  170  is also greater than the diameter of the opening formed by the internal collar at the bottom of cylinder  162 , thereby retaining guide rods  166  in cylinders  162 . Length designations  172  provide an indication of the length of guide rod  166  extended below the bottom of cylinder  164 . In one embodiment, length designations  172  are numbers that correspond to the approximate number of feet of guide rod  166  that is extended below the bottom of cylinder  162 . In another embodiment, the length designations  172  are horizontal lines that represent a specific distance, such as each line representing a foot or meter. Cylinder  162  includes a mounting member  174  at the upper end. The mounting member  174  includes aperture  176 . Aperture  176  is dimensioned to receive a fastener to connect cylinder  162  to cylinder carriage  14 . Aperture  176  aligns with apertures of the cylinder carriage  14 . For example, the mounting member  174  of each cylinder  162  may fit between the two brackets of the cylinder carriage  14  to align aperture  176  of the cylinder  162  with apertures in each bracket. A fastener may then be secured through aperture  176  of each cylinder  162  and apertures in the brackets of the cylinder carriage  14  in order to secure each cylinder  162  of outer guide cylinder assembly  18  to cylinder carriage  14 . 
     Each guide rod  166  includes a mounting member  177  located on the bottom of guide rod  166 . Apertures  178  are located in mounting member  177  and are dimensioned to receive a fastener, such as a pin, bolt, or screw, to connect a lower end of each guide rod  166  to the lower compensator carriage  16 . For example, the mounting member  177  of each guide rod  166  may fit between the two brackets of the lower compensator carriage  16  to align aperture  178  of the guide rod  166  with apertures in each bracket. Additionally, when the guide rods  166  are in the retracted position shown in  FIG. 2 , aperture  173  of bracket  167  may be disposed between two brackets of the lower compensator carriage  16 , thereby aligning aperture  173  with the apertures in the brackets. In this position, the locking system (described below) is capable of engaging the aperture  173  and the apertures of the brackets to lock the compensator system  10  in the retracted position. 
     Referring to  FIG. 3 , fasteners, such as pins  182 , may be secured through apertures  178  of the mounting members  177  and the apertures in the brackets of lower compensator carriage  16 . Pins  182  may be locked in the apertures by affixing mounting plates  183  over the apertures in the brackets. In this way, pins  182  connect the lower compensator carriage  16  to outer guide cylinder assembly  18 . 
     With reference still to  FIG. 3 , inner compensator cylinder assembly  20  is also connected to the cylinder carriage  14  and the lower compensator carriage  16 . The inner cylinder assembly  20  includes cylinders  186 , compensator rods  188 , top plate  190 , bottom plate  192 , mounting brackets  194 , bottom plate apertures  196 , top plate apertures  198 , mounting bracket arms  202 , mounting arm apertures  204 , and fasteners  206 . In the embodiment illustrated, inner compensator cylinder assembly  20  includes four cylinders  186 . Cylinders  186  are hollow cylinders each housing a piston and partially housing a compensator rod  188 . A top plate  190  is positioned at the upper end of each cylinder  186  and a bottom plate  192  is located at the bottom end of each cylinder  186 . Inner compensator cylinder assembly  20  may be mounted to the cylinder carriage  14  with fasteners, such as pins, screws, or bolts, disposed through apertures in the top plate  190  and through apertures in a plate of the cylinder carriage  14 . Bottom plate  192  includes an aperture (not shown) and compensator rod  188  is slidingly disposed through this aperture. Compensator rods  188  have a smaller diameter than the hollow portion of cylinder  186  and are allowed to slide vertically along the length of cylinder  186 . Compensator rods  188  have an enlarged diameter section or piston (not shown) at its upper end that prevents compensator rod  188  from falling out of cylinder  186 . The piston of compensator rod  188  is larger in diameter than the aperture through bottom plate  192 , thereby retaining compensator rod  188  in cylinder  186 . The piston also creates an upper chamber and a lower chamber within the hollow portion of cylinder  186 . Bottom plate  192  includes at least one bottom member aperture  196 , which provides a fluid inlet to the lower chamber for a pressurized fluid. The pressure applied by the fluid in the lower chambers controls the position of the pistons and compensator rods  188  in cylinders  186 . The top plate apertures  198  fluidly connect the upper chambers of cylinders  186  to a filter manifold  300 . 
     Mounting brackets  194  are located at the bottom ends of compensator rods  188 . Each mounting bracket  194  includes at least two spaced-apart bracket arms  202 , with each bracket arm  202  including an arm aperture  204 . The bracket arms  202  are substantially parallel to one another with the arm apertures  204  substantially aligned. Compensator rods  188  are secured to lower compensator carriage  16  by sliding a bracket of lower compensator carriage  16  between bracket arms  202  of a mounting bracket  194 . Fastener  206  may then be secured through arm apertures  204  of compensator rods  188  and through apertures in the bracket of lower compensator carriage  16 . Fastener  206  may be any fastener known in the art, such as screws, bolts, pins, and the like. 
     In operation, compensator system  10  is retracted by flowing a pressurized fluid through bottom plate apertures  196  and into the lower chambers of cylinders  186  of inner compensator cylinder assembly. The increased pressure in the lower chambers forces the pistons at the upper ends of each compensator rod  188  upward within the cylinder  186 , which pulls the compensator rod  188  into cylinder  186  (upward direction). Conversely, compensator system  10  is extended by venting the pressurized fluid from the lower chambers of cylinders  186  through bottom plate apertures  196  (e.g., to the atmosphere or to an accumulator). In this position, the effect of gravity on a tool suspended below compensator system  10  pulls the pistons at the upper ends of each compensator rod  188  downward within the cylinder  186 , thereby pulling the compensator rod  188  outward from cylinder  186  (downward direction). As compensator rods  188  of the inner compensator cylinder assembly  20  extend from or retract into cylinders  186 , guide rods  166  of the outer guide cylinder assembly  18  will also extend from or retract into cylinders  162  to the same degree. The amount of movement may be determined by viewing length designations  172  on guide rods  166 . In one embodiment, the length designations  172  are numbers representing approximately one-foot intervals. In one embodiment, the enlarged diameter upper portion  170  on guide rods  166  reach the end of cylinder  162  approximately 3 inches before compensator rods  188  reach the end of cylinders  186 . 
     With reference now to  FIG. 4 , compensator system  10  further includes a safety shutoff assembly  207 , which connects a tank assembly containing a pressurized gas to the lower chambers of cylinders  186  in the inner compensator cylinder assembly  20 . The safety shutoff system  207  includes numerous valves and actuators. For example, safety shut off system  207  may include valves  208 , each having a valve outlet  210  and a valve inlet  212 , upper hammer union  216 , connections  217 , lower hammer union  218 , and actuator  219 . In one embodiment, safety shutoff system  207  includes three valves  208 . Valves  208  may be piston operated ball valves. Valve inlets  212  and valve outlets  210  may each be connected to valves  208  with lower hammer unions  218  and upper hammer unions  216 , respectively. Each valve  208  may be fluidly connected to the tank assembly (described below) through valve inlet  212 . Each valve  208  may be fluidly connected to compensator manifold  221  through valve outlet  210  and one of the connector pipes  220 . Each valve  208  may be connected to one of the pipes  220  through the upper hammer union  216 . Compensator manifold  221  includes outlets  222  and inlets  223 . In the illustrated embodiment, compensator manifold  221  includes three inlets  223  and four outlets  222 . Each pipe  220  is connected to one of the inlets  223 . The compensator manifold  221  also has a mounting bracket  224  for connecting the compensator manifold  221  to the upper end of two cylinders  162  on one side of the outer guide cylinder assembly  18  via fasteners, such as screws and washers. 
     Cylinders  186  of the inner compensator cylinder assembly  20  are fluidly connected to the compensator manifold  221  through actuator assemblies  231 ,  232 ,  246 , and  248 . Each actuator assembly is associated with one of the cylinders  186 . Pipes  225  connect the outlets  222  of compensator manifold  221  to the actuator assemblies for each cylinder  186 . Hammer unions may be used to connect certain actuator assemblies to the compensator manifold  221 . For example, first actuator assembly  231  and second actuator assembly  232  are connected to the compensator manifold via pipe  225  and an elbow joint, while third actuator assembly  246  and fourth actuator assembly  248  are each connected to the compensator manifold  221  via pipes connected with a hammer union. 
     Actuator assemblies  231 ,  232 ,  246 , and  248  each include an actuator  229  and a compensator valve  230  connected by mounting member  243 . Each compensator valve  230  includes three fluid ports. One fluid port leads to outlet  222  of compensator manifold  221 , another fluid port leads to the associated cylinder  186 , and the third fluid port is a vent leading to the atmosphere. In one embodiment, each compensator valve  230  is a 3-way ball valve. In another embodiment, each compensator valve  230  is a piston operated 3-way ball valve. 
     Referring to  FIGS. 1-3 , the compensator valves  230  are connected to cylinders  186  through pipe  242  (shown in  FIGS. 1 and 3 ). Each pipe  242  is fluidly connected to a fluid port of one of the compensator valves  230  and to the bottom plate apertures  196  of the cylinders  186  via a connecting member. Pipe  242  may be made up of more than one pipe member. Additionally, the pipe members of  242  may be connected to one another with hammer unions. Each actuator assembly  231 ,  232 ,  246 , of  248  and its associated compensator valve  230  is operatively connected to only one cylinder  186  and therefore controls the flow of fluid to and from the cylinder  186  with which it is fluidly connected. 
     With reference again to  FIG. 4 , safety shutoff assembly  207  further includes control block  234 , which is connected to each of the valves  208  and  230  through actuators  219  and  229 , respectively, via the connections  217 . Connections  217  may be electrical, pneumatic, or hydraulic connections. In one embodiment, the actuators  219  and  229  are pneumatic. In operation, control block  234  controls the setting of each valve  208  and  230  by transmitting signals to actuators  219  and  229 , respectively. The setting signal transmitted by control block  234  may cause actuators  219  and  229  to open and/or close one or more fluid ports in valves  208  and  230 , respectively. The setting transmitted by control block  234  may be in response to a manual input from a user. Alternatively, the setting transmitted by control block  234  may be automatically generated in response to a predefined condition detected by one or more meters or other devices in communication with control block  234 . If one or more of cylinders  186  fail, control block  234  activates the appropriate actuator assembly  231 ,  232 ,  246 , and  248  in order to change the operative configuration of compensator valve  230  and isolate the failed cylinder  186 . In this way, the safety shutoff assembly  207  allows continued operation of the compensator system  10  even when one of the cylinders  186  fails. 
     With reference to  FIG. 5 , tank assembly  249  of compensator system  10  may be located on the deck of the platform or rig. The tank assembly  249  is a pressurized fluid source; it supplies pressurized fluid to the lower chambers of cylinders  186  through safety shut off assembly  207  to control the position of the internal pistons and associated compensator rods  188 . The tank assembly includes lines  250 , control panel  252 , valves  254 , pipes  255 , valves  256 , valves  257 , valves  258 , tanks  260 , lines to control panel  262 , and manifold  266 . Tank assembly  249  is connected to the safety shut off assembly  207  through lines  250 . Lines  250  may be fluidly connected to valve inlets  212  of valves  208  on one end and to valves  254  on the other end. In one embodiment, lines  250  are stainless steel braided hose. 
     Valves  254  are connected to lines  250  on one end and line  262  on the other. Line  262  is connected to valves  254 , valves  256 , and control panel  262 . Valves  256  connect to valves  257 , which connect to lines  255 . Lines  255  are connected to valves  257  on one end and valves  258  on the other. Valves  258  are connected to manifold  266 . The one or more inlets of manifold  266  are fluidly connected to tanks  260 . The outlets of manifold  266  are fluidly connected to valves  258 . Control panel  252  allows a user to control the flow of the pressurized fluid into the lower chambers of the cylinders  186 , which determines the position of compensator rods  188  between the fully extended position and the fully retracted position. Additionally, the control panel  252  alerts when a cylinder has failed. When a cylinder fails, the appropriate valves  254 ,  256 ,  257 , and/or  258 , which are all located on the deck, may be closed off by an operator. Tanks  260  may contain a pressurized gas or liquid that can control the pressure in lower chambers of cylinders  186 , thereby controlling the positioning of compensator rods  188  and the extension or retraction of the compensator system  10 . In one embodiment, the tanks  260  contain nitrogen gas. 
     Referring to  FIG. 6 , the compensator system  10  also includes one or more filter manifolds  300  fluidly connected to the top plate apertures  198  of cylinders  186 . Each filter manifold  300  includes inlets  302 , outlets  304 , and filter caps  308 . The inlets  302  are fluidly connected to the top plate apertures  198  of cylinders  186 . The outlets  304  vent to the atmosphere. Filter caps  308  are disposed within outlets  304  and prevent the outlets  304  from getting clogged. As shown in  FIG. 3 , the filter manifolds  300  are connected to top plate apertures  198  via pipe  310  and adapter  312 . 
     With reference to  FIGS. 7 and 8 , lock assemblies  267  are attached within lower compensator carriage  16 . When engaged, lock assemblies  267  retain compensator system  10  in the fully retracted position shown in  FIG. 2 . Lock assemblies  267  may be operated with a gas, such as nitrogen. Each lock assembly  267  includes lock housing  268 , locking pin  270 , enlarged diameter portion  271  of locking pin  270 , locking plug  274 , and reduced diameter portion  272  of locking plug  274 . Lock housing  268  is mounted to brace  273  of lower compensator carriage  16  with fasteners  281 . In one embodiment, fasteners  281  are bolts, pins, or screws. Lock housing  268  includes a bore, with an aperture located at one end. Lock housing  268  is mounted to brace  273  such that the aperture is directed away from the center of the lower compensator carriage  16 . Locking pin  270  includes an enlarged diameter portion  271  that is dimensioned such that it has a larger diameter than the aperture of lock housing  268 . The enlarged diameter portion  271  of locking pin  270  is connected to the reduced diameter portion  272  of locking plug  274 . Both enlarged diameter portion  271  of locking pin  270  and reduced diameter portion  272  of locking plug  274  are dimensioned so they can move through locking pin aperture  154  of the mounting bracket  106  of the lower compensator carriage  16 . Locking plug  274  is dimensioned to be received in apertures  275  in brackets  276  of the lower compensator carriage  16  and aperture  173  of the bracket  167  of the outer guide cylinder assembly  18 . The locking pin  270  is capable of being extended or retracted in lock housing  268 . When locking pin  270  is in a fully retracted position in lock housing  268  (shown in  FIG. 7 ), the compensator system  10  is in an unlocked position and the guide rods  166  of the outer guide cylinder assembly  18  are able to slide relative to cylinders  162 . In the unlocked position, the locking plug  274  is not positioned in aperture  173  of bracket  167  of the outer guide cylinder assembly  18  or in apertures  275  of outermost brackets  276  of the lower compensator carriage  16  (as shown in  FIG. 8 ). 
     Referring now to  FIGS. 9 and 10 , locking pin  270  may slide out of lock housing  268  in a locked position. In the locked position, locking plug  274  is disposed through apertures  275  of brackets  276  of the lower compensator carriage  16  and through aperture  173  of bracket  167  of the outer guide cylinder assembly  18 . Because locking plug  274  engages aperture  173 , the outer guide cylinder assembly  18  is not capable of movement in the locked position. Instead, outer guide cylinder assembly  18 , and in turn inner compensator cylinder assembly  20 , is locked in the fully retracted position shown in  FIG. 2 .  FIGS. 7 and 8  show the lock assemblies  267  and compensator system  10  in the unlocked position, while  FIGS. 9 and 10  show the lock assemblies  267  and compensator system  10  in the locked position. 
       FIGS. 11A and 11B  illustrate the flow of fluid within compensator system  10 . A pressurized fluid is stored in tanks  260 . Tanks  260  are fluidly connected to each of the compensator cylinders  186  through manifold  266 , lines  250 , valves  208 , compensator manifold  221 , and compensator valves  230 . Each compensator cylinder  186  is fluidly connected to a filter manifold  300 . In one embodiment, a tank valve  319  is positioned on each fluid line leading from tank  260  to manifold  266 . In operation, only a single tank valve  319  is opened at a time. In other words, one tank  260  provides sufficient flow of the pressurized fluid to contract the compensator system  10 ; the second tank  260  is a secondary tank that may be filled with the pressurized fluid while the first tank  260  is feeding the cylinders  186 . 
     Referring to  FIG. 12 , each compensator cylinder  186  includes piston  320  secured to the upper end of compensator rod  188 . Piston  320  is housed within cylinder body  321  of cylinder  186  to define upper chamber  322  and lower chamber  324 . To retract compensator system  10 , one of the tank valves  319  is opened and actuators  229  and  219  set valves  230  and  208  to allow a pressurized fluid to flow from tanks  260  through manifold  266 , lines  250 , valves  208 , compensator manifold  221 , compensator valves  230 , pipe  242 , bottom plate aperture  196 , and into lower chamber  324  of compensator cylinder  186 . Specifically, compensator valve  230  may be placed in a feed setting in which a fluid port leading to compensator manifold  221  is open, a fluid port leading to lower chamber  324  is open, and a fluid port leading to the atmosphere is closed. This increases the pressure within lower chamber  324 , and in response, piston  320  moves upward. As piston  320  moves upward, any fluid within upper chamber  322  (e.g., air, another gas, or liquid) is vented through top plate aperture  198  and filter manifold  300  to the atmosphere. To expand compensator system  10 , actuators  229  set compensator valves  230  to a vent setting in which the fluid port leading to compensator manifold  221  is closed, the fluid port leading to lower chamber  324  is open, and the fluid port leading to the atmosphere is open. In this way, the fluid within lower chamber  324  of compensator cylinder  186  is vented to the atmosphere as piston  320  moves downward within cylinder  186  in response to gravitational forces imposed by a tool suspended from compensator system  10 . When piston  320  moves downward, a vacuum is created within upper chamber  322 , which pulls air from the atmosphere through filter manifold  300  and through top plate aperture  198  into upper chamber  322 . 
     Compensator system  10  may detect a failure of one of the compensator cylinders  186 . In one embodiment, a pressure sensor is in fluid communication with each lower chamber  324 . If a pressure reading from any of the lower chambers  324  is below a threshold value (e.g., below 1,500 psi, below 1,000 psi, below 500 psi, below 250 psi, or any subrange therein) with the associated compensator valve  230  in the feed setting, the associated compensator cylinder  186  is a failed compensator cylinder. 
     In response to a detected failure, the failed compensator cylinder  186  may be isolated by adjusting the compensator valve  230  associated with that cylinder. The adjustment to the compensator valve  230  may involve placing the valve in the vent setting (i.e., closing the fluid port leading to compensator manifold  221  and opening both the fluid port leading to the atmosphere and the fluid port leading to the lower chamber  324  of cylinder  186 ). The compensator valve  230  may be adjusted manually by a user, or by actuator  229  in response to a manual command from a user or in response to an automated command. With the compensator valves  230  of the other compensator cylinders  186  operating normally, compensator system  10  may continue to expand and retract in response to changes in the distance between the sea floor and a floating vessel on which it rests. The failed compensator cylinder  186  may remain isolated until a time convenient for repair work. 
     Compensator system  10  may be used with coil tubing as shown in  FIG. 13  or with winching frames, wire line, or e-line setups as shown in  FIG. 14 . 
     With reference to  FIG. 13 , for use with coil tubing applications, the lower compensator carriage  16  is connected to the coil tubing lift frame  400 . Coil tubing lift frame  400  includes upper portion  402 , spaced apart arms  404 , and bottom portion  406 . The upper portion  402  has spaced apart arms  404  located on each side of the upper portion  402 . Spaced apart arms  404  are connected to the upper portion  402  of the coil tubing lift frame  400  at their upper end. Spaced apart arms  404  are connected to each side of the bottom portion  406  at their lower ends. Bails  408  may be connected to the bottom portion  406  of coil tubing lift frame  400 . The upper portion  402  of coil tubing lift frame  400  includes mounting brackets  410 , which may be secured to mounting brackets  106  of the lower compensator carriage  16 . For example, fasteners may be secured through mounting apertures  108  of mounting brackets  106  in lower compensator carriage  16  and through apertures in mounting brackets  410  of coil tubing lift frame  400 . 
       FIG. 14  illustrates compensator system  10  connected to winching frame  500 . Winching frame  500  has a winch  502  connected to its bottom side. Fastener  504  is suspended from winch  502 . In one embodiment, fastener  504  is a shackle. Winching frame  500  may also have bails  408  connected thereto. 
     With reference to  FIG. 15 , winching frame  500  may include lower mounting brackets  506  and  508  and upper mounting brackets  510  and  512 . Lower mounting brackets  506  and  508  include apertures  524  and  536 , respectively. Apertures  524  and  536  are used to receive a fastener for securing bails  408  to winching frame  500 . Upper mounting brackets  510  and  512  include apertures  532  and  552 , respectively. Apertures  532  and  552  are used to receive a fastener for securing winching frame  500  to lower compensator carriage  16 . 
     With reference to  FIG. 16 , fastener assemblies  576  are secured in apertures  532  and  552  to connect the winching frame  500  to the lower compensator carriage  16  and secured in apertures  524  and  536  to connect the bails  408  to the winching frame  500 . Each fastener assembly  576  is a locking system that requires two or more aligned apertures to function properly. Fastener assembly  576  includes pin  578 , slide  580 , pin bracket  582 , fasteners  586  (such as screws or bolts) to mount the pin bracket  582  to a first bracket surrounding a first aperture, washers  588  to be used with fasteners  586 , flange  590  positioned about a second aperture in a second bracket, fasteners  592  (such as screws or bolts) to mount the flange  590  about the second aperture, and washers  594  to be used with fasteners  592 . 
     Pin bracket  582  includes slots located along the length of the pin bracket  582  but the slots do not extend to the ends of pin bracket  582 . Pin bracket  582  is a hollow cylinder with one enclosed end. Pin bracket  582  includes a flange that extends around its open end. Slide  580  is located within the slots of pin bracket  582  and is configured to slide along the slots. Slide  580  has ends that are larger than its central portion, which is retained in the slots of the pin bracket  582 . The ends of slide  580  are larger than the slots in pin bracket  582 , which retains the slide in pin bracket  582 . Pin  578  is placed in pin bracket  582  so that the pin  578  is positioned between the slide  580  and the open end of pin bracket  582 . In one embodiment, slide  580  is secured to the end of pin  578 , such as with a fastener, bolt, or screw. Pin bracket  582  is connected to the upper mounting bracket  510  of the winching frame  500 . To connect pin bracket  582  to the upper mounting bracket  510 , washers  588  are placed on fasteners  586 . Fasteners  586  are then secured in apertures in the flange of pin bracket  582  and secured in apertures surrounding aperture  532  of upper mounting bracket  510 . Flange  590  is placed about aperture  552  on the opposite side of upper mounting bracket  512 . Washers  594  are placed on fasteners  592 . Fasteners  592  are then placed through apertures in flange  590  and secured in apertures surrounding aperture  552  of upper mounting bracket  512 . To engage the fastening assembly  576 , the slide  580  is moved inward to insert pin  578  through aperture  532  of the upper mounting bracket  510  and into aperture  552  of upper mounting bracket  512 . 
     As shown in  FIG. 17 , winching frame  500  is secured to the lower compensator carriage  16  using fastener assemblies  576 . Mounting brackets  106  of lower compensator carriage  16  are positioned between the pairs of upper mounting brackets  510  and  512  of winching frame  500  such that mounting apertures  108  of lower compensator carriage  16  are aligned with apertures  532  and  552  of upper mounting brackets  510  and  512  of winching frame  500 , respectively. Slides  580  of each fastener assembly  576  are then transferred in an inward direction toward upper mounting brackets  510 . Pins  578  slide through apertures  532 ,  108 , and  552 , thereby securing winching frame  500  to lower compensator carriage  16 . To remove the winching frame  500  from the lower compensator carriage  16 , the slides  580  are moved in the opposite direction away from upper mounting brackets  510 , thereby sliding pins  578  out of apertures  532 ,  108 , and  552  and back into the pin brackets  582 . 
     While the installation and use of fastener assembly  576  is described herein in reference to winching frame  500 , fastener assembly  576  may be used in any application in which a lift eye is secured between two braces with apertures of the lift eye and each brace aligned. Fastener assemblies  576  remain secured to and aligned with the associated aperture in a locked position and in an unlocked position. This provides safety advantages over conventional fasteners, which involve loose components that may fall and result in injury to workers. 
     For example, fastener assemblies  576  may be secured in central aperture  25  of lift eyes  22  in the upper compensator carriage  12  for suspending compensator system  10  from a crane or derrick (shown generally in  FIGS. 1-3 ). Upper compensator carriage  12  and fastener assemblies  576  allow compensator assembly  10  to be connected directly to the crown block without the need for elevators. This arrangement reduces the height of the compensator system  10  over conventional systems. 
     While the illustrative forms disclosed herein have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the example and descriptions set forth herein, but rather that the claims be construed as encompassing all the features of patentable novelty which reside herein, including all features which would be treated as equivalents thereof by those skilled in the art to which this disclosure pertains.