Patent Publication Number: US-11655926-B2

Title: Hot swappable fracturing pump system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/436,189, filed Jun. 10, 2019, the entire disclosure of which is hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to fracking and well workover operations. 
     BACKGROUND 
     A subterranean formation surrounding a well may be fractured to improve communication of fluids through the formation, for example, to/from the well. Fracturing typically uses multiple high-pressure, high-flow pumps to send high-pressure fluid downhole. The high-pressure and high-flow pumps are often plumbed to a manifold called a “missile” in a parallel configuration to achieve sufficient flow-rates and pressures to fracture the formation. The pressure in the manifold, particularly during fracking operations (i.e., frac pressure), is very high. If a leak were to develop, or the equipment to fail, it could be injurious to personnel close to manifold. The area near the manifold where a worker could be injured is sometimes referred to as the “red zone.” 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram of an example well fracking site. 
         FIG.  2    is a schematic diagram of an example connection configuration that can be used with aspect of this disclosure. 
         FIGS.  3 A- 3 B  are perspective views of an example connector shown closed ( FIG.  3 A ) and open ( FIG.  3 B ). 
         FIGS.  4 A- 4 B  are top-down views of the example connector of  FIGS.  3 A- 3 B  shown closed ( FIG.  4 A ) and open ( FIG.  4 B ). 
         FIG.  5    is a half side cross-sectional view of the example connector of  FIGS.  3 A- 3 B  in the closed position. 
         FIG.  6    is a partial perspective view of the example connector of  FIGS.  3 A- 3 B  with portions removed to show soft stops. 
         FIG.  7    is a side perspective view of the example connector of  FIGS.  3 A- 3 B . 
         FIGS.  8 A- 8 B  is a perspective view and a half cross-sectional view, respectively, of an example drain assembly. 
         FIG.  9    is a block diagram of a controller that can be used with aspects of this disclosure. 
     
    
    
     Like reference numbers in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     During fracturing operations, the “missile” or frac manifold has multiple connected pumps. Typically, the entire system must be depressurized to remove or change-out a pump, for example, if the pump needs maintenance, fails, or is no longer needed. The depressurization, disconnection, reconnection, and depressurization process can take a significant amount of time. This disclosure describes an example system that allows disconnections/connections of pumps to the manifold to be made without depressurizing the manifold and associated fluid lines. In other words, pumps can be “hot swapped.” Moreover, the pumps can be disconnected and connected without the need for personnel near the high pressure aspects of the manifold, i.e., without placing personnel in the dangerous “red zone.” 
       FIG.  1    is a schematic diagram of an example well site  1  arranged for fracking. The well fracking site  1  includes tanks  2 . The tanks  2  hold fracking fluids, proppants, and/or additives that are used during the fracturing process. The tanks  2  are fluidically coupled to one or more blenders  3  at the well site  1  via fluid lines (the one or more pipes, hoses, tubing and other types of fluid lines that define a fluid path). The blenders mix the fracking fluids, proppants, and/or additives prior to being pumped into the well  4 . The blenders  3  are fluidically coupled to a fracturing manifold  7 , or “missile.” One or more fracking pumps  5  are also fluidically coupled to the manifold  7 ; for example, fracking pumps  5   a ,  5   b , and  5   c  may be fluidically coupled to the manifold  7 , as shown in  FIG.  1   . The manifold  7  routes the blended fluid to the pumps  5 , which then increase the pressure of the fluid to fracking pressure (i.e., the pressure at which the target formation fractures). Then, the flow from the pumps is comingled in the manifold  7  and directed into the well  4 . A data van  6  is electronically connected to the tanks  2 , the blenders  3 , the well  4 , and the fracking pumps  5 . The data van  6  includes a controller  51  that controls and monitors the various components at the well site  1 . The controller  51  is in communication with various component of the fracking site  1  through one or more communication links  53 . 
     While a variety of components have been described in the example well site  1 , not all of the described components need be included. In some implementations, additional and/or different equipment may also be included. Also, the well  4  can be an onshore or offshore well. In the case of an offshore well, including subsea wells and wells beneath lakebeds or other bodies of water, the well site  1  is on a rig or vessel or may be distributed among several rigs or vessels. 
       FIG.  2    is a schematic of an example fracturing manifold  7  with multiple connection points  102  for connecting the fracking pumps  5 , which are each carried on a truck  8 ; for example, the fracking pumps  5   a  and  5   b  carried on the trucks  8   a  and  8   b , respectively, may each be connected to one of the connection points  102 . The manifold  7 , itself, is often configured on a skid that can be transported as a unit or integrated with a trailer that can be towed to the well site. The concepts herein encompass a system that allows the fracturing pumps  5  to be connected to and disconnected from the fracturing manifold  7  while fracturing fluid in the manifold  7  is at pressure, in certain instances at or near fracturing pressure, and/or while the other pumps  5  are being operated to pump fracturing fluid. The fracking trucks  8  can back into a perspective location, and without a worker needing to be between the truck and manifold  7 , a pump  5  can be fluidically and mechanically connected at a connection point  102 . Similarly, when a pump  5  is to be removed, the pump  5  can be disconnected from the manifold  7 , and allow the truck  8  leave the manifold  7 , without a worker needing to be between the truck and manifold. The workers do not need to physically connect/disconnect hoses or make/break connectors when removing, adding or swapping pumps  5 , allowing the workers can remain away from the “red zone.” In certain instances, the connection is made entirely automatically, without worker intervention. 
     As illustrated, the manifold  7  has multiple connection points  102  (two shown, but in practice, many more are provided—often  14  to  20  arranged on both sides of the manifold  7 ). The connection point  102  includes two sets of fluid lines—a high pressure side and a low pressure side. The fluid line of the high pressure side has a high side valve  44 , a bleed line  48  and a high side connector  106  and is connected to the high pressure fluid line  216 . The high pressure fluid line  216  is fluidically coupled to the well. It collects pumped fluid from each pump  5  and directs the pumped fluid to the well. The fluid line of the low pressure side has a low side valve  46  and a low side connector  112 , and is connected to the low pressure fluid line  218 . The low pressure fluid line  218  is fluidically coupled to the blender. It directs the blended frac fluid to the pumps  5  so that the fluid can be pumped. The high side valve  44  can be closed to seal against pressure in the manifold  7  in the high pressure line  216  to the well, thus isolating the connection point  102  from the pressure in the manifold  7  produced by the other connected pumps. The low side valve  46  can be closed to seal against pressure in the manifold  7  in the low pressure line  218  from the blenders, thus isolating the connection point  102  from the low pressure supply of frac fluid. The valves  44 ,  46  can be manual or, in certain instances, either or both can be actuable in response to a signal to open/close. Actuable valves  44 ,  46  enable the operation to be controlled by the controller  51 . Bleed line  48  enables draining high pressure fluid between the valve  44  and high side connector  106 . The bleed line  48  can be integrated with the valve  44 , the high side connector  106  or can be valved in the line between the two. In certain instances, the bleed line  48  is actuable to open in response to a signal (e.g., by use of an actuable valve). Also, while the connection point  102  has been illustrated and described as having a single valve for each of the high and low pressure sides, alternative or additional valve configurations can be used without departing from this disclosure. For example, particularly on the high pressure side, a second valve can be included in series with the first valve. Adding a second valve in series with the first valve allows for a double block and bleed or a double block and monitor configuration. 
     The high pressure side connector  106  is configured to connect/disconnect the discharge line  12   b  (i.e., discharge) of a pump  5  on a frack truck  8  to the manifold  7 . When connected, the high pressure side connector  106  secures to and seals with the discharge line  12   b , and is capable of handling the high pressure provided by the pump  5  during the fracturing treatment. In certain instances, the high side connector  106  is actuable in response to a signal to connect/disconnect, which enables the operation of the high side connector  106  to be controlled by the controller  51 . The low pressure side connector  112  can be the same type of connector as the high side connector  106  or another type of connector. Typically, though, the low pressure side connector  112  need only be configured to seal to the lower pressure of the low pressure line  12   a  (i.e., suction) of the pump  5  (and not the high pressure produced by the pump  5  or in the manifold). As discussed in more detail below, in certain instances, the low pressure side connector  112  is a male or female stab type connector. The connectors  106 ,  112  can be mounted at a specified height off the ground to align to the fluid lines from the pump  5 . In some implementations, one or both of the connectors  106 ,  112  can be mounted on an adjustable platform that can be adjusted to suit different configurations of trucks. 
     As illustrated, a first high pressure side pressure sensor  210   a  is positioned to sense internal pressure on the side of the valve  44  attached to the high side connector  106 . A second high pressure side pressure sensor  210   b  detects internal pressure on a side of the valve exposed to the pressure within the high pressure line  216  of the fracking manifold  7 . A similar arrangement of pressure sensors are provided on the low pressure side, with a first low pressure side pressure sensor  212   a  positioned to sense internal pressure on the side of the valve  46  attached to low side connector  112 . A second low pressure side pressure sensor  202   b  is positioned to detect internal pressure on a side of the valve exposed to pressure within the low pressure line  218  of the fracking manifold  7 . In certain instances, the pressure sensors  210   a ,  210   b ,  212   a ,  212   b  can be used to implement electronic interlocks to prevent the valve  44  and/or valve  46  from being opened under pressure or the high side connector  106  and/or low side connector  112  from disconnecting under pressure. For example, depending on the formation, frac pressure in the high pressure fluid line  216  can reach 15 thousand pounds per square inch (ksi) or more. If the controller  51  detects, with the second pressure sensor  210   b , such a high pressure and detects, with the first pressure sensor  210   a , a much lower pressure (e.g., near atmospheric), then controller  51 , based on output from the sensors  210   a ,  210   b  can effectuate an interlock to prevent the valve  44  from opening. After a fracturing pump at the connection point  102  has been pressurized, the first pressure sensor  210   a  and second pressure sensor will detect similar pressures, and the controller may allow valve  44  to open, but prevent the high side connector  106  from disconnecting. The pressure differential threshold at which the controller  51  effectuates the interlock of the valve  44  can be specified to the controller  51 . Similarly, the pressure threshold, over which the controller  51  prevents operation of the connector  106  can also be specified to the controller  51 . More details on example interlocks are described throughout this disclosure. 
     In some implementations, the high side connector  106  includes a guide cone  110  mounted to a housing of the high side connector  106 . The guide  110  guides the discharge line  12   b  of the fracturing pump  5  align with the high side connector  106 . For example, in instances where the fracturing pump  5  is mounted to a fracturing truck  8 , the truck  8  can back up to the fracturing manifold  7  and “stab” the discharge line  12   b  into the connector  106 . The guide  110  has a conical funnel shape that has a narrower end nearer the connector  106  and a wider end opposite the narrower end. The conical shape of the guide  110  drives the discharge line  12   b  into concentric alignment with the high side connector  106 , allowing the discharge line  12   b  to be concentrically received within the connector  106 . While described primarily with a funnel shape, other shapes (e.g., pyramidal or other) or other guidance features can be used without departing from this disclosure. In certain instances, the discharge line  12   b  or connection point  102  can have an in-line flex coupling or otherwise have flexibility to enable flex to account for misalignment when the discharge line  12   b  is stabbed into the high side connector  106 . Thus, the truck  8  with the pump  5  will need to back into proximity to the connection point  102 , but need not precisely position with respect to the high side connector  106 . In certain instances, the discharge line  12   b  and suction line  12   a  can be affixed, relative to one another, near their free ends by a strut or some other structure, so that when the discharge line  12   b  has been concentrically aligned by the guide cone  110 , the position of the suction line  12   a  is likewise concentrically aligned to stab into the low side connector  112  as the discharge line  12   b  stabs into high side connector  106 . Such an arrangement can be implemented with only the guide cone  110  on the high side connector  106 , and no guide cone on the low side connector  112 . Although not shown in  FIG.  2   , the low pressure side can, in certain instances, have a guide cone  110  on low side connector  112  to facilitate alignment of the suction line  12   a  with low side connector  112 . 
     In certain instances, the hardware of the connection points  102 , including the valves  44 ,  46 , the connectors  106 ,  112 , the sensors and other related components can be mounted on a trailer or skid  220  separate from the manifold  7 . The skid  220  can be set beside the manifold  7 , and fluid connections made-up between the fluid lines on the skid  220  and the manifold  7  to establish the connection points  102  as connection points to the manifold  7 . The hardware for each connection point  102  can be on a separate skid  220 , or a single skid  220  can carry the hardware for more than one connection point  102 . For example, in certain instances, a skid  220  may carry the hardware for a pair of connection points  102 . In certain instances, one, two or three skids may carry the hardware for all the connection points  102  on one side of the manifold  7 . Other configurations are contemplated. In certain instances, the hardware of the connection points  102  is partially or wholly integrated with the manifold  7 , so that the skid or trailer carrying the manifold  7  likewise carries the hardware for some or all of the connection points  102 . 
     The high pressure side connector  106  can take a number of different forms. For example, the high side connector  106  can be an iris type, with clamps that move on a spiral type path inward to effectuate clamping. In another instance, the high side connector  106  can be a cam actuated or rotational actuated type connector, a gate action connector (where one part swings over a shoulder an another part and locks), a notch connector (where a latching component is laid into a notch that locks it in place) or an internal latch (with an expanding latch that grips an internal profile. Other connector configurations are possible, and contemplated herein. 
     In certain instances, only the pump discharge line  12   b  is stabbed into the connection point  102 , and the pump suction line  12   a  is connected manually, using a length of hose with a manual connector  112  on its end that extends from the connection point  102  and is long enough to enable a worker making the connection to remain a safe distance from the high pressure of the manifold  7 . In other words, the hose is long enough to allow the worker to make the connection while staying out of the “red zone.” In certain instances, the low pressure side connector  112  is a stab connector—where a machined female bore internally receives and seals with a male stab. Typically the male stab includes seals that seal to the side wall of the inner female bore, but in certain instances, the seals could be provided on the female bore. The male stab can be provided on suction line  12   a  and the female provided as connector  112  or vice versa. In such a case, the low side connector  112  can rely on the high pressure side connector  106  to secure the male stab axially in the stab receptacle. 
     While illustrated and described as being at the manifold  7 , similar connection points  102  can be included elsewhere within the fracturing site  1 , such as at the fluid lines of fracturing tanks, blender, and elsewhere. Such connection points  102  allow components to be added and removed to the system quickly without depressurizing system components. 
       FIGS.  3 A- 3 B  are perspective views of an example connector  302 , which can be used as high side connector  106 , shown closed/engaged ( FIG.  3 A ) and open/disengaged ( FIG.  3 B ). The connector  302  is actuable in response to a signal (e.g., hydraulic, electric and/or other) to secure (i.e., lock) a tool to the fracturing stack  200  as well as any tools and other stack components positioned above the connector  302 , such as the lubricator  202  or BOP  204 . The connector  302  includes a housing  304 . The housing  304  carries a drive ring  306  that is rotatable relative to the housing  304 . The housing  304  receives a first line  310  from the manifold and a second line  312  from the pump  5  (e.g., discharge line  12   b  or suction line  12   a ), such that the housing is positioned around the lines. As illustrated, the drive ring  306  protrudes outward from an outer perimeter of the housing  304 . One or more clamps  308  (six are shown—each defining an arc segment of a circle) are within the housing to clamp to the lines  310 ,  312 . Each clamp  308  includes an attachment end  308   a  and a clamping end  308   b . The clamp  308  is movable between an engaged position ( FIG.  3 A ) and a disengaged position ( FIG.  3 B ). In the engaged position, the clamp  308  engages the second line  312  by the clamping end  308   b . In the disengaged position, the clamp  308  allows the well tool to become unrestrained from the connector  302 . 
     A linkage  402  is coupled to the drive ring  306 , the housing  304 , and the clamp  308 . The linkage  402  is movable between a first position supporting the clamp in the engaged position ( FIG.  3 A ) and a second position supporting the clamp in the disengaged position ( FIG.  3 B ). The linkage  402  is movable between the first position and the second position by rotating the drive ring  306 . 
       FIGS.  4 A- 4 B  are top-views of the example connector of  FIGS.  3 A- 3 B . As illustrated the connector has multiple linkages, one for each clamp. In some implementations, additional or fewer clamps and linkages can be used. In general, the linkages are configured to move concurrently with one another. For example, the linkages  402  are shown as all being coupled to the same drive ring  306 . 
     Each of the linkages includes a first arm  404  with a first end  404   a  and a second end  404   b . The first end  404   a  of the first arm  404  is hingedly coupled to the housing  304 . That is, the first end  404   a  of the first arm  404  has a single degree of freedom to rotate about a pivot point fixed to the housing  304 . This single degree of freedom is in the same plane as the drive ring  306 . A second arm  406  has a first end  406   a  and a second end  406   b . The first end  406   a  of the second arm  406  is hingedly coupled to the drive ring  306 . That is, the first end  406   a  of the second arm  406  has a single degree of freedom to rotate about a pivot point fixed to the drive ring  306 . This single degree of freedom is in the same plane as the drive ring  306 . The second end  406   b  of the second arm  406  is hingedly coupled to the second end  404   b  of the first arm  404 . The clamp  308  is coupled to the second end  404   b  of the first arm  404  and the second end  406   b  of the second arm  406 . The attachment end  308   a  of the clamp  308  is coupled to the second end  404   b  of the first arm  404  and the second end  406   b  of the second arm  406 . 
     The drive ring  306  is coupled to an actuator  408  configured to operate in response to a signal. In some implementations, the actuator  408  is a rotary actuator. In such instance, the drive ring  306  can include multiple teeth on an outer circumference of the drive ring  306 . The teeth can engage with a pinion gear on the rotary actuator  408 , which the rotary actuator  408  rotates to drive rotation of the drive ring  306 . In some implementations, the drive ring  306  can be coupled to a separate drive gear surrounding the first line  310  or the second line  312 . The separate drive gear can then be coupled to the actuator  408 . In some implementations, a chain drive can be used to connect the actuator gear to the drive ring or the drive gear. In some implementations, all or part of the gearing system may be retained and protected within the housing  304 . In some implementations, the actuator  408  can be a linear actuator. In such an implementation, the actuator is attached directly to the drive ring  306  by a linkage, such that when the actuator  408  extends, linearly, it rotates the drive ring  306 . 
       FIG.  5    is a side cross-sectional view of an example connector in the closed position. The first line  310 , the second line  312 , and the housing  304  are aligned on a common center axis  502  (i.e., concentric), and the line  312  has a male stab  514  that is received and sealed in a female receptacle  512  of line  310  (or vice versa). The drive ring  306  is rotatable about the common center axis  502 . As illustrated, the first line  310  and the second line  312  have hubs  508   a ,  508   b  at their ends that form a male profile  504  when mated together and the first line  310  stabs into the second. The clamps  308  each have a female profile  506  shaped to receive the male profile  504 . The combination of profiles allows the connector to lock the first line  310  and the second line  312  together, as the female profile  506  axially bounds the male profile  504 —holding the two lines  310 ,  312  axially together—and the clamps  308  circumferentially enclose the male profile  504 —laterally holding the two lines  310 ,  312  together. 
     In some implementations, a pressure port  508  in the first line  310  communicates to the interior bore of the lines  310 ,  312 . A pressure sensor connected at this pressure port  508  can sense the pressure within the interior bore of the lines  310 ,  312 . 
     As shown in  FIG.  6   , the latch  308  can include one or more bumpers or stops  510  to limit the motion of the clamps  308 . The stops  510  are affixed to the housing  304  and are positioned relative to each clamp  308  such that when the clamp  308  is fully disengaged from the lines  310 ,  312  the clamp  308  abuts the stops  510 . The stops  510  align the clamp  308  relative to the center axis  502 , with the center of clamp&#39;s arc segment being near or at the center axis  502 . The stops  510  can be secured to the housing  304  in a variety of ways, such as being fastened to a top cover (not shown) of the housing  304 . In some implementations, two soft stops  510  are used for each clamp, but additional or fewer stops can be used. 
       FIG.  6    illustrates a side perspective view of the connector  302  with a guide cone  602  that funnels the second line  312  to concentrically align on the center axis  502  as it is stabbed into the guide cone  602  and then into the first line  310 . The guide cone  602  is suitable for use as guide cone  110  ( FIG.  2   ). 
       FIG.  7    also shows a system of proximity switches  604  to detect the open/closed/intermediate state of the connector  302 . The proximity sensors  604  are mounted on the housing  304  to sense the position of a corresponding magnet  608  affixed to the drive ring  306 . When the drive ring  306  is rotated to engage the clamps to the first and second line  310 , 312 , the magnet  608  is adjacent one proximity sensor  604  and when the drive ring  306  is rotated to disengage the clamps, the magnet  608  is adjacent the opposing proximity sensor  604 . As discussed below, a controller can determine the state of the latch using the proximity sensors  604  and, in turn, operate an electronic interlock. 
       FIG.  7    also shows a drain assembly  606  that extends through the side of the housing  304 . The drain assembly  606  can operate as bleed  48  ( FIG.  2   ). The drain assembly  606  protrudes into the bore of the connector  302  to be in fluid communication with the bores of the first and second lines  310 ,  312 , and can be actuated open to drain fluid from the bore or actuated closed to seal against draining fluid. Thus, the drain assembly  606  can be used to equalize pressure between the central bore and the outside environment. 
       FIGS.  8 A- 8 B  are a perspective view and a half cross-sectional view, respectively, of an example drain assembly  606 . The example drain assembly includes a drain valve  702  and a hydraulic interlock  704 . The hydraulic interlock  704  includes a push button valve  703 —a type of valve with a hydraulic input  706 , a hydraulic output  708  and a valve state push button  710  that, when pushed in, opens the valve to pass fluid between the input  706  and output  708  and that, when not pushed in, seals against passage of fluid between the input  706  and output  708 . In use, the valve  702  is connected between the hydraulic pump that would, in other circumstances, supply hydraulic pressure to power a hydraulic-driven, drive ring actuator used to operate the connector  302 . Thus, the hydraulic input  706  is connected to the hydraulic pump while the hydraulic output  708  is connected to the hydraulic actuator (e.g., actuator  408  of  FIG.  4 A ). The valve state button  710  interacts with a tab  712  on the drain valve  702 . When the drain valve  702  is in a closed position, the tab  712  abuts and presses against the valve state button  710 . The pressure applied by the tab  712  on the valve state button  710 , pushes the button  710  in and puts the valve in a closed state. In the closed state, hydraulic fluid is sealed against passing from the input  706  to output  708 , and onward to drive the drive ring actuator. In this state, the actuator for the drive ring can receive no pressure and the connector  302  is locked out and cannot operate to open. When the drain valve  702  is in an open position, the tab  712  is moved from the valve state button. The valve state button  710  is allowed to protrude outward, and the valve  702  moves to an open state. In the open state, hydraulic fluid can pass between input  706  and output  708  and onward to drive the hydraulic actuator. In this state, the actuator for the drive ring is able to receive hydraulic pressure and can be operated to open. In some implementations, an electrical proximity switch  714  can be included signal a state of the drain valve  702 , the hydraulic interlock  704 , or both. 
     Referring to  FIG.  8 B , the operation of the drain valve  702  is described. An end portion of the drain valve  702  is inserted through an aperture in the sidewall of the housing  304  of connector  302 , so that a plunger  758  of the valve  702  is in the bore of the housing. The outer surface of the drain valve  702  has seals  764  that seal to the inner diameter of the aperture, sealing the drain valve  702  to the housing. The drain valve  702  is secured to the housing  304  with threads  760 . When the drain valve  702  is in a closed position (as illustrated), the plunger rests on a seat  762 . The seat  762  seals against passage of fluid into an interior cavity  768  of the valve  702 . The seat  762  can be a metal-to-metal seat, an elastomer seat, or another type of seat. When the drain valve  702  is in an open position, the plunger  758  is moved apart from the seat  762  by the valve stem  756 . Separating the plunger  758  from the seat  762  allows fluid to flow from the central bore of the housing  304 , through the cavity  768  to an outlet  770 . The movement of the valve stem  756  to open/close the plunger  758  is controlled by an actuator. In  FIG.  8 B , the actuator is a hydraulic actuator that includes a pressure inlet  750  configured to be connected to a hydraulic source, such as the hydraulic pump connected to the valve of the interlock  704  or another source, and which itself may have a control valve to gate pressure to the inlet  750 . The pressure inlet  750  is fluidically connected to a spring-loaded piston  752  affixed to the valve stem  756 . When pressure is applied through the inlet  750 , it acts on the piston  752  driving it toward the right in  FIG.  8 B . The piston  752 , in turn, also drives the valve stem  756  to the right, opening the valve  702  by moving the plunger  758  off the seat  762 . The spring-loaded piston is biased to the left in  FIG.  8   b   , so as to cause the valve  702  to “fail closed.” That is, when there is no hydraulic pressure at the pressure inlet  750 , the spring  754  of the spring-loaded piston  752  will force the drain valve  702  into the closed position shown in  FIG.  8 B . 
     Although described with the hydraulic interlock above, the connector  302  can be alternatively or additionally implemented with an electronic interlock. For example, a controller (e.g., controller  51 ) can monitor pressure in the central bore (e.g., via a pressure sensor in port  508  or elsewhere). If pressure above a threshold pressure is sensed in the bore, the controller can refuse to actuate the connector  302  to open (e.g., refuse to signal actuator  408  to operate) until the pressure drops below the threshold pressure. 
     As shown in  FIG.  9   , the well fracking site  1  can include a controller  51  to, among other things, monitor pressures of the operating volumes and send signals to actuate valves and/or connectors. As shown in  FIG.  9   , the controller  51  can include a processor  1002  (implemented as one or more local or distributed processors) and non-transitory storage media (e.g., memory  1004 —implemented as one or more local or distributed memories) containing instructions that cause the processor  1002  to perform the methods described herein. The processor  1002  is coupled to an input/output (I/O) interface  1006  for sending and receiving communications with other equipment of the well fracking site  1  ( FIG.  1   ) via communication links  53  ( FIG.  2   ). In certain instances, the controller  51  can communicate status with and send actuation and control signals to one or more of the connectors  106 ,  112 , the valves  44 ,  46  and other valves, including main valves and a swab valve of a fracturing stack, a BOP, a lubricator (and its tool trap), a well drop launcher, as well as various sensors (e.g., pressure sensors, temperature sensors and other types of sensors) at the well site. In certain instances, the controller  51  can communicate status and send actuation and control signals to one or more of the systems on the well site  1 , including the blenders  3 , fracking pumps  5  and other equipment on the well site  1 . The communications can be hard-wired, wireless or a combination of wired and wireless. In some implementations, the controller  51  can be located remote from the manifold, such as in the data van  6 , elsewhere on the well site  1  or even remote from the well site  1  (e.g., at a central monitoring facility for monitoring and controlling multiple well sites). In some implementations, the controller  51  can be a distributed controller with different portions located about the well site  1  or off site. For example, in certain instances, a portion of the controller  51  can be distributed among individual connection points  102 , while another portion of the controller  51  can be located at the data van  6  ( FIG.  1   ). 
     The controller  51  can operate in monitoring, controlling, and using the well fracturing site  1  for introducing or removing high pressure equipment from the manifold  7 . To monitor and control the manifold  7 , the controller  51  is used in conjunction with sensors to measure the pressure of fluid at various connection points of the manifold  7 . Input and output signals, including the data from the sensors and actuators, controlled and monitored by the controller  51 , can be logged continuously by the controller  51 . 
     For example, an operator, via the controller  51 , can orchestrate the connection/disconnection/swap of a pump  5  at a connection point  102  of the manifold  7  ( FIG.  2   ). Notably, the human operator can operate the controller  51 , and thus the resulting physical steps, at a safe distance from the high pressure lines, far enough that if there were a high pressure leak or failure, the operator would not be injured. The operation can be effectuated via a terminal or other control interface associated with the controller  51 . In certain instances, the operator, via controller  51 , actuates a fully automated sequence run by the controller  51  to perform the below described steps (i.e., the operator just presses start, or similar, and the controller  51  performs autonomously). Alternatively, the operator, via controller  51 , commands one or more of the individual, below described steps. In either instance, the terminal can present menu items to the operator that present the operator&#39;s options in commanding the controller  51 . 
     If the manifold  7  is at pressure, for example, with one or more of the pumps  5  connected to the manifold  7  pumping at frac pressure or at some other pressure, the manifold  7  need not be depressurized to connect another pump  5 . When the manifold  7  is at pressure and no pump is connected to a certain connection point  102 , the high side valve  44  and low side valve  46  of that connection point  102  are in a closed position. The truck  8  with the pump  5  is backed up to the connection point  102 , and the pump discharge line  12   b  and pump suction line  12   a  are connected to their respective corresponding lines at the connection point  102 . In certain instances, backing the truck  8  up to the manifold  7  stabs the pump discharge line  12   b  and the pump suction line  12   a  into their respective counterparts at the connection point  102 . In instances where the low pressure side includes a length of hose with a manual connector  112  on its end, such a manual connection can be made before the truck  8  is fully positioned to stab the discharge line  12   b  into its counterpart at the connection point  102 , or could be made after. 
     Thereafter, the controller  51  signals the high side connector  106  to actuate closed, securing and sealing the discharge line  12   b  to its counterpart at the connection point  102 . If the low side connector  112  at the suction line  12   a  is an actuable connector (as opposed to the stab receptacle, described above, or a manual connector), the controller  51  signals the low side connector  112  to actuate closed, securing and sealing the suction line  12   a  to its counterpart at the connection point  102 . 
     The controller  51  then actuates the valves  44  and  46  to open. Typically, the valve  46  on the low pressure side is opened first. This allows the pump  5  to be operated to bring pressure in the discharge line  12   b  up to the pressure or near the pressure in the manifold  7 . After verifying the pressure is equalized across the valve  44 , the controller  51  signals the valve  44  to open. The controller  51  can determine the pressures on either side of the valves  44  and  46  by receiving signals from the pressure sensors  210   a ,  210   b  on the high pressure line and sensors  212   a ,  212   b  on the low pressure line. For example, if the pressure differential, as determined from sensors  210   a  and  210   b , is above a threshold differential, the controller  51  will not allow valve  44  on the high pressure side to open. The threshold differential, in certain instances, is determined to ensure the valve  44  does not open in an unsafe condition. 
     With the valves  44 ,  46  open, the pump  5  can be operated to pump frac fluid received through the suction line  12   a  to the discharge line  12   b , into the manifold  7  and on to the well. In certain instances, the controller  51  can be coupled to the pump  5  to actuate the pump to begin and stop pumping, control its rate and control other operational characteristics of the pump  5 . 
     If a pump  5  needs to be removed from the manifold  7  while the manifold  7  is at pressure, for example if the pump  5  needs maintenance or fails or is no longer needed in the operation, the pump  5  is shut down and the controller  51  actuates the valve  44  on the high pressure side to close and then actuates the valve  46  on the low pressure side to close. Thereafter, the controller  51  actuates the bleeds  48  on both the high and low pressure sides to open and depressurize the suction line  12   a  and discharge line  12   b . The controller  51  monitors pressure at least via pressure sensor  210   a , to determine whether the pressure has dropped below a specified threshold pressure before actuating connector  106  to the discharge line  12   b  open and release the pump  5  from the connection point  102 . The specified threshold pressure can be selected to ensure that the connector  106  does not open in an unsafe condition. In instances where the low side connector  112  is actuable, the controller  51  can monitor pressure via the pressure sensor  212   b  and compare the pressure to a second threshold pressure before actuating low side connector  112  to open. Once disconnected, the truck  8  carrying the pump  5  can drive off. Another pump  5  can be connected to the manifold  7  at the empty connection point  102  without depressurizing the manifold  7 , as described above. 
     The concepts described herein can, in certain instances, yield a number of advantages. For example, the operations can manifest a significant time, and thus cost, savings because, the fracturing equipment, including the manifold and associated lines, need not be pressured up and down to remove, add or change out a pump. Furthermore, pressure testing between replacing pumps can be reduced or eliminated. Cost savings can be had in fuel/energy, operator and equipment costs that would otherwise have been incurred in pumping the well and such a large volume of the fracking stack, manifold and related equipment up to pressure, both for pressure testing and pressurizing back up to fracturing pressure in performing the fracturing. Savings due to wear on equipment can also be realized, as the maintenance (e.g., repair of worn parts and greasing) on the surface equipment is reduced due to the reduction in pressure cycling. Finally, savings can be realized in reduction of non-productive operator time associated with repairing leaks that can occur from pressurizing/depressurizing multiple valves and lines of the surface equipment. Beyond time and cost saving, the operations can be safer, as personnel can remain out of the “red zone” and are not exposed to the related hazardous conditions. 
     A number of implementations of the have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other implementations are within the scope of the following claims.